How do we identify and quantify dietary requirements?

2012 ◽  
pp. 7-28
Keyword(s):  
Dietary Requirements

Bioavailability of Vitamin B12

2010 ◽  
Vol 80 (45) ◽  
pp. 330-335 ◽  
Author(s):  
Lindsay Helen Allen
Keyword(s):  
Vitamin B12 ◽  
Vitamin B12 Deficiency ◽  
The Elderly ◽  
Radioactive Isotopes ◽  
Animal Source Foods ◽  
Dietary Requirements ◽  
In Vivo Labeling ◽  
B12 Deficiency ◽  
Vitamin B12 Malabsorption

Vitamin B12 deficiency is common in people of all ages who consume a low intake of animal-source foods, including populations in developing countries. It is also prevalent among the elderly, even in wealthier countries, due to their malabsorption of B12 from food. Several methods have been applied to diagnose vitamin B12 malabsorption, including Schilling’s test, which is now used rarely, but these do not quantify percent bioavailability. Most of the information on B12 bioavailability from foods was collected 40 to 50 years ago, using radioactive isotopes of cobalt to label the corrinoid ring. The data are sparse, and the level of radioactivity required for in vivo labeling of animal tissues can be prohibitive. A newer method under development uses a low dose of radioactivity as 14C-labeled B12, with measurement of the isotope excreted in urine and feces by accelerator mass spectrometry. This test has revealed that the unabsorbed vitamin is degraded in the intestine. The percent bioavailability is inversely proportional to the dose consumed due to saturation of the active absorption process, even within the range of usual intake from foods. This has important implications for the assessment and interpretation of bioavailability values, setting dietary requirements, and interpreting relationships between intake and status of the vitamin.

scholarly journals DIETARY REQUIREMENTS FOR REPRODUCTION

1927 ◽  
Vol 74 (1) ◽  
pp. 71-84
Author(s):  
Barnett Sure ◽  
H.M. Boggs
Keyword(s):  
Dietary Requirements

scholarly journals DIETARY REQUIREMENTS FOR FERTILITY AND LACTATION

1928 ◽  
Vol 76 (3) ◽  
pp. 685-700
Author(s):  
Barnett Sure ◽  
Dorothy J. Walker ◽  
E.H. Stuart
Keyword(s):  
Dietary Requirements

scholarly journals DIETARY REQUIREMENTS FOR FERTILITY AND LACTATION

1928 ◽  
Vol 80 (1) ◽  
pp. 297-307
Author(s):  
Barnett Sure ◽  
Dorothy J. Walker ◽  
E.H. Stuart
Keyword(s):  
Dietary Requirements

scholarly journals Dietary Essential Amino Acid Restriction Promotes Hyperdipsia via Hepatic FGF21

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1469
Author(s):  
Patricia M. Rusu ◽  
Andrea Y. Chan ◽  
Mathias Heikenwalder ◽  
Oliver J. Müller ◽  
Adam J. Rose
Keyword(s):  
Amino Acid ◽  
Growth Factor ◽  
Dietary Protein ◽  
Essential Amino Acid ◽  
De Novo ◽  
Fibroblast Growth Factor 21 ◽  
Fibroblast Growth ◽  
De Novo Biosynthesis ◽  
Dietary Requirements ◽  
Dietary Amino Acid

Prior studies have reported that dietary protein dilution (DPD) or amino acid dilution promotes heightened water intake (i.e., hyperdipsia) however, the exact dietary requirements and the mechanism responsible for this effect are still unknown. Here, we show that dietary amino acid (AA) restriction is sufficient and required to drive hyperdipsia during DPD. Our studies demonstrate that particularly dietary essential AA (EAA) restriction, but not non-EAA, is responsible for the hyperdipsic effect of total dietary AA restriction (DAR). Additionally, by using diets with varying amounts of individual EAA under constant total AA supply, we demonstrate that restriction of threonine (Thr) or tryptophan (Trp) is mandatory and sufficient for the effects of DAR on hyperdipsia and that liver-derived fibroblast growth factor 21 (FGF21) is required for this hyperdipsic effect. Strikingly, artificially introducing Thr de novo biosynthesis in hepatocytes reversed hyperdipsia during DAR. In summary, our results show that the DPD effects on hyperdipsia are induced by the deprivation of Thr and Trp, and in turn, via liver/hepatocyte-derived FGF21.

scholarly journals DIETARY REQUIREMENTS FOR REPRODUCTION

1924 ◽  
Vol 62 (2) ◽  
pp. 371-396
Author(s):  
Barnett Sure
Keyword(s):  
Dietary Requirements

scholarly journals DIETARY REQUIREMENTS FOR REPRODUCTION

1924 ◽  
Vol 58 (3) ◽  
pp. 681-692
Author(s):  
Barnett Sure
Keyword(s):  
Dietary Requirements

scholarly journals Food fortification improves the intake of all fortified nutrients, but fails to meet the estimated dietary requirements for vitamins A and B6, riboflavin and zinc, in lactating South African women

2012 ◽  
Vol 15 (10) ◽  
pp. 1810-1817 ◽  
Author(s):  
Peggy C Papathakis ◽  
Kerry E Pearson
Keyword(s):  
South African ◽  
African Women ◽  
Serum Folate ◽  
Zn Deficiency ◽  
Serum Retinol ◽  
Food Records ◽  
Micronutrient Intake ◽  
Dietary Requirements ◽  
South African Women ◽  
The Impact

AbstractObjectiveTo investigate the impact of fortification by comparing food records and selected biochemical indicators of nutritional status pre- and post-fortification.DesignMean intake from 24 h recalls (n 142) was compared with the Estimated Average Requirement (EAR) to determine the proportion with inadequate intake. In a subsample (n 34), diet and serum retinol, folate, ferritin and Zn were compared pre- and post-fortification for fortified nutrients vitamin A, thiamin, riboflavin, niacin, folic acid, Fe and Zn.SettingSouth Africa.SubjectsBreast-feeding women (ninety-four HIV-infected, forty eight HIV-uninfected) measured at ∼6, 14, 24 weeks, and 9 and 12 months postpartum.ResultsPre-fortification, >80 % of women did not meet the EAR for vitamins A, C, D, thiamin, riboflavin, niacin, B6, B12 and folate and minerals Zn, iodine and Ca. Dietary intake post-fortification increased for all fortified nutrients. In post-fortification food records, >70 % did not meet the EAR for Zn and vitamins A, riboflavin and B6. Serum folate and Zn increased significantly post-fortification (P < 0·001 for both), with no change in ferritin and a reduction in retinol. Post-fortification marginal/deficient folate status was reduced (73·5 % pre v. 3·0 % post; P < 0·001), as was Zn deficiency (26·5 % pre v. 5·9 % post; P < 0·05). Pre- and post-fortification, >93 % were retinol replete. There was no change in Fe deficiency (16·7 % pre v. 19·4 % post; P = 0·728).ConclusionsMicronutrient intake improved with fortification, but >70 % of lactating women did not meet the EAR for Zn, vitamins A, riboflavin and B6. Although 100 % exceeded the EAR for Fe after fortification, Fe status did not improve.

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