In The News: November 2011

An article published in the journal Cancer Epidemiology, Biomarkers & Prevention reveals a link between increased use of garlic or grape seed supplements and a lower risk of hematologic malignancies, including Hodgkin and non-Hodgkin lymphomas, and leukemia.*

Researchers examined data from 66,227 men and women enrolled in the VITamins And Lifestyle study. Responses to questionnaires completed between 2000 and 2002 were used to estimate the ten year average daily dose of each supplemental vitamin, mineral or specialty supplement consumed prior to enrollment.

Five hundred eighty-eight hematologic malignancies were identified among the subjects through December 2008. Among those who reported using garlic supplements for at least four days a week over three or more years, there was a 45% lower adjusted risk of a hematologic cancer compared to those who reported no use. For grape seed, the risk was 43% lower in those who reported ever using the supplement compared to nonusers.

Editor’s Note: Daily use of multivitamin supplements for at least eight years was associated with a non-significant 20% lower risk of hematologic malignancies in comparison with no use.

An article published in The Journal of Nutrition, Health & Aging establishes a link between the use of omega-3 fatty acid supplements and a reduced risk of cognitive impairment.*

The current study sought to determine the association of omega-3 from supplements with the development of cognitive decline. Researchers at National University of Singapore analyzed data from 1,475 participants in the Singapore Longitudinal Aging Studies who did not have dementia upon enrollment. Questionnaires administered at the beginning of the study were analyzed for the frequency of omega-3 fatty acid supplement use and for the intake of fish, from which these fatty acids are derived. Cognitive performance was evaluated at enrollment and at a median of 1.5 years later.

Compared to those who did not report daily supplementation, subjects who supplemented had a 63% lower adjusted risk of being diagnosed with cognitive decline over follow-up.

The outcome of a meta-analysis published in the Open Respiratory Medicine Journal concludes that zinc lozenges are beneficial in reducing the length of colds if the mineral is available in sufficient quantities.*

Dr. Harri Hemilä of the University of Helsinki selected thirteen placebo-controlled trials examining the effects of zinc lozenges on cold duration. Three trials tested zinc acetate and five trials tested other forms of zinc in daily doses of greater than 75 milligrams. The remaining five trials evaluated the use of lozenges that contained lower doses of the mineral.

While pooled analysis of the five trials that analyzed the effects of less than 75 milligrams zinc found no benefit, zinc acetate consumed in doses higher than 75 milligrams per day was associated with a 42% reduction in cold duration. Consuming more than 75 milligrams of other forms of zinc was associated with a 20% decrease in the length of colds.

Editor’s Note: Although no long-term adverse effects were observed, high doses of zinc consumed for extended periods of time are not recommended. Nevertheless, Dr. Hemilä remarks that 150 milligrams per day of zinc have been administered for therapeutic uses for months or years in specific patients, and that a trial involving six weeks of supplementation at this level failed to result in a deficiency of copper (a potential side effect of prolonged intake of high amounts of zinc).

An analysis published online in the journal Pharmacological Research reviews the role of antioxidants in the treatment of infertility issues in men and women and concludes that the compounds show significant promise via their effects on vascular function.*

“While the direct effects of antioxidant treatment on the quality of semen and oocytes are still under investigation, a significant body of evidence points to loss of vascular tone as a root-cause of erectile dysfunction and, possibly, alterations to female reproduction,” write authors Francesco Visioli and Tory M. Hagen.

The authors remark that nitric oxide synthesis and bioavailability, which play a major role in vascular function, are impaired by compounds known as free radicals. These damaging molecules can be controlled, in part, by increasing the availability of antioxidants. While commonly supplemented antioxidants, including vitamins C and E, may be helpful, other antioxidants, such as lipoic acid, may have a more profound benefit.

Editor’s Note: Dr. Hagen added that treatment with antioxidants, “Might help prevent other critical health problems as well, at an early stage when nutritional therapies often work best.”

In an article published online in Circulation: Journal of the American Heart Association, Jiang He, MD, PhD, and associates report the outcome of a crossover trial which found that milk and soy protein supplements lower systolic blood pressure among those in the early stages of hypertension.*

A team led by Dr. He divided 352 adults with prehypertension or stage 1 high blood pressure to receive 40 grams of soy or milk protein, or a refined carbohydrate supplement daily for eight weeks, followed by a three week wash-out period in which no supplements were given. The subjects then participated in two additional treatment phases in which they received supplements that had not previously been administered.

The trial revealed a reduction in systolic blood pressure associated with protein, but not carbohydrate, supplementation. “The systolic blood pressure differences we found are small for the individual, but they are important at the population level,” Dr. He stated.

Editor’s note: The authors remark that the study’s findings suggest that partially replacing carbohydrate with soy or milk protein could become part of a nutritional intervention to help prevent or treat high blood pressure.

The outcome of a meta-analysis of 11 trials published in the journal Nutrition uncovered a significant reduction in plasma homocysteine in association with greater intake of omega-3 polyunsaturated fatty acids.*

Researchers in China pooled the results from 702 participants in randomized trials that compared the effects of supplementation with omega-3 fatty acids to a placebo. Treatment periods ranged from 6 to 48 weeks, and doses varied between 0.2 and 6 grams per day.

The analysis confirmed a reduction in plasma homocysteine levels in association with omega-3 fatty acid supplementation, with an average decrease of 1.59 micromoles per liter experienced by those who supplemented compared to those who received a placebo.

“Our systematic review provides, to our knowledge, the most comprehensive assessment to date of the effects of omega-3 polyunsaturated fatty acids on plasma homocysteine,” the authors announce.

Editor’s Note: The authors suggest modulation of gene expression of enzymes involved in the formation and metabolism of plasma homocysteine as a possible mechanism of action for omega-3.

In addition to ensuring optimal intake of vitamins C and D during the upcoming flu season, it may be wise to regularly indulge in a soothing pot of green tea, according to the results of a Japanese study published in the Journal of Nutrition.*

Researchers at the University of Shizuoka conducted surveys of 2,050 pupils during influenza season from 2008 to 2009. The responses provided information concerning the quantity of green tea intake, preventive measures taken against influenza, and the incidence and duration of infections.

Among children who reported drinking tea at least six days per week there was a 40% lower risk of being diagnosed with influenza compared to those who consumed tea fewer than three days per week. Subjects who consumed three to five cups per day had a 46% lower risk of contracting flu in comparison with those who consumed less than one cup daily.

Editor’s Note: “Contrary to the results of green tea consumption, general preventive measures (such as influenza vaccination, hand hygiene, and the use of facemasks) were not associated with the incidence of influenza infection,” the authors remark.

An article published in the journal Critical Care documents the finding of decreased levels of coenzyme Q10 (CoQ10) in patients with septic shock.*

Harvard researchers utilized data from 14 patients with septic shock who participated in a placebo-controlled trial of statin drugs. Blood samples drawn from the septic patients prior to treatment and from 16 healthy controls were analyzed for coenzyme Q10, low-density lipoprotein (LDL), and vascular endothelial and inflammatory markers.

While the control group had a median CoQ10 level of 0.95 micromoles per liter, which is similar to levels previously measured in healthy patients, the median baseline level for those with septic shock was 0.49 micromoles/liter. Higher CoQ10 levels were associated with lower levels of vascular endothelial biomarkers and inflammatory cytokines, although only vascular cell adhesion molecule (VCAM) and interleukin-10 remained lower following the adjusted analysis.

Editor’s Note: Sepsis is an inflammatory state resulting from the spread of infectious agents in the bloodstream. Sepsis and septic shock are major causes of illness and mortality in the US, with over 215,000 deaths occurring each year.

The International Conference on Alzheimer’s Disease was the site of a presentation by Lori Daiello, Pharm.D. of the finding of differences in brain structure between individuals who supplement with fish oil and those who do not.*

The current study included 819 participants in the Alzheimer’s Disease Neuroimaging Initiative, which conducted periodic brain magnetic resonance imaging and memory testing on older adults with normal cognitive function, mild cognitive impairment and Alzheimer’s disease over a three year period. Dr. Daiello and her colleagues compared data obtained from 117 men and women who reported regular fish oil supplement use with data from 702 nonusers.

The team found greater brain volume and better cognitive function over follow-up in fish oil users who did not test positive for the APOE4 gene, which is a risk factor for Alzheimer’s disease. “In other words, fish oil use was associated with less brain shrinkage,” Dr. Daiello stated.

Editor’s Note: Fish oil contains the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have been associated with improved cognitive function.

In the journal Hepatology, Arab researchers report a protective effect for saffron against cancer of the liver in rats.*

Amr Amin and colleagues divided 48 rats into six groups. Liver tumors were induced in four of the groups by the administration of DEN, a potent carcinogen. While one group given DEN received no additional treatment, the three other groups received varying doses of saffron beginning two weeks prior to injection with the carcinogen. Rats that were not treated with DEN were given water or saffron throughout the course of the 20-week study.

Among rats that received the carcinogen, fewer of the saffron-treated animals had liver masses at the end of the treatment period in comparison with rats that were not pretreated, and the number of nodules detected was lower. No nodules were found in the rats that received the highest dose of saffron.

Editor’s Note: In separate experiments in cultured liver cancer cells, the administration of saffron was shown to arrest growth and increase programmed cell death.

In an article published in the journal Stroke, researchers at Université Laval Quebec report that the administration of the omega-3 fatty acid docosahexaenoic acid (DHA), which occurs in fish oil, reduces damage caused by stroke in an animal model.*

The team gave male mice a diet supplemented with DHA, a diet deficient in omega-3 fatty acids, or a control diet for three months. Stroke was induced by middle cerebral artery occlusion, and the size of the damaged areas was assessed. Blood samples were analyzed for markers of inflammation and other factors.

Mice that were treated with DHA had areas of ischemic damage that were 25% smaller and higher levels of a molecule that prevents programmed cell death compared with the other groups. The DHA-treated animals also had lower levels of the inflammatory markers COX-2 and interleukin-1, as well as a higher ratio of omega-3 to omega-6 fatty acid levels.

Editor’s Note: Co-author Frédéric Calon observed that “Since DHA is readily available, inexpensive, and reduces the risk of a number of health problems without causing significant side effects, the risk:benefit ratio tends to favor the regular consumption of fish or DHA.”