“To the best of our knowledge, this is the first intervention study disclosing gene expression changes in normo- and dyslipidemic subjects after fish oil supplementation,” wrote researchers from Leibniz University of Hannover in Nutrition ＆ Metabolism.
“We suggest that n-3 PUFAs [polyunsaturated fatty acids] may have an antioxidative potential.”
Unanswered questions
Commenting independently on the study, Gretchen Vannice, MS, RD, Nutrition Research Consultant, Omega-3 RD Nutrition Consulting, told NutraIngredients-USA that there is an outstanding question regarding the impact of long-chain omega-3s, EPA and DHA, on oxidation in the human body.
“This question is due, in part, to the fact that EPA and DHA are unsaturated fatty acids and as such, are themselves susceptible to oxidation. At the same time, benefits of EPA and DHA in cardiovascular health have been proven.”
“What we learn from this study by Schmidt, et al, is that a healthy dose of EPA and DHA (2.7 grams/day) for a reasonable duration (12 weeks) does impact the generation of enzymes associated with oxidation and perhaps reducing oxidation in humans,” said Vannice.
“We still don’t know if reducing the production of pro-oxidants (and free radical production) or negating the impact of pro-oxidants is best, but what we learn from this study furthers what we’ve seen in animal and in vitro studies, that long-chain omega-3s do have positive, and likely protective, effects on health at the cellular (or tissue) level.
“During the supplementation period, the subjects in both groups improved their omega-3 levels, moving them into the omega-3 blood level associated with the lowest risk of sudden cardiac death, another benefit,” she added.
Study details
Led by Jan Philipp Schuchardt, the researchers recruited ten men with normal blood lipid levels and ten men with abnormal lipid levels (dyslipidemic), and provided them with 2.7 grams per day of fish oil (Dr. Loges + Co. GmbH) for 12 weeks. The daily EPA and DHA dose was 1.56 and 1.14 grams, respectively.
Gene expression analysis revealed that both groups displayed an increase in expression of antioxidative enzymes and a decrease in the expression of pro-oxidative enzymes.
“It appears that n-3 PUFAs not only upregulates antioxidative enzymes, but rather induces a specific interplay of differential regulations to generate an optimal balance of the oxidative status,” wrote the researchers.
Benefits for all
Vannice noted that benefits were shown in both groups of subjects – those with normal lipid levels and those with high lipid levels – suggests oxidative benefits from EPA and DHA may occur in those with and without cardiovascular risk.
“Further, this study suggests greater benefit in those with elevated lipid levels, and this stands to reason, given what we understand about the relationship of elevated lipids and increased oxidative stress; if EPA and DHA are going to have benefit, as suggested here, the benefit would be greater in those with greater stress load,” she said.
Source: Nutrition ＆ Metabolism
2012, 9:45, doi: 10.1186/1743-7075-9-45
“Transcriptome-based identification of antioxidative gene expression after fish oil supplementation in normo- and dyslipidemic men”
Authors: S. Schmidt, F. Stahl, K-O. Mutz, T. Scheper, A. Hahn, J.P. Schuchardt
Fish oil supplements were associated with up-regulation of expression of antioxidative enzymes, and the down-regulation of pro-oxidative enzymes, with effects particularly notable in people with abnormal blood lipid profiles.
