Frequent Weight Fluctuations
This nation is obsessed with the subject of peoples weight. Every week we are flooded with newspaper, magazine and television articles reporting the latest news on obesity and its impact on the nations health.
A study completed by the Fred Hutchinson Cancer Research Center in Seattle, Washington reports its findings that women who “yo-yo diet” may be harming their immune system. Alternatively, the study found that women who maintain the same weight over time appear to receive a positive effect on their immune system.
Why is this important? The study found that long-term immune function decreases in proportion to how many times a woman has intentionally lost weight which affects the natural killer cell activity in the womans blood. Natural killer cells are an essential part of the immune system that are responsible for killing viruses and leukemia cells. Low natural killer cell activity has been associated with increased cancer rates. Women who maintained a fairly stable weight over several years had higher levels of such natural killer cells than those whose weight fluctuated frequently.
Women who maintained the same weight for at least five years had a 40 percent greater natural killer cell activity when compared to those who maintained their weight for fewer than two years.
The advice of the researchers who conducted these experiments was simple AVOID FAD DIETS. The findings, while intriguing, were preliminary according to the lead researcher who called for a long-term study to provide more conclusive results. Although the study suggests that yo-yo dieting is harmful, there is clear evidence that weight loss is beneficial for your health. What is of concern is the pattern of weight cycling where women go up and down. Exercise has been shown to boost immunity and temper some of the negative effects of weight loss on the human immune system.
Katherine Tallmadge, a spokeswoman for the American Dietetic Association has been quoted as saying that, “people should avoid popular low carb and low fat diets that can produce initial weight loss but rarely work in the long term”. Study after study shows that moderate restrictions are more likely to offer permanent results which is why registered dietitians are urging people not to do the fad diets, and just try small changes that theyre more likely to be able to live with even if the weight loss is slower.
You may recall that the Fred Hutchinson Cancer Research Center also discovered the fact that women who work the graveyard shift may face an up to 60 percent increased risk of breast cancer.
That study by Dr. Scott Davis was published in the Journal of the National Cancer Institute. The study concluded that sleep interruption, especially among women who work the night shift, is linked to a significant increase in breast-cancer risk. One theory is that nighttime sleep deprivation or exposure to light at night somehow interrupts melatonin production, which in turn stimulates the ovaries to kick out extra estrogen a known hormonal promoter of breast cancer.
For more information on yo-yo weight loss effects or sleep interruption studies should visit the American Dietetic Association website www.eatright.org and the Fred Hutchinson Cancer Center at www.fhcrc.org.