MedicalResearch.com Interview with:
Kaixiong (Calvin) Ye, PhD
Dept. of Biological Statistics & Computational Biology
MedicalResearch.com: What is the background for this study?
Response: Omega-6 and omega-3 fatty acids are critical for human brain development, cognitive function, immune response, and cardiovascular health. Physiologically active forms of omega-6 and omega-3 fatty acids, such as AA, EPA, and DHA, are readily available in meat and seafood, but are absent in most plant-based foods (e.g. fruits and vegetables). Instead, plant-based foods contain two precursor fatty acids, LA and ALA, which could be metabolized in our body and converted into physiologically active forms. Fatty acid desaturase (FADS) genes encode key enzymes for this biosynthesis.
We hypothesized that genetic variations in FADS genes that enhance the biosynthesis efficiency were adaptive to plant-based diets in traditional farming populations and thus became more frequent over time. Our study compiled a huge data set of genetic information (DNA) from both present-day and ancient individuals. For the first time, we examined the action of natural selection on humans for the past 30,000 years in Europe.
MedicalResearch.com: What are the main findings?
Response: We found that FADS genes have two different versions that were respectively adaptive to the meat/seafood-based diets of hunter-gatherers and to the plant-based diets of farmers. The meat/seafood-adaptive version increased its frequency from ~30% 30,000 years ago to ~60% right before the Agricultural Revolution 8,000 years ago, and decreased its frequency dramatically to only 10% in present-day Europeans. In contrast, during the same period, the frequency of the plant-adaptive version decreased from 32% to 0% and then increased to 63%. Functionally, the plant-adaptive version increases gene expression and enhanced biosynthesis of physiologically active fatty acids, while the effects for the meat/seafood-adaptive version are opposite.
MedicalResearch.com: What should clinicians and patients take away from your report?
Response: The same diets have different effects on different individuals, depending on the genetic backgrounds. Taking into account your genome and personalizing your diet is the ultimate way to achieve optimal health. Specifically, about omega-3 and omega-6 fatty acids, if you have the meat/seafood-adaptive version of the FADS genes, your diet should include more meat/seafood or additional supplementation. If you have the plant-adaptive version, a traditional plant-based diet is good for you.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Future research needs to establish additional links among genetic variation, dietary patterns, and health outcomes. Quantifying the effect of genetic variations is necessary for precision nutrition. The observation that plant-adaptive version was maladaptive to the meat/seafood diets of hunter-gatherers suggests the possibility that having too much omega-6 and omega-3 fatty acids might be detrimental to health. This possibility needs to be further investigated.
MedicalResearch.com: Is there anything else you would like to add?
Response: Human evolution is an ongoing process. Diet has played and will continue to play significant roles in shaping our genome. The drastic dietary change in the last few decades from the traditional plant-based diets to the meat-based westernized diet might once again switch the selection on different versions of FADS genes. The mismatch between our genome and diet might have been exemplified in the recent epidemic of human complex diseases.
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Citation: Kaixiong Ye, Feng Gao, David Wang, Ofer Bar-Yosef, Alon Keinan. Dietary adaptation of FADS genes in Europe varied across time and geography. Nature Ecology & Evolution, 2017; 1: 0167 DOI: 10.1038/s41559-017-0167
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