New study suggests health benefits of swapping animal proteins for plant proteins

Substituting one to two servings of animal proteins with plant proteins every day could lead to a small reduction in the three main cholesterol markers for cardiovascular disease prevention, a new study suggests.

The health benefits could be even greater if people combined plant proteins with other cholesterol-lowering foods such as viscous, water soluble fibres from oats, barley and psyllium, and plant sterols, said lead author Dr. John Sievenpiper of St. Michael's Hospital.

Dr. Sievenpiper led a systematic review and meta-analysis of 112 randomized control trials in which people substituted plant proteins for some animal proteins in their diets for at least three weeks. The results were published online today in the Journal of the American Heart Association.

Dr. Sievenpiper said the review indicated that replacing one to two servings of animal proteins with plant proteins every day - primarily soy, nuts and pulses (dried peas and beans, lentils and chickpeas) - could reduce the main cholesterol markers by about 5 per cent.

"That may not sound like much, but because people in North America eat very little plant protein, there is a real opportunity here to make some small changes to our diets and realize the health benefits," said Dr. Sievenpiper, a clinician scientist with the hospital's Clinical Nutrition and Risk Modification Centre.

Dr. Sievenpiper said previous studies have shown the cholesterol-lowering benefits of individual foods or food groups, but that this paper looked at the benefits of substituting any plant proteins for animal proteins. Most of the randomized control trials they studied used soy (plant) proteins to replace dairy (animal) proteins.

"We are seeing a major interest in plant-based diets from Mediterranean to vegetarian diets in the supermarket and the clinic, and this comprehensive analysis of the highest level of evidence from randomized trials provides us with more confidence that these diets are heart healthy," said Dr. Sievenpiper.

The study looked at the impact of replacing animal protein with plant protein of three key markers for cholesterol: low-density lipoprotein cholesterol (LDL or "bad" cholesterol, which contributes to fatty buildups in arteries and raises the risk for heart attack, stroke and peripheral artery disease); non-high density lipoprotein cholesterol (non-HDL-C, or total cholesterol minus HDL or healthy/good cholesterol) and apolipoprotein B (the proteins in bad cholesterol that clog arteries).