Nutrition experts have often advocated the “the Mediterranean diet,” which is rooted in fruits and vegetables, whole grains, fish and poultry. Now, a new study confirms that the type of fats found in the Mediterranean diet promote a balanced cholesterol profile.
Monounsaturated fats, found in such foods as nuts, avocados and olive oil, are already known to raise HDL (“healthy”) cholesterol levels. Now, analysts at Toronto’s St. Michael’s Hospital, who are studying ways to combine cholesterol-lowering foods to maximize their impact, have added monounsaturated fats to a vegetarian diet previously shown to lower LDL (“bad”) cholesterol by 28%.
They found that the pairing lowered bad cholesterol even more-by 35% – while also raising good cholesterol by 12.5%. Achieving its greatest benefit when the monounsaturated fats replaced carbohydrates in the diet.
The Canadian Medical Association Journal published their results.
“Our concern was that trying to raise HDL cholesterol with monounsaturated fats might have reduced the effectiveness of our cholesterol-lowering dietary portfolio,” said Dr. David Jenkins, the lead author of the study. “The fact that this was not the case has opened the way to a dietary approach with a potentially much stronger ability to reduce cardiovascular risk.”
Insufficient levels of HDL cholesterol and high levels of LDL cholesterol are risk factors for cardiovascular disease. The consumption of monounsaturated fats, common in the Mediterranean diet, is a current approach to raising good cholesterol levels.
In Jenkins’ study, patients with mild to moderately high levels of cholesterol ate a diet low in saturated fats for one month. For the next month, they ate a vegetarian diet that included oats, barley, psyllium, eggplant, okra, soy, almonds and a margarine enriched with plant sterols. Previous research has shown this diet lowers LDL cholesterol by approximately 30%.
For half the group, researchers substituted 13% of the calories from carbohydrates with sunflower oil or avocado oil, both high in monounsaturated fat. Researchers found a significant increase in HDL cholesterol in that group over the two-month period, along with the substantial reduction in LDL cholesterol. HDL levels did not change in the other group.
“The addition of monounsaturated fats increased HDL cholesterol and therefore may further enhance the cardioprotective effect of the cholesterol-lowering dietary portfolio without diminishing its cholesterol-lowering effect,” concluded Dr. Jenkins.