Big six: The foundation of optimal cardiovascular health depends on “protective foods,” study finds

30 Aug 2023 --- Fruits, vegetables, legumes, nuts, fish and whole-fat dairy products eaten in the right quantities have been identified as “protective foods” that lower the risks of heart attacks and strokes in adults by researchers from McMaster University, Hamilton Health Sciences, Canada and the Population Research Health Institute (PHRI).

The researchers used the diet score from the ongoing Prospective Urban and Rural Epidemiological (PURE) study and replicated that in five independent studies to measure health outcomes in different regions of the world and in people with and without prior cardiovascular disease (CVD), in an extensive study published in the European Heart Journal.

“We were unique in that focus. The other diet scores combined foods considered harmful – such as processed and ultra-processed foods – with foods and nutrients believed to be protective of one’s health,” says first author Andrew Mente and PHRI scientist.

“There is a recent increased focus on higher consumption of protective foods for disease prevention. Outside of larger amounts of fruits, vegetables, nuts and legumes, the researchers showed that moderation is key in consuming natural foods.”

Global CVD analysis
The academics analyzed data from 245,000 people in 80 countries via multiple studies. Previous research mainly focused on Western countries and diets that combined harmful, ultra-processed foods with nutrient-dense foods. This research was global in scope and focused on foods that are generally considered to be healthy.

“Previous diet scores – including the EAT-Lancet Planetary Diet and the Mediterranean Diet tested the relationship of diet to CVD and death mainly in Western countries. The PURE Healthy Diet Score included a good representation of high, middle and low-income countries,” explains Salim Yusuf, senior author and principal investigator of PURE.

The PURE score recommends an average daily intake of two to three servings of fruits and vegetables, one serving of nuts at two servings of dairy. 

The score also includes three to four weekly servings of legumes and two to three weekly servings of fish. Possible substitutes include one daily serving of whole grains and one unprocessed red meat or poultry.

Health benefits can be achieved by eating moderate amounts of whole grains or unprocessed meats.

“Moderate amounts of fish and whole-fat dairy are associated with a lower risk of CVD and mortality. The same health outcomes can be achieved with moderate consumption of grains and meats – as long as they are unrefined whole grains and unprocessed meats,” says Mente.

This week, two extensive studies were presented at the annual meeting of the European Society of Cardiology (ESC) which demonstrated the high propensity of ultra-processed foods (UPF) to cause cardiovascular disease and stroke. The research is prompting calls once again for government and industry action. 

How the diet score worksThe protective foods can significantly increase the diet score regardless of whether animal or plant proteins are eaten in higher quantities.
A diet score of four out of a possible six is considered optimal, the level where significant gains in health have been observed. Beyond this point, there are merely modest additional health gains. The researchers indicate that the score can be achieved in various ways, which don’t necessarily depend on including or excluding animal foods.

For example, vegetarians can score four by eating many fruits, vegetables, legumes, nuts, whole grains and dairy. The PURE score ranges from zero to six, with the higher scores indicating a healthier diet. A “least healthy” diet, about one point or less, has lower amounts of each food group.

A higher PURE healthy diet score was associated with a 6% lower risk of major CVD and 8% lower mortality risk. 

The research analysis adjusted for confounders such as socioeconomic status using education and the wealth index at a country level. Countries were categorized according to income. 

In addition, the ESC, in collaboration with the University of Oxford, has presented staggering figures about the cost of cardiovascular diseases on European health care expenses, estimated at €282 billion (US$305 billion) from data collected and processed in 2021. The cost of general health care and long-term care alone amounts to €155 billion (US$168 billion).

Urgent dietary adjustments underway 
According to the current study’s researchers, major new dietary recommendations have been revised recently to drop the upper limits of total fat and cholesterol. This has placed a heightened focus on “protective foods” and diet patterns that include them. However, public purchasing choices, industry formulations and policy actions have not yet been updated with this newer evidence. For example, consumers and industry are heavily focused on low-fat foods and have avoided nuts because they are considered “energy-dense.” 

Policy actions such as front-of-package nutrition labels in the UK, Chile’s black box warning labels and recently proposed warning labels in Canada are still focused on reducing certain nutrients, such as fat, saturated fat, added sugar and salt. 

These recommendations are similar to the WHO’s recently proposed major focus on low-fat, low-saturated fat diets. There are almost no national or international strategies and policies to increase a number of “protective foods”, the researchers say. 

By Inga de Jong