Breastfeeding and reduced risk of childhood obesity: will randomized trials on breastfeeding promotion give the definite answer?

N-labeled internal standards (4). Using this method, Tsikas (4) reported endogenous plasma nitrite concentrations in the order of 12 lM compared with our value of 4 lM. Apart from dietary intake of nitrate/nitrite, there are likely to be other factors that could affect the accurate measurement of plasma nitrite, eg, its short half-life of 110 s in human blood (5). Standardization of dietary sources of nitrate and nitrite will be an important factor to consider in future work in this area.