Weight loss, combined with vitamin D, reduces inflammation linked to cancer, chronic disease
"We know from our previous studies that by losing weight, people can reduce their overall levels of inflammation, and there is some evidence suggesting that taking vitamin D supplements can have a similar effect if one has insufficient levels of the nutrient," said lead and corresponding author Catherine Duggan, Ph.D., a principal staff scientist in the Public Health Sciences Division at Fred Hutch. However, it has not been known whether combining the two -- weight loss and vitamin D -- would further boost this effect. "It's the first study to test whether adding vitamin D augments the considerable effect of weight loss on inflammatory biomarkers," she said.
To explore this question, Duggan and colleagues recruited 218 healthy, overweight older women who had lower-than-recommended levels of vitamin D (less than 32 ng/mL). The women then took part in a 12-month diet and exercise program (including 45 minutes of moderate-to-vigorous exercise five days a week). Half of the study participants were randomly selected to receive 2,000 IU of vitamin D daily for the duration of the year-long trial, and the other half received an identical-appearing placebo, or dummy vitamin. Biomarkers of inflammation were measured at the beginning and end of the study. The researchers then compared changes in these levels between the two groups.
At the end of the study, all of the participants had reduced levels of inflammation, regardless of whether they took vitamin D, "which highlights the importance of weight loss in reducing inflammation," Duggan said. However, those who saw the most significant decline in markers of inflammation were those who took vitamin D and lost 5 to 10 percent of their baseline weight. These study participants had a 37 percent reduction in a pro-inflammatory cytokine called interleukin-6, or IL-6, as compared to those in the placebo group, who saw a 17.2 percent reduction in IL-6. The researchers found similar results among women in the vitamin D group who lost more than 10 percent of their starting weight. While IL-6 has normal functions in the body, elevated levels are associated with an increased risk of developing certain cancers and diabetes and may be implicated as a cause of depression, Duggan said.
"We were quite surprised to see that vitamin D had an effect on an inflammation biomarker only among women who lost at least 5 percent of their baseline weight," Duggan said. "That suggests vitamin D can augment the effect of weight loss on inflammation."
Vitamin D is a steroid hormone that has multiple functions beyond its widely recognized role in regulating calcium levels and bone metabolism. Vitamin D receptors are found in more than 30 cell types and the research focus around this nutrient recently has shifted from bone health to vitamin D's effect on cancer, cardiovascular health and weight loss, among other health issues.
Inflammation occurs when the body is exposed to pathogens, such as bacteria or viruses, which puts the immune system in overdrive until the "attack" ceases and the inflammatory response abates. Overweight or obese people, however, exist in a state of chronic inflammation. This sustained upregulation of the inflammatory response occurs because fat tissue continually produces cytokines, molecules that are usually only present for a short time, while the body is fighting infection, for example.
"It is thought that this state of chronic inflammation is pro-tumorigenic, that is, it encourages the growth of cancer cells," she said. There is also some evidence that increased body mass "dilutes" vitamin D, possibly by sequestering it in fat tissue.
"Weight loss reduces inflammation, and thus represents another mechanism for reducing cancer risk," Duggan said. "If ensuring that vitamin D levels are replete, or at an optimum level, can decrease inflammation over and above that of weight loss alone, that can be an important addition to the tools people can use to reduce their cancer risk."
Duggan encourages women to speak to their health care providers about measuring their levels of vitamin D to determine the most appropriate dosage.
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The above post is reprinted from materials provided by Fred Hutchinson Cancer Research Center. Note: Materials may be edited for content and length.
'Drink when thirsty' to avoid fatal drops in blood sodium levels during exercise
For hikers, football players, endurance athletes, and a growing range of elite and recreational exercisers, the best approach to preventing potentially serious reductions in blood sodium level is to drink when thirsty, according to an updated consensus statement on exercise-associated hyponatremia (EAH).
"Using the innate thirst mechanism to guide fluid consumption is a strategy that should limit drinking in excess and developing hyponatremia (low blood sodium) while providing sufficient fluid to prevent excessive dehydration," according to recommendations developed at this year's 3rd International Exercise-Associated Hyponatremia Consensus Development Conference. Tamara Hew-Butler, DPM, PhD, of Oakland University, Rochester, Mich., is lead author of the updated report.
EAH Deaths Are Preventable "If We Just Listen to Our Bodies"
The Consensus Panel reconvened to revise previous recommendations in response to the largely preventable deaths of two high school football players from dilutional EAH last summer. "Our major goal was to re-educate the public on the hazards of drinking beyond thirst during exercise," Dr. Hew-Butler comments.
The updated statement emphasizes a more balanced approach to hydration -- especially during the summer months, when exercising in the heat increases the risk for developing dangerously low blood sodium levels associated with overdrinking. Dr. Hew-Butler adds, "The release of these recommendations is particularly timely, just before sports training camps and marathon training begins within the United States -- where the majority of EAH deaths have occurred." The full statement is now available as a free download on the journal website: www.cjsportsmed.com/.
Exercise-associated hyponatremia -- sometimes called "water intoxication" -- refers to reductions in the body's sodium level occurring during or up to 24 hours after physical activity. Especially before the drop in sodium level becomes too severe, EAH may have no or only mild symptoms.
When symptoms occur, they typically include headache, vomiting, and confusion or seizures, resulting from swelling of the brain (cerebral edema). Without immediate treatment, severe EAH can be rapidly fatal. One large study found that symptomatic EAH occurred in one percent of athletes in endurance events. Asymptomatic EAH developed in another six percent of participants.
Sustained, excessive intake of water, sports drinks, or other fluids -- exceeding the body's ability to eliminate fluids in the form of sweat and urine -- is the major risk factor for EAH. The excess fluid dilutes the body's sodium level, interfering with normal regulatory processes.
Since drinking too much is the main cause of EAH, the most effective prevention is drinking less. "The safest individualized hydration strategy before, during and immediately following exercise is to drink palatable fluids when thirsty," according to the Consensus Panel.
Some athletes may drink too much because they've heard advice to "drink before they get thirsty" in order to avoid dehydration. The authors note that drinking when thirsty will not only prevent EAH, but also prevent possible drops in performance due to dehydration.
The statement includes recommendations for healthcare professionals -- emphasizing that EAH treatment should be guided by the severity of symptoms, not just the individual's sodium level. It also highlights the need for education on measures to reduce excessive fluid intake, targeting athletes and support teams.
Athletes and coaches must recognize the need for balanced hydration before, during and immediately following exercise to prevent further morbidity and mortality associated with 'forced hydration' practices," Dr. Hew-Butler adds. "Every single EAH death is tragic and preventable, if we just listen to our bodies and let go of the pervasive advice that if a little is good, than more must be better."
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The above post is reprinted from materials provided by Wolters Kluwer Health: Lippincott Williams and Wilkins. Note: Materials may be edited for content and length.