8 reasons to be a teetotaller...

Alcohol

The blood-brain barrier is a layer of epithelial cells that line the capillaries. Alcohol floats right through this gatekeeper 30 seconds after entering the bloodstream, disrupting nerve-cell communication. This interference boosts your confidence, shortens your attention span, and makes you say stupid things. Four drinks in 1 hour and you have a blood-alcohol concentration of 0.08, the legal limit in most states.

It's the first stop for alcohol, with 20 percent of any drink entering the bloodstream here within 5 minutes by slipping between the stomach's mucus-producing epithelial cells. The fuller your stomach, the slower the squeeze. Alcohol also jumpstarts the production of hydrochloric acid, which can eat through the stomach's protective mucus. That's why chronic boozers suffer from heartburn, inflammation, ulcers, and bleeding.

After 20 minutes, the remaining 80 percent of alcohol arrives here and diffuses almost instantly into the blood, thanks to millions of microscopic fingers that carpet the intestinal lining. Alcohol blocks the absorption of water and sodium here, which is why a binge dehydrates you. Chronic imbibing interferes with enzymes that break down carbohydrates, proteins, and fats, thus reducing uptake of vitamins, minerals, and essential amino acids. That's why heavy drinkers are often undernourished.

Drink too much in one sitting and you won't be able to think straight below the waist, either. That's because alcohol deadens nerve cells all over the body--the "atten-hut" command gets lost in transit. Also, eight of 10 problem drinkers suffer from chronic erectile dysfunction: A three-drinks-a-day habit causes high blood pressure, restricting bloodflow to the penis, and chronic boozing reduces testosterone production.

It's true that, in certain cases, moderate doses of alcohol may help keep the heart and its arteries clear--one or two drinks a day raises plaque-scavenging HDL cholesterol, softens artery walls, and makes blood cells less likely to clot. Heavier drinking, however, narrows the blood vessels and raises blood pressure, forcing the heart to pump harder. It also can short-circuit the electrical signals, causing an arrhythmia. Ultimately, alcohol abuse damages heart muscle, causing it to pump less efficiently. This can lead to heart failure.

It eventually breaks down 90 percent of blood alcohol, starting to scrub within 10 minutes of your first sip. Blood absorbs alcohol much faster than the liver can eliminate it, which is why it takes an hour for the effects of each drink to wear off. Heavy drinking creates excess free radicals and collagen, a building block of scar tissue. Both crowd out or kill off healthy liver cells.

About 5 percent of blood alcohol quickly diffuses into the air sacs (alveoli) of the lungs. The alveoli warm the liquid alcohol, turning it into a vapor that's exhaled--which is how Breath- alyzers measure blood-alcohol levels. Long-term alcohol abuse depletes an important antioxidant in the lungs, leaving them vulnerable to permanent, life-threatening damage from pneumonia, sepsis, and other infections.