Eating for cancer prevention
What role does diet play in cancer risk and prevention?
The Cancer Association of South Africa (CANSA) states that one quarter of South Africans are affected by cancer through diagnosis of family, friends or themselves. Over 100,000 South Africans diagnosed with cancer every year. 90% of cancers are caused by environmental and lifestyle factors.
Cancer Research UK says an unhealthy diet is linked to six types of cancer – mouth, upper throat, larynx, lung, stomach and bowel. Obesity ha been linked to cancers of the oesophagus, liver, upper stomach, gallbladder, pancreas, colon, breast (after menopause) endometrium, uterus, ovaries and kidneys.
Eating for better health
If unhealthy diets are linked with cancer, can the foods that we eat help to prevent cancer or lower our risk for contracting the disease? “Yes,” says Megan Pentz-Kluyts, consultant dietician to CANSA. “Diet and nutrition can either promote cancer or help prevent it. However, scientists need to conduct very large studies to see which specific foods protect us from cancer and which may cause it. For now, we know about the general types of foods that can help to keep us healthy and we know that a balanced diet will help to maintain a healthy body weight, which can in itself reduce the risk of developing many types of cancer.”
Include foods from these groups in your diet
Fruit and vegetables
“With fruit, aim for whole fruits with all the fibre. For vegetables, aim for fresh, frozen, dried or cooked (steamed or stir-fry),” says Pentz-Kluyts. “Aim for at least five servings of whole fruits and vegetables each day.”
Whole grains
“These are a major source of dietary fibre and contain germ, endosperm and bran, in contrast with refined grains which contain only the endosperm,” explains Pentz-Kluyts. “The germ and bran contain numerous nutrients which are removed during the refining process. In addition, whole grains are a major source of several vitamins, minerals, and phytochemicals, which have anti-cancer properties and could plausibly reduce the risk of colorectal cancer by several potential mechanisms. Whole grains are rich sources of fermentable carbohydrates, which are converted by the intestinal bacteria into short-chain fatty acids which help to protect against colon cancer in the gut. These fatty acids can reduce the activity of certain cancer-causing factors. Whole grain fibres also increase faecal bulk and bind carcinogens, which can then be speedily removed from the bowel before possibly causing health problems.”
Examples of whole grains include: whole wheat, wild rice, whole oats/oatmeal, buckwheat, corn on the cob, frozen whole kernel maize, brown rice, whole rye, triticale, bulgur (cracked wheat), millet, whole grain barley and sorghum.
Pulses (legumes)
Examples include lentils, peas and beans. Try to include legumes, pulses and soya products into dishes at least once to twice per week.
CANSA’s dietary guidelines:
- Eat three meals per day, with a snack between meals. Choose fruit and vegetables for snacks.
- Get more fibre – eat fruit and veggies with their skins on and whole grains as noted in the section above.
- Try to prepare at least one vegetarian meal per week.
- Attempt to include fish in your diet at least twice per week.
- Choose nuts, avocado and vegetable fats/oils like canola oil or olive oil. Choose Canola margarine products – it contains a good ratio of Omega 6 and 3 and is trans fat free
- Keep hydrated – drink plenty of safe, fresh water to help food move through the digestive system.
- Drink rooibos tea – it’s rich in antioxidants, low in tannin and caffeine free.
What to avoid – foods and food preparation
Megan Pentz-Kluyts provides that following guidelines:
- Restrict sugar and sugar-containing foods and drinks.
- Restrict salt.
- Eat dairy products and animal protein in moderation – choose hormone-free dairy products.
- Cut back on ‘braaing’ and do not deep-fry foods.
- Limit your intake of processed, cured and smoked foods such as biltong, bacon, polony, ham, russians and vienna sausages.
- Limit the intake of processed, refined and fast foods. Read the labels of processed foods like confectionaries for trans fat content. Legally, trans fats are restricted to less than 2%.
- Alcohol use is a cause of cancer so it’s best to avoid it in any form – beer, wine or distilled spirits. Any level of alcohol consumption increases the risk of developing an alcohol-related cancer. The level of risk increases in line with the level of consumption. There is strong evidence that alcohol causes cancer at seven sites in the body and probably others. The evidence supports ‘a causal association of alcohol consumption’ with cancer in the oropharynx (a part of the throat), the larynx, the oesophagus, the liver, the colon, the rectum and the female breast.
Please note: The information supplied is not meant to replace the advice of a medical professional. Please consult a registered dietician (RD) SA to help learn more about the best kinds of foods to eat as well as individualising your nutritional needs and diet. To find a dietician in your area, log on to
.
Other cancer prevention strategies
In addition to eating a healthy, balanced diet and cutting back on alcohol, consider the following cancer prevention strategies:
- Maintain a healthy body weight for your height throughout your adult life
- Stay active – or get active if you haven’t been exercising. Aim for at least 30 minutes of physical activity every day.
- Stop smoking
- Protect your skin from the damaging effects of the sun
- If you notice symptoms that concern you – such as a cut that doesn’t heal, a mole that changes shape or bleeds, a lump, changes in bowel habits, bleeding or weight loss – see your doctor.
Did you know?
Turmeric contains curcumin – one of the most potent antioxidants with anti-inflammatory, anti-cancer and anti-bacterial properties.
What is an antioxidant?
Antioxidants are chemicals that slow down or prevent the oxidation of other molecules. ‘Free radials’ are a by-product of the oxidation process. Too many free radicals in the system cause cell damage and contribute to aging. Antioxidants help to protect the brain and nervous system and guard against free radicals. Antioxidants are found in fruits, vegetables, wholegrains, nuts, legumes, dark chocolate and cinnamon.
Wholesome herbs and spices
Examples of health-promoting herbs and spices to include in your diet include garlic, oregano, sage, mint, rosemary, basil, thyme and tarragon. “Ensure that you use a reputable source for your herbs and spices,” says Megan Pentz-Kluyts.
Garlic
- immune-boosting
- contains antioxidants
Oregano
- fibre and vitamin A
- anti-inflammatory properties
Sage
- contains vitamin A and beta-carotene
- used to treat a number ailments
Mint
- high in antioxidants
- used to calm and soothe
Rosemary
- antioxidant and anti-inflammatory properties
- contains fibre, iron, calcium, vitamin A and vitamin C
Thyme
- stimulates appetite
- contains antibacterial properties
Tarragon
- bacteria-fighting properties
- natural sleep aid
Resources
- Cancer Association South Africa (CANSA), www.cansa.org.za
- The World Health Oranisation, www.who.org
- The National Health Service of the United Kingdom, www.nhs.uk
- MedScape, www.medscape.com
- World Cancer Research Fund International, www.wcrf.org