Lactating women restricting milk are low on select nutrients.

OBJECTIVE

Currently there are no recommendations for vitamin/mineral supplementation for lactating women but supplementation may be important, particularly for those women who choose to restrict milk intake during lactation. The objective of this study was to assess nutrient adequacy for lactating women and compare their dietary intake, including supplements, between those who restrict milk and those who do not.

METHODS

A cohort of 175 healthy exclusively breast-feeding women (19-45 yrs) recruited from prenatal classes were divided into milk restrictors (RS) defined as milk intake < or = 250 ml/day and non-restrictors (NRS) (>250 ml/day) and followed for six months postpartum. Participants provided repeated 24-hr dietary recalls, detailed use of vitamin/mineral supplements and reasons for restricting milk.

STATISTICAL ANALYSES

Observed intakes were adjusted to remove day-to-day variability. Nutrient intakes were estimated for macronutrients and vitamins C, D, thiamin, riboflavin, niacin, and minerals, calcium and zinc, with and without vitamin/mineral supplements. Chi-square was used to compare the number of RS and NRS with intakes less than the Estimated Average Requirement (EAR).

RESULTS

Milk restriction was practiced by 23% of the sample. Sixty per cent of RS reported protein intakes <EAR compared to 38% of NRS (chi(2) = 6.22, p < 0.05). Prior to supplementation, mean levels of calcium and vitamin D intakes for RS were below the adequate intake level (AI) and lower than NRS estimated intakes (p < 0.05). Following supplementation, mean levels of these nutrients reached AI for both groups. RS remained lower than NRS. RS had lower energy intakes than NRS (p < 0.05) but no difference in weight loss at 6 months was noted. A higher proportion of RS were below the EAR for thiamin, riboflavin and zinc.

CONCLUSIONS

Milk restriction compromised protein and nutrient intakes in lactating women who restricted milk to <250 mL. Vitamin/mineral supplements helped exclusively breastfeeding milk restrictors improve their vitamin D and calcium intakes. Milk restriction is not recommended during lactation and where unavoidable, nutrients provided by milk should be compensated for by other foods or supplements.