UGA-led research shows advantages only with a certain genome
Fish oil supplements are a billion dollar industry based on purported but unproven health benefits. New research by a team led by a University of Georgia scientist now shows that fish oil ingestion will only bring 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. “We have found that supplementing with fish oil is not good for everyone. it depends on your genotype. If you have a certain genetic background, a fish oil supplement will help lower your triglycerides. But if you don’t have the right genotype, taking a fish oil supplement will actually increase your triglycerides. “
Ye’s team, including first author and graduate student Michael Francis, studied four blood lipids (fats) – high-density lipoprotein, low-density lipoprotein, total cholesterol, and triglycerides – that 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 collected genetic and health information from half a million participants.
The team divided the sample into two groups: those who take fish oil supplements (approximately 11,000) and those who do not take fish oil supplements. They then 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 undetectable in enough volunteer subjects to draw conclusions.)
Determining your genotype isn’t as far-fetched as it sounds thanks to genetic testing companies that go straight to the consumer. 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).
Look at previous fish oil studies
The results of the study could 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 didn’t take into account the genotypes of the participants,” Ye said. “Some participants may benefit from it and some may not. So if you mix them up and do the analysis, you won’t see the effects.”
After Ye identifies a specific gene that can alter an individual’s response to the fish oil supplement, 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.”
The study is co-authored by Yitang Sun and Jingqi Zhou of the University of Georgia; Changwei Li and Xiang Li at Tulane University; and J. Thomas Brenna at Cornell University and the University of Texas at Austin.