Month: July 2008
Strong bones, a healthy immune system, protection against some types of cancer: Recent studies suggest there’s yet another item for the expanding list of Vitamin D benefits. Vitamin D, “the sunshine vitamin,” keeps the heart, the body’s long-distance runner, fit for life’s demands.
University of Michigan pharmacologist Robert U. Simpson, Ph.D., thinks it’s apt to call vitamin D “the heart tranquilizer.” In studies in rats, Simpson and his team report the first concrete evidence that treatment with activated vitamin D can protect against heart failure. Their results appear in the July issue of the Journal of Cardiovascular Pharmacology. In the study, treatments with activated vitamin D prevented heart muscle cells from growing bigger – the condition, called hypertrophy, in which the heart becomes enlarged and overworked in people with heart failure. The treatments prevented heart muscle cells from the over-stimulation and increased contractions associated with the
progression of heart failure.
About 5.3 million Americans have heart failure, a progressive, disabling condition in which the heart becomes enlarged as it is forced to work harder and harder, making it a challenge even to perform normal daily activities. Many people with heart disease or poorly controlled high blood pressure go on to experience a form of heart failure called congestive heart failure, in which the heart’s inability to pump blood around the body causes weakness and fluid build-up in lungs and limbs. Many people with heart failure, who tend to be older, have been found to be deficient in vitamin D.
“Heart failure will progress despite the best medications,” says Simpson, a professor of pharmacology at the U-M Medical School. “We think vitamin D retards that progression and protects the heart.”
The U-M researchers wanted to show whether a form of vitamin D could have beneficial effects on hearts that have developed or are at risk of developing
heart failure. They used a breed of laboratory rats predisposed to develop human-like heart failure. The researchers measured the effects of activated Vitamin D (1,25 dihydroxyvitamin D3, a form called calcitriol) in rats given a normal diet or a high-salt diet, compared to control group rats given either of the same two diets, but no vitamin D treatment. The rats on the high-salt diet were likely to develop heart failure within months.
The rats on the high-salt diet, comparable to the fast food that many humans feast on, quickly revealed the difference vitamin D could make. “From these animals, we have obtained exciting and very important results,” Simpson says.
After 13 weeks, the researchers found that the heart failure-prone rats on the high-salt diet that were given the calcitriol treatment had significantly lower levels of several key indicators of heart failure than the untreated high-salt diet rats in the study. The treated rats had lower heart weight. Also, the left ventricles of the treated rats’ hearts were smaller and their hearts worked less for each beat while blood pressure was maintained, indicating that their heart function did not deteriorate as it did in the untreated rats. Decreased heart weight, meaning that enlargement was not occurring, also showed up in the treated rats fed a normal diet, compared to their untreated counterparts. Simpson and his colleagues have explored vitamin D’s effects on heart muscle and the cardiovascular system for more than 20 years. In 1987, when Simpson showed the link between vitamin D and heart health, the idea seemed far-fetched and research funding was scarce. Now, a number of studies worldwide attest to the vitamin D-heart health link.
The new heart insights add to the growing awareness that widespread vitamin D deficiency—thought to affect one-third to one-half of U.S. adults middle-aged and older—may be putting people at greater risk of many common diseases. Pharmaceutical companies are developing anti-cancer drugs using vitamin D analogs, which are synthetic compounds that produce vitamin D’s effects. There’s also increasing interest in using vitamin D or its analogs to treat autoimmune disorders.
In more than a dozen types of tissues and cells in the body, activated vitamin acts as a powerful hormone, regulating expression of essential genes and rapidly activating already expressed enzymes and proteins. In the heart, Simpson’s team has revealed precisely how activated vitamin D connects with specific vitamin D receptors and produces its calming, protective effects. Those results appeared in the February issue of Endocrinology. Sunlight causes the skin to make activated vitamin D.
People also get vitamin D from certain foods and vitamin D supplements. Taking vitamin D supplements and for many people, getting sun exposure in safe ways, are certainly good options for people who want to keep their hearts healthy. But people with heart failure or at risk of heart failure will likely need a drug made of a compound or analog of vitamin D that will more powerfully produce vitamin D’s effects in the heart if they are to see improvement in their symptoms, Simpson says.
Vitamin D analogs already are on the market for some conditions. One present drawback of these compounds is that they tend to increase blood calcium to undesirable levels. Simpson’s lab is conducting studies of a specific analog which may be less toxic, so efforts to develop a vitamin Dbased drug to treat heart failure are moving a step closer to initial trials in people.
left: Heart muscle cells in untreated rats bred to develop heart failure show signs of disease: Cells are irregular in size and shape and show fibrotic lesions (areas in purple). Right: Heart muscle cells remain healthy in rats treated with calcitriol, the hormone that Vitamin D becomes in the body. (Credit: Image courtesy of University of Michigan Health System)
Exercise for Your Bone Health
Vital at every age for healthy bones, exercise is important for treating and preventing osteoporosis. Not only does exercise improve your bone health, it also increases muscle strength, coordination, and balance, and leads to better overall health.
Like muscle, bone is living tissue that responds to exercise by becoming stronger. Young women and men who exercise regularly generally achieve greater peak bone mass (maximum bone density and strength) than those who do not. For most people, bone mass peaks during the third decade of life. After that time, we can begin to lose bone. Women and men older than age 20 can help prevent bone loss with regular exercise. Exercising allows us to maintain muscle strength, coordination, and balance, which in turn help to prevent falls and related fractures. This is especially important for older adults and people who have been diagnosed with osteoporosis.
The Best Bone Building Exercise
The best exercise for your bones is the weight-bearing kind, which forces you to work against gravity. Some examples of weight-bearing exercises include lifting weights, walking, hiking, jogging, climbing stairs, tennis, and dancing. Examples of exercises that are not weight-bearing include swimming and bicycling. While these activities help build and maintain strong muscles and have excellent cardiovascular benefits, they are not the best way to exercise your bones.
If you have health problems – such as heart trouble, high blood pressure, diabetes, or obesity – or if you are over age 40, check with your doctor before you begin a regular exercise program. According to the Surgeon General, the optimal goal is at least 30 minutes of physical activity on most days, preferably daily. Listen to your body. When starting an exercise routine, you may have some muscle soreness and discomfort at the beginning, but this should not be painful or last more than 48 hours. If it does, you may be working too hard and need to ease up. STOP exercising if you have any chest pain or discomfort, and see your doctor before your next exercise session.
If you have osteoporosis, ask your doctor which activities are safe for you. If you have low bone mass, experts recommend that you protect your spine by avoiding exercises or activities that flex, bend, or twist it. Furthermore, you should avoid high-impact exercise in order to lower the risk of breaking a bone. You also might want to consult with an exercise specialist to learn the proper progression of activity, how to stretch and strengthen muscles safely, and how to correct poor posture habits. An exercise specialist should have a degree in exercise physiology, physical education, physical therapy, or a similar specialty. Be sure to ask if he or she is familiar with the special needs of people with osteoporosis.
A Complete Osteoporosis Program
Remember, exercise is only one part of an osteoporosis prevention or treatment program. Like a diet rich in calcium and vitamin D, exercise helps strengthen bones at any age. But proper exercise and diet may not be enough to stop bone loss caused by medical conditions, menopause, or lifestyle choices such as tobacco use and excessive alcohol consumption. It is important to speak with your doctor about your bone health. Discuss when you might be a candidate for a bone mineral density test. If you are diagnosed with low bone mass, ask what medications might help keep your
Almonds, as well as being high in vitamin E and other minerals, are also thought to have other health benefits, such as reducing cholesterol. Recently published work by the Institute of Food Research has identified potential prebiotic properties of almonds that could help improve our digestive health by increasing levels of beneficial gut bacteria.
Our digestive system maintains large population of bacteria that live in the colon. Prebiotics are non-digestible parts of foods that these bacteria can use to fuel their growth and activity. These ‘good’ bacteria form part of our body’s defense against harmful bacteria and play a role in the development of body’s immune system. The prebiotics work by stimulating the growth of these bacteria. However, in order to get to where they are needed prebiotics must be able to get through the upper part of the intestine without being digested or absorbed by the body.
Funded by the Almond Board of California, IFR scientists first used the Model Gut, a physical and biochemical simulator of the gastro-intestinal tract, to subject almonds to the same conditions experienced in the stomach and small intestine. They then added the digested almonds to an in vitro batch system to mimic the bacterial fermentation in the large intestine and monitored its effect on the populations of intestinal bacteria.
The study, published in Applied and Environmental Microbiology, found that finely ground almonds significantly increased the levels of certain beneficial gut bacteria. This effect was not seen when the fat content was removed from the almond preparation, suggesting that the beneficial bacteria use the almond lipid for growth, and this is the basis for the prebiotic effect of almonds.
Previous studies have shown that the amount of available lipid is reduced if the almonds are not processed, for example by grinding as in this study or by chewing. The length of time the almond spends in the digestive system also affects the amount of available lipids and proteins. More detailed studies on the digestibility of almonds are now required, and the prebiotic effect of almond lipids needs to be tested in human volunteers.
Health benefits of taking probiotics
Bacteria have a reputation for causing disease, so the idea of tossing down a few billion a day for your health might seem — literally and figuratively — hard to swallow. But a growing body of scientific evidence suggests that you can treat and even prevent some illnesses with foods and supplements containing certain kinds of live bacteria. Northern Europeans consume a lot of these beneficial microorganisms, called probiotics (from pro and biota, meaning “for life”), because of their tradition of eating foods fermented with bacteria, such as yogurt. Probiotic-laced beverages are also big business in Japan.
Enthusiasm for such foods has lagged in the United States, but interest in probiotic supplements is on the rise. Some digestive disease specialists are recommending them for disorders that frustrate conventional medicine, such as irritable bowel syndrome. Since the mid-1990s, clinical studies have established that probiotic therapy can help treat several gastrointestinal ills, delay the development of allergies in children, and treat and prevent vaginal and urinary infections in women.
Self-dosing with bacteria isn’t as outlandish as it might seem. An estimated 100 trillion microorganisms representing more than 500 different species inhabit every normal, healthy bowel. These microorganisms (or microflora) generally don’t make us sick; most are helpful. Gut-dwelling bacteria keep pathogens (harmful microorganisms) in check, aid digestion and nutrient absorption, and contribute to immune function.
The best case for probiotic therapy has been in the treatment of diarrhea. Controlled trials have shown that Lactobacillus GG can shorten the course of infectious diarrhea in infants and children (but not adults). Although studies are limited and data are inconsistent, two large reviews, taken together, suggest that probiotics reduce antibiotic-associated diarrhea by 60%, when compared with a placebo.
Probiotic is a nondigestible supplement. a dietary supplement in the form onondigestible carbohydrate that fthe growth of desirablemicroflora in the large bowel.
Probiotic is a substance containing beneficial microorganisms: a substance containing live microorganisms that claims to be beneficial to humans and animals, e.g. by restoring the balance of microflora in the digestive tract.
Probiotic therapy may also help people with Crohn’s disease and irritable bowel syndrome. Clinical trial results are mixed, but several small studies suggest that certain probiotics may help maintain remission of ulcerative colitis and prevent relapse of Crohn’s disease and the recurrence of pouchitis (a complication of surgery to treat ulcerative colitis). Because these disorders are so frustrating to treat, many people are giving probiotics a try before all the evidence is in for the particular strains they’re using. More research is needed to find out which strains work best for what conditions.
Probiotics may also be of use in maintaining urogenital health. Like the intestinal tract, the vagina is a finely balanced ecosystem. The dominant Lactobacilli strains normally make it too acidic for harmful microorganisms to survive. But the system can be thrown out of balance by a number of factors, including antibiotics, spermicides, and birth control pills. Probiotic treatment that restores the balance of microflora may be helpful for such common female urogenital problems as bacterial vaginosis, yeast infection, and urinary tract infection.
Many women eat yogurt or insert it into the vagina to treat recurring yeast infections, a “folk” remedy for which medical science offers limited support. Oral and vaginal administration of Lactobacilli may help in the treatment of bacterial vaginosis, although there isn’t enough evidence yet to recommend it over conventional approaches. (Vaginosis must be treated because it creates a risk for pregnancy-related complications and pelvic inflammatory disease.) Probiotic treatment of urinary tract infections is under study.
Probiotics are generally considered safe — they’re already present in a normal digestive system — although there’s a theoretical risk for people with impaired immune function. Be sure the ingredients are clearly marked on the label and familiar to you or your health provider. There’s no way to judge the safety of unidentified mixtures.
In the United States, most probiotics are sold as dietary supplements, which do not undergo the testing and approval process that drugs do. Manufacturers are responsible for making sure they’re safe before they’re marketed and that any claims made on the label are true. But there’s no guarantee that the types of bacteria listed on a label are effective for the condition you’re taking them for. Health benefits are strain-specific, and not all strains are necessarily useful, so you may want to consult a practitioner familiar with probiotics to discuss your options. As always, let your primary care provider know what you’re doing,