What's Hot Archive
June 29, 2005
B vitamin supplementation reduces atherosclerosis
In the July 2005 issue of the journal Atherosclerosis (http://www.sciencedirect.com/science/journal/00219150), German researchers reported that a combination of folic acid, vitamin B6 and vitamin B12 reduced intima-media thickness (IMT) of the carotid artery in men and women at risk of cerebral ischemia. Measurement of carotid artery intima-media thickness is used to determine the presence and extent of atherosclerosis. Thickening of these layers of the artery is associated with a greater extent of the disease.
Uwe Till and colleagues enrolled fifty patients with intima-media thickness greater than or equal to 1 millimeter in the double blind, randomized trial. Twenty-six participants received 2.5 milligrams folic acid, 25 milligrams vitamin B6 and 500 micrograms vitamin B12, and 24 received a placebo daily for one year. Intima-media thickness was evaluated by ultrasound, and blood samples evaluated for homocysteine (Hcy) and other factors at the study's onset and conclusion. Sixty percent of the participants were determined to have elevated homocysteine, defined by values greater than 10 micromoles per liter of plasma.
At the end of the study, plasma homocysteine was reduced below 10 micromoles per liter in all subjects who received the vitamins, while it remained basically unchanged in the placebo group. Carotid artery intima-media thickness significantly decreased in those who received the vitamin treatment, compared to a slight increase in those who received the placebo. Analysis of the results did not find a strong causal relationship between the changes in homocysteine and intima-media thickness, suggesting that the benefits observed in the arteries were a direct effect of the vitamins.
The authors write, "To our knowledge, the data presented in this report give the first placebo-controlled evidence that vitamin supplementation can reduce carotid IMT in patients at cardiovascular risk and with an age-corresponding plasma HCy concentration."
June 27, 2005
Vitamin D and calcium lower diabetes risk
A study reported at the 65th Annual Scientific Sessions of the American Diabetes Association held in San Diego, California, found a reduced risk of developing type 2 diabetes in women who had greater intakes of calcium and vitamin D. Anastassios G. Pittas of Tufts-New England Medical Center in Boston and colleagues evaluated dietary information from 81,680 participants in the Nurses' Health Study who did not have diabetes, heart disease, or a history of stroke or cancer in 1980. The women were followed until 2000, during which time food frequency questionaires were administered every two years. Intake of calcium and vitamin D from food was added to that from multivitamins and calcium and vitamin D supplements to calculate the total intake.
At the end of the follow up period, 4,233 (5.2 percent) of the women had developed type 2 diabetes. Dr Pittas reported that a high intake of either calcium or vitamin was associated with a reduction in the risk of diabetes, but high intakes of both conferred an even greater benefit. After adjustment for age, body mass index, family history of diabetes, and other factors, the relative risk of developing type 2 diabetes was 28 percent lower in women whose consumption of vitamin D from all sources was in the top one-fifth of all participants compared to the those whose intake placed them in the lowest fifth. This association remained after adjusting for type of fat and fiber consumed, and glycemic load.
Dr Pittas concluded, "If these results are confirmed by other studies, they will have improtant public health implications as both of these interventions can be implemented easily and inexpensively to prevent type 2 diabetes."
June 24, 2005
Review cites evidence for chronic inflammation in development of prostate cancer
A review published in the July 2005 issue of Carcinogenesis (http://carcin.oxfordjournals.org/) explored the mechanisms by which chronic inflammation of the prostate could lead to the development of cancer.
Researchers from Johns Hopkins University introduced their topic by observing that chronic inflammation resulting from infection or an environmental exposure has been implicated in a variety of cancers. Inflammation is believed to initiate cancer by damaging the cells and their genetic material, promoting cellular replacement, and creating a microenvironment that contains an abundance of cytokines and growth factors that promote cell replication, angiogenesis and tissue repair. Several studies have linked a diagnosis of prostatitis (inflammation of the prostate gland) with a greater risk of the subsequent development of prostate cancer. A meta-analysis published in the journal Epidemiology in 2002 found that increased sexual activity and sexual partners, and having had any sexually transmitted infection all increased the relative risk of developing the disease. Other studies have determined associations between prostate cancer and two types of serum antibodies against human papilloma virus (HPV)--the same antibodies which are associated with a high risk of cervical cancer in women.
Unlike some cancers such as colon cancer, prostate cancer patients have a significant amount of diversity in genetic patterns associated with the disease. Alterations have been observed in several genes involved in inflammatory damage defense and tissue recovery.
A pathological finding in the prostate glands of older men is focal prostatic epithelial atrophy, which is associated with acute or chronic inflammation. The authors hypothesize that these regions could develop into prostate intraepithelial neoplasia or prostate cancer.
The authors hope that further insight into the relationship between inflammation and prostate cancer could reveal new targets for prevention and treatment.
June 22, 2005
Omega-3 fatty acids protect bypass patients
A report published in the May 17 2005 issue of the Journal of the American College of Cardiology (http://www.sciencedirect.com/science/journal/07351097) summarized the findings of Italian researchers that giving omega-3 fatty acids to patients before and after coronary artery bypass graft surgery helps protect them from atrial fibrillation, a type of heart arrhythmia that is often associated with the procedure.
Seventy-nine men and women scheduled for coronary artery bypass graft surgery received 2 grams per day omega-3 polyunsaturated fatty acids consisting of EPA and DHA for at least 5 days prior to surgery and following the surgery until the day of discharge. A control group of 81 patients received the usual care minus supplementation. Heart rhythm monitoring was continuously performed for four to five days following the operation, and electrocardiographic data were reviewed by cardiologists for abnormal rhythms. During the patients' remaining hospitalization, electrocardiograms were administered daily.
Atrial fibrillation was observed in 33.3 percent of the control group compared to 15.2 percent of the group who received omega-3 fatty acids. Although mortality was similar between the groups, those who received the supplements spent fewer days in the hospital after their surgery.
The authors determined a 54.4 percent relative risk reduction for atrial fibrillation was experienced by those in the study who received omega-3 fatty acids, demonstrating a significant protective effect for EPA and DHA. The compounds may provide their benefits through antiarrhythmic or antiinflammatory effects. In conclusion, they write, "This is the first direct evidence of an atrial antiarrhythmic effect of PUFAs and may pave the way to other studies aimed at defining any possible atrial antifibrillatory effect of PUFAs in other clinical conditions."
June 17, 2005
New blood vessels from old cells
A research letter published in the June 18 2005 issue of The Lancet (http://www.thelancet.com/) summarized the findings of scientists from Duke University's Medical Center and Pratt School of Engineering that cells taken from older individuals with cardiovascular disease can be used to grow new blood vessels. Older patients are often in need of arterial bypass surgery, but do not have suitable blood vessels of their own available for grafting. Prosthetic vessels can be used when larger vessels are needed, but the smaller polymer vessels often become clogged with blood clots.
Associate professor of anesthesiology and of biomedical engineering, Laura Niklason, MD, PhD and colleagues took cells from the saphenous vein in the lower legs of four men between the ages of 47 and 74 who underwent bypass surgery. A tube made of a spongy biodegradable polymer was impregnated with the cells, and a vitamin and other nutrient solution was pulsed through the tube. Following the proliferation of the smooth muscle cells, endothelial cells, which line the arteries, were added. The process took up to seven weeks.
Although the vessels made in this experiment were not strong enough to be implanted, Dr Niklason stated that they can be strengthened by adding different factors to the nutrient solution, or by genetically manipulating the cells to manufacture more collagen. The researchers believe that the technique could be clinically applicable within five to ten years.
Dr Niklason commented, "There is a great need for viable alternatives to our current available options for treating patients with coronary artery or peripheral arterial disease . . . The ability to grow new vessels from older cells represents a crucial initial step towards growing blood vessels from a patient's own cells that can be used to treat that patient's vascular disease. "
June 15, 2005
Reduced prostate cancer incidence correlated with greater sunlight exposure; vitamin D believed to be mechanism
A study published in the June 15 2005 issue of the journal Cancer Research (http://cancerres.aacrjournals.org/) reported that increased exposure to sunlight equalled a decreased risk of developing prostate cancer. Vitamin D produced in the skin as the result of sun exposure is believed to be the mechanism behind this finding. Previous research by coauthor Gary G Schwartz, PhD of Wake Forest University discovered that the prostate gland uses vitamin D to promote the normal growth of prostate cells and to prevent the spread of prostate cancer.
In the largest study of its kind so far, researchers from the Northern California Cancer Center, the Keck School of Medicine of the University of Southern California, and the Comprehensive Cancer Center of Wake Forest University compared 450 Caucasian men with advanced prostate cancer to 455 men without the disease. Sun exposure was measured by comparing the skin under the arm, which is protected from sun exposure, to the skin on the forehead. In addition, lifetime sun exposure history was obtained from the participants.
While underarm sun exposure was equal in both groups, men who did not have prostate cancer had significantly darker forehead pigmentation than underarm skin compared to the group with cancer, demonstrating an association between sun exposure and decreased prostate cancer risk. This risk was further reduced in men with specific gene variants.
The authors stress that men should not attempt to lower prostate cancer risk by sunbathing because of the risk of skin cancer induced by this practice. They stated, "If future studies continue to show reductions in prostate cancer risk associated with sun exposure, increasing vitamin D intake from diet and supplements may be the safest solution to achieve adequate levels of vitamin D."
June 13, 2005
Calcium and vitamin D help prevent PMS
The June 13 2005 issue of Archives of Internal Medicine (http://archinte.ama-assn.org/) published the findings of Elizabeth R. Bertone-Johnson, Sc.D., of the University of Massachusetts, Amherst, and colleagues that increasing calcium and vitamin D in the diet may lower the risk of developing premenstrual syndrome (PMS), a cluster of symptoms that occur during the week or so prior to the onset a woman's menses, some of which can interefere with normal activities.
The current investigation is a substudy of the Nurses' Health Study II, which enrolled female nurses between the ages of 25 and 42 in 1989. Participants were asked if they had been diagnosed with PMS in questionnaires completed upon enrollment, and every two years thereafter through 2001. One thousand fifty-seven women diagnosed with PMS and 1,968 participants who were free of the condition were included in the current analysis. Calcium and vitamin D from food, supplements and antacids was measured from food frequency questionnaires completed in 1991, 1995 and 1999.
The researchers found that higher intake of total calcium and calcium from food was associated with a lower risk of developing PMS over the course of the study, beginning in 1991. According to the authors, the lack of a similar association when calcium supplements alone were examined may be due to the fact that the intake levels in the small proportion of the participants using them was too low. Total and food sourced vitamin D intake was also inversely associated with PMS. The authors conclude, "Our findings, together with those from several small randomized trials that found calcium supplements to be effective in treating PMS, suggest that a high intake of calcium and vitamin D may reduce the risk of PMS. Clinical trials of this issue are warranted. In the interim, given that calcium and vitamin D may also reduce risk of osteoporosis and some cancers, clinicians may consider recommending these nutrients even for younger women."
June 10, 2005
Linolenic acid intake inversely correlated with calcified atherosclerotic plaque
A study published in the June 7 2005 issue of the journal Circulation (http://circ.ahajournals.org/) found a decreased prevalence of calcified atherosclerotic plaque in the coronary arteries of individuals whose diets included higher amounts of linolenic acid. Alpha-linolenic acid is a fatty acid found in salad dressings, flax and canola oil, and gamma-linolenic acid is found in small amounts in animal fats, and in borage, black currant and evening primrose oils.
Eight hundred forty-five men and 1,159 women participants in the National Heart, Lung, and Blood Institute Family Heart Study (FHS) were included in the current study. Linolenic acid intake was quantified from food frequency questionnaires completed by the participants. The presence and extent of coronary artery calcified atherosclerotic plaque was measured by CT scans conducted approximately 7 years after the subjects' initial visits.
Linolenic intake ranged from 230 milligrams to 3.48 grams per day for men and 170 milligrams to 2.29 grams for women. The researchers found an inverse dose-dependent association between linolenic acid consumption and the presence of calcified atherosclerotic plaque as determined by CT. Individuals in the highest 20 percent of linolenic acid intake experienced a 65 percent lower risk of having the plaques than those in the lowest one-fifth of linolenic acid intake.
Although the researchers were not able to separate alpha from gamma-linolenic acid in this study, they note that alpha-linolenic acid is a precursor of eicosapentaenoic acid (EPA) which can inhibit arachidonic acid metabolism, thereby preventing the formation of proinflammatory markers. Gamma-linolenic acid also yields antiinflammatory products. Because calcium deposition in the arteries is an early stage in atherosclerosis and inflammation plays a key role in all phases of the process, linolenic acid may reduce coronary calcification risk by its antiinflammatory properties.
(Djousse L et al. Dietary linolenic acid is inversely associated with calcified atherosclerotic plaque in the coronary arteries. Circulation. 2005 June 7;111(22):2921-2926.
June 8, 2005
Omega-3 fatty acids boost cancer fighting effect of antioxidant drug
In a study published on June 7 2005 in the journal Breast Cancer Research (http://breast-cancer-research.com/) Dr Rafat Siddiqui of the Methodist Research Institute and Indiana University in Indianapolis, and colleagues reported that the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) boost the anticancer activity of the drug propofol when conjugated with the drug. Propofol is an anesthetic with antioxidant properties that inhibits cancer cell migration by 5 to 10 percent.
When conjugated with propofol, breast cancer cell adhesion was inhibited by 15 percent with DHA and 30 percent with EPA, while either omega-3 fatty acid alone had only a slight benefit and propofol alone slightly increased cell adhesion compared to control cells treated with ethanol. In addition, cell migration was cut in half and programmed cell self-destruction known as apoptosis increased by 40 percent when breast cell cultures were treated with the conjugates. These results show that the omega-3/drug combinations may be helpful to prevent breast cancer cells from developing into malignant tumors and metastasizing.
The authors explain that EPA and DHA might boost the activity of propofol by facilitating its absorption into the cancerous cells. The ability of drugs to be taken up by the cells has frequently proven to be an obstacle to their effectiveness. They write, "It is possible that these conjugates provide a mechanism whereby propofol can be retained in cell membranes for a longer duration and therefore enhance its anticancer effects".
"These results suggest that the novel propofol-DHA and propofol-EPA conjugates reported here may be useful for the treatment of breast cancer," the authors conclude. Dr Siddiqui's team plans to test the conjugates on other cancer cell lines.
(Siddiqui RA et al. Anticancer properties of propofol-docosahexaenoate and propofol-eicosapentaenoate on breast cancer cells. Breast Cancer Research. 2005 June 7:7(5):645-654.)
June 6, 2005
Supplement combo improves peripheral vascular disease symptoms
A report published in the June 2005 issue of the Journal of Nutrition (http://www.nutrition.org/) published the findings of researchers in Granada, Spain, that a combination of nutrients known to help protect against cardiovascular disease also helps to improve the risk factors and symptoms of peripheral vascular disease (PVD). Peripheral vascular disease is an occlusion of the arteries of the legs caused by body-wide atherosclerosis. The condition frequently manifests as intermittent claudication, which is a cramping pain in the legs that occurs during walking, caused by inadequate blood supply to the muscles due to atherosclerotic blockages.
Sixty men with peripheral vascular disease with intermittent claudication were divided to receive a daily fortified milk product that contained 200 milligrams eicosapentaenoic acid (EPA), 130 milligrams docosahexaenoic acid (DHA), 5.12 grams oleic acid, 150 micrograms folic acid, and vitamins A, B6, D, and E, or skimmed milk with added vitamins A and D for 12 months. The participants were interviewed and blood samples were drawn at the beginning of the study and every three months until the study's conclusion.
Pain free walking distance, a measure of how far a PVD patient can walk before the onset of intermittent claudication, progressively increased after the third month by up to 3.5 times in the group that received the supplements, while the group that received the skim milk experienced nonsignificant improvements. Ankle-brachial index pressure, which is the ratio of the ankle systolic pressure to brachial artery pressure, also improved in the supplemented group, but not in the nonsupplemented group. The men receiving the supplements experienced a drop in total cholesterol and ApoB, and homocysteine levels were reduced among those in whom it was previously elevated.
The study is the first to utilize this combination of nutrients in PVD, and the findings provide evidence for the role of nutrition in reducing the symptoms of the disease.
June 3, 2005
Low plasma vitamin B6 associated with Alzheimer's brain lesions
A letter published in the June 2005 Journal of the American Geriatrics Society (http://www.blackwell-synergy.com/loi/jgs) reported an increase in the white matter lesions in Alzheimer's disease patients associated with reduced levels of vitamin B6. Lesions in the white matter of the brain are associated with brain aging and may reflect chronic cerebral ischemia, although their role in Alzheimer's disease has not been defined.
Dutch researchers studied 123 Alzheimer's disease patients who visited theVU University Medical Center between 1997 and 2002. White matter lesions of the subcortical and periventricular regions of the brain and areas of atrophy were determined by magnetic resonance imaging. Dementia severity was assessed by the Mini-Mental State Examination and blood samples were collected and analysed for pyridoxal-5-phosphate, which is the biologically active form of vitamin B6.
Periventricular white matter lesions were identified in 63 participants, and subcortical lesions in 88. Vitamin B6 levels were found to encompass a wide range of values, from as low as 9 nanomoles per liter to 401 nanomoles per liter of plasma. Levels of the vitamin were inversely associated with increased periventricular as well as subcortical white matter lesions.
The authors write that homocysteine, which is partly metabolized through a reaction involving vitamin B6 and can therefore be elevated in states of vitamin B6 deficiency, could be involved in the current findings. Homocysteine can initiate or accelerate atherosclerosis, which is related to the formation of white matter lesions, although one study found that the low vitamin B6 levels observed in Alzheimer's disease patients were not related to cardiovascular disease. They conclude that the results "may provide a rationale for intervention studies examining the effect of vitamin B6 supplementation on vascular changes in the brain in relation to the incidence and course of Alzheimer's disease." (Mulder C et al, Low vitamin B6 levels are associated with white matter lesions in Alzheimer's disease, JAGS 53:1073-74, 2005.)
June 1, 2005
New freezing technique allows women treated for cancer to preserve eggs
A presentation at the World Congress on In Vitro Fertilization, Assisted Reproduction and Genetics held on May 29 2005 in Istanbul revealed a new technique that could benefit women whose chemotherapy and radiation treatments have interfered with their ability to have children. Researchers at the University of Michigan Comprehensive Cancer Center used a process of freezing cells called vitrification which greatly improves the survival of eggs that are frozen. Previous freezing techniques have produced limited egg survival due to ice crystal formation upon thawing. With vitrification, cells are rapidly cooled so that the transformation to a solid state is instantaneous and no ice crystals form.
Utilizing mouse eggs, Gary D Smith, PhD, who is associate professor of obstetrics and gynecology, urology, and molecular and integrative physiology at the University of Michigan Medical School, found that 80 percent of the vitrified eggs were able to be fertilized via intracytoplasmic sperm injection (ICSI), a technique that involves injecting an egg with a single sperm cell. Thirty percent of the fertilized eggs resulted in live births, a rate comparable to that of fertilized eggs that are not vitrified.
University of Michigan’s Comprehensive Cancer Center is planning to conduct a clinical trial this year using the procedure for women who are facing cancer treatment. When the women whose eggs have been frozen wish to become pregnant, the eggs will be fertilized and transferred to the uterus in the same manner that in-vitro fertilization utilizes with frozen embryos.
Dr Smith stated, “With traditional slow-freeze techniques, just over half the eggs survive the thawing process. Using vitrification, we are getting 98 percent survival. For a woman with cancer, these are the only eggs she's ever going to have, so it's important that as many as possible remain viable."