Yes, you read that right, the absence of a gene allows you to consume large quantities of fats without having to worry about your triglycerides levels.
Scientists have long known the effects of Apolipoproteins (APO) in human fat transport and utilization. When present, ApoC-III that limits the body’s ability to metabolize fats called triglycerides. When absent, the body metabolizes all available triglycerides, leading to very low levels in blood. One of the best ways to to get more definitive answers about a gene is to completely remove it from an organism and observe the effects of its elimination. If the gene is absolutely essential to life, the organism does not survive. Otherwise, the organism survives with the effects of the genes removal, which the scientists study. The poor thing I have been referring to as “organism” is the humble mice, the organism of choice. Mice and other animals have to date saved countless human lives by sacrificing their own. Thank you!
A study on knockout mice in 2011 indeed showed that knocking out a gene known as APOC3 leads to very low levels of triglycerides. What is more interesting is that in 2017, a group of researchers studying inbreeding populations in pakistan found a human equivalent of the APOC3 deficient mice.
In Pakistan, first cousin marriages are fairly common. That raises the chances of parents passing identical copies of genes to their children. The research group sequenced the DNA of 10,503 Pakistanis who are participating in a long-term heart disease and diabetes study and found several fully knocked-out genes. The team then looked for abnormalities in about 200 clinical blood biomarkers such as cholesterol, triglycerides, etc.
In this study, the group identified a whole family where both parents and all nine of their children lack the APCO3 gene. When the family members were given a fat-laden milkshake, as part of the study, their blood fat levels barely rose, suggesting they have little artery-clogging fat in their bodies and should be protected against heart attacks. The family also seemed perfectly healthy, so ApoC-III–blocking drugs now in clinical testing should be safe.
Though, this study was about human knockouts (people in whom this gene is completely absent, which are extremely rare), the rest of us carry variations in the APOC3 gene which affects our triglyceride levels and heart health in various ways.
Learning about the APOC3 and other gene polymorphisms you carry can help you modulate dietary fat intake and other appropriate interventions that are optimal for your genetics.