Dietary bioactive compounds (vitamin E, carotenoids, polyphenols, vitamin C, Se and Zn) have beneficial effects on skin health. The classical route of administration of active compounds is by topical application direct to the skin, and manufacturers have substantial experience of formulating ingredients in this field. However, the use of functional foods and oral supplements for improving skin condition is increasing. For oral consumption, some dietary components could have an indirect effect on the skin via, for example, secondary messengers. However, in the case of the dietary bioactive compounds considered here, we assume that they must pass down the gastrointestinal tract, cross the intestinal barrier, reach the blood circulation, and then be distributed to the different tissues of the body including the skin. The advantages of this route of administration are that the dietary bioactive compounds are metabolized and then presented to the entire tissue, potentially in an active form. Also, the blood continuously replenishes the skin with these bioactive compounds, which can then be distributed to all skin compartments (i.e. epidermis, dermis, subcutaneous fat and also to sebum). Where known, the distribution and mechanisms of transport of dietary bioactive compounds in skin are presented. Even for compounds that have been studied well in other organs, information on skin is relatively sparse. Gaps in knowledge are identified and suggestions made for future research. The skin is the largest organ in man, consisting of different layers of epidermis and dermis. Its primary physiological function is that of a barrier between the body and the external environment, protecting against mechanical damage, radiation, toxic compounds and micro-organisms. Skin plays a role in the regulation of body temperature and is involved in body water homeostasis.Skin is constantly exposed to pro-oxidant environmental stresses from an array of sources, such as air pollutants, solar UV light, chemical oxidants, micro-organisms, cigarette smoke and ozone (Thiele et al. 1997;Cross et al. 1998). Reactive oxygen species have been implicated in the aetiology of several skin disorders including skin cancer and photoageing (Perchellet & Perchellet, 1989;Dalle & Pathak, 1992;Emerit, 1992;Guyton & Kensler, 1993). These reactive oxygen species are capable of oxidizing lipids, proteins or DNA leading to the formation of oxidized products such as lipid hydroperoxides, protein carbonyls or 8-hydroxyguanosine, respectively (Beehler et al. 1992;Hu & Tappel, 1992;Podda et al. 1998). Reactive oxygen species are generated constantly in skin, and are rapidly neutralized by non-enzymatic and enzymatic antioxidant substances, which prevent their harmful effects and maintain a pro-oxidant-antioxidant balance, resulting in cell and tissue stabilization. If the antioxidant defence is exhausted, cell damage can occur. Known non-enzymatic scavengers of free radicals in human skin are b-carotene, vitamin C and vitamin E, and enzymatic scavengers are Se-depende...

In healthy young women, approximately 50% of the magnesium from magnesium-rich mineral water was absorbed when consumed alone. Magnesium bioavailability from mineral water is enhanced when the water is consumed with a meal, perhaps because of a slower gastrointestinal transit time, the presence of digestion products from the meal, or both. Regular consumption of magnesium-rich mineral water could make a valuable contribution to magnesium requirements.

An adequate mineral supply to preterm infants is essential for normal growth and development. This study aimed to compare the mineral contents of human milk (HM) from healthy mothers of preterm (28–32 weeks) and full term (>37 weeks) infants. Samples were collected weekly for eight weeks for the term group (n = 34) and, biweekly up to 16 weeks for the preterm group (n = 27). Iron, zinc, selenium, copper, iodine, calcium, magnesium, phosphorus, potassium, and sodium were quantitatively analyzed by Inductively Coupled Plasma-Mass Spectrometry. The mineral contents of both HM showed parallel compositional changes over the period of lactation, with occasional significant differences when compared at the same postpartum age. However, when the comparisons were performed at an equivalent postmenstrual age, preterm HM contained less zinc and copper from week 39 to 48 (p < 0.002) and less selenium from week 39 to 44 (p < 0.002) than term HM. This translates into ranges of differences (min–max) of 53% to 78%, 30% to 72%, and 11% to 33% lower for zinc, copper, and selenium, respectively. These data provide comprehensive information on the temporal changes of ten minerals in preterm HM and may help to increase the accuracy of the mineral fortification of milk for preterm consumption.

Context Adequate iodine intake is essential throughout life. Key dietary sources are iodized salt and animal products, but dietary patterns in Europe are changing, for example toward lower salt intake and a more plant-based diet. Objective To review iodine intake (not status) in European populations (adults, children, and pregnant women) to identify at-risk groups and dietary sources. Data sources PubMed, Embase, and Cochrane databases, as well as European national nutrition surveys were searched for data on had iodine intake (from dietary assessment) and sources of iodine, collected after 2006. Data selection In total, 57 studies were included, comprising 22 national surveys and 35 sub-national studies. Iodine intake data were available from national surveys of children aged &lt;10 years (n = 11), 11–17 years (n = 12), and adults (n = 15), but data from pregnancy were only available from sub-national studies. Results Iodine intake data are lacking—only 17 of 45 (38%) European countries had iodine-intake data from national surveys. Iodine intake reported from national surveys was below recommendations for: (1) children aged &lt;10 years in 2 surveys (18%), (2) boys and girls aged 11–17 years in 6 (50%) and 8 (68%) surveys, respectively, and (3) adult men and women in 7 (47%) and 12 (80%) surveys, respectively. In pregnant women, intake was below recommendations except where women were taking iodine-containing supplements. Just 32% of national surveys (n = 7) included iodized salt when estimating iodine intake. Milk, dairy products, fish, and eggs were important contributors to intake in many countries, suggesting limited sources in plant-based diets. Conclusion Results are limited by the challenges of dietary assessment for measuring iodine intake. Future national surveys should include iodine intake. Policy makers should consider dietary sources alongside any iodized salt policies when considering methods for improving population iodine intake. Systematic Review Registration PROSPERO 2017 CRD42017075422.

Background:The double-labeling (DL) method for determining magnesium absorption is less cumbersome than is the fecal monitoring method, which has been used most often, but it has not been validated. Objective: The aim of this study was to compare methods and several sampling protocols for determining magnesium absorption to establish a simple and reliable alternative to the fecal monitoring approach. Fecal monitoring was used as the standard against which the DL methods based on urine data (DLU), plasma data (DLP), and plasma kinetics with the use of a deconvolution analysis (DP) were compared. Design: Six healthy adult men received 70 mg 26 Mg orally and 30 mg 25 Mg intravenously. Multiple blood samples and complete urine and fecal samples were collected over 12 d. Stable-isotope ratios were determined by inductively coupled plasma mass spectrometry. Results: Results from DLU were not significantly different from the fecal monitoring reference value (0.48 ± 0.05; x -± SD) when based on 3-d urine pools from 72 to 144 h (0.54 ± 0.04) and when based on the 24-h urine pools from 48 to 72 h (0.49 ± 0.06), 72 to 96 h (0.51 ± 0.11), and 96 to 120 h (0.50 ± 0.06). Results with the DLP method 72 h after isotope administration also compared well with those with the fecal monitoring method (0.54 ± 0.09). Magnesium absorption was 0.47 ± 0.06 with the DP method, which also agreed with the fecal monitoring value. Conclusions: The DL methods are an alternative to fecal monitoring when applied within the appropriate time intervals. Therefore, DLU-the simplest and least invasive approach-is recommended for determining magnesium absorption.