I think it's timely in that we have other studies showing a connection between, for example, overweight or obesity and dementia risk, said Dr. Gary Small, director of the UCLA Longevity Center and co-author of The Alzheimer's Prevention Program (Workman Publishing, 2011). You can see there is clearly a connection between what we eat and how well we think as we age. If confirmed, the findings of the study could allow doctors to determine whether patients with low levels of nutrients should add certain foods to their diet to protect against cognitive decline, Small said.

There are components of a brain-healthy diet that research points to, including omega-3-rich fish and nuts like walnuts, antioxidant fruits and vegetables, whole grains and avoiding processed foods and dairy products and meats rich in omega-6 fats, Small said. If you look at some of the nutrients measured in this study, it certainly is consistent with what we know about a healthy brain diet.

The default assumption is that diet is affecting brain aging, but it could also be the case that brain aging is affecting diet, said Rhoda Au, a dementia and aging researcher at Boston University. Au said that there is also some indication that a very low body weight can hurt  cognition, the result of weight loss and lack of nutrition.

But one of the important findings was that it seemed to be foods in combination, rather than individual vitamins, that were helping brain power, and so recommendations for the future would likely focus on foods rather than vitamin supplements. The take-home message from this study is the concept of a balanced diet, rather than a single source of nutrients, Au said.

Dr Simon Ridley, head of research at Alzheimer ™s Research UK, welcomed the study, although noted that it was a small sample of people and the researchers did not investigate whether these people went on to develop Alzheimer ™s. He said, One strength of this research is that it looked at nutrients in people ™s blood, rather than relying on answers to a questionnaire. Although there is no sure-fire way of preventing Alzheimer ™s yet, we know that risk factors for heart disease and stroke can also increase the risk of dementia. The best advice at the moment is to eat a balanced diet with plenty of fruit and vegetables, and keep healthy by not smoking, taking regular exercise and keeping blood pressure and cholesterol in check. Currently 820,000 people are affected by dementia in the UK and with a rapidly ageing population, those numbers are expected to soar. We urgently need to find ways to prevent dementia if we are to head off a future crisis, and that means it ™s vital to invest in research, he said.