April 11, 2007

Vitamin C -- a Nutritional Approach to Managing Exercise-induced Asthma

(HealthNewsDigest.com)- A new study from Indiana University has found that large doses of vitamin C can stem the cycle of inflammation that contributes to exercise-induced asthma, a wheezing and tightness of the chest that can occur after rigorous exercise.

The study, involving asthma sufferers who have EIA, found that participants who had taken 1,500 mg of ascorbic acid for two weeks showed improved post-exercise lung function and a decreased concentration of biomarkers in their urine related to airway inflammation. This included the infamous leukotrienes, which play a key role in the inflammation that can lead to EIA.

The findings, appearing in the online issue of Respiratory Medicine, could provide asthma suffers a nutrition-based tool for controlling their EIA symptoms, even if it means continuing with their daily maintenance medications. "Ascorbic acid supplementation could offer asthmatics better control even if it means no change in their medication status," said lead author Sandra Tecklenburg, a doctoral candidate in IU Bloomington's Department of Kinesiology and an assistant coach for IU women's track and cross country teams. "They could have more symptom-free days or just feel better. For me, that's important because I'd like to see the asthmatic athletes I'm coaching be able to finish a workout or not have to drop out of a race, or just perform better in general."

About the placebo-controlled study:

The double-blind, randomized, crossover study involved eight asthmatics who have EIA, also called exercise-induced bronchoconstriction. In turn, they received 1,500 mg of vitamin C daily for two weeks and ran on a treadmill. Their urine was examined for a variety of inflammation biomarkers related to lung function, making this the first study involving vitamin C to examine such biomarkers.

Post-exercise lung function dropped by an average 6.4 percent for study participants receiving vitamin C supplementation, compared to drops of 14.3 percent and 12.9 percent for participants on a normal diet or receiving a placebo respectively. A drop of less than 10 percent is no longer considered EIA. The ascorbic acid diet reduced the maximum post-exercise fall in forced expiratory volume in 1-sec (FEV1) by about 56 percent compared to the usual diet.

The concentration of the airway inflammatory biomarkers (e.g., leukotrienes and prostaglandins) in the urine decreased substantially following exercise on the ascorbic acid diet compared to the usual and placebo diets. Tecklenburg said this is particularly notable concerning the involvement of these biomarkers in the pathogenesis of EIA.

Vitamin C is an antioxidant. Tecklenburg said the study found it helped reduce the oxidative stress that can lead to EIA by disrupting the cycle caused when free radicals trigger an immune response in the body, which then produces more free radicals. Ascorbic acid is water soluble so it does not become toxic in large quantities. Tecklenburg said none of the study subjects reported adverse side effects from the dosage, which is more than 10 times the recommended daily allowance for adults. Co-authors of the study are Timothy Mickleborough, an associate professor in the Department of Kinesiology; Alyce Fly, associate professor in the Department of Applied Health Science; Yeon Bai, doctoral candidate in the department of Applied Health Science; and Joel Stager, professor in the Department of Kinesiology.

For a copy of the study, contact newsroom@elsevier.com. Tracy James, IU Media Relations, might also be of assistance. She can be reached at 812-855-0084 and traljame@indiana.edu.

Tecklenburg can be reached at stecklen@indiana.edu. Mickleborough can be reached at 812-855-0753 and tmickleb@indiana.edu. Top

Healthy spring cleaning. Spring cleaning is a must for clearing out dust and clutter, but many cleaning products are potentially toxic, said environmental science professor Diane Henshel. Below are her tips on reducing health hazards in your spring cleaning routine.

Target dust and mold, which are potential allergens. Henshel advised opening windows to permit air circulation, and vacuuming floors, furniture and ceiling corners thoroughly. When it's warm out, place air pillows, cushions and rugs in the sun to kill dust mites. Laundering bed and bath linens is another must for keeping mold and dust at bay. "Make sure you actually change the sheets every week, and wash sheets and towels in hot water," she said.

Nix fragranced detergents and beware dry cleaning fumes. Henshel said she worries that chemical residues meant to impart scent may also cause irritation to the skin or lungs. And while fragranced detergents carry a potential health risk, many dry cleaning chemicals are an indisputable hazard, she said. "The fumes from cleaners that use PERC (perchloroethylene) can harm the liver, kidneys or brain. Depending on the type of cleaner, it can take weeks or even months for those chemicals to evaporate," she said. Henshel recommends that clothes be aired after dry cleaning and that customers ask about treatments that do not use PERC.

Read the ingredients list. Just as customers should be on the lookout for unhealthy ingredients in packaged foods, becoming literate in cleaning ingredients is a key factor in avoiding exposure to toxic chemicals through the skin, lungs and eyes. "Become aware of what you are using on a regular basis and check out the ingredients on the internet," she said. She recommends national health organization sites such as the Agency for Toxic Substance and Disease Registry, http://www.atsdr.cdc.gov/.

Ventilate and create a barrier. "If your eyes water when you use a product, it's a really good sign you need more ventilation. And if your hands are raw, it's a good sign you need gloves," Henshel said. She noted that many cleaning products are harsher than necessary, especially those containing bleach. She recommended a gentle, all-purpose cleaner or natural alternatives like vinegar and baking soda for most household cleaning.

Source: www.healthnewsdigest.com