Did you know that what you eat can change your genetic expression? Welcome to the exciting new science of nutrigenomics, in which food scientists, doctors and nutritionists study how our genes interact with nutrients. The premise is that diet is a big causative factor in chronic disease: a possible reason why Asians are more prone to hypertension and heart disease. In nutrigenomics, it is also believed that diets are responsible for most types of cancers.
Various theories suggest that an out-of-balance diet can change our gene expressions and make us susceptible to chronic illness. The solution: Choose food that is appropriate to your genetic make-up. In fact, the examples nutritional scientists trot out in support of their theory certainly appear convincing. For instance, a study has concluded that the Japanese who relocated to the US after the second world war and adopted a Western diet, saw their cholesterol levels soar. Closer home, nutrition scientists claim that Indians are becoming increasingly prone to lifestyle diseases because we are shunning our traditional vegetarian menus and filling our plates with red meat and overprocessed food.
Antonia Trichopoulou, director, WHO Collaborating Centre for Nutrition, University of Athens, Greece, says the focus in the last 10 years has been on identifying a dietary pattern that maximizes longevity. According to her, it is undeniably the ‘Mediterranean diet’, or the ‘gift of god’ as she calls it. Trichopoulou, who was part of a team of food scientists, medical doctors and researchers from the Mediterranean region that visited India recently to promote their diet as the “model of good health”, says researchers have for long acknowledged it as one of the healthiest traditional diets in the world. The Mediterranean diet, she claims, protects your heart, deters cancer and boosts your body’s immunity.
Even the Japanese are fervently promoting their traditional diet. Daisuke Hutami of the Japan Dietetic Association in Tokyo says an increasing number of Americans, convinced that the reason for the longevity of the Japanese lies in their dietary pattern, are now copying their diet, which relies more on fish, rice and legumes such as soya beans.
Since the 1960s, when Prof. Ancel Keys, from the University of Minnesota School of Public Health, launched the Seven Countries Study, where he studied the effect of good health and dietary pattern, the Mediterranean and Japanese diets have emerged as front-runners in the global good health diet chart. Unfortunately, Prof. Keys’ study did not include the Indian diet.
However, interest in the traditional Indian diet is now increasing all over the world. A number of studies have concluded that apart from some positives, the modern-day Indian diet relies heavily on starchy food and has too much white sugar.
In comparison, however, nutritionists say our traditional menus were very healthy. Even the Oldways Preservation and Exchange Trust (www.oldwayspt.org), a food issues advocacy group, points out that regional Indian diets had a strong emphasis on whole grains and plant food, with only moderate amounts of animal products. New Delhi-based nutritionist Shikha Sharma and Mumbai-based health activist Vijaya Venkat suggest that it is time we returned to the ancient Ayurvedic diet that relied more on fruits and vegetables. K.T. Achaya, a food historian, in his book A Historical Companion to Indian Food says even the giants of Indian medicine, Charakha, Susruta and Vaghbata, stressed on the preservation of good health through a well-adjusted diet. He also points out that diets earlier were prescribed on the basis of vatha, pitha and kapha constitutions. The tamasic, sattvik and rajasic foods were also prescribed according to the person’s gunas.
In the light of the findings of modern-day nutrigenomics, clearly then it is time for a drastic change in our dietary pattern. But the question is that given the whole nutrigenomics theory, can Indians adapt to the Mediterranean diet? Research on Mediterranean diets in Australia, the US and even India has tried to find out whether the benefits of the Mediterranean diet are transferable to other populations. The verdict has been largely favourable. In fact, a study published a few years ago in British medical journal The Lancet, on the effect ofan Indo-Mediterranean diet on progression of coronary artery disease (CAD) in high-risk patients in India, did show its beneficial effect in primary and secondary prevention of CAD.
Given the strong tastes and cultural factors, diets continue to be a contentious issue. Especially as there have been too many theories and counter-theories.
Experts say it is not so much about switching to an alien diet, as about following the broad principles of this model—i.e. put more emphasis on fruits, vegetables and nuts, and understanding that fats from plant oils are not necessarily bad, especially if they are unsaturated, as olive oil is.
In the past, Indian food guidelines from the Indian Council of Medical Research (ICMR) followed the American model of putting a severe restriction on intake of oils. But now, the Americans themselves, after studying various Asian and Mediterranean models, are changing their food pyramid and guidelines, and allowing daily use of oil. Ultimately, some practical good sense is required, as New Delhi-based nutritionist Ishi Khosla sums up: “As our working and living habits evolve, it’s time to evolve our dietary habits too and go in for a platter that’s in consonance with our current day lifestyle, which is more sedentary.”
Let’s take a look at various global menus.
Almost 40% of the calories in a Mediterranean diet come from fat. However, the fat—which comes from olive oil and fish—is unsaturated.
The conclusion is that unsaturated fat is actually beneficial. So, banishing oils to the top of the chart, where the low consumption items are placed, is not necessarily a good way to make the food guide pyramid. The Mediterranean diet, which is not a specific diet plan but a collection of eating habits of people from this region, also includes a lot of red wine which, according to Trichopoulou, “along with olive oil has antioxidant polyphenols that inhibit endothelial activation” (endothelial activation is today thought to be responsible for several diseases such as artherosclerosis and cancer).
People in this region also consume a lot of legumes and nuts, as well as vegetables and fruits, and whole grains. According to Spanish physician Miguel A. Martinez Gonzalez from the Universidad de Navarra, Spain, adherence to the Mediterranean diet reduces the risk of diabetes and metabolic syndrome.
The “seven pillars of Japanese food” are fish, vegetables, rice, soya, noodles, tea and fruit. New Delhi-based nutritionist Ishi Khosla says the big positives in a Japanese diet are soya products such as tofu, miso and soya sauce; seaweed (rich in antioxidants and minerals); and green tea, whose potent antioxidants prevent many forms of cancer. Many seasonings and sauces such as pickled ginger, sesame seeds, wasabi (Japanese mustard), stock made from seaweed, and dried bonito are healthy as well.
Large helpings of rice and other grains, a number of vegetables, fruits and legumes (particularly soya bean), moderate alcohol intake and very little red meat but at least three servings of fish a week are other healthy components of the traditional diet. On the negative side, Daisuke Hutami of the Japan Dietetic Association in Tokyo says that, traditionally, the Japanese diet lacked in protein and calcium. Various studies have concluded that this explains the diminutive stature of the Japanese as a race.
Today, milk and dairy products have been added to the Japanese food guide pyramid.
Considering the enormous regional variations in diet across India, it is difficult to ascertain a pattern. However, nutritionists pooling data from all over the country find that the average Indian diet is now rich in polished starch, low in fresh fruit and vegetables, and high in saturated fat. It is also characterized by a low intake of fresh fruits and vegetables and high cooking temperatures, which lead to decreased levels of Vitamin C. In recent years, consumption of grains has shifted from coarse (barley, rye, maize, sorghum and millet) to refined rice and wheat. Nutritionists and doctors ascribe the higher rates of diabetes and heart disease to these factors.
Their recommendation: Shift to oils that are rich in unsaturated fat, include omega-3 in the diet and go back to whole grains, plenty of fruits and vegetables. And, of course, the main foundation of all good food guide pyramids: Include plenty of exercise. In the past, a traditional Indian thali was rich in nutrients from all food groups: It had two types of vegetables—leafy green and others; paneer, curds, chutney, pickles, papad, one or two lentils and a dessert with rotis, typically made of millet and/or barley and whole wheat flour. Substitute roti with rice in a southern thali, minus the paneer and add buttermilk and it still had the same healthy mix.
THE HARVARD MODEL
In 1992, the US department of agriculture created the food guide pyramid in which the main message was that “fat is evil”. Today, the American pyramid has been revised substantially. But it’s still questioned by researchers from Harvard School of Public Health, who have built an alternative food pyramid which they call the Healthy Eating Pyramid. According to this diet plan, some types of fat—mainly those from plants and fish—keep arteries clear and hearts beating normally and possibly inhibit some forms of cancer.
In this, plant oils, including olive, canola, soya, corn, sunflower, peanut and other vegetable oils are at the bottom of the pyramid in the maximum use category, along with whole grain foods. White rice, white bread, potatoes and pasta and sweets have been banished to the top of the pyramid with red meat and butter to be used sparingly. It recommends a daily intake of vegetables and fruits, and good helpings of nuts, legumes, fish, poultry, eggs and dairy or calcium supplements.
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