Thursday, 18 January 2018

Minerals in the News Vol. 15, No. 10 (October 2017)

Is Nutrient Content and Other Label Information for Prescription Prenatal Supplements Different from Nonprescription Products?

J Acad Nutr Diet. 2017 Sep;117(9):1429-1436. doi: 10.1016/j.jand.2017.04.002. Epub 2017 May 29
Saldanha LG, et al.

Prenatal supplements are often recommended to pregnant women to help meet their nutrient needs. Many products are available, making it difficult to choose a suitable supplement because little is known about their labeling and contents to evaluate their appropriateness.
To determine differences between prescription and nonprescription prenatal supplements available in the United States regarding declared nutrient and nonnutrient ingredients and the presence of dosing and safety-related information.
Using two publicly available databases with information about prenatal supplement products, information from prescription and nonprescription product labels were extracted and evaluated. For the 82 prescription and 132 nonprescription products, declared label amounts of seven vitamins and minerals, docosahexaenoic acid (DHA), the presence of other nonnutrient components, and the presence of key safety and informational elements as identified in two Department of Health and Human Services Office of Inspector General (OIG)'s 2003 reports were compiled and compared.
Compared with nonprescription products, prescription products contained significantly fewer vitamins (9±0.2 vs 11±0.3; P≤0.05) and minerals (4±0.1 vs 8±0.3; P≤0.05). Declared amounts of folic acid were higher in prescription products, whereas vitamin A, vitamin D, iodine, and calcium were higher in the nonprescription products. Amounts of iron, zinc, and DHA were similar. Virtually all products contained levels of one or more nutrients that exceeded the Recommended Dietary Allowances for pregnant and/or lactating women. Product type also influenced ingredients added. Fewer prescription products contained botanical ingredients (6% prescription vs 33% nonprescription) and probiotics (2% prescription vs 8% nonprescription). Only prescription products contained the stool softener docusate sodium.
Our analysis of prenatal supplements indicates that prescription and nonprescription supplements differ in terms of declared composition and nutrient strength, but have labels that are similarly sparse regarding aspects of use such as dosing information.
Interactions of iron with manganese, zinc, chromium, and selenium as related to prophylaxis and treatment of iron deficiency

J Trace Elem Med Biol. 2017 May;41:41-53. doi: 10.1016/j.jtemb.2017.02.005. Epub 2017 Feb 12
Bjørklund G., et al.

(AA) Iron (Fe) deficiency is considered as the most common nutritional deficiency. Iron deficiency is usually associated with low Fe intake, blood loss, diseases, poor absorption, gastrointestinal parasites, or increased physiological demands as in pregnancy. Nutritional Fe deficiency is usually treated with Fe tablets, sometimes with Fe-containing multimineral tablets. Trace element interactions may have a significant impact on Fe status. Existing data demonstrate a tight interaction between manganese (Mn) and Fe, especially in Fe-deficient state. The influence of Mn on Fe homeostasis may be mediated through its influence on Fe absorption, circulating transporters like transferrin, and regulatory proteins. The existing data demonstrate that the influence of zinc (Zn) on Fe status may be related to their competition for metal transporters. Moreover, Zn may be involved in regulation of hepcidin production. At the same time, human data on the interplay between Fe and Zn especially in terms of Fe-deficiency and supplementation are contradictory, demonstrating both positive and negative influence of Zn on Fe status. Numerous data also demonstrate the possibility of competition between Fe and chromium (Cr) for transferrin binding. At the same time, human data on the interaction between these metals are contradictory. Therefore, while managing hypoferremia and Fe-deficiency anemia, it is recommended to assess the level of other trace elements in parallel with indices of Fe homeostasis. It is supposed that simultaneous correction of trace element status in Fe deficiency may help to decrease possible antagonistic or increase synergistic interactions.
New perspectives on the regulation of iron absorption via cellular zinc concentrations in humans

Crit Rev Food Sci Nutr. 2017 Jul 3;57(10):2128-2143. doi: 10.1080/10408398.2015.1050483
Knez M., et al.

(AA) Iron deficiency is the most prevalent nutritional deficiency, affecting more than 30% of the total world's population. It is a major public health problem in many countries around the world. Over the years various methods have been used with an effort to try and control iron-deficiency anemia. However, there has only been a marginal reduction in the global prevalence of anemia. Why is this so? Iron and zinc are essential trace elements for humans. These metals influence the transport and absorption of one another across the enterocytes and hepatocytes, due to similar ionic properties. This paper describes the structure and roles of major iron and zinc transport proteins, clarifies iron-zinc interactions at these sites, and provides a model for the mechanism of these interactions both at the local and systemic level. This review provides evidence that much of the massive extent of iron deficiency anemia in the world may be due to an underlying deficiency of zinc. It explains the reasons for predominance of cellular zinc status in determination of iron/zinc interactions and for the first time thoroughly explains mechanisms by which zinc brings about these changes.
Magnesium in the gynecological practice: a literature review

Magnes Res. 2017 Feb 1;30(1):1-7. doi: 10.1684/mrh.2017.0419
Parazzini F., et al.

(AA) A growing amount of evidence suggests that magnesium deficiency may play an important role in several clinical conditions concerning women health such as premenstrual syndrome, dysmenorrhea, and postmenopausal symptoms. A number of studies highlighted a positive correlation between magnesium administration and relief or prevention of these symptoms, thus suggesting that magnesium supplementation may represent a viable treatment for these conditions. Despite this amount of evidence describing the efficacy of magnesium, few and un-systematize data are available about the pharmacological mechanism of this ion for these conditions. Herein, we review and systematize the available evidence about the use of oral magnesium supplementation in several gynecological conditions and discuss the pharmacological mechanisms that characterize these interventions. The picture that emerges indicates that magnesium supplementation is effective in the prevention of dysmenorrhea, premenstrual syndrome, and menstrual migraine and in the prevention of climacteric symptoms.
Micronutrients during pregnancy and child psychomotor development: Opposite effects of Zinc and Selenium

Environ Res. 2017 Oct;158:583-589. doi: 10.1016/j.envres.2017.06.037. Epub 2017 Jul 14
Polanska K., et al.

(AA) Studies on the impact of micronutrient levels during different pregnancy periods on child psychomotor functions are limited. The aim of this study was to evaluate the association between maternal plasma concentrations of selected micronutrients, such as: copper (Cu), zinc (Zn), selenium (Se), and child neuropsychological development. The study population consisted of 539 mother-child pairs from Polish Mother and Child Cohort (REPRO_PL). The micronutrient levels were measured in each trimester of pregnancy, at delivery and in the cord blood. Psychomotor development was assessed in children at the age of 1 and 2 years using the Bayley Scales of Infant and Toddler Development. The mean plasma Zn, Cu and Se concentrations in the 1st trimester of pregnancy were 0.91±0.27mg/l, 1.98±0.57mg/l and 48.35±10.54μg/l, respectively. There were no statistically significant associations between Cu levels and any of the analyzed domains of child development. A positive association was observed between Se level in the 1st trimester of pregnancy and child language and motor skills (β=0.18, p=0.03 and β=0.25, p=0.005, respectively) at one year of age. Motor score among one-year-old children decreased along with increasing Zn levels in the 1st trimester of pregnancy and in the cord blood (β=-12.07, p=0.003 and β=-6.51, p=0.03, respectively). A similar pattern was observed for the association between Zn level in the 1st trimester of pregnancy and language abilities at one year of age (β=-7.37, p=0.05). Prenatal Zn and Se status was associated with lower and higher child psychomotor abilities, respectively, within the first year of life. Further epidemiological and preclinical studies are necessary to confirm the associations between micronutrient levels and child development as well as to elucidate the underlying mechanisms of their effects.