THE ROLE OF NUTRITION AND CANCER 2024

1. What is Cancer?

Cancer is a complex group of over 100 diseases. Cancer diseases share the common feature of uncontrolled spreading of malignant (harmful) cells in the human body. Under normal conditions, the cells in the human body divide and grow in an orderly, controlled manner. Cancer occurs when cells grow in an uncontrolled manner, losing its differentiation, invades local tissues and spreads.

2. How Does Cancer Kill?

Cancer cells grow rapidly and in an out-of-control manner. The cancer cells compete with normal cells for nutrients and even use up the body's energy reserves. When cancer grows, it steals nutrients from and starves the affected organ, releases toxins into that organ and renders the organ non-functional (2).

Haematological cancers such as leukaemia can deplete the immune system, so that a patient can die from viral or bacterial infections. Suppression platelet production can result in patients bleeding to death.

(2) Diamond, W et al. Definitive Guide To Cancer. Future medicine Publishing Inc. CA 1997

3. Risk Factors of Cancer

• Smoking
• Ultraviolet and Ionizing radiation
• Diet
• Family history
• Certain chemicals (e.g. asbestos)
• Hormones (e.g. diethylstilbesterol)
• Chromosomal abnormalities
• Chronic epithelial irritation
• Viruses

a. Diet

American Society for Cancer infers that a third of the cancer cases we see could have been avoided by a healthy diet and regular exercise (3). 

It has been suggested that animal proteins and saturated fata are linked to cancers of the colon, rectum, pancreas, kidney, breast, uterus and prostate (4). This is because animal fat and cholesterol when they are oxidized are toxic to cells.

Red meat is a confirmed cause of cancer. Red meat is high in cholesterol. Cholesterol is the precursor of hormones that could promote the growth of hormone-dependent cancers like breast and prostate cancer.

Women who ate a lot of red meat had double the rate of breast cancer compared to those who ate less meat. Likewise men who ate a lot of red meat had three times the rate of prostate cancer compared to those who did not.

(3) Byers, T&D et al. diet, Physical Activity and cancer...What's the connection? American Cancer Society. www.cancer.org

(4) Cancer Risk: Study On Chinese Here Bears Fruit. The Strait Times July 10 2003.

How to Prevent Dietary Related Cancer

1. Eat a healthy, balanced diet and with an increased intake of antioxidants.

2. Plant food is rich in antioxidants and essential for the fight against cancer. 

The Singapore Chinese Health Study, a landmark 10-year study of >60,000 people showed that eating green, leafy and cruciferous vegetables like kailan, choi sum, broccoli and cauliflower may reduce the risk of colon cancer and yellowish-orange fruits like papaya and tangerines may reduce the risk of lung cancer (5). Eat at least 5-8 servings of fruits and vegetables a day.

3. Limit fat intake especially saturated fat. Diets low in saturated fats have shown to lower colorectal and prostate cancer.

4. Avoid aged food (animal products) containing cholesterol or fats. Aged, stored, scrambled, mixed or whipped food contain increased amount of oxidized fat and cholesterol molecules.

(5) Vainio H, Bianchini F. IARC handbooks of cancer prevention. Volume 6: Weight control and physical activity. Lyon, France: IARC Press, 2002.

b. Obesity and Inactivity

Obesity and physical inactivity may account for 25 to 30 percent of several major cancers-colon, breast (postmenopausal), endometrial, kidney, and cancer of the esophagus (6). It is estimated that up to 16% of all cancer deaths are linked to excess weight.

The reverse is also true in that a 10% weight loss can result in 40-50% reduction obesity- related cancer death.

(6) Clinical Practice Guidelines on the Management of Obesity 2003; Malaysia Academy for the Study of Obesity.

Steps to prevent obesity-related cancer

1. Reduce weight with dietary means.

2. Exercise reduces body weight by burning up the calories and also promotes sweating to rid the body of accumulated cancerous toxins.

c. Smoking

Smokers account for 87% of lung cancer deaths. Lung cancer is the cause of 12.8% of cancer cases and 17.8% of cancer deaths worldwide(7). 

There are various carcinogens in the smoke such as tar and nicotine. Non-smoking women living with smoking spouses have 1.2 to 2 times the risk of developing lung cancer compared to women who live in smoke-free homes (8).

Tobacco smoke also suppresses natural killer cell activity that repels cancer, making smokers vulnerable to other cancers. Besides lung cancer, tobacco smoking is also a risk factor for other cancers such as oral cancer, esophageal cancer, laryngeal cancer, colorectal cancer, pancreatic cancer, cervical cancer stomach cancer, liver cancer, prostate cancer, bladder and kidney cancer (9).

(7) Parkin DM, Pisani P, Ferlay J. Global cancer statistics. CA Cancer J Clin 1999; 49: 33-64.

(8) American Thoracic Society. Cigarette smoking and health. Am J Respir Crit Care Med 1996; 153: 861-5.

(9) CancerHealthOnline - Cancer Information You Can Trust.

Steps to prevent tobacco related cancer

1. Quit smoking

2. Avoid secondary smoke

3. Take antioxidants and keep immune system strong

d. Viruses/bacteria

About 10-15% of cancer deaths could be linked to viruses. 

- Human Papillomavirus (HPV) is associated with cervical cancer, while up to 80% of liver cancers may be caused by Hepatitis B virus. 

- The Epstein-Barr Virus (EBV) is linked to nasopharyngeal cancers and lymphoma (cancer of the lymphatic system). 

- Helicobacter pylori, a bacteria that causes peptic ulcers is classified by the WHO as a Class I definitive carcinogen.

Steps to prevent pathogen related cancer

1. If at risk of stomach cancer (Le. family history or symptomatic), test for H. Pylori

2. Go for regular pap smear if sexually active. Also test for Human Papillomavirus (HPV).

e. Chronic stress

Stress is not just a mental state. The adrenal glands release cortisol which suppresses the immune system. This can lead to initial cancer cells going unchecked and proliferating.

Steps to prevent stress induced cancer

1. Identify stressor

2. Time management

3. Use acute stress stoppers such as breathing exercise, relaxation techniques etc

4. Avoid caffeine and alcohol

5. Herbs such as ginseng may be helpful

6. Take vitamin B-complex and immune boosting herbs such as propolis or echinacea

4. Signs & Symptoms of Cancer

Cancer is often missed, because the signs and symptom mimics closely to that of other less serious disease. The signs and symptoms of cancer depend on the site of cancer. Generally, patients manifest with progressive weight loss, anorexia and weakness.

If you experience any of the following signs and symptoms it is best not delay having a check-up.

• Change in bowel or bladder habits
• A sore that does not heal
• Unusual bleeding or discharge
• Thickening or lump in the breast or elsewhere
• Indigestion or difficulty in swallowing
• Obvious change in a wart or mole
• Nagging hoarseness
• Unexplained cough
• Sudden unexplained weight loss

5. Nutrition and Cancer Risk

Proper nutrition reduces the risk of numerous diseases, including certain cancers. There is a direct link between dietary choices and 30 to 40 percent of cancers.

Good nutrition involves eating a variety of healthful foods - especially fruits and vegetables, which are rich in antioxidants. These nutrients protect the body against the tissue damage that results from normal metabolism. Because this tissue damage is linked to increased cancer risk, antioxidant nutrients may play an important role in cancer prevention.

a. Obesity and Cancer

Poor nutrition and inactivity typically contribute to excess body weight and obesity, which, in turn increases an individual's risk of developing many types of cancer. 

In fact, an estimated 41,000 new cases of cancer in 2002 were believed to be caused by obesity, according to the National Cancer Institute (NCI). The relationship between obesity and cancer is not yet fully understood. 

However, obesity increases an individual's risk of developing the following types of cancer:

• Breast cancer (in postmenopausal women)
• Colorectal cancer
• Endometrial cancer
• Oesophageal cancer
• Gallbladder cancer
• Kidney cancer
• Pancreatic cancer
• Prostate cancer

b. Role of diet in cancer prevention

Eating a diet low in fat and high in fibre can reduce the risk of various diseases, including certain cancers. 

Many studies have suggested that specific nutrients can help prevent cancer. For example, lycopene (a pigment found in red fruits) and the mineral selenium may play a role in averting prostate cancer, according to the American Cancer Society (ACS). 

Since most research into diet cancer is preliminary, the ACS recommends that individuals consume a variety of healthful foods especially those derived from plant sources, which are packed with vitamins and fibre. 

c. Dietary guidelines for cancer prevention 

i. Eat at least five servings of fruits and vegetables each day

These foods are rich in antioxidant nutrients, which are believed to protect against cancer. Suggestions to achieve this guideline include:

• Consume a variety of fruits and vegetables.
• Include fruits and vegetables at every meal.
• Replace unhealthy snacks with fruits and vegetables.
• Prepare vegetables in a healthy manner (eg, limit consumption of fried potato chips and French fries).
• Drink only 100 percent fruit or vegetable juice.
• Choose whole grains instead of refined (processed) grains and sugars.
• Select whole-grain breads, pasta, rice and cereals.
• Limit consumption of carbohydrates that are refined, including white bread, soft drinks, sweetened cereals, pastries and sugars.
• Limit consumption of red meat, especially processed meats and those high in fat.
• Replace beef, lamb or pork with poultry, fish or beans.
• Select lean cuts of meat.
• Consume smaller portions of meat (less than 3 ounces a day).
• Prepare meat by baking, poaching or broiling instead of charbroiling or frying

ii. Select foods that help achieve and maintain a healthy weight

1. Choose foods low in calories, fat and sugar when dining out.

2. Avoid oversized portions, especially when dining out.

3. Consume smaller portions of foods that are high in calories. Individuals should be aware that foods labelled "low fat" or "fat free" often contain many calories.

4. Replace calorie-dense foods, such as pizza, curries and ice cream, with fruits, vegetables and other low-calorie items.

5. Limit the consumption of alcoholic beverages, one drink per day for women, two for men. 

The relationship between alcohol and cancer is not yet fully understood. Experts theorize that alcohol itself, or the way it is metabolized in the body, may have a carcinogenic effect. In addition, alcohol may increase certain hormone levels which are associated with a higher cancer risk.

iii. Limit salt intake

The National Cancer Institute (NCI) recommends that individuals limit salt intake and consume 35 grams of fibre a day. Fibre is found primarily in fruits, vegetables, whole grains and legumes. It helps prevent colorectal cancer, promotes weight loss, reduces cholesterol levels and offers other health benefits.

6. Nutrition During Cancer Treatment

Exercising proper nutrition is especially important for cancer patients. Many cancer patients have a decreased appetite and cannot tolerate certain foods. This can result in poorer intake and less nutritional support. In addition, cancer can impair the body's absorption of important nutrients (malabsorption). 

The various cancer treatments can also cause certain side effects that make eating difficult or painful. The type and severity of side effects depends upon a variety of factors including the type of cancer, the type of treatment, the length of treatment as well as other factors. 

a. Side Effects of Cancer Treatment That Affects Diet

• Sore or dry throat and mouth
• Gum or dental problems
• Difficulty swallowing (dysphagia)
• Change in taste or smell
• Nausea or vomiting
• Diarrhoea and constipation
• Fatigue
• Depression

Patients should speak with their physician about the eating-related side effects of specific treatments, and ways to counteract these problems. 

For instance, if a patient has trouble swallowing, the physician may recommend adding liquids that are thick in consistency, such as milkshakes, or soft foods such as mashed potatoes to the diet. 

If the patient often experiences nausea and/or vomiting, the physician may recommend adjusting the meal schedule to include longer periods between eating and treatment sessions, or smaller, more frequent meals.

b. Importance of Proper Nutrition During Cancer Treatment

The nutritional needs of people with cancer vary from patient to patient, and depend on factors such as the patient's size and age, and whether an individual has experienced significant weight loss (5 percent of total body weight or more) due to treatment. Patients should discuss their nutritional goals with their physician and/or dietician. 

Eating well during cancer therapy can help patients:

• Feel better
• Maintain their strength and energy
• Maintain their body weight
• Maintain their body's store of essential nutrients
• Tolerate side effects related to treatment
• Decrease their risk of infection

Proper nutrition may also speed up the healing and recovery time of some patients Eating well may also help some individuals in handling higher doses of cancer treatments. In addition, cancer patients who are well-nourished typically have a better prognosis (predicted outcome for survival).

c. Recommended Diet During Cancer Treatment

For cancer patients, eating well means consuming a variety of foods that provide the nutrients needed to help maintain their health while battling cancer. 

In general, cancer patients should strive to consume the following each day..

• Six servings of grains, preferably whole (unrefined)
• Three to five servings of vegetables
• Two to four servings of fruit
• Eight 8-ounce glasses of water

d. Nutritional Support Before Cancer Treatment

Many cancer patients seek nutritional support prior to beginning cancer treatment. 

Early nutrition screening and assessment can help to identify any problems that may impact the success of cancer therapy. Early discovery and treatment of nutrition problems may help a patient maintain a healthy weight and reduce some of the complications from treatment. Patients who are healthy typically respond better to cancer therapy.

e. Nutritional Therapy for Cancer Patients

Cancer patients who are unable to eat well because of treatment-related side effects may benefit from nutritional therapy. 

Nutritional therapy is designed to help patients in active treatment and recovery as well as those with advanced cancer. Goals of nutritional therapy may include preventing/correcting malnutrition, decreasing nutrition-related side effects, improving the patient's quality of life. 

• Nutritional therapy varies according to patient and treatment type, but may include..
• A specialized diet plan
• Nutritional supplement beverages
• Enteral nutrition (a short-term feeding tube inserted through the nose, down the throat and into the stomach, or a long-term tube surgically placed through the abdomen into the stomach or small intestine)
• Parenteral nutrition (an intravenous feeding tube)
• Appetite-improving medications

f. Roles of Each Nutrient During Cancer Treatment

Protein 

Protein helps to repair body tissue, maintain the immune system's health and ensure growth. With insufficient protein, the body's resistance to infection is reduced and recovery from illness may take longer. 

Therefore, cancer patients may require more protein than those without cancer. After surgery, radiation therapy or chemotherapy, extra protein is typically needed to mend tissues and help prevent infection. 

Good sources of protein include..

• Lean meat and poultry
• Fish
• Low-fat dairy products
• Nuts
• Dried beans, lentils and peas
• Soy foods
• Egg whites

Carbohydrates and fats

These nutrients supply the body with the majority of its caloric needs. The amount of calories a person needs depends on size, age and level of physical activity. 

Sources of carbohydrates include..

• Fruits
• Vegetables
• Pasta and breads
• Grains and cereals
• Dried beans, lentils and peas

Sources of fat include

• Seeds and nuts
• Butter, margarine and oils
• Cheeses and other fatty dairy products
• The fat in poultry, fish and meats
• Egg yolks

The U.S. Department of Agriculture's (USDA) revised food pyramid emphasizes that fats are not created equal. 

Fish oils and some vegetable oils, such as olive oil, have health benefits. The USDA recommends avoiding artery-clogging trans fats (such as partially hydrogenated vegetable shortening), saturated fats and cholesterol.

Vitamins and minerals

These nutrients are the basics for proper growth and development. They also enable the body to use the energy (calories) supplied in foods. 

Individuals who eat a balanced diet with sufficient calories and protein typically get enough vitamins and minerals. However, some side effects of cancer treatment can make eating a balanced diet very challenging. Therefore, physicians may recommend that patients who are undergoing cancer treatment take a daily multivitamin and mineral supplement.

Water

Water and other fluids are essential to good health. Individuals who do not consume enough water, or lose water due to vomiting or diarrhea can become dehydrated. Patients should drink water that is purified and clean.

7. Supplements To Fight Cancer

a. VITAMIN E

It has been shown in a study that Vitamin E is an excellent supplement that can help you to prevent cancer. Actually, Vitamin E is fat soluble that's why it acts as a strong antioxidant that helps the body to remove free radicals which actually cause damage to the cell.

Not only that but Vitamin E can decrease the risk of colon, prostate, and lung cancers. In fact, the Deficiency of Vitamin E may increase the risk of cancer.

Food with Vitamin E

Wheat Germ Oil, Sunflower Seeds, Almonds, Hazelnut Oil, Sunflower Oil, Almond Oil, Hazelna Wheat Germ Oil So Goose Meat, Peanuts, Atlantic Salmon, Avocado, Rain Products Red Swe Pepper (raw), Brazil Nuts, Mango, Turnip Greens (raw), Kiwifruit, Anyfish, Fish, Octofigh in Vitan E. Abalone, Goose Meat, Atlantic Salmon, Rainbow Trout, Snails, Crayfish, Fish, Octopus, Lobster Cod (dried), Seeds and Nuts High in Vitamin E, Sunflower Seeds, Almonds. Hazelnuts, Pine Nut Peanuts, Brazil Nuts.

b. VITAMIN D

Vitamin D is another important vitamin that helps in fighting certain types of cancers. 

Vitamin D helps the body in absorbing calcium and phosphorus which make bones and teeth stronger. Skin exposed to the sunshine makes Vitamin D. Deficiency of Vitamin D can weaken bones.

Some studies suggest that diseases like lung cancer, bowel cancer and breast cancer can have a higher rate of occurring if there is a deficiency of Vitamin D.

Food with Vitamin D

Tuna, mackerel, salmon, orange juice, soy milk, cereals, Beef liver, Fatty fish

c. CURCUMIN

Curcumin is found mainly in turmeric. Turmeric has been used for thousands of years in Asian countries like India and China due to its seamless medicinal benefits. It is rich in antioxidants and can be used to slow down or prevent the cancer process.

Some research suggests that curcumin, an important ingredient of turmeric may help prevent or treat cancer. There are so many research reports already available on the internet that claims curcumin can slow down cancer by protecting healthy cells from damage. It makes chemotherapy more effective.

Some common benefits of curcumin are that it blocks cancer cells from multiplying. It kills breast, colon, and prostate cancer cells. It also slows down tumour growth.

d. GREEN TEA EXTRACT

We all know about green tea's benefits when it comes to losing weight. Green tea is well known for improving metabolism and burning fat simultaneously. But do you know that green tea can also be very beneficial in the treatment of cancer? 

Green tea is rich in "polyphenols" a substance that has an anti-cancer effect. Polyphenols can induce the apoptosis process (tumour cell death). It also prevents the formation of blood vessels around the tumour.

It has been also shown in a study that one important polyphenol named "ECG" found in green tea also helps in stopping blood cancer cells (leukemic cells).

Since it is also an antioxidant green tea helps in repairing damaged cells and preventing free radicals damage. So what are you waiting for? Start consuming 2-3 cups of green tea every day.

e. RESVERATROL

You must have eaten grapes hundreds of thousands of times but do you know that the skin of grapes contains the very special nutrient resveratrol, which is very helpful in protecting against cancer? 

Resveratrol is a powerful antioxidant that is also classified as a polyphenol. It is directly associated with anti-aging also.

It has been shown in a study that resveratrol hinders nuclear factor Kappa beta (NF-KB), NF-KB is an inflammation-causing agent primarily responsible for promoting cancerous growth in tissues.

The polyphenols present in resveratrol inhibit NF-KB for the normal processes of the immune system. It also hinders HRB BETA 1, which is responsible for activating cancer growth in the breast. HRB BETA I is actually a pathway that gives signals to the cells to activate cancer growth. Resveratrol stops this pathway and prevents breast cancer.

Food with Resveratrol

Blueberries, cranberries, lingo berries, peanuts, and pistachios, red and purple grapes, mulberries.

f. OMEGA 3

Omega-3 fatty acids are actually a combination of 3 fatty acids which are Alpha-linoleic acid (ALA), Eicosapentaenoic acid (EPA), and Docosahexaenoic acid (DHA).

Alpha-linoleic acid is found mainly in oil derived from the plants such as Soya beans, canola flaxseed. Eicosapentaenoic acid and Docosahexaenoic acids are mainly found in fish and seafood

Omega 3 fatty acids are a great anti-inflammatory compound that's why it helps in many cancers linked to chronic inflammation, including liver, lung, and prostate. Omega 3 fatty acids are also known to help in reducing tumour cell growth.

Food with Omega 3

Flaxseed, fish, nuts

g. GLUTATHIONE (GSH)

Glutathione is the master detoxifier of each and every cell of our body. It is an important antioxidant that is present in our body. Glutathione plays a very crucial role in protecting healthy cells from radicles which can cause cancer. It has been proven in detoxifying and remove carcinogens. A low level of GSH makes you more vulnerable to cancer.

h. SELENIUM

Selenium is an antioxidant; therefore, it removes free radicals from the body. It also plays important role in recycling antioxidants throughout the body. 

Studies have shown that Selenium take can reduce the risk of cancer. It is known to protect against the harmful effect of mercury, cadmium, etc., and helps in eliminating cancer cells. Not only that but it also slows down tumour growth.

Food with Selenium

Ham, Pork, Beef, Turkey, Chicken, Enriched foods.

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Sources

2. Diamond, W et al. Definitive Guide To Cancer. Future medicine Publishing Inc.CA 1997.

3. Byers, T&D et al. diet, PhysicalActivity and cancer...What's the connection? American Cancer Society. www.cancer.org

4. Cancer Risk: Study On Chinese Here Bears Fruit. The Strait Times July 10 2003.

5. Vainio H, Bianchini F. IARC handbooks of cancer prevention. Volume 6: Weight control and physical activity. Lyon, France: IARC Press, 2002.

6. Clinical Practice Guidelines on the Management of Obesity 2003; Malaysia Academy for the Study of Obesity.

7. Parkin DM, Pisani P, Ferlay J. Global cancer statistics. CA Cancer J Clin 1999; 49: 33-64.

8. American Thoracic Society. Cigarette smoking and health. Am J Respir Crit Care Med 1996; 153: 861-5.

9. CancerHealthOnline - Cancer Information You Can Trust.