Anti-oxidant      supplements: Good or bad?

A review of 67 randomised trials of antioxidant supplements has found no evidence that they prolong life, and strong evidence that they might shorten it. The trials included almost a quarter-million participants, including healthy people and those with various diseases.

Overall, the authors of the review paper found, antioxidant supplements had no effect on mortality. But in the strongest studies (19 double-blind trials with good randomisation and follow-up), supplements in doses considerably larger than those in typical multivitamin pills appeared to increase the risk of death, by 16 percent for vitamin A, 7 percent for beta carotene, and 4 percent for vitamin E. It made no difference whether the groups tested were healthy or ill. Vitamin C and selenium, on the other hand, had no discernible effect. The authors state their conclusions firmly. "Beta carotene, vitamin A and vitamin E ," they write, "given singly or combined with other antioxidant supplements significantly increase mortality."

The study, published April 16 in The Cochrane Library, also concludes that more research on vitamin C and selenium is needed. But the authors warn that given the risks of antioxidant supplements in general, such work must be undertaken under the direction of safety committees and with careful independent monitoring of data as it accumulates.  

Put the water bottle down!

Drinking a lot of water is supposed to be healthy, but there is apparently little scientific support for the belief. A review of clinical studies has found no evidence that drinking eight glasses of water a day, the usual recommendation, is beneficial to a healthy person.

Numerous claims have been made about water — that it prevents headaches, removes dangerous "poisons," improves the function of various organs and is associated with reduced risk for various diseases. But none of these is supported by scientific evidence. The authors were not even able to find a study leading to the "eight glasses a day" rule, whose origin remains unknown.

The researchers, in the June issue of The Journal of the American Society of Nephrology, say some studies have found evidence that drinking extra water helps the kidneys clear sodium, and long-term sodium retention might increase the risk of hypertension, but no clinical significance for the phenomenon has been established. Water also helps clear urea, but urea is not a toxin.

There is "intriguing" evidence that water might help decrease appetite and control weight gain, write the authors, who say this might be worth more research.

"Under normal circumstances," said Dr Stanley Goldfarb, a co-author and a professor of medicine at the University of Pennsylvania, "drinking extra water is unnecessary. I want to relieve people of the burden of schlepping water bottles around all day long." 

Depression tied to Alzheimer’s

A history of depression is associated with an increased risk for Alzheimer's disease, a new study has found, especially when the depression develops before age 60.

Researchers began the study with 486 men and women who did not have dementia, following them for an average of six years. A total of 134 reported a history of depression. During the study period 44 developed dementia; of those, 33 developed Alzheimer's. People who had reported incidents of depression before age 60 were almost four times as likely to develop Alzheimer's as those who reported no depressive symptoms. Those who reported depression after 60 were more than twice as likely to develop Alzheimer's as those who did not. "The better we understand the link between depression and Alzheimer's, the more insight we will have into the cause of Alzheimer's," said Dr. Monique M.B. Breteler, the senior author. "This can allow us to develop more rational therapies."

Breteler is a professor of neuroepidemiology at Erasmus Medical Center in Rotterdam, the Netherlands.
The authors acknowledge that they depended on self-reports of depression, and that some people who had suffered mild depression may have been misclassified as having no history of it.

New York Times