Volume 89, Issue 4, April (2003), pp. 483-490 © The Author 2003
doi:10.1079/BJN2002804

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Low serum cholesteryl ester-docosahexaenoic acid levels in Alzheimer’s disease: a case–control study

A. M. Tully¹, H. M. Roche^1,*, R. Doyle², C. Fallon², I. Bruce², B. Lawlor², D. Coakley² and M. J. Gibney^1
1Unit of Nutrition, Department of Clinical Medicine, Trinity Centre for Health Sciences and 
²The Mercer’s Institute for Research in Ageing, St James Hospital, Dublin 8, Republic of Ireland

 (Received 20 December 2001–Revised 31 October 2002–Accepted 6 November 2002)

Low n-3 polyunsaturated fatty acid (PUFA) status may be associated with neuro-degenerative disorders, in particular Alzheimer’s disease, which has been associated with poor dietary fish or n-3 PUFA intake, and low docosahexaenoic acid (DHA) status. The present case–control study used an established biomarker of n-3 PUFA intake (serum cholesteryl ester-fatty acid composition) to determine n-3 PUFA status in patients with Alzheimer’s disease, who were free-living in the community. All cases fulfilled the National Institute of Neurological and Communicative Disorders and Stroke and Alzheimer’s Disease and Related Disorders Association criteria for Alzheimer’s disease. Detailed neuropsychological testing and neuroimaging established the diagnosis in all cases. The subjects (119 females and twenty-nine males) aged 76·5 (sd 6·6) years had a clinical dementia rating (CDR) of 1 (sd 0·62) and a mini mental state examination (MMSE) score of 19·5 (sd 4·8). The control subjects (thirty-six females and nine males) aged 70 (sd 6·0) years were not cognitively impaired (defined as MMSE score <24): they had a mean MMSE score of 28·9 (sd 1·1). Serum cholesteryl ester-eicosapentaenoic acid and DHA levels were significantly lower (P<0·05 and P<0·001 respectively) in all MMSE score quartiles of patients with Alzheimer’s disease compared with control values. Serum cholesteryl ester-DHA levels were progressively reduced with severity of clinical dementia. DHA levels did not differ in patients with Alzheimer’s disease across age quartiles: all were consistently lower than in control subjects. Step-wise multiple regression analysis showed that cholesteryl ester-DHA and total saturated fatty acid levels were the important determinants of MMSE score and CDR. It remains to be determined whether low DHA status in Alzheimer’s disease is a casual factor in the pathogenesis and progression of Alzheimer’s disease.

Abbreviations: AD; Alzheimer’s disease; CDR; clinical dementia rating; DHA; docosahexaenoic acid; MMSE; mini mental state examination; PUFA; polyunsaturated fatty acid
Corresponding Author: Dr Helen M. Roche, fax +353 1 454 2043, email hmroche@tcd.ie

Keywords:
Alzheimer's disease: Docosahexaenoic acid: n-3 Polyunsaturated fatty acids