A diet low in nutrients may cause more deaths worldwide than smoking or other unhealthful habits, suggests new research.
The Global Burden of Disease Study looked at dietary consumption between 1990 and 2017 in 195 countries, focusing on 15 types of food or nutrients.
In a paper that features in The Lancet, the study investigators conclude that, due to its contribution to noncommunicable diseases, poor diet accounted for 1 in 5, or 11 million, adult deaths in 2017.
Ranking the countries from lowest to highest rates of diet-related deaths puts Israel first, with 89 deaths per 100,000 people, and Uzbekistan last, with 892 per 100,000.
The United States, with 171 deaths per 100,000, comes in at 43rd place and the United Kingdom at 23rd, with 127 deaths per 100,000. India is in 118th place, and China is in 140th.
"This study," says study author Dr. Christopher J. L. Murray, who is director of the Institute for Health Metrics and Evaluation at the University of Washington in Seattle, "affirms what many have thought for several years — that poor diet is responsible for more deaths than any other risk factor in the world."
Little healthful, too much unhealthful food
In their analysis of global diets, the researchers looked at 15 items: fruits, vegetables, nuts and seeds, legumes, whole grains, fiber, calcium, milk, omega-3 fatty acids from seafood, polyunsaturated fats, trans fats, red meat, processed meat, sugary drinks, and sodium.
They found that the global diet in 2017 contained less than the ideal amounts of nearly all healthful food items. The biggest deficiency was in nuts and seeds, milk, and whole grains.
Consumption of nuts and seeds, for instance, was on average only 3 grams (g) per day, or around 12 percent of the optimal intake.
Consumption of milk was only 16 percent of optimal intake and whole grains was only 23 percent.
Alongside these, daily intakes of unhealthful dietary items "exceeded the optimal level globally." Sugary drink consumption, for example, "was far higher than the optimal intake," followed by the consumption of processed meat and sodium. Red meat consumption was just above the optimal level.
Insufficient healthful food more damaging
An important finding of the study was that insufficient intake of healthful foods could be just as, if not more, damaging than eating too many unhealthful foods.
The authors note that the diets that related to the most deaths were "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."
They found that each of these dietary factors accounted "for more than 2 percent of global deaths."
In addition, just three of these — whole grains, fruits, and sodium — accounted for more than half of the diet-related deaths and two-thirds of the years lost to diet-related ill health and disability.
Dr. Murray says that these results contrast with the fact that, over the last 20 years, policy discussions have tended to focus more on restricting unhealthful foods.
He and his colleagues suggest that campaigns should concentrate on rebalancing diets. They also urge that any changes to food production and distribution aimed to achieve this must consider the environmental impact on the climate, land, water, and soil.
Need to 'shift the focus'
In a linked editorial, Prof. Nita G. Forouhi and Prof. Nigel Unwin, both of the Medical Research Council Epidemiology Unit at the University of Cambridge in the U.K., agree with the authors in that "in a global context," and despite its limitations, the study offers "evidence to shift the focus" from restricting unhealthful food items to increasing healthful ones.
They suggest that it confirms a need to emphasize foods rather than nutrients. However, they also highlight some of the challenges of shifting the global diet toward a more healthful one, such as the "prohibitive" costs of fruits and vegetables.
For example, in low-income countries, "Two servings of fruits and three servings of vegetables per day per individual accounted for 52 percent of household income," compared with just 2 percent in high-income nations.
"While sodium, sugar, and fat have been the focus of policy debates over the past two decades, our assessment suggests the leading dietary risk factors are high intake of sodium or low intake of healthy foods, such as whole grains, fruit, nuts and seeds, and vegetables."
Dr. Christopher J. L. Murray