As a sufferer from depression and pretty much unemployed for 2.5 years, I have been feeling a terrible lack of opportunity to be rewarded- either with money or something else I favour. People tell me (and I have started telling myself) not to WANT things. I really do have what I NEED for basic sustenance- sufficient food, a roof over my head, clothing, warmth, a partner, sex, 3 cats and friends. But despite telling myself to concentrate on how lucky I am (ie. think Haitian kids, one of whom I sponsor through World Vision), I have this terribly human trait of WANTING stuff/experiences/different stuff. Well now the people in the labs, those white-coated loonies of popular folklore, have discovered that our brains need enough of a particular substance to actually FEEL rewarded by anything. Not surprisingly, this substance is serotonin, the stuff that your neurons like to bathe in regularly, so you don't feel depressed. These guys (along with a host of others) found that serotonin was the vital part of the brain's REWARD system.
Now, how can we get more rewards? Do things and eat foods that increase the free-floating serotonin levels in the brain. There is a lot of bullshit, "natural", nutrition and New Age claptrap around, but the truth seems to be that foods containing plenty of tryptophan (trip-to-fane) are the go. These are mostly tasty proteiny things like, lean red meat, turkey, chicken, nuts, cheese, beans and pulses (eg. lentils, chick peas). As part of a normal diet, we need to consume these with a little carbohydrate (which is hard to avoid, given the composition of most food)- the more complex ans slower to burn in our systems, the better. So- no added sugar, but good complex carbohydrates such as in vegetables, grainy breads and some fruits. Traditionally they say chocolate and bananas increase serotonin, but they're better with some protein as part of a meal, not an EXTRA snack on the side! Appropriate fats are good too- mono-unsaturated oils like olive oil, omega 3 and 6 oils like fish oil/some nut oils, and recently some authorities have recommended pure cold-pressed coconut oil (which I find good). There seems to be little about dietary coconut oil, except as an antioxidant- by which the scientists mean that the components of coconut oil roam around our blood stream "scavenging" those things called "free radicals" which seem to age us and may play a role in the beginning of cancer. So even if the virgin coconut oil is not yet proven to help with depression and reward experiences, the mere thought that it's doing you good may help anyway!
Now, I'm no medical authority, so don't call me to account for this one, but there were recent reports that a pediatrician (children's doctor) in the USA was treating her prematurely dementing husband with coconut oil and getting promising results. There is nothing in the conventional medical literature as yet, but I'm waiting with interest.
However, leaders in the field of cognition in ageing caution that there is no clear or longterm proof of the worthwhile use of various oils and other substances in slowing brain decline.