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Homocysteine in Alzheimer's disease: role of dietary folate, vitamin B6 and B12
Author(s) -
Nilforooshan Ramin,
Broadbent David,
Weaving Gary,
Gurton Jill,
Moore Vanessa,
Houston Lesley,
Tabet Naji
Publication year - 2011
Publication title -
international journal of geriatric psychiatry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 129
eISSN - 1099-1166
pISSN - 0885-6230
DOI - 10.1002/gps.2666
Subject(s) - general partnership , foundation (evidence) , unit (ring theory) , cognition , medicine , library science , sociology , psychology , political science , psychiatry , law , computer science , mathematics education
Homocysteine (Hcy) is an amino acid produced in the body from dietary methionine. The subsequent metabolism of Hcy is dependent on folate, vitamin B6 and vitamin B12. Deficiencies in any of these vitamin cofactors can result in hyperhomocysteinemia (Refsum et al., 2006). Likewise, increased concentrations of plasma Hcy have been linked with the severity of cognitive impairment and poor performance for combined verbal and working memory (Adunsky et al., 2005). The relationship between AD and Hcy is complicated by the role of aging. It has been suspected that the plasma Hcy levels appear to relate more to aging than to cognition (Li et al., 2008). High dose supplementation of VitaminB6, B12 and folate lowers plasma Hcy concentration in AD patients (Aisen et al., 2008). In fact, even in the absence of vitamin deficiency, Hcy levels can be reduced by administration of high-dose supplements of folic acid and vitamins B6 and B12 (Nilsson et al., 2006). However, there is also contradictory data on whether such supplementation slows down cognitive impairment. Therefore, the aim of this study is to evaluate plasma Hcy concentration in AD and control participants in relation to relevant dietary vitamin intake obtained through the use of a 4-day diet intake record. Serum concentration of folate and vitamin B12 was also measured. Patients taking part in the study were 65 years of age or older and were recruited through the memory clinic service in East Sussex, United Kingdom. All patients included were diagnosed with mild to moderate AD according to (NINCDS-ADRDA) Criteria. Controls were partners of recruited patients who had no diagnosis of dementia and had normal scores on MMSE. All participants taking part in the study consumed a varied diet and did not have any acute illness as to interfere with their routine dietary intake. Furthermore, participants did not have any disorders that might have interfered with food intake and absorption. In total 26 patients and 26 controls were recruited to the study. Participants taking part were then provided with food record sheets and they were supported by dietitians through a special telephone help-line to ensure correct completion of the food diaries easy to read accompanying instructions. A 4-day diet intake record food ‘diary’ record method was employed to quantitatively measure the mean daily intake of folate, vitamin B12 and vitamin B6 by each of the participants. Food intake was measured on three representative weekdays and one weekend day. Qualified dietitians assessed all food diaries obtaining the weight of food consumed.