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Fulltext Diet and cancer

Med J Malaysia, 1988 Dec;43(4):348-9.
PMID: 2853823
Matched MeSH terms: Ascorbic Acid/adverse effects
Fulltext Crystal deposits in cornea from the use of vitamin C eye drops

Choong YY, Arumugam G

Med J Malaysia, 1999 Dec;54(4):526-7.
PMID: 11072476

There are a number of differential diagnoses for crystal deposits in the cornea. With the presence of a corneal epithelial defect, the differential diagnosis can be narrowed down to either infective causes or deposits from topical medications. This report describes a case of crystal deposits in the cornea from the use of Vitamin C eye drops.

Matched MeSH terms: Ascorbic Acid/adverse effects*
Vitamin C and Bone Health: Evidence from Cell, Animal and Human Studies

Chin KY, Ima-Nirwana S

Curr Drug Targets, 2018;19(5):439-450.
PMID: 26343111 DOI: 10.2174/1389450116666150907100838

BACKGROUND: Vitamin C, traditionally associated with scurvy, is an important nutrient for maintaining bone health. It is essential in the production of collagen in bone matrix. It also scavenges free radicals detrimental to bone health.
OBJECTIVE: This review aims to assess the current evidence of the bone-sparing effects of vitamin C derived from cell, animal and human studies.
RESULTS: Cell studies showed that vitamin C was able to induce osteoblast and osteoclast formation. However, high-dose vitamin C might increase oxidative stress and subsequently lead to cell death. Vitamin C-deficient animals showed impaired bone health due to increased osteoclast formation and decreased bone formation. Vitamin C supplementation was able to prevent bone loss in several animal models of bone loss. Human studies generally showed a positive relationship between vitamin C and bone health, indicated by bone mineral density, fracture probability and bone turnover markers. Some studies suggested that the relationship between vitamin C and bone health could be U-shaped, more prominent in certain subgroups and different between dietary and supplemental form. However, most of the studies were observational, thus could not confirm causality. One clinical trial was performed, but it was not a randomized controlled trial, thus confounding factors could not be excluded.
CONCLUSION: vitamin C may exert beneficial effects on bone, but more rigorous studies and clinical trials should be performed to validate this claim.

Matched MeSH terms: Ascorbic Acid/adverse effects
A 1-h time interval between a meal containing iron and consumption of tea attenuates the inhibitory effects on iron absorption: a controlled trial in a cohort of healthy UK women using a stable iron isotope

Ahmad Fuzi SF, Koller D, Bruggraber S, Pereira DI, Dainty JR, Mushtaq S

Am J Clin Nutr, 2017 Dec;106(6):1413-1421.
PMID: 29046302 DOI: 10.3945/ajcn.117.161364

Background: Tea has been shown to be a potent inhibitor of nonheme iron absorption, but it remains unclear whether the timing of tea consumption relative to a meal influences iron bioavailability.Objective: The aim of the study was to investigate the effect of a 1-h time interval of tea consumption on nonheme iron absorption in an iron-containing meal in a cohort of iron-replete, nonanemic female subjects with the use of a stable isotope (57Fe).Design: Twelve women (mean ± SD age: 24.8 ± 6.9 y) were administered a standardized porridge meal extrinsically labeled with 4 mg 57Fe as FeSO4 on 3 separate occasions, with a 14-d time interval between each test meal (TM). The TM was administered with water (TM-1), with tea administered simultaneously (TM-2), and with tea administered 1 h postmeal (TM-3). Fasted venous blood samples were collected for iron isotopic analysis and measurement of iron status biomarkers. Fractional iron absorption was estimated by the erythrocyte iron incorporation method.Results: Iron absorption was 5.7% ± 8.5% (TM-1), 3.6% ± 4.2% (TM-2), and 5.7% ± 5.4% (TM-3). Mean fractional iron absorption was found to be significantly higher (2.2%) when tea was administered 1 h postmeal (TM-3) than when tea was administered simultaneously with the meal (TM-2) (P = 0.046). An ∼50% reduction in the inhibitory effect of tea (relative to water) was observed, from 37.2% (TM-2) to 18.1% (TM-3).Conclusions: This study shows that tea consumed simultaneously with an iron-containing porridge meal leads to decreased nonheme iron absorption and that a 1-h time interval between a meal and tea consumption attenuates the inhibitory effect, resulting in increased nonheme iron absorption. These findings are not only important in relation to the management of iron deficiency but should also inform dietary advice, especially that given to those at risk of deficiency. This trial was registered at clinicaltrials.gov as NCT02365103.

Matched MeSH terms: Ascorbic Acid/adverse effects