Time-of-day effects of consumption of fish oil-enriched sausages on serum lipid parameters and fatty acid composition in normolipidemic adults: A randomized, double-blind, placebo-controlled, and parallel-group pilot study Tatsuya Konishi Nutrition Available online 24 March 2021,
Highlights
• Time-of-day effects of fish oil intake in normolipidemic adults were investigated.
• Fish oil intake in the morning suppressed serum triglyceride levels.
• Morning fish oil intake decreased serum total saturated fatty acids.
• Morning fish oil intake decreased serum n-6 polyunsaturated fatty acids.
• Timing of fish oil intake for health appears more optimal in the morning.
The body clock controls diurnal rhythms of nutrient digestion, absorption and metabolism. Fish oil (FO) contains abundant n-3 polyunsaturated fatty acids (PUFA) including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) that are thought to lower triglycerides (TG). This randomized, placebo-controlled, double-blind, parallel-group trial aimed to confirm the effects of the time of FO intake on TG in 20 healthy Japanese adults (age, 20–60 y). They were assigned to one group that consumed sausages enriched with FO (DHA 1,010 mg and EPA 240 mg) in the morning and a placebo (DHA 40 mg and EPA 15 mg) in the evening (BF-FO) and another that consumed the FO-enriched sausages in the evening and the placebo in the morning (DN-FO). Serum lipid parameters, fatty acid (FA) composition, and the mRNA expression of lipogenic genes in circulating blood cells were evaluated in fasting blood samples before, and after four and eight weeks of FO intake.
Serum concentrations of TG and total saturated fatty acid (SFA) were significantly decreased in the BF-FO group, whereas those of n-3 PUFA were significantly, and identically increased in both groups. Serum concentrations of n-6 PUFA were significantly decreased in the BF-FO, but not in the DN-FO group. Messenger RNA expression of the lipogenic genes ACLY, SCD, and FASN, were similarly reduced in both groups.
These findings suggested that the timing of FO intake affects both serum FA concentrations and TG metabolism in normolipidemic humans. The mechanisms of these effects of FO on lipid metabolism require further investigation.