More protein, less carbs may cut heart risk

Researchers at Johns Hopkins University found that substituting about 10 per cent of calories from carbohydrate to either protein-rich foods, mostly from plant sources, or to monounsaturated fats, contained in olive and canola oil, had a greater benefit on the heart than a carbohydrate rich diet, similar to that known in the US as DASH (Dietary Approaches to Stop Hypertension).

The study, called the Optimal Macronutrient Intake Trial to Prevent Heart Disease (OmniHeart), compared the effects of three different diets, each consumed over a six-week period, on blood pressure and fat in the bloodstream of 164 adults with pre-hypertension.

The first of these diets was rich in carbohydrates, but in the other two diets, approximately 10 per cent of the calories from carbohydrate were replaced with either monounsaturated fat or protein. In the protein-rich diet, about half came from plants.

Each diet was found to lower blood pressure, low-density lipoprotein cholesterol, and estimated coronary heart disease risk. But when people reduced their carbohydrate intake, the benefits were greater.

Overall, the protein-rich diet decreased cardiovascular disease risk by 21 per cent, and the monounsaturated fat diet decreased risk by almost 20 per cent.

The carbohydrate-rich diet only decreased risk by roughly 16 per cent.

The findings were presented at the American Heart Association's annual meeting in Dallas yesterday and published in today’s issue of JAMA.