A complete guide to B vitamins. Medically reviewed by Alan Carter, Pharm. Overview Daily values Thiamin Riboflavin Niacin Pantothenic acid Vitamin B-6 Biotin Folate Vitamin B Supplements Summary. How we vet brands and products Medical News Today only shows you brands and products that we stand behind.

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Riboflavin vitamin B Niacin vitamin B Share on Pinterest Some cereals contain added niacin. Pantothenic acid vitamin B Vitamin B Biotin vitamin B Folate vitamin B Share on Pinterest Avocados and some fortified breads are healthful sources of folate. Vitamin B supplements. How we reviewed this article: Sources.

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In mice, vitamin B5 supplementation activates phagocytosis and cytokine production including IL-6 and TNF-α by macrophages and subsequently promotes Th1 and Th17 responses for the clearance of M.

tuberculosis from the lungs Thus, vitamin B5 contributes to host defense by activating immune responses, suggesting that this vitamin has an important role as a natural adjuvant. Vitamin B5 is found in high concentrations as CoA or phosphopantetheine in liver, eggs, chicken, and fermented soybeans.

CoA and phosphopantetheine are converted to free pantothenic acid by endogenous enzymes such as phosphatase and pantetheinase in the small intestine. Free pantothenic acid is absorbed via sodium-dependent multivitamin transporter SMVT expressed on the epithelium of the small intestine and is then released into the blood Finally, free pantothenic acid is converted back to CoA and distributed throughout the body, particularly to the liver and kidney.

Bacterial vitamin B5 is synthesized from 2-dihydropantoate and β-alanine via de novo synthesis pathways Bacterial vitamin B5 exists as free pantothenic acid, which is directly absorbed in the large intestine, converted to CoA, and distributed in the same way as dietary vitamin B5. According to a genomic analysis, Bacteroides fragilis and Prevotella copri Bacteroidetes ; some Ruminococcus spp.

lactaris and R. torques Firmicutes ; Salmonella enterica and Helicobacter pylori Proteobacteria possess a vitamin B5 biosynthesis pathway, indicating that intestinal commensal bacteria can produce vitamin B5. In contrast, most Fusobacterium Fusobacteria and Bifidobacterium spp.

Actinobacteria and some strains of Clostridium difficile, Faecalibacterium spp. Firmicutes lack such a pathway Table 1 , although some of them do express pantothenic acid transporter to utilize vitamin B5 for energy generation 10 , suggesting that these bacteria compete with the host for vitamin B5.

Vitamin B6 exists in several forms, including as pyridoxine, pyridoxal, and pyridoxamine. These forms of vitamin B6 are precursors of the coenzymes pyridoxal phosphate PLP and pyridoxamine phosphate PMP , which are involved in a variety of cellular metabolic processes, including amino acid, lipid, and carbohydrate metabolism Vitamin B6 deficiency is associated with the development of inflammatory diseases such as allergy and rheumatoid arthritis, as well as with neuronal dysfunction 82 — Vitamin B6 deficiency disrupts the Th1—Th2 balance toward an excessive Th2 response, resulting in allergy Moreover, low plasma vitamin B6 levels, together with increased levels of pro-inflammatory cytokines such as TNF-α and IL-6, have been observed in patients with rheumatoid arthritis However, the mechanism underlying the regulation of inflammation by vitamin B6 is currently unknown.

Vitamin B6 contributes to intestinal immune regulation through the metabolism of the lipid mediator sphingosine 1-phosphate S1P.

S1P regulates lymphocyte trafficking into the intestines, especially in the large intestine. Lymphocyte trafficking is dependent on S1P gradient which is created by S1P production and its degradation.

S1P degradation is mediated by S1P lyase that requires vitamin B6 as a cofactor. The administration of vitamin B6 antagonist impairs S1P lyase activity and creates an inappropriate S1P gradient, resulted in impairing lymphocyte migration from lymphoid tissues and reducing the numbers of lymphocytes in the intestines The lymphocytes located between gut epithelial cells are known as intraepithelial cells IELs which are involved in the protection against pathogens Therefore, vitamin B6 is important role for immunosurveillance in the intestines.

Vitamin B6 is abundant in fish, chicken, tofu, sweet potato, and avocado. Dietary vitamin B6 exists as PLP or PMP; it is converted to free vitamin B6 by endogenous enzymes such as pyridoxal phosphatase and is then absorbed by the small intestine.

Although absorption of vitamin B6 through acidic pH-dependent and carrier-mediated transport has been shown, an intestinal pyridoxine transporter is yet to be identified in any mammalian species After the absorption of free vitamin B6, it enters the blood and is converted back to PLP or PMP.

Microbial vitamin B6 is synthesized as PLP from deoxyxylulose 5-phosphate and 4-phosphohydroxy-L-threonine or from glyceraldehydephosphate and d-ribulose 5-phosphate In the large intestine, bacteria-derived PLP is converted to free vitamin B6, which is absorbed by passive transport, transported to the blood, and distributed throughout the body.

Metagenomic analysis has shown that Bacteroides fragilis and Prevotella copri Bacteroidetes , Bifidobacterium longum and, Collinsella aerofaciens Actinobacteria , and Helicobacter pylori Proteobacteria possess a vitamin B6 biosynthesis pathway.

Bacteroidetes and Proteobacteria likely produce vitamin B6 starting from deoxyxylulose 5-phosphate and 4-phosphohydroxy-l-threonine, whereas Actinobacteria likely start from glyceraldehydephosphate and d-ribulose 5-phosphate. In contrast, most Firmicutes genera Veillonella, Ruminococcus, Faecalibacterium , and Lactobacillus spp.

bartlettii, C. leptum, C. methylpentosum , and C. sporogenes and Lactobacillus spp. brevis and L. ruminis lack a vitamin B6 biosynthesis pathway 10 Table 1. Vitamin B7 biotin is a cofactor for several carboxylases that are essential for glucose, amino acid, and fatty acid metabolism For example, vitamin B7 is an essential cofactor for acetyl-CoA carboxylase and fatty acid synthase, which are enzymes involved in fatty acid biosynthesis 90 , Thus, vitamin B7 likely influences immunometabolism.

Vitamin B7 suppresses gene expression by binding to biotinylating histones; these genes include that encoding NF-κB, which is a major signaling molecule for the production of several pro-inflammatory cytokines e.

Nuclear transcription of NF-κB is activated in response to vitamin B7 deficiency 94 , suggesting that biotinylation of histones suppresses the expression of genes encoding pro-inflammatory cytokines in NF-κB signaling Figure 3. Therefore, vitamin B7 has anti-inflammatory effects by inhibiting NF-κB activation, and dietary vitamin B7 deficiency causes inflammatory responses via enhanced secretion of pro-inflammatory cytokines 95 , Vitamin B7 is abundant in foods such as nuts, beans, and oilseed.

However, raw egg-white contains a large amount of avidin, which binds strongly to vitamin B7 and prevents its absorption in the gut Therefore, vitamin B7 deficiency can be caused not only by insufficient vitamin B7 intake, but also by excessive intake of raw egg-white.

Dietary biotin exists as a free protein-bound form or as biocytin In the small intestine, biotinidase releases free biotin from the bound protein and the free biotin is absorbed via the biotin transporter SMVT Vitamin B7 is also produced by intestinal bacteria as free biotin synthesized from malonyl CoA or pimelate via pimeloyl-CoA 99 , Bacterial free biotin is absorbed by SMVT expressed in the colon 23 , Metagenomic analysis has shown that Bacteroides fragilis and Prevotella copri Bacteroidetes ; Fusobacterium varium Fusobacteria and Campylobacter coli Proteobacteria possess a vitamin B7 biosynthesis pathway In contrast, Prevotella spp.

Bacteroidetes , Bifidobacterium spp. Actinobacteria , and Clostridium, Ruminococcus, Faecalibacterium , and Lactobacillus spp. Firmicutes lack such a pathway Table 1 ; however, they do express free biotin transporter 10 , , suggesting that these bacteria also utilize dietary and bacterial vitamin B7 and therefore may compete with the host.

Thus, free biotin may influence the composition of the gut microbiota, because biotin is necessary for the growth and survival of the microbiota. Indeed, biotin deficiency leads to gut dysbiosis and the overgrowth of Lactobacillus murinus , leading to the development of alopecia Furthermore, vitamin B7 production appears to proceed in a cooperative manner among different intestinal bacteria; Bifidobacterium longum in the intestine produces pimelate, which is a precursor of vitamin B7 that enhances vitamin B7 production by other intestinal bacteria Vitamin B9 folate , in its active form as tetrahydrofolate, is a cofactor in several metabolic reactions, including DNA and amino acid synthesis.

Owing to the high requirement of vitamin B9 by red blood cells, vitamin B9 deficiency leads to megaloblastic anemia Moreover, vitamin B9 contributes to the maintenance of immunologic homeostasis. Regulatory T cells Treg express high levels of vitamin B9 receptor folate receptor 4 [FR4].

Administration of anti-FR4 antibody results in specific reduction in the Treg cell population , suggesting that the vitamin B9—FR4 axis is required for Treg cell maintenance. In vitro culture of Treg cells under vitamin B9-reduced conditions leads to impaired cell survival, with decreased expression of anti-apoptotic Bcl2 molecules, although naïve T cells retain the ability to differentiate into Treg cells; this suggests that vitamin B9 is a survival factor for Treg cells Consistent with these findings, deficiency of dietary vitamin B9 results in reduction of the Treg cell population in the small intestine , Since Treg cells play an important role in the prevention of excessive immune responses , mice fed a vitamin B9-deficient diet exhibit increased susceptibility to intestinal inflammation Foods such as beef liver, green leafy vegetables, and asparagus contain high levels of vitamin B9.

Vitamin B9 exists as both mono- and polyglutamate folate species in the diet Folate polyglutamate is deconjugated to the monoglutamate form and then absorbed in the small intestine via folate transporters such as proton-coupled folate transporter PCFT 11 , In the intestinal epithelium, folate monoglutamate is converted to tetrahydrofolate THF , an active form and cofactor, before being transported to the blood Intestinal bacteria synthesize vitamin B9 as THF from GTP, erythrose 4-phosphate, and phosphoenolpyruvate 38 , Bacterial THF is directly absorbed in the colon via PCFT and distributed through the body by the blood Metagenomic analysis has shown that Bacteroides fragilis and Prevotella copri Bacteroidetes ; Clostridium difficile, Lactobacillus plantarum, L.

reuteri, L. delbrueckii ssp. bulgaricus , and Streptococcus thermophilus Firmicutes , some species in Bifidobacterium spp Actinobacteria ; Fusobacterium varium Fusobacteria and Salmonella enterica Proteobacteria possess a folate biosynthesis pathway Table 1 10 , This suggests that almost all species in all phyla produce folate.

Indeed, dietary supplementation with Bifidobacterium probiotic strains B. adolescentis and B. pseudocatenulatum enhances folate production in the large intestine of folate-deficient rats and folate-free culture medium 38 , 41 , Furthermore, Lactobacillus plantarum, L.

bulgaricus , and L. reuteri enhance folate production in bacterial culture supernatant lacking the components needed for folate synthesis 38 , 39 , In commensal bacteria, a vitamin B9 metabolite, 6-formylpterin 6-FP , is produced by photodegradation of folic acid Like the vitamin B2 metabolite 6-hydroxymethyld-ribityllumazine, 6-FP binds to MR1, but unlike 6-hydroxymethyld-ribityllumazine it cannot activate MAIT cells 62 , An analog of 6-FP, acetylFP, is an antagonist of MR1, which inhibits MAIT cell activation As mentioned in the section on vitamin B2, 6-hydroxymethyld-ribityllumazine activates MAIT cells, which provide defense against pathogens, so vitamin B9 metabolites may suppress excess MAIT cell responses and prevent excessive allergic and inflammatory responses Figure 2.

The quantitative balance between dietary vitamin B2 and B9 and the composition of the microbiota and its ability to metabolize these vitamins may be keys to understanding MAIT-cell-mediated homeostasis in the intestine.

Vitamin B12 cobalamin is a cobalt-containing vitamin that, in its active forms of methylcobalamin and adenosylcobalamin, catalyzes methionine synthesis Together with vitamin B6 and B9, vitamin B12 plays important roles in red blood cell formation and nucleic acid synthesis, especially in neurons.

Therefore, vitamin B12 deficiency causes megaloblastic anemia and nervous system symptoms such as numbness of the hands and feet Beef liver, bivalves, fish, chicken, and eggs contain high levels of vitamin B Dietary vitamin B12 exists in complex with dietary protein and is decomposed to free vitamin B12 by pepsin in the stomach.

Free vitamin B12 is absorbed by the epithelial cells of the small intestine via intrinsic factor IF , a gastric glycoprotein. Inside the epithelial cells, IF-vitamin B12 complex is decomposed to free vitamin B12 by lysosome and then released into the blood, where it is converted to the active form and distributed throughout the body , Bacterial vitamin B12 is synthesized from precorrin-2 to produce adenosylcobalamin 10 , which is absorbed directly by the large intestine and distributed throughout the body; the mechanism underlying this absorption is currently unclear.

Metagenomic analysis has predicted that Bacteroides fragilis and Prevotella copri Bacteroidetes ; Clostridium difficile, Faecalibacterium prausnitzii and Ruminococcus lactaris Firmicutes ; Bifidobacterium animalis, B.

infantis , and B. longum Actinobacteria ; Fusobacterium varium Fusobacteria possess a vitamin B12 biosynthesis pathway Table 1 10 , 32 , 42 , 43 , Indeed, Lactobacillus plantarum and L.

coryniformis isolated from fermented food produce vitamin B12 33 , and Bifidobacterium animalis synthesizes vitamin B12 during milk fermentation B-vitamin-mediated immunological regulation is specific to different immune cells and immune responses: that is, different B vitamins are required for different immune responses Figure 4.

It was once thought that B vitamins were obtained only from the diet; however, we know now that this is not the case and that the intestinal microbiota is also an important source of vitamins.

Within the intestinal microbiota, not all bacteria produce B vitamins and some bacteria utilize dietary B vitamins or B vitamins produced by other intestinal bacteria for their own needs; therefore, there may be competition between the host and the intestinal microbiota for B vitamins Figure 4.

Research in this field is complicated, because not only does the composition of the intestinal microbiota vary among individuals, but also the composition of the diet can alter both the composition and function of the intestinal microbiota. Therefore, vitamin-mediated immunological maintenance also varies among individuals.

Further examinations in this field are needed, and the new information uncovered will help to develop a new era of precision health and nutrition.

Figure 4. Schematic representation of B-vitamin-mediated interaction between commensal bacteria and host immunity. KY and KH wrote the draft of review article which was corrected by JK. KY, KH, and KS drew figures and JK performed correction. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

This review article contains results obtained from our studies that were supported at least in part by grants from the Japan Agency for Medical Research and Development [AMED; 17fkh JK , 17eks JK , 17fkh JK , 17ekh JK , 17akh JK , 17gms JK , and 19ekh JK ]; Cross-ministerial Strategic Innovation Promotion Program; the Ministry of Health, Labor, and Welfare of Japan; the Science and Technology Research Promotion Program for Agriculture, Forestry, Fisheries, and Food Industry; the Ministry of Education, Culture, Sports, Science, and Technology of Japan; the Japan Society for the Promotion of Science [JSPS, JP16H JK , JP15H JK , JP17H JK , JP JK , JP JK , JP18K KH , and JP18J KH ]; the ONO Medical Research Foundation JK ; the Canon Foundation JK ; the Terumo Foundation for the Life Sciences and Arts; and the Nippon Ham Foundation for the Future of Food.

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Proc Natl Acad Sci USA. Jurgenson CT, Begley TP, Ealick SE. other methylation reactions in the central nervous system [3].

The B vitamins are B1, B2, B6, B12, folic acid, pantothenic acid, niacin and biotin [6]. In the case of vitamin B1 or thiamine, this is the most active form of thiamine pyrophosphate, and can be found in the diet in whole grains, wheat germ, yeast, soybean meal and wheat and pork [6].

Vegetables, fruits, eggs, chicken, mutton and ox are intermediate sources, whereas milk contains relatively low amounts of thiamine [7]. This has an important role in the well-being [7] and its storage is very little and can occur preferentially in the skeletal muscle, being half of its value absorbed, followed by the liver, heart, kidneys and brain and this storage increases little if large amounts were ingested [6,7].

The role of this vitamin is essential to help cells convert carbohydrates into energy and is necessary for the proper functioning of nerve cells and the brain [7].

Vitamin B1 is the most sensitive to temperature, and losses may occur during the thermal processing of foods and the recommended daily dose varies for men and women, due to differences in size and energy consumption [7].

Vitamin B2 acts as a redox cofactor in energy-generating metabolism, being essential for the formation of erythrocytes, neo-glycogenesis and regulation of thyroid enzymes, and helps cells convert carbohydrates into energy, being essential for the growth of cells, production of red blood cells and the health of the eyes and skin [6].

This vitamin loses its characteristics when exposed to light [6]. Riboflavin deficiencies are rare, since they are related to the metabolism of other vitamins, and a deficiency occurs when deficiency occurs [6].

The distribution of riboflavin in foods is wide, but its concentration is low. Among the food sources, milk and its derivatives, meat and viscera such as liver and kidneys , green leafy vegetables such as cabbage, broccoli, cabbage and watercress , eggs and peas can be highlighted [8].

In the case of the vitamin of vitamin B6 we can highlight the pyridoxine that represents the most stable form of this vitamin [9]. This in the body is converted to pyridoxal phosphate, which acts as a coenzyme of about 60 enzymes, most related to the metabolism of proteins and amino acids.

This vitamin plays an important role in the synthesis of neurotransmitters such as noradrenaline, dopamine, serotonin and histamine. It also participates in amino acid degradation reactions, in which one of the end products is acetylcoenzyme A, necessary to produce energy and the synthesis of proteins, lipids and acetylcholine [9].

The sources of this vitamin are liver, cereal meal, yeast, crude cane molasses and wheat germ [9]. Vitamin B12 or cyancobalamin is only found naturally in foods of animal origin, such as in tissues, eggs and milk [10,11]. Vitamin B12 is an essential component of the proliferation and cellular differentiation of haematopoiesis and neurological functions, being essential for the synthesis of nucleic acids, erythrocytes and myelination [10,11].

Individuals consume about 2. Vitamin B9 or folic acid, participates in the metabolism of amino acids and the synthesis of nucleic acids, being essential for the formation of blood cells and are important for biochemical processes, such as DNA synthesis and repair [10,11].

The best sources of folic acid are viscera, beans and green leafy vegetables such as spinach, asparagus and broccoli. Other examples of foods are avocado, pumpkin, potato, beef, pork, carrot, cabbage, liver, orange, milk, apple, corn, egg, cheese.

Go to Mini Review Abstract Introduction Discussion Conclusion References Discussion Vitamins mainly from B complex have potential ergogenic effects by adjusting the energetic metabolism of physical activities and improving exercise performance when supplemented [14,15].

This supplementation can be diffused in recreational and competition athletes, and these vitamins are particularly important in the practice of physical exercise because they are involved in the regulation of energy metabolism, modulating the synthesis and degradation of carbohydrates, fats and proteins [16].

In the case of folic acid, it acts as an essential cofactor in methylation reactions, including in the formation of vitamin B12, among other important reactions [16]. Both B complex vitamins are involved as coenzymes of numerous regulatory enzymes [4], assisting cell division, nutrients eeses that are essential for growth, synthesis of new cells such as red blood cells, and for the repair of damaged cells and tissues [16].

In the degradation of amino acids such as valine, isoleucine, methionine and threonine and fatty acids, these amino acids are converted to propionyl- CoA and the fatty acids are oxidized to acetyl-CoA and propionyl- CoA.

Acetyl-CoA goes directly into the tricarboxylic acid cycle [16]. Propionyl-CoA is carboxylated in methyl malonyl-CoA and finally converted to succinyl-CoA by methyl malonyl-CoA mutase [14]. This enzyme requires vitamin B12 as a cofactor [16]. Thus, the state and needs for folic acid and vitamin B12 can be altered by energy production and reconstruction and repair of muscle tissue induced by physical activity [16].

The International Sports Nutrition Society recommends that energy requirements be scaled to activity level, body mass and mode of exercise [17] to ensure that specific individual needs are suppressed [17].

Achieving micronutrient sufficiency is an important concern for all athletes, so poorly planned diets can predispose individuals to micronutrient deficiency, regardless of predilection, which may have implications for athlete health and performance [17].

Thiamine, important in energy metabolism [18], is a coenzyme of pyruvate dehydrogenase that stimulates the conversion of pyruvate to acetyl-CoA and plays an important role in the metabolism of carbohydrates [14].

Decreasing thiamine concentration in cells provides degradation of enzyme activation, decreases ATP biosynthesis, and causes fatigue [14]. Such a low level of thiamine in the body can degrade exercise performance [14]. This vitamin, such as thiamine pyrophosphate, plays a key role in the metabolism of carbohydrates and proteins [14].

Nearly half of the thiamine in the body is stored in the muscles and thiamine is required for the normal functioning of skeletal and cardiac musculature, so thiamine may be a potentially limiting nutrient in physical activity [14].