In The News: January 2015

According to an article that appeared in the Journal of Alzheimer’s Disease, a diet enriched with walnuts can help slow down, or even prevent, Alzheimer’s disease.*

Researcher Abha Chauhan, PhD, and associates say an extract in the nuts may provide a protective effect against oxidative damage caused by beta-amyloid protein. A build-up of this protein leads to beta-amyloid plaque, which is believed to play a major role in the development of the disease.

Over a period of nine to 10 months, the team fed 4-month-old Alzheimer’s-induced transgenic mice a diet containing 6 or 9% walnuts, which is the equivalent of 1 or 1.5 ounces of walnuts per day in humans. Control groups consisting of transgenic mice and regular mice were fed a walnut-free diet. Between the ages of 13 and 14 months, all animals were tested for spatial memory and learning ability, position discrimination learning ability, psychomotor coordination, and anxiety-related behavior.

The transgenic mice on a control diet exhibited increased memory deficit and anxiety-related behavior, and impairments in spatial learning ability, position discrimination learning ability and motor coordination in comparison with normal mice on the same diet. The animals that ate the walnuts showed improvements in memory, learning, anxiety and motor development compared to the transgenic controls.

Editor’s Note: In light of the significant amount of inflammation present in Alzheimer’s disease, the researchers suggest the high omega-3 fatty acid content in the nuts could be responsible for the benefits observed.

A study published in the Journal of Clinical Endocrinology & Metabolism found that resveratrol improved spinal bone density in men with metabolic syndrome—a cluster of risk factors associated with an increased risk of cardiovascular disease and diabetes—and may provide potential as a treatment for osteoporosis.*

Sixty-six obese men received 500 mg resveratrol, 75 mg resveratrol, or a placebo twice daily for 16 weeks. Bone mineral density, geometry, and microstructure were assessed before treatment and at the study’s conclusion. Bone alkaline phosphatase and other blood markers of bone formation were measured at baseline and at four, eight, and 16 weeks.

Participants who received the higher dose of resveratrol experienced a 2.6% increase in lumbar spine volumetric bone mineral density at the end of the study and an average 16% increase in bone alkaline phosphatase in comparison with the placebo group at each time point measured.

Editor’s Note : “Our study is the first to reveal resveratrol’s potential as an anti-osteoporosis drug in humans,” announced lead author Marie Juul Ørnstrup, MD, of Aarhus University Hospital in Denmark. “Our findings suggest the compound stimulates bone-forming cells within the body.”

A study published in Proceedings of the National Academy of Sciences found that loss of vision in mice suffering from acute glaucoma, an inflammatory disease, can be caused by high pressure in the eye that sets in motion an inflammatory response leading to death of retinal cells.*

In the study, scientists at UC San Diego School of Medicine and Sun Yat-Sen University in China proved that a large, rapid, and sustained increase in eye pressure switched on a gene (TLR4) that activated a protein called caspase-8. Caspase-8 triggers the production of inflammatory proteins that typically allow mammals to fight microbial infections. By suppressing either the TLR4 gene or caspase-8 protein, the researchers were able to slow retinal cell death in mice with glaucoma.

“This immune response is a double-edge sword because, while these proteins protect us from infection in a normal situation, they stimulate apoptosis (programmed cell death) in retinal cells in cases of acute glaucoma,” said study co-author Dr. Kang Zhang, of UC San Diego School of Medicine.

Editor’s Note: By 2020, an estimated 3 million Americans will be diagnosed with glaucoma, the second leading cause of blindness. The study results will have immediate and broad clinical importance regarding the treatment of the disorder.

The finding of a reduced risk of stroke and premature mortality among women with a higher intake of potassium was reported in the journal Stroke.*

The current investigation utilized data from 90,137 postmenopausal women who had no history of stroke upon enrollment in the Women’s Health Initiative Observational Study. Dietary questionnaire responses were analyzed for potassium intake, which averaged 2,611 mg per day. Over an average 11-year follow-up period, 3,046 strokes (including 2,190 ischemic strokes) occurred and there were 11,596 deaths from all causes.

Among women whose potassium intake was among the highest 25%, there was a 12% lower risk of stroke, a 16% lower risk of ischemic stroke, and a 10% lower risk of dying from any cause over follow-up in comparison with those whose intake was among the lowest 25%.

Editor’s Note: Although the US Department of Agriculture recommends a level of 4,700 mg of potassium daily, lead researcher Dr. Sylvia Wassertheil-Smoller, of the Albert Einstein College of Medicine, New York, observed that, “Only 2.8% of women in our study met or exceeded this level. The World Health Organization’s daily potassium recommendation for women is lower, at 3,510 mg or more. Still, only 16.6% of women we studied met or exceeded that.”

The results of a meta-analysis published in the Journal of Nutrition indicate that supplementing with nutrients could help protect against arterial stiffening that occurs with aging.*

Ammar W. Ashor and colleagues at England’s Newcastle University selected 20 randomized trials that included a total of 1,909 participants aged 22 to 63 for their analysis. Studies involved vitamin C and/or E alone, or a combination of other vitamins and/or mineral supplementation. Arterial stiffness was evaluated via pulse-wave velocity measurement or other methods.

Pooled analysis of the data revealed a significant reduction in arterial stiffness associated with supplementation in comparison with a placebo or no treatment. The benefit was more pronounced in studies in which arterial stiffness was experimentally induced or in primary prevention trials, and was stronger among those with lower plasma vitamin C and E prior to supplementation.

Editor’s Note: “The beneficial effects of vitamins on vascular stiffness may be explained by the reduction of the damaging effects of free radicals on structural and functional components of the vessel walls,” the authors said. “Vitamins inactivate free radicals, reduce inflammation, and therefore protect the integrity of the vascular wall. Furthermore, vitamins increase the bioavailability of the vasodilator and anti-inflammatory molecule nitric oxide.”

The results of a study reported in the International Journal of Cancer suggest a protective effect of higher nutrient levels against the risk of developing cancer of the pancreas.*

The case-control study included participants in the EPIC (European Prospective Investigation into Cancer and Nutrition) study, which was designed to investigate the relationship between diet and other factors with chronic disease incidence. Over 400 subjects diagnosed with pancreatic cancer were matched with an equal number of control subjects who were free of the disease.

For those whose beta carotene levels were among the top 25% of participants, the risk of developing pancreatic cancer was 48% lower than that of subjects whose levels were among the lowest fourth. A 47% lower risk was observed for those who consumed the most zeaxanthin, and for subjects whose alpha-tocopherol levels were among the top fourth, pancreatic cancer risk decreased 38%.

Editor’s Note: Authors Suzanne M. Jeurnink, of University Medical Center Utrecht, and her colleagues note that, “Potential mechanisms of such bioactive compounds include protection against free radical damage to DNA, enhancing immune function, and inhibiting insulin-like growth factor (IGF) by binding to IGF receptors.”

An article published on September 2, 2014, in the journal Antioxidants and Redox Signaling provides evidence that beneficial compounds from broccoli, onions, and other foods could boost cellular defense.*

The current study centers on Nrf2, a protein that enters and exits the cells’ nuclei once every 129 minutes, according to research first conducted by Professor Paul J. Thornalley, of England’s University of Warwick, and associates. When the protein is exposed to health threats, the rate of oscillation and cellular defense increases.

Dr. Thornalley’s team found that sulforaphane, found in broccoli and other cruciferous vegetables, and quercetin, from onions, apples, and other plant foods, increase Nrf2’s speed of oscillation between the cell’s nucleus and cytoplasm to once every 80 minutes.

Editor’s Note : “The way Nrf2 works is very similar to sensors in electronic devices that rely on continual reassessment of their surroundings to provide an appropriate response,” Dr. Thornalley explained. “The health benefit of Nrf2 oscillating at a fast speed is that surveillance of cell health is increased when most needed, that is, when cells are under threat. By understanding how this process works and increasing Nrf2’s speed without putting cells under threat, new strategies for design of healthier foods and improved drugs can be devised.”

Researchers at Detroit’s Henry Ford Hospital report a protective effect of having sufficient vitamin D levels against the risk of dying from sepsis or septic shock within 30 days of intensive care unit admission. The findings were reported in the September 2014 issue of the American Journal of Critical Care.*

The study included 121 men and women admitted to the hospital’s ICU with severe sepsis or septic shock, an inflammatory state resulting from infection in the bloodstream. Blood samples obtained before or during admission were analyzed for serum 25-hydroxyvitamin D levels.

Vitamin D deficiency, categorized in this study as a level of 15 ng/mL or less, was uncovered in 54% of total patients. Thirty-seven percent of vitamin D-deficient subjects died from any cause within 30 days of admission, in comparison to 20% of those who were not deficient.

Editor’s Note : “Mortality may be decreased by ensuring adequate vitamin D concentrations through supplementation with ergocalciferol or cholecalciferol within 30 days of hospitalization,” the authors write. “This finding has important implications because sepsis is a leading cause of mortality in critically ill patients.”

The Journal of Food Science reports the finding of a beneficial effect for resveratrol in preventing the adverse effects of a high-fat diet on mitochondrial function and other factors.*

Researchers divided 24 mice to receive a normal diet, a high-fat diet, or a high-fat diet enhanced with 0.06% resveratrol for 20 weeks. At the end of the experiment, blood and spleen cell samples were analyzed for regulatory T-cell counts and other factors.

While regulatory T-cells in blood and spleen were reduced by the high-fat diet, their survival was improved in animals that received resveratrol. Resveratrol was also associated with a decrease in the elevation of reactive oxygen species production and restoring loss of mitochondrial function that was observed in the regulatory T-cells of high fat diet-fed animals. Resveratrol was found to increase the expression of a regulator of mitochondrial biogenesis and reduce regulatory T- cell apoptosis.

Editor’s Note: “High-fat diet is a significant risk factor for health, and mitochondrial dysfunction is one of the major events activating cell death pathways during high-fat diet-induced oxidative stress,” writes Bin Wang, of China’s School of Food Science and Technology in Jiangsu. “We have already reported that several immune functions were changed in mice by high-fat feeding, indicating that the proinflammatory state of obese individuals might be related to chronic excessive nutrient intake.”

A study published in Circulation affirmed that regular intake of low-dose aspirin may help reduce the incidence of recurrent venous blood clots referred to as venous thromboembolism, as well as the risk of cardiovascular events.*

For the current study, Dr. John Simes, of the University of Sydney, Australia, and fellow researchers analyzed data from the WARFASA (Warfarin and Aspirin) and ASPIRE (Aspirin to Prevent Recurrent Venous Thromboembolism) trials. Participants in both trials received 100 mg aspirin or a placebo daily for a median period of 24.2 months.

Among 1,224 men and women included in the combined analysis, venous thromboembolism occurred in 18.4% who received a placebo and 13.1% assigned to aspirin, resulting in a 32% reduction among aspirin users. Subjects who received aspirin additionally experienced a 34% reduction in the risk of major vascular events, including symptomatic venous thromboembolism, heart attack, stroke, and cardiovascular death, in comparison with the placebo group. The risk of clinically relevant bleeding was not significantly different between the two groups.

Editor’s Note: “The treatment effect of aspirin is less than can be achieved with warfarin or other new generation direct thrombin inhibitors, which can achieve more than an 80% reduction in adverse circulatory and cardiopulmonary events,” Dr. Simes noted. “However, aspirin represents a useful treatment option for patients who are not candidates for anticoagulant drugs because of the expense or the increased risk of bleeding associated with anticoagulants.”

Findings from a study reported in Urologic Oncology indicate that watchful waiting, a no-treatment strategy recommended to many older men with low-grade prostate cancer, may not be appropriate for all patients, particularly African Americans.* “We know that African American men have more aggressive prostate cancer than Caucasian men,” noted lead researcher Kosj Yamoah, MD, PhD.

Dr. Yamoah and associates evaluated data from a group of men with low to intermediate grade cancer as indicated by Gleason scoring of biopsy samples obtained by surgical removal of all or part of the prostate gland. (Restricting the study to men who underwent surgical removal of tissue for biopsy rather than needle biopsy samples helped ensure the accuracy of the tumor grading process by reducing the chance of missed areas of aggressive disease.) Over a seven-year period, disease control was observed in 90% of Caucasian men as opposed to 79% of African American men.

Editor’s Note : “Our study shows that African American men who are diagnosed with a low-grade cancer at first—the cancers that are sometimes watched rather than treated—are more likely to develop aggressive disease sooner than Caucasian men,” Dr. Yamoah concluded.