In The News: September 2015

According to a new study published in Cancer Prevention Research, prostate cancer survivors who consume a typical Western diet consisting of red meat, refined grains, processed foods, and high-fat dairy products may be at an increased risk of death from returning prostate cancer, as well as other causes.*

Researchers at Harvard T.H. Chan School of Public Health studied 926 men aged 40 to 84 who were diagnosed with prostate cancer that had not spread. Subjects answered questions about their diets five years after receiving a prostate cancer diagnosis and were monitored for approximately 10 years.

The men diagnosed with nonmetastatic prostate cancer who ate a diet that was more Westernized, were 2.5 times more likely to die of prostate cancer than those who ate the healthiest diet, and 1.5 times more likely to die of any cause.

“Our results suggest that the same dietary recommendations that are made to the general population primarily for the prevention of cardiovascular disease may also decrease the risk of dying from prostate cancer among men initially diagnosed with nonmetastatic disease (cancer that has not spread),” said study leader Dr. Jorge Chavarro.

Editor’s Note: The researchers say men who have been diagnosed with prostate cancer should choose a Mediterranean-style diet rich in fruits, vegetables, and fiber with fewer dairy products and less red meat in order to improve their chances of survival.

A study presented at the International Stroke Conference found that low vitamin D levels are linked to an increased risk of suffering a more severe stroke, as well as poor health in stroke survivors.*

The study included almost 100 stroke patients who were treated at a US hospital between 2013 and 2014. All had experienced an ischemic stroke, which is a stroke caused by blocked blood flow to the brain.

People with low blood levels of vitamin D (less than 30 ng/mL), had about two times larger areas of stroke-related dead brain tissue than those with normal vitamin D levels.

According to author Dr. Nils Henninger, of the University of Massachusetts Medical School in Worcester:

“[This research] provide the impetus for yet other studies to come where you could think of scenarios where you have cases who have a very high risk for developing stroke that you might then select for supplementation.”

Editor’s Note: The researchers also found that those with low vitamin D levels had poorer health in the months following their stroke, regardless of age or initial stroke severity. In fact, for each 10 ng/mL reduction in vitamin D levels, the chance of a healthy recovery in the three months following a stroke fell by almost half.

The results of a trial presented at the 2015 American Society of Clinical Oncology Meeting suggest that the intake of active compounds found in green tea could help protect against the development of prostate cancer among men with premalignant lesions.*

Ninety-seven men with high-grade prostatic intraepithelial neoplasia and/or atypical small acinar proliferation were given capsules containing green tea catechins or a placebo for one year. Among the 49 men who received tea catechins, five developed prostate cancer in comparison with nine among the 48 in the placebo group—a reduction that was considered nonsignificant. When men who had only high-grade prostatic intraepithelial neoplasia upon enrollment were analyzed, a different picture emerged. Of the 26 men in this group who received green tea catechins, the combined rate of the development of prostate cancer or atypical small acinar proliferation was three, compared to 10 of the 25 men who received a placebo.

Editor’s Note: Tea catechin recipients also experienced a reduction in serum prostate specific antigen (PSA, a prostate cancer marker) in comparison with the placebo group.

According to research published in JAMA Ophthalmology, taking metformin was associated with reduced risk of developing the sight-threatening disease open-angle glaucoma in people with diabetes.*

Researcher Julia E. Richards, PhD, director of the glaucoma research center at the University of Michigan in Ann Arbor, and co-authors examined metformin use and the risk of open-angle glaucoma (OAG) using data from a large US managed care network from 2001 through 2010.

Over the course of the study, about 6,000 people (4%) developed glaucoma. Patients over age 65 were three times more likely to be diagnosed with glaucoma than the youngest participants, aged 40 to 45.

After adjusting for age and other variables, the researchers found that people who took the equivalent of more than 1.5 grams of metformin a day for two years were 25% less likely to develop glaucoma.

Every 1 gram increase in metformin was associated with a 0.16% reduction in glaucoma risk, which means that taking a standard dose of 2 grams of metformin per day for two years would result in a 20.8% reduction in risk of glaucoma.

Editor’s Note: “Our hope is that if we can confirm the findings in diabetics, who clearly benefit from metformin for their diabetes, additional studies can be performed among persons without diabetes,” said Dr. Richards.

A review in Patient Safety in Surgery found evidence of a link between insufficient vitamin D levels and adverse outcomes after surgical procedures.*

Researchers Paul Iglar and Kirk Hogan selected 31 studies relating to vitamin D and surgery that included a total of 16,195 subjects for their review. Of these, 26 reported at least one correlation between low perioperative vitamin D and an adverse postoperative outcome.

One study found an 8% higher risk of cancer following kidney transplantation in association with each 1 ng/mL reduction in serum vitamin D. Another investigation uncovered a risk of delayed kidney graft failure that was eight times higher in those with vitamin D deficiency in comparison with nondeficient subjects. And in lung transplant recipients, those who were deficient in the near-transplant period and remained deficient after one year had a rate of dying that was nearly five times higher than recipients who were not deficient in vitamin D.

Editor’s Note: “We contend that learning whether it is safe to deviate far from ancestral levels of vitamin D in patients facing the trauma of surgery, and the demands of healing, is an overarching question, and that until this answer is in hand, measurement and supplementation as indicated is preferred to the no-action approach of the status quo,” the authors write.

The results of a cohort study and updated meta-analyses add evidence to a protective effect for magnesium and potassium against the risk of stroke in women.*

For the prospective cohort study, researchers evaluated data from 86,149 women enrolled in the Nurses’ Health Study I (NHS I) and 94,715 participants in the NHS II. Dietary questionnaires completed by NHS I participants in 1980, 1984, 1986, and every four years thereafter, and in 1991 and every four years thereafter in the NHS II were analyzed for the intake of calcium, magnesium, and potassium from food and supplements. Over 30 years of NHS I follow-up and 22 years of NHS II follow-up, 3,780 strokes occurred.

Among women whose intake of magnesium from food and supplements was among the highest 20% of all participants, the risk of stroke was 13% lower than subjects in the lowest 20%. For potassium, the risk was 11% lower among the top 20%.

Editor’s Note: In updated meta-analyses of the associations of dietary calcium, magnesium, and potassium with stroke risk, the risk of total stroke was determined to decrease by 2% for a 300 mg per day increase in calcium intake, by 13% for a 100 mg per day increase in magnesium, and by 9% for a 1,000 mg per day increase in potassium.

A new study published in the Annals of Internal Medicine evaluated the use of metformin in 17,352 patients aged 19 to 58 years with prediabetes, a health state indicated by abnormally high blood sugar levels. The analysis revealed only 3.7% of these patients were prescribed metformin between 2010 and 2012.*

“Diabetes is prevalent, but prediabetes is even more prevalent and we have evidence-based therapies like metformin that are very safe and that work,” said study lead author Dr. Tannaz Moin. “Metformin is rarely being used for diabetes prevention among people at risk for developing it. This is something that patients and doctors need to be talking about and thinking about.”

Since 2008, the American Diabetes Association has recommended metformin as a measure to prevent diabetes, specifically for those at high risk of the disease. Researchers used a sample size of more than 17,000 participating adults age 19 to 58 with prediabetes. They found that metformin was prescribed for just 7.8% of severely obese patients; with prediabetes, the prevalence of prescriptions for obese individuals was 6.6% versus 3.5% for non-obese people; among people who had prediabetes and two other chronic diseases, 4.2% received prescriptions for metformin, versus 2.8% of people with prediabetes and no other chronic diseases.

Editor’s Note: Metformin prescriptions for women were nearly twice as high (4.8%) compared to men (2.8%).

The results of a review and meta-analysis suggest a protective effect for vitamin D against the risk of developing lung cancer.*

Researchers in Beijing selected nine prospective cohort studies and three nested case-control studies that included a total of 288,778 men and women for their review. Three of the studies examined the association of vitamin D intake with lung cancer and the remainder utilized serum vitamin levels.

Higher vitamin D status, as determined by diet or serum, was associated with a 16% lower risk of lung cancer in comparison with low status. When studies that evaluated serum vitamin D levels were analyzed separately, the risk of lung cancer experienced by subjects whose levels were among the top 20% was 17% lower than those whose levels were among the lowest 20%. For vitamin D intake, the risk was 11% lower among the top one-fifth of subjects.

Editor’s Note: “Current data suggest an inverse association between serum vitamin D and lung cancer risk,” the researchers conclude. “Further studies are needed to investigate the effect of vitamin D intake on lung cancer risk and to evaluate whether vitamin D supplementation can prevent lung cancer.”

A study in Free Radical Biology & Medicine provides an explanation of how vitamin E helps maintain muscle.*

Previous research conducted by Paul McNeil and colleagues demonstrated that vitamin E promoted membrane repair in cultured cells and that oxidants inhibited it. For the current study, rats were given normal rodent chow, chow lacking vitamin E, or deficient chow plus supplemental vitamin E, then were tested in their ability to run downhill on a treadmill. Deficient animals demonstrated reduced running ability compared to normal rats and showed increased muscle cell plasma membrane permeability. Examination of their quadriceps muscle fibers revealed diminished size and greater inflammation.

“Every cell in your body has a plasma membrane, and every membrane can be torn,” Dr. McNeil explained. “Part of how we build muscle is a more natural tearing and repair process—that is the no pain, no gain portion—but if that repair doesn’t occur, what you get is muscle cell death.”

Editor’s Note: Dr. McNeil predicts that vitamin E supplementation will be used not only to improve muscle cell membrane repair in diseases such as muscular dystrophy, but as a protective measure for individuals at risk of injury.

The results of a study of men and women revealed a lower risk of mortality among coffee drinkers over an average of 18.7 years of follow-up in comparison with those who did not consume the beverage.*

The study included 90,914 participants in the Japan Public Health Center-based prospective study who had no history of heart attack, stroke or cancer upon enrollment. Surveys completed at the beginning of the study provided information on coffee intake and other data. The subjects were followed for an average of 18.7 years, during which 12,874 deaths occurred.

In comparison with those who reported almost never drinking coffee, occasional drinkers who consumed less than a cup a day had a 9% lower risk of dying from any cause over follow-up, while those who consumed one to two cups and three to four cups experienced reductions of 15 and 24%, respectively.

Editor’s Note: As possible mechanisms for coffee against cardiovascular disease, authors Eiko Saito of Japan’s National Cancer Center and colleagues observe that the beverage is rich in chlorogenic acid, which slows the rate of glucose absorption and lowers blood pressure. Additionally, caffeine boosts endothelial function by activating nitric oxide synthases and promoting endothelial repair. Coffee also contains pyridinium, which helps prevent excessive blood clotting. In regard to respiratory disease, caffeine is known to act as a bronchodilator, which improves pulmonary function. Furthermore, chlorogenic acid has been associated with a reduction in the risk of mortality due to inflammation.

A study reported on October 15, 2014, in the Journal of Human Nutrition & Food Science concludes an association between higher magnesium intake and improved diabetes outcomes and metabolic syndrome risk.*

Yanni Papanikolaou and colleagues analyzed data from 14,338 men and women aged 20 and older who participated in NHANES from 2001-2010. Estimated average requirement (EAR) values were used to categorize the subjects’ magnesium intake as adequate or inadequate. Participants were assessed for the presence of diabetes or other associated factors.

As magnesium intake increased, insulin, body mass index, waist circumference, and systolic blood pressure fell. Among those having adequate magnesium intake from food combined with supplements, the risk of elevated glycohemoglobin, metabolic syndrome, overweight or obesity, increased waist circumference, elevated systolic blood pressure, reduced high density lipoprotein (HDL) cholesterol, and elevated C-reactive protein were lower in comparison with the inadequate group.

Editor’s Note: “As magnesium has been identified as a shortfall nutrient by the 2010 DGAC report, and Americans continue to struggle with meeting nutrient and food group recommendations, dietary magnesium supplementation coupled with appropriate food choices offer an evidence-based option to meet authoritative recommendations and potentially reduce the risk of diabetes and diabetes-related outcomes,” the authors conclude.