Why You Should Drink Water: Find Out How Water Affects Your Health And Your Body

Water For Cancer Prevention

Very, very few people actually die of dehydration, but the benefits of adequate hydration are a lot greater than most people suppose. French scientists discovered this by feeding lab rats bacon.

Bacon as a Cure for Cancer?

Professors Géraldine Parnaud, Sylviane Taché, Ginette Peiffer, and Denis E. Corpet at the Laboratoire Sécurité des Aliments in Toulouse, France, wanted to conduct an experiment. They set out to determine whether red meat, such as cured pork or roast beef, was more or less likely to contribute to the development of cancer than white meat, such as chicken breast.

The French scientists devised an experiment in which they fed laboratory mice their regular "mouse chow" plus olive oil and milk protein, lard and milk protein, chicken with skin, beef, or bacon. They would observe which mice were more likely to develop colon cancer.

The French scientists were stymied to explain the results of the trial when they observed that the mice who ate a 60% bacon diet were the least likely to develop colon cancer. Rather than issue a statement to feed headlines reading "French Scientists Discover That Bacon Cures Colon Cancer!" the research team took a closer look at the behavior of the mice in their study.

The mice that ate bacon, it turned out, also drank 30% more water. Increasing consumption of water flushed their gastrointestinal tracts of cancer-causing nitrates and nitrites, leading to the paradoxical finding that a high-bacon diet was more cancer-protective than a low-fat diet. The key to success, however, was not the bacon, but the additional consumption of water.

Studies of humans, rather than lab rats, have failed to find any protective effect from eating bacon, but they find significant cancer-protective effect from drinking water. The often-repeated advice to drink at least eight glasses of tap water a day really does not have a basis in science. Some research in Asia has found benefits stop at drinking just five or six glasses (at least 1.5 liters) of water daily. Drinking less than 1 glass of water a day (less than 500 ml) has been associated with higher rates of cancer.

Why Do Healthy People Need Water?

In addition to making up about 60% of the body as a whole, water comprises 65 to 85% of the weight of the heart, liver, and brain, about 60% of muscle mass, and even about 1/3 of the weight of bones. Muscles "bulk up" by combining water and glucose to make glycogen, or by adding water to creatine. Many important nutrients, such as the amino acids and the water-soluble vitamins, have to be absorbed from water solutions.

Most of the contents of the bloodstream are water solutions. Water controls heart rate and blood pressure. It buffers joints from injury, regulates the temperature of the body, forms saliva, and as acts as a shock absorber for the eyes, spinal cord, and brain. Just about the only cells in the body that are not mostly water are fat cells. But do we have to drink tap water, like most Americans, or seltzer water, like most Europeans, to stay hydrated?

Do Coffee, Tea, and Sodas Count as Water?

Many self-described experts try to tell us that caffeinated beverages, sugary beverages, and fruit juices are somehow actually dehydrating. Drinking coffee, we are often told, sucks more fluid out of the system that it puts in. But do we really need 8 glasses of actual water every day?

Heinz Valetin and Sheila Gorman of Dartmouth Medical School believe the answer to this question is "No." Valetin and Gorman point out that the advice has never been that people need 8 glasses, in the American sense of a container holding 300 to 500 ml of water or more, every day. The advice has always been that one needs 8 cups (just 240 ml) of water every day, or the equivalent of about two liters or two quarts of water. And that amount, they believe, is more than research confirms.

Most studies finding benefit from drinking water put the the figure at about 1,300 ml, or about six 240-ml cups, of water every day.

• A study of 48,000 men found that every additional cup of water drunk per day lowered the risk of bladder cancer by 7%, but that the benefits stopped at 1,400 ml (a little over six cups) each day.
• The Adventist Health Study found that drinking 1,185 ml of water per day, a little under six cups, resulted in 40% lower rates of heart disease, compared to drinking just 1 or 2 cups of water per day.
• Studies of colon cancer in men have found greatest benefits from drinking about 5 cups (1,200 ml) of water per day.

Benefits of drinking water are also believed to accrue in chronic fatigue, ADHD, acne, dry cough, dry skin, nosebleed, constipation, bladder infections, and erectile dysfunction. But there are also possible dangers of drinking too much water.

• Drinking too much water can cause a severe dilution of sodium in the bloodstream known as hyponatremia. There can be dizziness, confusion, agitation, headaches, loss of appetite, and in extreme cases, death. The most widely publicized cases of hyponatremia have to do with fraternity pranks forcing the drinking of water until death occurs, extreme thirst after taking the drug Ecstasy (MMDA), and after excessive drinking of beer in a condition called potomania. However, hyponatremia can also occur in hypothyroidism, asthma, pneumonia, cancer, and central nervous system diseases.
• Drinking too much polluted water increases exposure to contaminants.
• Drinking too much water can lead to "accidents" in public when it is not possible to reach a restroom in time.

And there are certain myths about drinking water that just won't go away

1. Myth #1. It is important to drink before one feels thirsty to avoid dehydration. Actually, we usually begin to feel thirsty when we have lost about 2% of our water weight, and the symptoms of dehydration do not occur until we have lost about 3% of our water weight. Of course, drinking before thirst occurs ensures that dehydration will not occur.
2. Myth #2. Dark urine is a sign of dehydration. Actually, dark urine can be a symptom of liver disease or bleeding in the urinary tract.
3. Myth #3. Drinking water keeps the kidneys going. Actually, the kidneys only begin to shut down after about 5% of body weight has been lost to dehydration.
4. Finally, are coffee, tea, and soft drinks useful sources of water? There is no evidence that drinking coffee, tea, and soft drinks causes net dehydration, although some energy drinks increase urination more than the fluid they provide.