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Low Vitamin D levels common in breast cancer

More than half of women with breast cancer have low vitamin D levels, British researchers report.”Women with breast cancer should be tested for vitamin D levels and offered supplements, if necessary,” says researcher Sonia Li, MD, of the Mount Vernon Cancer Centre in Middlesex, England. The findings were presented at the San Antonio Breast Cancer Symposium.

Some studies have suggested a link between low vitamin levels and breast cancer risk and progression, but others have not, she says. No studies have proven cause and effect. Previous research suggests a biologic rationale for vitamin D putting the brakes on breast cancer development and spread, Li says. Breast cancer cells have vitamin D receptors, and when these receptors are activated by vitamin D, it triggers a series of molecular changes that can slow cell growth and cause cells to die, she says. Even if it does not have a direct effect on the tumor, vitamin D is needed to maintain the bone health of women with breast cancer, Li says. That's especially important given the increasing use of aromatase inhibitors, which carry an increased risk of bone fractures, she says.

Vitamin D is found in some foods, especially milk and fortified cereals, and is made by the body after exposure to sunlight. It is necessary for bone health.

For the study, Li and colleagues collected blood samples from 166 women with breast cancer and measured their levels of vitamin D. Of the total, 46% had vitamin D insufficiency, defined as levels between 12.5 and 50 nanomoles per liter (nmol/L) of blood. Another 6% had vitamin D deficiency, with levels lower than 12.5 nmol/L. When ethnicity was considered, vitamin D levels were lower in Asian women than in white or other women: an average of about 36 nmol/L vs. 61 nmol/L and 39 nmol/L, respectively.

The researchers theorized that vitamin D levels would be higher in the summer, when there are more daylight hours, but the study showed no association between vitamin D levels and seasons. Last month, the U.S. Institute of Medicine issued updated guidelines stating that a blood level of 50 nmol/L (or 20 nanograms/milliliter) is sufficient for 97% of people.

This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the “peer review” process, in which outside experts scrutinize the data prior to publication in a medical journal.

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Poor Diet Metabolism, Lack of Exercise Increases Asthma Risk in Kids

Metabolic syndrome is a cluster of risk factors which can result in heart disease and diabetes. Researchers have now found that poor diet and lack of exercise that lead to an imbalance in metabolism may also increase a child's risk of developing asthma.

Dr. Giovanni Piedimonte and researchers from West Virginia University School of Medicine analyzed data from nearly 18,000 children aged 4 to 12 years who were taking part in the Coronary Artery Risk Detection in Appalachian Communities (CARDIAC) project. Factors considered included triglyceride levels and evidence of acanthosis nigricans, which are raised patches of brown skin that are often biomarkers for insulin resistance.

The team also considered body mass index or BMI, and almost 21% of the children were considered obese. Fourteen percent of the children had asthma.

The researchers found that asthma prevalence among the children was strongly associated with certain symptoms of metabolic syndrome including dyslipidemia and abnormal glucose metabolism, but not weight status. Although those who were obese were more likely to have asthma, even children of a healthy weight who had imbalanced metabolism were at increased risk.

Certain metabolic factors participate in the asthma disease process by contributing to inflammation of the airways in the lungs and hyperreactivity (contraction of smooth muscle in the bronchial walls), says Dr. Piedimonte. He says that strict monitoring and control of triglyceride and glucose levels early in life may play a role in the management of chronic asthma in children.

Dr. Piedimonte would like to see the findings used as further support for universal lipid screening in children. “The rationale is that by using selective screening, we would have missed over a third of children with significant genetic dyslipidemia,” he said.

Both poor diet – one lacking in antioxidants but high in fat – and inadequate exercise play a role in the metabolic syndrome, a group of risk factors that increase the risk for coronary artery disease, stroke, and type 2 diabetes. The goal of treatment is often weight loss (if overweight), a minimum of 30 minutes of daily moderate intensity exercise, and a lowering of cholesterol, blood pressure and blood sugar through diet or medication.

Source reference:
Cottrell L, et al “Metabolic abnormalities in children with asthma” Am J Respir Crit Care Med 2010; DOI: 10.1164/rccm.201004-0603OC.

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