The 2009 American Academy of Otolaryngology-Head and Neck Surgery Foundation Annual Meeting & OTO EXPO, held this year in San Diego, was the site of a presentation of research conducted at Brigham and Women’s Hospital in Boston which found a protective effect for the B vitamin folate against the development of hearing loss in older men.*
For their research, Josef Shargorodsky, MD and his colleagues analyzed data from 26,273 male dentists, optometrists, osteopaths, pharmacists, podiatrists, and veterinarians who were 40-75 years of age upon enrollment in the Health Professionals Follow-Up Study in 1986. Health and dietary questionnaires completed every two years were analyzed for the intake levels of several vitamins, including folate. Questionnaires completed in 2004 obtained information on hearing loss diagnosed since the beginning of the study.
Over the course of the follow-up, 3,559 men developed hearing loss. Although no association was noted between the condition and other vitamin intake, men over 60 whose intake of folate from food and supplements was among the highest 20% of participants had a 21% reduction in the risk of developing hearing loss compared with those in the lowest fifth. The intake of alcohol, which can impede the bioavailability of folate, did not impact the relationship observed between folate intake and hearing loss, however, men whose alcohol intake was highest had a reduced risk of hearing loss with greater vitamin B12 intake.
The investigation is the first large epidemiologic study to prospectively examine the relation between diet and hearing loss. “The association between folate intake and incident hearing loss in our cohort is consistent with previous data showing that folic acid supplementation slowed the decline in low frequency hearing in older adults,” the authors write.
“A possible explanation for the impact of age on the relation between folate intake and hearing loss is the increased prevalence of folate malabsorption and folate depletion in the older age group. Higher folic acid intake may be necessary to meet the optimal folate needs in this age group.”
* Otolaryngology—Head and Neck Surgery. 2009 Oct 5;141(3):P95.
According to the most recent statistics available from the US National Poison Data System, there was not even one death caused by a vitamin or dietary mineral in 2007. The 132-page annual report of the American Association of Poison Control Centers published in the journal Clinical Toxicology shows zero deaths from multiple vitamins; zero deaths from any of the B vitamins; zero deaths from vitamins A, C, D, or E; and zero deaths from any other vitamin.*
Furthermore, there were zero deaths in 2007 from any dietary mineral supplement. This means there were no fatalities from calcium, chromium, zinc, colloidal silver, selenium, iron, or multimineral supplements. Sixty-one poison centers provide coast-to-coast data for the US National Poison Data System, which is then reviewed by 29 medical and clinical toxicologists. In 2007, NPDS reported 1,597 fatalities from drugs and other ingested materials. Not one death was due to a vitamin or dietary mineral supplement.
* Clin Toxicol. 2008 Dec;46(10):927-1057.
A report published in the October 11, 2009 issue of the International Journal of Low Radiation added evidence to a protective effect for Ginkgo biloba against radiation damage. Ginkgo biloba is a tree species whose leaves have been used for centuries in Chinese medicine. Ginkgo leaf extract contains antioxidant compounds called ginkgolides and bilobalides which help scavenge free radicals that attack nearly all components of the cell, including DNA.*
In their article, Chang-Mo Kang of the Korea Institute of Radiological and Medical Sciences in Taegu and colleagues describe their use of an assay for radiation-induced programmed cell death (apoptosis) to evaluate the protective effect of ginkgo extract against radiation exposure that occurs during accidents or occupational overexposure. In one experiment, white blood cells from human donors aged 18 to 50 were treated with one of four concentrations of ginkgo extract or a 9% saline solution before being exposed to gamma rays.
The researchers found a significant dose-dependent reduction in apoptotic cells among those treated with ginkgo. While radiation-induced apoptosis occurred in nearly one third of irradiated cells not treated with ginkgo, the number declined to 5% or less in cells treated with the highest concentration of the herb.
In another experiment, mice were treated with ginkgo extract or saline before and after receiving whole body ionizing radiation. Mice that did not undergo radiation served as controls. Examination of the animals’ spleens found that treatment with ginkgo maintained organ size comparable with that of animals that did not receive radiation, while spleens in irradiated animals that did not receive ginkgo were significantly smaller.
In their discussion of the findings, the authors note that cell-damaging free radicals and reactive oxygen species can be generated in excess under numerous conditions, including exposure to environmental chemicals, specific drugs, and during normal aging.
“These results indicate that the radioprotective effects of ginkgo extracts administered prior to radiation are due to the OH radical scavenging activity,” the authors write. “Therefore, ginkgo extract should be useful for the protection of radiosensitive organs against free radicals.”
* Int J Low Rad. 2009 Oct 11;6(3).