- Researchers investigated the impact of different food groups on cardiovascular health.
- They found that diets rich in fruits, vegetables, legumes, nuts, whole-fat dairy, and fish were linked to lower cardiovascular risk.
- Further studies are needed to understand how much each component contributes to overall risk reduction.
Unhealthy diets are a major risk factor for cardiovascular disease (CVD). In particular, higher amounts of processed meats, refined grains, and sugar-sweetened beverages are known to increase cardiovascular risk.
Concurrently, diets such as the Dietary Approaches to Stop Hypertension (DASH) diet, Mediterranean and Healthy Eating Index (HEI) are linked to lower CVD risk. These diets all include increased consumption of:
- Fruit
- Vegetables
- Legumes
- Nuts
- Fish
However, recent studies, have shown that some foods—such as whole-fat dairy—previously thought to increase CVD risk may have neutral or beneficial effects. However, many of these new findings have yet to be incorporated into dietary guidelines.
Moreover, as most dietary studies have been conducted in North America, Europe, and East Asia, whether previous findings apply to other parts of the world remains to be seen.
Recently, researchers examined diets and health records from 80 countries across five continents.
They found that diets high in fruit, vegetables, nuts, legumes, fish, and whole-fat dairy are linked to a lower risk of CVD and mortality in all world regions. The findings were particularly strong for lower-income countries.
The study was published in theEuropean Heart Journal.
First, the researchers analyzed data from 166,762 individuals ages 35–70 years in 21 low, middle, and high-income countries across five continents. They followed the participants for an average of 9.3 years.
The researchers created a healthy diet score based on six food categories linked with lower mortality rates:
- fruit
- vegetables
- legumes
- nuts
- fish
- dairy
They called the diet score the ‘PURE’ diet score after the study it was based upon.
Altogether, the researchers noted that the average diet score was 2.95 and that healthier diet scores were more common in countries with higher per-capita gross national income.
They also recorded a total of 8,201 major CVD events and 10,076 deaths during the follow-up period.
Ultimately, participants with diet scores of 5 or 6 were significantly less likely than those with a diet score of 0 or 1 to experience cardiovascular complications. Altogether, they had a:
- 30% lower incidence of mortality
- 19% lower risk of stroke
- 18% lower risk of CVD
- 14% lower risk of heart attack
The researchers found similar results after applying the PURE diet score to data from five other studies involving 96,955 participants in 70 countries.
They added that the PURE diet score had a slightly stronger association with death or CVD than other common diet scores, including HEI, Mediterranean, and DASH diet scores.
However, the PURE diet score was significantly more predictive of mortality and major CVD events than the Planetary diet score.
The Planetary diet was developed as a way to balance a sustainable food system with a healthy diet. It is the most restrictive of the diets studied as it emphasizes plant-based food sources and limits red meat, poultry, and fish to 98 grams, 203 grams, and 196 grams per week.
Based on the PURE diet score, the researchers recommend eating daily:
- 5 servings of fruit and vegetables
- 0.5 serving of legumes
- one serving of nuts
- 0.3 servings of fish
- 2 servings of dairy
- 0.5 servings of red meat
- 0.3 servings of poultry
They also recommended 3-4 weekly servings of legumes and 2-3 weekly servings of fish per week.
Medical News Today spoke with Dr. Debbie Fetter, assistant professor of teaching nutrition at the University of California, Davis, who was not involved in the study, about how diets high in fruits, vegetables, nuts, legumes, fish, and whole grains may benefit cardiovascular health.
“Plant-source foods, such as fruits, vegetables, and whole-grains, are nutrient-dense and have protective factors, known as phytochemicals. Phytochemicals help reduce oxidation and lower inflammation, which helps protect against chronic diseases, like CVD,” said Dr. Fetter.
MNT also spoke with Dr. Mary Greene, a board-certified cardiologist at Manhattan Cardiology in New York City, who was also not involved in the study. She noted that some of the benefits of the diet may also stem from limiting processed foods.
“We know that limiting processed foods—foods that have been marred by human production, foods that contain additives, chemicals and preservatives to keep them shelf stable—can cause a lot of inflammation in the body, particularly affecting the cardiovascular system. Avoiding these types of foods will go a long way to preserve cardiovascular health,” explained Dr. Greene.
“The food groups identified by this study, when consumed in their most natural state, can help to preserve cardiovascular health,” she added.
MNT asked Dana Hunnes Ph.D., a senior clinical dietitian at the UCLA Medical Center in Los Angeles, who was not involved in the study, about its limitations. She noted that the study only reported associations and did not explain causation.
“The best we can do with this type of study is to say these six foods are associated with lower risk for cardiovascular disease, but it doesn’t really look at how powerful each of those six foods is in potentially ‘causing’ cardiovascular disease,” Dr. Hunnes explained.
She noted that this is important as it could be that most benefits occurred from eating more fruits, vegetables, nuts, and legumes and that those who ate these fruits just happened to eat fish and dairy, from which benefits may be smaller.
Dr. Greene added that the findings are easy to misconstrue. She noted that while a pint of decadent ice cream is technically a full-fat dairy product, it is also a highly processed and fattening food, meaning it is best avoided.
“However, a splash of heavy cream in your coffee in the morning would be a better alternative than a low fat/sugar-free flavored creamer—which is a highly processed food that contains chemicals linked to diabetes, obesity, and heart disease. Making the distinction when talking about these individual food groups is very important,” she added.
Dr. Fetter noted that the study underlies how focusing on nutrient-dense foods like fruits, vegetables, legumes, nuts, fish, and dairy can reduce CVD risk.
She added that it was interesting to see how the PURE diet score was more predictive of cardiovascular health and mortality than the comparably restrictive Planetary Diet Score.
“This finding supports varying your dietary pattern and suggests that if you do consume animal-source foods, you can do so in moderation rather than completely restrict or avoid them,” she noted.
“You don’t necessarily need to go completely plant-based to lower your risk of heart disease, but rather moderate amounts of fish and dairy were found to be linked to a reduced risk of CVD in this analysis,” she concluded.