Genes can determine whether fish oil supplements are good or bad for you


One compelling study examining the link between genetics, diet, and heart health claims that the cardiovascular benefits often associated with taking fish oil supplements may only be seen in people of a certain genotype. The Association Study suggests that future nutritional recommendations can be optimized taking into account a person’s unique genetic makeup.

In recent years, a growing body of research has begun questioning the longstanding advice recommending omega-3 fish oil supplements as beneficial for those at high risk for cardiovascular disease. Several large-scale meta-analyzes found little benefit from taking the popular dietary supplement, and a phase 3 clinical trial testing a purified, concentrated form of a certain fatty acid found in fish oil was abandoned after preliminary data showed no benefit.

A new study published in the journal PLOS Genetics examined whether a novel gene-diet interaction could explain the apparent discordance in previous research. A genome-wide association study was carried out involving over 70,000 participants from the UK biobank.

A specific genetic variant that affects a gene called GJB2 was identified in the study as being significantly reduced in triglycerides in subjects taking fish oil supplements.

While this beneficial variant, called AG, resulted in triglyceride reductions in those taking the fish oil supplements, another variant, called AA, was associated with slightly higher triglyceride levels in those taking the supplements.

“We have found that supplementing with fish oil is not good for everyone. It depends on your genotype, ”says Kaixiong Ye, head of the new study. “If you have a certain genetic background, fish oil supplementation will help lower your triglycerides. But if you don’t have the right genotype, taking a fish oil supplement will actually increase your triglycerides. “

Of course, the researchers note the limitations inherent in this type of association study. While a plausible mechanism can be traced back to this gene and its effects on blood lipids, more focused work is needed to understand how supplementing with fish oil can interact with these genetic variants and affect cardiovascular health.

However, Ye says this novel association finding could explain why a large number of previous studies examining fish oil supplements and cardiovascular health have produced conflicting results.

“One possible explanation is that these clinical trials did not take into account the genotypes of the participants,” Ye notes. “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.”

If further research confirms this type of gene-diet interaction, it will give credibility to the emerging field of precision nutrition. The idea is that there may not be a “one size fits all” nutritional strategy and that in the future, nutritional advice could be tailored to individual subjects based on a variety of physiological factors, including genetics.

“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,” Ye concludes.

The new study was published in the journal PLOS Genetics.

Source: University of Georgia


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