Beta-carotene is a plant pigment that is converted into vitamin A in the body. Maternal vitamin A requirements are increased during lactation, but there are no specific guidelines for increased beta-carotene intake or indications for high-dose supplementation in nursing mothers. Typical beta-carotene intake in a Western diet is 6 to 8 mg daily. Beta-carotene is a normal component of human colostrum and mature milk, where it contributes to antioxidant defenses in the neonate.[1] A systematic review found that in infants younger than 6 months, those fed primarily human milk have greater blood carotenoid concentrations than those fed formula.[2] Some evidence suggests that there is a correlation between beta-carotene and infant motor development in exclusively breastfed infants, but not in overall psychomotor performance.[3] Beta-carotene supplementation during pregnancy and for 6 months postpartum in nursing mothers with poor diets in a resource-poor setting reduced the number of days of illness in the mothers, but does not reduce infant morbidity or mortality according to another study.[4,5] The bioavailability of beta-carotene is dependent on the fat content of the meal and the form in which it is administered, with synthetic pharmaceutical forms having the best bioavailability. High-dose beta-carotene supplements lead to a slow increase in breastmilk beta-carotene concentrations, with an accumulation half-life of about 9 days. Levels drop towards baseline slowly over several weeks after discontinuation. In general, beta-carotene is well tolerated, although excessive maternal intake of beta-carotene can lead to a harmless, reversible discoloration of the breastfed infant's skin.[6] In HIV-infected women, high-dose beta-carotene plus vitamin A supplementation increases the rate of HIV viral shedding into breastmilk and increases HIV infection in breastfed infants, although the mortality rate over the first 2 years of life is not increased.[7,8] The viral shedding may be a result of an increase in subclinical mastitis caused by beta-carotene.[9] Beta-carotene concentration in breastmilk is not affected by refrigeration, freezing, or low-temperature microwaving. The concentration does decrease when milk passes through a tube feeding system, regardless of light exposure.[10]
Dietary supplements do not require extensive pre-marketing approval from the U.S. Food and Drug Administration. Manufacturers are responsible to ensure the safety, but do not need to prove the safety and effectiveness of dietary supplements before they are marketed. Dietary supplements may contain multiple ingredients, and differences are often found between labeled and actual ingredients or their amounts. A manufacturer may contract with an independent organization to verify the quality of a product or its ingredients, but that does not certify the safety or effectiveness of a product. Because of the above issues, clinical testing results on one product may not be applicable to other products. More detailed information