In considering the vitamin B-12 fortification of flour, it is important to know who is at risk of vitamin B-12 deficiency and whether those individuals would benefit from flour fortification. This ...article reviews current knowledge of the prevalence and causes of vitamin B-12 deficiency and considers whether fortification would improve the status of deficient subgroups of the population. In large surveys in the United States and the United Kingdom, almost equal to6% of those aged greater-than-or-equal60 y are vitamin B-12 deficient (plasma vitamin B-12 < 148 pmol/L), with the prevalence of deficiency increasing with age. Closer to 20% have marginal status (plasma vitamin B-12: 148-221 pmol/L) in later life. In developing countries, deficiency is much more common, starting in early life and persisting across the life span. Inadequate intake, due to low consumption of animal-source foods, is the main cause of low serum vitamin B-12 in younger adults and likely the main cause in poor populations worldwide; in most studies, serum vitamin B-12 concentration is correlated with intake of this vitamin. In older persons, food-bound cobalamin malabsorption becomes the predominant cause of deficiency, at least in part due to gastric atrophy, but it is likely that most elderly can absorb the vitamin from fortified food. Fortification of flour with vitamin B-12 is likely to improve the status of most persons with low stores of this vitamin. However, intervention studies are still needed to assess efficacy and functional benefits of increasing intake of the amounts likely to be consumed in flour, including in elderly persons with varying degrees of gastric atrophy.
Infants should be exclusively breastfed for the first 6 mo of life. However, maternal deficiency of some micronutrients, conveniently classified as Group I micronutrients during lactation, can result ...in low concentrations in breast milk and subsequent infant deficiency preventable by improving maternal status. This article uses thiamin, riboflavin, vitamin B-6, vitamin B-12, and choline as examples and reviews the evidence for risk of inadequate intakes by infants in the first 6 mo of life. Folate, a Group II micronutrient, is included for comparison. Information is presented on forms and concentrations in human milk, analytical methods, the basis of current recommended intakes for infants and lactating women, and effects of maternal supplementation. From reports of maternal and/or infant deficiency, concentrations in milk were noted as well as any consequences for infant function. These milk values were used to estimate the percent of recommended daily intake that infants fed by a deficient mother could obtain from her milk. Estimates were 60% for thiamin, 53% for riboflavin, 80% for vitamin B-6, 16% for vitamin B-12, and 56% for choline. Lack of data limits the accuracy and generalizability of these conclusions, but the overall picture that emerges is consistent across nutrients and points to an urgent need to improve the information available on breast milk quality.
Overview of Nutrients in Human Milk Dror, Daphna K; Allen, Lindsay H
Advances in nutrition (Bethesda, Md.),
20/May , Letnik:
9, Številka:
suppl_1
Journal Article
Recenzirano
Odprti dostop
The WHO recommends exclusive breastfeeding for the first 6 mo of life to promote optimal infant health and development. Understanding the micro- and macronutrient concentrations of human milk and how ...each nutrient fluctuates with lactational stage, maternal factors, and supplementation is imperative for supporting good breastfeeding practices. Where maternal undernutrition compromises human milk quality, a thorough awareness of the effectiveness of interventions can direct efforts to achieve both maternal and infant nutrient sufficiency. This review of current knowledge covers trends in nutrient concentrations over the course of lactation and describes the influence of maternal intake, status, supplementation, and other factors on human milk concentrations of each nutrient.
This review describes current knowledge of the main causes of vitamin B12 and folate deficiency. The most common explanations for poor B12 status are a low dietary intake of the vitamin (i.e., a low ...intake of animal-source foods) and malabsorption. Although it has long been known that strict vegetarians (vegans) are at risk for vitamin B12 deficiency, evidence now indicates that low intakes of animal-source foods, such as occur in some lacto-ovo vegetarians and many less-industrialized countries, cause vitamin B12 depletion. Malabsorption of the vitamin is most commonly observed as food-bound cobalamin malabsorption due to gastric atrophy in the elderly, and probably as a result of Helicobacter pylori infection. There is growing evidence that gene polymorphisms in transcobalamins affect plasma vitamin B12 concentrations. The primary cause of folate deficiency is low intake of sources rich in the vitamins, such as legumes and leafy vegetables, and the consumption of these foods may explain why folate status can be adequate in relatively poor populations. Lactation and alcoholism also increase the risk of folate deficiency.
Summary Maternal and child undernutrition is highly prevalent in low-income and middle-income countries, resulting in substantial increases in mortality and overall disease burden. In this paper, we ...present new analyses to estimate the effects of the risks related to measures of undernutrition, as well as to suboptimum breastfeeding practices on mortality and disease. We estimated that stunting, severe wasting, and intrauterine growth restriction together were responsible for 2·2 million deaths and 21% of disability-adjusted life-years (DALYs) for children younger than 5 years. Deficiencies of vitamin A and zinc were estimated to be responsible for 0·6 million and 0·4 million deaths, respectively, and a combined 9% of global childhood DALYs. Iron and iodine deficiencies resulted in few child deaths, and combined were responsible for about 0·2% of global childhood DALYs. Iron deficiency as a risk factor for maternal mortality added 115 000 deaths and 0·4% of global total DALYs. Suboptimum breastfeeding was estimated to be responsible for 1·4 million child deaths and 44 million DALYs (10% of DALYs in children younger than 5 years). In an analysis that accounted for co-exposure of these nutrition-related factors, they were together responsible for about 35% of child deaths and 11% of the total global disease burden. The high mortality and disease burden resulting from these nutrition-related factors make a compelling case for the urgent implementation of interventions to reduce their occurrence or ameliorate their consequences.
Despite its contribution to nutrient intake and status, consumption of milk and dairy products by children and adolescents in many countries has waned in recent decades, with a substantial proportion ...of youth failing to meet intake recommendations. Dairy products remain an important dietary source of multiple micronutrients, including calcium, phosphorus, magnesium, zinc, iodine, potassium, vitamin A, vitamin D, vitamin B₁₂, and riboflavin (vitamin B₂). In addition, dairy products provide children with energy, high‐quality protein, and essential and nonessential fatty acids. A review of evidence was conducted to evaluate associations between milk or dairy product intake and health outcomes in children and adolescents. Results suggest a neutral or inverse association between consumption of milk and dairy products in children and adolescents and indicators of adiposity, incidence of dental caries, and hypertension. Available data indicate that dairy products are important for linear growth and bone health during childhood. Additional research – in particular, controlled intervention trials and long‐term prospective cohort studies – is warranted to better understand how dairy intake affects health outcomes in children and adolescents.
Severe vitamin B12 deficiency produces a cluster of neurological symptoms in infants, including irritability, failure to thrive, apathy, anorexia, and developmental regression, which respond ...remarkably rapidly to supplementation. The underlying mechanisms may involve delayed myelination or demyelination of nerves; alteration in the S‐adenosylmethionine:S‐adenosylhomocysteine ratio; imbalance of neurotrophic and neurotoxic cytokines; and/or accumulation of lactate in brain cells. This review summarizes the current knowledge concerning infantile vitamin B12 deficiency, including a pooled analysis of case studies of infants born to mothers with untreated pernicious anemia or a strict vegetarian lifestyle and a discussion of the mechanisms that may underlie the manifestations of deficiency.
This report on vitamin B-12 (B12) is part of the Biomarkers of Nutrition for Development (BOND) Project, which provides state-of-the art information and advice on the selection, use, and ...interpretation of biomarkers of nutrient exposure, status, and function. As with the other 5 reports in this series, which focused on iodine, folate, zinc, iron, and vitamin A, this B12 report was developed with the assistance of an expert panel (BOND B12 EP) and other experts who provided information during a consultation. The experts reviewed the existing literature in depth in order to consolidate existing relevant information on the biology of B12, including known and possible effects of insufficiency, and available and potential biomarkers of status. Unlike the situation for the other 5 nutrients reviewed during the BOND project, there has been relatively little previous attention paid to B12 status and its biomarkers, so this report is a landmark in terms of the consolidation and interpretation of the available information on B12 nutrition. Historically, most focus has been on diagnosis and treatment of clinical symptoms of B12 deficiency, which result primarily from pernicious anemia or strict vegetarianism. More recently, we have become aware of the high prevalence of B12 insufficiency in populations consuming low amounts of animal-source foods, which can be detected with ≥1 serum biomarker but presents the new challenge of identifying functional consequences that may require public health interventions.
Two core nutrient intake reference values (NRVs) are required for assessing the adequacy and safety of nutrient intakes for population groups: the average requirement (AR) and the tolerable upper ...level of intake (UL). Applications of such assessments include providing advice to improve intakes, formulating complementary foods, estimating the amounts of nutrients to be added to fortified foods and monitoring changes in intake, and product labeling at the global, national, or regional level. However, there is a lack of unity across country-level organizations in the methodological approach used to derive NRVs, and ARs and ULs are lacking in many compilations, thus limiting the ability to assess nutrient intakes for their population groups. Because physiological requirements vary little across populations globally, and setting reference values requires determining an acceptable level of uncertainty, it is feasible to adapt current recommendations from different sources to harmonize these core reference values. The objective of this review is to demonstrate an approach for harmonizing the NRVs for ARs (here termed “H-ARs”) and ULs (“H-ULs”) that can be applied on a global scale to assessing intakes across populations. The approach incorporates the framework and terminology recommended by reports from the United Nations University, the National Academies of Sciences, Engineering, and Medicine (NASEM), the Institute of Medicine (IOM), and the European Food Safety Authority (EFSA). After reviewing available alternatives, the proposed harmonized values were selected from standards set by EFSA (for Europe) and the IOM (for the United States and Canada), giving priority to those published most recently. Justifications for the proposed values are presented, along with discussion of their limitations. Ideally, these methods should be further reviewed by an international group of experts. Meanwhile, the H-ARs and H-ULs suggested in this review can be used to assess intakes of populations for many applications in global and regional contexts.
PDF
