In February 2018, the Scientific Advisory Committee on Nutrition (SACN) published its position statement on the current evidence on diet, cognitive impairment and dementia.8

Government advice to reduce the risk of developing dementia has included to eat a healthy diet, as well as other non-dietary aspects. In drawing up the position statement, SACN evaluated the evidence in terms of:

·       the overall diet and dietary pattern;

·       specific nutrients (B vitamins, vitamins C and E and omega-3 fatty acids);

·       other dietary components (polyphenols, flavonoids and caffeine) where there has been sufficient research carried out in relation to cognitive impairment and dementia, to allow a preliminary assessment.

There was insufficient evidence on the value of iodine, zinc, copper or protein to allow a preliminary assessment.

Overall, SACN found the evidence base for diet and dietary supplementation to be very limited in relation to cognitive decline. In part, this was because much of the available evidence is based on observational studies, with no controls for confounding factors, such as childhood cognitive ability.

SACN said: €The reviewed literature suggests that adherence to a Mediterranean dietary pattern is associated with a reduced risk of mild cognitive impairment and dementias, including Alzheimer's disease.€ However: €There was no evidence of protective effects for any of the individual nutrients thought to account for the health benefits of Mediterranean dietary patterns.€

It has said further evidence will be needed €to establish whether this association signifies a protective effect of a Mediterranean dietary pattern, or of specific dietary components of such a pattern.€