Sleep Your Way to a Healthier Weight

January 19, 2005

Studies show that getting more sleep is one of the best ways to fight obesity. One investigation, reported by the National American Association for the Study of Obesity, showed that people who got less than four hours of sleep each night were 73 percent more likely to suffer from obesity than those who get the standard eight hours of rest. Obesity risk was 50 percent higher in people getting about five hours of sleep on average, and 23 percent higher for those hitting the hay for only six hours a night. To make sure the results were valid, the researchers adjusted their findings to account for other contributing factors (like exercise) to isolate the effects of skipped sleep.

Their findings confirmed that the hormones that affect appetites are thrown off by lack of sleep. Leptin, a blood protein that curbs your appetite, decreases and ghrelin, which makes you want to eat, increases when your body is deprived of sleep.

But getting sufficient sleep -- seven to nine hours -- can reset your system in as few as three days.

Vitamin D may slow down prostate tumor growth

A new study suggests that giving vitamin D supplements to men with rising rates of prostate tumor markers (PSA) seems to slow down their rate of tumor growth.

It is a small study and this is very preliminary evidence, but doctors do see a connection between vitamin D levels and PSA levels. "The PSA levels seemed to reflect the seasonal variation in vitamin D levels," Dr. Lawrence Klotz, a urologist at Canada's Sunnybrook and Women's College Health Sciences Center.

Researchers followed 190 men for the study. They found that overall, their PSA levels were flat during the summer, but rose during the fall and winter at the rate of about one percent each month.

The doctors then gave the men 2,000 International Units of vitamin D during the fall and winter months to see what would happen. Interestingly, the vitamin D seemed to cut the rise in PSA rates by more than half. Without vitamin D, PSA rates rose by about five percent. With vitamin D, PSA rates only rose by two percent.

"As far as I know, there is no other nutrient studied that has shown a slowdown in the rate of rise of a PSA." said Reinhold Veith, a professor at the University of Toronto and a leading researcher in the field of vitamin D research.