* Herbal medicine. Studies show that Ginkgo biloba can stop some of the major symptoms of cerebrovascular insufficiency. It is especially helpful in early-stage Alzheimer’s, and can slow its progress (Bensky D, Gamble A, Chinese Herbal Medicine: Materia Medica, Seattle: Eastland Press, 1986). Huperzine A, an extract of the moss Huperzia serrata, has proved more effective than tacrine, an acetylcholinesterase inhibitor, in several Chinese and American studies.

* Nutrition. Beta-carotene has enormous protective effects against cognitive decline, according to a study in which 7600 patients supplemented with 50 mg of the carotenoid every other day for 18 years (Proceedings of the 9th International Conference on Alzheimer’s Disease & Related Disorders, Philadelphia, July 2004). Other antioxidants, especially vitamins C and E, can also help, even among smokers, by reducing the overall risk of Alzheimer’s by 20 per cent (JAMA, 2002; 287: 3223-9, 3261-3).

* Folic acid. Alzheimer’s sufferers tend to have raised levels of homocysteine; folic acid along with vitamins B6 and B12 can reduce this. However, there is as yet no evidence to suggest that lowering homocysteine will prevent the disease (N Engl J Med, 2002; 346: 466-8).

* Fish eaten at least once a week can protect against Alzheimer’s. Researchers believe it is the omega-3 polyunsaturated fatty acids (PUFAs) in fish that are protective. PUFAs can also be found in nuts and oils (Arch Neurol, 2003; 60: 940-6).

* Mental health. People who indulge in regular mental exercise were less likely to develop Alzheimer’s. Activities such as reading, playing board and card games, and doing crossword puzzles all can help to ward off Alzheimer’s and dementia (N Engl J Med, 2003; 348: 2508-16). Achieving higher levels of education, or enrolling in adult-education classes can also help (West Indian Med J, 2002; 51: 143-7).