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 B1, B2, retinol, γ-tocopherol, α-tocopherol, and β-carotene. Results β-carotene concentrations were not influenced by light exposure. Vitamin B1 was significantly ( p < 0.05) affected by light-exposure ( M = 0.23, SD = 0.01mg/L) compared to light-protected ( M = 0.27, SD = 0.01mg/L) samples. Vitamin B2 concentrations were reduced ( p < 0.05) by light-exposure in raw ( M = 62.1, SD = 0.61µg/L) and pasteurized ( M = 73.7, SD = 0.72µg/L) samples compared to light-protected raw samples ( M = 99.7, SD = 0.66µg/L). No other tested nutrients were affected by light exposure. Conclusions If milk is exposed to excessive amounts of light, Vitamins B1 and B2 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.