The Associations Between Light Exposure During Pumping and Holder Pasteurization and the Macronutrient and Vitamin Concentrations in Human Milk.

Background: During pumping, storage, and pasteurization human milk is exposed to light, which could affect the concentrations of light-sensitive vitamins. Currently, milk banks do not regulate light exposure.

Research Aim: The aim of this paper was to determine the influence of light exposure during pumping, storage, and pasteurization on (1) macronutrients, (2) select water-soluble vitamins, and (3) select fat-soluble vitamins.

Methods: All 13 participants donated 4 milk samples each. Each sample underwent 1 of 4 treatments: raw and light protected, raw and light exposed, pasteurized and light protected, and pasteurized and light exposed. Samples were analyzed for macronutrients and Vitamins B, B, retinol, γ-tocopherol, α-tocopherol, and β-carotene.

Results: β-carotene concentrations were not influenced by light exposure. Vitamin B was significantly ( < 0.05) affected by light-exposure ( = 0.23, = 0.01mg/L) compared to light-protected ( = 0.27, = 0.01mg/L) samples. Vitamin B concentrations were reduced ( < 0.05) by light-exposure in raw ( = 62.1, = 0.61µg/L) and pasteurized ( = 73.7, = 0.72µg/L) samples compared to light-protected raw samples ( = 99.7, = 0.66µg/L). No other tested nutrients were affected by light exposure.

Conclusions: If milk is exposed to excessive amounts of light, Vitamins B and B concentrations may degrade below the current Adequate Intake recommendations for infants 0-6 months of age, increasing the risk of insufficient vitamin supply to the exclusively human milk-fed infant. Thus, pumped or processed human milk should be protected from light to preserve milk vitamin concentrations.