In The News: August 2012

An article published recently in Stroke reports a protective effect for greater vitamin D intake against the risk of ischemic stroke in Japanese-American men.*

Gotaro Kojima, MD, and colleagues utilized data obtained from 7,385 Japanese-American men who were between the ages of 45 to 68 upon enrolling in the Honolulu Heart Program. Dietary interviews conducted upon enrollment were analyzed for the intake of vitamin D from food.

Over the 34-year follow-up period, stroke was documented in 960 subjects. For men whose vitamin D intake was among the lowest 25% of participants, the risk of stroke was 22% higher compared to the risk experienced by those whose intake was among the top 25%. When stroke was analyzed by type, the risk of thromboembolic stroke was 27% higher for those whose vitamin D intake was lowest in comparison with the highest group.

Editor's Note: "Based on the results of this and other epidemiological studies, higher vitamin D intake or vitamin D supplementation may be beneficial for stroke prevention," the authors write.

Curcumin To Be Tried In Colon Cancer Patients

An upcoming trial conducted by the Cancer Research UK and National Institute for Health Research Experimental Cancer Medicine Centre (ECMC) in Leicester, England, will evaluate the effectiveness of curcumin, a compound that occurs in turmeric, as a means of improving the effectiveness of standard chemotherapy for metastatic colon cancer.*

In previous experiments, curcumin was shown to enhance chemotherapy’s ability to kill cultured colon cancer cells. Colorectal cancer patients are commonly treated with a combination of three chemotherapy drugs, yet approximately half of those treated fail to respond and those who do respond are frequently plagued with side effects such as severe nerve pain.

The trial will recruit 40 patients with colon cancer that has metastasized to the liver. Three-fourths of the participants will be administered curcumin supplements for one week prior to being treated with standard chemotherapy drugs, while the remainder will receive chemotherapy alone, and the benefits and side effects of treatment will be evaluated.

Editor's Note: "The prospect that curcumin might increase the sensitivity of cancer cells to chemotherapy is exciting because it could mean giving lower doses, so patients have fewer side effects and can keep having treatment for longer," commented chief investigator William Steward, who is the ECMC director at the University of Leicester.

In a recent article in the Journal of Nutritional Biochemistry, researchers from Oregon State University reported a benefit for curcumin, a compound found in the spice turmeric, in innate immune function.*

Adrian Gombart and colleagues discovered that curcumin nearly tripled the expression of a gene that encodes a protein known as cathelicidin antimicrobial peptide (CAMP), which can help combat bacteria, viruses, and fungi that have not been previously encountered by the immune system. CAMP is the only known antimicrobial peptide of its kind in humans, and is able to destroy a wide range of bacteria (including that which causes tuberculosis) as well as help prevent sepsis. While curcumin's effect on CAMP is not as potent as that previously found for vitamin D, the compound may still be of value in improving immune function, in addition to providing anti-inflammatory and antioxidant benefits.

Editor's Note: Dr. Gombart remarked that although curcumin is generally consumed in low levels, "It's possible that sustained consumption over time may be healthy and help protect against infection, especially in the stomach and intestinal tract."

A review and meta-analysis reported in the Journal of the American Medical Association found a protective effect for orally-administered probiotics against diarrhea that often develops as a response to antibiotic drugs.*

Susanne Hempel, PhD, and her colleagues reviewed 82 randomized clinical trials of patients receiving antibiotics that compared the effects of a probiotic to no treatment, a placebo, or a different probiotic or probiotic dose. A pooled analysis of 63 of the trials, which included a total of 11,811 participants, concluded that the use of probiotics was associated with a 42% lower risk of developing diarrhea as a result of antibiotic use compared to not consuming probiotics.

"The pooled evidence suggests that probiotics are associated with a reduction in antibiotic-associated diarrhea," the authors conclude. "More research is needed to determine which probiotics are associated with the greatest efficacy and for which patients receiving which specific antibiotics."

Editor's Note: While antibiotics destroy harmful as well as beneficial bacteria, probiotics consist of beneficial live microorganisms whose presence in the digestive tract can help prevent the overgrowth of unhealthy organisms.

An article published in the Annals of Neurology reports a protective effect for diets containing high amounts of blueberries and strawberries against cognitive decline in older women.*

Dr. Elizabeth Devore of Harvard Medical School and her associates evaluated data from women who were enrolled in the Nurses' Health Study in 1976. Questionnaires completed every four years since 1980 were analyzed for the frequency of berry intake as well as the intake of 31 individual flavonoids. Cognitive function was tested every two years in 16,010 participants who were over the age of 70 between 1995 and 2001.

Consuming a high amount of blueberries or strawberries was associated with a slower decline in cognitive function test scores over the follow-up period compared to women whose intake was lower, resulting in a delay in cognitive aging of up to 2.5 years.

Editor's Note: Berries are high in compounds known as flavonoids, which may help reduce the negative impact of inflammation and stress on cognitive function. In this study, greater intake of the anthocyanidin class of flavonoids and total flavonoids was also associated with a reduced rate of cognitive decline.

The results of a trial published in The American Journal of Cardiology reveal a benefit for resveratrol in reducing cardiovascular disease risk factors in men and women taking statin drugs.*

Spanish researchers divided 75 participants who were at high risk of cardiovascular disease to receive a grape extract containing 8 mg resveratrol, a grape supplement without resveratrol or a placebo daily for six months, followed by a six month period during which the dose of the treatments was doubled. The pro-inflammatory cytokine interleukin-6 increased and the anti-inflammatory molecule interleukin-10 decreased by the end of the study in the placebo group, but no changes were observed among those who received grape extract without resveratrol. Subjects who received resveratrol experienced a 26% decrease in C-reactive protein as well as a 19.8% decline in TNF-a by the end of twelve months, indicating a significant decrease in inflammation.

Editor's Note: Additionally, plasminogen activator inhibitor type 1 (PAI-1) was reduced, reflecting a reduction in the risk of excessive blood clotting, while adiponectin and interleukin 10 were increased in the group that received grape extract with resveratrol.

A recent study performed at the University of Missouri showed that apigenin, a natural substance found in celery and parsley, may be a non-toxic treatment for an aggressive form of human breast cancer.* According to Salman Hyder, the Zalk Endowed Professor in Tumor Angiogenesis and professor of biomedical sciences in the College of Veterinary Medicine and the Dalton Cardiovascular Research Center, apigenin slowed the progression of human breast cancer cells in three ways: By inducing cell death, by inhibiting cell proliferation, and by reducing expression of a gene associated with cancer growth. Blood vessels responsible for feeding cancer cells also had smaller diameters in apigenin-treated mice compared to untreated mice. Smaller vessels mean restricted nutrient flow to the tumors and may have served to starve the cancer as well as limiting its ability to spread.

"This is the first study to show that apigenin, which can be extracted from celery, parsley, and many other natural sources, is effective against human breast cancer cells that had been influenced by a certain chemical used in hormone replacement therapy," Hyder concluded.

Researchers with Bayer Pharma AG, of Berlin, Germany reported in a new study that testosterone replacement may promote weight loss in obese older men who have low levels of the hormone.* The purpose of the study was to discover improved ways that obese men could lose weight.

Traditionally, reducing caloric intake does result in a reduction of overall weight, however, lean body mass is reduced as well. The researchers acknowledged that adding a moderate exercise program to a diet that limits food intake can maintain lean body mass and improve insulin sensitivity in obese men, but in the long run, sticking to these measures is difficult for most men. While surgery may be an option for some men, a few clinical and pre-clinical studies have pointed to a role for testosterone to combat obesity.

The researchers found that overall, lower levels of testosterone increase the accumulation of fat deposits around the mid- section. This layer of fat is commonly related to increased risk for metabolic syndrome, type 2 diabetes mellitus, and cardiovascular disease.

Taking this into account, the researchers concluded that testosterone treatment in obese men may increase energy, mood, and reduce fatigue, which could allow these men a greater chance at success in terms of committing to an exercise program and maintaining a reduction in daily calorie consumption.