The 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, fish oil supplementation has been linked to an increase in DHA levels in red blood cells (erythrocytes).
“[I]Increases in the omega-3 index and erythrocyte DHA over time have been linked to slightly decreased LDL-C levels, ”the researchers, led by Dr. William Harris of the Fatty Acid Research Institute (FARI).
“These results can reassure those looking to increase their omega-3 intake (from food sources or supplements) through healthier lifestyles that clinically significant side effects to LDL-C are unlikely.”
The potential cardiovascular benefits of omega-3 dates were first reported about 50 years ago when Dyerberg, Hans Olaf Bang, and Aase Brøndum Nielsen published seminal work on the subject in The Lancet in the American Journal of Clinical Nutrition in 1975.
To date, polyunsaturated fatty acids (PUFAs) have been linked to a range of cardiovascular benefits, from improving blood lipid levels to reducing the risk of 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 about the effects of DHA-containing products on LDL cholesterol levels.
In fact, a 2018 meta-analysis of 110 randomized, placebo-controlled human clinical trials found that EPA and DHA supplements increased both LDL and HDL cholesterol (AbuMweis et al. J Hum Nutr Diet. 67-84).
“Part of this inconsistency in results could be due to study populations having different baseline TG levels, as seen with other TG-lowering agents,” said Dr. Harris and his co-authors. “Nonetheless, a recent scientific opinion from the American Heart Association concluded that there is no clear evidence that DHA-containing prescription omega-3 fatty acid compounds, used as monotherapy or in combination with statins, constitute LDL-C increase in patients with HTG [high triglyceride levels]. ‘”
For the new publication, Dr. Harris and his coworkers carried out a prospective observational study on 9,253 people and analyzed the DHA and LDL-C levels of the erythrocytes.
Dr. Harris told NutraIngredients-USA that 29% of the cohort use statins, which equates to the general US population over 40. In addition, the smoking rates were the same as with VITAL, as was the BMI.
“So 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 a concomitant change in cholesterol-lowering drug intake, 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 linked to a 1.9 mg / dL decrease in LDL cholesterol, they said.
Importantly, the association between increased DHA and decreased LDL-C has been observed in people who took omega-3s and in non-supplement users, 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),” Dr. Harris. “We are examining the routine health-conscious consumer who can take 1-2 fish oil tablets per day.”
Source: Journal of Clinical Lipidology
Published online in advance, doi 10.1016 / j.jacl.2020.11.011
“Elevations in Red Cell DHA Are Not Associated with Elevations in LDL Cholesterol: Longitudinal Study by the Cooper Center”
Authors: WS Harris et al.