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March 2008 vol. 13 no. 3

Education is the best provision for the journey to old age.
Aristotle


Table of Contents:

 

Stress May Increase Risk of Cervical Cancer

A woman’s daily stress can reduce her ability to fight off a common sexually transmitted disease and increase her risk of developing the cancer it can cause, according to a new study. No such association is seen, however, between past major life events, such as divorce or job loss, and the body’s response to the infection.

Human papilloma-virus (HPV) is spread during sexual intercourse. The most common subtype of the virus is HPV16. Infection with HPV16 and other HPV subtypes can cause cervical cancer.

“HPV infection alone is not sufficient to cause cervical cancer,” explained Fox Chase Cancer Center’s Carolyn Y. Fang, Ph.D. “”Most HPV infections in healthy women will disappear spontaneously over time. Only a small percentage will progress to become precancerous cervical lesions or cancer. An effective immune response against HPV can lead to viral clearance and resolution of HPV infection. But some women are less able to mount an effective immune response to HPV.”

Fang and her colleagues hypothesized that stress could lead to alterations in immune functioning that make the body less able to effectively clear the virus. Their study exploring this hypothesis appears in the February issue of Annals of Behavioral Medicine (volume 17, number 1).

In the study, researchers examined potential associations between stress and immune response to HPV among women who had precancerous cervical lesions. The women were asked to complete a questionnaire about their perceived stress in the past month and about major stressful life events that had occurred, such as divorce, death of a close family member or loss of a job.

“We were surprised to discover no significant association between the occurrence of major stressful life events and immune response to HPV16. This could be due to the amount of time that has passed since the event occurred and how individuals assess and cope with the event,” said Fang. “Our findings about subjective daily stress told a different story, however. Women with higher levels of perceived stress were more likely to have an impaired immune response to HPV16. That means women who report feeling more stressed could be at greater risk of developing cervical cancer because their immune system can’t fight off one of the most common viruses that causes it.”


Fight Allergies with Food

Over 50 million Americans suffer from allergies, and certified nutritional therapist Norma Kayte O’Dell says there’s a better way to get relief than by swallowing over-the-counter nostrums and remedies. She recommends changes in diet to strengthen and support the body’s ability to handle typical miseries brought on by allergies. “Foods that help manage inflammation and support the immune system can help alleviate allergic reactions,””she said.

A key food favored by many natural healers is local raw honey. Horticulturist and author of Allergy-Free Gardening Tom Ogren said honey works like allergy shots by helping to build up a tolerance to local pollens. He favors honey produced within ten miles of an allergy sufferer’s home, and said farmer’s markets are the best place to find it.

Ogren also suggests eating berries, saying that they can turn off the allergic response, and also highly recommends garlic and onions, because they contain sulfur and help detoxify the body.

In addition to allergy-fighting foods, O’Dell also advises taking food supplements to help build up the immune system, especially omega-3 fatty acids and vitamins A, E, and D.


Being Over-Weight May Raise Cancer Risk

Being obese or even overweight may increase a person’s risk of developing up to a dozen different types of cancer, European researchers report in a new study.

Doctors have long suspected a link between weight gain and certain cancers, including colon and breast cancers. But the new study, published Friday in the journal Lancet, suggests it could also increase chances for cancer of the esophagus, thyroid, kidney, uterus and gall bladder, among others.

While the study suggests a link, there is no definitive proof that being fat in itself causes cancer.

“To make the link between cause and effect, we need to tick several boxes,” said Dr. Andrew Renehan, the study’s lead author and senior lecturer at the School of Cancer Studies at the University of Manchester. “This study begins to tick the first two or three boxes, but more research is needed to confirm it.”

The researchers compiled data from 141 studies and considered more types of cancers and more diverse populations than had been done previously. The research covered more than 280,000 cases from North America, Europe, Australia and Asia.

The subjects, both overweight and normal weight, were followed for about nine to 15 years, with researchers tracking their body mass index, or BMI a calculation based on weight and height and correlating it with incidents of cancer.

In men, an average weight gain of 33 pounds increased the risk of esophageal cancer by 52 percent, thyroid cancer by 33 percent, and colon and kidney cancers each by 24 percent, the research found.

In women, a weight gain of 29 pounds increased the risk of cancer in the uterus and gall bladder by nearly 60 percent, esophagus by 51 percent and kidney by 34 percent, the study said.

The link was weaker for bone and blood cancers, for both men and women.

In Asian populations, there appeared to be a stronger link between increased BMI and breast cancer, the study said.

“This study provides a lot of circumstantial evidence about the dangers of obesity,” said Dr. David Robbins, a gastroenterologist at Beth Israel Medical Center in New York, who was not involved in the study. “It also highlights the cancer crisis we face as obesity rates increase worldwide.”

Scientists are unsure how being overweight could make people more susceptible to cancer.

“One of the hypotheses is that the presence of excess fat cells could affect the levels of hormones in your body,” Renehan said. “At a cellular level, that may favor the development of tumors in humans.”

Because many studies have found that fatter people are more likely to get cancer, experts often recommend losing weight to reduce cancer risk.

“The simple message is that, if you manage to keep a healthy body weight, you will have a lower risk of developing cancer,” said Ed Yong, of Cancer Research United Kingdom.


Physical Activity May Prevent Prostate Cancer

Men with jobs that require them to be physically active may be getting benefits beyond salary and health insurance - they may be at a decreased risk of developing prostate cancer, according to a study at UCLA’s Jonsson Cancer Center.

Researchers studied more than 2,100 men who worked at the Rocketdyne facility in the San Fernando Valley, many of whom were exposed to radiation and chemicals that may have increased their risk for certain cancers.

The research team identified 362 men who developed prostate cancer and compared them to 1,805 men of similar age and socioeconomic status who did not get prostate cancer.

The study, done in conjunction with researchers at the Olive View-UCLA Education and Research Institute and the University of Michigan, appears in the February issue of the journal Cancer Causes Control.

“The message from this study for today is that if you’re more active, you may be able to prevent this cancer from happening,” said Beate Ritz, a Jonsson Cancer Center researcher, an associate professor of epidemiology in the UCLA School of Public Health and the study’s senior author. “If you have a desk job, do something physically active to counterbalance it.”

The case-control study nested within a larger cohort of more than 10,000 subjects focused on men who worked at the nuclear and rocket engine testing facility from the 1950s to the early 1990s. The cases of prostate cancer were diagnosed between January 1988 and December 1999. Researchers obtained cancer incidence data for the workers from the California Cancer Registry and seven other cancer registries in neighboring states where workers may have moved after retirement.

Data from Rocketdyne company records was used to construct a job exposure matrix that ranked job descriptions by the amount of physical activity required and any harmful exposures the workers might have experienced.

Physical activity was separated into jobs with low, moderate and high amounts of exertion. Men with low physical activity jobs were typically managers, supervisors, analysts, administrators and senior engineers.

Those with moderately physically active jobs included senior mechanics and technicians, inspectors and engineers. Masons and bricklayers, metal fitters, welders, packers, painters, tool and die makers, truck drivers, lift operators and janitors were considered to have highly physically active jobs.

The study found that the men who developed prostate cancer were less likely to hold the more physically active jobs. Those that got cancer also were more likely than the control group to be highly exposed to the chemicals that were evaluated, including hydrazine, benzene, mineral oil, polycyclic aromatic hydrocarbons (PAHs) and trichloroethylene (TCE), which are known or suspected carcinogens.

The findings are supported by other studies that suggest continuous physical activity, but not intermittent activity, is required to lower the risk of prostate cancer. The biologic mechanisms by which physical activity lower prostate cancer risk have not been identified, although some experts have speculated that activity can alter hormone levels in some men.


Measure Body-fat, Not BMI

Measuring body fat, rather than body mass index, appears to more accurately identify people who need lifestyle interventions to lose weight, study findings suggest.

Excess body fat is a risk factor for many major health problems such as heart disease and diabetes, researchers note in the Nutrition Journal.

When evaluating individuals for lifestyle recommendations to minimize such health risks, body mass index (BMI) under identifies risk, said Dr. Ottavia Colombo of the University of Pavia in Italy.

“The use of BMI alone does not discriminate between fat mass and fat-free mass, nor reflect the fat mass distribution,” Colombo told Reuters Health.

Colombo and colleagues recruited 23 men and 40 women, aged 20 to 65 years, to undergo body composition analysis in theHuman Nutrition and Eating Disorders Research Centre at the university. The volunteers were healthy, but led sedentary lives and were not following a low-calorie diet.

The researchers obtained each person’s BMI as well as body-fat measurements including waist circumference and total percent body fat. The also calculated a measurement similar to BMI that identifies fat mass called body fat mass index. The investigators then compared the percentage of the study group that would be told to lose weight according to each calculation.

BMI calculations, they found, identified 11 percent of the group as needing strong recommendations to lose weight and 41 percent as needing basic recommendations to lose weight. By contrast, waist circumference measurements indicated about 25 percent would need strong recommendations to shed pounds and 36 percent would need basic weight loss recommendations, Colombo said.

Moreover, 29 percent and 48 percent would have received similar weight loss recommendations according to total percent body fat measurements, while 21 percent and 54 percent would receive the same, according to body fat mass index.

“Using criteria based on body adiposity (fatness) rather than body weight would result in a much greater proportion of the study population receiving recommendations for weight loss,” Colombo said.

Studies that focus on changes in body fat among larger groups of people recommended for lifestyle change, might better identify which body fat index is most clinically relevant, the investigators say.

SOURCE: Nutrition Journal 2008


Ginkgo Biloba May Protect Memory

Taking the herbal supplement ginkgo biloba may help delay the onset of cognitive impairment in normal elderly adults, according to a study published online Wednesday.

However, the study also showed a higher incidence of strokes and “mini-strokes” in ginkgo users. The reasons for this are unclear and require confirmation in other studies, the investigators say.

Extracts of ginkgo biloba are among the most widely used dietary supplements. The herb is marketed as a memory enhancer, and some studies have suggested it may help improve memory and other mental functions in people with dementia.

“One of the most pressing public health problems facing our society is the rapidly growing number of people who, due to their age alone, are at high risk of developing dementia. The potential to delay or prevent this is of great importance,” study chief Dr. Hiroko H. Dodge, from the Oregon State University in Corvallis, said in a statement.

The three-year study involved 118 people age 85 and older with no memory problems. Half of them took ginkgo biloba extract three times a day and half took a placebo.

During the study, 21 people developed mild memory problems, or questionable dementia: 14 of those took the placebo and 7 of those who took the ginkgo extract. Although there was a trend favoring ginkgo, the difference between those who took ginkgo and those who took placebo was not statistically significant.

However, when the researchers took into account whether people followed directions in taking the study pills, they found that people who reliably took ginkgo had a 68 percent lower risk of developing mild memory problems than those who took the placebo.

“These results need to be clarified with larger studies, but the findings are interesting because ginkgo biloba is already widely used, readily available, and relatively inexpensive,” Dodge said.

As noted, more strokes and mini-strokes were seen in the ginkgo group. Seven people taking ginkgo had strokes, while none of those taking placebo did. “Ginkgo has been reported to cause bleeding-related complications, but the strokes in this case were due to blood clots, not excessive bleeding, and were generally not severe,” Dodge noted in a statement.

“Further studies are needed to determine whether ginkgo biloba has any benefits in preventing cognitive decline and whether it is safe,” he added.


Magnesium Intake May Cut Risk of Gallstones

A diet rich in magnesium appears to reduce the risk developing painful gallstones, according to findings from a US study.

Consumption of magnesium has been declining over the years, due in part to the over-processing of foods, Dr. Chung-Jyi Tsai and associates note in their report in the American Journal of Gastroenterology.

Magnesium deficiency is known to raise triglyceride levels and decrease HDL (“good”) cholesterol levels in the blood, both of which may increase the risk of developing gallstones. Still, the long-term effect of magnesium on the risk of gallstones in humans was not known.

To investigate, Tsai, from the University of Kentucky Medical Center in Lexington, and colleagues analyzed data from 42,705 men, between 40 and 75 years of age, who were enrolled in the Health Professionals Follow-up Study. The men were followed from 1986 to 2002.

The subjects were surveyed every 2 years to assess the occurrence of new illnesses, including gallbladder disease. Magnesium consumption was determined with a semi-quantitative food frequency questionnaire sent to the participants every 4 years.

During follow-up, 2195 men were diagnosed with gallstone disease, the researchers found.

Compared with the lowest level of total magnesium intake, the highest intake reduced the risk of gallstone disease by 33 percent. The same risk reduction was seen when considering just dietary magnesium, when supplements were excluded.

“From many studies by this group and others, it appears that a generally healthy dietary pattern, with more plant-based foods, fiber, and increasing complex carbohydrates, and now increasing magnesium intake will decrease the risk of symptomatic gallstones,” Dr. Cynthia W. Ko, from the University of Washington in Seattle, writes in an accompanying editorial. “This ‘healthy’ dietary pattern will also help in prevention of other chronic diseases in addition to gallstones.””

SOURCE: American Journal of Gastroenterology, February 2008.


Calcium May Not Protect Against Fractures

For years, getting a lot of calcium has been portrayed as one of the best things you could do to prevent osteoporosis and related bone fractures. Small study results supported this view. But when researchers started to crunch the data from large, prospective studies that followed people for many years, the benefits weren’t so clear-cut, reports the March 2008 issue of the Harvard Health Letter.

The ambiguity led to trials to test what effect calcium might have on fracture rates. Two studies showed that calcium didn’t prevent fractures even when taken in combination with vitamin D. Another study showed that postmenopausal women who took a calcium-vitamin D combination were no less likely to break their hip than women who took a placebo pill. And other researchers reported the results from a meta-analysis of studies on calcium that found no connection between high calcium intake and lower hip fracture risk.

While a certain level of calcium intake is undoubtedly important to keeping bones strong, amounts above that level might not do much good, notes the Harvard Health Letter. One reason some of these studies on supplements may not have shown a benefit is because the study participants were already getting over 1,000 milligrams (mg) of calcium daily through diet.

The bottom line: According to current recommendations, Americans over 50 are supposed to get 1,200 mg of calcium daily, but 600 mg is probably enough for most people to keep their fracture risk low. Still, because extra calcium might be protective against colon cancer, a daily intake of 600 to 1,000 mg is a reasonable goal.