What's Hot Archive
August 22, 2003
Calcium keeps blood pressure normal
The March/April 2003 issue of The Journal of Clinical Hypertension published findings obtained from the third National Health and Nutrition Examination Survey (NHANES III) that increased calcium consumption is associated with a reduction in the age-related increase in systolic blood pressure and pulse pressure. Systolic blood pressure rises with age in most individuals living in industrialized societies, while diastolic pressure tends to decrease after the sixth decade of life.
NHANES III enrolled 39,695 participants from which the researchers selected 17,030 individuals age 20 and older for the current study. Blood pressure and other measurements were obtained for all participants. Dietary information was obtained from a 24 hour recall questionnaire which enabled the researchers to calculate calcium intake as well as other nutrients that could affect blood pressure, such as sodium, potassium and magnesium.
Systolic blood pressure was an average of 5.7 mm HG higher and diastolic blood pressure 3.4 mm HG for every ten years of age, however diastolic blood pressure declines at a rate of 2 mm HG for every ten years of age after the age of 50. High calcium intake, defined as greater than 1200 milligrams per day, was found to be inversely associated with the increase of systolic blood pressure and pulse pressure that occurs with age. Calcium intake was also associated with a reduced increase in diastolic blood pressure up to the age of 50.
The authors predict that "If the calcium intake of the general population were to increase to above 1200 milligrams, the incidence of isolated systolic hypertension in the elderly might be decreased." (Hajjar IM et al, "Dietary calciumlowers the age-related rise in blood pressure in the United States: The NHANES III survey," J Clin Hypertens vol 5 no 2, March/April 2003.)
August 20, 2003
Conventional coronary disease risk factors present in majority of coronary heart disease patients
It had been widely believed that established coronary heart disease risk factors: smoking, diabetes, elevated lipids and hypertension, are present in less than half of the individuals with coronary heart disease. While newly emerging risk factors deserve serious consideration, two studies published in the August 20 2003 issue of the Journal of the American Medical Association (http://jama.ama-assn.org/) sets the record straight with the finding that the vast majority of men and women with the disease have at least one of these four risk factors.
The first, study, led by Philip Greenland, MD, of the Feinberg School of Medicine, Northwestern University, Chicago, analyzed data from three large US studies that included a total of 386,915 participants, with a follow-up period of 21 to 30 years. For subjects who experienced a fatal coronary event, the presence of one of the risk factors ranged from 87 to 100 percent in the three studies. For men aged 40 to 59 years at enrollment who had a nonfatal heart attack, 92 percent had one or more risk factors as did 87 percent of women of the same age group.
In the second study, researchers from the Cleveland Clinic Foundation in Cleveland, Ohio analyzed data for 122,458 patients with heart disease, and found at least one of the conventional risk factors in 84.6 percent of women and 80.6 percent of men.
In an editorial in the same issue of JAMA, John G. Canto, MD, and Ami E Iskandrian, MD, of the University of Alabama at Birmingham, write that the findings "may have enormous public health implications for targeting a large segment of the population at risk of developing CHD" and that the studies "provide evidence that convincingly challenges the frequent claim that 'only 50 percent' of CHD is attributable to the conventional risk factors."
August 18, 2003
Drug that mimics vitamin D boosts prostate cancer treatment
Researchers at Wake Forest University Baptist Medical Center have found that Zemplar, a drug designed to provide the benefits of the active form of vitamin D without the side effects, works synergistically with radiation to destroy cancer cells, thereby lowering the amount of radiation needed. Higher doses of radiation are not desirable because it can affect sexual, urinary and bowel function. The research was published online in the British Journal of Cancer.
Using recently excised prostate tumor cell specimens as well as an established prostate cancer cell line, the researchers, led by Wake Forest University assistant professor of radiation oncolology Constantinos Koumenis PhD, found that Zemplar combined with external beam radiation therapy enabled them to lower the radiation dose by 2.4 times to obtain the same effectiveness as radiation alone. Dr Koumenis explained, "About 30 percent of men with locally advanced prostate cancer fail radiation therapy because the cancerous cells become resistant to treatment. Any agent that increases the cancer cells' sensitivity to radiation, without significantly affecting normal cells, would be of great benefit. The fact that Zemplar is already approved means it could be used in treatment sooner. We've shown that the combination of Zemplar and radiation are synergistic in tumor cells, but much less so in normal cells. This means we could potentially increase the killing of the tumor cells, while minimizing the damage to normal cells."
Previous studies have revealed that Zemplar, given without radiation, reduces the growth of tumor cells.
Koumenis added, "Because cell lines have been studied for so many years, some scientists question whether they truly reflect the biology of prostate tumors. The ability of our collaborative team to isolate 'fresh' tumor cells from patients allowed us to look at both; and we found the same effects in both groups of cells."
August 15, 2003
Nanotechnology triples brain cell lifespan
Research at the University of Central Florida has found that an antioxidant engineered on a microscopic or "nano" scale, when applied to brain cells, increased their lifespan to three to four times that of normal cells. Lead investigator and assistant professor in the Department of Molecular Biology and Microbiology at UCF's Biomolecular Sciences Center, Beverly Rzigalinski, made the discovery by collaborating with Sudipta Seal, an associate engineering professor at the Advanced Materials Processing and Analysis Center.
Nanotechnology involves creating new materials on a molecular scale and will have many applications in all areas of research. Materials can be engineered on a scale that can readily be absorbed by human cells, which could revolutionize medicine in the future.
Dr Rzigalinski applied miniaturized antoixdant particles to rat brain cells and compared them to untreated cells. She stated, "In culture, rat brain cells usually live about three weeks. The cells exposed to the engineered nanoparticles lived three to four times longer."
She also tested the ability of the cells to communicate with one another and found that the treated cells retained their youthful abilities. "This shows there is a potential not just to extend the life span but to preserve function," she added.
Tests show that the nanoparticle antioxidants have an ability to regenerate after entering the cell, allowing them to benefit the cell indefinitely. A regenerative nanoparticle may surpass the limited ability of natural antioxidants, such as many vitamins, to prevent free radical damage and may be helpful in the treatment of age-related disorders like Alzheimer's disease. The particles also have an anti-inflammatory effect.
The National Institute on Aging will be providing Rzigalinski with a $14 million grant to assist her in discovering the reasons for her finding as well as applications for the future.
August 13, 2003
Creatine pumps up mental muscles
Researchers from the University of Sydney and Macquarie University in Australia have found that the popular sports endurance supplement creatine, which is found in muscle tissue, boosts memory and intelligence. The report will be published in the Royal Society Journal Proceedings B.
In a double-blind study, forty-five vegetarian adults received 5 grams creatine per day or a placebo for six weeks, followed by a six week period during which no supplement was given, after which followed another six week period during which each group received the regimen not previously received. Participants completed tests for memory and intelligence at the study's onset, at the end of the first six weeks, and at the end of the final six week treatment period. It was found that creatine supplementation improved brain function, similar to improvements previously discovered for creatine in the heart and other muscle tissue.
Lead researcher Dr. Caroline Rae explained, "The level of creatine supplementation chosen was 5 grams per day as this is a level that has previously been shown to increase brain creatine levels. This level is comparable to that taken to boost sports fitness. Vegetarians or vegans were chosen for the study as carnivores and omnivores obtain a variable level of creatine depending on the amount and type of meat they eat - although to reach the level of supplementation in this experiment would involve eating around 2 kilograms of meat a day!" She added, "The results were clear with both our experimental groups and in both test scenarios: creatine supplementation gave a significant measurable boost to brain power. These findings underline a dynamic and significant role of brain energy capacity in influencing brain performance. Increasing the energy available for computation increases the power of the brain and this is reflected directly in improved general ability."
August 11, 2003
Omega-3 fatty acids alleviate depression
A double-blind study conducted in Taiwan found that administration of omega-3 polyunsaturated fatty acids (omega-3 PUFAs) to a group of depressed individuals provided significant relief compared to those who received a placebo. The report was published in the August 2003 issue of the journal European Neuropsychopharmacology.
Twenty-eight patients ages 18 to 60 diagnosed with major depressive disorder were randomized to receive five capsules per day containing 440 milligrams eicosapentanoic acid and 220 milligrams docosahexanoic acid from fish oil, or a placebo for a period of eight weeks. Prior to the treatment, and at two, four, six and eight weeks, participants rated and were scored on their depressive symptoms. Blood samples were taken before and after the treatment phase.
Following the fourth week of treatment, subjects who were taking the omega-3 supplements showed significant improvement in depressive symptom scores compared to the placebo group. These patients continued to improve through the eighth week of treatment.
The authors provide several possible explanations for omega-3 fatty acids' benefit in depression. One hypothesis is that the fatty acids normalize the altered cell membrane structure and neurotransmission found in depressed patients. Another explanation if that omega 3 fatty acids target parts of the arachidonic acid cascade, which can effect mood. The authors hope that further clinical trials of omega-3 fatty acids in depressed patients will be undertaken, although they observe that there is not much incentive for pharmaceutical companies to do so since the nutrients aren't patentable. However, they urge that "further data collection are crucial for both humanistic and scientific reasons because omega-3 PUFAs are favorable for the safety and lack of teratogenicity (the ability to cause birth defects)." (Su KP et al, "Omega-3 fatty acids in major depressive disorder: A preliminary double-blind, placebo-controlled trial," European Neuropsychopharmacology 13 (2003) 267-271.)
August 8, 2003
High isoflavone and lignan intake associated with lower risk of endometrial cancer
Researchers from the Northern California Cancer Center in Union City, California have discovered an association between the consumption of phytoestrogens and a lower risk of cancer of the endometrium, or lining of the uterus. Endometrial cancer is believed to be caused primarily by exposure to estrogens without cyclic progesterone exposure. Phytoestrogens are naturally occurring hormone-like compounds found in soy and other foods such as coffee and orange juice, which, when consumed, do not elevate the body's own estrogen levels.
Pamela L. Horn-Ross, PhD and colleagues conducted the population based study of non-Asian women aged 35 to 79 residing in the San Francisco bay area. Four hundred eighty-two women diagnosed with endometrial cancer between 1996 and 1999 and 470 age-matched controls were interviewed to provide dietary and other health-related information. Intake of the classes of phytoestrogens known as isoflavones, including genistein and daidzein; coumestans, and lignans was calculated for each participant.
It was found that consumption of isoflavones and lignans was inversely associated with the risk of endometrial cancer, particularly among postmenopausal women. Intake of isoflavones was associated with a greater risk reduction than that of lignans. The class of phytoestrogens known as coumestans did not appear to effect endometrial cancer risk. Postmenopausal women who were obese and who consumed low levels of phytoestrogens had the greatest risk of developing the disease compared with nonobese postmenopausal women whose phytoestrogen consumption was high.
Allaying concerns that consumption of phytoestrogens could promote estrogen-dependent diseases, the authors state that phytoestrogens lower endogenous estrogen levels which inhibits estrogen-dependent cancer growth. In addition, these compounds stimulate the production of sex-hormone binding globulin which results in less free estradiol, and inhibit aromatase, preventing the conversion of androstenedione to the hormone estrone in fatty tissue (estradiol and estrone are estrogens.)
August 6, 2003
Exercise and low fat diet blasts prostate cancer cells
Research published in the August 1 2003 issue of the journal, The Prostate, showed a remarkable effect of diet and exercise on the destruction of prostate cancer cells. The researchers added blood serum from three groups of middle-aged men to cultured human prostate cancer cells and observed the effects. The first group consisted of fourteen men who were overweight and sedentary, and had diets that were high in fat and sugar. The second group of men had been following the Pritikin program (which recommends exercise and a diet that is low in fat, sugar and sodium and high in fiber) for fourteen years. The third group included twelve men who consumed typical American diets but had been part of the University of Nevada Las Vegas Adult Fitness Program for fourteen years.
Serum from both groups of exercisers was found to contain lower levels of insulin-like growth factor 1 (IGF-1) and higher levels of IGF binding protein 1, than that of the nonexercising group of men. Three days after administering the sera to the prostate cancer cell cultures, it was found that the serum of the third group destroyed one quarter of the prostate cancer cells, compared to the destruction of only 3 percent of the cells by serum from the first group. However, followers of the Pritikin program had blood serum that killed half of the prostate cancer cells when added to the culture.
Lead researcher and professor of physiological science at UCLA, James Barnard PhD, stated, "We didn't expect the results would be this dramatic. We don't know yet whether these changes that occurred in a lab setting will also occur in patients, but epidemiological studies suggest they do."
August 4, 2003
Vitamin C protects against ulcer bug
Research published in the August 2003 issue of the Journal of the American College of Nutrition has found a correlation between blood levels of vitamin C and risk of infection with the bacteria H pylori, which is known to cause peptic ulcers and stomach cancer.
The San Francisco Veterans' Administration Medical Center researchers analyzed data and blood samples obtained from the Third National Health and Nutrition Examination Survey, or NHANESII, which was conducted between 1988 and 1994 and included close to 7000 participants. The scientists, led San Francisco VA Medical Center physician Joel A Simon MD, MPH, utilized data collected from 1988 to 1991, during the first phase of the study. Participants ranged in age from two months to ninety years.
Of the 6,746 subjects analyzed in the current study, 32 percent tested positive for H pylori antibodies. Half of these subjects were found to have been infected by a strain of the bacteria that is especially toxic. When vitamin C levels were examined, participants whose levels were highest were found to have the lowest incidence of H pylori infection.
Dr Simon summarized, "This is the largest study to look at the relationship between vitamin C levels and infection by H. pylori . . . . We cannot be certain if the infection lowers blood levels of vitamin C or if higher blood levels protect against infection. However, some studies using animal models suggest that adequate vitamin C intake may reduce infection with these bacteria. The bottom line is that higher levels of vitamin C may have the potential to prevent peptic ulcers and stomach cancer."
August 1, 2003
Prenatal nutrition affects offspring's disease susceptibility
Findings published in the August 2003 issue of the journal Molecular and Cellular Biology revealed a profound effect of prenatal nutrition on mice. Female yellow Agouti mice fed the methyl donor nutrients folic acid, vitamin B12, choline and trimethylglycine (betaine) before and during pregnancy and lactation gave birth to offspring with brown coats, while mice not provided with supplements gave birth to mice with yellow coats. The coat color in this strain of mice changes to brown when expression of the Agouti gene is reduced, yet giving the nutrients to the mice did not changed the gene itself.
The nutrients given to the mice in the study enhance DNA methylation. Methylation of the Agouti gene also reduced the animals' susceptibility to obesity, diabetes and cancer, and could affect other genes.
Senior investigator and professor of radiation oncology at Duke University, Randy Jirtle PhD explained, "We have long known that maternal nutrition profoundly impacts disease susceptibility in their offspring, but w never understood the cause and effect link. For the first time ever, we have shown precisely how nutritional supplementation to the mother can permanently alfter gene expression in her offspring without altering the genes themselves. "
Lead author Rob Waterland PHD added, "The implications for humans are huge because methylation is a common event in the human genome, and it is clearly a malleable effect that is subject to subtle changes in utero . . . Diet, nutritional supplements and other seemingly innocuous compounds can alter the development in utero to such an extent that it changes the offspring's characteristics for life, and potentially that of future generations."
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