What foods enhance our thinking and creativity and which ones destroy our mental performance?

There is much evidence that our modern diet is having a major effect on the functioning of our brains. Research has shown that our brains actually work best on the prehistoric diet that shaped their evolution.

For generations, hunters and gatherers survived on wide game, wild greens, fruits, berries and roots. However, this diet has changed dramatically in more modern times. The typical western diet today revolves around large quantities of processed and fast foods. The nutritional difference between our ancestors diet and our current one is striking, particularly in the type of fats that we eat. These differences were examined by Jean Carper in her book Your Miracle Brain. She found that, compared to a stone age diet, we consume:

50% more total fats

Twice as much saturated fats (found in animal products domestic beef contains about 25% fat compared to only 4.3% fat in wild game)

Up to twenty times the amount of omega-6 fats (found in processed oils) compared to the more healthful omega-3 fats (found in fish)

Saturated Fats

One of the most serious issues affecting brain function is the effect of eating the wrong fats. Animal studies have shown that diets high in saturated fats actually cause physical changes in the shape of the brain cells. It is also thought to affect the way that insulin works to control glucose levels, causing disturbances in glucose utilisation in the brain. According to these studies, the result is various forms of cognitive impairment including much poorer memory and learning skills. Furthermore, the effects were found to be cumulative so that the longer you eat high amounts of saturated fats, the higher the risk of impaired learning ability.

Omega-6 vs. Omega-3 fats

And its not just saturated animal fats that can cause problems. Even with vegetable oils there is a big difference in the way different types of oil affect the brain. Our ancestors ate a diet that was roughly equal between two types of polyunsaturated fats omega-6 fats (from fruits, vegetables, nuts and legumes) and omega-3 fats (from seafood). This ideal ratio has changed in our modern diet with the introduction of processed oils which are used in many of our foods and are high in omega-6. Consequently our intake of omega-6 has increased dramatically.

At the same time, our consumption of seafood has diminished. The result is that this omega-6/omega-3 ratio has skyrocketed from 1-1 to almost 20-1. So why is this a problem? Excessive omega-6 has been shown to cause persistent inflammation of brain tissue. Over time, this inflammation can play havoc with your brain, damaging brain cells, cerebral blood vessels, and nerve transmission. The result is impaired brain functioning and memory loss.

So what are the good and bad oils? The oils that are highest in omega-6, and should be avoided, are safflower, sunflower, corn, soy, and walnut. Many of these are commonly found in margarines, salad dressings and processed foods. Better alternatives are olive, canola and flaxseed oils.

It is generally considered that the ratio of omega-6 to omega-3 is more important than the actual amounts of the fats consumed. So the other way to improve the score is to increase the amount of omega-3 fats that we consume. In fact, omega-3 is looking to be a kind of wonder nutrient for the brain. Omega-3 fats seem to work by making the thin fatty membranes that surround the nerve cells in the brain more flexible. This allows more neurotransmitters to be successfully transmitted between nerve cells, increasing our ability to think faster and concentrate better. Omega-3 has also been shown to have a number of secondary effects that control harmful inflammation and even prevent depression.

Omega 3 and Fish

Fish is one of the best sources of omega 3 fats. However, not all fish are created equally when it comes to omega-3 content. There are actually two main components of omega-3 fats DHA and EPA. While both are beneficial, DHA is the more powerful player in brain chemistry and some fish have higher DHA levels than others. The winners in the DHA list of fish include:
Mackerel
Herring
Sardines
Salmon
Tuna.

On the other hand, some fish such as cod, flounder, haddock, snapper, swordfish and shellfish contain little omega-3.

While we may not be able to match the 1-1 ratio of the cavemans diet, it is recommended that we try not to exceed a 4-1 ratio of omega-6 to omega-3 fats by restricting our intake of high omega-6 oils and increasing the amount of high omega-3 fats from fish.