Oats have been touted as a heart-healthy food since 1963 when a study found that they can lower cholesterol and reduce the risk of cardiovascular disease.

Multiple succeeding studies focused on LDL (bad) cholesterol, but new studies are finding that oats have an impact on two other cardiovascular markers — non-HDL cholesterol (total cholesterol minus the "H" or "healthy cholesterol") and apolipoprotein B, or apoB, a lipoprotein that carries bad cholesterol through the blood.

A new Canadian meta-analysis of randomized controlled trials has concluded that eating oat fiber can reduce all three markers — LDL cholesterol, non-HDL cholesterol, and apoB.

The results are especially important for people with metabolic syndrome and Type 2 diabetes, since they typically do not have elevated LDL cholesterol levels.

Dr. Vladimir Vuksan and his colleagues at Toronto's St. Michael's hospital looked at 58 clinical trials involving almost 4,000 people from around the world that assessed the effect of diets enriched with oat beta-glucan compared with controlled diets on LDL cholesterol, and, for the first time, on non-HDL cholesterol and apoB as well.

"Diets enriched with about 3.5 grams a day of beta-glucan fiber from oats were found to modestly improve LDL cholesterol, but also non-HDC and apoB compared to control diets," Dr. Vuksan said.

The review found that overall, LDL cholesterol was reduced by 4.2 per cent, non-HDL cholesterol by 4.8 per cent, and apoB by 2.3 per cent.

Oat bran contains double the amount of beta-glucan as in oatmeal. For example, one cup of cooked oat bran (88 calories) contains the same quantity of beta-glucan as double the amount of cooked oat meal (166 calories).

Oat bran can also be eaten as a cereal, used in some baked goods, or sprinkled on other foods.

Previous studies have found that eating 3 grams of oat fiber daily — the amount in a bowl of oatmeal — can lower total cholesterol levels by as much as 23 percent. Even small reductions are important since each 1 percent reduction in serum cholesterol reduces the risk of heart disease by 2 percent.

Other good sources of beta-glucan include barley, some mushrooms (shiitake), seaweed, baker's yeast, and algae.

The new study was published online in the British Journal of Nutrition.