health guides

Know your cholesterol components

Most of us are familiar with cholesterol, which refers to fats in the blood, and lipoproteins such as LDL and HDL (which carry cholesterol in the bloodstream). It is well known that high levels of total cholesterol and low-density lipoprotein (LDL) cholesterol are associated with increased risk of developing heart disease, while high levels of high-density lipoprotein (HDL) are considered to be protective.

Lipoproteins break down into even smaller components, however. Apolipoprotein (apo) B is a component of LDL cholesterol, and apo A-1 makes up a portion of HDL cholesterol. High levels of apo B are associated with an increased heart disease risk, while higher apo A-1 levels seem to be protective. Recent evidence suggests that these lipoproteins and their ratios in the bloodstream may be more useful tools for predicting heart disease and stroke risk than merely looking at LDL and HDL cholesterol levels.

Diet right

The study compared the effect of three different diets on lipoprotein levels and other measures of heart disease risk in 551 people aged 55 to 80 who were at high risk for developing heart disease.

• A control group that followed the American Heart Association low-fat dietary guidelines
• A group that followed the Mediterranean diet plus additional virgin olive oil
• A group that followed the Mediterranean diet with the addition of mixed nuts

Both Mediterranean diets had positive effects on LDL and HDL cholesterol levels. Compared with the low-fat diet group, the Mediterranean diet plus olive oil group had significantly lower apo B levels, higher apo A-1 levels, and lower apoB/apoA-1 ratios, suggesting a decreased heart disease risk in this group. About 8% of men in this group went from being in the “high risk for heart attack” category to “low risk.” Similarly, about 17% of women in the Mediterranean diet plus olive oil group went from “high” to “low” heart attack risk categories.

“Data from this study provide further evidence to recommend a Mediterranean diet rich in virgin olive oil as a useful tool for controlling heart disease, particularly in individuals at high risk,” said lead study author, Rosa Sola of the Human Nutrition Department at the School of Medicine, University Rovira i Virgili, Spain.

Mediterranean diet basics

The Mediterranean diet includes

• plenty of fresh vegetables and fruits, olive oil, nuts and seeds, whole grains, beans and other pulses,
• moderate amounts of seafood,
• some alcohol,
• lesser amounts of dairy, eggs, and poultry, and
• very little red meat and sugar.

(Atherosclerosis 2011;218:174–80)