Thursday, August 28, 2008

Carbohydrates


Carbohydrates are the principal source of the body's energy and are divided into two types —simple and complex. Simple carbohydrates include the various sugars found in fruit (fructose), milk (lactose), and table sugar (sucrose). Complex carbohydrates are found in vegetables, whole grains, and legumes. Complex carbohydrates are preferable, as it takes longer for the body to break them down, releasing the sugar into the bloodstream slowly. Simple carbohydrates, especially table sugar, can flood the body and trigger an oversecretion of insulin by the isles of Langerhans, resulting in an initial surge of energy from the sugar followed by lethargy caused by the sudden rush of insulin. Foods should be unrefined, fresh, and natural; refined foods, canned goods, and snack foods should be avoided.

Food Sources: Fruits, whole grains, vegetables.

Effects: Carbohydrates help relax the brain and are necessary for good mental functioning. They act as an antidepressant for people with less sugarinduced serotonin in the brain than normal (such as those who suffer from seasonal affective disorder [SAD]), possibly by amplifying serotonergic neurotransmission. If consumption is timed right, they can increase the brain's energy levels, as they are readily broken down into glucose, a simple sugar found in nature that is necessary for the brain's functioning.

Precautions: Fructose does not have this calming effect. Simple sugars (table sugar, brown sugar, and honey, for instance) have no nutritional value except for calories, and can promote cavities, cause rapid changes in blood sugar and insulin, and lead to obesity, hypoglycemia, and diabetes, among other disorders. Some people are "carbohydrate cravers," and need them to prevent drowsiness, restlessness, or boredom; instead of becoming sleepy, these people become more focused and alert, and better sustain concentration. Carbohydrates are safe and, to quote Dr. Stuart Berger, "They are the only food category not linked to any killer diseases."

Dosage: 300 to 400 g/day from complex carbohydrates, or about 1200 to 1600 kilocalories/day (out of an average total of 1800 to 2200 kilocalories/day). Ideally, 65 percent of a person's caloric intake should be carbohydrates —55 percent from complex carbohydrates and starches and 10 percent from natural sugars such as those found in fruit. A minimum of 50 g/day are needed to prevent ketosis, an acidic condition of the blood. For best effect, carbohydrates should be taken with as little protein and fat as possible, as these slow down or hinder serotonin on its way to the brain.

No comments: