Original article

According to new research based on an analysis of nearly 200 studies involving millions of people, despite many foods and diet being labeled as heart healthy only some food items have shown strong evidence of actually lowering heart disease risk.

Researchers in the study evaluated more than 50 years of research done on diet and heart disease and found that the Mediterranean diet consisting of lots of vegetables, fruits, nuts and fish showed a “strong evidence” of lowering heart disease risk.

Starchy carbohydrates such as white bread and food containing trans-fats found in many cookies and French fries were on the “bad” list. Meat, eggs and milk and many other foods were on the “question mark” list as there wasn’t strong evidence about whether they’re good or bad for the heart.

The review was conducted by Andrew Mente, PhD, of the Population Health Research Institute and colleagues, and published in the Archives of Internal Medicine. In it 146 studies were analyzed and dietary habits of a particular group of individuals were looked at in relation to their risk of heart disease. 43 otherstudies examined the results of people assigned to a diet versus a comparison group to measure the effect on heart disease risk.

The researchers collected all the results of the studies and rated the strength of evidence behind the various heart-healthy diet claims using a criteria developed by Sir Austin Bradford Hill, the late British scientist who helped establish a link between smoking and lung cancer. Under this when a number of studies on any food item or diet show a strong link with improved heart health, the food or diet is put on the top of the list.

Study co-author Dr. Sonia Anand of McMaster University in Hamilton, Ontario, said she hoped the findings “decrease the confusion around what we should eat and what we shouldn’t eat.”

Only three specific dietary factors showed strong evidence as proven heart disease fighters in the final analysis and they were a vegetable rich diet, eating nuts rich in monounsaturated fatty acids like walnuts and other nuts, and following a Mediterranean-style diet high in vegetables, legumes, fruits, nuts, whole grains, cheese or yogurt, and fish. Of these, only a Mediterranean-style diet has been shown in randomized controlledstudies to reduce the risk of heart disease.

The researchers also found that eating a Western style diet that was high in trans-fatty acids, or foods with a high glycemic index raised the risk of heart disease while foods with a high glycemic index caused blood sugar levels to spike. Processed baked goods and snacks and fried foods are high in trans-fatty acids while white bread, pasta, and rice have a high glycemic index.

Dietary factors, including omega-3 fatty acids found in fish, whole grains, alcohol, vitamins E and C, beta carotene, folate, fruit, and fiber were shown to have moderate evidence to support a heart-healthy claim According to researchers the evidence behind all other dietary factors was “too modest to be conclusive” and moreresearch is needed to conclusively prove the relationship between these dietary factors and heart disease risk.

Linda Van Horn, professor of preventive medicine at Northwestern University’s Feinberg School of Medicine, said “It’s really about the totality of the usual eating pattern, rather than whether you ate a hot dog on opening day of baseball season.” The Heart and Stroke Foundation of Canada and the Canadian Institutes of Health supported theresearch.