Editor’s Note: Sign up for CNN’s Eat, But Better: Mediterranean Style newsletter, an eight-part series that guides you in an expert-backed eating lifestyle that’s good for your health.
You can reduce your risk of an early death for any reason by nearly 20%, just by eating more foods from your choice of four healthy eating patterns, according to a new study.
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 results of the study, published Monday in the journal JAMA Internal Medicine, show “there is more than one way to eat well and derive the attendant health benefits,” said Dr. David Katz, a lifestyle medicine specialist who was not involved in the study.
People often get bored with one way of eating, study coauthor Dr. Frank Hu said, “so this is good news. It means that we have a lot of flexibility in terms of creating our own healthy dietary patterns that can be tailored to individual food preferences, health conditions and cultures.
“For example, if you are eating healthy Mediterranean, and after a few months you want to try something different, you can switch to a DASH (Dietary Approaches to Stop Hypertension) diet or you can switch to a semi-vegetarian diet,” said Hu, a professor of nutrition and epidemiology and chair of the department of nutrition at the Harvard T.H. Chan School of Public Health. “Or you can follow US dietary guidelines and create your own healthy eating plate.”
A long-term study
The study followed the eating habits of 75,000 women participating in the Nurses’ Health Study and more than 44,000 men in the Health Professionals Follow-up Study over 36 years. None of the men and women had cardiovascular disease at the start of the study, and few were smokers. All filled out eating questionnaires every four years.
“This is one of the largest and longest-running cohort studies to examine recommended dietary patterns and the long-term risk of premature deaths and deaths from major diseases,” Hu said.
Hu and his team scored participants on how closely they followed four healthy eating styles that are in sync with current US dietary guidelines.
One is the Mediterranean diet, which stresses eating fruits, vegetables, whole grains, nuts, legumes, fish and a high amount of olive oil, Hu said. “This dietary pattern emphasizes healthy fats, especially monounsaturated fat, in addition to plant-based foods and moderate alcohol,” he said.
The next is called the healthful plant-based diet, which also focuses on eating more plant products but gives negative points for all animal products and any alcohol.
“It even discourages relatively healthy options, like fish or some dairy products,” Hu said, adding that the eating plan frowns on unhealthy plant-based foods such as potato products.
“So you can imagine that vegetarians are probably on the higher end of this diet score,” he said, “and people who eat a lot of animal products or highly processed carbohydrate foods would be at the lower end of this score.”
The Healthy Eating Index tracks whether people follow basic US nutritional guidelines, which stress healthy, plant-based foods, frown on red and processed meat, and discourage eating added sugar, unhealthy fats and alcohol, Hu said.
The Alternate Healthy Eating Index was developed at Harvard, Hu said, and uses the “best available evidence” to include foods and nutrients most strongly associated with a lower risk of chronic disease.
“We explicitly included nuts, seeds, whole grains and lower consumption of red and processed meats and sugar-sweetened beverages,” he added. “A moderate consumption of alcohol is allowed.”
Findings by disease
After each person’s eating pattern was scored, the participants were divided into five groups, or quintiles, from highest to lowest adherence to one or more of the eating patterns.
“The highest quintile of diet quality as compared to the lowest was associated with a roughly 20% reduction in all-cause mortality,” said Katz, president and founder of the nonprofit True Health Initiative, a global coalition of experts dedicated to evidence-based lifestyle medicine.
The study also found reductions in risk of death from certain chronic diseases if people improved their diet over time, Hu said.
Participants who improved the health of their diet by 25% could reduce their risk of dying from cardiovascular disease by a range of 6% to 13% and dying from cancer by 7% to 18%, he said. There was up to a 7% reduction in risk of death by neurodegenerative disease, such as dementia.
“Respiratory disease mortality reduction was actually much greater, reducing risk by 35% to 46%,” Hu said.
The study relied on participants’ self-reports of food preferences and therefore only showed an association, not a direct cause and effect, between eating habits and health outcomes. Still, the fact that the study asked about diets every four years over such a long time frame added weight to the findings, Hu said.
What is the takeaway of this large, long-term study?
“It’s never too late to adopt healthy eating patterns, and the benefits of eating a healthy diet can be substantial in terms of reducing total premature deaths and different causes of premature death,” Hu said.
“People also have a lot of flexibility in terms of creating their own healthy dietary pattern. But the common principles — eating more-plant based foods and fewer servings of red meat, processed meats, added sugar and sodium — should be there, no matter what kind of diet that you want to create.”