Our brains work best on the prehistoric diet that shaped their evolution. However, our modern diet is a far cry from that of our ancestors. For generations, hunters and gatherers survived on wide game, wild greens, fruits, berries and roots. The typical western diet, on the other hand, includes large quantities of processed and fast foods.

Jean Carper in her book Your Miracle Brain found that, compared to a stone age diet, we consume:

One tenth the amount of fibre

A similar amount of carbohydrates but only one quarter as much from fruits and vegetables (the rest tends to be empty calorie sugars)

One third the amount of potassium and almost seven times the amount of sodium (or a ratio of potassium to sodium of roughly 1-2 instead of the preferred 10-1)

Research has shown that this modern diet hampers mental performance and can lead to serious long term deterioration of our brains. In particular, two of the major culprits in this mental deterioration are too much sugar and too few antioxidants.

How Sugar Affects the Brain

The Problem of Too Much Glucose

Glucose, the form of sugar that circulates in the blood, is critical to optimal functioning of the brain. Indeed, glucose is the brains exclusive source of fuel. Deficiencies in glucose levels can cause the brain to slow down and malfunction. This blood sugar comes from the foods we eat, particularly from carbohydrates such as sweets and starches.

The trick is to make sure that we produce the right amount of glucose to suit our brains requirements. For instance there is evidence that more glucose is burned when the brain is working hard to solve a problem. So in some cases, a quick boost in blood sugar levels may be helpful when the brain is active. However, the bigger problem for most westerners is not having sufficient glucose but having too much.

The diet of most westerners includes many carbohydrates that are quickly converted to glucose. This constant high level of glucose triggers the production of insulin whose job is to allow the glucose to move from the blood and into the cells where it is needed. If the glucose levels are too high, insufficient insulin can be produced to do the job properly. Over time, the cells react by becoming less sensitive to insulin putting more and more strain on the pancreas to make more insulin. This vicious cycle sets the stage for Type 2 diabetes in adults. It also can lead to a number of conditions that affect cognitive function including a thickening of the carotid artery going to the brain and high blood pressure. It is thought that this high glucose/insulin combination affects IQ levels, memory, learning and general brain function.

Getting the Right Amount of Glucose

So how do we prevent this glucose overload? One of the key methods is to pick foods that are converted to glucose slowly which allows the pancreas to keep up with the insulin needs and prevents the development of insulin resistance. In particular, it is important to choose the carbohydrates you eat carefully. Its not that all carbohydrates are bad. Its just that some create sharp rises in blood glucose while others break down gradually and help regulate the flow of glucose to the brain. Not surprisingly, the fast or high glycemic carbohydrates include items like refined sugars and cookies. But the list of high glycemic foods is not obvious and includes most breads, rice, packaged cereals, and potatoes. On the other hand, foods such as legumes, nuts, pasta, low fat dairy products, most fruits and vegetables are good at delivering a controlled amount of glucose to the cells.

Antioxidants and the Brain

Free radicals are formed when glucose and oxygen are burned. Much has been written about the damage that free radicals can do to the body. However, the brain is particularly susceptible since it burns more oxygen and glucose than any other organ. (and produces lots of free radicals). Free radicals cause problems in the brain by eating through the defensive layers of the brain cells and destroying neurons. It doesnt help that the neuron membranes are made of fatty acids that react strongly to the free radicals.

Antioxidants are substances that neutralize the free radicals to stop this cell destruction. They include vitamins C & E as well as beta-carotene and many others. The best way to get these antioxidants working for you is by eating lots of fruits and vegetables. In particular the top ten sources of antioxidants are:

1. Prunes
2. Raisons
3. Berries
4. Garlic
5. Spinach
6. Brussel sprouts
7. Plums
8. Alfalfa sprouts
9. Broccoli
10. Beets

Other important antioxidants include:

Lycopene This potent antioxidant is found in tomatoes and tomato products such as tomato paste, sauce, soup and juice

Tea Drinking tea can provide your brain with a quick source of antioxidants. Black or green tea are good but instant teas, bottled teas or herbal teas have little protective value.

Wine Light drinking (about one drink/day) provides a beneficial level of antioxidants that prevents the decay of brain cells. Red wine in particular, has a high level of antioxidants. On the other hand, excessive drinking is harmful to the brain so you might want to try grape juice as a non-alcoholic alternative.

Chocolate The good news is that chocolate can be good for you. Pick dark chocolate rather than milk chocolate to maximize the antioxidant content.

It appears that eating smart is not only good for general health, but can improve thinking, creativity, learning ability and memory while staving off long term mental deterioration.