ATHENS, Ga .– Fish oil supplements are a booming billion dollar business. Most of this success comes from the reputation that fish oil (and the omega-3 fatty acids in it) has tremendous health benefits – including improving heart health. Unfortunately, a new study has found that only people with a certain genetic makeup will see these benefits. Incidentally, University of Georgia researchers say fish oil pills can actually increase your risk of heart disease.
The study’s author, Kaixiong Ye, notes that fish oil and omega-3s are known for their effects on triglycerides. This is a type of fat in the blood and a key marker of cardiovascular disease. While the study finds that some consumers can lower triglyceride levels from ingesting omega-3s, the results are not universal.
“We have known for several decades that higher levels of omega-3 fatty acids in the blood are linked to a lower risk of heart disease,” said Ye in a university press release. “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. “
Which genes are the best fit?
Yes team looked at four different fats in the blood: high-density lipoprotein, low-density lipoprotein, total cholesterol, and triglycerides. Researchers say all of these lipids are biomarkers of cardiovascular health and disease risk. The data comes from 70,000 participants in the UK Biobank, a comprehensive study of genetic and health information that involved half a million people.
The study’s authors divided the samples into two groups, the fish preparations (about 11,000) and the participants who did not. The team then performed a genome-wide scan and compared eight million genetic variants in these groups.
After 64 million tests, the results revealed a key variation in the GJB2 gene. Researchers say people with the AG genotype can lower their triglycerides by taking fish oil supplements. However, individuals with the AA genotype slightly increase this blood fat level by taking omega-3 supplements.
The team couldn’t definitively determine what happened to people who took fish oil with the third genotype, GG.
That might sound great, but how should you know what genotype you have? Ye says thanks to the rise of genetic testing companies going straight to the consumer, consumers can actually find out now.
One obstacle Ye notes is that companies are not yet providing information on specific genetic variants. To get around this, a tech-savvy customer should be able to download their raw data from the testing company. Ye says the ID for the variant of the specific genotype is rs112803755 (A> G).
So isn’t the healthy reputation of fish oil believable?
Researchers say their results explain why so many studies cast doubts about fish oil’s ability to improve heart health. Meanwhile, other reports have found conflicting data about its ability to improve depression, ADHD, and cancer risk.
“One possible explanation is that these clinical trials did not take into account the genotypes of the participants,” explains Ye. “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 the researchers find this specific gene that determines the body’s response to fish oil, they plan to test the direct effects between these supplements and cardiovascular disease.
“Personalizing and optimizing fish oil supplement recommendations based on a person’s unique genetic makeup can improve our understanding of nutrition and lead to significant improvements in human health and wellbeing,” concludes the assistant professor of genetics.
The study appears in the journal PLOS Genetics.