Physicians have long encouraged patients to eat more whole grains, fruits, vegetables, nuts and legumes to improve their health and control their weight. An investigation of 120,000 people over three decades whose results were published recently in JAMA Internal Medicine affirms this commonsense advice.
Analyzing 75,230 women from the Nurses’ Health Study (1984–2020) and 44,085 men from the Health Professionals Follow-Up Study (1986–2020), investigators found a significant association between four healthy eating patterns and a 20% risk reduction of early death.
People “who more carefully followed any of the healthy eating patterns—which all share a focus on consuming more whole grains, fruits, vegetables, nuts and legumes—were also less likely to die from cancer, cardiovascular illness and respiratory and neurodegenerative disease,” the study’s authors concluded.
For people who want to improve their diet and health, the results are reassuring, said lead study author Frank B. Hu, MD, PhD. He is professor and chair of the Harvard T.H. Chan School of Public Health Department of Nutrition. The study’s findings also demonstrate that people have a variety of healthy eating patterns to choose from, he said.
Tracking dietary habits over 30 years
Dr. Hu and colleagues wanted to assess whether there was a “best diet” for reducing mortality. The researchers analyzed four eating patterns recommended by standard dietary guidelines: the healthy eating index 2015 (HEI-2015), alternate Mediterranean diet (AMED) score, healthful plant-based diet index (HPDI), and alternate healthy eating index (AHEI).
AHEI “was constructed by my colleagues here at Harvard,” said Dr. Hu. “We reviewed extensive amounts of literature, came up with different components and created a score to reflect the best available evidence in terms of healthy eating and chronic disease reduction.”
Achieving these findings took several decades. Dr. Hu and colleagues followed the men for 34 years and the women for 36 years to assess long-term dietary habits. Each participant received a score for each of the four eating patterns at baseline. Some people might have scored very high on the plant-based diet index, for instance, but not that high in HEI, or vice versa, said Dr. Hu. The score was updated every four years during the follow-up of the cohorts.
Investigators compared the top 20th percentile of the score with the bottom 20th percentile of the score for everyone. “That helped us distinguish what discriminates between greater adherence to a certain dietary pattern versus very low adherence to that dietary pattern,” said Dr. Hu.
The main outcomes included total and cause-specific mortality, stratified by race and ethnicity.
All four linked to lower mortality
Across the board, all healthy eating patterns were associated with a 20% reduction in total mortality, as well as a lower risk of mortality due to cardiovascular disease or cancer. These associations were consistent in different racial and ethnic groups, including Hispanic, Black and white people, the study says.
Two of the scores—the AMED and AHEI—were associated with lower mortality from neurodegenerative disease. The reasons for this remain unclear. “More analysis and research are needed to identify dietary predictors for neurodegenerative disease,” Dr. Hu said.
There’s no “magic bullet”
Much confusion exists about popular diets and their link to chronic mortality, Dr. Hu noted. The reality, he said, is “there’s no magic bullet that can prolong life or that one diet is a better cure than another diet.”
Following core principles of healthy diets is what’s important, he added. All four dietary patterns in the study contained higher amounts of minimally processed kind of foods and relatively lower amounts of ultraprocessed foods.
“Beyond that, I think people can have a lot of flexibility in terms of choosing different protein groups, different types of fruits and vegetables, and whether they want to be more semivegetarian or vegetarian.”
Create healthy diet patterns
Create your own healthy diet patterns to stick to and enjoy, advised Dr. Hu, who is now doing research on the impact of these different dietary patterns on individual variability in metabolic response.
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