Caffeine has long been
suspect of causing mal-formations in fetus, and that it may reduce fertility rates.
These reports have proved controversial. What is known is that caffeine does
causes malformations in rats, when ingested at rates comparable to 70 cups a day for humans. Many other species respond equally to such large amounts of caffeine.
Data is scant, as experimentation on humans is not feasible. In
any case moderation in caffeine ingestion seems to be a prudent course for pregnant women. Recent references are Pastore and Savitz, Case-control study of caffeinated beverages and preterm delivery. American Journal of
Epidemiology, Jan 1995.
On men, it has been shown that caffeine reduces rates of sperm motility which may account for some findings of reduced fertility.
Caffeine and Osteoporosis (Calcium loss)
From the Journal of AMA: (JAMA, 26 Jan. 1994, p. 280-3.)
"There was a significant association between (drinking more) caffeinated coffee and decreasing bone mineral density at both the hip and the spine, independent of age,
obesity, years since menopause, and the use of tobacco, estrogen, alcohol, thiazides, and calcium supplements [in women]."
Except when:
"Bone density did not vary [...] in women who reported drinking at least one
glass of milk per day during most of their adult lives."
That is, if you drink a glass of milk a day, there is no need to worry about the caffeine related loss of calcium.
Studies on the side-effects of caffeine.
OAKLAND, California (UPI) -- Coffee may be good for life. A major study has found fewer suicides among coffee drinkers than those who abstained from the hot black brew.
The study of
nearly 130,000 Northern California residents and the records of 4,500 who have died looked at the effects of coffee and tea on mortality.
Cardiologist Arthur Klatsky said of the surprising results, ``This is not a fluke finding
because our study was very large, involved a multiracial population, men, women, and examined closely numerous factors related to mortality such as alcohol consumption and smoking.''
The unique survey also found no link between
coffee consumption and death risk. And it confirmed a ``weak'' connection of coffee or tea to heart attack risk -- but not to other cardiovascular conditions such as stroke.
The study was conducted by the health maintenance
organization Kaiser Permanente and was reported Wednesday in the Annals of Epidemiology.
Caffeine and your metabolism.
Caffeine increases the level of circulating fatty acids. This has been
shown to increase the oxidation of these fuels, hence enhancing fat oxidation. Caffeine has been used for years by runners and endurance people to enhance fatty acid metabolism. It's particularly effective in those who are not
habitual users.
Caffeine is not an appetite suppressant. It does affect metabolism, though it is a good question whether its use truly makes any difference during a diet. The questionable rationale for its original inclusion in
diet pills was to make a poor man's amphetamine-like preparation from the non-stimulant sympathomimetic phenylpropanolamine and the stimulant caffeine. (That you end up with something very non-amphetamine like is neither here nor
there.) The combination drugs were called "Dexatrim" or Dexa-whosis (as in Dexedrine) for a reason, namely, to assert its similarity in the minds of prospective buyers. However, caffeine has not been in OTC diet pills for
many years per order of the FDA, which stated that there was no evidence of efficacy for such a combination.
From Goodman and Gilman's The Pharmacological Basis of Therapeutics: