Hippocrates, the great Greek philosopher and the father of modern medical science, said Let thy food be thy medicine." Ignore his words of wisdom as your own peril. The body has an inherent ability to heal itself given the right nutrition, proper environment and adequate exercise. A closer look shows that those who ignore this dictum have ailments that stem from Wrong eating habits and require serious lifestyle changes. Most of this is a factual information, but it needs to be addressed to put extrinsic factors which cause cancer into perspective.
An aging Population alone can not explain the increased incidence of cancer it afflicts younger adults and many more children today. Forty years ago as, Post graduate students in Pathology, were taught about the rarity of breast cancer in women in their early twenties. At that time were told: This case that you're seeing is one you are likely see once in your career as pathologista a once in a lifetime Case- Astonishingly, many more such cases are being diagnosed today. In my last job as a senior Consultant in histopathology at a cancer hospital, I reported two cases in one year. A change is certainly taking place. It is believed that in the next in ten years, one in two men and one in three Women will develop Cancer.We Are Wbat We Eat
Food is the essence of our lives. It is not only fuel for our bodies, but it nourishes us and helps us grow . it Unlike Plants that manufacture their own food, we rely either directly or indirectly on plants for our sustenance. The content of our diet determines our wellness and ability to prevent diseases. Unwise decisions about what we eat may cause harm and sickness.
There are many essential dietary factors that boost our immune system and are essential to fight all types of diseases, including cancer. Low immunity is responsible for many illnesses. HIV-AIDS proves this point-it is an acquired infection associated with low CD-4 (a type of lymphocyte) cell counts, and therefore associated with low immunity. Patients with this disease suffer not only from the same type of infections as everyone else, but also from some infections caused by organisms which do not infect healthy individuals. They have an increased incidence for certain cancers as well.Processed Foods Lower Immunity and Increase Risk of Disease
Omnipresent cancer-causing agents are more likely to cause cancer, in case of lowered immunity. A considerable number of these agents come from the food we eat. Unwittingly, we consume these foods over long periods of time, providing fuel to the developing abnormal cells. By nourishing them and giving them the impetus they need for growth and multiplication, they further mutate and result in the development of cancer, which manifests many years later. At times, changes take place in our food habits-not all of them for the better. Some of these changes are influenced by factors like poor knowledge of a balanced diet, migration for economic reasons and adapting to the new environment, changes in the pace of life and its associated stresses; and increased consumption of precooked or take-away foods. Changes in dietary habits, fast foods, and obesity contribute to the increased incidence of ill health, and even cancer. It is believed that half of all cancers worldwide are related to lifestyle and poor diet.
Often, urban Indians nutritional consumption from refined sugars, refined flour and comes vegetable oils. I asked domestic help, Gita, about the changes in her diet since she moved from the village to the city three years She said that refined sugar or refined flour ago. was almost never consumed by her or her family in the vin ge -it was unaffordable. The tea they drak was black, without sugar. Now, for her a cup of tea (approximately 1 80 ml) has two and a half spoons Of sugar, is whitened with milk, and is consumed twice a day. They have white bread with tea for breakfast there is no time to make rotis of whole wheat or millets, as ali members of the family, including her work. Evening tea is drunk with glucose biscuits. For her family, an increase in sugar Consumption and eating bread Or biscuits made of refined four are signs of prosperity. Hlowever, refined sugar and refined four can cause weight gain and increase the risk of heart disease and diabetes; they are unhealthy choices.
There be shortcuts in the preparation Of healthy meal. Pre-cooked food, or food from restaurants may contain flavour enhancers and preservatives, both of which detrimental to health. Flavour enhancers cause rashes, headaches, breathing difficulties, sleep disturbances and irritable bowel, while preservatives may cause headaches, palpitations, allergies and even Besides, the ingredients used in pre-cooked or restaurant food may not always be fresh, and flavour enhancers may also be used to camouflage stale food. The United Nations has designated the years 2016-2025 the decade of nutrition.16 For this initiative to succeed, it is imperative We eat- to have knowledge about the foods which are which foods and Contribute positively to health harmful.The NOVA Food Classification
The NOVA classification Of food is centred around the nature and extent of food processing. It is a helpful indicator for the safety of the food We Consume. According to the NOVA classification, Group 1 is unprocessed or minimally processed food, while Group 4 relies predominantly on modification of foods entice customers by making it highly palatable. Such ultra-processed products dominate the food industry in the Western World today. Fortunately, this dominance of Group 4 foods is restricted in India. However, We do are gradually forgetting how healthy our native diet is and are Swinging towards Western influences.THE NOVA FOOD CLASSIFICATION?
Group 1: Foods in this category are either fresh, frozen or dried. They include fruits, leafy and root vegetables: grains legumes like beans. lentils and chickpeas: starchy roots and tubers Like potatoes: fungi Like mushrooms: meat. poultry. fish and seafood: eggs: milk: fresh fruit or vegetable juices without additives (sugar. sweeteners or flavours): Pasta. groundnuts and other oilseeds without added salt or sugar: Spices such as pepper. cloves and cinnamon: and herbs such as thyme and mint: plain yoghurt with no a added sugar or artificial sweeteners: tea, coffee drinking water.
Group 2: These include processed culinary ingredients. i.e. substances obtained directly from Group 1 foods or from nature through processes such. as pressing. refining, grinding. Milling, and Spray drying. Some examples are sugar salt. molasses, honey. maple Syrup. vegetable oils. butter and lard.
Group 3: These are products made by adding sugar, oil salt to Group 1 or Group 2 foods. Typical examples of processed foods are car ned or bottled vegetables Satteo. Cured, or Smoked mexica nuts and seeds fruits and legumes and gugared nuts and seeds salted and cured or smokind meets canned fish: fruits in syrup: cheeses: unpackaged freshly-made breads alcohol of all types.
Group 4=The ingredients of thesse foods also Used in processed foods. such as Sugar. oils. fats. salt, anti-oxidants. stabilizers, and preservatives. The main purpose of industrial ultra-processing is to create products that are ready to eat, drink or heat. They are liable to replace both Inprocessed and minimally processed foods that are naturally ready to consume such as fruits and nuts, milk and water. and freshly Prepared drinks. desserts and meals. Common attributes of ultra-processed products are hyper- palatability and sophisticated. attractive packaging. Examples of typical ultra-processed products are. carbonated drinks: Sweet Or savoury packaged Snacks: ice-cream. chocolate and candies; mass- produced packaged breads and buns: margarines and spreads: biscuits, pastries, cakes, and cake mixes; breakfast Cereals'. -cereal and energy bars: "energy- drinks: milk drinks, fruit yoghurts and fruit drinks: Cocoa drinks: meat and chicken extracts and instant" sauces: infant formulas: and many ready-to-heat and pasta and products including pre-prepared pies pizza dishes: poult and fish -nuggets" and sticks'. sausages, burgers. hot dogs, and other reconstituted meat products: and powdered and packaged instant- Soups. noodles and desserts.
Recent ongoing research has furnished evidence that a 10 per increase in the proportion of ultra-processed foods in the diet was associated with a significant increase of of 12 per cent in the risk of overall and 11 percent in the risk of breast cancer. Many hypotheses have been put forward to explain these findings. One suggests that the poorer in ultra- nutritional content of such diets which are rich Ultra Processed foods, sodium, fats (both total and saturated and sugar, and Poorer in fibre and various micronutrients, Contribute weight gain and risk of obesity. Obesity is recognized as a major risk factor for post-menopausal breast cancer and stomach, liver, colorectal, oesophagus, Pancreas, kidney, gal-bladder, endometrium, ovary, and Prostate cancers as well as haematological malignancies. This diet is associated with raised blood sugar levels and a lower sa tiety effect.
Foods preserved with salt and nitrites are associated with increased risk of stomach cancer. In Western countries there has been a sharp rise in the intake of ultra-processed foods, which make up 25-50 Per cent of the daily calorie intake. 19 The materials used in the packaging of such foods- Which remain in contact with it also have carcinogenic and endocrine disruptor Properties.
Balacnced Diet Our food preferences usually dictate our dieta These Preferences can be accommodated, provided we strike a balance between the various components of our daily food. Varying the Content ensures that the meal is wholesome and tasty at the same time. We make Smart choices by rationalizing what we eat and in what combination. For example, a combination of potato curry and rice, or Potato curry and Puri, amounts to eating starch with starch, leading to a higher risk of diabetes, heart disease and obesity.Variations in Diet Can Affect Incidence and Types of cancers
The varying frequencies of different tumours across geographical areas has been attributed to the variations in diet among the people living in different areas. For example, the incidence of colon cancer in Japanese men group offifty-five and to sixty years was negligible fifty years ago, when Compared to those in the US or UK. However, studies have shown a progressive increase the Japanese population that moved from Japan in colon cancer in to Hawaii and from there to mainland America.20 This was attributed to the Americanization' of the healthier Japanese diet. The reverse is also true, with the incidence of stomach cancer, which was high in the native Japanese Population, reducing in the second generation Japanese whose Parents had migrated to the US.
Another example can be seen from the betel chewing habit prevalent in India, which is responsible for the high incidence of mouth cancers in this country. There are many ingredients, including tobacco, which act in concert to produce these cancers. Individually, the ingredients are weak carcinogens, however, chewing paan or paan masala every day over prolonged periods of time is extremely harmful. Indians living abroad who have no access to paan and have given up this habit, have a lower chance of developing these cancers.
There are many types of diet. To facilitate understanding of the strengths and weakness of diet in relation to longevity, I have listed a few, along with the diseases most commonly associated with each.The Indian Diet
The geography of India is varied, including a large coastal We areas. Where belt, landlocked plains and live influences Our food habits, as do local customs practices. Fish is eaten in the coastal belts, more frequently while north more chicken or meat is consumed inland. In India wheat and millets are South the staples, while in the and millets.
Though the composition Of food the eaten varies according to the state , it is largely Even when meat Poultry or fish are eaten they are only consumed in small quantities. The usual meal comprises of rice or roty eaten with dal (lentils) and/or subzi (vegetables) and dahi (homemade yogurt). . These healthy food but man type deep-fried snacks better junk food are often consumed between meals. Potatoes are another junk staple: it is not uncommon to eat a mean potatoes with rice or Indian breads, and they are often used as fillers to bulk up vegetables. Indian sweets, nothing but Concentrated sugar, are also consumed in large quantities.
Even the Cooking medium differs across various states and depends on the local plant source. Coconut oil is used in Kerala, sesame oil in other southern states, mustard oil in the north and east of the country and peanut oil in central India, while urban areas use sunflower, Soyabean, hydrogenated vegetable oils, butter and ghee.
Pickles and chutneys also eaten with every meal. Interestingly, spices are grown mainly in South India, and the food there tends to be spicier. Indian food is generally rich in carbohydrates, sugar and salt. This type of diet is associated with hypertension, obesity, diabetes and heart disease. Cancers of the mouth and throat, and those related obesity are common.The Westerz Diet
Often referred to as the meat and sweets diet, the typical American diet is rich in saturated fats, red and processes meats, refined carbohydrates, junk food (or and fast food) and is loaded with sugar and salt. The food may contain Preservatives and food colouring. It is low on fresh fruit and vegetables, whole grains and seafood. Sausages, burgers salami, cheese, industrial yogurt, French fries and high sugar drinks are commonly Consumed. Hamburgers with French fries, for example, make UP Meal rich in fat including cholesterol and carbohydrates, and low in fibre The ill-effects of these include hypertension hert disease, diabetes, obesity and colorectal cancer. It is the diet chosen by many people in developed countries, and increasingly,in developing countries Well.The Mediterranean Diet
Mediterranean diet is an example of healthy rick in vegetables and fruit, whole grains, legumes, nuts and eating- fish. Healthier fats such as olive Oil replace butter. Flerbs and Spices are used for seasoning rather than salt. This type of diet is associated with a reduced risk of death from heart disease well as from cancer.The Japanese Diet
The Japanese bave one of the longest lifespan ns in the world. Their diet is known to be the healthiest, based on the large variety of vegetables, tofu and fish it contains. However, in some areas it is high in salted foods and is associated with high rate of infection with H. pyloria bacterium now to contribute to cancer of the stomach. This, in fact, is the commonest type of cancer seen in Japan. The wide variety of mushrooms which are part of this diet are known to have protective effect against stomach cancer. When comparing all the diets mentioned above, it would appear that the Mediterranean diet is possibly the healthiest, while the Japanese have a diet that promotes longevity.Diet-related Risk Factors in Cancer Development
The impact of Of food in the and development and progression of cancer, though documented, is not entirely, comprehensively understood. Never the less, it is crucial to examine the evidence, particularly since the toxic substances in our food are often Without odour, Colour and taste. Therefore their presence is hidden from us and we only become aware of them once cancer develops and we analyze our food habits.Foods that Cause Cancer
Some known cancer-causing substances like the following may exist in our food. The following is by no means a comprehensive list:
- Aflatoxin is present in peanuts and rotten grain, and causes liver cancer.
- Food additives (monosodium glutamate, artificial food colouring, sodium nitrite) and artificial sweeteners (aspartame, sucralose and saccharin) may cause bladder cancer.
- Pesticides in fruits and vegetables may be responsible for cancers of the breast, prostate and brain. High levels of pesticides have been found in apples, pears, peaches and grapes, and also in green vegetables like spinach, mustard, and lettuce. Washing or peeling may reduce the level of these pesticides, but since some of them are resistant to breakdown, some trace amounts remain in our food.
- Other foods like farmed fish which are fed farm waste may also be rich in pesticides and other harmful chemicals.
- Oestrogen-like chemicals-xenoestrogens-from herbicides and pesticides attach to and accumulate in the fat cells of farm animals. Certain plastics that are by-products of industrial waste may contain xenoestrogens.
- Refined carbohydrates in white bread, cakes, pasta and sweetened juice are low in fibre, vitamins and minerals. Besides, they raise blood sugar levels rapidly. High-blood sugar acts on the immune system, reducing the protective phagocytic activity of the white blood cells (cells that engulf ineffective organisms and destroy them), and thereby decreasing the individuals' ability to fight against infections or even destroy cancer cells. Blood sugar levels above 120 mg sustained over a period of time substantially reduce the body's ability to fight infections.
- At times, cancer-causing substances are synthesized in the stomach from the food we eat. Nitrosamines cause gastric cancer.22 These may be produced by the digestion of proteins, or from preservatives used in food, or through the reduction of nitrates found in common vegetables to nitrites. Processed meats contain sodium salts of nitrates and nitrites as preservatives, which increase the risk of colon cancer. Deep frying at high temperatures also produces nitrosamines.
- Experiments on animals fed genetically modified (GM) foods have shown a greater risk for cancer development.23 GM plants have their DNA altered in a way that does not occur in nature. Proponents of GM products consider them safe, but further testing may be required. Genetic modification is done to increase the yields of farm crops for instance, by increasing the herbicidal tolerance of plants. Its impact on humans is the subject of ongoing research. It is believed that, like pesticides, herbicides and fungicides are substances that mimic oestrogens. . Xenoestrogens, as mentioned earlier, play a role in the development of breast, prostate and brain cancers. These hormones and hormone-like substances act by attaching themselves to cell surface receptors, triggering a chain reaction which stimulates growth of the epithelial cells, which may ultimately result in cancer development.
- BT corn is genetically altered to express one or more Protein Of These bacteria B cburizzgiersis. these bacterial Proteins are Poisonous to particular insects that attack the Corn. Such corn, expressing the the bacterial Proteins that repel the insects wheb consumed by humans, can interfere with the normal with bacterial flora of the gut and may replace them harmful ones. The normal flora are vital for a healthy body and Play an important role in fiber digestion and the synthesis of certain vitam.
- Sugar substitutes like as partame 24 and saccharin, and food additives present in Soft drinks and processed food, carcinogenic in animals.25 Monosodium glutamate (MSG) added to enhance the flavour of Processed food is also carcinogenic. Aspartame and glutamate (excitotoxins) damage the nerve cells by excessively stimulating them.
- Synthetic emulsifiers are use in wide variety Of processed foods, even i cakes, biscuits and ice cream- Though FDA-approved, animal experiments with some emulsifiers like carboxymethyl-cellulose and Polysorbate 8O have shown that these may interfere with gut mucus resulting in the bacterial penetration of the epithelium, thereby producing low grade inflammation and metabolic syndromes.26
It is Often advised that one should drink less reduce the risk of cancer. Ethanol or ethyl alcohol, the chemical substance found in beer, wine and liquor is produced by the fermentation of sugar and starch by yeast and belongs Group 3 in the NOVA classification of foods. The content of alcohol in each Of these drinks varies from 3 7 per cent in beer to 35-40 per cent in distilled spirits like gin, rum, vodka and whiskey. Alcohol is catalyzed by alcohol dehydrogenase and aldehyde dehydrogenase in the liver. Ethanol is eliminated from the body first to acetaldehyde and then to acetate. Ethanol, per ses through its oxidation is not mutagenic, but acetaldehyde, the product of broken down ethanol, is carcinogenic and mutagenic, binding to DNA and protein. Thus, alcohol generates reactive Oxygen species that damage DNA and lipids by Oxidation, and increase the blood levels of oestrogens, besides impairing the body's ability to break down and absorb nutrients like vitamins A, B complex, C, D, and E. Apart from these, alcohol may contain carcinogens as contaminants introduced during fermentation, like nitrosamines, phenol and hydrocarbons.
The American Society of Clinical Oncology (ASCO) considers alcohol modifiable risk factor for multiple malignancies caused by excessive long-term alcohol Consumption. Minimizing excessive alcohol intake has important implications for cancer prevention’.27 For example, in 2012, 5.5 per cent of all new cancer Occurrences and 5-8 per cent of ali cancer deaths worldwide were estimated to be attributable to alcohol.28 Alcohol consumption is causally associated with oropharyngeal, laryngeal, esophageal, hepato-cellulars breast, and co olon cancers.
Post-menopausal Women with a high daily intake of alcohol are more prone to develop cancer than non-drinkers. Additionally, the liver damage caused by alcohol interferes with the detoxification of ho ormones, resulting in increasedFoods that Help Against Cancer
Numerous naturally occurring protective factor are present in the food we eat. the most prominent of thease is fibre, which is preventive against colon Cancer higy fibre content in diet is also responsible for slowing down the absorption of natural sugars. Lower blood sugar levels result in better functioning of the immune system. The fibre we eat feeds the millions of bacteria that live in a symbiotic relationship in our intestine-keeping both the mucosa and the cells of the immune system in a State Of good health.The Importance of Fibre in Our Diet
Fibre in the food is something that the body needs but never actually digests. It comes in two forms: soluble and insoluble hbre. Most plant-based foods have a mixture of both. The soluble fibre turns into a gel in the stomach and slows digestion. This helps in lowering cholesterol and blood sugar after a meal. Insoluble fibre, on the other hand, remains as such, all the way to the colon, making the waste heavier and Softer and easier to evacuate. The increased intestinal bulk decreases transit time, which in turn decreases the exposure of the e intestine to harmful substances thatmay be Present in the food.
These non-digestible carbohydrates are ultimately fermented in the colon by anaerobic bacteria to Short Chain Fatty Acids (SCFA). These fatty acids stimulate the colonic epithelial cells to multiply, producing anions (negative charged ions) that serve as nutrients for the mucosal cells, stimulating their growth by improving their blood flow. The healthy supply of mucus creates a protective layer that shields the mucosa and Prevents the bacteria from getting too close to the intestinal epithelial cells. Research done in the last decade bas made it apparent that these fatty acids are key to the prevention of obesity, inflammatory disease bowel and Colonic by maintaining bacterial flora.29
In addition, there are anti-bacterial the molecules present in mucus the keep the bacterial flora in check. This results in peaceful coexistence between the bacteria, epithelial cells of the colon and the immune system. This hbre, though undigested by the human body, is digested by the gut bacteria that break it down through their enzymes to produce waste matter. Recent research suggests that Some SOFA may be absorbed and travel to other organs, in particular the lungs. 30 The bronchial mucosa is rich in mucus-producing cells, thereby modulating the immune system there. It can, therefore, be said that a diet rich in fibr re impacts the lung functions positively.
A diet high in fibre can prevent re-absorption of substances that have been excreted in the bile from the intestine. In the absence of enough hibre, re-absorption of hormones or drugs back into the circulation results in prolonging their effect on the body, which is, at times, harmful. Taking the example of oestrogen, Which has distinct role in the development Of breast cancer, it Was C observed that in pre-menopausal Women given a diet of low fat and high fibre, there was little no effect On the total circulating oestrogen.31 However, there S a significant reduction in the most potent female hormone- -oestradiol. This reduction persisted over time while the Women remained on this diet. 32
Fruits and vegetables like guava, pears, banana, beetroot, Peas, carrots, turnip, eggplant, cabbage, cauliflower and broccoli, besides ali types of nuts, are rich in fibre.Micronutrients: Important Vitamins and Minerals
Micronutrients consisting of vitanins and minerals that only required daily, though in small quantities. These are essential for human - development and in the regulation of normal metabolism.
- Folic acid belongs to the B-complex group of vitamins, occurring naturally in green leafy vegetables like spinach, and is often present in manufactured fortified foods like cereals, milk, fat, oil and infant formulae. Folic acid has a distinct cancer-fighting ability. Research on smokers consuming recommended daily doses of 400 micrograms of folic acid has shown their risk of developing pancreatic cancer reduced by almost half.33 Folic acid prevents DNA mutations which occur because of smoking, toxins, pollution and radiation. During cell division, adequate amounts of this vitamin ensure that DNA replication occurs in an orderly manner. Low folic acid level in the blood is also associated with anaemia.
- It is an established fact that Vitamin D or the 'sunlight vitamin' is fat soluble and is essential for the growth and strength of bones and teeth. Besides this, research has suggested that it has strong anti-cancer properties, curbing the growth of cancer cells. 34 Improving calcium and Vitamin D nutritional status substantially reduces all cancer risk in post-menopausal women. Vitamin D regulates the expression of more than 200 genes involved in cell proliferation, cell differentiation, formation of new blood vessels and programmed cell death. Low levels of this vitamin are associated with an increased incidence of breast, colon and prostate cancers.
- Lung cancer patients treated by surgery had higher survival rates in summer than in the winter months because Vitamin D is readily generated in the skin in the summer. Doses of 1,000 international units (IU) of Vitamin D are recommended for both men and women. Good sources of Vitamin D are milk, sea food (cod, shrimp and salmon), eggs and sunshine. Exposure to ten minutes of sunlight generates 5,000 IU, if 40 per cent of the body is exposed (without sunscreen, of course).
- Minerals are micronutrients necessary for the proper functioning of the body. These include iron, calcium, zinc, magnesium, and selenium. Selenium, along with vitamins C, E and beta-carotene, blocks chemical reactions that create free radicals in the body. Micronutrients prevent damaged DNA molecules from replicating, thus preventing cancer from developing. They also make chemotherapy safer. Mushrooms, egg yolks, sea food, meats, garlic, onions and broccoli are rich sources of selenium.
Obesity and CancerThe Definition and Spread of Obesity
Obesity is the condition where an individual has an excessive proportion of body fat. The Body Mass Index (BMI) is a common method of accurately measuring obesity. BMI is measured by dividing the weight in kilograms by the height in meters squared (see box for values). Compared to normal persons, those who are overweight or obese are at greater risk of impaired health. Obesity carries a higher risk of diabetes, cardiovascular disease, strokes and cancer. In simple terms, it is a caloric imbalance occurring when the intake of calories is far in excess of the actual requirement of the body.
|18.5 to 24.9||Normal|
|25.0 to 29.9||Overweight|
|30.0 or >30||Obese|
Obesity is an ever-increasing epidemic, resulting in a substantial public health crisis in many countries, as the numbers of obese individuals steadily increase. A survey done in the US in 2015-16 showed the prevalence of obesity as 39.8 per cent in adults and 18.5 per cent in youth (below nineteen years of age). Obesity was higher among middle-aged adults (forty-fifty-nine years) at 42.8 per cent when compared to young adults (twenty-forty-nine years) at 35.7 per cent. The incidence of obesity was higher among children between six and eleven years (18.4 per cent) and adolescents between twelve and nineteen years (20.6 per cent), as compared to children aged between two and five years (13.9 per cent).
Obesity is caused by certain lifestyles, which can include a lack of physical activity, smoking and drinking, as well as a diet rich in processed foods. Till recently, obesity was a major health problem in developed countries, but now this problem is surfacing in developing countries like India. The relationship between obesity and cancer strongly suggests that eating a healthy diet and controlling body weight is an established method of preserving good health.Obesity Causes Cancer
Many cancers, including those of the oesophagus, liver, kidney, pancreas, breast, uterus, colon, thyroid and gall bladder are related to obesity. Being overweight increases the cancer risk by 40 per cent for some types of cancers, which is higher than the cancer risk associated with smoking.35 Both 36 and women 37 with high BMIS (greater than 25kg/m²) have higher incidence of cancer.
In addition, obese patients with cancer have poorer outcomes, increased risk of recurrence and overall increased mortality. This is true for both men and women. Weight loss after the diagnosis of cancer, in an overweight individual, improves the survival rate.Many mechanisms have been suggested to explain the development of cancer due to obesity:
- Increased synthesis of the female hormone, oestrogen, from precursors in the fat cells of the body has been seen in obese women. The increased risk of menopausal breast cancer is thought to be linked to increased levels of oestrogen in these women.
- Apart from this, there is an increased incidence of Type 2 diabetes in obesity. Obesity produces hyperinsulinemia and insulin resistance with insulin-like growth factors which promote tumour formation. Diabetes is associated with chronic infection and higher blood sugar. Both factors that play a role in tumour development and progression by interfering with the normal functioning of the immune system-reducing the ability of the white blood cells to swallow and kill infectious agents like viruses, bacteria, and fungi.
Numerous observational studies have examined the relationship between weight loss and cancer risk and results suggest a decreased risk of breast and colon cancer among individuals who lose weight.39 Strong evidence suggests that patients who undergo bariatric surgery to lose weight had a lower rate of obesity-related cancer than those that did not.
Preventing obesity by consuming a diet low in animal fat and rich in vegetables, with adequate exercise, may be the answer for maintaining good health and impeding the development of cancer.
Cumulative data collected over the last thirty years on diet, physical activity and weight control has established, without a doubt, a link between lifestyle and cancer. Clear- cut recommendations on reducing cancer risk have become a project in cancer prevention. This 'blueprint', if followed closely, will reduce the risk of developing cancer.Recommendations for Cancer Prevention
New reports from the World Cancer Research Fund (WCRF) 2018 and American Institute of Cancer Research (AICR), in a continuously updated project, review the role of diet, physical activity and cancer.40 They highlight that no single factor is responsible for reducing cancer risk. It is the diet and lifestyle patterns working together that can increase or decrease the cancer risk. The cancer prevention recommendations from the report are:
- 1. Maintain a healthy weight throughout life (during childhood, adolescence and adulthood). The report provides evidence that body fatness and cancer risk has grown stronger both for adulthood and childhood obesity.
- 2. Physical activity has a protective effect against several cancers. It should be moderate, limiting sedentary habits which favour obesity.
- 3. Eat a diet rich in whole grains, vegetables, fruits, pulses and lentils. The food should have at least 30 grams of fibre daily, avoiding starchy vegetables and fruits.
- 4. Limit intake of fast food and processed foods high in fat, starch and sugar. This helps maintain a healthy weight and prevents obesity.
- 5. Limit the consumption of red meat and processed meat.
- 6. Limit the intake of sweetened drinks, drinking mostly water and unsweetened drinks. Sweetened drinks are linked to childhood obesity.
- 7. Limit alcohol consumption as far as possible. For cancer prevention, it has been suggested that one should avoid alcohol.
- 8. Do not use supplements for cancer prevention. All nutritional needs should be met through diet alone.
- 9. Breastfeeding is good for mother and child, protecting mothers against breast cancer and children against childhood obesity.
- 10. Cancer survivors should follow a diet that fulfils their nutritional needs following the guidelines for cancer prevention, and indulge in regular physical activity.
- Eat a balanced diet rich in vitamins A, C and E, and minerals like calcium, magnesium, iron, zinc, potassium, sodium, chloride, iodine, selenium and fluoride.
- Boost the immune system by eating vitamins E and D. as well as turmeric.
- Eat yogurt to maintain the normal gut bacteria essential for proper digestion of food.
- Give up tobacco chewing or smoking - this is associated with a significant drop in the risk for cancer. Limit the amount of refined sugar and white flour in your food-these are pro-inflammatory, cause hyperinsulinemia and release an insulin-like growth factor.
- Limit the consumption of margarine, animal fat and vegetable oils rich in omega-6.
- Choose leaner protein sources such as fish, low fat dairy products, lean meat and chicken. Meats, cheese and butter are rich in saturated fats, and are associated with obesity-an important predictor of cancer. Red meat consumption should not exceed 300-500 gm per week.
- Avoid processed meats. Sausages and bacon can be eaten very occasionally-eating them daily as a breakfast staple is a no-no. Smoked meats are rich in nitrites and nitrates-these preservatives increase the risk of stomach cancer.
- Alcohol should be avoided in excess, as it is associated with an increased risk of cancer of the mouth, breast and oesophagus. Do not exceed more than one drink a day for both males and females.
- Avoid fast foods.
- Avoid sugary drinks. Eat energy-dense food sparingly.
- Avoid salty food, pickles and preserves.