A healthy and balanced diet is important for everyone to maintain at all times but for pregnant and breastfeeding women what is being consumed also affects the baby, probably more significantly than initially thought. There are many guides out there as to what pregnant women should eat such as this from the NHS. In the past, nutritional supplements have also been recommended to help top-up the essential vitamins needed to maintain a healthy pregnancy. New studies are also always being published, which means that official guidelines are constantly being reviewed and updated, such as this one on raw eggs.
The parental effect
The food consumed during pregnancy doesn’t just affect the growth of the baby but can have long term genetic effects as well. The genetic components of our offspring does not actually change, only the way in which it is expressed – in simple terms genes can be switched on or off, and this is called epigenetics.
A basic example of epigenetics at play is the seemingly inherited traits of type 2 diabetes. Type 2 diabetes is normally preceded by the term “adult-onset” because it was thought to develop over an adult’s lifetime because of repeated excess blood sugar levels. However, type 2 diabetes is increasingly found in younger people, with the risk of developing it increasing by 15% if one parent has it, or more alarmingly, 75% if both parents have it meaning that there are other factors involved.
Higher numbers of obesity have also been found within relatives. As it turns out, a preference for too much unhealthy food can be determined by what a mother eats during breastfeeding. A study of pregnant rats showed that a diet high in junk food had led to a lower offspring birth weight. More interestingly, regardless of what the mother ate during pregnancy, if the mother consumed a high fat and sugar diet during breastfeeding, their young stared to display a preference for these types of foods too. Furthermore, the ill-effects of obesity during pregnancy do not just affect your children but can last for up to three generations.
Mechanism of epigenetics
So how can a child inherit a disease, such as type 2 diabetes, that is thought to be due to behaviours accumulated over a person’s lifetime? Even though the basic genes passed on from parents to offspring will be the unaffected regardless of the parents’ behaviour, slight modifications explained by the science of epigenetics, can still happen.
A recent study breeding mice offspring to have identical DNA but subjecting them to different environments within the womb was found to vary the ribosomal DNA (rDNA). Certain rDNA were found to have been methylated, a type of epigenetic modification, in mothers who were fed a low protein diet. This slowed their expression leading to lighter offspring. rDNA is used in the body to form ribosomes, which in turn produce proteins in cells. Changes to these might also explain the long term differences in a body’s ability to regulate blood sugar levels potential and developing type 2 diabetes.
At the moment the heritability of type 2 diabetes and other similar conditions haven’t been explained fully in genomic studies but this breakthrough of looking at rDNA could help researchers clarify the genetic links, not only with pregnant mothers but with the behaviour of the father as well.
Just eat healthy!
The main message to take away is that eating healthily is not only important for yourself but also for generations after you. Remember that genetic links not only exist between what the mother eats and her offspring but also between a father’s lifestyle and his too.