Prevention works, but the Minister must get his facts right about vitamin B12
David Oliver commended the Minister of Health and Social Care for highlighting the importance of prevention, but surely we would expect the Minister to get his facts right.
In his speech on November 5th to the International Association of National Public Health Institutes, Matt Hancock mentioned the importance of targeted preventions. He cited as an example “diagnosing a susceptibility to dementia due to a vitamin deficiency”  but in an interview on the same day, reported in The Times  and other newspapers, he said “A vitamin B12 deficiency leads to a higher instance of dementia but can be prevented by eating broccoli.” The Minister did not seem to know that neither broccoli nor any other vegetable or fruit contains vitamin B12, which is only synthesized by certain bacteria and is obtained in our diet from sources, such as fish and meat, that are exposed to such bacteria in life, or from breakfast cereals that are fortified with the vitamin. 
The Minister’s statement about broccoli might seriously mislead the public, but nevertheless it is encouraging that he has reminded us that nutrition is an important factor in the prevention of dementia  and that B12 insufficiency in particular is a risk factor. There is evidence from a clinical trial that supplementation with B12 markedly slows the rate of brain atrophy and of cognitive decline in those with low-normal levels of B12.  Such an intervention in elderly with cognitive impairment would be a highly cost-effective preventive measure  and the Department might consider adopting this policy.
 Department of Health and Social Care, Prevention is better than cure—Matt Hancock’s speech to IANPHI. 5 Nov 2018, https://www.gov.uk/government/speeches/prevention-is-better-than-cure-ma...,
 Elliott F https://www.thetimes.co.uk/article/matt-hancock-hails-health-prevention-... 5 Nov 2018
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 Smith AD, Refsum H (2017) Dementia prevention by disease-modification through nutrition. J Prev Alz Dis 4, 138-139.
 Douaud G, Refsum H, de Jager CA, Jacoby R, et al. (2013) Preventing Alzheimer's disease-related gray matter atrophy by B-vitamin treatment. Proc Natl Acad Sci U S A 110, 9523-9528.
 Tsiachristas A, Smith AD (2016) B-vitamins are potentially a cost-effective population health strategy to tackle dementia: Too good to be true? Alzheimers Dement (N Y) 2, 156-161.
Competing interests: I consult for Merck Selbstmedikation GmbH and Aprofol AG and am named as inventor on patents US6008221, US6127370, US9364497B2 and on a patent application pending PCT/GB2015/050786.