1Saw Swee Hock College of Public Well being, Nationwide College of Singapore and Nationwide College Well being System, Singapore, Block MD1, 12 Science Drive 2, Singapore 117549, Singapore
2Office of Scientific Sciences, Duke-NUS Graduate Medical College Singapore, Singapore, 8 Faculty Highway Stage 4, Singapore 169857, Singapore
Summary
1. Introduction
Nutrient deficiency accelerates bone loss in osteoporosis and will increase the propensity to fall, each of that are main causes of hip fracture amongst aged [1,2,3]. Though calcium and vitamin D have been most generally studied because the important vitamins in bone physiology, a number of evaluations have reported that different vitamins can also play necessary physiological roles in selling bone well being [4,5]. The B nutritional vitamins are one group of vitamins which have been investigated for his or her potential roles in bone well being and fracture danger. B nutritional vitamins normally are cofactors for the enzymes which are concerned within the energy-producing metabolic pathways for carbohydrates, fat and proteins. B nutritional vitamins additionally play an necessary function in sustaining capabilities of the nervous system. There are a number of evaluations on B nutritional vitamins and bone well being with a deal with B9 (folate) and B12 (cobalamin), that are cofactors for the enzymes concerned within the remethylation of homocysteine metabolism [6,7,8,9]. Nonetheless, every particular vitamin B (B1, B2, B3, B6, folate, and B12) has different roles in bone physiology as nicely.
Insufficient B vitamin consumption has been reported amongst hip fracture sufferers. The affiliation between numerous B nutritional vitamins (B2, B6, folate, or B12) and a decrease danger of osteoporosis or hip fracture has additionally been demonstrated in a number of observational research. The vast majority of the research had been carried out amongst Caucasian populations, though the findings are inconsistent amongst research or throughout completely different B nutritional vitamins. As well as, homocysteine has been implicated to extend fracture danger, however whether or not these B nutritional vitamins affect bone well being via their hyperlinks with homocysteine metabolism stays to be decided. Nonetheless, opposite to the observational findings, many of the scientific trials carried out thus far don’t seem to help the helpful results of B vitamin supplementation within the prevention of osteoporosis or fracture.
On this overview, we aimed to offer completely different traces of proof from the literature, which embrace in vitro and in vivo experimental research (Desk 1), and proof type observational (Desk 2) and intervention research (Desk 3), to summarize the present findings, and try and shed mild for future analysis instructions in learning the roles of B nutritional vitamins in bone well being.
2. Vitamin B1 (Thiamin)
Vitamin B1, or thiamin, within the lively type, thiamin pyrophosphate (TPP), is a vital cofactor for the important thing enzymes concerned within the metabolism of carbohydrates, lipids and amino acids, and within the synthesis of neurotransmitters [51]. In older people, B1 deficiency can grow to be an issue attributable to diminished urge for food and issue in consuming [52]. The Really helpful Dietary Allowance (RDA) for america (U.S.) is 1.2 mg for grownup males and 1.1 mg for grownup females [53]. Good meals sources of B1 embrace whole-grain meals, wheat germ and yeast extract, and pork meat merchandise [52].
The proof on thiamin and bone well being is scanty. One research amongst orthopedic sufferers reported that thiamin standing was poor amongst sufferers with femoral neck fracture however not amongst those that had been admitted for elective complete hip alternative [54]. Within the Singapore Chinese language Well being Examine, dietary consumption of thiamin was not related to danger of hip fracture in both males or ladies [42]. A latest overview emphasised the key function of thiamin in metabolic perform in cells and the ensuing impairment of neuro-function in thiamin deficiency. As a result of thiamin deficiency can impair power metabolism attributable to mitochondrial dysfunction in focal areas of the mind [55], this in flip can enhance the chance of Alzheimer’s illness and cardiac failure, and due to this fact can enhance the propensity to fall within the aged [55,56], which can result in elevated fracture danger.
3. Vitamin B2 (Riboflavin)
Crucial biologically lively types of vitamin B2 or riboflavin are flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), each of which take part within the oxidation-reduction reactions within the metabolic pathways which are concerned in power manufacturing [57]. As a result of getting older and diminished effectivity in absorption, aged people are liable to have organic deficiency of B2 [58,59]. The U.S. RDA is 1.3 mg for grownup males and 1.1 mg for grownup females [53]. The meals sources that contribute to riboflavin embrace cereals, meat, fatty fish, and dark-green greens. As well as, milk and dairy merchandise fortified with B2 are the largest dietary contributors in Western populations [60].
4. Vitamin B3 (Niacin) – “vitamin b calcium”
Vitamin B3 or niacin is the generic type for nicotinic acid and nicotinamide, each of that are substrates for the lively coenzymes, nicotinamide adenine dinucleotide (NAD) and NAD phosphate (NADP). Each coenzymes are necessary electron acceptors or hydrogen donors for gasoline molecules within the redox reactions. NAD additionally gives substrates for the organic processes concerned in DNA processing, cell differentiation, and mobile calcium mobilization [65]. The biosynthesis of B3 in people is thru the tryptophan-niacin conversion, the place its effectivity will depend on different dietary and hormonal components, equivalent to vitamin B6, B2, and iron, all of that are cofactors for the enzymes within the conversion pathway. However, people additionally get hold of B3 from eating regimen. Wealthy meals sources embrace yeast, meats, cereals, legumes, and seed. An considerable quantity might be present in milk, inexperienced leafy greens, fish, espresso and tea [65]. The U.S. RDA is 16 mg for grownup males and 14 mg for grownup females [53].
5. Vitamin B6 (Pyridoxine)
Vitamin B6 consists of three pyridines: pyridoxine, pyridoxal and pyridoxamine, and their 5’-phosphorylated derivatives. The bioactive type is pyridoxal phosphate (PLP), which is concerned as a cofactor in over 100 enzymatic reactions within the metabolism of glycogen, phospholipids, and amino acids. PLP performs necessary roles in neurotransmitters, within the metabolism of amino acids, homocysteine and cystathione, and within the one-carbon metabolism to have an effect on nucleic acid biosynthesis and functioning of the immune system [70]. Though deficiency of B6 is rare, aged people and alcoholics are in danger attributable to diminished urge for food and malabsorption. The U.S. RDA for adults over 50 years of age is 1.7 mg/day for males and 1.5 mg/day for ladies [53]. Good dietary sources embrace meats, entire grain merchandise, greens, bananas, and nuts.
6. Vitamin B9 (Folate)
Vitamin B9, higher often called folate, performs a central function within the one-carbon metabolism within the nucleotide synthesis, within the metabolism of homocysteine, in addition to within the methylation of DNA, RNA, proteins and phospholipids [78,79]. As a number of B nutritional vitamins are concerned within the metabolism of homocysteine, we’re offering extra element about this pathway right here. Within the methylation pathway, the synthesis of methionine will depend on each folate and B12 for remethylation. Thus, deficiency of both B vitamin would lead to megaloblastic modifications within the bone marrow and different tissues. Alternatively, homocysteine might endure the transsulfuration pathway to generate cysteine, which will depend on B6 as a cofactor for the enzymatic response from cystathionine to cysteine [78]. Deficiency of folate in aged is uncommon; the U.S. RDA for folate is 400 μg/day for each grownup women and men, and the next dosage of 600 μg/day is required for pregnant ladies [53]. Main meals sources of folate embrace citrus fruits, darkish inexperienced leafy greens, and legumes [78].
“vitamin b calcium”