JOENSUU, Finland—Eating fatty fish, such as salmon, herring and mackerel, at least three to four times a week has been shown to boost levels of high-density lipoprotein (HDL) cholesterol and lessen the risk for cardiovascular disease, according to a new study published in the journal PLoS One.
Researchers at the University of Eastern Finland studied the combined effects of whole grains, fish and bilberries on serum metabolic profile and lipid transfer protein activities in subjects with the metabolic syndrome.
For the study 131 subjects with impaired glucose metabolism and features of the metabolic syndrome were randomized into three groups with 12-week periods according to a parallel study design. They consumed either whole grains and low postprandial insulin response grain products, fatty fish three times a week, and bilberries three portions per day; wholegrain and low postprandial insulin response grain products; or refined wheat breads as cereal products.
Altogether 106 subjects completed the study. Serum metabolic profile was studied using an NMR-based platform providing information on lipoprotein subclasses and lipids, as well as low-molecular-weight metabolites.
Positive changes in lipid metabolism were observed in participants who increased their intake of fish at least three to four meals per week. Study participants ate fatty fish, such as salmon, rainbow trout, herring and vendace; no added butter or cream was used in the preparation of fish.
They found a greater increase of fish intake was associated with increased concentration of large HDL particles, larger average diameter of HDL particles, and increased concentrations of large HDL lipid components, even though total levels of HDL cholesterol remained stable.
The results suggest that consumption of diet rich in whole grains, bilberries and especially fatty fish causes changes in HDL particles shifting their subclass distribution toward larger particles. These changes may be related to known protective functions of HDL such as reverse cholesterol transport and could partly explain the known protective effects of fish consumption against atherosclerosis. The researchers noted that a dietary approach to the treatment of increased overall and LDL cholesterol levels is important.
A 2012 study published in British Medical Journal found consuming two to four servings of oily fish, such as salmon, herring and mackerel that are rich in omega-3 fatty acids, may reduce the risk of stroke by 6%. In 2009, researchers at Beth Israel Deaconess Medical Center (BIDMC) found eating salmon or other fatty fish rich in omega-3 fatty acids once a week reduced men’s risk of heart failure.