It is well known that malnutrition or exposure to toxins during pregnancy can disrupt normal development and cause birth defects in infants. The most vulnerable period for serious damage is during the first two months of pregnancy. During this time, the cells are multiplying and their future functions are being determined. When this process is compromised, very serious and obvious birth defects can occur.
More recent research is identifying much more complex and less obvious effects of maternal nutrition on the child’s later health as an adult. Some of the first hints of later life consequences of maternal undernutrition during pregnancy come from the study of people born during the Dutch Hunger Winter of 1944-1945. These people were much more likely to become obese adults if their mothers had been exposed to famine conditions during the first half of their pregnancy.
QUESTION: How does undernutrition lead to obesity?
ANSWER: Animal studies show that reduced maternal nutrition generally results in lower infant birth weight. This typically results in rapid catch-up growth that often leads to obesity. How and why this leads to obesity may be related to brain development.
Researchers are finding that when the mother’s food intake is too low during pregnancy, fetal brain development can be impaired. This has been observed in animal studies even when the newborn’s birth weight is normal. Among the parts of the brain affected are the locations involved in appetite regulation and satiety. As a consequence, the animals overeat and become obese. This appears to explain what happened to people born during the Dutch Hunger Winter.
Q: Does this research on maternal undernutrition conflict with studies finding increased lifespan with restricted calorie intake?
A: The extent of calorie restriction found to increase lifespan in animal studies turns out to be enough to compromise fetal brain development and to have adverse lifelong consequences for the offspring. This was demonstrated by recent research on baboons conducted by research teams from Germany and Texas. When they reduced total food intake of pregnant baboons to 70 percent of the amount usually consumed, both fetal growth and maternal weight were still normal. However, structural development of parts of the fetal brain was compromised to an extent that can have negative effects on brain function throughout life. Pregnancy is clearly a stage of life when an intake of adequate calories and nutrients is required for normal brain development of the fetus.
Q: Can a mother’s undernutrition during pregnancy affect the future health of her offspring in other ways?
A: Based on studies of people born during the Dutch famine, limited nutrition during the early part of pregnancy led to increased risk of heart disease and stroke as well as mental problems such as schizophrenia and antisocial personality disorders. When famine mainly occurred during the middle of pregnancy, people were more likely to develop obstructive airway diseases. Those exposed to famine in the latter part of pregnancy were more likely to develop poor glucose tolerance as adults, increasing the risk of developing diabetes.
Clearly, good nutrition that provides adequate amounts of all essential nutrients and calories during all stages of pregnancy appears to be essential for the birth of a healthy baby that will grow into a healthy adult.
Joannie Dobbs, Ph.D., C.N.S., and Alan Titchenal, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii-Manoa. Dobbs also works with University Health Services.