To the General Practitioner for Patrick Holford,Patrick Holford D.O.B. 4/5/1953,4/5/1953

Date 12/07/2020

Board of Trustees

Dr Rona Tutt – Chair OBE PhD

Professor David Russell

Maro Limnios LLB DipION

Michael Metcalfe MSc, DMS

Scientific Advisory Board

Professor David Smith – Chair DPhil FMedSci

Professor Helga Refsum MD PhD

Professor Peter Ryan BA MPhil DProf

Professor Sube Banerjee MSc FRCPsych

Professor Jeremy P E Spencer BSc PhD

Your patient has completed the Cognitive Function Test at, an educational trust whose mission is to promote the link between mental health and nutrition. This is a digital screening test for those aged 50 and above, designed to detect early cognitive impairment. This test has been developed with Professor Timothy Salthouse and Dr Celeste de Jager, specialists in assessment of cognitive function. It has been validated against the paper and pencil test as a reliable measure of cognitive performance for those between the ages of 50 and 70 years in the three cognitive domains known to be sensitive to, or predictive of, Alzheimer’s disease: episodic memory, executive function and processing speed. As such, it provides a sensitive objective assessment of cognitive performance when clinical symptoms of impairment may be undetectable. Given that the progression from the first signs of cognitive impairment to Alzheimer’s disease may take up to 30 years, early screening and preventive action is imperative.

Your patient's Cognitive Function Test results indicate that they performed slightly below the norm for their age. Poor cognitive test scores may reflect early changes in brain function or may be due to other factors including heart disease, a history of stroke, epilepsy, Parkinson’s disease, thyroid disease, B12 deficiency, medication, depression, acute infection and chronic stress. There is now a substantial body of evidence, referenced below, that an individual’s plasma homocysteine level is a reliable indicator of risk for cognitive impairment and Alzheimer's disease, that it correlates with both the rate of brain shrinkage and memory decline, and, most importantly, that these may be reversible by supplementing amounts of vitamin B6, B12 and folic acid not achievable by diet alone. It may be advisable to consider screening your patient for homocysteine and to act accordingly if their level is above 9.5 micromol/l, which is the level that correlates with accelerated brain shrinkage and memory decline in published research. Homocysteine testing is also available privately, as a home-test from

The web page provides information for clinicians about the evidence base and also about the clinical recommendations for those with raised homocysteine levels.

If you would like to find out more about our Alzheimer’s Prevention 'Plan B' Project please visit

Yours sincerely,

Dr Rona Tutt OBE

Chair, Food for the Brain Board of Trustees


Trustram-Eve C & de Jager C ‘Piloting and validation of a novel self-administered onlinecognitive screening tool in normal older persons: theCognitive Function Test, International Journal of Geriatric Psychiatry, in press

Smith A D (2008) ‘The worldwide challenge of the dementias: a role for B vitamins and homocysteine?’, Food Nutr Bull, 29(2 Suppl):S143–72

Van Dam F & Van Gool W A (2009) ‘Hyperhomocysteinemia and Alzheimer’s disease: A systematic review’, Archives of Gerentology and Geratrics, 48: 425-430

Oulhaj A et al. (2010) ‘Homocysteine as a predictor of cognitive decline in Alzheimer’s Disease’, Int J Geriatric psychiatry, 25(1): 82-90

Smith A D et al. (2010) ‘Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: a randomized controlled trial’ Public Library of Science ONE, 5(9)

Douaud G et al (2013) ‘ Preventing Alzheimer’s disease-related grey matter atrophy by B-vitamin treatment’ Proc Natl Acad Sci USA. 2013 Jun 4;110(23):9523-8. doi: 10.1073/pnas.1301816110. Epub 2013 May 20

Sachdev P S (2011) ‘Homocysteine and Alzheimer’s disease: an intervention study’ Nature Rev. Neurology 7, 9-10