19.7: Summary

Each stage in life has special dietary needs and concerns. An unborn child is entirely dependent on the mother for nutrients and for protection against harmful substances. The fetus and its mother do not share a common blood supply. Instead, blood vessels intertwine in the placenta, and nutrients and other substances pass between them.

A good diet should begin before pregnancy to build up reserves and prevent deficiencies. A nutrient-dense diet is required during pregnancy, because nutrient needs increase far more than calorie needs. All women capable of becoming pregnant are advised to take folate/folic acid in a multivitamin pill or fortified food because folate deficiency in early pregnancy (typically before the first doctor’s visit) increases the risk of a neural tube defect in the fetus. Pregnant women are typically prescribed prenatal vitamin/mineral tablets, but a good diet is still important.

Alcohol consumed during pregnancy can damage the fetus. Most serious is fetal alcohol syndrome, which includes mental and growth deficiencies, and malformations. Alcohol passes freely through the placenta, so women are advised to abstain from alcohol during pregnancy or while trying to conceive.

Women of normal weight should gain about 25-35 pounds during pregnancy. Weight gain affects birth weight, a good predictor of health in the newborn.

Breastfeeding is the best way to feed a baby. It not only provides the best nutrition, but the mother uses up calories in making the milk. (This can reduce some of the fat stores she has accumulated during pregnancy.) Breast milk also provides protection and immunities against some diseases.

Breast milk along with some supplemental vitamin D is adequate for the first 6 months of life, and women are encouraged to breast feed for 6 months and, if possible, a year or more. Alcohol can get into breast milk, and should be avoided.

Solid foods introduced at 6 months provide iron and other nutrients that aren’t provided in adequate amounts by milk alone beyond 6 months of age. Breast milk and/or infant formula provides the protein that a baby needs, so supplemental foods should be mostly cereals, fruits, and vegetables. After the first year of life, the growth rate slows dramatically, and along with that, calorie needs.

Early childhood is a good time to establish good eating and exercise habits, by providing nutritious foods, lots of variety in foods, and by encouraging exercise. Good eating habits should also be encouraged during adolescence, as boys and girls begin making more and more of their own food choices.

When growth stops as adults, calorie needs may be less. Women generally need fewer calories than men, so they need to eat more nutrient-dense foods to get enough nutrients without excess calories. Iron deficiency is particularly common in women of childbearing age because of iron losses in menstruation, and increased needs during pregnancy. As explained earlier, women of childbearing age should get additional folate in a vitamin pill or in folate-fortified foods.

As we age, calorie needs decrease, as does the sense of taste, smell, and thirst. Combined with the reduced interest in eating that often accompanies reduced social interaction, the risk of nutrient deficiencies increase. Older adults need to eat nutrient-dense foods, and are advised to get supplemental vitamin B₁₂ in fortified food or a vitamin pill. Exercise can help increase the appetite and the intake of more calories and nutrients.

All through our lives, we tend to follow food and exercise habits learned during our early years, so it is important to establish those healthy habits as early in life as possible.

For meeting nutritional needs, there are dietary guidelines for various life stages, from infants to older adults myplate.gov/life-stages