Calcium Supplements Protect Bones in Elderly

Calcium supplements reduce the risk of fractures in elderly patients, according to a new metaanalysis. Photo by Brand X Pictures.

Source: BM Tang et al., "Use of Calcium or Calcium in Combination with Vitamin D Supplementation to Prevent Fractures and Bone Loss in People Aged 50 Years and Older: A Meta-Analysis," the Lancet, vol. 370, no. 9588 (August 25, 2007): 657–666.

Calcium supplements may lower the risk of fractures in people over the age of 50 by more than 10%, according to a new metaanalysis published in the August 25, 2007, issue of the Lancet.

After combining data from 17 studies involving 52,625 people at least 50 years old, researchers from the University of Western Sydney in Australia found that supplementation was linked to a 12% reduction in risk of fractures and a 0.54% and 1.19% lower risk of bone loss at the hip and spine, respectively. Moreover, the researchers uncovered better results when the supplements contained at least 1200 mg of calcium or at least 800 IU of vitamin D.

"Our metaanalysis has shown that calcium supplementation, alone or in combination with vitamin D supplementation, is effective in the preventive treatment of osteoporotic fracture," according to the researchers, who added that poor compliance is "a major obstacle" to obtaining calcium's full benefits.

Dosage May Be Key to Vitamin E Efficacy

Source: LJ Roberts et al., "The Relationship between Dose of Vitamin E and Suppression of Oxidative Stress in Humans," Free Radical Biology and Medicine [published online July 4, 2007].

Several clinical studies have failed to demonstrate that vitamin E prevents heart attacks. But the studies may have been poorly designed and used vitamin E dosages that were too low to produce a beneficial effect, according to new research published online in the journal Free Radical Biology and Medicine.

In the study, researchers from Vanderbilt University Medical Center (Nashville, TN) discovered that it took 16 weeks for a 3200-IU-per-day dose of vitamin E to suppress the formation of F2-isoprostanes, markers for oxidative stress, in people at risk for cardiovascular disease (CVD). They noted that the dosage was more than 100 times the recommended daily intake and approximately four times higher than the dosage used in previous clinical studies involving vitamin E.

In another study involving people at risk for CVD, the researchers administered vitamin E doses ranging from 0 to 3200 IU per day over a period of 16 weeks, determining that at least 1600 IU per day are necessary to reduce oxidative stress.

"It was clear that large doses—and doses in excess of what all clinical studies had used—were necessary," according to Jason Morrow, MD, chief of Vanderbilt's division of clinical pharmacology. The researchers also noted that even with high doses of vitamin E, the reduction of F2-isoprostanes only reached 50%, suggesting that vitamin E may not be a very effective antioxidant.

According to study coauthor and Vanderbilt professor of medicine Jack Roberts, MD, "vitamin E is not the spiffy antioxidant everybody thinks it is."

Pectin Could Be Lethal to Prostate Cancer Cells

Pectin, a fiber derived from apples and other fruits, may induce programmed cell death in prostate cancer cells. Photo by Brand X Pictures.

Source: CL Jackson et al., "Pectin Induces Apoptosis in Human Prostate Cancer Cells: Correlation of Apoptotic Function with Pectin Structure," Glycobiology, vol. 17, no. 8 (August 2007): 805–819.

A fiber derived from fruits and vegetables killed prostate cancer cells in an in vitro experiment, report researchers from the University of Georgia at Athens Cancer Center.

In the experiment, researchers tested the effects of several types of pectin, including fractionated pectin powder (FPP), citrus pectin, and pH-modified citrus pectin on androgen-responsive and androgen-independent prostate cancer cell lines. While FPP induced a 40-fold increase in apoptosis compared with untreated cells, citrus pectin did not appear to have an effect until it underwent heat treatment. The researchers also found that base conditions weakened FPP's effects.

"What this paper shows is that if you take human prostate cancer cells and add pectin, you can induce programmed cell death," according to associate professor Debra Mohnen, PhD. "If you do the same with noncancerous cells, cell death doesn't occur."