While eating red meat that is rich in protein is linked with increased risk of heart disease, protein from nuts and seeds could be beneficial for the human heart, suggests a study including more than 80,000 participants.
The study, appearing in the International Journal of Epidemiology, found that people who consumed large amounts of meat protein experienced a 60 per cent increase in cardiovascular disease (CVD), while people who consumed large amounts of protein from nuts and seeds experienced a 40-per cent reduction in CVD.
"While dietary fats are part of the story in affecting risk of cardiovascular disease, proteins may also have important and largely overlooked independent effects on risk," said Gary Fraser, from Loma Linda University in California.
Fraser added that nutritionists have traditionally looked toward what he termed "bad fats" in meats and "helpful fats" in nuts and seeds as causal agents.
As a result of being high in unsaturated fat, nuts and seeds are traditionally included in the "good fat" category. However, it is also possible that "good protein" that also adds to their positive health impact.
"This new evidence suggests that the full picture probably also involves the biological effects of proteins in these foods," he said.
For the study, the team compared animal proteins versus plant proteins in 81,337 men and women.
Associations between the "meat" and "nuts and seeds" protein factors and cardiovascular outcomes were strong and could not be ascribed to other associated nutrients considered to be important for cardiovascular health.
Healthy diets can be advocated based on protein sources, preferring low contributions of protein from meat and higher intakes of plant protein from nuts and seeds, the study noted.