A flash-heating technique that has previously been shown to inactivate HIV in breastmilk also preserves most of its vitamin content, according to a study reported in the August 1st edition of the Journal of Acquired Immune Deficiency Syndromes.
Infant feeding poses a dilemma for HIV prevention in resource-poor settings in Africa and elsewhere. Breastfeeding by HIV-positive mothers is a major cause of HIV transmission to infants, but alternatives such as formula feeding can cause even greater infant sickness and mortality. Flash-heating of expressed breast milk – a simple technique which women could perform at home – may offer a solution.
The flash-heating technique consists of bathing a jar containing expressed breast milk in water which is quickly brought to boiling point, with the milk and jar then immediately removed to cool to 37ºC. In a previously reported preliminary study, flash-heating was shown to be capable of inactivating infectious, cell-free HIV particles in breastmilk from HIV-positive mothers.
In this study, the same researchers obtained fresh breastmilk samples from 50 HIV-positive mothers in Durban, South Africa, between 2004 and 2005, and analysed levels of vitamins A, B2 (riboflavin), B6 (pyridoxine), B12, C, and folate before and after flash-heating. In the standardised protocol, the mothers expressed their own milk manually, after washing hands with soap and water. 50 ml samples of milk were placed in commercial 16 oz. food jars, and boiled in 450 ml of water in a 1-quart pan.
The post-heating vitamin concentrations were expressed as percentages of the pre-heat concentrations (with all concentrations calculated as geometric means). Vitamin A content was not significantly affected, with a post-heat concentration equal to 0.94 of the pre-heat concentration (95% confidence interval [CI], 0.84 to 1.05; p = 0.29).
Vitamins B12, C, and folate increased significantly in treated milk, to levels 1.12 (95% CI, 1.06 to 1.18; p<.001), 1.21 (95% CI, 1.01 to 1.44; p = 0.056), and 1.44 (95% CI, 1.23 to 1.69; p < 0.001) times the pre-heat levels, respectively.
Vitamins B2 and B6 were decreased to 0.59 (95% CI, 0.44 to 0.81; p = 0.002) and 0.96 (95% CI, 0.92 to 0.99; p = 0.008), respectively, of the pre-treatment levels. (The researchers note that the value for riboflavin (vitamin B2) should be interpreted with caution, as estimates were used for the lowest values.)
The researchers concluded that "most vitamin concentrations are retained after heating," and that "flash-heat may be a practical and nutritious infant feeding method for mothers in developing countries."
Reference:
Israel-Ballard KA et al. Vitamin content of breast milk from HIV-1–infected mothers before and after flash-heat treatment. J Acquir Immune Defic Syndr 48: 444–449, 2008.