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Watch what you eat: 1 in 5 deaths due to poor diet, reveals study

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  • Watch what you eat: 1 in 5 deaths due to poor diet, reveals study

A global study finds that diets high in sodium and low in whole grains and fruits result in most deaths.

“Let food be thy medicine, and medicine thy food”, said Hippocrates of Kos, one of the first people to recognise that diseases have natural rather than supernatural causes, hinting at the need to eat food that keeps us healthy and strong. Over time, his advice seems to have been forgotten as we have continued to fill our plates with unhealthy, processed, salted or sweetened foods. Now, a new study published in The Lancet, by researchers from the GBD 2017 Diet Collaborators, has raised the alarm on the need to change our eating habits. The study has found that globally, one in five deaths in 2017 were associated with poor diet. Cardiovascular diseases, followed by cancers and type 2 diabetes were the leading killers.

The researchers investigated the food habits of adults over 25 years of age across 195 countries between 1990 and 2017 and looked into death rates from non-communicable diseases in these populations. They then analysed the intake of these nutrients among people, estimated the risk of them causing different diseases, and calculated the number of deaths and disability-adjusted life years (DALYs) attributable to diet for each illness. DALY represents the number of years lost due to ill-health, disability or early death.

“Our systematic evaluation of dietary consumption patterns across 195 countries provides a comprehensive picture of the health effects of poor dietary habits at the population level. We found that improvement of diet could potentially prevent one in every five deaths globally”, say the authors summarising their findings.

The study found that in 2017, 11 million deaths and 255 million DALYs were due to poor diet. In 1990, this number was only 8 million. Globally, the top three factors leading to the most fatalities and DALYs were the high intake of sodium, low consumption of whole grains and low intake of fruits. “Our findings show that suboptimal diet is responsible for more deaths than any other risks globally, including tobacco smoking”, remark the authors, talking about their alarming findings.

The world consumed less healthy foods and nutrients in 2017, the study found. Globally, there was a marked decrease in the consumption of nuts and seeds, milk, and whole grains compared to optimal levels. However, unhealthy foods like sugar-sweetened beverages, processed meat and sodium were consumed exceeding optimal levels. Men ate more of both healthy and unhealthy foods than women, and so did adults aged 50–69 years. Some bright spots were Central Asia, which consumed optimal levels of vegetables; high-income Asia Pacific countries like Japan, which had healthy levels of omega-3 fatty acids intake; and consumption of legumes were optimal in parts of Latin America, Asia and Africa.

People in South Asia, including India, ate suboptimal levels of most nutrients—fruits, vegetables, whole grains, nuts and seeds, milk, calcium, fibre, omega-3 fatty acids found in oily fish and polyunsaturated fatty acids found in soybean oil, corn oil, and safflower oil. In fact, low intake of whole grains was a leading dietary risk factor for deaths and DALYs in a few countries including India. On the brighter side, our consumption of legumes was well above the optimal levels, and that of processed meat and sugar-sweetened beverages were in the healthy range. However, the levels of trans fats, present in hydrogenated vegetable oil, and sodium, whose principal source is table salt, were alarmingly high.

Age-standardised intake of dietary factors among adults aged 25 years or older at the global and regional level in 2017 [Image source]

In 2017, more than half of diet-related deaths and two-thirds of diet-related DALYs were attributable to high intake of sodium (3 million deaths and 70 million DALYs), low intake of whole grains (3 million deaths and 82 million DALYs), and low intake of fruits (2 million deaths and 65 million DALYs). Low intake of whole grains caused the most DALYs among men and women and was the leading risk factor for mortality among women. For men, sodium was the highest risk followed by low intake of whole grains and fruits.

Deaths due to cardiovascular diseases dominated populations that ate a diet low in whole grains, fruits and vegetables, nuts and seeds and omega-3 fatty acids, and high in sodium. Type 2 diabetes, which is prevalent in India, was found to be a cause of death in people who consumed a diet low in whole grains, fruits and nuts and seeds. Low intake of whole grains was also the leading risk for deaths and DALYs among young adults aged 25–50 years, while sodium ranked first among older adults aged above 70 years.

Among the world’s 20 most populous countries, Egypt had the highest diet-related deaths, and Japan had the lowest in 2017. China had the highest rates of deaths due to diet-related cardiovascular diseases and cancers, and Mexico had the most diet-related type2 diabetes deaths. The highest proportions of diet-related cardiovascular disease deaths and DALYs in 2017 were observed in Pakistan.  

Age-standardised mortality rate per 100 000 population (A) and DALY rate per 100 000 population (B) attributable to diet in 2017 [Image Source]

Most debates on healthy diets in the past have focused on sodium, sugar and fats, but the culprits lie elsewhere. “Our assessment shows that the leading dietary risk factors for mortality are diets high in sodium, low in whole grains, low in fruit, low in nuts and seeds, low in vegetables, and low in omega-3 fatty acids; each accounting for more than 2% of global deaths”, reiterate the authors. The findings highlight the need for comprehensive food system interventions to promote the production, distribution, and consumption of these foods across nations.

And, that is not easy! The eating habits of people all over the world are as diverse as the people themselves. “Given the complexity of dietary behaviours and the wide range of influences on diet, improving diet requires active collaboration of a variety of actors throughout the food system, along with policies targeting multiple sectors of the food system,” conclude the authors.