I've often wondered how much diet plays a role in "mental acuity." When he referred to poor children being adopted into upper middle class families that was the first thing that came to mind.

It's a very big role, especially in early childhood. As the parent points out iodized salt is a big one, another is omega 3 oils.

Also useful is getting enough calories every day.

Omega-3 needs to be balanced against Omega-6, but there isn't agreement on the ratio. They're polyunsaturated fats, which I try to limit. But I aim for a 1:1 ratio.

Omega-3 is anti-inflammatory, the Omega-6 pro-inflammatory. They're both essential to bodily processes, even though O-6 is pro-inflammation.

Good sources of O-3: Fish Oil, Krill Oil, Salmon Oil

I read 1:6 (O-3:O-6) is supposedly balanced, no ill effect or positive effects. 1:4 is considered good, but aiming for a 1:1 is definitely a good target.

The thing I find most disturbing is that omega-6 can replace monounsaturated fats in your skin and could significantly increase your risk of cancer. I'm unsure of how exactly, but the polyunsaturated fats increase the free radical production, where as monounsaturated and saturated fats can prevent it. Not to mention polyunsaturated fats might inhibit vitamin D production.

Another thing to consider, omega-6 can inhibit your immune system, which further increases your risk of cancer. It just kicks you when you're down, not only can O-6 cause cancer, but it can stop your body fighting it too.

O-6s also down regulates thyroid function, decreasing metabolism.

http://wholehealthsource.blogspot.com/2008/12/omega-6-linole...

I didn't want to mention sat fat benefits, because I hate making heretical claims without time to back up them up, but I agree.

Even the AHA has admitted that stearic acid, a sat fat, is fine. As we turn up the power of the microscope on nutrition, sat fats suddenly aren't blanket bad for you. It looks like I depends on the form, source and context you're eating it. I try to down a lot of coconut milk/oil. It's a healthy sat fat, a MCT that's burned immediately instead of stored as fat.

The AHA promotes O-6s by the way. It seem like there's a lot of cached thought in nutrition. Many in the field can't design a study. They test a "high-fat diet" without thinking it matters what fats were eaten, and in what form.

Sodium is important to brain function. It's recently been linked with antidepressant properties:

http://www.scientificblogging.com/news_releases/salt_may_be_...