The range of vitamin D intakes required to ensure maintenance of wintertime vitamin D status [as defined by incremental cutoffs of serum 25(OH)D] in the vast majority (>97.5%) of 20-40-y-old adults, considering a variety of sun exposure preferences, is between 7.2 and 41.1 microg/d.

The European Fifth Framework Programme (Contract No. QLK1-CT-2000-00623).

BackgroundRecent European Union regulation requires setting of maximum amount of micronutrients in dietary supplements or foods taking into account the tolerable upper intake level (ULs) established by scientific risk assessment and population reference intakes.ObjectiveTo collect and evaluate recently available data on intakes of selected vitamins and minerals from conventional foods, food supplements and fortified foods in adults and children. Intake of calcium, copper, iodine, iron, magnesium, phosphorus, selenium, zinc, folic acid, niacin and total vitamin A/retinol, B6, D and E was derived from nationally representative surveys in Denmark, Germany, Finland, Ireland, Italy, the Netherlands, Poland, Spain and the United Kingdom. Intake of high consumers, defined as the 95th percentile of each nutrient, was compared to the UL.ResultsFor most nutrients, adults and children generally consume considerably less than the UL with exceptions being retinol, zinc, iodine, copper and magnesium. The major contributor to intakes for all nutrients and in all countries is from foods in the base diet. The patterns of food supplements and voluntary fortification vary widely among countries with food supplements being responsible for the largest differences in total intakes. In the present study, for those countries with data on fortified foods, fortified foods do not significantly contribute to higher intakes for any nutrient. Total nutrient intake expressed as percentage of the UL is generally higher in children than in adults.ConclusionThe risk of excessive intakes is relatively low for the majority of nutrients with a few exceptions. Children are the most vulnerable group as they are more likely to exhibit high intakes relative to the UL. There is a need to develop improved methods for estimating intakes of micronutrients from fortified foods and food supplements in future dietary surveys.

Objective: We applied VDSP protocols to existing ELISA-derived serum 25(OH)D data from the Irish National Adult Nutrition Survey (NANS) as a case-study survey and evaluated their effectiveness by comparison of the protocol-projected estimates with those from a reanalysis of survey serums by using liquid chromatography-tandem mass spectrometry (LC-tandem MS). Design: The VDSP reference system and protocols were applied to ELISA-based serum 25(OH)D data from the representative NANS sample (n = 1118). A reanalysis of 99 stored serums by using standardized LC-tandem MS and resulting regression equations yielded predicted standardized serum 25(OH)D values, which were then compared with LC-tandem MS reanalyzed values for all serums. Results: Year-round prevalence rates for serum 25(OH)D concentrations ,30, ,40, and ,50 nmol/L were 6.5%, 21.9%, and 40.0%, respectively, via original ELISA measurements and 11.4%, 25.3%, and 43.7%, respectively, when VDSP protocols were applied. Differences in estimates at ,30-and ,40-nmol/L thresholds, but not at the ,50-nmol/L threshold, were significant (P , 0.05). A reanalysis of all serums by using LC-tandem MS confirmed prevalence estimates as 11.2%, 27.2%, and 45.0%, respectively. Prevalences of serum 25(OH)D concentrations .125 nmol/L were 1.2%, 0.3%, and 0.6% by means of ELISA, VDSP protocols, and LC-tandem MS, respectively. Conclusion: VDSP protocols hold a major potential for national nutrition and health surveys in terms of the standardization of serum 25(OH)D data.Am J Clin Nutr 2013;97:1235-42.

An in vitro method for the estimation of iron bioavailability was subjected to an interlaboratory trial. The method involved a simulated gastrointestinal digestion using pepsin for the gastric stage followed by pancreatin and bile salts for the intestinal stage. The proportion of iron diffused through a semi‐permeable membrane (molecular mass cut‐off 10 kDa) was used to measure the iron dialysability. An interlaboratory trial between nine laboratories was conducted to evaluate the repeatability and reproducibility of the agreed method. The reproducibility of the method among the participating laboratories was 20–30% and depended on the content of dialysable iron. Several factors contributing to the variation in the in vitro dialysability among laboratories are discussed. The pH adjustment in the intestinal digestion was identified as one of the critical parameters. The present in vitro method was used to evaluate the iron dialysability from three meals. The dialysability data were in reasonable agreement with human absorption data. The usefulness of the in vitro dialysability method is discussed.

To ensure that the vitamin D requirement is met by the vast majority (>97.5%) of adults aged >/=64 y during winter, between 7.9 and 42.8 microg vitamin D/d is required, depending on summer sun exposure and the threshold of adequacy of 25(OH)D. This trial was registered at http://www.controlled-trials.com/ISRCTN20236112 as ISRCTN registration no. ISRCTN20236112.

should be used to assess vitamin D status, as it reflects combined dietary supply and dermal production upon exposure to UV blue (UVB) sunlight (2) . Notwithstanding the importance of on-going discussions with respect to thresholds for serum 25(OH)D that represent adequacy/insufficiency, there is widespread acknowledgement of the presence of vitamin D deficiency in the community and the pressing need to address this deficiency (3) .Taking indicators of bone health, including rickets and osteomalacia, bone mineral density and Ca absorption, for which there was sufficient evidence to provide a reasonable and supportable basis for dietary reference intake (DRI) development, the North American Institute of Medicine (IOM)'s DRI committee for Ca and vitamin D proposed a serum 25(OH)D concentration of 40 nmol/l as the median value above which approximately half the population might meet its vitamin D requirement (and below which half might not) and 50 nmol/l as its estimate of the serum 25(OH)D concentration that would meet the requirement of nearly all (i.e. 97·5 %) normal healthy persons (4) . These serum 25(OH)D concentrations were used to specify estimated average requirement (EAR) values for vitamin D intakes of 400 IU/d (10·0 mg/d) in all age and sex subgroups in the population for more than 1 year, assuming minimal UVB sunlight exposure, and from which RDA values were derived for application to individuals (600 and 800 IU/d (15·0 and 20·0 mg/d) of vitamin D for those aged 1 -70 and 70þ

The susceptibility of beta-LG and sodium caseinate to proteolysis by pepsin and trypsin was investigated using SDS or urea-PAGE. The effects were studied of heat, urea, and 2-mercaptoethanol on proteolysis. Native beta-LG was resistant to hydrolysis by pepsin or trypsin because of its compact globular structure. Heat treatment of beta-LG solutions at 90 to 100 degrees C for 5 or 10 min caused changes in the structure or conformation of the protein that rendered it accessible to pepsin and enhanced the extent of proteolysis by trypsin. The susceptibility of beta-LG to proteolysis by pepsin was markedly increased in the presence of urea (3 to 6 M), and the effect was reversible after removal of urea by dialysis. Proteolysis by trypsin was also increased by the presence of 2% 2-mercaptoethanol. Sodium caseinate was very accessible to pepsin without pretreatment and was extensively hydrolyzed at pH 1 to 5 in the presence of 5 M urea (which prevented the protein from precipitation in the isoelectric region); optimal pH was about 2. The activity of pepsin on sodium caseinate at pH 2 was not significantly affected by urea concentration up to about 8 M. The results indicated that the changes in conformation and structure of beta-LG that were induced by heating, reduction, or urea rendered the protein susceptible to peptic hydrolysis.