Researchers at Swinburne University of Technology in Melbourne, Australia, used a randomized, placebo-controlled, double-blind, parallel-groups clinical trial to examine the effects of fish oil and multivitamin supplementation on the incorporation of n-3 and n-6 fatty acids into red blood cells. For the study, 160 healthy adult humans were randomized to receive 6 g of fish oil, 6 g of fish oil plus a multivitamin, 3 g of fish oil plus a multivitamin or a placebo daily for 16 weeks.
Daily supplementation with 6 g of fish oil led to higher eicosapentaenoic acid (EPA) and a lower AA/EPA ratio, while docosahexaenoic acid (DHA) composition was unchanged following treatment. The long chain n-3 PUFA index and total n-3 fatty acid only increased after 6 g of fish oil was administered in combination with a daily multivitamin. As expected, 6 g of fish oil combined with a multivitamin was more effective at increasing n-3 fatty acid erythrocyte composition than 3 g of fish oil combined with a multivitamin.
Notably, analysis by gender revealed that all treatments increased EPA incorporation in females while, in males, EPA was only significantly increased by the 6 g fish oil multivitamin combination. There was considerable individual variability in the red blood cell incorporation of EPA and DHA at endpoint. Gender contributed to a large proportion of this variability with females generally showing higher LC n-3 PUFA composition at the end.
“The present results corroborate prior research demonstrating a differential uptake of n-3 LCPUFA between men and women, with more effective uptake seen in women,” Harry B. Rice, PhD, vice president, regulatory & scientific affairs at the Global Organization for EPA and DHA Omega-3s, told NutraIngredients-USA. “The results clearly suggest that gender needs to be accounted for when conducting omega-3 research.”
Indeed, the researchers noted that because some men may incorporate lower amounts of LC n-3 PUFA into red blood cells (despite sticking to intake guidelines), future dietary recommendations around LC n-3 PUFA intake may need to be gender specific.
“I've had people ask me if this means that some benefits may be seen in women, but not men,” Dr. Rice added. “I can't say for certain, but the evidence doesn't really point in that direction. For men, compared to women, the issue may boil down to getting additional EPA and DHA from food and supplements. Not only does future research need to account for potential gender differences, but recommended intakes may need to account for the same.”
“Randomized Controlled Trial Examining the Effects of Fish Oil and Multivitamin Supplementation on the Incorporation of n-3 and n-6 Fatty Acids into Red Blood Cells”
Authors: Andrew Pipingas, Robyn Cockerell, Natalie Grima, Andrew Sinclair, Con Stough, Andrew Scholey, Stephen Myers, Kevin Croft, Avni Sali, and Matthew P. Pase