Nutrition Science and Everyday Application - beta v 0.1

592 ALICE CALLAHAN, PHD, HEATHER LEONARD, MED, RDN, AND TAMBERLY POWELL, MS, RDN
ensure the baby’s energy needs are met. 9 Milk can also vary from day to night; nighttime milk
is higher in fat and the sleep-promoting hormone melatonin. 10 As breastfeeding continues
beyond 6 or 7 months, the levels of some vitamins and minerals begin to decline. This
is around the time that babies begin to eat some solid foods, so foods can help to fill in
nutritional gaps, while breast milk continues to be an important source of nutrients. 5
Breast milk provides enough of all of the micronutrients that young infants need with
two main exceptions: vitamin K and vitamin D. For this reason, newborns should receive a
vitamin K shot soon after birth; otherwise, vitamin K deficiency can lead to serious bleeding
disorders such as hemorrhage (see Unit 9). The American Academy of Pediatrics also
recommends that breastfed newborns be given a vitamin D supplement beginning in the
first few days of life and continuing until they are weaned to formula or cow’s milk, both of
which are fortified with adequate vitamin D. (Cow’s milk can be given beginning at 12 months
of age.) 11
Breast milk is also low in iron, although what little is there is absorbed very efficiently.
Newborns are born with a certain amount of iron absorbed from their mothers during
pregnancy, and they utilize this stored iron—in addition to that provided in breast milk—to
meet their iron requirement in early infancy. However, stored iron is depleted by around
4 months of age, so the American Academy of Pediatrics recommends that exclusively
breastfed infants begin taking an iron supplement at this age and continuing until they are
eating substantial amounts of iron-rich solid foods, such as meat or iron-fortified cereals.
Iron deficiency remains a significant problem, with 11% of 1-year-olds in the U.S. estimated
to be iron-deficient. 11 Iron is essential for brain development, and iron deficiency may cause
lasting developmental deficits. 12
NUTRITION FOR BREASTFEEDING MOTHERS
Breastfeeding mothers have nutrient requirements similar to women in the third trimester
of pregnancy. After all, they’re continuing to provide nutrients for their babies through
their milk, and milk production requires energy, macronutrients, micronutrients, and water.
Breastfeeding women have a remarkable ability to make enough milk to meet their babies’
nutrient needs even without an optimal diet, but eating well supports maternal health and
energy levels during this demanding time.
Breastfeeding increases energy requirements by about 450 to 500 calories per day, part
of which can be supplied by using adipose stored in pregnancy and part of which should be
supplied from greater caloric intake. In general, breastfeeding mothers can eat a wide variety
of foods, and they don’t usually need to avoid or restrict any specific foods. However, as in
pregnancy, they should continue to avoid high-mercury fish. Consuming low-mercury fish 2
to 3 times per week provides the omega-3 fatty acids DHA and EPA, which pass into breast
milk and support brain and eye development for the breastfeeding infant. 13 There is no
need to avoid common food allergens, such as peanut or dairy; avoiding these foods while
breastfeeding has not been shown to reduce babies’ chances of developing food allergies. 14
Sometimes women find that certain foods, such as garlic or spicy foods, are associated
with fussiness or gas in their infants, and they may experiment with avoiding those foods.
However, most infants don’t have a problem tolerating these foods. In fact, flavors from the
mother’s diet pass into breast milk, so researchers hypothesize that when mothers eat a