Milk cytokines and subclinical breast inflammation in Tanzanian women: effects of dietary red palm oil or sunflower oil supplementation

Previously, we have found that subclinical breast inflammation, as indicate d by raised breastmilk concentrations of sodium and the inflammatory cytoki ne, interleukin-8 (IL-8), was highly prevalent in Bangladesh and associated with poor infant growth. In order to investigate further the prevalence of subclinical breast inflammation and to assess the impact of dietary interv ention, we studied rural Tanzanian women taking part in a study of dietary sunflower or red palm oil supplementation during late pregnancy and lactati on. We measured breastmilk concentrations of IL-8, the anti-inflammatory cy tokine, transforming growth factor-beta 2 (TGF-beta) and the ratio of sodiu m to potassium. We also estimated systemic inflammation by plasma concentra tions of the acute phase proteins, alpha(1)-acid glycoprotein and C-reactiv e protein. There were highly significant intercorrelations among milk Na/K ratio and concentrations of IL-8 and TGF-beta, the last only after treatmen t with bile salts which also improved TGF-beta recovery in the enzyme-linke d immunosorbent assay (ELISA). Plasma acute phase protein concentrations te nded to correlate with milk Na/K ratio and IL-8, suggesting that subclinica l breast inflammation was related to systemic inflammation. Dietary supplem entation with vitamin E-rich sunflower oil but not provitamin A-containing red palm oil decreased milk Na/K, IL-8 and TGF-beta at 3 months postpartum; however, the effect was significant only for Na/K ratio. The results sugge st that milk Na/K ratio, IL-8, and TGF-beta all measure the same phenomenon of subclinical breast inflammation but that Na/K ratio, having the lowest assay variability, is the most useful. Subclinical breast inflammation may result in part from systemic inflammation and may be improved by increased dietary intake of vitamin E-rich sunflower oil.