Exclusive breastfeeding is recommended for the first 6 months of life as it has numerous benefits to both the mother and baby (About Breastfeeding). While breastmilk provides all the nutrients that babies need, it is just as important to ensure the mother is getting proper nutrients as well. Nutrient requirements during lactation are increased to cover both the volume and concentration of breast milk (Bo Lonnerdal, 2016). Interestingly, women lose around 400 mg Calcium/day (~1 g/day with twins) through breastfeeding, and this demand is met by a roughly 5-10% loss of skeletal mineral content during the suggested 6 months of exclusion lactation (Kovacs, 2005). However, lost mineral content is fully restored within a few months of weaning, and is a natural process that occurs without long-term adverse consequences for the mother (Kovacs, 2005).
Factors that do affect milk composition include: maternal age, energy restriction, obesity, maternal nutrition, oral contraceptives, and delivery method/stress (Bo Lonnerdal, 2016). More specifically, the fatty acids, water- and fat-soluble vitamins (except folic acid), iodine, and selenium in breast milk are a direct result of maternal nutrition status. Milk can also be a vehicle for toxins, such as drugs/metabolites, viruses, nicotine, caffeine, and alcohol.
With that being said, it is imperative mothers consume adequate nutrition during lactation to ensure optimal development of their baby. The recommended energy intake during the first 6 months of lactation is an additional 500 kcal under the assumption that 170 kcal/day will be mobilized from energy stores accumulated in pregnancy (Picciano, 2003). After 6 months, the recommended energy intake is reduced to 400 kcal/day because milk production decreases to approximately 600 mL/day (Picciano, 2003). For those who avoid dairy, have lactose intolerance, or limit foods fortified with Vitamin D, a 10 µg Vitamin D supplement is recommended. Similarly, a Vitamin B12 supplement (2.6 µg /day) is recommended for lactating mothers who are vegetarians (“Do mothers need more calories while breastfeeding?,” ; Picciano, 2003).
While the effects of the maternal diet during lactation on long-term health in infants have been reported, there are limited studies in the literature (Koletzko et al., 2019). In general, breastfeeding women do not need to limit or avoid specific foods. An overall balanced diet with a variety of fruits, vegetables, complex carbohydrates, fiber, high quality protein, and unsaturated fatty acids is suggested. Although fish is an excellent source of protein and essential fatty acids, breastfeeding women should follow the US Food and Drug Administration’s advice regarding fish intake: if eating fish caught by friends or family, check for fish advisories. If there is no advisory, eat only one serving (4 oz.) and no other fish that week (“Do mothers need more calories while breastfeeding?,”). Additionally, limit fish consumption to between 8-12 oz of a variety per week, specifically choosing fish that are lower in mercury. More information can be found here: https://www.fda.gov/media/102331/download. As for caffeine, there are usually no adverse effects to the infant when consumed in low to moderate amounts (about 300 mg or less/day, which equates to about 2-3 cups of coffee). Preterm and younger newborn infant’s breakdown caffeine more slowly, so mothers of these infants might consider consuming even less than the 300 mg.
References
About Breastfeeding. Centers for Disease Control Retrieved from https://www.cdc.gov/breastfeeding/about-breastfeeding/index.html.
Bo Lonnerdal, P. (2016). Nutrition during Lactation. Lecture Presentation. Nutrition and Internal Medicine. University of California, Davis.
Do mothers need more calories while breastfeeding? (February 10, 2020). Breastfeeding: Maternal Diet. Retrieved from https://www.cdc.gov/breastfeeding/breastfeeding-special-circumstances/diet-and-micronutrients/maternal-diet.html
Koletzko, B., Godfrey, K. M., Poston, L., Szajewska, H., van Goudoever, J. B., de Waard, M., . . . EarlyNutrition Project Systematic Review, G. (2019). Nutrition During Pregnancy, Lactation and Early Childhood and its Implications for Maternal and Long-Term Child Health: The Early Nutrition Project Recommendations. Ann Nutr Metab, 74(2), 93-106. doi:10.1159/000496471
Kovacs, C. S. (2005). Calcium and bone metabolism during pregnancy and lactation. J Mammary Gland Biol Neoplasia, 10(2), 105-118. doi:10.1007/s10911-005-5394-0
Picciano, M. F. (2003). Pregnancy and Lactation: Physiological Adjustments, Nutritional Requirements and the Role of Dietary Supplements. The Journal of Nutrition, 133(6), 1997S-2002S. doi:10.1093
