Joseph G. A. J. Hautvast

Lack of improvement in vitamin A status with increased consumption of dark-green leafy vegetables

There is little evidence to support the general assumption that dietary carotenoids can improve vitamin A status. We investigated in Bogor District, West Java, Indonesia, the effect of an additional daily portion of dark-green leafy vegetables on vitamin A and iron status in women with low haemoglobin concentrations (< 130 g/L) who were breastfeeding a child of 3-17 months. Every day for 12 weeks one group (n = 57) received stir-fried vegetables, a second (n = 62) received a wafer enriched with beta-carotene, iron, vitamin C, and folic acid, and a third (n = 56) received a non-enriched wafer to control for additional energy intake. The vegetable supplement and the enriched wafer contained 3.5 mg beta-carotene, 5.2 mg and 4.8 mg iron, and 7.8 g and 4.4 g fat, respectively. Assignment to vegetable or wafer groups was by village. Wafers were distributed double-masked. In the enriched-wafer group there were increases in serum retinol (mean increase 0.32 [95% CI 0.23-0.40] mumol/L), breastmilk retinol (0.59 [0.35-0.84] mumol/L), and serum beta-carotene (0.73 [0.59-0.88] mumol/L). These changes differed significantly from those in the other two groups, in which the only significant changes were small increases in breastmilk retinol in the control-wafer group (0.16 [0.02-0.30] mumol/L) and in serum beta-carotene in the vegetable group (0.03 [0-0.06] mumol/L). Changes in iron status were similar in all three groups. An additional daily portion of dark-green leafy vegetables did not improve vitamin A status, whereas a similar amount of beta-carotene from a simpler matrix produced a strong improvement. These results suggest that the approach to combating vitamin A deficiency by increases in the consumption of provitamin A carotenoids from vegetables should be re-examined.

Variation in mineral concentrations in breast milk of guatemalan mothers and a tribute to professor Clive E. West

Dhonukshe-Rutten et al. (1) have explored an interesting and seldom investigated topic by assessing the day-to-day variation in human milk concentrations of iron, zinc and copper. Professor Clive E. West, the guarantor of the work, died on 27 August 2004. The topic of investigation is an integral part of his quest for improving nutrition and health through a better understanding of the relationship between diet and disease, particularly with regard to micronutrients. Together with a vast number of fellows he undertook a large number of studies across the entire spectrum from assessments of micronutrient intake and status to intervention studies to studies of the impact of micronutrients given as supplements or in food. Understanding how much the concentration of certain minerals varies within subjects and between subjects is essential to exploring the effects of these concentrations on infants and determining whether such measurements can be used to assess the impact of specific interventions in the breast feeding maternal-infant dyad (2,3). For example, when a relationship is found between plasma concentrations of a mineral and its concentration in breast milk there is not much reason for concern about the variation around individual measurements. However, when no relationship is found, that may be either because the two are truly unrelated or because there is too much variation around one or both measurements to detect a relationship with one pair of measurements. The paper by Dhonukshe-Rutten et al. (1) concludes that two consecutive sampling days for each woman are necessary to estimate the iron and copper concentration in breast milk, while only one sample per woman is needed for a reliable estimate of zinc concentration. A review of studies published between 1950 and 2000 revealed no consistent relationship between iron and copper concentrations in breast milk and maternal constitutional variables, such as undernutrition, anemia, body iron and copper reserves, stage of lactation, adolescent motherhood, gestational length and infection and environmental variables such as iron and copper intake, supplementation, smoking, vegetarianism and prolonged use of hormonal contraceptives before and during lactation (4). The most recent study on determinants of iron, zinc and copper concentration in breast milk, by Domellöf et al. (5), compared breast milk iron, zinc and copper in Honduran and Swedish mothers. Although they found a higher iron concentration among Swedish mothers than among Honduran mothers and a lower prevalence of iron deficiency among Swedish mothers compared with Honduran mothers, they concluded that the difference in breast milk iron concentration was related to the higher milk volume in Honduran mothers rather than to their lower iron status. This conclusion was based on the fact that after controlling for study site and energy intake from complementary food, there was no relationship between indices of iron status and breast milk iron concentration and on the finding that breast milk iron concentration was not different among anemic and non-anemic Honduran mothers. Although we question the appropriateness of controlling for study site in the analysis because it implicitly means controlling for iron status, the main problem appears to be the very high standard deviations around the means, particularly for iron and copper (and similar in magnitude to the ones found by Dhonukshe-Rutten et al.), which makes it very difficult to detect a relationship with any other variable. Based on their data, Dhonukshe-Rutten et al. (1) recommend that to accurately assess a mother’s breast milk iron and copper concentrations, two samples taken on consecutive days should be evaluated, whether the aim is to determine the relationship of breast milk iron concentration with maternal diet or maternal status or to assess the impact of a particular intervention. Because breast milk iron concentration has been reported to vary from 0.2 to 0.7 mg/L, understanding what it takes to improve the content and understanding how to appropriately assess it in an individual mother is essential. Iron deficiency affects 40% to 45% of children younger than 5 years old in developing countries (6). Newborn infants are born with approximately 75 mg iron/kg body weight, 75% of which is in the form of Journal of Pediatric Gastroenterology and Nutrition 40:120–121 February 2005 Lippincott Williams & Wilkins, Philadelphia