Data from a predominantly male, normolipidemic, middle-aged cohort of 9,253 people showed that fish oil supplementation was not associated with an increase in LDL cholesterol levels.
In addition, supplementing with fish oil has been linked to increases in DHA levels in red blood cells (erythrocytes).
“[I]An increase in the omega-3 index and erythrocyte DHA over time was associated with a slight decrease in LDL-C levels, ”wrote the researchers, led by Dr. William Harris of the Fatty Acid Research Institute (FARI).
“These results can reassure individuals who wish to increase their omega-3 fatty acid intake (from food sources or supplements) by adopting healthier lifestyles that clinically significant adverse effects on LDL-C are unlikely.”
The potential cardiovascular benefits of omega-3 fatty acids were first reported about 50 years ago when Dyerberg, Hans Olaf Bang, and Aase Brøndum Nielsen published seminal articles on the subject in the American Journal of Clinical Nutrition in The Lancet in 1975.
To date, polyunsaturated fatty acids (PUFAs) have been linked to a number of cardiovascular benefits, from improving blood lipid levels to reducing the tendency to thrombosis, and from improving blood pressure and heart rate to reducing the risk of coronary artery disease (CHD) and Cardiac death.
While the triglyceride (TG) lowering effects of omega-3 fatty acids are well known for doses between 3 and 4 grams per day, there is disagreement in the scientific literature regarding the effects of DHA-containing products on LDL cholesterol levels.
A meta-analysis of 110 randomized placebo control studies in humans in 2018 found that EPA and DHA supplements cause both an increase in LDL and HDL cholesterol (AbuMweis et al., J. Hum Nutr Diet. Vol. 31 , pp. 67-84).
“Some of these inconsistent results may be due to study populations with different baseline TG levels, as seen with other TG-lowering agents,” said Dr. Harris and his co-authors. However, a recent scientific opinion from the American Heart Association concluded that there is no clear evidence that DHA-containing prescription omega-3 fatty acids, used as monotherapy or in combination with statins, cause LDL-C in patients increase with HTG [high triglyceride levels]. ‘”
For the new paper, Dr. Harris and his coworkers conducted a prospective observational study of 9,253 people and analyzed red cell DHA levels and LDL-C levels.
Dr. Harris told NutraIngredients-USA that 29% of the cohort were using statins, which corresponds to the general US population over 40 years of age. In addition, the smoking rates and BMI were the same as for VITAL.
“Well, I would say they were pretty representative of the typical American. So the results should be general, ”he added.
The analysis found that “regardless of concomitant changes in cholesterol lowering drug use, an increase in DHA was associated with a small but statistically significant decrease in LDL-C levels,” they write.
In fact, a 1% increase in red blood cell DHA levels was associated with a 1.9 mg / dL decrease in LDL cholesterol.
Importantly, the association between increased DHA and decreased LDL-C has been observed in people who took omega-3 fatty acids and in those who took no supplements, who most likely increased their DHA levels from dietary changes.
“Most people who take fish oil supplements don’t take doses large enough to move the LDL needle (1-2 g DHA per day),” said Dr. Harris. “It is the routine health conscious consumer who can take 1-2 fish oil pills per day that we are investigating here.”
Source: Journal of Clinical Lipidology
Published online before going to press, doi 10.1016 / j.jacl.2020.11.011
“Erythrocyte DHA Elevations Are Not Associated with Elevations in LDL Cholesterol: Longitudinal Study by the Cooper Center”
Authors: WS Harris et al.