In recent years, heart-healthy eating styles, such as the DASH diet and Mediterranean diet have gained popularity. These types of diets advise users to eat more fruits, vegetables, nuts, beans and fish.
However, a new study, published on July 6 in the European Heart Journal, suggests that an additional food group should be included if you want to lessen the risk of heart disease and premature death, and this is full fat dairy.
Eating full fat dairy is normally discouraged due to its high levels of saturated fat, which tends to drive up unhealthy cholesterol levels. Moreover, its calorie density can also add to obesity.
But based on the latest study findings, the current advice to restrict dairy, especially whole fat dairy, to very low amounts in populations globally is not necessary or even appropriate, explains lead author Andrew Mente, PhD, researcher and assistant professor in the Department of Health Research Methods, Evidence, and Impact at McMaster University in Ontario, Canada.
Indeed, Dr. Mente suggests that a slight uptick in the consumption of full fat dairy products in low-income and middle-income countries could likely have positive effects on health. This unexpected discovery holds the potential for significant consequences on global dietary practices.
“It indicates that the biggest gains in avoiding premature cardiovascular disease and deaths globally is expected to occur by increasing the intake of healthy foods to a moderate degree, especially in poorer world regions,” he says.
It’s Better to Focus on What You Should Eat Than What to Avoid
Dr. Mente also says that the current recommendations on the best diets to avoid cardiovascular disease are mostly based on studies from decades ago. Moreover, they were generated from high-income countries, and with limited information on what most people eat these days from around the world.
As per Dr. Mente, “Dietary patterns differ markedly by different regions of the world, and so it is not known whether conclusions on diets derived from studies in high-income and Western countries — where excess intake of some key foods may be the predominant problem — is applicable to low- and middle-income countries, where inadequate intake of some key foods is a major concern.”
In order to identify the most advantageous dietary patterns, scientists devised a diet scoring system using foods associated with increased longevity from their extensive and ongoing global Prospective Urban and Rural Epidemiological (PURE) study.
The PURE diet included:
- 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 (indicating a healthy choice) was assigned for consumption above the median in a specific food group, while a score of 0 (reflecting an unhealthy choice) was given for a consumption at or below the median, resulting in a possible score ranging from 0 to 6.
Among a research cohort spanning nearly 250,000 participants across six continents, the mean diet score amounted to 2,95. Over a median follow-up period of 9.3 years, there were 15,707 fatalities and 40,764 incidents of cardiovascular events.
In comparison to those with the least healthy diet (a score of 1 or lower), individuals adhering to the healthiest diet (a score of 5 or higher) exhibited the following associations:
- 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
The connections between the health-conscious diet score and outcomes were validated through five separate studies, encompassing nearly 100,000 individuals with heart disease across 70 countries.
The analyses were meticulously adjusted for potential factors that might influence these relationships, including age, gender, waist-to-hip ratio, educational attainment, income, urban or rural residency, physical activity, smoking habits, diabetes, usage of stains or high blood pressure medications, and overall calories 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 Dr. 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 adds.
Better Health Linked to Better Access to All Food
According to Liz Weinandy, MPH, RDN, a registered dietitian at The Ohio State University in Columbus, the study findings support what experts already know, which is eating many whole, unprocessed foods, including fruits, vegetables, fish, nuts, and legumes, is healthy for us.
“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.
However, Christopher Gardner, MD, a nutrition researcher and professor at Stanford Medicine in Palo Alto, California explains that the sheer number and diversity of people in the PURE study make it hard to interpret some of the study findings since the countries included differ in many ways.
“I’m concerned that some of the results are more nuanced than is being presented,” he says.
In addition, Dr. Gardner points out that about two-thirds of the individuals who were part of this specific PURE analysis are from China, Southeast Asia, South Asia, and Africa.
He shares, “Lactose intolerance is a condition found in the majority of people on the planet, particularly Asians.”
The data from the study clearly shows that those who make up the majority of the participants in the study consume very little dairy, shares 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.
In general, since the majority of the participants are from countries where food is not as plentiful, Dr. Gardner believes 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 Food Guidelines Recommend Non-Fat or Low-Fat Dairy
A number of experts are turning to these findings as evidence that current recommendations with regard to whole-fat dairy should change. A number of organizations, including the American Heart Association (AHA), recommend choosing nonfat or low-fat dairy products.
Dariush Mozaffarian, MD, PhD, a distinguished professor at the Friedman School of Nutrition Science and Policy at Tufts University in Boston, wrote in an accompanying editorial,
“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.”
He also stated that 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.’
A preceding study, featured in PLoS Medicine in September 2021, involved the assessment of blood levels of a fatty acid primarily present in dairy products in a cohort of approximately 4,000 sixty-year-olds in Sweden. Over an average tracking period of 16 years, it was observed that individuals with the highest levels of this particular fatty acid exhibited the lowest risk of developing cardiovascular disease. Subsequent validation of these results was achieved by merging the Swedish data with comparable information from the United States, Denmark, and the United Kingdom.
Should Diets Include Whole-Fat Dairy?
Dr. Weinandy says this study shows full-fat dairy may have some benefits, but it was in the context of eating many other healthy foods. “People should not move to full-fat dairy as a rule,” she says.
She also adds ‘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.”
Dr. Weinandy also notes that while moderate quantities of dairy fat can be incorporated into a balanced diet, it’s crucial to keep in mind that extensive research has linked the saturated fat present in dairy items to elevated levels of LDL cholesterol.
Can Red Meat Be Included in A Health Diet?
Contrary to a number of other heart-healthy diets, the PURE diet doesn’t give any specific recommendations when it comes to 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 Dr. Mente.
Moreover, he says that the PURE diet score is flexible. Dr. Mente goes on to explain, “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.”
While the study doesn’t offer specific insights into red meat consumption, Dr. Weinandy emphasizes that existing research indicates that high-fat red meat and processed meats, in general, are not conducive to our overall well-being.
The American Heart Association (AHA) advises opting for plant-based protein sources, incorporating fish and seafood into one’s diet regularly, and selecting lean, unprocessed meat. Notably, red meat contains higher levels of saturated fat, a known factor associated with elevated blood cholesterol and an increased risk of heart disease.
The Bottom Line
As per Dr. Gardner, combining nutrition and health data over 80 countries that differ in so many ways goes beyond what types of food they tend to consume has a downside, which is the opportunity for mixed or confused messages.
“I actually think the findings in this paper can be more confusing than helpful,” he adds.
Observational studies, such as these, hold significant value because conducting randomized controlled trials involving thousands of participants committed to dietary changes over extended periods solely for scientific inquiries is not practically feasible, says Dr. Gardner.
It’s important to note that the results of observational studies establish associations. In this particular instance, the outcomes do not confirm that the consumption of whole-fat dairy or the inclusion of other elements in the PURE diet directly averted heart disease or mortality, clarifies Dr. Gardner.
He says, “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.”
As per Dr. Weinandy, she encourages people to stick to what is currently known and recommended 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.
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