Human brain development is an incredibly complex process involving a host of different signals from the mother and the developing fetus. Although the fetus is protected to some extent by the placenta, the developing fetal brain is vulnerable to many exogenous influences. In particular, development of the fetal brain is influenced by the nutritional status of the mother, and malnutrition can increase the likelihood of developmental defects. Maintaining a healthy diet during pregnancy is important and knowing which foods will encourage normal fetal brain development is especially valuable.
Fetal Brain Development
The first signs of brain development occur early in pregnancy, about 16 days after conception, with the formation of the neural plate. This structure then begins to roll upward and fold, forming the neural tube. By Day 27, the neural tube is fully closed, beginning its transformation into the spinal cord and brain. The developing brain then separates into distinct regions that give rise to the future forebrain, midbrain and hindbrain. Between weeks 24 and 44 of gestation, these regions undergo remarkable structural and functional change, progressing from a simple structure to one that morphologically resembles the adult brain.
Neural tube closure is one of the most important steps of brain development in early pregnancy, and mothers should be aware of the nutritional requirements to avoid developmental complications.
Nutrients for Brain Development in Early Pregnancy
All nutrients are important for brain development, but some are of greater significance than others. These include protein, iron, zinc, selenium, iodine, folate, vitamin A, choline and long-chain polyunsaturated fatty acids. Folate and choline are particularly important during early pregnancy to prevent neural tube defects. Both of these factors are involved in the biosynthesis of methionine from homocysteine, although the exact mechanism by which they prevent neural tube defects is still unknown. Iodine is also especially significant, as iodine deficiency is the biggest cause of preventable mental retardation.
Foods to Encourage Healthy Brain Development
Expectant mothers should seek out dietary sources of folate and choline. Folate is especially high in leafy vegetables, such as spinach and asparagus, as well as in fresh beans, peas and lentils. It is also abundant in beef liver. Folic acid, the synthetic form of folate, is used to fortify some foods, such as flour and cereals, in a deliberate attempt to reduce the number of neural tube defects. Choline is found in a variety of foods including eggs, fish and meat. It is also especially high in beef liver.
Women who suffer from iodine deficiency are encouraged to supplement their diet to increase levels of the nutrient. Fish contains high levels of iodine, but pregnant women are discouraged from using this as a source, as fish can also contain dangerously high levels of mercury. Therefore, iodine supplements are the safest option.
Groups at Risk from Low Nutrient Levels
Depleted levels of any nutrient are often caused by insufficient intake, either through poor diet or malnutrition. A balanced, healthy diet is always recommended, especially for women aiming to conceive and during pregnancy. Certain drugs can also interfere with the body's nutrient balance, and individuals suffering from kidney and liver disease are also at risk of nutrient deficiencies. Alcoholics are another group at risk of nutrient deficiencies and are particularly prone to folate and choline deficiencies.
Developmental Anomalies from Nutrient Deficiency
Nutrient deficiencies during early pregnancy, especially deficiencies in folate and choline, will often lead to neural tube defects, the most common being spina bifida and anencephaly. Spina bifida occurs when the neural tube does not close properly, leading to damage of the spinal cord and paralysis. Anencephaly is more serious and emerges when much of the brain does not develop. Babies with this condition are stillborn or die shortly after birth.
References
- USDA Database for the Choline Content of Common Foods 2004
- The American Journal of Clinical Nutrition: Nutrition and the developing brain: nutrient properties and measurement
- The American Journal of Clinical Nutrition: Is folic acid good for everyone?
- Nutrition Reviews: Choline: an essential nutrient for public health
- The American Journal of Clinical Nutrition: Importance of methyl donors during reproduction
