By Barbara Troesch
Obesity rates have nearly doubled since the early 80s  and much has been speculated about the possible reasons for this rapid increase. It is clear that maternal obesity and excessive weight gain during pregnancy make it more likely that the child will become obese . However, even though the obesity seems to be inherited, the genes we receive from our parents cannot explain it as they take more than a few decades to change so dramatically. Lifestyle factors play an important role and they appear to influence our genes in a manner that can be transferred from one generation to the next – specific modifications, so-called epigenetic mechanisms, can turn individual genes on or off. While they take place throughout life, those initiated early on- in the womb and during infancy- seem to have particularly long-lasting effects. These adaptations help explain how obesity is passed on from the mother and possibly even the father to the child .
The interplay between nurture and nature is very complex. However, it seems that a so-called methyl-group (a small molecule), which can turn off a gene by attaching itself to it, lies at its center. In obese people, these add-ons affect genes (e.g. for appetite control) and luckily, they can be influenced to some degree by diet and exercise . Studies in animals show that the negative impact of a high-fat diet during pregnancy on the child’s weight disappears if the diet is rich in specific nutrients such as folate that provide these add-ons . This is supported by the findings that children of obese mothers with low folate levels were 43 percent more likely to become obese than those of obese mothers with adequate folate status .
The vitamin’s effect on the child’s body weight provides a compelling reason to ensure adequate folate intake as soon as a couple starts trying to get pregnant. As many pregnancies are still not planned, it is important for all women who can become pregnant to ensure adequate folate intake. This has been recommended because of its protective effect against neural tube defects, which are birth defects that result in stillbirth or severe malformations. Still, a large number of mothers-to-be are not using folate supplements . Maybe these new findings on its effect on obesity might help to convince more future mothers to take folate supplements – particularly as obesity might just be the tip of the iceberg, as emerging evidence indicates long-lasting effects on blood pressure, heart disease and dementia.