Vitamin B12 among Vegetarians: Status, Assessment and Supplementation

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

Cobalamin is an essential molecule for humans. It acts as a cofactor in one-carbon transfers through methylation and molecular rearrangement. These functions take place in fatty acid, amino acid and nucleic acid metabolic pathways. The deficiency of vitamin B12 is clinically manifested in the blood and nervous system where the cobalamin plays a key role in cell replication and in fatty acid metabolism. Hypovitaminosis arises from inadequate absorption, from genetic defects that alter transport through the body, or from inadequate intake as a result of diet. With the growing adoption of vegetarian eating styles in Western countries, there is growing focus on whether diets that exclude animal foods are adequate. Since food availability in these countries is not a problem, and therefore plant foods are sufficiently adequate, the most delicate issue remains the contribution of cobalamin, which is poorly represented in plants. In this review, we will discuss the status of vitamin B12 among vegetarians, the diagnostic markers for the detection of cobalamin deficiency and appropriate sources for sufficient intake, through the description of the features and functions of vitamin B12 and its absorption mechanism.

Related collections

Most cited references 195

Record: found
Abstract: found
Article: not found

Homocysteine and risk of ischemic heart disease and stroke: a meta-analysis.

George Smith, Friedrich Luft, Ellen Hoogeveen (2002)

It has been suggested that total blood homocysteine concentrations are associated with the risk of ischemic heart disease (IHD) and stroke. To assess the relationship of homocysteine concentrations with vascular disease risk. MEDLINE was searched for articles published from January 1966 to January 1999. Relevant studies were identified by systematic searches of the literature for all reported observational studies of associations between IHD or stroke risk and homocysteine concentrations. Additional studies were identified by a hand search of references of original articles or review articles and by personal communication with relevant investigators. Studies were included if they had data available by January 1999 on total blood homocysteine concentrations, sex, and age at event. Studies were excluded if they measured only blood concentrations of free homocysteine or of homocysteine after a methionine-loading test or if relevant clinical data were unavailable or incomplete. Data from 30 prospective or retrospective studies involving a total of 5073 IHD events and 1113 stroke events were included in a meta-analysis of individual participant data, with allowance made for differences between studies, for confounding by known cardiovascular risk factors, and for regression dilution bias. Combined odds ratios (ORs) for the association of IHD and stroke with blood homocysteine concentrations were obtained by using conditional logistic regression. Stronger associations were observed in retrospective studies of homocysteine measured in blood collected after the onset of disease than in prospective studies among individuals who had no history of cardiovascular disease when blood was collected. After adjustment for known cardiovascular risk factors and regression dilution bias in the prospective studies, a 25% lower usual (corrected for regression dilution bias) homocysteine level (about 3 micromol/L [0.41 mg/L]) was associated with an 11% (OR, 0.89; 95% confidence interval [CI], 0.83-0.96) lower IHD risk and 19% (OR, 0.81; 95% CI, 0.69-0.95) lower stroke risk. This meta-analysis of observational studies suggests that elevated homocysteine is at most a modest independent predictor of IHD and stroke risk in healthy populations. Studies of the impact on disease risk of genetic variants that affect blood homocysteine concentrations will help determine whether homocysteine is causally related to vascular disease, as may large randomized trials of the effects on IHD and stroke of vitamin supplementation to lower blood homocysteine concentrations.

0 comments Cited 297 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Relation Between Red Blood Cell Distribution Width and Cardiovascular Event Rate in People With Coronary Disease.

Marcello Tonelli, Frank Sacks, Malcolm Arnold … (2008)

BACKGROUND: Higher levels of red blood cell distribution width (RDW) may be associated with adverse outcomes in patients with heart failure. We examined the association between RDW and the risk of all-cause mortality and adverse cardiovascular outcomes in a population of people with coronary disease who were free of heart failure at baseline. METHODS AND RESULTS: We performed a post hoc analysis of data from the Cholesterol and Recurrent Events study. Baseline RDW was measured in 4111 participants who were randomized to receive pravastatin 40 mg daily or placebo and followed for a median of 59.7 months. We used Cox proportional hazards models to examine the association between RDW and adverse clinical outcomes. During nearly 60 months of follow-up, 376 participants died. A significant association was noted between baseline RDW level and the adjusted risk of all-cause mortality (hazard ratio per percent increase in RDW, 1.14; 95% confidence interval, 1.05 to 1.24). After categorization based on quartile of baseline RDW and further adjustment for hematocrit and other cardiovascular risk factors, a graded independent relation between RDW and death was observed (P for trend=0.001). For instance, participants with RDW in the highest quartile had an adjusted hazard ratio for death of 1.78 (95% confidence interval, 1.28 to 2.47) compared with those in the lowest quartile. Higher levels of RDW were also associated with increased risk of coronary death/nonfatal myocardial infarction, new symptomatic heart failure, and stroke. CONCLUSIONS: We found a graded independent relation between higher levels of RDW and the risk of death and cardiovascular events in people with prior myocardial infarction but no symptomatic heart failure at baseline.

0 comments Cited 260 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Neuropsychiatric disorders caused by cobalamin deficiency in the absence of anemia or macrocytosis.

John Lindenbaum, Edward B. Healton, David G Savage … (1988)

Among 141 consecutive patients with neuro-psychiatric abnormalities due to cobalamin deficiency, we found that 40 (28 percent) had no anemia or macrocytosis. The hematocrit was normal in 34, the mean cell volume was normal in 25, and both tests were normal in 19. Characteristic features in such patients included paresthesia, sensory loss, ataxia, dementia, and psychiatric disorders; longstanding neurologic symptoms without anemia; normal white-cell and platelet counts and serum bilirubin and lactate dehydrogenase levels; and markedly elevated serum concentrations of methylmalonic acid and total homocysteine. Serum cobalamin levels were above 150 pmol per liter (200 pg per milliliter) in 2 patients, between 75 and 150 pmol per liter (100 and 200 pg per milliliter) in 16, and below 75 pmol per liter (100 pg per milliliter) in only 22. Except for one patient who died during the first week of treatment, every patient in this group benefited from cobalamin therapy. Responses included improvement in neuropsychiatric abnormalities (39 of 39), improvement (often within the normal range) in one or more hematologic findings (36 of 39), and a decrease of more than 50 percent in levels of serum methylmalonic acid, total homocysteine, or both (31 of 31). We conclude that neuropsychiatric disorders due to cobalamin deficiency occur commonly in the absence of anemia or an elevated mean cell volume and that measurements of serum methylmalonic acid and total homocysteine both before and after treatment are useful in the diagnosis of these patients.

0 comments Cited 174 times – based on 0 reviews      Review now

Bookmark

All references

Author and article information

Journal

Journal ID (nlm-ta): Nutrients

Journal ID (iso-abbrev): Nutrients

Journal ID (publisher-id): nutrients

Title: Nutrients

Publisher: MDPI

ISSN (Electronic): 2072-6643

Publication date (Electronic): 29 November 2016

Publication date Collection: December 2016

Volume: 8

Issue: 12

Electronic Location Identifier: 767

Affiliations

[1 ]Vico Sant’andrea 5, Ritiro, Messina 98152, Italy; gianlucarizzo@ 123456email.it

[2 ]Unit of Gynecology and Obstetrics, Department of Human Pathology in Adulthood and Childhood, “G. Barresi”, University of Messina, Via Consolare Valeria 1, Messina 98125, Italy; vitalesalvatore@ 123456hotmail.com

[3 ]Department of General Surgery and Medical Surgical Specialties, University of Catania, Via S. Sofia 78, Catania 95124, Italy; agni.rap@ 123456live.it (A.M.C.R.); valentigaetano@ 123456gmail.com (G.V.); fabrizio.sapia@ 123456libero.it (F.S.); peppe_sarpietro@ 123456hotmail.com (G.S.); micolziga@ 123456gmail.com (M.Z.)

[4 ]Department of Gastroenterology and Digestive Endoscopy Maddalena Raimondi San Cataldo, Via Forlanini 5, San Cataldo, Caltanissetta 93017, Italy; giolaferrera@ 123456libero.it

[5 ]Unit of Diabetology and Endocrino-Metabolic Diseases, Hospital for Emergency Cannizzaro, Via Messina 829, Catania 95126, Italy; buscemamassimo@ 123456gmail.com (M.B.); paolarossetti@ 123456alice.it (P.R.); ang.nigro@ 123456gmail.com (A.N.); vince80@ 123456alice.it (V.M.)

Author notes

[* ]Correspondence: antlagana@ 123456unime.it ; Tel.: +39-090-221-2183; Fax: +39-090-293-7083

Article

Publisher ID: nutrients-08-00767

DOI: 10.3390/nu8120767

PMC ID: 5188422

PubMed ID: 27916823

SO-VID: ce0531a5-fcdf-436c-b00f-8454cf5bf7d9

License:

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license ( http://creativecommons.org/licenses/by/4.0/).

History

Date received : 03 September 2016

Date accepted : 23 November 2016

Comments

Comment on this article

scite_

Smart Citations

Citing PublicationsSupportingMentioningContrasting

View Citations

See how this article has been cited at scite.ai

scite shows how a scientific paper has been cited by providing the context of the citation, a classification describing whether it supports, mentions, or contrasts the cited claim, and a label indicating in which section the citation was made.

Cited by 112

See all cited by

Most referenced authors 1,995

See all reference authors

Vitamin B12 among Vegetarians: Status, Assessment and Supplementation

Read this article at

Abstract

Related collections

Karger: Nutrition and Dietetics

Most cited references 195

Homocysteine and risk of ischemic heart disease and stroke: a meta-analysis.

Relation Between Red Blood Cell Distribution Width and Cardiovascular Event Rate in People With Coronary Disease.

Neuropsychiatric disorders caused by cobalamin deficiency in the absence of anemia or macrocytosis.

Author and article information

Journal

Affiliations

Author notes

Article

History

Categories

Comments

Comment on this article

Similar content 937

Cited by 112

Most referenced authors 1,995