Last week’s New England Journal of medicine has published an interesting article called ‘Epigenetic Signature of Obesity’1. Though it is “genetics” and “research”, it is not very difficult to understand if we simplify some of the things. In fact, the concept inheritance not alien to us. Article is about how overeating related obesity is transmitted from one generation to the next. It also gives us some food for thought.Here is my attempt to discuss the article in simple language with a try to avoid medical jargon.
From ages we know that children inherit some of their features, traits and qualities. Like father, like son. Despite of this knowledge, we do not know how exactly this happens or to what extent! No parents and children are exactly alike. We understand some of the mysteries of this complex world of inheritance as we understand chromosomes, DNA, genes and proteins. In simple terms one can say that genes are responsible for transfer of some of the features or some diseases from one generation to other. However some features or variation in the traits can be independent of the genes. The study of such cellular or physiological trait variations which are not caused by changes in the DNA or genes is called ‘epigenetics’. Obviously environmental factors also play a significant role in the expression or variation in different traits. So after knowing what epigenetics is about, now we move to the story of this interesting experiment Anita Ost and colleagues described in December 2014. 2 They used flies (Drosophila) for their experiment. They fed some of the male flies a diet high in sugar. This high sugar diet increased their fat (triglycerides) level (yes! it is similar to what happens with us humans) and they used another groups of male flies which were fed on normal fly food or very low sugar food. They got remarkable results in the offspring. These offspring were also divided in groups and were fed on high-sugar and normal diet. The adverse effect of father’s diet was not evident in offspring fed on normal diet. But in the group of offspring fed on high sugar diet showed that role of father’s diet was very important indeed. The progeny of flies fed on either very low or very high sugar showed increased levels of fats (triglycerides).
We already know that mother’s nutritional status affects the child in the womb. This is called as developmental programming. A study by Dr Yajnik from India ‘Transmission of obesity-adiposity and related disorders from mother to the baby’ is one of the studies which emphasize such effect. 3 Children of the mothers who are undernourished or overfed have higher chances of getting obese. Now, one has to ask the question whether father’s diet or nutritional status affect children? The answer is yes. Obesity related changes were seen not only Drosophila flies, but mammals such as mice and humans also show chemical changes in the chromatins (which are complex structures made up of DNA , RNA and proteins) . These scientists were also able to show the imbalance caused by such changes affected one particular protein named Su(var). They have found one clear ‘signature’ for obesity! So apart from genes, there are ways by which a trait like obesity can express themselves from one generation to other and environmental factors like diet can affect it.
Scientists will use this information to further benefit and we might get new tests to diagnose our susceptibility to obesity. We might even find treatment for it in the future. For now, we should think that how can this information help us apart from academic interest? Diet and other lifestyle related factors affect us immensely. Wrong food, sedentary lifestyle and risky habits like smoking damage your health; make you prone for diseases like obesity, diabetes and heart disease. Now we know that parent’s diet can affect children as well. In one study by Ng SF, it has been seen that high fat diet in fathers is related to beta cell dysfunction in daughter rats4. (Beta cell dysfunction can cause diabetes). We may actually damage beyond our own body and affect our children with faulty diet. Probably we have to be careful with other lifestyle-related risk factors as well. However there is also a possibility of reversing this effect by adopting a healthy lifestyle. You can be healthy if you want! Embrace the healthy diet, teach your children to eat right food and stay away from obesity and related problems. (Now there could be a debate upon what is right and what is wrong to eat. You are free to choose a healthy and balanced diet for yourself!)
There has always been an emphasis on mother’s health and her ‘responsibility’ for the baby’s health. This article in a way shows us that father is equally responsible for the baby’s health. Not just socially but also physically. Not only his genes but his lifestyle can affect the baby. So shouldn’t it be the duty of a future father to try and stay healthy? Many factors like diet, smoking and sedentary lifestyle can be modified. It will make fathers healthy and they could pass on the inheritance of health. So fathers beware!
- Susan E Ozanne. Epigenetic signatures of obesity. NEJM2015;372;973-974.
- Ost A, Lempradl A, Casas E, et al. Parental diet defines offspring chromatin state and intergenerational obesity. Cell 2014; 159; 1352-1364
3.Yajnik CS. Transmission of obesity-adiposity and related disorders from mother to the baby. Ann. Nutr Metab.2014;64 suppl 1:8-17