Researchers at Université Laval have used transcriptomics and metabolomics to analyse the health effects of omega-3 polyunsaturated fatty acid (PUFA) dietary supplements. The results provide new insight into how these chemicals work their benefits — and why they don’t affect everyone the same way. 

Previous studies on omega-3 supplementation have relied mainly on blood levels of triglycerides to track changes in the risk of cardiovascular disease. Results have been mixed. “We know that omega-3s decrease triglycerides, but we know also that not everybody responds the same way,” says Iwona Rudkowska, a post-doctoral fellow under the supervision of Marie-Claude Vohl at Laval’s Institute of Nutraceuticals and Functional Foods. The goal of the latest study was to use state-of-the-art analytical techniques to track those differences.

In a paper published in the Journal of Nutritional Biochemistry, Rudkowska and her colleagues describe how 30 test subjects closely followed the Canada Food Guide for two weeks, followed by a further six weeks during which they supplemented with three grams per day of omega-3 PUFAs. By using RNA microarrays to probe changes in gene transcripts, the team found that on average, 610 genes in men
and 250 genes in women were either up- or down-regulated in response to PUFA supplementation. Further analysis showed that most of these genes were associated with inflammation and hardening of the arteries, consistent with the purported benefits of these chemicals. However, triglyceride levels did not drop for all patients, and in about 30 per cent they actually increased. A follow-up paper on these results is published in the journal Genes and Nutrition.

Although the doses of PUFAs were artificially high in her patients, Rudkowska feels that the research supports the benefits of supplementing with fish or other sources of omega-3s where possible. More importantly, the study shows that transcriptomic techniques like RNA microarrays can detect changes faster and more accurately than traditional biomarkers like triglycerides. “The new techniques allow us to see the mechanisms of action, not just the biochemical end points,” says Rudkowska.