Green tea compound has antidiabetic effect
The October, 2006 issue of the Journal of Nutrition featured an article by Swiss researchers concerning their finding that epigallocatechin gallate (EGCG), a flavanol in green tea, alleviates diabetes in mice and rats.
In one experiment, type 2 diabetic mice were given diets containing 2.5, 5.0, or 10.0 grams per kilogram of a green tea extract providing over 94 percent EGCG. A control group of diabetic mice received no EGCG, and another group were treated with an antidiabetic drug. Blood glucose was analyzed before treatment and weekly until the study's conclusion at 7 weeks. An oral glucose tolerance test was administered at 5 weeks. At the end of the experiment, blood samples taken from the mice were analyzed for glucose, free fatty acids, triglycerides, and plasma insulin levels.
The researchers conducted a similar experiment with rats who received the EGCG concentrate at 5 grams per kilogram diet for ten weeks while a placebo group received the antidiabetic drug.
EGCG was found to dose-dependently improve glucose levels and glucose tolerance in diabetic mice after 5 weeks. Mice who received the highest dose of EGCG experienced a 36.9 percent average reduction in glucose levels compared to animals who did not receive the compound. Triglyceride levels were also dose-dependently reduced, and plasma insulin was increased. Diabetic rats who received EGCG also experienced improved glucose tolerance and increased plasma insulin, and had lower free fatty acids.
In an additional experiment in which the research team tested the effect of the EGCG concentrate on H411E rat liver tumor cells, the compound was found to downregulate genes involved in lipid metabolism and glucose formation.
"Dietary supplementation with EGCG could potentially contribute to nutritional strategies for the prevention and treatment of type 2 diabetes mellitus," the authors conclude.
Risk of central nervous system tumor lower in children of mothers who used vitamins
A report published in the September, 2006 issue of the journal Cancer Epidemiology Biomarkers and Prevention revealed the finding of research funded by the National Cancer Institute that children of women who take multivitamin supplements early in their pregnancy have a lower risk of developing tumors known as medulloblastoma and primitive neuroectodermal tumors. Medulloblastoma tumors form in an area of the brain called the cerebellum which coordinates movement, and primitive neuroectodermal tumors, which are similar to medulloblastomas, occur in other parts of the central nervous system.
Greta R. Bunin, PhD, of The Children's Hospital of Philadelphia and her colleagues studied 315 children diagnosed with medulloblastoma before the age of six who were registered in the Children's Oncology Group, an organization of pediatric cancer programs in the United States and Canada. The group was compared to 315 randomly selected healthy children. Telephone interviews with the children's mothers were used to obtain information concerning periconception vitamin use.
Dr Bunin's team found that taking multivitamins early in pregnancy was protective against one's children developing the tumors, but taking them later in pregnancy did not appear to be preventive. "Our findings suggest that the time close to conception may be a critical period in the development of these tumors," Dr. Bunin stated. "However, most women do not yet know they are pregnant at this very early stage. That is why women of reproductive age are advised to take multivitamins to prevent neural tube defects even if they are not trying to get pregnant."
Dr Bunin concluded, "Taking multivitamins in the first few weeks of pregnancy definitely helps prevent neural tube defects. While more research remains to be done, our findings suggest that multivitamins may prevent some brain tumors as well."
Curcumin blocks hormone involved in colorectal cancer
In a report that appeared in the September 15, 2006 issue of the journal Clinical Cancer Research, researchers at the University of Texas Medical Branch at Galveston described their finding that curcumin, a compound contained in the spice turmeric, blocks the activity of a gastrointestinal hormone that is involved in the development of colorectal cancer. Curcumin has previously been discovered to help combat a variety of tumor cells, and has been shown to help reduce colon polyps in one small clinical trial.
In research with cell cultures, University of Texas Medical Branch surgery professor B. Mark Evers and his colleagues found that curcumin blocks the activity of a hormone produced in response to the consumption of fat called neurotensin, which they linked to the production of the inflammatory protein interleukin-8. Interleukin-8 increases the growth and spread of human colorectal, pancreatic and other cancer cells. Curcumin acts by reducing biochemical signals within the cell that neurotensin utilizes, thereby lowering the production of interleukin-8.
"We found that in colon cancer cells, neurotensin increases not just the rate of growth but also other critical things, including cell migration and metastasis," Dr Evers noted. "The fact that all that can be turned off by this natural product, curcumin, was really remarkable."
"Our findings suggest that curcumin may be useful for colon cancer treatment, as well as potential colon cancer suppression, in cells that respond to this gastrointestinal hormone, neurotensin," Dr Evers concluded. "About a third of all colorectal cancer cells have the receptor for neurotensin. Thus, the concept would be sort of like what we do for breast and prostate cancer, where the main therapy involves blocking hormones. We hope to do similar things with gastrointestinal cancers that respond to this hormone."
Niacinamide could protect MS patients
The September 20, 2006 issue of the Journal of Neuroscience published the finding of researchers at Children's Hospital Boston that a form of vitamin B3 known as nicotinamide or niacinamide may help protect against nerve damage that occurs in the chronic progressive phase of multiple sclerosis, which is the phase in which most serious disabilities develop and for which there has not yet been found an effective treatment. The vitamin acts as a precursor to nicotinamide adenine dinucelotide (NAD) a compound used by the cells in the production of energy from carbohydrates.
For the current study, research fellow Shinjiro Kaneko, MD and colleagues used mice with experimental autoimmune encephalitis, which is similar to multiple sclerosis in humans. They found that giving daily subcutaneous nicotinamide injections delayed the onset and severity of neurologic disability compared to control animals. Higher doses of the vitamin were associated with a greater benefit.
The treatment protected nerve fibers called axons from inflammation and loss of their myelin covering. The vitamin even helped prevent the further degradation of fibers that had already lost their protective myelin sheath, and was found to be effective when administered after the induction of experimental autoimmune encephalitis, although early administration was more beneficial.
The team discovered that nicotinamide works by increasing NAD in the spinal cord. While mice with the greatest neurologic deficits were found to have the lowest spinal cord levels of NAD, those with the least deficits had the highest levels. Giving NAD directly to the animals also prevented axon degeneration.
"We hope that our work will initiate a clinical trial, and that nicotinamide could be used in real patients," Dr Kaneko stated. "In the early phase of MS, anti-inflammatory drugs may work, but long-term you need to protect against axonal damage."
Cabernet Sauvignon-drinking mice protected from Alzheimer's disease
A report scheduled for publication in the November 2006 issue of The FASEB Journal (Federation of American Societies for Experimental Biology)describes the finding of Dr Giulio Maria Pasinetti and Dr Jun Wang of Mount Sinai School of Medicine in New York that drinking the red wine Cabernet Sauvignon prevented amyloid-beta neuropathology and memory loss in a mouse model of Alzheimer's disease (AD). The results will also be presented in Atlanta next month at the Society for Neuroscience Meeting, which will be held October 14-18.
The researchers used mice bred to develop plaque buildup in the brain resulting from beta-amyloid peptides, which is the primary characteristic of Alzheimer's disease. Beginning at seven months of age, Cabernet Sauvignon or ethanol was added to the animals' drinking water for four months. A control group of mice received drinking water to which neither substance was added.
Animals who received wine-enhanced water were found to have a reduction in the loss of spatial memory function which occurs in Alzheimer's disease as well as reduced amyloid neuropathology compared to mice who received ethanol or plain water. It was discovered that Cabernet Sauvignon promoted nonamyloidogenic processing of amyloid precursor protein, preventing the generation of amyloid.
"Our study is the first to report that moderate consumption of red wine in a form of Cabernet Sauvignon delivered in the drinking water for approximately 7 months significantly reduces AD-type beta-amyloid neuropathology, and memory deterioration in approximately 11-month-old transgenic mice that model AD," Drs Pasinetti and Wang announced. "This study supports epidemiological evidence indicating that moderate wine consumption, within the range recommended by the FDA dietary guidelines of one drink per day for women and two for men, may help reduce the relative risk for AD clinical dementia" they conclude.
Scientists issue call for investment in life span extension
An international meeting of scientists sponsored by the Alliance for Aging Research issued a statement signed on September 12, 2006 which calls on governments and health care organizations worldwide to invest in extending healthy human life to create a "Longevity Dividend" in countries with aging populations. "We have reached a historical moment as scientists learn enough about aging to allow us to postpone a wide range of fatal and disabling diseases expressed throughout the lifespan, the result of which would be health and economic benefits for current and all future generations," they announced.
The statement, entitled "Pursuing the Longevity Dividend," was signed by over 90 scientists and aging research advocates, and affirms that slowing the aging process is scientifically plausible and that increased funding could produce dramatic advances in the field. Dr S. Jay Olshansky of the University of Illinois explained that slowing the rate of aging by as little as seven years would result in lower health care costs, increased savings and greater worker productivity. Dr Olshansky's sentiments were echoed by Nobel laureate Dr Robert Fogel of the University of Chicago and Dr Alexandre Kolache of the World Health Organization, who noted the social and economic benefits to countries with aging populations that would result. The group voiced the need for increased funding for intervention studies in aging because the research has "the potential to do what no surgical procedure, behavior modification or cure for any one major fatal disease can do; namely, extend youthful vigor throughout the lifespan."
"The goal is not to produce a 170-year-old person, but success means it should take 80 years to get to be 60," Alliance director Daniel Perry stated. "We really have no choice but to confront our demographic future head-on with the best ideas science and medical research can discover."
Lutein and zeaxanthin supplementation benefits the skin
The results of a study reported on September 12, 2006 at the Beyond Beauty Paris conference found that compounds in leafy green vegetables known as lutein and zeaxanthin that are commonly ingested as nutritional supplements for eye health also increase hydration, elasticity and surface lipids of the skin while protecting against lipid oxidation.
The current study was conducted by Dr. Pierfrancesco Morganti, who is a professor of applied cosmetic dermatology at the University of Naples in Italy and his colleagues. Women aged 25 to 50 residing in Italy received 10 milligrams oral lutein and zeaxanthin, a 50 part per million topical lutein/zeaxanthin formula, a combination of oral and topical lutein and zeaxanthin, or a placebo for twelve weeks. Dr Morganti found that lutein and zeaxanthin administered orally, topically, and both orally and topically was associated with improvements in skin elasticity, skin hydration, and superficial lipid levels, as well as a reduction in skin lipid oxidation compared to the placebo group. Combined oral and topical lutein provided the greatest overall benefit, resulting in a 60 percent increase in skin hydration, a 20 percent increase in skin elasticity, a 50 percent elevation in superficial lipid levels, and a 65 percent decrease in skin lipid peroxidation.
The study contributes to previous findings which suggest that regular ingestion of lutein may help improve the skin's antioxidant defense system, which helps protect against damage caused by the sun and artificial light.
"This is the first study to determine the impact of lutein/zeaxanthin alone on the human skin," announced Richard L. Roberts, PhD, who is the senior manager of scientific affairs for Kemin Health, the leading manufacturer of lutein. "It provides strong new evidence of lutein's positive role in promoting skin health and appearance by increasing hydration, elasticity and lipid content."
Drinking green tea associated with drop in deaths over a decade
The September 13, 2006 issue of the Journal of the American Medical Association published a report by researchers in Japan that a high intake of green tea was associated with a reduction in mortality from all causes as well as from cardiovascular disease during an 11 year follow-up period.
Shinichi Kuriyama, MD, PhD, of the Tohoku University School of Public Policy, Sendai, Japan, and colleagues examined data obtained in the Ohsaki National Health Insurance Cohort Study of 40,530 Japanese adults, begun in 1994. There were 4,209 deaths from all causes over 11 years of follow up, and 892 cardiovascular disease deaths during 7 years of follow up.
It was discovered that drinking five or more cups per day of green tea was associated with a 16 percent lower risk of dying than the risk experienced by participants who consumed less than one cup per day during the follow-up. When cardiovascular mortality over the seven year period was analyzed, it was found to be 26 percent lower among those who consumed at least five cups of green tea per day. The benefit was even greater among women, who experienced a 31 percent lower risk of dying from cardiovascular disease associated with drinking five cups or more of green tea compared to the group who consumed less than a cup.
Although green tea has shown evidence of reducing such cardiovascular disease risk factors as hypertension and obesity, the current study found a reduction in mortality among green tea drinkers who were lean and among those who did not have a history of high blood pressure. The authors suggest that green tea polyphenols, particularly epigallocatechin-3-gallate, may be responsible for the benefit observed in this study, due to their antioxidant properties.
Cranberry, the natural antibiotic
The annual meeting of the American Chemical Society was the site of a presentation on September 10, 2006 by associate professor of chemical engineering Terri Camesano of Worcester Polytechnic Institute in Massachusetts, concerning the finding that compounds in cranberry juice may not only help prevent urinary tract infections, but could be an alternative to antibiotics for other infections such as tooth decay, gastroenteritis and kidney infections.
By growing the digestive tract bacteria E. coli in various concentrations of cranberry juice or its tannin compounds known as proanthocyanidins, Dr Camesano and her team observed an increasing effect on the bacteria with higher concentrations, which suggests that whole or undiluted cranberry products could have the greatest benefits. By changing the shape of bacteria from rods to spheres, altering their cell membranes, and making it difficult for the bacteria to make contact with cells, E. coli was prevented by cranberry from adhering to cells, which is an initial step in all infections.
In previous research conducted by the team, it was discovered that cranberry juice caused the small tendrils known as fimbriae that exist on the surface of E. coli to become compressed, making it more difficult for the bacteria to bind to the urinary tract lining. The finding of the current research that cranberry altered the rod shape of E. coli has never before been observed. Additionally, gram-negative E. coli began behaving like a gram-positive bacteria, leading the researchers to believe that cranberry juice altered the bacteria's cell membrane--another new finding.
"We are beginning to get a picture of cranberry juice and, in particular, the tannins found in cranberries as potentially potent antibacterial agents," Dr Camesano stated. "These results are surprising and intriguing, particularly given the increasing concern about the growing resistance of certain disease-causing bacteria to antibiotics."
Tocotrienols induce apoptosis in prostate cancer cells
The July 28, 2006 issue of the journal Biochemical and Biophysical Research Communications published the findings of Janmejai K. Srivastava and Sanjay Gupta of Case Western Reserve University in Cleveland, Ohio, that the application of a tocotrienol-rich fraction (TRF) of palm oil resulted in the programmed self-destruction (apoptosis) and growth arrest of prostate cancer cells, while not significantly affecting normal prostate cells. Tocotrienols are four of the eight fractions of vitamin E that may have cancer preventive properties along with other benefits.
The duo used cultures of normal human prostate epithelial cells, virally transformed normal cells, and three types of human prostate cancer cells for the current study. Tocotrienols were administered in concentrations of 5, 10, 20, 40 and 80 micrograms per milliliter. Control groups of cells received an inert solution.
While minimal growth inhibition occurred in the normal and virally transformed normal cells following the addition of the highest concentration of tocotrienols, there was a significant decrease in cell viability and colony formation in all of the prostate cancer cell lines beginning at lower concentrations. Prostate cancer cells treated with tocotrienols underwent significant apoptosis that increased with higher concentrations, while normal cells did not undergo apoptosis. Cell cycle analysis also showed a dose-dependent effect at a particular phase of the cell cycle only in the three prostate cancer lines. "These observations suggest that prostate cancer cells respond differentially to TRF exposure than their normal counterparts," the authors observed.
According to Drs Srivastava and Gupta, the prevalence and long latency period of prostate cancer make it an ideal candidate for chemopreventive measures. To their knowledge this is the first study to demonstrate that tocotrienol-rich fraction of palm oil causes cell cycle arrest and apoptosis in prostate cancer cells while leaving normal cells unaffected.
NCI scientists engineer immune cells to fight melanoma
In what may prove to be a way to treat a variety of cancers, Steven A. Rosenberg, MD and his colleagues at the National Cancer Institute have genetically modified T cells in melanoma patients to recognize and attack their tumors. T cells are a type of white blood cell that combat foreign cells such as those in tumors, yet their ability in most humans is not sufficient to eliminate cancer. The research was published online ahead of print on August 31, 2006 in the Science Express section of the journal Science.
Dr Rosenberg's team removed T cells from 17 people with metastatic melanoma and used a modified virus to insert a receptor that recognizes melanoma cells. After reintroducing the cells into the patients, the researchers found that the cells persisted in the circulation of 15 patients for at least two months, and in two patients after one year. Two of the patients experienced regression of their tumors and were free of disease eighteen months after receiving the therapy.
Although the number of patients in whom the procedure was successful is small, further research is predicted to improve its effectiveness. Dr Rosenberg stated that his team has also found ways to engineer immune cells to attack breast, lung, and liver tumors.
The current research "represents the first time that gene manipulations have been shown to cause tumor regression in humans," Dr Rosenberg stated. "We can take normal lymphocytes from patients and convert them to tumor-reactive cells."
Science's senior editor, Stephen Simpson, commented, "This work marks an important next step in harnessing the power of our immune systems to fight cancer. The publication of this paper should help highlight the significant work to a broad spectrum of people, including patients, clinicians and those involved in basic research."
Drinking juice linked with lower Alzheimer's risk
The September, 2006 issue of The American Journal of Medicine published the finding of Qi Dai, MD, PhD and colleagues that people who drank three or more servings of juice per week had a reduced risk of developing Alzheimer's disease compared to those who consumed juice less than once per week.
Participants were enrolled in the Ni-Hon-Sea Project, which investigated dementia in older individuals of Japanese ethnicity living in Hawaii, Seattle and Japan. The current study involved 1,836 Seattle subjects without dementia who were assessed for cognitive function every two years for up to ten years. Self-administered questionnaires were used to determine fruit and vegetable juice intake.
Adjusted analysis revealed that participants who reported drinking juice at least three times per week had a 76 percent reduction in the risk of developing signs of Alzheimer's disease compared to those who consumed less than one serving per week. The relationship was especially strong among individuals who carried a genetic marker associated with late-onset Alzheimer's disease.
Although the incidence of Alzheimer's disease among Japanese residents is low, the rate is greater among people of Japanese ancestry living in the United States, suggesting that environmental factors such as diet could be involved. The researchers believe that the polyphenol content of juice could be responsible for the benefit observed in the current study. Recent animal studies have associated polyphenol intake with a delay in cognitive decline. "Also, animal studies and cell culture studies confirmed that some polyphenols from juices showed a stronger neuroprotective effect than antioxidant vitamins. So we are now looking at polyphenols," Dr Dai stated.
Future research conducted by Dr Dai will ascertain if high blood concentrations of polyphenols found in fruit and vegetable juices are protective against cognitive decline and Alzheimer's disease.
British journal recommends vitamin D supplements for Asian infants
In response to the re-emergence of vitamin D deficiency in Great Britain, an article published ahead of print in the Archives of Disease in Childhood recommends that vitamin D supplements be given to children of Asian ethnicity from birth to the age of two years. Although vitamin D deficiency had previously declined, the condition has recently become more prevalent due to the cessation of government funding for vitamin D supplementation. Vitamin D is synthesized in the skin when exposed to sunlight, however, increased pigmentation results in less vitamin D synthesis, rendering darker-skinned individuals more susceptible to deficiency.
For the current study, researchers at Burnley General Hospital in Lancashire, England searched for cases of hypocalcemic convulsions, hypocalcemic tetany and rickets in the pediatric records from 1994 to 2005 of a National Health Service trust which served approximately 242,000 residents in northwest England. Combined criteria such as bow legs, tetany, radiological evidence, biochemical results, and other factors were used to diagnosis vitamin D deficiency. Fourteen cases of vitamin D deficiency were identified, twelve of which were diagnosed from 2000 to 2005. All but one of the children were of Asian ethnicity, and none had received vitamin supplements.
The authors determined that vitamin D deficiency was eight times higher among Asian children than among all children studied. One in 117 Asian children were vitamin D deficient compared to 1 out of 923 among all children. Because of the high cost of treating the condition, in addition to the suffering and increased risk of of a number of diseases it confers, the authors "suggest that supplementation with vitamin D of all babies of Asian origin for the first 2 years of life might be the economic answer to a growing problem."