One of the most effective ways to postpone aging and actually increase life span is through reducing calories in a mild but chronic way. When adults have this kind of mild restriction of calories, the central nervous system actually benefits and maintains cognitive function.
However, this is not true for calorie restriction before birth. We do know from previous studies that if you restrict calories prenatally there are a host of negative effects on mental and physical health in childhood but not much is known about later life impact.
In this week’s PNAS, is a study looking at prenatal under-nutrition and cognitive function in later life. At the end of WW11, a severe 5-month famine struck the cities in the western part of the Netherlands, with calories dropping to as low as 400 calories per day. A group of children born during this period of malnutrition was first studied at age 19 and were not found to have been affected by exposure to prenatal under-nutrition. Now, the same cohort, who are age 56 to 59, have been studied for cognitive function in later adulthood.
This group, when studied at later ages between 50 to 58, were found to have increased risks of coronary artery disease and type 2 diabetes. This has been attributed to prenatal exposure to famine. This study now examines the same cohort for impact on cognitive function in these later years.
Those who were exposed to prenatal famine and malnutrition were found to have smaller heads during adulthood. They did worse on testing for selective attention tasks. The effect was largest if they were exposed to this malnutrition earlier on in the pregnancy.
Selective attention task is a cognitive ability that declines with increasing age. When this decline is seen at this younger age, it may be an early marker for acceleration in the aging process for cognitive function.
The central nervous system is forming during the beginning of pregnancy gestation and it might be that famine impacts on the neurodevelopment. Another explanation may relate to vascular and blood flow. Early exposure to famine results in what is called a more atherogenic lipid profile and an increased risk of coronary artery disease. These kind of atherosclerotic changes may take place in the brain blood supply as well, leading to vascular damage.
The reduction in head size noted means a reduction in brain size as well and this is also associated with poorer cognitive performance in the elderly. The head size reduction was not found in the group at age 50, so head size is declining in this group as they age.
These findings are particularly interesting, and in speaking with the author, the concern is that some women are known to diet during pregnancy. It is critical that women do eat a well-balanced diet. Women who calorie restrict may be putting their babies at risk.
In addition, women who have extreme vomiting would also be at risk for malnutrition to the fetus. Indeed, the authors pointed out that women who eat a high-fat and high-sugar diet might be missing essential nutrients and vitamins. At the present time, we do not have long-term studies assessing this kind of information, which is why the Dutch Famine Study is so important.
The term pregorexia has been coined for women who limit calories and exercise to extremes when pregnant. The following complications have been associated with eating disorders during pregnancy:
low birth weight and delay in fetal growth
While weight gain during pregnancy is individualized based on many factors, it is critical to make sure you are getting all the right nutrients and vitamins.