H J Powers
Affiliation: University of Sheffield
- Study Protocol: randomised controlled trial to investigate the functional significance of marginal riboflavin status in young women in the UK (RIBOFEM)Marilyn H E Hill
Human Nutrition Unit, School of Medicine and Biomedical Sciences, University of Sheffield, UK
BMC Public Health 9:90. 2009..Recent National Diet and Nutrition Surveys in the United Kingdom have shown that young women in particular are at risk of moderate riboflavin deficiency and low iron status...
- Recruiting older people to a randomised controlled dietary intervention trial--how hard can it be?Sarah E Forster
Department of Oncology, Faculty of Medicine and Dentistry and Health, The University of Sheffield, Royal Hallamshire Hospital, Glossop Rd, Sheffield, S10 2JF, UK
BMC Med Res Methodol 10:17. 2010..Few published trials include such information and the number of participants screened or approached is not always cited...
- Study protocol to investigate the effect of a lifestyle intervention on body weight, psychological health status and risk factors associated with disease recurrence in women recovering from breast cancer treatment [ISRCTN08045231]John M Saxton
Centre for Sport and Exercise Science, Sheffield Hallam University, Sheffield, UK
BMC Cancer 6:35. 2006....
- Current knowledge concerning optimum nutritional status of riboflavin, niacin and pyridoxineH J Powers
Division of Child Health, University of Sheffield, Sheffield Children s Hospital, UK
Proc Nutr Soc 58:435-40. 1999..It is concluded that whilst there are several biochemical measures which respond to changes in intake of each of these vitamins, no single measure is wholly satisfactory as a marker of optimum status...
- Correcting a marginal riboflavin deficiency improves hematologic status in young women in the United Kingdom (RIBOFEM)Hilary J Powers
Human Nutrition Unit, University of Sheffield, Sheffield, United Kingdom, and the Institute of Food Research, Norwich, United Kingdom
Am J Clin Nutr 93:1274-84. 2011..Moderate riboflavin deficiency is prevalent in certain population groups in affluent countries, but the functional significance of this deficiency is not clear. Studies have indicated a role for riboflavin in the absorption and use of iron...
- Responses of biomarkers of folate and riboflavin status to folate and riboflavin supplementation in healthy and colorectal polyp patients (the FAB2 Study)Hilary J Powers
Human Nutrition Unit, Section of Oncology, University of Sheffield, UK
Cancer Epidemiol Biomarkers Prev 16:2128-35. 2007..Colorectal mucosal folate concentration responds to folic acid supplementation to an extent comparable to that seen in plasma, but with a suggestion of an upper limit...
- Folic acid under scrutinyHilary J Powers
Human Nutrition Unit, School of Medicine and Biomedical Sciences, University of Sheffield, S10 2RX, UK
Br J Nutr 98:665-6. 2007
- Interaction among folate, riboflavin, genotype, and cancer, with reference to colorectal and cervical cancerHilary J Powers
Human Nutrition Unit, University of Sheffield, UK
J Nutr 135:2960S-2966S. 2005..An additional factor determining the effect of diet and genotype interactions on cancer risk may be the stage of cancer development...
- Riboflavin (vitamin B-2) and healthHilary J Powers
Centre for Human Nutrition, The University of Sheffield, United Kingdom
Am J Clin Nutr 77:1352-60. 2003..Riboflavin deficiency may exert some of its effects by reducing the metabolism of other B vitamins, notably folate and vitamin B-6...
- Developments in the measurement of plasma total homocysteineH J Powers
The Centre for Human Nutrition, Division of Clinical Sciences, University of Sheffield, Sheffield, UK
Curr Opin Clin Nutr Metab Care 3:391-7. 2000..Immunoassays and high-performance liquid chromatography methods are currently available in kit form, fluorescence polarization immunoassay showing the best performance...
- Sensitivity of markers of DNA stability and DNA repair activity to folate supplementation in healthy volunteersG P Basten
Human Nutrition Unit, Division of Clinical Sciences North, The University of Sheffield, Northern General Hospital, UK
Br J Cancer 94:1942-7. 2006....
- Reduction in plasma total homocysteine through increasing folate intake in healthy individuals is not associated with changes in measures of antioxidant activity or oxidant damageS J Moat
The Centre for Human Nutrition, University of Sheffield, The Northern General Hospital, UK
Eur J Clin Nutr 57:483-9. 2003..Various mechanisms have been proposed to explain the association between plasma total homocysteine (tHcy) and risk of cardiovascular disease, including oxidative activity of homocysteine...
- Role of aminothiols as a component of the plasma antioxidant system and relevance to homocysteine-mediated vascular diseaseS J Moat
University Division of Child Health, University of Sheffield, Northern General Hospital, Sheffield S5 7AU, UK
Clin Sci (Lond) 100:73-9. 2001..Thus hyperhomocysteinaemia may pose an oxidative stress not only through the direct cytotoxicity of homocysteine, but also from an associated fall in plasma cysteine...
- Effects of methodological variation on assessment of riboflavin status using the erythrocyte glutathione reductase activation coefficient assayMarilyn H E Hill
Human Nutrition Unit, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield S102RX, UK
Br J Nutr 102:273-8. 2009..The details of the EGRAC method should be standardised for use in different laboratories and over time. Additionally, it is proposed that consideration be given to re-evaluating the basis of the EGRAC threshold for riboflavin deficiency...
- Effect of folic Acid supplementation on the folate status of buccal mucosa and lymphocytesGraham P Basten
Human Nutrition Unit, University of Sheffield, Coleridge House, Northern General Hospital, United Kingdom
Cancer Epidemiol Biomarkers Prev 13:1244-9. 2004..Methods have been developed for the rapid measurement of lymphocyte and buccal mucosal total folate. Lymphocyte folate is sensitive to folate intake and is reflected by plasma 5-MeTHF...
- Serum retinoids and beta-carotene as predictors of hip and other fractures in elderly womenMargo E Barker
Human Nutrition Unit, Division of Clinical Sciences North, University of Sheffield, United Kingdom
J Bone Miner Res 20:913-20. 2005....
- Folate status and aberrant DNA methylation are associated with HPV infection and cervical pathogenesisJanet E Flatley
Human Nutrition Unit, Faculty of Medicine, University of Sheffield, Beech Hill Road, Sheffield, S10 2RX, United Kingdom
Cancer Epidemiol Biomarkers Prev 18:2782-9. 2009..05). These findings are compatible with a role for folate in modulating the risk of cervical cancer, possibly through an influence over high-risk HPV infection. DAPK, CDH1, and HIC1 genes are potential biomarkers of cervical cancer risk...
- Riboflavin depletion impairs cell proliferation in adult human duodenum: identification of potential effectorsEmi Nakano
Human Nutrition Unit Faculty of Medicine, Dentistry and Health, The University of Sheffield, Beech Hill Road, Sheffield, S10 2RX, UK
Dig Dis Sci 56:1007-19. 2011..This study aims to establish whether riboflavin deficiency has consequences for gastrointestinal (GI) morphology in adults and what the effects and effectors of any such alteration may be...
- Antioxidant supplementation with or without B-group vitamins after acute ischemic stroke: a randomized controlled trialRajesh Ullegaddi
Sheffield Institute for Nutritional Studies on Ageing and the Human Nutrition Unit, University of Sheffield, Northern General Hospital, Sheffield S5 7AU, UK
JPEN J Parenter Enteral Nutr 30:108-14. 2006..Several studies point to an antioxidant effect of B-group vitamins and a pro-oxidant effect of elevated total plasma homocysteine (tHcy)...
- Folate protects against oxidative modification of human LDLE Nakano
Centre for Human Nutrition, Division of Clinical Science, Northern General Hospital, University of Sheffield, Sheffield S5 7AU, UK
Br J Nutr 86:637-9. 2001....
- Antioxidant supplementation enhances antioxidant capacity and mitigates oxidative damage following acute ischaemic strokeR Ullegaddi
Sheffield Institute for Studies on Ageing and Human Nutrition Unit, The University of Sheffield, Northern General Hospital, UK
Eur J Clin Nutr 59:1367-73. 2005..To test whether supplementary antioxidants immediately following acute ischaemic stroke will enhance antioxidant capacity and mitigate oxidative damage...
- Hyperhomocystinemia in children with inflammatory bowel diseaseEmi Nakano
Centre for Human Nutrition, Division of Clinical Sciences, University of Sheffield, Northern General Hospital, Sheffield, United Kingdom
J Pediatr Gastroenterol Nutr 37:586-90. 2003..The authors studied the link between tHcy and IBD in children, in whom associations may be clearer, and investigated associations with plasma von Willebrand factor antigen, a marker of vascular damage...
- Erythrocyte pyridoxamine phosphate oxidase activity: a potential biomarker of riboflavin status?Sohail Mushtaq
Human Nutrition Unit, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield, United Kingdom
Am J Clin Nutr 90:1151-9. 2009..Because G6PD deficiency is common in parts of the world where ariboflavinosis is endemic, it is important to have a measure of riboflavin status that is unaffected by differences in G6PD status...
- B-group vitamin supplementation mitigates oxidative damage after acute ischaemic strokeRajesh Ullegaddi
Sheffield Institute for Nutritional Studies on Ageing, The University of Sheffield, Northern General Hospital, Sheffield S5 7AU, UK
Clin Sci (Lond) 107:477-84. 2004..05). In conclusion, B-group vitamin supplementation immediately post-infarct may have antioxidant and anti-inflammatory effects in stroke disease independent of a homocysteine-lowering effect...
- Effects of an exercise and hypocaloric healthy eating program on biomarkers associated with long-term prognosis after early-stage breast cancer: a randomized controlled trialE Scott
School of Health and Related Research, University of Sheffield, Sheffield, UK
Cancer Causes Control 24:181-91. 2013..These findings suggest that an individualized exercise and a hypocaloric healthy eating program can positively impact upon health outcomes influencing long-term prognosis in overweight women recovering from early-stage breast cancer...
- Absence of luminal riboflavin disturbs early postnatal development of the gastrointestinal tractC A Yates
The Centre for Human Nutrition, University of Sheffield, The Northern General Hospital, Sheffield, UK
Dig Dis Sci 48:1159-64. 2003..The absence of riboflavin in the duodenal lumen impairs normal development, suggesting that a crypt sensing mechanism may be involved in the response to riboflavin deficiency...
- Downstream effects on human low density lipoprotein of homocysteine exported from endothelial cells in an in vitro systemE Nakano
Human Nutrition Unit, University of Sheffield, Coleridge House, The Northern General Hospital, Sheffield S5 7AU, United Kingdom
J Lipid Res 46:484-93. 2005..Factors that regulate intracellular Hcy metabolism modulate these effects...
- Copper-mediated LDL oxidation by homocysteine and related compounds depends largely on copper ligationEmi Nakano
Centre for Human Nutrition, Division of Clinical Sciences, University of Sheffield, Northern General Hospital, Herries Road, Sheffield S5 7AU, UK
Biochim Biophys Acta 1688:33-42. 2004..The likely role of homocysteine in LDL oxidation in vivo is discussed in the light of these results...
- The proteolytic profile of prelabour ruptured amnion at term: a case-control studyEmma L Stuart
Human Nutrition Unit, University of Sheffield, Northern General Hospital, Coleridge House, Herries Road, Sheffield S5 7AU, UK
Eur J Obstet Gynecol Reprod Biol 131:158-62. 2007....
- Reduced collagen and ascorbic acid concentrations and increased proteolytic susceptibility with prelabor fetal membrane rupture in womenEmma L Stuart
Human Nutrition Unit, University of Sheffield, Sheffield S5 7AU, United Kingdom
Biol Reprod 72:230-5. 2005..The formation of the rupture initiation site is a function of a regional variation in collagen cross-link ratio. Tissue ascorbic acid status may be an important mediator of these processes...
- Effect of riboflavin status on the homocysteine-lowering effect of folate in relation to the MTHFR (C677T) genotypeStuart J Moat
Cardiovascular Sciences Research Group, Wales Heart Research Institute, University of Wales College of Medicine, Cardiff, Wales CF14 4XN, United Kingdom
Clin Chem 49:295-302. 2003..It has been proposed that riboflavin may act together with folate to lower plasma tHcy, particularly in individuals with the thermolabile MTHFR T variant...
- Methylenetetrahydrofolate reductase 677C-->T genotype modulates homocysteine responses to a folate-rich diet or a low-dose folic acid supplement: a randomized controlled trialPauline A L Ashfield-Watt
Cardiovascular Sciences Research Group, Wales Heart Research Institute, University of Wales College of Medicine, Cardiff, Wales, United Kingdom
Am J Clin Nutr 76:180-6. 2002..Low folate status and elevated plasma homocysteine are associated with increased risk of neural tube defects and cardiovascular disease. Homocysteine responses to folate may be influenced by genetic variants in folate metabolism...
- Emerging diet-related surrogate end points for colorectal cancer: UK Food Standards Agency diet and colonic health workshop reportPeter Sanderson
Nutrition Division, Food Standards Agency, London, UK
Br J Nutr 91:315-23. 2004....
- Homocysteine from endothelial cells promotes LDL nitration and scavenger receptor uptakeHelen R Griffiths
Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
Free Radic Biol Med 40:488-500. 2006..The present studies suggest that elevated plasma tHcy may promote LDL nitration and increased scavenger receptor uptake, providing a molecular mechanism that may contribute to the clinical link between CVD and elevated plasma tHcy...
- Quantification of the bioavailability of riboflavin from foods by use of stable-isotope labels and kinetic modelingJack R Dainty
Institute of Food Research, Norwich, United Kingdom
Am J Clin Nutr 85:1557-64. 2007..One reason for this may be an overestimate of the bioavailability of riboflavin from foods, about which relatively little is known...
- Letter by Powers et al regarding article, "Riboflavin lowers homocysteine in individuals homozygous for the MTHFR 677C-->T polymorphism"Hilary J Powers
Circulation 114:e65; author reply e66. 2006