Iron & Vitamin C

CLINICAL STUDIES ON THE FOLLOWING INGREDIENTS:

Nutrition of women with hair loss problem during the period of menopause

Abstract

During the period of menopause as an effect of changes in hormone status, one of the most common ailments for women is hair loss. Taking into consideration fact that the ingredients of diet contained in various groups of consumed food products are both precursors in steroid hormones synthesis as well as have direct impact on structure, growth and keeping hair in skin integument, this is the reason why nourishing support for women during this period of life as well as during the hair loss therapy is reasonable.

Standard value proteins containing Sulphur amino-acids: cysteine and methionine as precursor to keratin hair protein synthesis are basic element of diet conditioning of hair building. Irreplaceable having impact on keeping hair in skin integument is exogenous L-lysine, mainly present in the inner part of hair root is responsible for hair shape and volume. Fats present in the diet take part in steroid hormones synthesis (from cholesterol) thus have influence on keeping hair in skin integument. Women diet should contain products rich in complex carbohydrates, with low glycemic index and load containing fiber regulating carbohydrate-lipid metabolism of the body. Vitamins also have impact on the state of hair: C vitamin, group B and A vitamins. Minerals which influence hair growth are: Zn, Fe, Cu, Se, Si, Mg and Ca. It is worthwhile to pay closer attention to diet in women who besides hormone changes and undertaken pharmacotherapy are additionally exposed to chronic stress and improperly conducted cosmetic's and hairdresser's treatments.

Source: Goluch-Koniuszy ZS. Nutrition of women with hair loss problem during the period of menopause. Prz Menopauzalny. 2016 Mar;15(1):56-61. doi: 10.5114/pm.2016.58776. Epub 2016 Mar 29. PMID: 27095961; PMCID: PMC4828511.

The Role of Vitamins and Minerals in Hair Loss: A Review

Abstract

People commonly inquire about vitamin and mineral supplementation and diet as a means to prevent or manage dermatological diseases and, in particular, hair loss. Answering these queries is frequently challenging, given the enormous and conflicting evidence that exists on this subject. There are several reasons to suspect a role for micronutrients in non-scarring alopecia. Micronutrients are major elements in the normal hair follicle cycle, playing a role in cellular turnover, a frequent occurrence in the matrix cells in the follicle bulb that are rapidly dividing. Management of alopecia is an essential aspect of clinical dermatology given the prevalence of hair loss and its significant impact on patients’ quality of life. The role of nutrition and diet in treating hair loss represents a dynamic and growing area of inquiry. In this review we summarize the role of vitamins and minerals, such as vitamin A, vitamin B, vitamin C, vitamin D, vitamin E, iron, selenium, and zinc, in non-scarring alopecia. A broad literature search of PubMed and Google Scholar was performed in July 2018 to compile published articles that study the relationship between vitamins and minerals, and hair loss. Micronutrients such as vitamins and minerals play an important, but not entirely clear role in normal hair follicle development and immune cell function. Deficiency of such micronutrients may represent a modifiable risk factor associated with the development, prevention, and treatment of alopecia. Given the role of vitamins and minerals in the hair cycle and immune defense mechanism, large double-blind placebo-controlled trials are required to determine the effect of specific micronutrient supplementation on hair growth in those with both micronutrient deficiency and non-scarring alopecia to establish any association between hair loss and such micronutrient deficiency.

Source: Almohanna HM, Ahmed AA, Tsatalis JP, Tosti A. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatol Ther (Heidelb). 2019 Mar;9(1):51-70. doi: 10.1007/s13555-018-0278-6. Epub 2018 Dec 13. PMID: 30547302; PMCID: PMC6380979.

Iron and cardiovascular health: A review

Abstract

Iron is an essential element for the biological processes of living organisms, including the production of crucial oxygen-carrying proteins, formation of heme enzymes, and playing roles in electron transfer and oxidation–reduction reactions. It plays a significant role in various cardiovascular functions, including bioenergetics, electrical activity, and programmed cell death. Minor deficiencies of iron have been found to have negative impact on cardiovascular function in patients with heart failure (HF). The contractility of human cardiomyocytes is impaired by iron deficiency (ID), which results in reduced mitochondrial function and lower energy production, ultimately leading to cardiac function impairment, contributing to significant morbidity and mortality in patients with HF. This review discusses iron homeostasis within the human body, as well as ID pathophysiology and its role in HF. Focusing on therapeutic approaches including iron supplementation and/or repletion in patients with ID and HF, comparing results from recent clinical trials. Intravenous (IV) iron therapy has shown promising results in treating ID in HF patients. Large, randomized trials and meta-analysis, like Ferinject Assessment in patients with ID and chronic HF, AFFIRM-AHF, IRONMAN, and HEART-FID have demonstrated the efficacy of IV iron supplementation with IV ferric carboxymaltose or IV ferric derisomaltose in reducing hospitalizations and improving quality of life in patients with Heart Failure with reduced ejection fraction (HFrEF), New York Heart Association (NYHA) II–III. However, survival and mortality have demonstrated no improvement during acute exacerbations of HF or in outpatient management. The potential benefits of IV iron across the entire HF spectrum and its interaction with other HF therapies remain areas of interest for further research.

Source: Othon-Martínez D, Fernandez-Betances OA, Málaga-Espinoza BX, Torres-Perez ME, Cobos E, Gutierrez-Martinez C. Iron and cardiovascular health: A review. Journal of Investigative Medicine. 2024;72(8):787-797. doi:10.1177/10815589241268462

Daily iron supplementation for improving anemia, iron status and health in menstruating women

Background: Iron‐deficiency anemia is highly prevalent among non‐pregnant women of reproductive age (menstruating women) worldwide, although the prevalence is highest in lower‐income settings. Iron‐deficiency anemia has been associated with a range of adverse health outcomes, which restitution of iron stores using iron supplementation has been considered likely to resolve. Although there have been many trials reporting effects of iron in non‐pregnant women, these trials have never been synthesised in a systematic review.

Objectives: To establish the evidence for effects of daily supplementation with iron on anemia and iron status, as well as on physical, psychological and neurocognitive health, in menstruating women.

Search methods: In November 2015 we searched CENTRAL, Ovid MEDLINE, EMBASE, and nine other databases, as well as four digital thesis repositories. In addition, we searched the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and reference lists of relevant reviews.

Selection criteria: We included randomised controlled trials (RCTs) and quasi‐RCTs comparing daily oral iron supplementation with or without a cointervention (folic acid or vitamin C), for at least five days per week at any dose, to control or placebo using either individual‐ or cluster‐randomisation. Inclusion criteria were menstruating women (or women aged 12 to 50 years) reporting on predefined primary (anaemia, haemoglobin concentration, iron deficiency, iron‐deficiency anaemia, all‐cause mortality, adverse effects, and cognitive function) or secondary (iron status measured by iron indices, physical exercise performance, psychological health, adherence, anthropometric measures, serum/plasma zinc levels, vitamin A status, and red cell folate) outcomes.

Data collection and analysis: We used the standard methodological procedures of Cochrane.

Main results: The search strategy identified 31,767 records; after screening, 90 full‐text reports were assessed for eligibility. We included 67 trials (from 76 reports), recruiting 8506 women; the number of women included in analyses varied greatly between outcomes, with endpoint haemoglobin concentration being the outcome with the largest number of participants analysed (6861 women). Only 10 studies were considered at low overall risk of bias, with most studies presenting insufficient details about trial quality.

Women receiving iron were significantly less likely to be anaemic at the end of intervention compared to women receiving control (risk ratio (RR) 0.39 (95% confidence interval (CI) 0.25 to 0.60, 10 studies, 3273 women, moderate quality evidence). Women receiving iron had a higher haemoglobin concentration at the end of intervention compared to women receiving control (mean difference (MD) 5.30, 95% CI 4.14 to 6.45, 51 studies, 6861 women, high quality evidence). Women receiving iron had a reduced risk of iron deficiency compared to women receiving control (RR 0.62, 95% CI 0.50 to 0.76, 7 studies, 1088 women, moderate quality evidence). Only one study (55 women) specifically reported iron‐deficiency anaemia and no studies reported mortality. Seven trials recruiting 901 women reported on 'any side effect' and did not identify an overall increased prevalence of side effects from iron supplements (RR 2.14, 95% CI 0.94 to 4.86, low quality evidence). Five studies recruiting 521 women identified an increased prevalence of gastrointestinal side effects in women taking iron (RR 1.99, 95% CI 1.26 to 3.12, low quality evidence). Six studies recruiting 604 women identified an increased prevalence of loose stools/diarrhoea (RR 2.13, 95% CI 1.10, 4.11, high quality evidence); eight studies recruiting 1036 women identified an increased prevalence of hard stools/constipation (RR 2.07, 95% CI 1.35 to 3.17, high quality evidence). Seven studies recruiting 1190 women identified evidence of an increased prevalence of abdominal pain among women randomised to iron (RR 1.55, 95% CI 0.99 to 2.41, low quality evidence). Eight studies recruiting 1214 women did not find any evidence of an increased prevalence of nausea among women randomised to iron (RR 1.19, 95% CI 0.78 to 1.82). Evidence that iron supplementation improves cognitive performance in women is uncertain, as studies could not be meta‐analysed and individual studies reported conflicting results. Iron supplementation improved maximal and submaximal exercise performance, and appears to reduce symptomatic fatigue. Although adherence could not be formally meta‐analysed due to differences in reporting, there was no evident difference in adherence between women randomised to iron and control.

Authors' conclusions: Daily iron supplementation effectively reduces the prevalence of anemia and iron deficiency, raises haemoglobin and iron stores, improves exercise performance and reduces symptomatic fatigue. These benefits come at the expense of increased gastrointestinal symptomatic side effects.

Source: Low MSY, Speedy J, Styles CE, De‐Regil LM, Pasricha SR. Daily iron supplementation for improving anemia, iron status and health in menstruating women. Cochrane Database of Systematic Reviews 2016, Issue 4. Art. No.: CD009747. DOI: 10.1002/14651858.CD009747.pub2. Accessed 18 September 2025.

The effects of oral iron supplementation on cognition in older children and adults: a systematic review and meta-analysis

Background: In observational studies anaemia and iron deficiency are associated with cognitive deficits, suggesting that iron supplementation may improve cognitive function. However, due to the potential for confounding by socio-economic status in observational studies, this needs to be verified in data from randomised controlled trials (RCTs).

Aim: To assess whether iron supplementation improved cognitive domains: concentration, intelligence, memory, psychomotor skills and scholastic achievement.

Methodology: Searches included MEDLINE, EMBASE, PsychINFO, Cochrane CENTRAL and bibliographies (to November 2008). Inclusion, data extraction and validity assessment were duplicated, and the meta-analysis used the standardised mean difference (SMD). Subgrouping, sensitivity analysis, assessment of publication bias and heterogeneity were employed.

Results: Fourteen RCTs of children aged 6+, adolescents and women were included; no RCTs in men or older people were found. Iron supplementation improved attention and concentration irrespective of baseline iron status (SMD 0.59, 95% CI 0.29 to 0.90) without heterogeneity. In anaemic groups supplementation improved intelligence quotient (IQ) by 2.5 points (95% CI 1.24 to 3.76), but had no effect on non-anaemic participants, or on memory, psychomotor skills or scholastic achievement. However, the funnel plot suggested modest publication bias. The limited number of included studies were generally small, short and methodologically weak.

Conclusions: There was some evidence that iron supplementation improved attention, concentration and IQ, but this requires confirmation with well-powered, blinded, independently funded RCTs of at least one year's duration in different age groups including children, adolescents, adults and older people, and across all levels of baseline iron status.

Source: Falkingham, M., Abdelhamid, A., Curtis, P. et al. The effects of oral iron supplementation on cognition in older children and adults: a systematic review and meta-analysis. Nutr J 9, 4 (2010). https://doi.org/10.1186/1475-2891-9-4

Efficacy of iron supplementation on fatigue and physical capacity in non-anaemic iron-deficient adults: a systematic review of randomised controlled trials

Abstract

Objective Iron supplementation in iron-deficiency anemia is standard practice, but the benefits of iron supplementation in iron-deficient non-anaemic (IDNA) individuals remains controversial. Our objective is to identify the effects of iron therapy on fatigue and physical capacity in IDNA adults.

Design Systematic review and meta-analysis of randomised controlled trials (RCTs).

Setting Primary care.

Participants Adults (≥18 years) who were iron deficient but non-anaemic.

Interventions Oral, intramuscular or intravenous iron supplementation; all therapy doses, frequencies and durations were included.

Comparators: Placebo or active therapy.

Results: We identified RCTs in Medline, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index of Nursing and Allied Health, SportDiscus and CAB Abstracts from inception to 31 October 2016. We searched the WHO’s International Clinical Trials Registry Platform for relevant ongoing trials and performed forward searches of included trials and relevant reviews in Web of Science. We assessed internal validity of included trials using the Cochrane Risk of Bias tool and the external validity using the Grading of Recommendations Assessment, Development and Evaluation methodology. From 11 580 citations, we included 18 unique trials and 2 companion papers enrolling 1170 patients. Using a Mantel-Haenszel random-effects model, iron supplementation was associated with reduced self-reported fatigue (standardised mean difference (SMD) −0.38; 95% CI −0.52 to −0.23; I2 0%; 4 trials; 714 participants) but was not associated with differences in objective measures of physical capacity, including maximal oxygen consumption (SMD 0.11; 95% CI −0.15 to 0.37; I2 0%; 9 trials; 235 participants) and timed methods of exercise testing. Iron supplementation significantly increased serum haemoglobin concentration (MD 4.01 g/L; 95% CI 1.22 to 6.81; I2 48%; 12 trials; 298 participants) and serum ferritin (MD 9.23 µmol/L; 95% CI 6.48 to 11.97; I2 58%; 14 trials; 616 participants).

Conclusion: In IDNA adults, iron supplementation is associated with reduced subjective measures of fatigue but not with objective improvements in physical capacity. Given the global prevalence of both iron deficiency and fatigue, patients and practitioners could consider consumption of iron-rich foods or iron supplementation to improve symptoms of fatigue in the absence of documented anaemia.

Source: Houston BL, Hurrie D, Graham J, et al. Efficacy of iron supplementation on fatigue and physical capacity in non-anaemic iron-deficient adults: a systematic review of randomised controlled trialsBMJ Open 2018;8:e019240. doi: 10.1136/bmjopen-2017-019240

Iron supplementation maintains ventilatory threshold and improves energetic efficiency in iron-deficient nonanemic athletes

Abstract

Objective: To determine the effect of iron supplementation on iron status and endurance capacity.

Design: Randomized, double-blind iron supplementation.

Setting: University of Missouri-Columbia and surrounding community.

Subjects: Twenty iron-deficient (serum ferritin, sFer<16 μg/l; serum transferrin receptor, sTfR>8.0 mg/l; or sTfR/log sFer index >4.5), nonanemic (hemoglobin, Hb>120 g/l, women; >130 g/l, men) men and women (18–41 years) were recruited via fliers and newspaper advertisements; 20 of 31 eligible subjects participated.

Interventions: A 30 mg measure of elemental iron as ferrous sulfate or placebo daily for 6 weeks.

Results: Dietary iron intake and physical activity did not differ between groups before or after supplementation. Iron supplementation significantly increased sFer compared to placebo (P=0.01), but did not affect Hb or hematocrit. Iron supplementation prevented the decline in ventilatory threshold (VT) observed in the placebo group from pre- to post-supplementation (P=0.01); this effect was greater in individuals with lower sFer before intervention (P<0.05). Changes in sFer from pre- to post-treatment were positively correlated with changes in VT (P=0.03), independent of supplementation. The iron group significantly increased gross energetic efficiency during the submaximal test (P=0.04). Changes in sFer were negatively correlated with changes in average respiratory exchange ratio during the submaximal test (P<0.05).

Conclusions: Iron supplementation significantly improves iron status and endurance capacity in iron-deficient, nonanemic trained male and female subjects.

Source: Hinton, P., Sinclair, L. Iron supplementation maintains ventilatory threshold and improves energetic efficiency in iron-deficient nonanemic athletes. Eur J Clin Nutr 61, 30–39 (2007). https://doi.org/10.1038/sj.ejcn.1602479

Iron Supplementation Improves Energetic Efficiency in Iron-Depleted Female Rowers

Abstract

Purpose: Studies in both animals and humans show a relationship between iron depletion without anemia (IDNA) and physical performance. Compared with their sedentary counterparts, female endurance athletes are at greater risk of IDNA, and consequences relevant to endurance athletes include reduced work capacity and energetic efficiency (EF). We conducted a randomized placebo-controlled trial to investigate the effects of iron (Fe) supplementation on Fe status and performance in nonanemic female rowers during training.

Methods: At the beginning of a training season, 40 rowers were randomized to receive either 100 mg·d⁻¹ FeSO4 (n = 21) or placebo (n = 19) using a double-blind design. Thirty-one (n = 15 Fe, 16 placebo) completed the 6-wk trial. Fe status (hemoglobin, serum ferritin, soluble transferrin receptor), body composition, and laboratory tests of physical performance (4-km time trial, V˙O2peak, energetic EF, and blood lactate) were assessed at baseline and after training.

Results: Rowers in both groups increased their fat-free mass (P < 0.001) and V˙O2peak (P < 0.001) after training. Multiple regression analyses revealed improvements in Fe stores (serum ferritin) in the Fe treatment group after controlling for baseline Fe stores (P = 0.07). Rowers in the Fe group had slower lactate response during the first half of the time trial and after 5 min of recovery (P = 0.05) and showed greater improvements in energy expenditure (P = 0.01 for group-by time) and energetic EF compared with placebo (P = 0.03 for group-by time).

Conclusions: Female rowers with depleted Fe stores who consumed supplemental Fe during training improved their Fe status and energetic EF during endurance exercise. These results are important for endurance athletes whose dietary patterns and physical training increase their risk of IDNA and suggest that Fe supplementation may maximize the benefits of endurance training.

Source: DELLAVALLE, DIANE M.1; HAAS, JERE D.2. Iron Supplementation Improves Energetic Efficiency in Iron-Depleted Female Rowers. Medicine & Science in Sports & Exercise 46(6):p 1204-1215, June 2014. | DOI: 10.1249/MSS.0000000000000208

Iron treatment normalizes cognitive functioning in young women

Background: Evidence suggests that brain iron deficiency at any time in life may disrupt metabolic processes and subsequently change cognitive and behavioral functioning. Women of reproductive age are among those most vulnerable to iron deficiency and may be at high risk for cognitive alterations due to iron deficiency.

Objective: We aimed to examine the relation between iron status and cognitive abilities in young women.

Design: A blinded, placebo-controlled, stratified intervention study was conducted in women aged 18–35 y of varied iron status who were randomly assigned to receive iron supplements or a placebo. Cognition was assessed by using 8 cognitive performance tasks (from Detterman's Cognitive Abilities Test) at baseline (n= 149) and after 16 wk of treatment (n= 113).

Results: At baseline, the iron-sufficient women (n= 42) performed better on cognitive tasks (P= 0.011) and completed them faster (P= 0.038) than did the women with iron deficiency anemia (n= 34). Factors representing performance accuracy and the time needed to complete the tasks by the iron-deficient but nonanemic women (n= 73) were intermediate between the 2 extremes of iron status. After treatment, a significant improvement in serum ferritin was associated with a 5–7-fold improvement in cognitive performance, whereas a significant improvement in hemoglobin was related to improved speed in completing the cognitive tasks.

Conclusions: Iron status is a significant factor in cognitive performance in women of reproductive age. Severity of anemia primarily affects processing speed, and severity of iron deficiency affects accuracy of cognitive function over a broad range of tasks. Thus, the effects of iron deficiency on cognition are not limited to the developing brain.

Source: Laura E Murray-Kolb, John L Beard, Iron treatment normalizes cognitive functioning in young women,The American Journal of Clinical Nutrition, Volume 85, Issue 3, 2007, Pages 778-787, ISSN 0002-9165, https://doi.org/10.1093/ajcn/85.3.778

Iron deficiency and fatigue in inflammatory bowel disease: A systematic review

Background: It is unclear what impact iron deficiency has on fatigue in people with inflammatory bowel disease (IBD). This systematic review examined the evidence of whether iron deficiency, with or without anaemia, was associated with fatigue in IBD. Fatigue is a common symptom in patients with IBD that can be difficult to manage and treat. A greater understanding of the role and contribution of iron deficiency to fatigue may help improve the management of this condition.

Methods: The databases searched were MEDLINE, OVID, CINAHL and Web of Science. Inclusion criteria were studies measuring iron status for iron deficiency (ID) and patient-reported outcome measures (PROMs) for fatigue in patients with IBD of any level of disease activity. Assessment of bias was conducted using the Newcastle Ottawa Scale. Studies were grouped for syntheses according to whether exposure was iron deficiency without anaemia (IDWA) or ID regardless of haemoglobin level.

Results: Two hundred and eighty-five individual database results were identified and screened; 32 complete records were reviewed, from which seven studies with 1425 individuals were deemed eligible for inclusion in the results synthesis. Considerable variation in the methods and statistical analysis used to investigate the relationship between ID and fatigue prevented any quantitative synthesis. Studies varied by population disease activity levels, approaches used to define ID and PROMs used to measure fatigue. Three studies directly compared fatigue scores in IDWA to those not iron deficient, two of which showed patients with IDWA had significantly lower fatigue scores. Four studies used ID irrespective of anaemia as the exposure and reported mixed results on fatigue, with only one study reporting a higher prevalence of fatigue in the ID group.

Conclusions: There was marked heterogeneity between studies in this review. Two studies found evidence of a slight increase in fatigue levels in patients with IDWA. Though this does not explain all fatigue in patients with IBD, iron replacement should be considered to improve fatigue in iron-deficient patients.

Source: Sartain, S., Al-Ezairej, M., McDonnell, M., Westoby, C., Katarachia, V., Wootton, S.A. and Cummings, J.F., 2025. Iron deficiency and fatigue in inflammatory bowel disease: A systematic review. Plos one, 20(1), p.e0304293.

Iron deficiency without anemia is a potential cause of fatigue: meta-analyses of randomised controlled trials and cross-sectional studies

Abstract

Fe deficiency is a prevalent nutritional disease, and fatigue is a common complaint in the general and patient population. The association between Fe deficiency without anaemia (IDNA) and fatigue is unclear. Here, we performed a meta-analysis to evaluate the therapeutic effect of Fe on fatigue in patients with IDNA and the association between IDNA and fatigue in the population. Articles from the PubMed database up to 19 January 2016 were systematically searched. A total of six relevant randomised controlled trials (RCT) and six relevant cross-sectional studies were identified. All outcomes were converted into effect sizes. In the meta-analysis of the six RCT, we identified a significant therapeutic effect of Fe in fatigue patients with IDNA (pooled effect size 0·33; 95 % CI 0·17, 0·48; I 2=0·0 %; P<0·0001). A sensitivity analysis found that the overall results (i.e. significant association) were robust. In the meta-analysis of the six cross-sectional studies, the association between IDNA and fatigue was not significant (pooled effect size 0·10; 95 % CI −0·11, 0·31; I 2=57·4 %; P=0·362). A sensitivity analysis found that the overall results (i.e. no significant association) were not robust; removal of one study made the outcomes significant. These meta-analyses suggest that improving Fe status may decrease fatigue. Further research is necessary to identify diagnostic criteria for selecting fatigue patients who might benefit from Fe therapy and to assess the prevalence of IDNA with fatigue in the general population.

Source: Yokoi K, Konomi A. Iron deficiency without anemia is a potential cause of fatigue: meta-analyses of randomised controlled trials and cross-sectional studies. British Journal of Nutrition. 2017;117(10):1422-1431. doi:10.1017/S0007114517001349

Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial

Background: The true benefit of iron supplementation for nonanemic menstruating women with fatigue is unknown. We studied the effect of oral iron therapy on fatigue and quality of life, as well as on hemoglobin, ferritin and soluble transferrin receptor levels, in nonanemic iron-deficient women with unexplained fatigue.

Methods: We performed a multicentre, parallel, randomized controlled, closed-label, observer-blinded trial. We recruited from the practices of 44 primary care physicians in France from March to July 2006. We randomly assigned 198 women aged 18–53 years who complained of fatigue and who had a ferritin level of less than 50 ug/L and hemoglobin greater than 12.0 g/dL to receive either oral ferrous sulfate (80 mg of elemental iron daily; n = 102) or placebo (n = 96) for 12 weeks. The primary outcome was fatigue as measured on the Current and Past Psychological Scale. Biological markers were measured at 6 and 12 weeks.

Results: The mean score on the Current and Past Psychological Scale for fatigue decreased by 47.7% in the iron group and by 28.8% in the placebo group (difference –18.9%, 95% CI −34.5 to −3.2; p = 0.02), but there were no significant effects on quality of life (p = 0.2), depression (p = 0.97) or anxiety (p = 0.5). Compared with placebo, iron supplementation increased hemoglobin (0.32 g/dL; p = 0.002) and ferritin (11.4 μg/L; p < 0.001) and decreased soluble transferrin receptor (−0.54 mg/L; p < 0.001) at 12 weeks.

Source: Paul Vaucher, Pierre-Louis Druais, Sophie Waldvogel and Bernard Favrat

CMAJ August 07, 2012 184 (11) 1247-1254; DOI: https://doi.org/10.1503/cmaj.110950

Iron Absorption: Factors, Limitations, and Improvement Methods

Abstract

Iron is an essential element for human life since it participates in many functions in the human body, including oxygen transport, immunity, cell division and differentiation, and energy metabolism. Iron homeostasis is mainly controlled by intestinal absorption because iron does not have active excretory mechanisms for humans. Thus, efficient intestinal iron bioavailability is essential to reduce the risk of iron deficiency anemia. There are two forms of iron, heme and nonheme, found in foods. The average daily dietary iron intake is 10 to 15 mg in humans since only 1 to 2 mg is absorbed through the intestinal system. Nutrient–nutrient interactions may play a role in dietary intestinal iron absorption. Dietary inhibitors such as calcium, phytates, polyphenols and enhancers such as ascorbic acid and proteins mainly influence iron bioavailability. Numerous studies have been carried out for years to enhance iron bioavailability and combat iron deficiency. In addition to traditional methods, innovative techniques are being developed day by day to enhance iron bioavailability. This review will provide information about iron bioavailability, factors affecting absorption, iron deficiency, and recent studies on improving iron bioavailability.

Source: Piskin E, Cianciosi D, Gulec S, Tomas M, Capanoglu E. Iron Absorption: Factors, Limitations, and Improvement Methods. ACS Omega. 2022 Jun 10;7(24):20441-20456. doi: 10.1021/acsomega.2c01833. PMID: 35755397; PMCID: PMC9219084.

The Regulation of Dietary Iron Bioavailability by Vitamin C: A Systematic Review and Meta-Analysis

Abstract

Iron deficiency is the most common nutritional deficiency worldwide, in part due to the inherent low bioavailability of dietary iron⁽Reference Camaschella ¹ ⁾. Although dietary components such as vitamin C have been demonstrated to influence iron bioavailability, with the discovery of hepicidin as the hormone central regulator of iron homeostasis⁽Reference Ganz ² ⁾, their significance has been questioned. Specifically, the Scientific Advisory Committee in the UK has stated that only the consumption of a healthy balanced diet is required for adequate iron status and the role of dietary enhancers is minimal⁽ ³ ⁾. Therefore, the aims of this systematic review and meta-analysis were to determine the effect of vitamin C on nonheme iron absorption and the effects of long term supplementation on iron status.

The review was conducted by independent reviewers in accordance with PRISMA guidelines and is registered at Prospero (CRD42014010453). Medline, Scopus and Cochrane databases were searched from inception through to December 31^st 2016, with a basic search strategy of “(iron OR ferritin OR haemoglobin) AND (ascorbic acid OR ascorbate OR vitamin C)”. Short-term (<4 weeks) and long-term trials (>4 weeks) reporting measures of iron absorption from isotopically labelled iron meals with and without vitamin C or changes to biomarkers of iron status with vitamin C supplementation in healthy adults were included. Meta-analyses were executed in Review Manager 5 software (version 5.3).

From a total of 4830 identified records, 26 studies (20 short-term, 6 long-term) were included in qualitative synthesis and 22 were included in the meta-analysis (3 excluded as reported arithmetic not geometric means, 1 excluded for not reporting variance). All of the short-term studies were a 16-day crossover design, where the same iron test meals were labelled with different isotopes and consumed on consecutive mornings with and without ascorbic acid; with washout in between. The combined pooled effects showed a highly significant increase in % iron absorption when ascorbic acid was added to test meals and the l² statistic quantifying the level of heterogeneity, indicated a very low level of inconsistency (MD: 5·87; 95 % CI 4·43, 7·31; P = 0·00001; n = 315 total study participants; l² = 14 %).

The effect of long-term ascorbic acid supplementation on haemoglobin status was assessed in 5 studies, arranged in descending order of haemoglobin (Hb) level (g/L) which ranged from 146 g/L-101 g/L (Fig. 1). These data show ascorbic acid supplementation increased haemoglobin value levels from baseline to follow-up significantly, (MD: 8·26; 95 % CI 3·00, 13·53; P = 0·002; n = 118 total study participants; l² = 58 %), with a moderate level of inconsistency between studies.

Source: Heffernan A, Evans C, Holmes M, Moore JB. The Regulation of Dietary Iron Bioavailability by Vitamin C: A Systematic Review and Meta-Analysis. Proceedings of the Nutrition Society. 2017;76(OCE4):E182. doi:10.1017/S0029665117003445

Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial

Source: Vaucher P, Druais PL, Waldvogel S, Favrat B. Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial. CMAJ. 2012 Aug 7;184(11):1247-54. doi: 10.1503/cmaj.110950. Epub 2012 Jul 9. PMID: 22777991; PMCID: PMC3414597.

Iron & Vitamin C

CLINICAL STUDIES ON THE FOLLOWING INGREDIENTS:

Nutrition of women with hair loss problem during the period of menopause

Abstract

The Role of Vitamins and Minerals in Hair Loss: A Review

Abstract

Iron and cardiovascular health: A review

Abstract

Daily iron supplementation for improving anemia, iron status and health in menstruating women

The effects of oral iron supplementation on cognition in older children and adults: a systematic review and meta-analysis

Efficacy of iron supplementation on fatigue and physical capacity in non-anaemic iron-deficient adults: a systematic review of randomised controlled trials

Abstract

Iron supplementation maintains ventilatory threshold and improves energetic efficiency in iron-deficient nonanemic athletes

Abstract

Iron Supplementation Improves Energetic Efficiency in Iron-Depleted Female Rowers

Abstract

Iron treatment normalizes cognitive functioning in young women

Iron deficiency and fatigue in inflammatory bowel disease: A systematic review

Iron deficiency without anemia is a potential cause of fatigue: meta-analyses of randomised controlled trials and cross-sectional studies

Abstract

Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial

Iron Absorption: Factors, Limitations, and Improvement Methods

The Regulation of Dietary Iron Bioavailability by Vitamin C: A Systematic Review and Meta-Analysis

Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial

References: