The effect of vitamin B12 and folic acid supplementation on routine haematological parameters in older people: an individual participant data meta-analysis

Vitamin B12 is associated negatively with anemia in older Chinese adults with a low dietary diversity level: evidence from the Healthy Ageing and Biomarkers Cohort Study (HABCS)

OBJECTIVE

The associations between plasma vitamin B12 level and anemia under different dietary patterns in elderly Chinese people are poorly understood. We aimed to examine the associations between plasma vitamin B12 levels and anemia under different dietary patterns in adults aged 65 years and older in nine longevity areas in China.

METHODS

A total of 2405 older adults completed a food frequency questionnaire at the same time as a face-to-face interview. The dietary diversity score (DDS) was assessed based on the food frequency questionnaire, with the low DDS group referring to participants with a DDS score ≤ 4 points. Vitamin B12 levels were divided into two groups of high (>295 pg/mL) and low (≤ 295 pg/mL) with the median used as the cut-off point. Sub-analyses were also performed on older adults divided into tertiles of vitamin B12 levels: low (< 277 pg/mL), medium (277-375 pg/mL) and high (> 375 pg/mL) to study the association of these levels with anemia.

RESULTS

Six hundred ninety-five (28.89%) of these people were diagnosed with anemia and had a mean age of 89.3 years. Higher vitamin B12 levels were associated with a decreased risk of anemia (multi-adjusted OR, 0.59, [95% CI, 0.45 ~ 0.77] P < 0.001) in older adults with a low DDS, whereas no significant association between vitamin B12 levels and anemia was found in older adults with a high DDS in a full-model after adjustment for various confounding factors (multi-adjusted OR, 0.88, [95% CI, 0.65 ~ 1.19], P = 0.41).

CONCLUSION

The relationship between vitamin B12 levels and the prevalence of anemia was significant only when the level of dietary diversity in the older adults was relatively low. The dietary structure of the population should be taken into consideration in combination in order to effectively improve anemia status by supplementing vitamin B12.

Nutrition-specific interventions for preventing and controlling anaemia throughout the life cycle: an overview of systematic reviews

BACKGROUND

Anaemia is a prevalent health problem worldwide. Some types are preventable or controllable with iron supplementation (pills or drops), fortification (sprinkles or powders containing iron added to food) or improvements to dietary diversity and quality (e.g. education or counselling).

OBJECTIVES

To summarise the evidence from systematic reviews regarding the benefits or harms of nutrition-specific interventions for preventing and controlling anaemia in anaemic or non-anaemic, apparently healthy populations throughout the life cycle.

METHODS

In August 2020, we searched MEDLINE, Embase and 10 other databases for systematic reviews of randomised controlled trials (RCTs) in anaemic or non-anaemic, apparently healthy populations. We followed standard Cochrane methodology, extracting GRADE ratings where provided. The primary outcomes were haemoglobin (Hb) concentration, anaemia, and iron deficiency anaemia (IDA); secondary outcomes were iron deficiency (ID), severe anaemia and adverse effects (e.g. diarrhoea, vomiting).

MAIN RESULTS

We included 75 systematic reviews, 33 of which provided GRADE assessments; these varied between high and very low. Infants (6 to 23 months; 13 reviews) Iron supplementation increased Hb levels and reduced the risk of anaemia and IDA in two reviews. Iron fortification of milk or cereals, multiple-micronutrient powder (MMNP), home fortification of complementary foods, and supplementary feeding increased Hb levels and reduced the risk of anaemia in six reviews. In one review, lipid-based nutrient supplementation (LNS) reduced the risk of anaemia. In another, caterpillar cereal increased Hb levels and IDA prevalence. Food-based strategies (red meat and fortified cow's milk, beef) showed no evidence of a difference (1 review). Preschool and school-aged children (2 to 10 years; 8 reviews) Daily or intermittent iron supplementation increased Hb levels and reduced the risk of anaemia and ID in two reviews. One review found no evidence of difference in Hb levels, but an increased risk of anaemia and ID for the intermittent regime. All suggested that zinc plus iron supplementation versus zinc alone, multiple-micronutrient (MMN)-fortified beverage versus control, and point-of-use fortification of food with iron-containing micronutrient powder (MNP) versus placebo or no intervention may increase Hb levels and reduce the risk of anaemia and ID. Fortified dairy products and cereal food showed no evidence of a difference on the incidence of anaemia (1 review). Adolescent children (11 to 18 years; 4 reviews) Compared with no supplementation or placebo, five types of iron supplementation may increase Hb levels and reduce the risk of anaemia (3 reviews). One review on prevention found no evidence of a difference in anaemia incidence on iron supplementation with or without folic acid, but Hb levels increased. Another suggested that nutritional supplementation and counselling reduced IDA. One review comparing MMN fortification with no fortification observed no evidence of a difference in Hb levels. Non-pregnant women of reproductive age (19 to 49 years; 5 reviews) Two reviews suggested that iron therapy (oral, intravenous (IV), intramuscular (IM)) increased Hb levels; one showed that iron folic acid supplementation reduced anaemia incidence; and another that daily iron supplementation with or without folic acid or vitamin C increased Hb levels and reduced the risk of anaemia and ID. No review reported interventions related to fortification or dietary diversity and quality. Pregnant women of reproductive age (15 to 49 years; 23 reviews) One review apiece suggested that: daily iron supplementation with or without folic acid increased Hb levels in the third trimester or at delivery and in the postpartum period, and reduced the risk of anaemia, IDA and ID in the third trimester or at delivery; intermittent iron supplementation had no effect on Hb levels and IDA, but increased the risk of anaemia at or near term and ID, and reduced the risk of side effects; vitamin A supplementation alone versus placebo, no intervention or other micronutrient might increase maternal Hb levels and reduce the risk of maternal anaemia; MMN with iron and folic acid versus placebo reduced the risk of anaemia; supplementation with oral bovine lactoferrin versus oral ferrous iron preparations increased Hb levels and reduced gastrointestinal side effects; MNP for point-of-use fortification of food versus iron and folic acid supplementation might decrease Hb levels at 32 weeks' gestation and increase the risk of anaemia; and LNS versus iron or folic acid and MMN increased the risk of anaemia. Mixed population (all ages; 22 reviews) Iron supplementation versus placebo or control increased Hb levels in healthy children, adults, and elderly people (4 reviews). Hb levels appeared to increase and risk of anaemia and ID decrease in two reviews investigating MMN fortification versus placebo or no treatment, iron fortified flour versus control, double fortified salt versus iodine only fortified salt, and rice fortification with iron alone or in combination with other micronutrients versus unfortified rice or no intervention. Each review suggested that fortified versus non-fortified condiments or noodles, fortified (sodium iron ethylenediaminetetraacetate; NaFeEDTA) versus non-fortified soy sauce, and double-fortified salt versus control salt may increase Hb concentration and reduce the risk of anaemia. One review indicated that Hb levels increased for children who were anaemic or had IDA and received iron supplementation, and decreased for those who received dietary interventions. Another assessed the effects of foods prepared in iron pots, and found higher Hb levels in children with low-risk malaria status in two trials, but no difference when comparing food prepared in non-cast iron pots in a high-risk malaria endemicity mixed population. There was no evidence of a difference for adverse effects. Anaemia and malaria prevalence were rarely reported. No review focused on women aged 50 to 65 years plus or men (19 to 65 years plus).

AUTHORS' CONCLUSIONS

Compared to no treatment, daily iron supplementation may increase Hb levels and reduce the risk of anaemia and IDA in infants, preschool and school-aged children and pregnant and non-pregnant women. Iron fortification of foods in infants and use of iron pots with children may have prophylactic benefits for malaria endemicity low-risk populations. In any age group, only a limited number of reviews assessed interventions to improve dietary diversity and quality. Future trials should assess the effects of these types of interventions, and consider the requirements of different populations.

The effects of single and a combination of determinants of anaemia in the very old: results from the TULIPS consortium

Background and objectives

Nutritional deficiencies, renal impairment and chronic inflammation are commonly mentioned determinants of anaemia. The aim of this study was to investigate the effects of these determinants, singly and in combination, on anaemia in the very old.

Method

The TULIPS Consortium consists of four population-based studies in oldest-old individuals: Leiden 85-plus Study, LiLACS NZ, Newcastle 85+ study, and TOOTH. Five selected determinants (iron, vitamin B12, and folate deficiency; low estimated glomerular filtration rate (eGFR); and high C-reactive protein (CRP)) were summed. This sum score was used to investigate the association with the presence and onset of anaemia (WHO definition). The individual study results were pooled using random-effects models.

Results

In the 2216 participants (59% female, 30% anaemia) at baseline, iron deficiency, low eGFR and high CRP were individually associated with the presence of anaemia. Low eGFR and high CRP were individually associated with the onset of anaemia.

In the cross-sectional analyses, an increase per additional determinant (adjusted OR 2.10 (95% CI 1.85–2.38)) and a combination of ≥2 determinants (OR 3.44 (95% CI 2.70–4.38)) were associated with the presence of anaemia. In the prospective analyses, an increase per additional determinant (adjusted HR 1.46 (95% CI 1.24–1.71)) and the presence of ≥2 determinants (HR 1.95 (95% CI 1.40–2.71)) were associated with the onset of anaemia.

Conclusion

Very old adults with a combination of determinants of anaemia have a higher risk of having, and of developing, anaemia. Further research is recommended to explore causality and clinical relevance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02389-2.

Systematic reviews and meta-analysis in nutrition research

There exists an ever-increasing number of systematic reviews, with or without meta-analysis, in the field of nutrition. Concomitant with this increase is the increased use of such to guide future research as well as both practice and policy-based decisions. Given this increased production and consumption, a need exists to educate both producers and consumers of systematic reviews, with or without meta-analysis, on how to conduct and evaluate high-quality reviews of this nature in nutrition. The purpose of this paper is to try and address this gap. In the present manuscript, the different types of systematic reviews, with or without meta-analyses, are described as well as the description of the major elements, including methodology and interpretation, with a focus on nutrition. It is hoped that this non-technical information will be helpful to producers, reviewers and consumers of systematic reviews, with or without meta-analysis, in the field of nutrition.

No association between subnormal serum vitamin B12 and anemia in older nursing home patients

PURPOSE

Since evidence of an association between vitamin B12 (B12) deficiency and anemia in older people is limited and inconclusive, we wanted to investigate this association in old, frail nursing home patients.

METHODS

The study includes patients admitted to short-term, post-acute care (n = 765) and residents in long-term care (LTC) (n = 1665), in the municipality of Bergen. Anemia was defined according to the WHO criteria: Hb < 13 g/dL in men and < 12 g/dL in women, and as Hb < 11 g/dL, in both sex (moderate/severe anemia). The presence of anemia was analyzed in patients with subnormal (< 250 pmol/L), normal (250-650 pmol/L) and high (> 650 pmol/L) B12, and the association between anemia and clinical parameters, and including B12, was analyzed using logistic regression models. The use of B12 supplementation was investigated in the LTC patients.

RESULTS

Mean age of the 2430 patients was 86 ± 7 years. WHO-defined anemia was seen in 1023 (42%), and moderate/severe anemia in 384 (16%) of the patients. In multiple logistic regression analyses, we found no statistically significant associations of subnormal B12 with WHO-defined anemia or moderate/severe anemia. Renal insufficiency, iron deficiency and CRP > 10 mg/L were significantly associated with both types of anemia, (p < 0.001). Among the LTC residents, 405 (24%) received B12 supplements, 112 (7%) of them had elevated B12 > 650 pmol/L.

CONCLUSION

In older nursing home patients, no association was observed between subnormal B12 and anemia. Older patients in Western societies with mild/moderate anemia should not be treated with B12 supplements without further investigation.

Vitamin B12 Status and Optimal Range for Hemoglobin Formation in Elite Athletes

Background: Athletes and coaches believe in the ergogenic effect of vitamin B₁₂ (which results from enhanced erythropoiesis) and they often insist on its unjustified supplementation. Therefore, our study aimed to assess the vitamin B₁₂ status in Polish elite athletes and its influence on red blood cell parameters. Methods: In total, 1131 blood samples were collected during six years from 243 track and field athletes divided into strength and endurance groups, as well as according to the declared use of vitamin B₁₂ injections. Results: An average vitamin B₁₂ concentration in all subjects was 739 ± 13 pg/mL, with no cases of deficiency. A weak but significant relationship was found between vitamin B₁₂ and hemoglobin concentrations. A significant increase in hemoglobin appeared from very low vitamin B₁₂ concentration and up to approx. 400 pg/mL, while hemoglobin did not significantly change from 700 pg/mL and onwards. Vitamin B₁₂ injections were used by 34% of athletes, significantly more often by endurance than by strength athletes. In athletes who declared no use of injections, a higher concentration of vitamin B₁₂ was observed in the endurance group. Conclusion: The main finding of the present study is the determination of the range of vitamin B₁₂ concentration which may favor better hemoglobin synthesis in athletes. They should regularly monitor vitamin B₁₂ concentration and maintain the range of 400–700 pg/mL as it may improve red blood cell parameters. We might suggest application of a supplementation if necessary. Special attention is required in athletes with a vitamin B₁₂ concentration below 400 pg/mL.

State of the art review: oral and nasal vitamin B12 therapy in the elderly

The objective of this narrative review was to provide an update on oral and nasal vitamin B12 (cobalamin) therapy in elderly patients. Relevant articles were identified by 'PubMed' and 'Scholar Google' search from January 2010 to July 2018 and through hand search of relevant reference articles. Additional studies were obtained from references of identified studies, the 'Cochrane Library' and the 'ISI Web of Knowledge'. Data retrieved from international meetings were also used, as was information retrieved from commercial sites on the web and data from 'CARE B12' research group. For oral vitamin B12 therapy, four prospective randomized controlled trials, eight prospective studies, one systematic and four reviews fulfilled our inclusion criteria. The studies included mainly or exclusively elderly patients (≥65-year-olds). In all of the studies, the mean age of the patients was at least 70 years except for two. The present review documents that oral vitamin B12 replacement at 1000 μg daily proved adequate to cure vitamin B12 deficiency, with a good safety profile. The efficacy was particularly marked when considering the noticeable improvement in serum vitamin B12 levels and haematological parameters, such as haemoglobin level, mean erythrocyte cell volume and reticulocyte count. The effect of oral cobalamin treatment in patients presenting with severe neurological manifestations has not yet been adequately documented. For nasal vitamin B12, only a few preliminary studies were available. We conclude that oral vitamin B12 is an effective alternative to intramuscular vitamin B12 injections in elderly patients. Oral vitamin B12 treatment avoids the discomfort, inconvenience and cost of monthly injections.