Can Diet and Lifestyle influence your Risk of getting Cancer? 1,000+ Studies Analyzed (2024)

By Dr Frank Yap, MD - July 23, 2024

Can diet, supplements and lifestyle influence cancer risk? Dive into 1,000+ research studies to find out.

Most of us know Steve Jobs, Chadwick Boseman (Black Panther), Robin Gibb (Bee Gees), Donna Summer, Farrah Fawcett, Eartha Kitt, Peter Jennings, Paul Newman, Patrick Swayze, Sydney Pollack, Michael Crichton, Bob Denver, Ted Kennedy, Jerry Orbach, Anne Bancroft, William Rehnquist, and Tony Snow, just to name a few. What do they have in common? They all died from 'cancer'.

Current large language models (LLMs) like ChatGPT, Gemini from Google and Copilot from Microsoft might return generic answers to your questions. While these can be a starting point, they often lack the depth you might crave.

That's where this article comes in. We've delved into the research to provide you with more than just basic advice. We've done the research, so that you don't have to. We'll not only share supporting evidence, but also explain our methodology for selecting the most valuable information.

Prevention holds greater value than both cure and early detection. Nonetheless, the incentive for profit often leans away from investing in preventive measures. This tendency is reflected in the limited coverage of preventative strategies within mainstream media channels.

The quest for cancer prevention and treatment has been shrouded in ambiguity when it comes to the world of dietary supplements. The bewildering array of options leaves us questioning their efficacy, for without robust scientific evidence, their true potential remains enigmatic.

Can foods and diet really influence your risk of getting cancer? What types of foods reduce your risk and types that might increase your risk? What about vitamin and mineral supplements? Can supplements reduce your cancer risk or do they actually increase your cancer risk? We have answers to all of these questions and more.

This article here is developed as a consumer guide and is not meant to share the various technical theories related to cancer but to share practical preventive strategies that we could put into action immediately.

The goal of this article is to summarize the relevant, updated and practical points so that you could have your personal blue-print to prevent and how to give yourself the best possible outcome if you get cancer. We have filtered out all those unproven ‘internet noise’ out there in the virtual world and have summarized the overwhelming information out there into the following list of ‘actionable’ strategies.

AACR Cancer Progress Report 2023

What is Cancer?

Cancer is the name given to a collection of related diseases. In all types of cancer, some of the body’s cells begin to divide without stopping and spread into surrounding tissues. (National Cancer Institute)

Genetic changes that cause cancer can be inherited from our parents. They can also arise during a person’s lifetime as a result of errors that occur as cells divide or because of damage to DNA caused by certain environmental exposures. Cancer-causing environmental exposures include substances, such as the chemicals in tobacco smoke, and radiation, such as ultraviolet rays from the sun. As shown from the image below, environmental factors contribute up to 95% of cancers.

There are many types of cancer treatment. The types of treatment that you receive will depend on the type of cancer you have and how advanced it is. Surgery, radiation, and chemotherapy are the standard types of treatment for cancer. While your cancer specialist is focusing on staging your disease, the type of surgery, radiotherapy or chemotherapy, many people tend to lose focus on their nutrition. There is also a lot of confusion due to the overwhelming mixing of credible scientific information and marketing hypes available on the internet.

There are also many phoney “cancer treatment” with amazing claims but devoid of any scientific data to back them up, typical of health scams. Cancer is a life threatening disease and therefore many consumers fell prey to these phoney cancer treatments.

Cancer and Nutrition

When you’re healthy, eating enough food to get the nutrients and calories you need is not usually a problem. Most nutrition guidelines stress eating lots of vegetables, fruits, and whole-grain products; limiting the amount of red meat you eat, especially meats that are processed or high in fat; cutting back on fat, sugar, alcohol, and salt; and staying at a healthy weight. But when you’re being treated for cancer, these things can be hard to do, especially if you have side effects or just don’t feel well.

Good nutrition is especially important if you have cancer because both the illness and its treatments can change the way you eat. They can also affect the way your body tolerates certain foods and uses nutrients.

During cancer treatment you might need to change your diet to help build up your strength and withstand the effects of the cancer and its treatment. This may mean eating things that aren’t normally recommended when you are in good health. For instance, you might need high-fat, high-calorie foods to keep up your weight, or thick, cool foods like ice cream or milk shakes because sores in your mouth and throat are making it hard to eat anything. The type of cancer, your treatment, and any side effects you have must be considered when trying to figure out the best ways to get the nutrition your body needs.

Therefore, nutrition is not an option or a desire but rather a basic necessity. That makes it all the more important reason to make nutrition as part of your overall strategy to fight the cancer battle. Do not give up. Many people with cancer have been cured or survived longer than those without cancer.

The following are the essential things you should know about nutrition and cancer.

Diet and Cancer Prevention

Please remember that reducing your risk of getting cancer doesn’t simply depend on a single stand alone strategy or nutrient or supplement. Even if you zealously practise a healthy lifestyle and consume various supplements, you can still fall victim to this disease if you fail to address your other risk factors.

The umbrella review, published in May 2024 in PLOS One, evaluated 48 previous reviews and meta-analyses published between 2000 and 2023 and concluded that vegetarian or vegan diets “significantly reduce the risk” of ischemic heart disease, gastrointestinal cancer, and prostate cancer, as well as associated mortality.

Caution: What are the nutrients of concern for vegetarians and vegans? Vitamin B12 and K2. Anybody who is eating a vegan diet or a vegetarian diet or just a mostly plant-based diet should be taking vitamin B12 and K2 supplements. Vitamin B12 is only found in significant amounts in animal products and fortified foods, and a deficiency can cause anemia, mood changes, or permanent neurological damage. Plant-based diets may also be low in vitamin D, omega-3 fatty acids, and minerals like iodine, selenium, iron, and zinc.

Another 2024 umbrella review (BMJ) of the literature confirmed what multiple studies have shown — the higher your intake of ultraprocessed food, the higher your risk of adverse health outcomes. The analysis, which included 45 unique pooled analyses and 9,888,373 participants, found direct associations between 32 health parameters and exposure to ultra processed food, including metabolic dysfunction, cancer, mental, respiratory, cardiovascular and gastrointestinal issues, as well as all-cause mortality**.

*Umbrella review: An umbrella review, or a review of reviews, is a systematic review that only considers other systematic reviews as an eligible study type for inclusion. An umbrella review compiles evidence from multiple existing reviews and is one of the strongest and highest levels of evidence.

**All-cause mortality: "Death from anything" may be a clearer term for the layperson as opposed to 'All-cause mortality'. This is one of the best measures for the factors that increase the risk of what eventually and most likely will take someone's life.

Carbohydrates (Macronutrient)

Carbohydrates are the body’s major source of energy. Carbohydrates give the body the fuel it needs for physical activity and proper organ function. The best sources of carbohydrates – fruits, vegetables and whole grains – also supply needed vitamins and minerals, fiber and phytonutrients to the body’s cells. (Phytonutrients are chemicals in plant-based foods that we don’t need to live, but that might promote health.)

Whole grains or foods made from them contain all the essential parts and naturally occurring nutrients of the entire grain seed. Whole grains are found in cereals, breads, flours, and crackers. Some whole grains, such as quinoa, brown rice, or barley, can be used as side dishes or part of an entree.

Fiber is the part of plant foods that the body cannot digest. There are 2 types of fiber. Insoluble fiber helps to move food waste out of the body quickly, and soluble fiber binds with water in the stool to help keep stool soft.

Other sources of carbohydrates include bread, potatoes, rice, spaghetti, pasta, cereals, corn, peas, and beans. Sweets (desserts, candy, and drinks with sugar) can supply carbohydrates, but provide very little in the way of vitamins, minerals, or phytonutrients.

As mentioned above, the BMJ 2024 umbrella review of the literature confirmed what multiple studies have shown — the higher your intake of ultraprocessed food, the higher your risk of adverse health outcomes. The analysis, which included 45 unique pooled analyses and 9,888,373 participants, found direct associations between 32 health parameters and exposure to ultra processed food, including metabolic dysfunction, cancer, mental, respiratory, cardiovascular and gastrointestinal issues, as well as all-cause mortality.

This harmful "ultra-processed" food, as the researchers called it, may include packaged sweet pastries and muffins, chips, candy, sodas, frozen dinners like meatballs and fish sticks, instant ramen noodles, sugary cereals, and pretty much anything else you can imagine that's cheap and comes in a ready-to-go packet or container at the store.

Evidence from another umbrella review (BMJ 2023) of more than 8,000 studies supports the limiting dietary sugar recommendation.

Fats (Macronutrient)

Fats play an important role in nutrition. Fats and oils are made of fatty acids and serve as a rich source of energy for the body. The body breaks down fats and uses them to store energy, insulate body tissues, and transport some types of vitamins through the blood.

You may have heard that some fats are better for you than others. Choose monounsaturated and polyunsaturated fats more often than saturated fats or trans fats.

Monounsaturated fats are found mainly in vegetable oils like olive, canola, and peanut oils. Polyunsaturated fats are found mainly in vegetable oils like safflower, sunflower, corn, and flaxseed. They are also the main fats found in seafood.

Saturated fats are mainly found in animal sources like meat and poultry, whole or reduced-fat milk, cheese, and butter. Some vegetable oils like coconut, palm kernel oil, and palm oil are saturated. Trans-fatty acids are formed when vegetable oils are processed into margarine or shortening. Sources of trans fats include snack foods and baked goods made with partially hydrogenated vegetable oil or vegetable shortening. Trans fats also are found naturally in some animal products, like dairy products. Trans fats can raise bad cholesterol and lower good cholesterol; try to eliminate them from your diet.

Researchers estimated that during the heyday of trans fats in the 1990s, they led to roughly 50,000 preventable deaths every year in the US. The US FDA rolled out a near-universal ban on trans fats in June 2015.

Proteins (Macronutrient)

We need protein for growth, to repair body tissue, and to keep our immune systems healthy. When your body doesn’t get enough protein, it might break down muscle for the fuel it needs. This makes it take longer to recover from illness and can lower resistance to infection. People with cancer often need more protein than usual. After surgery, chemotherapy, or radiation therapy, extra protein is usually needed to heal tissues and help fight infection.

Muscle mass optimizes you for longevity, and dietary protein, especially animal-based protein, is essential for muscle maintenance and muscle building. The greater your muscle mass, the higher your survivability against all diseases, including cancer. Cachexia, for example — the loss of muscle mass — accounts for 20% of all cancer deaths. (source)

One of the reasons for this is because muscle acts as a reservoir for amino acids, which are crucial during illness when your body’s demand for them increases.

Good sources of protein include fish, poultry, lean red meat, eggs, low-fat dairy products, nuts and nut butters, dried beans, peas and lentils, and soy foods.

Water

Water and liquids or fluids are vital to health. All body cells need water to function. If you do not take in enough fluids or if you lose fluids through vomiting or diarrhea, you can become dehydrated (your body doesn’t have as much fluid as it should). If this happens, the fluids and minerals that help keep your body working can become dangerously out of balance. You do get some water from the foods you eat, but a person should drink about eight 8-ounce glasses of liquid each day to be sure that all the body cells get the fluid they need. You may need extra fluids if you are vomiting or have diarrhea. Keep in mind that all liquids (soups, milk, even ice cream and gelatin) count toward your fluid goals.

Quit smoking

Cigarette smoking topped the charts as the leading risk factor, contributing to nearly 20 percent of all cancer cases and close to 30 percent of cancer deaths. Smoking comprised 56 percent of potentially preventable cancers in men and almost 40 percent of those in women. (Journal of the American Cancer Society 2024)

Journal of the American Cancer Society 2024

If you are a non smoker, then your risk of cancer will be reduced. Smoking is by far the leading risk factor for lung cancer. In the early 20th century, lung cancer was much less common than some other types of cancer. But this has changed once manufactured cigarette became readily available and more people began smoking.

Avoid tobacco products altogether, including cigarettes, cigars, and smokeless tobacco. About 80% of lung cancer deaths are thought to result from smoking. The risk for lung cancer among smokers is many times higher than among non-smokers. The longer you smoke and the more packs a day you smoke, the greater your risk.

On top of that, you should also try to cut down on your visits to places where people tend to smoke e.g. pubs etc. Passive smoking is just as bad.

Body Weight and Physical Activity

For those of you who do not use tobacco, one of the most important cancer risk factors that can be modified are body weight, diet, and physical activity. One-third of all cancer deaths in the United States each year are linked to diet and physical activity, including being overweight or obese, while another third is caused by tobacco products.

Next to cigarette smoke, excess body weight was the second main modifiable risk factor, contributing to 7.6 percent of potentially preventable cancers, followed by alcohol consumption at 5.4 percent, UV radiation exposure at 4.6 percent, and physical inactivity at 3.1 percent. (Journal of the American Cancer Society 2024)

Although our genes influence our risk of cancer, most of the difference in cancer risk between people is due to factors that are not inherited. Avoiding tobacco products, staying at a healthy weight, staying active throughout life, and eating a healthy diet may greatly reduce a person's lifetime risk of developing or dying from cancer. These same behaviors are also linked with a lower risk of developing heart disease and diabetes.

Many consumers are also unaware that grilling some popular food items can produce cancer-causing compounds called heterocyclic amines (HCAs). For more information on foods that contain the highest concentrations of HCAs: http://www.cancerproject.org/media/news/fiveworstfoodsreport.php. HCAs, a family of mutagenic and cancer-causing compounds, are produced during the cooking of many animal products, including chicken, beef, pork, and fish. In January of 2005, the federal government officially added HCAs to its list of known carcinogens.

These are the summary recommendations from the ACS Guidelines on Diet and Physical Activity for Cancer Prevention (2020):

Achieve and maintain a healthy weight throughout life.

Keep your weight within the healthy range, and avoid weight gain in adult life.

Follow a healthy eating pattern at all ages.

A healthy eating pattern includes:

Foods that are high in nutrients in amounts that help you get to and stay at a healthy body weight
A variety of vegetables – dark green, red and orange, fiber-rich legumes (beans and peas), and others
Fruits, especially whole fruits in a variety of colors
Whole grains

A healthy eating pattern limits or does not include:

Red and processed meats
Sugar-sweetened beverages
Highly processed foods and refined grain products

Be physically active.

Adults: Get 150-300 minutes of moderate intensity or 75-150 minutes of vigorous intensity activity each week (or a combination of these). Getting to or exceeding the upper limit of 300 minutes is ideal.
Children and teens: Get at least 1 hour of moderate or vigorous intensity activity each day.
Limit sedentary behavior such as sitting, lying down, watching TV, and other forms of screen-based entertainment.

It is best not to drink alcohol.

People who do choose to drink alcohol should have no more than 1 drink per day for women or 2 drinks per day for men.

In a 2020 review published in BMJ, key messages were:

Obesity and alcohol increase the risk of several types of cancer; these are the most important nutritional factors contributing to the total burden of cancer worldwide
For colorectal cancer, processed meat increases risk and red meat probably increases risk; dietary fibre, dairy products, and calcium probably reduce risk
Foods containing mutagens can cause cancer; certain types of salted fish cause nasopharyngeal cancer, and foods contaminated with aflatoxin cause liver cancer
Fruits and vegetables are not clearly linked to cancer risk, although very low intakes might increase the risk for aerodigestive (airway and digestive tracts) and some other cancers.

The Mediterranean-DASH diet

The Mediterranean-DASH diet combines elements of the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) diet. Here’s what we know:

Mediterranean Diet and Cancer: The Mediterranean diet is characterized by high consumption of vegetables, fruits, whole grains, and olive oil, while limiting meat, sweets, and saturated fat.

Research suggests that the Mediterranean diet is linked to lower risks of cancer and may help alleviate symptoms and imbalances common among people with cancer. The abundance of antioxidants and cancer-fighting phytochemicals in this diet contributes to its potential protective effects against cancer.

MIND Diet and Breast Cancer Risk: A 2022 study investigated the association between the MIND diet and breast cancer risk among Tehranian adult women. The study included 134 women with recently diagnosed breast cancer (confirmed histologically) and 272 women of the same age as controls. Results showed that individuals in the highest tertile of the MIND diet had a 45% lower risk of breast cancer compared to those in the lowest tertile.

Olive Oil

Olive oil is loaded with health benefits, so it’s no wonder it’s one of the staples of the Mediterranean diet. There are more than 1,200 search results on olive oil and cancer on PubMed.

A meta-analysis of 45 studies published in 2022 found that people who consume olive oil daily have a 31 percent lower risk of any cancer compared to those who consume olive oil less frequently.

Studies Confirm Importance of Strength Training in Moderation

Among them is a systematic review and meta-analysis of 16 studies published in the British Journal of Sports Medicine in 2022.

Muscle-strengthening activities were associated with a 10% to 17% lower risk of cardiovascular disease (CVD), total cancer incidence, Type 2 diabetes and all-cause mortality. As in O’Keefe’s study, this review found a J-shaped association, with a maximum risk reduction of all-cause mortality, CVD and cancer (10 % to 20%) being observed at a dose of 30 to 60 minutes per week.

After 60 minutes, the benefits of strength training started to diminish, and above 140 minutes per week, it was associated with an increased risk of all-cause mortality.

Another 2022 systematic review published in the American Journal of Preventive Medicine (AJPM) found that:

“Compared with undertaking no resistance training, undertaking any amount of resistance training reduced the risk of all-cause mortality by 15% ... cardiovascular disease mortality by 19% ... and cancer mortality by 14% ...

A dose-response meta-analysis of 4 studies suggested a nonlinear relationship between resistance training and the risk of all-cause mortality. A maximum risk reduction of 27% was observed at around 60 minutes per week of resistance training ... Mortality risk reductions diminished at higher volumes.”

Weight Loss: Achieve and maintain a healthy weight throughout life

Being at a healthy weight might lower the risk of some types of cancer. These include cancer of the breast, prostate, lung, colon and kidney.

Physical activity counts too. Besides helping control weight, physical activity on its own might lower the risk of breast cancer and colon cancer.

Doing any amount of physical activity benefits health. But for the most benefit, strive for at least 150 minutes a week of moderate aerobic activity or 75 minutes a week of hard aerobic activity.

You can combine moderate and hard activity. As a general goal, include at least 30 minutes of physical activity in your daily routine. More is better.

The American Cancer Society released guidelines in 2020 for reducing the risk of cancer.

The recommendations include the latest research on diet and physical activity, as well as policy and systems changes that reduce barriers to healthy living. The update focuses on increasing physical activity and developing healthy eating patterns at every age.

Avoid excess weight gain at all ages. For those who are overweight or obese, losing even a small amount of weight has health benefits and is a good place to start.

Get regular physical activity and limit intake of high-calorie foods and drinks as keys to help maintain a healthy weight.

Adults: Get at least 150 minutes of moderate intensity or 75 minutes of vigorous intensity activity each week (or a combination of these), preferably spread throughout the week.

Children and teens: Get at least 1 hour of moderate or vigorous intensity activity each day, with vigorous activity on at least 3 days each week.

Limit sedentary behavior such as sitting, lying down, watching TV, and other forms of screen-based entertainment.

Fasting and Cancer

Fasting may help reduce obesity-associated cancers. “There’s a lot of obesity-associated cancers,” said Dr. Jason Fung, a nephrologist and fasting expert. “There’s about 13 cancers that are well accepted that they are associated with obesity; fasting might help decrease that.”

Fasting can potentially starve cancer cells. When fasting, the body uses fats and produces ketones for energy. Cancer cells rely heavily on glucose, making them less efficient at using ketones.

Additionally, fasting reduces insulin levels. Elevated insulin levels are linked to an increased risk of breast, prostate, and colorectal cancers. Eating continuously can contribute to hyperinsulinemia.

That said, not every type of fasting is effective and safe. Intermittent fasting is the preferred option. Extended or extreme fasting can be counter-productive.

Related: Fasting as an Effective Anti-Cancer Strategy: Inspiring Success Stories

Best Cancer Fighting Foods

What are the most powerful cancer fighting foods? No single food can protect you against cancer by itself.

But research (American Institute of Cancer Research) shows that a diet filled with a variety of vegetables, fruits, whole grains, beans and other plant foods helps lower risk for many cancers. In laboratory studies, many individual minerals, vitamins and phytochemicals demonstrate anti-cancer effects. By including more foods that fight cancer into your diet, you will help reduce your risk of developing cancer.

The development of cancer, in particular, has been shown to be heavily influenced by your diet. The term “superfood” is a fairly new term referring to foods that offer maximum nutritional benefits for minimal calories.

Do take note that we are talking about foods to prevent your risk of cancer and not about treating cancer with foods. Cancer treatments will be something that you will need to discuss with your cancer specialist.

Many foods contain beneficial compounds that could help decrease the growth of cancer. There are also several studies showing that a higher intake of certain foods could be associated with a lower risk of the disease.

Some doctors and media channels argue that there is very little evidence to support the use of foods to prevent cancer.

We will delve into the research and look at a list of foods that may lower your risk of cancer.

1. Vegetables (Tomato, Broccoli, Carrot)

Observational studies have linked a higher consumption of vegetables with a lower risk of cancer (Trusted Source, Trusted Source, Trusted Source). Many vegetables contain cancer-fighting antioxidants and phytochemicals.

A 2022 umbrella review* of 41 systematic reviews and meta-analyses of 303 observational studies

revealed that CV (cruciferous vegetable intake might be associated with beneficial effects on several health-related outcomes (gastric cancer, lung cancer, endometrial cancer, and all-cause mortality).

*Umbrella review: An umbrella review, or a review of reviews, is a systematic review that only considers other systematic reviews as an eligible study type for inclusion. An umbrella review compiles evidence from multiple existing reviews and is one of the strongest and highest levels of evidence.

Vegetables, such as tomatoes and carrots, are linked to a decreased risk of prostate, stomach and lung cancer (Trusted Source, Trusted Source, Trusted Source, Trusted Source).

It has long been known that tomato consumption reduces the risk of developing cancer and cardiovascular disease, due to its high lycopene content (Ratto 2022). There are more than 1,500 search results on lycopene and cancer on PubMed.

In a 2020 prospective study of 27,934 Adventist men, published in the journal Cancer Causes & Control (The Adventist Health Study 2) found that men who ate tomatoes almost every day had a 28 percent lower risk of prostate cancer than men who didn’t. Lycopene may also protect the skin from the sun damage that can cause skin cancer, and some research suggests that it helps women maintain bone mass as they age.

A review of 17 studies also found that a higher intake of raw tomatoes, cooked tomatoes and lycopene were all associated with a reduced risk of prostate cancer (J Nutr Sci Vitaminol. 2013).

Broccoli contains sulforaphane, a plant compound found in cruciferous vegetables that may have potent anticancer properties. There are more than 1,000 search results on broccoli and cancer on PubMed.

One analysis of 35 human studies showed that eating more cruciferous vegetables was associated with a lower risk of colorectal and colon cancer (Ann Oncol. 2013).

Another 2015 analysis looked at the results of five studies and concluded that eating carrots may reduce the risk of stomach cancer by up to 26% (Source).

Try incorporating carrots into your diet as a healthy snack or delicious side dish just a few times per week to increase your intake and potentially reduce your risk of cancer.

Carrot is also listed in the EWG's Clean 15. These 15 items had the lowest amounts of pesticide residues, according to EWG’s analysis of the most recent USDA data.

Caution and Concern

It wasn't long ago that, after finding that people who ate a diet rich in foods containing beta-carotene had a lower risk of lung cancer, researchers set out to study the potential effect of supplements of beta-carotene on risk. Unlike the reduced risk seen with dietary beta-carotene, however, beta-carotene in supplement form was associated with an increased risk of developing the disease.

2. Olive Oil

Olive oil is loaded with health benefits, so it’s no wonder it’s one of the staples of the Mediterranean diet. There are more than 1,200 search results on olive oil and cancer on PubMed.

Best Evidence: A meta-analysis of 45 studies published in 2022 found that people who consume olive oil daily have a 31 percent lower risk of any cancer compared to those who consume olive oil less frequently.

Swapping out other oils in your diet for olive oil is a simple way to take advantage of its health benefits. You can drizzle it over salads and cooked vegetables, or try using it in your marinades for meat, fish or poultry.

Though these studies show that there may be an association between olive oil intake and cancer, there are likely other factors involved as well. More human studies are needed to look at the direct effects of olive oil on cancer in people.

3. Dietary Fibers

Best evidence: A 2023 umbrella review (more than 100 studies analysed) of the literature indicated that a high intake of dietary fiber is associated with a reduced risk of several types of cancer, including esophageal, gastric, colon, rectal, colorectal adenoma, breast, endometrial, ovarian, renal cell, prostate, and pancreatic cancers. Conclusions: Dietary fiber intake has different protective effects on different cancers.

4. Citrus Fruits

Eating citrus fruits such as lemons, limes, grapefruits and oranges has also been associated with a lower risk of cancer in some studies. There are more than 18,000 research studies on fruits and cancer.

One large study found that participants who ate a higher amount of citrus fruits had a lower risk of developing cancers of the digestive and upper respiratory tracts (Source).

A review looking at nine studies also found that a greater intake of citrus fruits was linked to a reduced risk of pancreatic cancer (Source).

Finally, another review of 14 studies showed that a high intake, or at least three servings per week, of citrus fruit reduced the risk of stomach cancer by 28% (Source).

These studies suggest that including a few servings of citrus fruits in your diet each week may lower your risk of developing certain types of cancer.

Keep in mind that these studies don’t account for other factors that may be involved. More studies are needed on how citrus fruits specifically affect cancer development.

5. Nuts

Research has found that eating nuts may be linked to a lower risk of certain types of cancer. There are more than 1,000 search results on nuts and cancer on PubMed.

For instance, a study looked at the diets of 19,386 people and found that eating a greater amount of nuts was associated with a decreased risk of dying from cancer (Br J Nutr. 2015).

Another 2015 study followed 30,708 participants for up to 30 years and found that eating nuts regularly was associated with a decreased risk of colorectal, pancreatic and endometrial cancers (Source).

Another meta-analysis of 14 cohort studies (2015), found that dietary legume consumption reduces risk of colorectal cancer. Legumes are a diverse group of foods, including soybeans, peas, beans, lentils, peanuts, and other podded plants, which are widely cultivated and consumed.

Other studies have found that specific types of nuts may be linked to a lower cancer risk. For example, Brazil nuts are high in selenium, which may help protect against lung cancer in those with a low selenium status (Source).

These results suggest that adding a serving of nuts to your diet each day may reduce your risk of developing cancer in the future.

Still, more studies in humans are needed to determine whether nuts are responsible for this association, or whether other factors are involved.

Caution: Whilst we don't want to avoid nuts unnecessarily, limiting nuts may be helpful if you are experiencing recurrent cold sore (Herpes type 1) infections. While nuts are usually a great way to add to a healthy diet in order to pack in some extra protein, fibre and minerals, they are also a high source of arginine. In particular, peanuts, walnuts and hazelnuts are the worst offenders so steer clear of these. This includes peanut butter and other nut butters, unfortunately. (source)

6. Dairy products, milk, calcium and wholegrains

Best evidence: A 2021 umbrella review (Nature) of the literature concluded that consumption of dairy products, milk, calcium and wholegrains are inversely associated with colorectal cancer risk. Overall, 860 meta-analytic comparisons were included.

7. Soy

A review of 14 studies (Plos One. 2020) found that tofu intake was associated with a
lower risk of breast cancer. Tofu (bean curd), is a popular food derived from soy in Asia.

In another study, The Shanghai Breast Cancer Survival Study (JAMA. 2009), a large, population-based cohort study of 5,042 female breast cancer survivors. Over an average follow-up of 3.9 years, soy food consumption was significantly associated with lower risk of death and breast cancer recurrence.

A review of 35 studies (Plos One. 2014) found that soy intake could lower the risk of breast cancer for both pre- and post-menopausal women in Asian countries. However, for women in Western countries, pre- or post-menopausal, there is no evidence to suggest an association between intake of soy isoflavone and breast cancer.

8. Berries

Berries are high in anthocyanins, plant pigments that have antioxidant properties and may be associated with a reduced risk of cancer.

There are more than 17,000 search results on berries and cancer on PubMed. Do take note that most of the research studies are pre-clinical, lab, animal and non-human studies.

In one human study, 25 people with colorectal cancer were treated with bilberry extract for seven days, which was found to reduce the growth of cancer cells by 7% (Source).

Another small study gave freeze-dried black raspberries to patients with oral cancer and showed that it decreased levels of certain markers associated with cancer progression (Source).

One animal study found that giving rats freeze-dried black raspberries reduced esophageal tumor incidence by up to 54% and decreased the number of tumors by up to 62% (Source).

Similarly, another animal study showed that giving rats a berry extract was found to inhibit several biomarkers of cancer (Source).

Based on these findings, including a serving or two of berries in your diet each day may help inhibit the development of cancer. Keep in mind that these are animal and observational studies looking at the effects of a concentrated dose of berry extract, and more human research is needed.

That said, strawberries have remained in the No. 1 slot for several years in EWG's Dirty Dozen List 2023. Blueberries is one of the newcomers on the Dirty Dozen list for 2023.

The Shopper’s Guide represents EWG’s analysis of the latest fruit and vegetable testing data from the Department of Agriculture and Food and Drug Administration. The 2023 shopper’s guide includes data from 46,569 samples of 46 fruits and vegetables, revealing the presence of 251 different pesticides in total, including some that have already been banned due to their potential health effects.

9. Beans

Beans are high in fiber, which some studies have found may help protect against colorectal cancer (Source, Source, Source).

One study followed 1,905 people with a history of colorectal tumors, and found that those who consumed more cooked, dried beans tended to have a decreased risk of tumor recurrence (Source).

According to these results, eating a few servings of beans each week may increase your fiber intake and help lower the risk of developing cancer.

Vitamins, minerals and supplements (Micronutrients)

Supplement and cancer - An interesting and challenging topic. When it comes to vitamins and minerals it is confusing due to the many choices, claims and promises created by the healthcare supplement industry. While alluring claims and network marketing sell products, the products are not always suitable for cancer patients.

The body needs small amounts of vitamins and minerals to help it function properly. Most are found naturally in foods. Vitamins and minerals help the body use the energy (calories) found in foods.

A person who eats a balanced diet with enough calories and protein usually gets plenty of vitamins and minerals. But it can be hard to eat a balanced diet when you are being treated for cancer, especially if you have treatment side effects that last for a long time. In this case, your doctor or dietitian may suggest a daily multivitamin and mineral supplement.

If you are thinking of taking a vitamin or supplement, be sure to discuss this with your doctor first. Some people with cancer take large amounts of vitamins, minerals, and other dietary supplements to try to boost their immune system or even destroy cancer cells. Vitamins and minerals alone are not sufficient to fight cancer. Remember, nutrition is not about vitamins and minerals but there are other important elements (e.g. protein, water etc.) as well.

Clinical trials on vitamins and minerals are expensive and funding is difficult from the private sector. One high-profile example is the Selenium and Vitamin E Cancer Prevention (SELECT) trial of a decade ago, which cost US$114 million and demonstrated no meaningful benefit. Exacerbating the problem is the lack of a strong business model: drug companies have little incentive to invest in trials of a product that is cheap and widely available.

Some of these substances can be harmful, especially when taken in large doses. In fact, large doses of some vitamins and minerals may make chemotherapy and radiation therapy less effective.

The term anti-cancer supplements can be a little misleading. Some supplements may help reduce a person’s risk of developing cancer or support the body during cancer treatment.

"Anti-cancer supplements" is a misleading term. Some supplements may help lower your risk of developing cancer (prevention) or support your body during treatment. However, there's no guaranteed cure or prevention. It's important to distinguish between these two concepts. Supplements with evidence for reducing cancer risk fall under prevention, while those that might help manage the disease or improve survival rates are considered supportive during treatment.

That said, here is a list of studies that have given hope to the cancer community:

1. Vitamin D3 and K2

Is vitamin D the most powerful anti cancer supplement? Vitamin D can absorb calcium and help the immune, muscle, and nervous systems function properly. There are more than 11,000 search results on vitamin D and cancer on PubMed.

A 2023 systematic review and meta-analysis of 14 RCTs (randomized controlled trials), published in Ageing Research Reviews (Kuznia 2023) found vitamin D3 supplementation reduced cancer mortality by 6%. This wasn’t considered statistically significant, but when only studies involving daily vitamin D intake were analyzed, cancer mortality dropped by a significant 12%.

In another 2023 meta-analysis, 116 randomised controlled trials were analysed. The meta-analysis concluded that vitamin D reduces lung cancer mortality. All-cause mortality is decreased in patients with COVID-19 and liver diseases, especially in liver cirrhosis.

A 2022 randomized-controlled trial (DO-HEALTH) trial to investigate the combination of three complementary treatments for the prevention of cancer and suggest that the combination of daily vitamin D3, supplemental marine omega-3s, and a simple home exercise program may be effective in the prevention of invasive cancer among generally healthy and active adults aged 70 and older.

Findings from a 3 year Randomized Controlled Trial with more than 2,000 participants observed a 61% reduction in the risk of invasive cancer among patients who completed a home exercise program and took vitamin D3 and omega-3 fatty acids daily. These results, from the DO-HEALTH trial (ClinicalTrials.gov identifier NCT01745263), were published in Frontiers in Aging 2022.

Dosage: Supplemental 2000 IU/day of vitamin D3, and/or 1 g/day of marine omega-3s, and/or a simple home strength exercise (SHEP) programme compared to placebo and control exercise.

A Secondary Analysis of the VITAL Randomized Clinical Trial studied the effect of Vitamin D3 Supplements on Development of Advanced Cancer. The Harvard research, published in the JAMA Network Open medical journal (2020), overturns the initial findings of a study of 25,000 people published in 2018.

Initially researchers believed there was no benefit from taking vitamin D, as they detected no reduced incidence of cancer diagnoses overall. But they were puzzled because cancer deaths went down among those taking the supplements. Meaning, there was no benefit in terms of prevention of cancer but a reduction in cancer deaths was observed.

A secondary analysis, found this anomaly can be explained by the fact that vitamin D seems to stop metastatic cancers - those aggressive types which spread to other parts of the body. That said, when stratified by BMI (body mass index), there was no significant reduction for the vitamin D arm in incident metastatic or fatal cancer among those with overweight or obesity (BMI 25-<30).

Many experts now recommend 800 to 1,000 IU a day, a goal that's nearly impossible to attain without taking a supplement. Although protection is far from proven, evidence suggests that vitamin D may help reduce the risk of prostate cancer, colon cancer, and other malignancies.

Although the role of vitamin D in cancer prevention remains an area of research interest and debate, avoiding deficient levels is recommended. (American Cancer Society 2020)

Dietary sources of Vitamin D include fatty fish, egg yolks, salmon, sardines, cod liver oil, some yogurt (read the label to see if it says "fortified with vitamin D"), some soy milk (read the label to see if it says "fortified with vitamin D") and fortified milk. Sun exposure is also another way to get vitamin D naturally.

Make sure to take 500 mg to 1000 mg of magnesium and 150 mcg of vitamin K2, (not K1) which are important cofactors for optimizing vitamin D function. And, remember the only way you know what your vitamin D level is, is to test it. Vitamin D level should be in a therapeutic range of 50 to 70 ng/ml for treatment of rheumatoid arthritis. Most people are shocked how low their level is when they finally get around to testing it.

That said, as researchers explained in Nutrients (2022):

“Vitamin D supplementation is not the magic pill that miraculously solves the cancer burden or that can replace a healthy lifestyle. It is necessary to foster a good environment and invigorate a healthy lifestyle, including a high-quality diet and physical activity. Both have been proven to confer health benefits in many diseases, including cancer, and are the best preventive measures available.”

Related: Vitamin D Level and Cancer: Vitamin D Reduces Cancer Deaths

Caution: The dosage for vitamin D in prevention (1,000 to 2,000 IU daily) is very much different from the high dose treatment dosage i.e. 20,000 to 50,000 IU daily. Always consult your doctor first!

Interestingly, several studies have been done on vitamin K2 and certain types of cancer. Two clinical studies suggest that vitamin K2 reduces recurrence of liver cancer and increases survival times (Source, Source). Additionally, an observational study in 11,000 men found that a high vitamin K2 intake was linked to a 63% lower risk of advanced prostate cancer, whereas vitamin K1 had no effect (Source).

2. Vitamin C

PubMed has indexed more than 3,000 research studies on vitamin C and cancer and more than 5,000 studies on vitamin E and cancer.

2022 - An umbrella review* (Xu 2022) to assess the existing systematic reviews and meta-analyses for the association between vitamin C intake and multiple health outcomes; showed that vitamin C intake was associated with reduced risk of all-cause mortality, cardiovascular disease (CVD), oesophageal cancer, gastric cancer, cervical cancer and lung cancer with an increment of 50–100 mg per day.

Beneficial associations were also identified for respiratory, neurological, ophthalmologic, musculoskeletal, renal and dental outcomes. A total of 76 meta-analyses (51 papers) of randomised controlled trials and observational studies with 63 unique health outcomes were identified. Harmful associations were found for breast cancer and kidney stones for vitamin C supplement intake.

2022 - Obese women who took vitamin C and B6 at amounts that exceeded the recommended daily intake levels were associated with a lower risk of breast cancer, according to a five-year long South Korean cohort study. 40,432 women without a history of cancer at baseline were included in this study.

2022 - A meta-analysis to review the association between vitamins and brain cancer showed that intake of vitamin C, β-carotene, and folate can reduce the risk of brain cancer, while high serum α-tocopherol (vitamin E) concentration also has a protective effect on brain cancer.

A 2017 meta-analysis of 11 studies concluded that patients with lower concentrations of serum vitamin E (the vitamin E level in your blood) had a higher risk for colorectal cancer.

2020 - Vitamin E’s impact on lowering prostate cancer incidence has been demonstrated by two randomized controlled trials’ use of serum metabolomics analysis.

3. Turmeric (Curcumin)

Curcumin is one of the nutrients with the most evidence-based literature supporting its use against cancer. There are more than 7,000 search results on curcumin and cancer on PubMed and more than 50 clinical trials with curcumin, most of which are still ongoing. The spice turmeric can be extremely helpful when it comes to fighting cancer.

Interestingly, curcumin appears to be universally useful for just about every type of cancer (Arslan 2022), which is really odd since cancer consists of a wide variety of different molecular pathologies.

A review paper published in 2022, analysed 21 human studies. Sixteen out of 21 clinical trials were associated with the effectiveness of curcumin or turmeric on various types of cancer, and the other five clinical trials were related to the evaluation of the efficacy of curcumin or turmeric in relieving the side effects of cancer chemotherapy and radiotherapy. The emerging data from the clinical trials confirm that curcumin has the potential for cancer prevention and intervention.

Both curcuminoids and related turmeric products have been sanctioned by the U.S. Food and Drug Administration (FDA) as safe.

4. Fish Oil (Omega-3 Fatty Acids)

PubMed has indexed more than 3,000 research studies on Omega-3 and cancer. Most people use fish oil supplements to enhance the amount of omega-3’s in their diet.

The first randomized-controlled trial to investigate the combination of three complementary treatments for the prevention of cancer and suggest that the combination of daily vitamin D3, supplemental marine omega-3s, and a simple home exercise program may be effective in the prevention of invasive cancer among generally healthy and active adults aged 70 and older.

5. Magnesium and Molecular Hydrogen

PubMed has indexed more than 5,000 research studies on magnesium and cancer.

Magnesium and Colorectal Cancer

Several studies have demonstrated an association between high magnesium intake and reduced risk of colorectal cancer (CRC).

A case-control study evaluated 2204 subjects from the Tennessee Colorectal Polyp Study (2007), which demonstrated that increasing total magnesium intake was significantly associated with decreasing risk of CR.. The highest tertile of dietary magnesium intake (>298 mg/day) was significantly associated with reduced risk of CRC in an age-adjusted model.

A study of 140,601 postmenopausal women from the Women’s Health Initiative (2015) with an mean follow-up of 13 years demonstrated a significant reduction in CRC risk with the highest quintile of total magnesium intake compared with the lowest quintile of magnesium intake. The benefit was driven by colon cancer, with a trend for rectal cancer.

Magnesium and Pancreatic Cancer

A study of 66,806 subjects aged 50 to 76 at baseline from the Vitamins and Lifestyle cohort (Nature 2015) evaluated magnesium intake and the incidence of pancreatic cancer during a mean follow-up of 6.8 years. Subjects with magnesium intake below the recommended dietary allowance were more likely to develop pancreatic cancer, particularly in those whose intake was less than 75% of the recommended dietary allowance. In this study, a 100 mg/day decrease in magnesium intake resulted in a 24% increase in risk of pancreatic cancer.

Molecular Hydrogen and Cancer

There is little evidence to show that molecular hydrogen can reduce the risk of cancer.

However, in terms of cancer management or treatment, studies involving the effects of H2 on cancer were systematically reviewed. More than 600 articles related to molecular hydrogen and cancer were retrieved from Cochrane, PubMed and Google Scholar, and 27 articles were included for this systematic review (2023).

Based on the authors' analysis, "H2 plays a promising therapeutic role as an independent therapy as well as an adjuvant in combination therapy, resulting in an overall improvement in survivability, quality of life, blood parameters, and tumour reduction."

Although H2 has demonstrated significant anti-cancer effects, the underlying mechanisms have not yet been elucidated. Many studies have shown that H2 therapy can reduce oxidative stress. This, however, contradicts radiation therapy and chemotherapy, in which ROS (Reactive Oxygen Species) are required to induce apoptosis and combat cancer.

Related: Best Molecular Hydrogen Tablets

Note: Most Molecular Hydrogen tablets uses pure elemental magnesium as its carrier and provides you with approximately 80 mg of magnesium per tablet. So, you receive also highly bioavailable magnesium for a healthy brain, muscles, cells, kidneys, and heart.

6. Melatonin

PubMed has indexed more than 3,300 research studies on melatonin and cancer. Melatonin is one of the most important antioxidant molecules. In the human body — aside from having direct antioxidant effects — it also stimulates the synthesis of glutathione and other important antioxidants like superoxide dismutase and catalase.

Many people are not aware that only 5% of your body’s melatonin — which is also a potent anticancer agent — is produced in your pineal gland. The other 95% is produced inside your mitochondria — provided you get sufficient near infrared exposure which is typically from sun on your bare skin. This is why vitamin D is more than likely a biomarker for sun exposure, which is intricately involved in melatonin production. (R)

The Mediterranean Diet (MD) dietary pattern is also rich in antioxidants, such as melatonin. A systematic review published in Antioxidants (Elena 2023) showed high melatonin contents in MD-related foods, such as tomatoes, olive oil, red wine, beer, nuts, and vegetables. The consumption of specific MD foods increases melatonin levels and improves the antioxidant status in plasma.

Melatonin - Treatment

2022 - An umbrella review of meta-analyses based on randomized controlled trials (Pharmacological Research 2022):

"Survival at one year (P < 0.005) significantly increased with cancer patients."

2020 - A case series of 14 advanced cancer patients (Trends in Oncology 2020), treated with high dose (1,000 mg/day) of melatonin; achieved a disease control of 54% of the patients:

"Moreover, this preliminary study may also suggest that high dose melatonin has no toxicity in cancer patients with poor clinical status, as well as in healthy subjects."

2005 - A systematic review of 10 randomized controlled trials (J Pineal Res 2005):

"All trials included solid tumor cancers. All trials were conducted at the same hospital network, and were unblinded. Melatonin reduced the risk of death at 1 yr (relative risk: 0.66). Effects were consistent across melatonin dose, and type of cancer. No severe adverse events were reported. The substantial reduction in risk of death, low adverse events reported and low costs related to this intervention suggest great potential for melatonin in treating cancer."

7. Zinc and Cancer

PubMed has indexed more than 20,000 research studies on zinc and cancer. Zinc is the second most abundant trace element after iron.

Given the important role of zinc in a wide range of enzymatic reactions and physiological processes, zinc deficiency has been identified in a variety of diseases, notably cancer. In recent years, multiple meta-analyses and reviews looking at zinc levels in individual cancer types have been published, as have a plethora of primary studies demonstrating a link between low zinc levels and specific types of cancer.

In a 2023 review, the authors summarize recent evidence implicating low zinc concentrations in serum or tissues as a characteristic in a wide range of cancers.

Additionally, a 2022 mini-review by Iqbal et al noted limited evidence for a correlation between high dietary intake of zinc and a reduced risk of breast cancer, suggesting that dietary supplementation could decrease the chance of developing this malignancy. These preliminary studies suggest that there could be potential for using zinc supplementation in the clinical setting to help prevent cancer development.

On the basis of the correlation between low zinc levels and poor cancer outcomes, many authors have speculated that zinc supplementation could be used to reduce the risk of developing cancer. A retrospective analysis published by Hosui et al. in 2018 reported that zinc supplementation appears to maintain liver function and decrease the risk of developing hepatocellular carcinoma. A more recent study by the same group found that oral zinc supplementation decreased the risk of hepatocellular carcinoma development in patients who received direct-acting antivirals to eradicate HCV [Hosui et al. 2021]. Valenzano et al. in 2021 also reported that in Barrett’s esophagus, administration of zinc gluconate resulted in the upregulation of several tumor-suppressive miRNAs and downregulation of inflammation-inducing proteins.

The extensive evidence demonstrating the prevalence of zinc deficiency in a wide range of cancer types suggests that zinc deficiency should be considered a relatively widespread feature of multiple cancers. While research regarding the potential clinical utility of testing zinc levels in patients with or at risk of developing cancer is still preliminary, the data suggest that zinc deficiency may be a potential biomarker for identifying patients at risk of developing cancer, predicting outcomes in patients with cancer, and even as a preventive or adjunctive treatment for cancer.

8. Green Tea (EGCG)

PubMed has indexed more than 2,000 research studies on EGCG and cancer. The Minnesota Green Tea Trial (MGTT. 2015) is the largest and longest double-blind, placebo-controlled, randomized intervention study that specifically evaluated the effects of oral GTE (green tea extract) containing defined quantities of EGCG on established biomarkers of breast cancer risk.

They randomized and stratified 1075 healthy postmenopausal women at high risk of breast cancer according to their breast tissue density and catechol-O-methyltransferase genotypes and divided them into two groups: 537 placebo and 538 green tea groups. Green tea group participants took 4 capsules that contained 843 mg EGCG, whereas the placebo group took capsules without green tea extracts.

Researchers measured changes in percent mammographic density, circulating endogenous sex hormones, and proteins of the insulin-like growth factor axis. Their results showed that supplementation with green tea extract could modify and reduce mammographic density (MD) and protect against breast cancer, even though it was only significant in younger women (50–55 years) and had no effect in older women (R), an age-dependent effect similar to those of tamoxifen.

According to a 2018 review, EGCG and green tea extracts may help prevent or delay cancer onset, cancer recurrence, and secondary growths from cancer.

9. Coffee and Cancer

PubMed has indexed more than 2,500 research studies on coffee and cancer.

Best evidence: A 2021 umbrella review (Nature) of the literature concluded that coffee consumption is inversely associated with risk of liver cancer and skin basal cell carcinoma.

In addition, based on data from a large observational study nested in a clinical trial, are in line with earlier studies showing a connection between regular coffee consumption and improved outcomes in patients with non-metastatic colorectal cancer. The study is being published by JAMA Oncology (2020).

According to a 2019 systematic review of four studies, coffee has a weak to strong inverse association with liver cancer. The researchers concluded that the Japanese population was likely to experience a decrease in the risk of primary liver cancer due to coffee consumption.

10. Quercetin

PubMed has indexed more than 4,000 research studies on quercetin and cancer. The safety and potential usefulness of quercetin for the prevention and treatment of cancer have been documented in both animal experiments and a phase I clinical trial.

2022 - A paper published in August 2022 in Nutrition Research analyzed the pro-apoptotic effect that quercetin has on aging cells. The paper reviewed preclinical and early phase data using quercetin as a senolytic agent and found the data showed it was effective in “preventing or alleviating cancer formation.”

The authors reviewed the importance of cellular aging in the development of cancer cells and the effect that quercetin may have on the suppression of cancer cell proliferation.

Cellular senescence is a dynamic and multi-step process that is associated with alterations in metabolic activity and gene expression. This can compromise tissue regeneration and contribute to aging. On the other hand, by removing senescent cells, age-related dysfunction can be attenuated and potentially extend the lifespan.

According to Mount Sinai, quercetin should be used with caution as it may interact with certain antibiotics by reducing the effectiveness of the drug. It may also enhance the effect of some blood thinners, which can increase your risk of bleeding. In addition to these, it may interact with corticosteroids, digoxin, cyclosporine and fluoroquinolones.

11. Gut Microbes and Probiotics

Not only have gut bacteria been shown to influence gene expression,(R, R) turning some genes on and others off, research (R) published in 2018 found gut microbes actually control antitumor immune responses in your liver, and that antibiotics can alter the composition of immune cells in your liver, triggering tumor growth.

Harvard Medical School researchers have identified the specific population of gut microbes that modulates both localized and systemic immune response to ward off viral invaders.

Certain gut bacteria also promote inflammation, which is an underlying factor in virtually all cancers, whereas other bacteria quell it. The presence of certain gut bacteria has even been shown to boost the patient's response to anticancer drugs. (Nature 2018)

One way in which gut bacteria improve the effectiveness of cancer treatment is by activating your immune system and allowing it to function more efficiently. Researchers have actually found that when these specific microbes are absent, certain anticancer drugs may not work at all.

Can antioxidant supplements help prevent cancer?

To update its 2014 recommendation, the US Preventive Services Task Force (USPSTF) commissioned a review of the evidence on the efficacy of supplementation with single nutrients, functionally related nutrient pairs, or multivitamins for reducing the risk of cardiovascular disease, cancer, and mortality in the general adult population, as well as the harms of supplementation. According to the recommendation, the USPSTF recommends against the use of beta carotene or vitamin E supplements for the prevention of cardiovascular disease or cancer. (JAMA 2022)

It is possible that the lack of benefit in clinical studies can be explained by differences in the effects of the tested antioxidants when they are consumed as purified chemicals as opposed to when they are consumed in foods, which contain complex mixtures of antioxidants, vitamins, and minerals (Source).

Therefore, acquiring a more complete understanding of the antioxidant content of individual foods, how the various antioxidants and other substances in foods interact with one another, and factors that influence the uptake and distribution of food-derived antioxidants in the body are active areas of ongoing cancer prevention research.

If you want to take in more antioxidants, health experts recommend eating a variety of fruits and vegetables, which are good sources of antioxidants. Taking large doses of antioxidant supplements or vitamin-enhanced foods or liquids is usually not recommended while getting chemo or radiation therapy. Talk with your doctor to find out the best time to take antioxidant supplements.

Related: Best Antioxidant Supplements 2024

Safety considerations for nutrition, supplements and cancer

Many people believe that if they find a pill or supplement in stores, it is safe and it works. Remember, a 'natural' product does not mean its a 'safe product. Some poisons are also natural but they are certainly not safe.

The US Food and Drug Administration (FDA) put out rules in 2007 to help ensure that supplements contain what their labels claim they do, but the supplement’s safety and its effects on the body are not addressed by any FDA rules. The FDA does not make manufacturers of these products print possible side effects on their labels. And the FDA cannot pull a dietary supplement or herbal product from the market unless it can prove that the product is unsafe. Stop taking the product and call your doctor right away if you have side effects, like wheezing, itching, numbness, or tingling in your limbs.

Tell your health care team about any over-the-counter products or supplements you are using or are thinking about using. Take the bottle(s) to your doctor to talk about the dose, and be sure that the ingredients do not interfere with your health or cancer treatments.

Stay away from Carcinogens

Many people worry that substances or exposures in their environment may cause cancer. As part of the American Cancer Society's role in informing and educating people about cancer and its possible causes, this document provides lists of substances and exposures that are known or suspected to cause cancer. The lists below have been developed by two highly respected agencies – the International Agency for Research on Cancer (IARC) and the US National Toxicology Program (NTP). Some related information is included on how these and other agencies and groups test and classify possible carcinogens. Read more here: List of Human Carcinogens

Heavy exposure at work to certain pesticides, dyes, and chemicals may increase the risk of getting cancer of the pancreas. Steve Jobs passed away due to pancreatic cancer. Though this may not be directly related to his pancreatic cancer, Steve confirmed his drug use (marijuana and LSD) during college days. Read more here: FBI-reports-Steve-Jobs-did-LSD. Many researchers agree that marijuana smoke contains known carcinogens, or chemicals that can cause cancer much like those in tobacco smoke. Read more here: marijuana and cancer.

Reduce Stress

While eliminating stress entirely might be unrealistic, understanding its impact on cancer progression is crucial. Chronic stress weakens our immune system, the body's natural defense against illness, including cancer.

The body responds to stress by releasing stress hormones, such as epinephrine (also called adrenaline) and cortisol (also called hydrocortisone). The body produces these stress hormones to help a person react to a situation with more speed and strength. Stress hormones increase blood pressure, heart rate, and blood sugar levels. Small amounts of stress are believed to be beneficial, but chronic (persisting or progressing over a long period of time) high levels of stress are thought to be harmful.

Stress that is chronic can increase the risk of obesity, heart disease, depression, and various other illnesses. Stress also can lead to unhealthy behaviors, such as overeating, smoking, or abusing drugs or alcohol, that may affect cancer risk.

Some studies have indicated an indirect relationship between stress and certain types of virus-related growths. Evidence from both animal and human studies suggests that chronic stress weakens a person’s immune system, which in turn may affect the incidence of virus-associated cancers, such as Kaposi sarcoma and some lymphomas.

It is difficult to separate stress from other physical or emotional factors when examining cancer risk. For example, certain behaviors, such as smoking and using alcohol, and biological factors, such as growing older, becoming overweight, and having a family history of cancer, are common risk factors for cancer.

Studies have shown that stress might promote cancer indirectly by weakening the immune system's anti-tumor defense or by encouraging new tumor-feeding blood vessels to form. But a study published in The Journal of Clinical Investigation (2010) shows that stress hormones, such as adrenaline, can directly support tumor growth and spread.

Sleep

Many studies, especially in the last 10 years, have evaluated the association between different types of cancer and different types of sleep disorders (Mogavero 2021). The majority of sleep disorders in patients with cancer are associated with activation of the inflammatory response (Mogavero 2021).

Circadian rhythm disorders seem to represent a risk factor for gastrointestinal and breast cancer, squamous cell carcinoma, thyroid and prostate cancer (albeit with dubious evidence), lymphomas and chronic myeloid leukemia, not for ovarian cancer. Insomnia represents a risk factor for a wide range of tumors, especially breast, nose, trachea, liver and oral cavity. (Mogavero 2021)

In a 2022 study, the detrimental associations of poor sleep with all-cause and cause-specific mortality risks are exacerbated by low PA (physical activity), suggesting likely synergistic effects. The study supports the need to target both behaviours in research and clinical practice.

A 2023 study indicated that insomnia and nap during the day may be risk factors of PLC (primary liver cancer) and adequate night sleep might keep us away from PLC (primary liver cancer).

A 2021 study, concluded that both unfavorable sleep duration and evening chronotype were associated with increased lung cancer incidence, especially for those with low to moderate genetic risk. These results indicate that sleep behaviors as modifiable risk factors may have potential implications for lung cancer risk.

Another similar study, the authors concluded that they have found robust evidence for effect of sleeplessness on lung cancer risk.

Key Takeaways

Although this is a comprehensive guide, please do not consider this guide as personal medical advice, but as a recommendation for use with professional providers. Consult with your doctor and discuss with her/him.
Our aim here isn't to replace your doctors' advice. It is intended as a sharing of knowledge and information. Do take note that most strategies are not 100% protective against cancer. It's a continuous struggle between the immune system and the cancer cells.
Cancer prevention should be part of a multi-modal approach in order to provide the best possible outcome. The above Diet and lifestyle recommendations are proven methods to reduce your cancer risk. That said, there is no miracle diet or treatment that can prevent all cancers.
You could also complement your research and read more from the American Cancer Society site. The site has comprehensive information on cancer. You could read more on cancer prevention by cancer type here: http://www.cancer.gov/cancertopics/prevention

The FLCCC has provided a summary protocol of the key interventions (in order of priority) you can take in order to prevent cancer (Chapter 3: ROLE OF REPURPOSED DRUGS AND METABOLIC INTERVENTIONS IN TREATING CANCER):

Quit smoking.
Reduce or limit the use of alcohol.
Lose weight: adopt a healthy diet, manage insulin resistance, and follow a time-restricted eating plan. OneDayMD view: If you have cancer and you are under weight, this is not for you.
Avoid processed food and processed vegetable oils.
Avoid sugary beverages and pure fruit juices.
Limit consumption of red meat to no more than 3 portions/week.
Vitamin D3: 5000 u/day and adjusted according to vitamin D3 level.
Omega 3 fatty acids: 2-4 g/day.
Green tea catechins: 500-1000 mg/day. Green tea extract should be taken during/after a meal, rather than on an empty stomach.
Melatonin: 0.75–5 mg (extended/slow release) at night.
Metformin: Metformin should be considered in anyone at high risk of cancer, whether their risk extends from diabetes, pre-diabetes, insulin resistance, chronic viral infection, smoking, or genetics. Requires doctor’s evaluation, approval, and prescription. (Suggested dose ranges from 250-2000 mg daily.) OneDayMD view: If you are not at 'high risk', stick to intervention no. 3.
Regular aerobic exercise and resistance training 30 minutes/day (walking, home strength training, etc.).
Reduce stress (meditation, yoga, mindfulness exercises, etc.).
Get at least 8 hours of high-quality sleep (ensure adequate sleep hygiene).
Avoid known carcinogens.

Cancer Care: The Role of Repurposed Drugs and Metabolic Interventions in Treating Cancer

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