Fish oil supplements are a billion dollar industry based on purported but unproven health benefits. Now, new research by a team led by a University of Georgia scientist shows that fish oil ingestion only offers health benefits if you have the right genetic makeup.
The study, led by Kaixiong Ye and published in PLOS Genetics, focused on fish oil (and the omega-3 fatty acids in it) and its effects on triglycerides, a type of fat in the blood and a biomarker of cardiovascular disease.
“We have known for several decades that higher levels of omega-3 fatty acids in the blood are linked to lower risk of heart disease,” said Ye, assistant professor of genetics at Franklin College of Arts and Sciences. “What we’ve found is that fish oil supplementation isn’t good for everyone; it depends on your genotype. If you have a certain genetic background, fish oil supplementation will help lower your triglycerides; fish oil supplement will actually increase your triglycerides. “
Ye’s team, including first author and graduate student Michael Francis, examined four blood lipids (fats) – high-density lipoprotein, low-density lipoprotein, total cholesterol, and triglycerides – which are biomarkers of cardiovascular disease. The data for their sample of 70,000 people comes from the UK Biobank, a large-scale cohort study that gathers genetic and health information from half a million participants.
The team divided the sample into two groups, those who took fish oil supplements (approximately 11,000) and those who did not take fish oil supplements. Then they performed a genome-wide scan for each group and tested 8 million genetic variants for comparison. After over 64 million tests, their results showed a significant genetic variant of the GJB2 gene. People with the AG genotype who took fish oil decreased their triglycerides. Those with the AA genotype who ingested fish oil increased their triglycerides slightly. (A third possible genotype, GG, was present in not enough study participants to draw conclusions.)
Determining your genotype isn’t as far-fetched as it sounds thanks to direct-to-consumer genetic testing companies. Companies may not yet report this specific genetic variant, but a tech-savvy consumer should be able to download the raw data and look at the specific location to discover the genotype, Ye said. The ID for the variant is rs112803755 (A> G).
The results of the study may also shed light on previous studies, most of which found that fish oil was of no benefit in preventing cardiovascular disease.
“One possible explanation is that these clinical trials did not take into account the genotypes of the participants,” Ye said. “Some participants may benefit from it, others may not. So if you mix them up and do the analysis, you won’t see the effects.”
Now that Ye has identified a specific gene that can alter a person’s response to fish oil supplementation, his next step will be to directly test the effects of fish oil on cardiovascular disease.
“Personalizing and optimizing fish oil supplement recommendations based on a person’s unique genetic makeup can improve our understanding of nutrition,” he said, “and result in significant improvements in human health and well-being.”
Materials provided by University of Georgia. Originally written by Allyson Mann. Note: The content can be edited in terms of style and length.