Iron Status at Age 6 Months in Colombian Infants Exclusively Breast-fed for 4-5 Versus 6 Months.

BACKGROUND: The optimal age for introducing complementary feeding to breast-fed infants may differ depending on the setting. Prolonged exclusive breastfeeding (EBF) protects against infection but may increase the risk of iron deficiency (ID)/anaemia (IDA) in vulnerable infants. AIM: To compare haemoglobin (Hb), serum ferritin (SF)), anaemia (Hb  2500 g), all EBF for ≥4 months. RESULTS: 108 infants (54% boys) were recruited; 46% EBF for 4-5mo, 54% EBF at 6mo. Prevalence of anaemia, ID and IDA was 20%, 10% and 5%, with no significant difference between EBF4-5 and EBF6 groups. In multivariate models, anaemia/ID were predicted by greater weight gain from 0-6 mo, and anaemia also by caesarean delivery; Hb was lower in infants with higher intake of cows' milk; SF was lower in boys and those with greater weight gain. EBF4-5 versus EBF6 was not a significant predictor of any outcome. CONCLUSION: Anaemia and ID were common at 6 months but were not affected by EBF for 4-5 versus 6 months, suggesting 6 months EBF is safe in this population. However, further research is required to examine effects on later iron status. The findings highlight the need to emphasise avoidance of cow's milk before 12 months

Adaptation of New Colombian Food-based Complementary Feeding Recommendations using Linear Programming.

To use Linear Programming (LP) analyses to adapt New Complementary Feeding Guidelines (NCFg) designed for infants aged 6-12 month (m) living in poor socioeconomic circumstances in Bogota to ensure dietary adequacy for young children aged 12-23 m. A secondary data analysis was performed using dietary and anthropometric data collected from 12 m old infants (n = 72) participating in a randomised controlled trial. LP analyses were performed to identify nutrients whose requirements were difficult to achieve using local foods as consumed; and to test and compare the NCFg and alternative food-based recommendations (FBRs) on the basis of dietary adequacy, for 11 micronutrients, at the population level. Thiamine recommended nutrient intakes for these young children could not be achieved given local foods as consumed. NCFg focusing only on meat, fruits, vegetables and breast milk ensured dietary adequacy at the population level for only 4 micronutrients, increasing to 8/11 modelled micronutrients when the FBRs promoted legumes, dairy, vitamin-A rich vegetables and chicken giblets. None of the FBRs tested ensured population-level dietary adequacy for thiamine, niacin and iron unless a fortified infant food was recommended. This study demonstrated the value of using LP to adapt NCFg for a different age group than the one for which they were designed. Our analyses suggest that to ensure dietary adequacy for 12-23 m olds these adaptions should include legumes, dairy products, vitamin A rich vegetables, organ meat and a fortified food

Evolution by flight and fight: diverse mechanisms of adaptation by actively motile microbes

Evolutionary adaptation can be achieved by mechanisms accessible to all organisms, including faster growth and interference competition, but self-generated motility offers additional possibilities. We tested whether 55 populations of the bacterium Myxococcus xanthus that underwent selection for increased fitness at the leading edge of swarming colonies adapted by swarming faster toward unused resources or by other means. Populations adapted greatly but diversified markedly in both swarming phenotypes and apparent mechanisms of adaptation. Intriguingly, although many adapted populations swarm intrinsically faster than their ancestors, numerous others do not. Some populations evolved interference competition toward their ancestors, whereas others gained the ability to facultatively increase swarming rate specifically upon direct interaction with ancestral competitors. Our results both highlight the diverse range of mechanisms by which actively motile organisms can adapt evolutionarily and help to explain the high levels of swarming-phenotype diversity found in local soil populations of M. xanthus