Most of us know someone touched by dementia because it affects more than 400,000 Australians, and Alzheimer's disease (AD) accounts for about 80 per cent of these cases. There is optimism for a pharmaceutical treatment by 2025 that may slow the progression of AD, but at present supplements are sought out to treat or prevent the disease.

During the past few decades, several nutritional supplements have emerged as candidates for the treatment of AD. In the '90s, ginkgo biloba appeared, followed by the B vitamins in the noughties. Unfortunately, neither of these supplements was effective enough to be recommended for the prevention of AD. B vitamins have been shown to lower homocysteine, one of the risk factors in blood for AD, but even when homocysteine is lowered in older adults, symptoms of AD are still present.

Omega-3 fatty acids, commonly consumed in fish oil supplements, followed the B vitamins. Earlier this year, the results of a three-year study of fish oil supplementation in 1600-plus older adults were revealed, with again no benefits in the prevention of AD.

Research in the field of nutrition is challenging, and the search for a "magic bullet" supplement to prevent AD may be futile. However, dietary patterns, such as the Mediterranean diet, have been linked with a variety of benefits for overall health, including improved cognitive function.

Last year, Oxford University published promising findings suggesting that B vitamins can slow cognitive decline in older adults with higher blood levels of omega-3 fatty acids.

For now, one can obtain these nutrients through consuming fish, red meat, and leafy green vegetables.

Research is also ongoing to determine the benefits to brain energy metabolism of specific fatty acids found abundantly in the ever-controversial coconut.

Overall, time will tell if supplements can help ward off AD but in the meantime, avoiding junk foods, getting off the couch for some regular exercise, and maximising your social interactions, are some of the best strategies. Also, be sure to avoid the fake science and marketing promotions. If it sounds too good to be true, it probably is.

Response by: Nathan D'Cunha, A/Prof Andrew McKune and Dr Nenad Naumovski, Faculty of Health, University of Canberra

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