MUNICH – A formula for scoring diet quality that during its development phase significantly correlated with overall survival received validation when tested using three independent, large data sets that together included almost 80,000 people.
With these new findings the PURE Healthy Diet Score had now shown consistent, significant correlations with overall survival and the incidence of MI and stroke in a total of about 218,000 people from 50 countries who had been followed in any of four separate studies. This new validation is especially notable because the optimal diet identified by the scoring system diverged from current American diet recommendations in two important ways: Optimal food consumption included three daily servings of full-fat dairy and 1.5 servings daily of unprocessed red meat, reported at the annual congress of the European Society of Cardiology. He explained this finding as possibly related to the global scope of the study, which included many people from low- or middle-income countries where average diets are usually low in important nutrients.
The PURE Healthy Diet Score should now be “considered for broad, global dietary recommendations,” Dr. Mente said in a video interview. Testing a diet profile in a large, randomized trial would be ideal, but also difficult to run. Until then, the only alternative for defining an evidence-based optimal diet is observational data, as in the current study. The PURE Healthy Diet Score “is ready for routine use,” said Dr. Mente, a clinical epidemiologist at McMaster University in Hamilton, Canada.
Dr. Mente and his associates developed the Pure Healthy Diet Score with data taken from 138,527 people enrolled in the Prospective Urban Rural Epidemiology () study. They published a pair of reports in 2017 with their initial findings that also included some of their first steps toward developing the score (Lancet. 2017 Nov 4; ; ). The PURE analysis identified seven food groups for which daily intake levels significantly linked with survival: fruits, vegetables, nuts, legumes, dairy, red meat, and fish. Based on this, they devised a scoring formula that gives a person a rating of 1-5 for each of these seven food types, from the lowest quintile of consumption, which scores 1, to the highest quintile, which scores 5. The result is a score than can range from 7 to 35. They then divided the PURE participants into quintiles based on their intakes of all seven food types and found the highest survival rate among people in the quintile with the highest intake level for all of the food groups.
The best-outcome quintile consumed on average about eight servings of fruits and vegetables daily, 2.5 servings of legumes and nuts, three servings of full-fat daily, 1.5 servings of unprocessed red meat, and 0.3 servings of fish (or about two servings of fish weekly). Energy consumption in the best-outcome quintile received 54% of calories as carbohydrates, 28% as fat, and 18% as protein. In contrast, the worst-outcomes quintile received 69% of calories from carbohydrates, 19% from fat, and 12% from protein.
In a model that adjusted for all measured confounders the people in PURE with the best-outcome diet had a statistically significant, 25% reduced all-cause mortality, compared with people in the quintile with the worst diet.
To validate the formula the researchers used data collected from three other trials run by their group at McMaster University: