"You're never too old to become younger!" Mae West
How convinced am I that the omega-3s, and DHA in particular, really do slow down or even prevent the cognitive decline we assume to be a normal part of ageing? Until two years or so ago, I hadn't fully made up my mind. Some studies appeared to point strongly in this direction but they were contradicted by one or two studies that appeared to show the very opposite. The contradictory studies were fewer and appeared to point in bizarre directions, such as consumption of saturated fat was good for brain function. I'm afraid the evidence against that is so strong it made such claims suspect to me.
Over recent years, and in most tellingly in 2007, a series of high quality observational studies pointed strongly in the right direction and in 2010, in a paper soon to be published in the journal, Alzheim'er's Disease and Dementia, Yurko-Mauro and colleagues have shown, for the first time in an interventionist study of treating people who already have cognitive decline with pure DHA, that it really does have beneficial effects in this otherwise untreatable condition.
What about the dose-benefit effect of omega-3s, and DHA in particular, shown in the most recent studies?
I have to admit that this was one of the key factors in the new studies that helped me make up my mind. Dose-benefit effect is a well-known and highly-regarded observation in medical and pharmacological studies.
It is important to grasp that maximum benefit is likely to come from taking omega-3s, and DHA in particular, long before cognitive decline sets in. Many doctors, such as myself, suspect that cognitive decline (and Alzheimer's disease) begins long before it become clinically manifest, perhaps as early as the forties -- and certainly by the fifties. Whether you take your omega-3s as oily fish in your diet, or as fish oil or omega-3 supplements, you shouldn't regard yourself as taking a drug-style of treatment, but rather that you are restoring the nutritional balance of your diet to normal.
What about taking omega-3s as treatment in people who, tragically, have already developed symptoms of cognitive decline?
Yes! I would strongly sanction this.