Animal protein vs. vegetable protein for heart health

The Study
The metabolic syndrome is a cluster of symptoms that is strongly associated with risk of heart disease, stroke, type 2 diabetes, and all cause mortality. It is diagnosed when at least three of the following are present: 1) A Waist circumference higher than 40 inches in men and 35 inches in women. 2) Blood glucose higher than 100 mg/dl. 3) Triglycerides higher than 150 mg/dl. 4) HDL cholesterol below 40 mg/dl in men and 50 mg/dl in women. 5) Hypertension. 

The researchers of this investigation wanted to see if the type and amount of protein in the diet influences symptoms of the metabolic syndrome. Sixty-two overweight men and women with metabolic syndrome were randomized into one of 3 heart healthy DASH (Dietary Approach to Stop Hypertension) diets: 1) 18% protein with two-thirds of the protein coming from plant sources. 2) 18% protein with two-thirds of the protein coming from animal sources, including lean beef. 3) 27% protein with two-thirds of the protein coming from animal sources, including lean beef. The initial goal of this 6 month intervention was weight loss followed by weight maintenance.

The results were interesting. All groups lost similar amounts of weight (about 5% of initial weight). All metabolic syndrome criteria decreased similarly independent of protein type and amount. American Journal of Clinical Nutrition 2015; 102:757-70.

Take Home Message

Many authors of diet books claim that animal protein increases risk of heart disease, and that a vegetarian diet is the only way to heart health. This study provides strong evidence against this theory. According to this study, if you choose animal proteins that are low in saturated fat, like chicken, turkey, fish, and even lean beef now and again, your ability to reduce symptoms of the metabolic syndrome are similar to eating a diet high in plant proteins. It appears that weight loss was the big driver of metabolic syndrome symptom reduction in this study.

So do not be afraid of lean animal proteins. They certainly have a place in a heart healthy diet. The big take home message here is to get your weight down to a healthy level.