Macro- and Micronutrients in Milk from Healthy Cambodian Mothers: Status and Interrelations

Abstract

Background: Except for low thiamin content, little is known about vitamins or macronutrients in milk from Cambodian mothers, and associations among milk nutrients.

Objectives: We measured fat-soluble vitamins (FSVs) and water-soluble vitamins (WSVs), and macronutrients, and explored internutrient associations in milk from Cambodian mothers.

Methods: Milk from women (aged 18-45 y, 3-27 wk postpartum, n = 68) who participated in a thiamin-fortification trial were analyzed for vitamins B-2 (riboflavin, FAD), B-3 (nicotinamide), B-5, B-6 (pyridoxal, pyridoxine), B-7, B-12, A, E [α-tocopherol and γ-tocopherol (γ-TPH)], carotenoids, carbohydrate (CHO), fat, and protein. Milk vitamin B-1 [thiamin, thiamin monophosphate (TMP), thiamin pyrophosphate (TPP)] was previously assessed for fortification effects. Milk nutrient concentrations were compared with the Adequate Intake (AI) values for infants aged 0-6 mo. Pearson correlation was used to examine internutrient associations after excluding nutrients affected by fortification.

Results: Fortification increased thiamin and B-1 and decreased γ-TPH. Less than 40% of milk samples met the AIs for all vitamins, and 10 samples did not reach any AI values for the analyzed nutrients. CHO, fat, and energy values were met in 1.5-11.8%, and protein in 48.5%, of the samples. Whereas fat, protein, and energy were related (all r < 0.5; P < 0.001) and associated with FSVs and WSVs, CHO correlated only with some WSVs. TPP was not correlated with B-1 vitamers, but with other WSVs (r = 0.28-0.58; P < 0.019). All FSVs, except α-carotene, were correlated with each other (r = 0.42-0.98; P < 0.002). TPP, FAD, B-2, and B-3 were associated with almost all FSVs (r = 0.24-0.63; P < 0.044).

Conclusions: Cambodian women might not provide sufficient nutrients to their exclusively breastfeeding infants. Besides thiamin, all other vitamins measured were much lower than the AI. There were many strong correlations among macronutrients and vitamins; the extent to which these are explained by maternal diet, milk volume, maternal physiology, or genetics requires additional exploration.

Keywords: Adequate Intake (AI); human milk; internutrient relations; macronutrients; micronutrients.