Diet, nutrition and physical activity are increasingly being recognised as strong foundations for healthy living and prevention of diseases. As the world population increases, incidences of undernutrition and overnutrition seem to rise concomitantly despite advancement in nutrition knowledge and efforts to bring down levels of malnutrition.
While on one side the life span is increasing, on the other, the quality of life is being compromised due to the onset of non-communicable diseases in adults. Very often, the changing dietary pattern and its effects on health have been a subject of debate, and lately, more than the agricultural production of foods, availability of processed foods is responsible for changing diets. The consequences do not look very promising, especially for the population from developing countries, who are either unaware or are unable to make smart choices in selecting food.
Nutrition transition refers to the change occurring in nutrient intakes consequent to alterations in dietary intakes aptly termed as dietary transition. The quantum of dietary transition has taken an irregular path historically. When we refer to pre-historic societies, food patterns were similar for thousands of years, if we are to believe the facts gathered as evidence available in paintings, sculptures, stone carvings and crude implements. Man depended totally on hunted and foraged foodstuffs, hence the dietary composition was much different from what we eat today.
However, a major change was effected with the advent of agriculture, nearly 10,000 years ago, when human beings started settling down near sources of water, started growing food, specifically grains and storing food for future use. Diets took a turn towards more grains, less of natural fruits, nuts, seeds and hunted animal meat.
With domestication of cattle, dairy foods were introduced. This would have been the first gradual era of change. People would also experience periodic episodes of famine due to natural calamities and pestilence during the course of time. Coming to the second era, the quantum of change took a leap, which is around 50 years ago. The key factor of change has been the availability of processed foods. The food consumption pattern trends are changing worldwide, very often influenced by external indirect and direct factors with probable negative impacts on health. Some of these are:
(i) Changes in the pattern of agricultural production, partly due to demand and supply scenario and largely due to changes in way foods can be produced, availability of irrigation facilities, large scale mechanisation, decrease in cultivable land, use of pesticides and fertilisers, large scale animal farming, better facilities for tapping marine foods, etc.
(ii) Changes in food processing sector making more of shelf stable packaged products available to consumer and
(iii) Consumer acceptance of processed traditional as well as new products, also driven by the capacity to buy.
The nutrition transition has also been facilitated by external factors such as rapid transport facilities, easy communication and later, liberalisation in inter-country trade. The main driving forces of these epidemiological shifts are a globalised world, rapid and uneven urbanisation, demographic shifts and inter- and intra-country migrations – all of which result in alterations in dietary practices. Changes in agricultural practices have increased the world’s capacity to provide food for its burgeoning population, there is also an increase in diversity of food provided with less seasonal dependence.
Demographic and epidemiologic transitions are accompanied by nutrition transition as the structure of diet and body composition also change, under and over nutrition co-exist, and increasing numbers of people consume unhealthy diets. This nutrition transition is accompanied by equally rapid changes in physical activity and in body composition of humans, which has resulted in a change in health status. There is a shift from endemic deficiency and infectious diseases, mostly of early life to epidemic chronic diseases, generally of later life.
Developing countries are also going through a demographic transition from rural societies with low life expectancy at birth and families with many children to urban societies with higher life expectancy at birth and smaller families.
Changes in nutrient intake
There has been an improvement in energy available over the years at all income levels, though hunger still exists in certain section of populations globally. Calorie intakes have increased worldwide, and more so in families with increasing income levels.
- The distribution of calories among carbohydrates, protein and fat is different from what it used to be. The amount of carbohydrates taken as a source of calories is showing a decline. The decline is more in upper income group than in lower income group. Most of the calories come from protein and fat.
- There is a marked increase in fat intake. It is very high (three folds) in higher income groups and lesser in others. There has also been a change in the compositional quality of fats consumed.
- The protein content remains constant over the years and through the income levels.
Alcohol consumption is seen only in high income groups and it provides a considerable amount of energy.
- The diets are deficient in micronutrients, specifically, iron, iodine, zinc, vitamin A, riboflavin and folic acid, though many countries have introduced fortified products.
- There is a decrease in intake of dietary fibre.
A major driver of change brought about in dietary patterns has been the availability of processed foods in the Indian market. The processed food market has witnessed an enormous increase with the acceptance of tertiary processed foods by consumers.
Post-independence, only primary processed products could be seen in the market shelves, which were gradually added with secondary processed foods in eighties in terms of convenience. These helped the housewives to spend less time in the kitchen offering convenience and women could look for work opportunities outside home. This also meant that more women could be educated and employed thus increasing the disposable income of family which could be spent on processed foods. Hence, slowly, the tertiary processed foods came to be totally accepted by urban population. This was helped by advances and innovations in Indian food industries - in technology, mechanisation and quality control and large scale manufacture.
While the acceptance of packaged processed foods is one side of the story, it should be noted that there has been an enormous increase in ready-to-eat catered foods through different types of catering units. This is where the quality control is questionable, while a certain level of hygiene is maintained in good facilities, in smaller units such as the local street food vendors, the quality is compromised. Customer is exposed to unsafe food prepared under unhygienic conditions, with non-permitted additives and low quality raw ingredients with least control over clean handling of food. However, acceptance of foods from diverse cultures is being brought about through such systems by all section of populations by making international cuisine affordable.
Changes in food supplies
- Coarse grains like millets have been replaced with fine grains, mostly wheat and rice, the after-effect of green revolution. Per capita availability and consumption of pulses has come down considerably due to decreased or stagnant production.
- Unpolished (hand-pounded) brown rice has been replaced with highly polished white rice. The valuable nutrients contained in rice bran are lost. Though some of the bran is being used for production of rice bran oil.
- There has been an increase in production of oilseeds, thus increasing the amount of edible oils available. Crude oils are replaced with refined oils, and the type of oils consumed are altered.
- Traditional fats, crude oils, ghee/butter are replaced with hydrogenated trans fats.
- Usage of processed, highly refined, packaged foods has been consistently increasing.
- The source of animal meat has been changed from wild animals to farm bred animals, which differs in composition.
- The organised cultivated agriculture has reduced the consumption of wildly grown varieties of plant food.
- Naturally available diverse varieties of food have been replaced by few varieties which are grown in an organised sector.
- Consumers prefer high sugar, high fat energy rich food devoid of dietary fibre and other essential micro nutrients.
- An enormous increase in consumption of energy rich beverages has occurred leading to overweight and obesity.
There has been considerable shift from traditional dietary patterns to that of one using food from different cultures, increasing number of eating out episodes, consumption of more refined and energy rich food as well as unsafe food. Shifting away from traditional diets has added on to the unhealthy dietary trends as both kinds of processed food, either packaged or commercially catered ready-to- eat meals or snacks can be unhealthy.
Increasing disease burden
Increased energy consumption, unhealthy diets and decreased physical activity are main factors for hypertension, insulin resistance, abnormal blood lipids, overweight/obesity and chronic diseases such as CVDs, cancer, and diabetes.
Globally it is estimated that approximately 2.7 million deaths are attributable to low fruit and vegetable intake while 1.9 million deaths are attributable to physical inactivity. At the present stage of India’s health transition, chronic diseases contribute to an estimated 53% of deaths and 44% of disability-adjusted life-years lost.
Cardiovascular diseases at present accounting for approximately 30% of mortality in the world, will be the largest cause of disability and death among all deaths in India in another decade. The prevalence of hypertension has been reported to range between 20-40% in urban adults and 12-17% among rural adults. The number of people with hypertension is expected to increase from 118.2 million in 2000 to 213.5 million in 2025, with nearly equal number of men and women. This also gives rise to probability of higher incidences of stroke.
Diabetes mellitus is the most common metabolic disease in the world and leading cause of blindness and end stage renal disease. It is a global pandemic projected to affect one in 20 people by the year 2025, secondary to aging population and obesity.
The Indian population notably has the highest prevalence of diabetes worldwide, almost 4% in rural population and 21% in urban population, and Indians are shown to exhibit high-risk metabolic profiles at younger ages and lower body mass index than their Western counterparts. Though genetic susceptibility may be one of the causative factors, steps to prevent the epidemic are needed.
While non-communicable diseases are leading causes of death, underweight together with iron, zinc and Vitamin A deficiencies in Indian children are still among biggest challenges. Undernutrition impairs physical growth, increases morbidity and mortality, impairs cognitive development, reduces economic productivity, and, later, increases the risk of chronic diseases and impacts on offspring birth weight, thus generating vicious cycle of malnutrition.
Shifting towards healthy foods
For tackling the problem of malnutrition, a lifecycle approach is needed as the intervention should start much before conception to make the mother healthy for going through the process of pregnancy and ensuring the health of offspring. A continued support through infancy, childhood and adolescence is needed for prevention of growth failure, stunting, wasting and micronutrient malnutrition.
Dietary approaches to delay the onset of non-communicable diseases include prevention of overweight and obesity, restricting the intake of total fat, cholesterol, trans-fat and alcohol, increased intake of fibre, omega-3 fatty acids, fruits and vegetables and in particular, dietary antioxidants. Dietary composition also influences life span and is mediated through the intake of energy, saturated fat, salt, calcium, folate, vitamins. Foods such as meat, nuts, fish, fruits and vegetables and wholegrain are beneficial.
The processed food industry can help the customer toward healthy food choices by adopting healthy practices such as marketing more of health foods with low fat, high or optimum fibre composition. Customers should be given option of more healthy food and promotion of unhealthy food like synthetic soft drinks through media should be restricted. Levels of additives and other chemicals should be reduced as much as possible. The catering industry needs awareness regarding hygienic food handling. Lastly the customer needs to be educated regarding healthy food choices while selecting a packaged processed food, eating out, or eating at home.
Dr. Jamuna Prakash
Professor, Department of Food Science and Nutrition,
University of Mysore