Calcium/exercise combo essential for building bone mass
A research paper published in the October 2004 issue of the Journal of Applied Physiology has found that both exercise and sufficient calcium are needed to build adequate bone mass in prepubescent children. Children need 550 milligrams calcium per day according to the UK government, but in actuality they may need a greater amount. Additionally, sufficient levels of activity are not always attained by this and other age groups.
In one of the few studies to examine the interactions between calcium intake and activity levels, Roger G. Eston of the Children's Health and Exercise Research Centre at the University of Exeter in England and colleagues at the University of Wales provided 38 boys and 38 girls aged 8 to 11 with accelerometers to track their exercise levels for up to seven days. Four day food diaries provided data on the children's calcium intake. Bone mineral content and bone mineral density were measured for the total body, proximal femur and femur neck within two weeks of the physical activity monitoring.
The research team found that found that neither sufficient calcium or exercise alone were optimally effective in building and retaining bone mass, but that a combination of 700 to 800 milligrams per day calcium, plus 25 to 40 minutes of vigorous exercise synergistically provided the greatest benefit. Dr Eston commented, “You don't have to jump rope for half an hour. That would be considered very hard. In reality we are talking about the sort of energy you would expect kids to expend when playing around outside with a ball or rope. A brisk walk at about 4 miles per hour would do the trick. We are talking about raising the resting energy levels by about 6-8 times. The idea is to 'accumulate' this sort of energy expenditure over the day to total about half an hour.”
Increased folic acid intake dramatically reduces Canadian neural tube defect incidence
A study published online in Biomed Central Pregnancy and Childbirth on September 26 2004 has found that an increase in the consumption of folic acid reduced the incidence of infants born with neural tube defects by 78 percent in the Canadian province of Newfoundland and Labrador. Folic acid, a member of the B complex family of vitamins, has been found to help protect women from giving birth to infants with neural tube defects and other birth defects, and its addition to flour, cornmeal and pasta in Canada has been mandated by the government since 1998.
Dr. Catherine McCourt, of the Population and Public Health Branch of Health Canada, and colleagues found that neural tube defects, which averaged 4.36 per 1000 births between 1991 and 1997, dropped to 0.96 per 1000 births between 1998 and 2001 following the initiation of folic acid fortification. Food fortification was found to increase folic acid intake in women between the ages of 19 and 44 by 70 micrograms per day, and to elevate blood levels significantly. Additionally, the use of folic acid supplements by women of reproductive age rose from 17 percent to 28 percent during the period studied, making it impossible to separate supplementation's effects from those of fortification on the reduction in neural tube defects.
This study also helped lay to rest long held fears that increased folic acid intake would mask the symptoms of a vitamin B12 deficiency. The current study found no decline in vitamin B12 status among seniors or any other evidence that the increase in blood folate levels masked a deficiency of vitamin B12.
The study supports continued food fortification. Additionally, the authors conclude that, "public education regarding folic acid supplement use by women of childbearing age should continue."
Soy foods could halt breast cancer spread
A study conducted at the University of Ulster in Northern Ireland has concluded that consumption of a greater quantity of soy-rich foods such as soy beverages could reduce the spread of breast cancer. Soy isoflavones possess a hormone-like effect, and have been found to help protect against the development of breast and prostate cancer, as well as other conditions such as high cholesterol. The study was published in the May 10, 2004 issue of the journal, Cancer Letters.
Dr Pamela Magee and colleagues administered the soy isoflavones genistein, glycitein, daidzein, equol, and O-desmethylangolensin; soy lignans, and a soy phytoestrogen known as coumestrol to cultured metastatic breast cancer cells and observed their effect on the cells' invasiveness. They found that the isoflavones and coumestrol had a dose-dependent inhibitory effect on breast cancer cell invasion, while lignans demonstrated minimal effects. None of the compounds decreased cell viability, demonstrating their potential as chemoprotective agents.
Dr Magee commented, "Although recent advances have been made in tumour detection and treatment, the spread of cancer remains a significant cause of mortality. The invasion of cancerous cells from their site of origin into the neighbouring environment enables cancerous cells to travel and grow at new sites within the body. Any agent, therefore, which can prevent the invasive process could become a powerful tool in the prevention of cancer spread."
“These novel findings seem to indicate that eating a soy rich products such as soy milk, soy drinks and desserts, could have an important role in preventing the spread of cancer cells in the body,” Dr Magee stated. “Further studies in human volunteers are now needed to confirm whether soy isoflavones will protect against breast cancer spread in patients.”
More on inflammation
In a report published in the September 21 2004 issue of the journal Circulation, researchers from the State University of New York at Buffalo revealed for the first time that mononuclear white blood cells known as lymphocytes and monocytes exist in a proinflammatory state in obese individuals, putting them at risk for heart disease and/or diabetes. The finding contributes to a growing body of evidence implicating chronic inflammation in cardiovascular disease, diabetes and other illnesses.
The study compared blood samples obtained from 16 normal weight participants and 16 obese subjects with similar glucose levels. The researchers found that the proinflammatory status of the blood mononuclear cells, as determined by measuring nuclear factor kappa-beta binding to DNA in nuclear extracts, was significantly higher in obese individuals. It was also discovered that the inhibitor of nuclear factor kappa-beta was lower in the obese subjects. When insulin resistance was calculated, that of obese subjects was found to be an average of three times higher than that of the normal participants. Additionally, obese participants had higher plasma levels of interleukin-6, tumor necrosis factor-alpha, C-reactive protein, and other markers of inflammation.
Senior author and head of UB's Division of Endocrinology, Diabetes and Metabolism, Paresh Dandona, MD, PhD, observed, "These cells are creating a lot of nuisance in the obese. They enter the artery and set up atherosclerosis. They activate fat cells to produce more proinflammatory factors. They interfere with insulin signaling, causing insulin resistance. They even enter the brain."
The study’s discovery could lead to the development of a blood test that would warn people of their increased risk of cardiovascular disease or diabetes. Dr Dardona recommends a change of diet or the addition of medication to combat the inflammatory state.
Curcumin fights melanoma in vitro and in vivo
The September 2004 issue of the International Journal of Cancer (http://www3.interscience.wiley.com/cgi-bin/jhome/29331) published the findings of researchers in Reims, France, that curcumin has an antitumor effect in cell cultures of melanoma and in mice with the disease. Curcumin is derived from turmeric, a spice commonly used in Indian and other cuisines that has been found to be protective against some cancers as well as other diseases.
In the in vitro experiments, the research team administered curcumin to single layers of mouse melanoma cells and found a dose-dependent decrease in cell viability regardless of the amount of time that the cells were exposed. They also studied curcumin’s effect on cells grown in three dimensional cultures that are more like solid tumors found in living organisms. Curcumin increased cell death in these cultures as well, although the cells were more resistant than the single layer cultures. Further investigation revealed that programmed cell death, known as apoptosis, was responsible for the antitumor effect observed in these experiments, which has been demonstrated in other studies.
To study curcumin’s antitumoral effect in vitro, a group of mice with melanoma were pretreated with an immune therapy that contained proteins derived from the melanoma cells, while another group was treated with curcumin, and a third group received both treatments. While each treatment alone resulted in little benefit, the combination significantly inhibited tumor growth and improved immune response in the mice that received it. When survival was evaluated, the immune preparation and curcumin were found to similarly enhance median survival time (by 48.6 percent and 45.7 percent respectively), and the combined treatments further increased median survival time by 82.8 percent compared to untreated mice.
The authors conclude that the study “shows that curcumin may provide a valuable tool for the development of a therapeutic combination against melanoma.”
Women's folic acid supplement use at all time high
The recommendation to women of childbearing age to increase their intake of folic acid appears to have been heeded, according to a survey published in the September 17 2004 issue of Morbidity & Mortality Weekly Report (http://www.cdc.gov/mmwr/index.html). The survey, conducted by the March of Dimes, found that 40 percent of American women of reproductive age reported taking a multinutrient supplement that contains folic acid, the highest number yet since the March of Dimes began surveying women during the previous decade.
Folic acid is a member of the B complex found in leafy green vegetables that has been demonstrated to be vital for the prevention of neural tube defects in unborn children. Women of childbearing age have been advised to consume supplements containing the vitamin to help protect against this and possibly other birth defects in their offspring.
The current study involved telephone interviews of 2,012 women aged 18 to 45 in 2004. The researchers found that the use of supplements containing folic acid by all women was up 32 percent from 2003. Among those who were not pregnant, intake was increased by 30 percent. March of Dimes president Dr. Jennifer L. Howse commented, "Frankly, we're surprised at this increase, but it's good news. The increase is especially important because we've been very worried about the effects on mothers and babies of popular low-carbohydrate diets that drastically reduce grain foods enriched with folic acid, such as bread and pasta. However, our survey finds that 49 percent of women who have been on low-carb diets in the past six months said they actually took a daily multivitamin containing folic acid. So perhaps these women are taking their vitamins because they realize they're missing out on important food groups."
Glutathione levels inversely associated with cardiovascular disease risk
The September 2004 issue of the American Heart Association journal Stroke (http://stroke.ahajournals.org/) published the findings of Japanese researchers that higher levels of plasma glutathione (GSH) are associated with a lower incidence of cardiovascular disease, particularly cerebral small vessel disease. Glutathione is formed in the body from three amino acids (cysteine, glycine, and glutamic acid), and forms a part of the antioxidant enzyme glutathione peroxidase.
The researchers studied individuals residing in Hisayama, Japan, who have been part of an ongoing study of cardiovascular disease since 1961. One hundred thirty-four subjects with cardiovascular disease and 435 gender and age-matched controls were enrolled in the current investigation.
Blood samples were analyzed for plasma glutathione, homocysteine and other factors. Unsurprisingly, homocysteine levels were found to be significantly higher in participants with cardiovascular disease than in those without it.
Adjusted values of plasma glutathione were significantly lower in those with cardiovascular disease. When participants were grouped according to their levels of glutathione and analyzed, systolic and diastolic blood pressure was found to decrease with rising levels of glutathione. The incidence of diabetes also fell as glutathione levels rose. Subjects whose glutathione levels were in the highest quarter of participants were found to have a 75 percent lower incidence of cardiovascular disease than those in the lowest one-fourth. When cardiovascular disease was broken down into types, subjects with cerebral infarction and cerebral hemorrhage maintained similar trends in risk reduction.
Glutathione may have a protective effect against cardiovascular disease through a direct antioxidant effect. The authors state that because there is evidence that orally consumed glutathione increases plasma levels in humans, “it is anticipated that oral administration of GSH is a possible therapeutic strategy for the prevention of CVD, although further studies . . . are essential.”
Study finds high-sensitivity C-reactive protein elevated in asymptomatic people with atherosclerosis
A report published in the September 13 2004 issue of the Archives of Internal Medicine (http://archinte.ama-assn.org/) described the finding of Mayo Clinic researchers that high-sensitivity C-reactive protein (hs -CRP) can be a marker for heart disease in people with no disease symptoms. C-reactive protein is increased in the blood during inflammation, and has recently emerged as a risk factor for cardiovascular disease when elevated.
The current study involved three hundred eighty-six men and women with a median age of 66 who were enrolled in the Stroke Prevention: Assessment of Risk in a Community study (SPARC). Participants underwent t ransesophageal echocardiography to provide images of the lining of the aorta, the main artery that leaves the heart. Blood tests measured high sensitivity-CRP and other factors.
Aortal atherosclerotic plaques were detected in 69 percent of the participants, and found to be associated with hs -CRP levels. In subjects with plaques, hs -CRP levels were independently associated with those that were 6 millimeters or more in thickness. Research team leader and Mayo Clinic cardiologist Bijoy Khandheria , MD, stated, "This study is important because for the first time it gives us data on cholesterol, hs -CRP and other risk factors from people randomly selected from the community, and lets us correlate those results with the presence or absence of plaques. We have known for some time that hs -CRP levels are elevated among patients with chest pain or other heart-related symptoms. This new study tells us high CRP is a sign that plaques likely are being formed in the arteries, even if the person feels healthy. Our findings provide a missing link between inflammatory markers in the bloodstream and the increased risk of a cardiovascular event such as a heart attack."
Melatonin helps prevent migraines
The first study to assess the effectiveness of melatonin as a preventive for migraine was published in the August 24, 2004 issue of the journal Neurology (http://www.neurology.org/). Melatonin is a hormone produced by the pineal gland in the brain which induces sleep and has been shown to have many other health benefits.
Twenty-nine women and five men with episodic migraine who experienced two to eight migraine headaches per month were enrolled in the current study conducted by researchers at the Hospital Israelita Albert Einstein in Sao Paulo, Brazil. Participants were given 3 milligrams melatonin to be taken thirty minutes before bedtime each night for a three month period. Headache frequency, intensity and duration, and the consumption of pain relievers were recorded.
Of the thirty-two patients who completed the study, 78.1 percent experienced at least a 50 percent reduction in headaches, and no participants reported an increase. Eight patients experienced no migraines during the study period, seven had a greater than 75 percent reduction, and ten experienced a 50 to 75 percent reduction in headaches after three months of treatment with melatonin, with signficant improvement demonstrated as early as one month. Duration, intensity, and the need for pain relief drugs also decreased over the course of the study.
In their discussion of the possible mechanisms of melatonin, the authors describe the circadian nature of some migraine attacks, which melatonin may affect. A possible anti-inflammatory effect as well as the ability to scavenge free radicals could also contribute to melatonin's protective effect against migraine. Other possible mechanisms are melatonin's ability to reduce proinflammatory cytokines, interfere with membrane stabilization, potentiate gamma-aminobutyric acid and opioids, protect against glutamate neurotoxicity, contribute to neurovascular regulation and modulate serotonin. The authors recommend a controlled study.
Does low melatonin contribute to childhood leukemia?
A conference on childhood leukemia held in London (Childhood leukaemia: incidence, causal mechanisms and prevention) was the site of a presentation on September 8 by experts who believe that increased light at night could be a contributor to the recent rise of the disease, which has increased by over 50 percent between 1950 and the year 2000.
Nighttime lighting disrupts circadian rhythms and suppresses the production of melatonin, a hormone released by the pineal gland in the brain that has antioxidant and other functions. Professor of Visual Neuroscience at Imperial College, London, Russell Foster, explained "Embedded within the genes of us, and almost all life on earth, are the instructions for a biological clock that marks the passage of approximately 24 hours. Until we turned our nights into days, and began to travel in aircraft across multiple time zones, we were largely unaware of these internal clocks. These clocks drive or alter our sleep patterns, alertness, mood, physical strength, blood pressure and every other aspect of our physiology and behaviour."
Melatonin expert and University of Texas professor of cellular and structural biology, Russel Reiter, further explained, "As an antioxidant, in many studies melatonin has been shown to protect DNA from oxidative damage. Once damaged, DNA may mutate and carcinogenesis may occur."
Dr Reiter reported a link between magnetic fields and childhood leukemia incidence, which may also be related to nighttime lighting, since magnetic fields appear to reduce melatonin levels as well. He stated, "If, in fact, melatonin levels are altered by magnetic fields, a potential relationship between these fields and cancer, including leukemia, would be possible."
The conference will also present information on other factors, such as radiation, viruses and diet that may play a role in the development of childhood leukemia.
Broccoli compound halts breast cancer growth
Whole body CT scans can increase cancer risk
The September 2004 issue of the journal Radiology ( http://radiology.rsnajnls.org/ ) published a special report by Daniel J Brenner PhD and Carl D Elliston, MA of Columbia University that warned against increased cancer risks incurred by individuals who undergo elective yearly full-body computed tomography (CT) scans. Clinics offering whole body CT screening advertise their service as providing an opportunity for early detection of cancerous tumors and other conditions, however, the individuals who patronize these clinics could be putting themselves at greater risk for some of the conditions they are trying to detect.
The duo studied atomic bomb mortality data related to radiation dosage, and compared the estimated dose of radiation received by a full-body CT scan. They found that the dose from one full body CT scan, which is almost one hundred times that of a mammogram, was almost that of the mean dose received by atomic bomb survivors who experienced a significant increase in cancer risk. A forty-five year old who had annual full-body scans for thirty years would experience a 1 in 50 risk of dying from cancer according to Brenner and Elliston's analysis. The authors note that different scanners deliver varying doses of radiation, modifying risk.
The report only considered individuals with no symptoms who elect to have the scans, not those who are referred for medical diagnosis.
Dr Brenner, who is a professor of radiation oncology and public health at Columbia University and the lead author of the report, commented, "Our research provides definitive evidence that radiation risk is associated with full-body CT scans. The radiation dose from a full-body CT scan is comparable to the doses received by some of the atomic-bomb survivors from Hiroshima and Nagasaki, where there is clear evidence of increased cancer risk."