Evaluating 50-years of research on diet and heart disease, a new review of 200-diets claiming to be heart healthy reveals, only a few indicate strong evidence of lowering the risk of heart disease.

Researchers say the analysis reaffirms the benefits of a Mediterranean diet rich in vegetables, nuts, whole grains, lots of fruits, olive oil and fish, indicated the strongest evidence of lowering the risk of heart disease.

In comparison, a Western diet, heavy on processed meats, red meat, refined grains and high-fat dairy foods, high in trans-fatty acids and foods with a high glycemic index, raises the risk of heart disease.  For example, processed baked goods and snacks, fried foods are high in trans-fatty acids in many cookies and French fries, while simple or refined carbohydrates like white bread, pasta, and rice, have a high glycemic index that spikes blood sugar levels.

However, while omega-3 fatty acids found in fish, whole grains, alcohol, vitamins E and C, beta carotene, folate, fruit, and fibre, show moderate evidence of lowering the risk of heart disease, more research is needed to conclusively prove this relationship.

Andrew Mente, PhD, from the Population Health Research Institute and colleagues carried out the review on diet and heart disease, publishing it in the Archives of Internal Medicine.

They analyzed 146-studies looking into the dietary habits of a particular group of individuals in relation to their risk of heart disease, including 43-studies of people assigned to a diet, or a comparison group in order to measure the effect on the risk of heart disease.

Pooling the results of the studies and then rating the strength of evidence behind various heart-healthy diet claims, only three specific dietary factors showed strong evidence of being proven heart disease fighters, namely:
"        A diet rich in vegetables.
"        Eating walnuts and other nuts rich in monounsaturated fatty acids.
"        A Mediterranean-style diet rich in vegetables, legumes, fruits, nuts, whole grains, cheese or yogurt, and fish.

Researchers also found:
"        A Western-style diet high in processed meats, red meat, butter, refined grains, and high-fat dairy products.
"        High-glycemic index foods.
"        Trans-fatty acids.

Strong evidence of negative effects following dietary factors on heart disease risk, though researchers say the evidence behind all other dietary factors was 'too modest to be conclusive'.  The question mark remains about whether meat, eggs and milk, including many other foods are good or bad for the heart.