The world of nutrition is filled with myths about virtually every type of food and ingredient imaginable. The Internet serves as a major repository of these myths, giving them an apparent credibility that leads people to see unproved misinformation as truth.
Internet brews storm
over caffeine hazards
If you take the time to seriously review the Web information, you'll find many of the same beliefs are repackaged over and over, with each site referring to another and to the same unscientific sources.
One naturally occurring food chemical, 1,3,7-trimethylxanthine, abounds with "black and white" thinking. This chemical exists in products containing guarana, kola nut or mate. It is the reason people buy products such as Surge, Jolt, Mountain Dew, colas, teas, coffee and chocolate. Of course this chemical is caffeine.
Many Web sites paint this chemical compound as a serious threat to human health. One of the evils cited is that caffeine is a diuretic that causes dehydration.
Certainly, proper hydration and water balance are basic to good health. And there is research to show that caffeine stimulates short-term production of urine. However, some health promoters and Web sites have used these facts to draw the seemingly logical conclusion that caffeine-containing beverages should not be counted as sources of water. Some have gone so far as to say that even though coffee is almost all water, it causes dehydration.
Someone finally took a serious look at these assumptions. Dr. Ann Grandjean and her colleagues at the Center for Human Nutrition in Omaha examined whether coffee drinkers are chronically dehydrated and whether the water in coffee is indeed worthless. Just because the caffeine in coffee makes water pass into the urine more quickly, does that mean it leaves you dehydrated?
Their research compared five beverages (caffeinated and non-caffeinated, diet and regular) and evaluated the hydration level of 18 male subjects.
Using various ways to measure hydration, the researchers found that the overall hydration status of the men was the same with all the beverages, caffeinated or not.
Plenty of other undocumented claims about the negative side effects of caffeine can be found. Benign fibrous lumps in the breast were linked to caffeine in the early 1970s, based on anecdotal reports.
However, a National Cancer Institute study involving more than 3,000 women disproved the connection, showing no correlation between caffeine and fibrocystic breast disease.
No scientific evidence indicates that normal caffeine consumption stimulates the development or growth of any type of cancer.
Caffeine has also been blamed for osteoporosis and various heart-disease problems. But again, several studies have shown that caffeine (at two cups consumed per day) is not an important risk factor for osteoporosis and is not related to heart disease, high blood pressure or irregular heartbeat. Even the Surgeon General's report on Nutrition and Health states that caffeine's effect on blood pressure is less than that of climbing stairs or other normal, daily activities.
The bottom line: Drink your coffee black or white, but always take the Web with a big helping of skepticism.
Joannie Dobbs, Ph.D., C.N.S., is a food and nutrition consultant
and owner of Exploring New Concepts, a nutritional consulting firm.
She is also responsible for the nutritional analyses
indicated by an asterisk in this section.
Alan Titchenal, Ph.D., C.N.S., is a sports nutritionist in the
Department of Human Nutrition, Food and Animal Science,
University of Hawaii-Manoa.