Thiamin Metabolism in Man

Ariaey-Nejad, M. R.; Balaghi, Mesbaheddin; Baker, Eugene M.; Sauberlich, Howerde E.

doi:10.1093/ajcn/23.6.764

Cited by 61 publications

(32 citation statements)

References 16 publications

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“…A similar phenomenon was reported by Stevenson (7) and Consolazio et al (8), and they considered that repletion of body stores of vitamin B 1 was fairly rapid. Total thiamin content in adult human has been estimated to be approximately 30 mg (24). Vitamin B1 requirement is closely related to energy consumption, particularly that derived from carbohydrate.…”

Section: Discussionmentioning

confidence: 99%

Effect of Fasting on the Urinary Excretion of Water-Soluble Vitamins in Humans and Rats

Fukuwatari

Yoshida

Takahashi

et al. 2010

J Nutr Sci Vitaminol

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Summary Recent studies showed that the urinary excretion of the water-soluble vitamins can be useful as a nutritional index. To determine how fasting affects urinary excretion of water-soluble vitamins, a human study and an animal experiment were conducted. In the human study, the 24-h urinary excretion of water-soluble vitamins in 12 healthy Japanese adults fasting for a day was measured. One-day fasting drastically decreased urinary thiamin content to 30%, and increased urinary riboflavin content by 3-fold. Other water-soluble vitamin contents did not show significant change by fasting. To further investigate the alterations of water-soluble vitamin status by starvation, rats were starved for 3 d, and water-soluble vitamin contents in the liver, blood and urine were measured during starvation. Urinary excretion of thiamin, riboflavin, vitamin B 6 metabolite 4-pyridoxic acid, nicotinamide metabolites and folate decreased during starvation, but that of vitamin B 12 , pantothenic acid and biotin did not. As for blood vitamin levels, only blood vitamin B 1 , plasma PLP and plasma folate levels decreased with starvation. All water-soluble vitamin contents in the liver decreased during starvation, whereas vitamin concentrations in the liver did not decrease. Starvation decreased only concentrations of vitamin B 12 and folate in the skeletal muscle. These results suggest that water-soluble vitamins were released from the liver, and supplied to the peripheral tissues to maintain vitamin nutrition. Our human study also suggested that the effect of fasting should be taken into consideration for subjects showing low urinary thiamin and high urinary riboflavin. Key Words human, rats, fasting, urine, biomarker A biological assay technique to assess water-soluble vitamins in healthy human subjects was reported by Melnick et al . in 1945 ( 1 ), and this technique became popular in the 1960 s and 1970 s. Urinary excretion of thiamin, riboflavin and niacin metabolites has been used for setting Dietary Reference Intakes (DRIs) of vitamin B 1 , vitamin B 2 and niacin in the USA and Japan ( 2 , 3 ). Recent validation studies have developed the urinary compounds as nutritional markers to estimate nutrient intakes. We have recently reported that each of the water-soluble vitamins or its metabolite levels in the 24-h urine are strongly correlated with its intake when young women consume the standard Japanese diet with several amounts of water-soluble vitamin ( 4 ). Thirtyday mean thiamin levels in 24-h urine are also highly correlated with mean intake of vitamin B 1 ( 5 ). These findings show that urinary excretion of water-soluble vitamins reflects their intakes when subjects constantly take certain amounts of water-soluble vitamins. It is well known that pharmacological doses of water-soluble vitamins acutely increase their excretion to urine, and that a chronic water-soluble vitamin restricted diet reduces its levels in urine and blood ( 6 ). Effects of acute deprivation of water-soluble vitamins on their urinary excretion have a...

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Section: Discussionmentioning

confidence: 99%

Effect of Fasting on the Urinary Excretion of Water-Soluble Vitamins in Humans and Rats

Fukuwatari

Yoshida

Takahashi

et al. 2010

J Nutr Sci Vitaminol

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“…More generally, the damage reactions undergone by all B vitamins account for their dietary requirements; if vitamins were not continuously damaged, they would last forever and not need to be constantly resupplied. In this context, it is noteworthy that the whole-body half-life of thiamin (and its phosphates) in humans is one to two orders of magnitude shorter than those of other B vitamins for which estimates are available, as follows: thiamin, 9.5 to 18.5 d (Ariaey-Nejad et al, 1970); folates, 60 to 150 d (Gregory and Quinlivan, 2002); vitamin B 6 , ;500 d (Coburn, 1990); vitamin B 12 (absent from plants), 480 to 1284 d (Hall, 1964). …”

Section: Chemical and Metabolic Lability: Why Bad Things Happen To Gomentioning

confidence: 99%

Does Abiotic Stress Cause Functional B Vitamin Deficiency in Plants?

et al. 2016

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B vitamins are the precursors of essential metabolic cofactors but are prone to destruction under stress conditions. It is therefore a priori reasonable that stressed plants suffer B vitamin deficiencies and that certain stress symptoms are metabolic knock-on effects of these deficiencies. Given the logic of these arguments, and the existence of data to support them, it is a shock to realize that the roles of B vitamins in plant abiotic stress have had minimal attention in the literature (100-fold less than hormones) and continue to be overlooked. In this article, we therefore aim to explain the connections among B vitamins, enzyme cofactors, and stress conditions in plants. We first outline the chemistry and biochemistry of B vitamins and explore the concept of vitamin deficiency with the help of information from mammals. We then summarize classical and recent evidence for stress-induced vitamin deficiencies and for plant responses that counter these deficiencies. Lastly, we consider potential implications for agriculture.

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“…This is not a concern, but rather it might be expected that patients have continued benefit during the washout period from the thiamine supplementa-tion in the preceding 3 months. The half-life of thiamine in plasma is relatively short (2 days) [3], whereas the biological half-life of thiamine is much greater (9-18 days) [4]. The plasma concentration and urinary excretion of thiamine of patients in the thiamine treatment arm of the study returned to baseline levels after the 2 month washout period.…”

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confidence: 97%

Thiamine in diabetic nephropathy: a novel treatment modality? Reply to Alkhalaf A, Kleefstra N, Groenier KH et al. [letter]

et al. 2009

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Abbreviations ACEIAngiotensin-converting enzyme inhibitor ARB Angiotensin receptor blocker RAAS Renin-angiotensin-aldosterone system sVCAM-1 Soluble vascular cell adhesion molecule-1 TPP Thiamine pyrophosphate UAE Urinary albumin excretionTo the Editor: We thank Alkhalaf and co-authors for their comment on our recent paper in Diabetologia [1]. We are grateful for their interest in our work and the recognition of its potential importance in stimulating further research, which may lead to a significant improvement in the treatment of diabetic nephropathy. They have made several comments on issues that could not be dealt with in our short communication [2]. We now address these comments. The urinary albumin excretion (UAE) data in Table 1 of our paper are the median (minimum-maximum) values of the 24 h UAE values for the treatment groups at the study times indicated. The data illustrated in Fig. 1a are the median values of data distributions of 24 h UAE change from baseline deduced for each patient. These data sets are not the same: one is absolute UAE values (distributions summarised in Table 1) and the other is of changes in UAE from baseline for each patient (medians of changes shown in Fig. 1a). This, and the non-parametric distribution of the data sets, accounts for the different values for the difference between median UAE after 3 months of treatment and at baseline (−13.6 mg/24 h) that can be deduced from Table 1 and the median of 24 h UAE changes from baseline (−17.7 mg/24 h) shown in Fig. 1a for the thiamine treatment group. Computing a data distribution of analyte change from baseline is a strategy often employed where there is large dispersion of baseline data, and the response to therapy (rather than change in absolute value) is of greatest interest. Change in UAE was the primary endpoint of our study.There was a trend for UAE data during the posttreatment washout period to show a continuing decrease beyond that achieved in the treatment period. We stated that the decrease in UAE in the post-treatment period was 'maintained', as the trend for further decrease was not statistically significant. This is not a concern, but rather it might be expected that patients have continued benefit during the washout period from the thiamine supplementaDiabetologia

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Thiamin Metabolism in Man

Cited by 61 publications

References 16 publications

Effect of Fasting on the Urinary Excretion of Water-Soluble Vitamins in Humans and Rats

Effect of Fasting on the Urinary Excretion of Water-Soluble Vitamins in Humans and Rats

Does Abiotic Stress Cause Functional B Vitamin Deficiency in Plants?

Thiamine in diabetic nephropathy: a novel treatment modality? Reply to Alkhalaf A, Kleefstra N, Groenier KH et al. [letter]

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