- 2 to 3 daily servings of fruit
- 2 to 3 daily servings of vegetables
- 3 to 4 servings of legumes per week
- 7 servings of nuts per week
- 2 to 3 servings of fish per week
- 14 servings per week of dairy products that were mainly whole fat
A score of 1 (healthy) was assigned for intake above the median in a given food group, and a score of 0 (unhealthy) for intake at or below the median, for a total of 0 to 6.
Among nearly 250,000 study participants across six continents, the average diet score was 2.95. During a median follow-up of 9.3 years, there were 15,707 deaths and 40,764 cardiovascular events.
Compared with the least healthy diet (score of 1 or less), the healthiest diet (score of 5 or more) was linked with the following:
- 30 percent lower risk of death
- 18 percent lower likelihood of heart disease
- 14 percent lower risk of myocardial infarction
- 19 percent lower risk of stroke
Associations between the healthy diet score and outcomes were confirmed in five independent studies, including a total of almost 100,000 people with heart disease in 70 countries.
The analyses were adjusted for factors that could influence the relationships, including age, sex, waist-to-hip ratio, education level, income, urban or rural location, physical activity, smoking status, diabetes, use of statins or high blood pressure medications, and total calorie intake.
“Overall, the findings suggest that increasing consumption of most natural foods — including whole-fat dairy together with fruits, vegetables, nuts, legumes, and fish — in countries with lower gross national incomes, where intakes are low partly due to cultural or economic factors, would most likely produce important reductions in CVD and death,” says Mente.
“This conclusion contrasts with the usual recommendations from the Western guidelines, which have largely focused on avoiding over-nutrition [overeating] or excess of foods including whole-dairy, rather than addressing the low intake of these foods,” he says.
Better Access to All Food Is Associated With Better Health
These findings support what we already know: Eating many whole, unprocessed foods, including fruits, vegetables, fish, nuts, and legumes, is healthy for us, says Liz Weinandy, MPH, RDN, a registered dietitian at The Ohio State University in Columbus. “The recommendations for eating these healthy foods go across many ‘diets,’ including the Mediterranean, DASH, and Dietary Guidelines for Americans,” she says.
“I like that this study focused more on what to eat than what not to eat. It’s nice to be able to tell people what to eat more of — in this case fruits, vegetables, nuts, legumes, and fish,” says Weinandy.
But the sheer number and diversity of people in the PURE study makes it challenging to interpret some of these findings, because the countries included differ in so many ways, says Christopher Gardner, MD, a nutrition researcher and professor at Stanford Medicine in Palo Alto, California. “I’m concerned that some of the results are more nuanced than is being presented,” he says.
Dr. Gardner points out that about two-thirds of the individuals that were part of this specific PURE analysis are from China, Southeast Asia, South Asia, and Africa. “Lactose intolerance is a condition found in the majority of people on the planet, particularly Asians,” he says.
It’s clear from the data included in the study that those people are consuming very little dairy, and yet they make up the majority of the people in the analysis, says Gardner. “The question for this group is likely not so much low-fat versus whole fat dairy, but whether they consume any dairy at all, or none, because of lactose intolerance. It seems odd to combine data from these countries with the others,” he says.
Overall, because the majority of the participants are from countries where food is not as plentiful, Gardner suspects the takeaway is actually that having greater access to food — all food — is associated with better health. “This makes me very cautious about trying to assign health benefits to specific components, like dairy or red meat,” he says.
Current Guidelines Recommend Nonfat or Low-Fat Dairy
But some experts see these findings as more evidence that current recommendations around whole-fat dairy should change. Many organizations, including the American Heart Association (AHA), recommend choosing nonfat or low-fat dairy products.
“The new results in PURE, in combination with prior reports, call for a reevaluation of unrelenting guidelines to avoid whole-fat dairy products. Investigations such as the one by Mente and colleagues remind us of the continuing and devastating rise in diet-related chronic diseases globally, and of the power of protective foods to help address these burdens,” wrote Dariush Mozaffarian, MD, PhD, a distinguished professor at the Friedman School of Nutrition Science and Policy at Tufts University in Boston, in an accompanying editorial.
It's time for national nutrition guidelines and food-based healthcare interventions to catch up to the science, because millions of lives depend on it, he stated.
One of those prior studies was published in September 2021 in PLoS Medicine. Researchers measured blood levels of a fatty acid found mostly in dairy foods in about 4,000 60-year-olds in Sweden and followed them for an average of 16 years. They found that people with the highest levels of these fatty acid had the lowest risk of cardiovascular disease. Researchers confirmed the findings after combining the Swedish results with similar data from the United States, Denmark, and the United Kingdom.
Should We Be Eating Whole-Fat Dairy?
This study shows full-fat dairy may have some benefits, but it was in a context of eating many other healthy foods, says Weinandy. “People should not move to full-fat dairy as a rule,” she says.
But a person can enjoy half-and-half in their coffee, a scoop of high fat ice cream occasionally, and a slice of cheese on their sandwich, she says. “The fat from those dairy products can fit in an overall healthy diet, no problem. Most adults can consume up to about 20 grams of saturated fat daily — so the fat in some of these full-fat dairy products, within that recommended amount,” she says.
Moderate amounts of dairy fat can fit in the overall context of a healthy diet, but it’s important to remember that there’s a large amount of research showing the saturated fat in dairy products is associated with higher bad cholesterol levels, says Weinandy.
Can Red Meat Be a Part of a Healthy Diet?
Unlike many other heart-healthy diets, the PURE diet doesn’t make any specific recommendations about red meat.
“We found that a healthy diet can be achieved in a number of ways that can fit personal or cultural preferences, and does not necessarily require either including or excluding animal foods from the diet. When we included red meat in the diet score in separate analyses, the findings were similar — that is, neither stronger nor weaker,” says Mente.
The PURE diet score is flexible, he says. “For example, vegetarians can achieve a healthy diet score by consuming plenty of fruits, vegetables, legumes, nuts, whole grains, and dairy foods. Conversely, nonvegetarians can achieve the same score by consuming plenty of fruits, vegetables, and legumes together with any one of dairy or fish, or even moderate amounts of red meat or poultry,” says Mente.
Although the study does not provide answers on red meat intake, there is quite a bit of research that high-fat red meat and processed meats of any kind are not good for our health overall, says Weinandy.
The AHA recommends choosing plant-based sources of protein, regularly eating fish and seafood, and eating lean and unprocessed meat. Red meat has more saturated fat, which is linked to higher blood cholesterol and can increase the risk of heart disease.
Bottom Line: New Study Shouldn’t Overrule What Is Currently Recommended
Combining nutrition and health data across 80 countries that differ in many ways that go beyond what types of foods they choose to consume has its downside — the opportunity for mixed or confusing messages is high, says Gardner. “I actually think the findings in this paper can be more confusing than helpful,” he adds.
Observational studies like these are valuable, because researchers can’t do randomized controlled trials that involve getting thousands of volunteers to agree to change their diet for many decades, and adhere to those changes just for the sake of answering scientific questions, says Gardner.
But the findings of observational studies are associations; in this case, the findings don’t prove that eating whole-fat dairy or the other foods in the PURE diet prevented heart disease or death, says Gardner.
“As much as I appreciate what these observational studies have to offer, we still have to interpret them with great caution, and put them in the context of mechanistic studies (studies that show how certain interventions impact processes in the body), shorter-term randomized controlled studies that look at risk factors rather than disease outcomes, and other observational studies — in this case, hundreds of other observational studies done that are not as confounded by the vast number of differences in the 80 countries being pooled in the PURE study,” he says.
Weinandy encourages people to stick to what is currently known and recommend for a healthy diet. “Look at the Dietary Guidelines for Americans for guidance, since these are based on the best and most current research. Healthy eating doesn’t have to be complicated. At the end of the day, there is room for some full-fat dairy products if the foundation of what we eat is solidly healthy,” she says.
