One in five deaths associated with poor diet, Lancet study says

Over 11 million deaths worldwide can be attributed to poor diet, according to a new study published by The Lancet. In 2017, one in five deaths were associated with suboptimal nutrition, with cardiovascular disease being the biggest contributor, followed by cancer and type 2 diabetes.

The Global Burden of Disease study tracked trends in consumption of 15 dietary factors among adults 25 years old and older from 1990 to 2017 in 195 countries. It is considered one of the most comprehensive studies ever performed on the effects of nutrition on human health and mortality.

By using a comparative risk assessment approach, researchers estimated the proportion of disease-specific burden attributed to each dietary risk factor, which included diets low in fruits, vegetables, legumes, whole grains, nuts and seeds, milk, fiber, calcium, seafood omega-3 fatty acids, polyunsaturated fats, as well as diets high in red meat, processed meat, sugar-sweetened beverages, trans fatty acids, and sodium.

Researchers looked at intake of each dietary factor, the effect size of the dietary factor on disease endpoint, and the level of intake associated with the lowest risk of mortality. Then, using disease-specific population attributable fractions, mortality, and disability-adjusted life-years (DALYS), researchers calculated the number of deaths and DALYS attributable to diet for each disease outcome.

The study found that 11 million deaths and 255 million DALYS were attributable to dietary risk factors. In particular, the leading dietary risk factors for death and DALYS globally were high sodium intake attributed to 70 million deaths, low intake of whole grains attributed to 3 million deaths, and low intake of fruits attributed to 2 million deaths.

The causes of these deaths included 10 million deaths from cardiovascular disease, 913,000 cancer deaths, and almost 339,000 deaths from type 2 diabetes. Deaths related to diet have increased from 8 million in 1990, largely due to increases in the population and population aging.

Some regions did manage to eat some dietary elements in the right amounts. For example, intake of vegetables was optimal in central Asia, as was seafood omega-3 fatty acids intake in high-income Asia Pacific, and legume intake in the Caribbean, tropical Latin America, south Asia, western sub-Saharan Africa, and eastern sub-Saharan Africa.

The largest shortfalls in optimal intake were seen for nuts and seeds, milk, whole grains, and the largest excesses were seen for sugar sweetened beverages, processed meat and sodium, according to the study abstract. On average, individuals worldwide consumed 12 percent of the recommended amount of nuts and seeds and drank around ten times the recommended amount of sugar sweetened beverage.

In addition, the global diet included 16 percent of the recommended amount of milk, about a quarter, 23 percent, of the recommended amount of whole grains, almost double, 90 percent more, the recommended range of processed meat, and 86 percent more sodium.

Authors note that there were varying levels of data available for each dietary factor, which increases the statistical uncertainty of these estimates.

The magnitude of diet-related disease highlights that many existing campaigns have not been effective, and the authors call for new food system interventions to rebalance diets around the world. The authors also note that changes must be sensitive to the environmental effects of the global food system to avoid adverse effects on climate change, biodiversity loss, land degradation, depleting freshwater, and soil degradation.

In January, The Lancet published the EAT-Lancet Commission, which provides the first scientific targets for a healthy diet from a sustainable food production system that operates within planetary boundaries for food. This report used 2016 data from the Global Burden of Disease study to estimate how far the world is from the healthy diet proposed.

Th new study provides a comprehensive picture of the potential impact of suboptimal diet on mortality and morbidity, highlighting the need for improving diet across nations. Researchers hope the findings will inform implementation of evidence-based dietary interventions and provide a platform for evaluation of their impact on human health annually.