Low HDL-C levels and high LDL-C levels are a risk factor for cardiovascular disease. The addition of dietary monounsaturated fat, common in the Mediterranean diet, is a current approach to raising HDL-C levels.
The study included 24 patients (17 men and 7 postmenopausal women) who completed a very low saturated fat diet before being randomly assigned to either a high-MUFA diet or a low- MUFA diet. Both groups of patients were assigned to a specific vegetarian diet which included oats, barley, psyllium, eggplant, okra, soy, almonds and a plant sterol enriched margarine. In the high-MUFA group, the researchers substituted 13% of calories from carbohydrates with a high-MUFA sunflower oil, with the option of a partial exchange with avocado oil.
They found significant reductions in blood cholesterol levels over the two month study period for participants.
"The replacement of 13% of total calories from carbohydrate by monounsaturated fats in the dietary portfolio resulted in a 12.5% greater increase in HDL-C over the four weeks, while not altering the substantial LDL-C reduction," writes Dr. David Jenkins, Clinical Nutrition and Risk Factor Modification Centre, St. Michael's Hospital, Toronto, with coauthors.
Other strategies to raise HDL-C include exercise and moderate consumption of alcohol as well as weight loss and smoking cessation.
"The addition of MUFA increased HDL-C and therefore may further enhance the cardioprotective effect of the cholesterol-lowering dietary portfolio without diminishing its cholesterol-lowering effect," state the authors.
However, they state that the long-term effect on diets that are self-directed by patients needs to be determined as do cardiovascular outcomes.