All tissues are in a constant state of turnover, with a tightly controlled regulation of protein synthesis and breakdown rates. Due to the relative ease of sampling skeletal muscle tissue, basal muscle protein synthesis rates and the protein synthetic responses to various anabolic stimuli have been well defined in human subjects. In contrast, only limited data are available on tissue protein synthesis rates in other organs. Several organs such as the brain, liver and pancreas, show substantially higher (basal) protein synthesis rates when compared to skeletal muscle tissue. Such data suggest that these tissues may also possess a high level of plasticity. It remains to be determined whether protein synthesis rates in these tissues can be modulated by external stimuli. Whole-body protein synthesis rates are highly responsive to protein intake. As the contribution of muscle protein synthesis rates to whole-body protein synthesis rates is relatively small considering the large amount of muscle mass, this suggests that other organ tissues may also be responsive to (protein) feeding. Whole-body protein synthesis rates in the fasted or fed state can be quantified by measuring plasma amino acid kinetics, although this requires the production of intrinsically labelled protein. Protein intake requirements to maximise whole-body protein synthesis may also be determined by the indicator amino acid oxidation technique, but the technique does not allow the assessment of actual protein synthesis and breakdown rates. Both approaches have several other methodological and inferential limitations that will be discussed in detail in this paper.

The Brazilian National School Feeding Program (PNAE) seeks to meet student’s nutritional needs during the period they remain in school. This study aimed to determine the nutritional composition of meals provided in municipal day-care centres serving children of 7–11 months (group A) and 12–36 months (group B) of age and to compare observed values with the PNAE’s and dietary reference intakes’ (DRI) recommendations. This cross-sectional study was conducted in 4 day-care centres in the metropolitan area of Curitiba, Paraná, Brazil, between June and November 2013. Food samples of six daily meals were collected during 20 non-consecutive days, totalling 120 samples. For each meal, average served and consumed portions were submitted for laboratory analysis of moisture, ash, proteins, lipids, carbohydrates, dietary fibre, Na, Ca and Fe and compared with the PNAE’s and DRI’s values. No statistically significant difference was found between age groups (P=0·793) regarding portion sizes and nutritional composition. The same menu was offered to both groups in 95 % of the meals (n 114), although the groups’ nutritional needs were different. For group A, served meals met PNAE’s recommendations for energy, carbohydrates, proteins, Na and Ca content, and consumed portions provided 70 % of the nutritional needs for carbohydrates, proteins and Ca. For group B, served portions complied with the PNAE’s values for proteins, Na and Ca. Proteins and Na reached 70 % of the nutritional needs when consumed food was evaluated. School feeding in day-care centres partially meet PNAE’s guidelines and children’s nutritional requirements, contradicting the primary objective established by the national programme.

There is controversy whether children should have a dietary supply of preformed long-chain polyunsaturated n-3 fatty acids EPA and DHA. The aims of the workshop were to review evidence for a possible benefit of a preformed EPA and/or DHA supply, of data required to set desirable intakes for children aged 2–12 years, and of research priorities. The authors concluded that EPA and DHA intakes per kg body weight may often be low in 2- to 12-year-old children, relative to intakes per kg body weight of breast-fed infants and adult intakes, but reliable data are scarce. Little information is available that increasing dietary intakes of EPA or DHA in children has benefits to physical or mental function or other health endpoints. Studies addressing EPA and DHA intakes and tissue status among groups of children with different dietary habits, and measures of relevant development and health endpoints, are needed for developing potential advice on desirable intakes of EPA and/or DHA in children. At this time it appears prudent to advise that dietary intakes in childhood are consistent with future eating patterns supporting adult health, such as prevention of metabolic disorders and CVD, supporting immune function, and reproductive health. In conclusion, the available information relating dietary EPA and DHA intakes in children aged 2–12 years to growth, development and health is insufficient to derive dietary intake recommendations for EPA and DHA. Adequately designed studies addressing dietary intakes, measures of status and relevant functional or health effects across this age group are needed.

Recommendations for vitamin A intake are based on maintaining liver stores of ≥ 0·070 μmol/g, which is sufficient to maintain normal vision. We propose that higher levels may be required to maintain normal immune function. To test this hypothesis, we conducted an 8-week residential study among thirty-six healthy Bangladeshi men with low vitamin A stores. Subjects were randomised to receive vitamin A (240 mg in four doses) or placebo during study weeks 2 and 3. Vitamin A stores were estimated by isotopic dilution at week 8. Total T-cells, the naive T-cells:memory T-cells ratio and mitogen-induced lymphocyte proliferation were positively and significantly correlated with vitamin A stores (P < 0·05). Mitogen-stimulated IL-2, IL-4 and TNFα increased significantly (P < 0·05) in the vitamin A but not placebo group after supplementation, while IL-10 production was significantly and negatively correlated with vitamin A stores (P < 0·05). Segmented linear regression analysis revealed that naive T-cell counts and T-cell blastogenesis were positively associated with vitamin A stores above but not below 0·070 μmol/g liver. These data show that increasing vitamin A stores above the level that maintains normal vision enhances some measures of T-cell-mediated immunity, suggesting a difference in requirements for maintaining vision and immune function.

From a public health perspective, some of the new insights into folic acid nutrition are of significance. Folate intake recommendations vary under different conditions. Intake of 350 μg is required to maintain plasma homocysteine levels, 650 μg for those with elevated plasma homocysteine, about 400 μg for women planning to become pregnant and 4000 μg for those with history of neural tube defect affected pregnancy. This raises the question whether the folate intake is adequate for the general population, particularly in the vulnerable groups or whether there is a need for scientists to take a fresh view of the requirements, recommended dietary intakes, and consider intervention measures which will have impact on the folate nutritional status. The recommendations should provide a margin of safety to allow for decreased intake, increased requirements, individual variability and bioavailability of natural food folates. The folate intake and nutriture in relation to India and other developing countries needs careful consideration to reduce anemia, neural tube defects and possibly impact on the high incidence of cardiovascular diseases.