Health and Fitness News and Notes

A probiotic supplement could be good for your bones, a new study suggests.

Researchers studied 90 women, 75 to 80 years old, all generally healthy but with low bone mineral density. They measured their bone density at the start of the study, and then randomly assigned them to a placebo or to two daily doses of freeze-dried Lactobacillus reuteri, an intestinal tract microbe that occurs naturally in many, but not all, people.

After one year, they measured the women’s bones again. The reduction in density in the shin bone was nearly half as large in women taking L. reuteri supplements as in those taking the placebo. Side effects, most commonly gastrointestinal symptoms, were similar in the treatment and placebo groups. The study is in the Journal of Internal Medicine.

The lead author, Dr. Anna G. Nilsson, said that why this happens is unclear. “Perhaps estrogens could be affected by probiotics,” she said, “and there is some discussion about calcium absorption, a change in the calcium regulating hormones.”

Nilsson, an associate professor at the University of Gothenburg in Sweden, said that it is not yet time to advise women to take probiotics. “This is the first study in humans,” she said. “We need confirmatory studies. And we’ve only studied one strain of L. reuteri, the type used in animal studies."

Working as a flight attendant may increase the risk for cancer.

Flight attendants are exposed to several factors known to increase cancer risk, including disrupted sleep patterns and exposure to the increased levels of cosmic ionizing radiation at high altitudes.

A new study, in Environmental Health, used health and behavioral data on 5,366 flight attendants, 91 percent currently working and the rest former flight attendants. They had worked for an average of 20 years, and 80 percent were women. The researchers compared their cancer incidence to that of 2,729 people with similar age, income and education who were involved in a separate, larger national health study.

Compared with the controls, flight attendants had increased rates of breast, uterine, cervical, gastrointestinal, skin and thyroid cancers. In women, the rate of breast cancer among flight attendants was 50 percent higher, and the rate of non-melanoma skin cancer was more than four times as high as in the control group.

A co-author, Irina Mordukhovich, who is a research associate at Harvard, said the findings say nothing about passengers’ risks, and in any case an observational study like this cannot establish cause and effect.

Still, she said, “Flight crews have a unique mix of exposures, including disrupted circadian rhythms and exposure to possibly carcinogenic contaminants — insecticides, flame retardants, jet fuel. And ionizing radiation levels, although low, can be cumulative over time."

Drinking coffee is associated with lower mortality rates, and a new study suggests that caffeine is not responsible for the effect.

Researchers had demographic and health data on 498,134 British people, average age 57, including information on coffee consumption and on the genetic variants that affect caffeine metabolism. More than three-quarters were coffee drinkers.

Over 10 years of follow-up, there were 14,255 deaths. They found that the risk of death from any cause, and particularly from cancer and cardiovascular disease, declined steadily as coffee consumption increased. Those who drank a cup a day had a 6 percent lower risk than those who drank less than that, and people who drank eight or more cups a day had a 14 percent lower risk.

The study, in JAMA Internal Medicine, adjusted for age, race, smoking, sex, body mass index, alcohol consumption and other health and behavioral factors.

The associations were similar for ground and instant coffee, and for caffeinated and decaffeinated. Moreover, it made no difference whether people had the genetic variants for slower or faster caffeine metabolism.

Does this observational study mean that everyone should drink more coffee? No, said the lead author, Erikka Loftfield, a research fellow at the National Cancer Institute.

“At this point, the study provides reassurance to coffee drinkers, not guidance. The results don’t indicate that people should begin drinking coffee for its health benefits.”