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Friday, August 24, 2007In addition, the label would also warn that "UV exposure from the sun increases the risk of skin cancer, premature skin aging and other skin damage. It is important to decrease UV exposure by limiting time in the sun, wearing protective clothing and using a sunscreen." Directions would tell people to reapply sunscreen "at least every 2 hours." The intent of the warning is to alert consumers that sunscreen is only a part of protecting yourself from sun exposure, Holman said. According to the FDA, the proposal has guidelines for testing that manufacturers need to do to support their claims. Under the rule, sunscreens could have a maximum SPF of 50+ unless test data shows that a higher number is warranted. In addition, the definition of SPF would change from "sun protection factor" to "sunburn protection factor." This change will prevent "the impression of solar invincibility and a false sense of security," according to the agency's proposal. The FDA will now require sunscreen labels to tell us how well they protect agains UVA radiation in addition to the UVB protection they already proclaim. Certainly, sunburns and frequent exposure to large amounts of sun are a risk factor for sun cancer. Sun screen is a necessity if, for example, you are spending the day at the beach or on the water, or shirtlessly shingling roofs. However, as always, all things in moderation. The sun and its UVB radiation is important in vitamin D production. This review article ($$$ required for full article) makes a very persuasive case of the importance of vitamin D to the human body: Although there is no consensus on optimal levels of 25-hydroxyvitamin D as measured in serum, vitamin D deficiency is defined by most experts as a 25-hydroxyvitamin D level of less than 20 ng per milliliter (50 nmol per liter)....a level of 25-hydroxyvitamin D of 21 to 29 ng per milliliter (52 to 72 nmol per liter) can be considered to indicate a relative insufficiency of vitamin D, and a level of 30 ng per milliliter or greater can be considered to indicate sufficient vitamin D. With the use of such definitions,it has been estimated that 1 billion people worldwide have vitamin D deficiency or insufficiency. According to several studies, 40 to 100% of U.S. and European elderly men and women still living in the community (not in nursing homes) are deficient in vitamin D. More than 50% of postmenopausal women taking medication for osteoporosis had suboptimal levels of 25-hydroxyvitamin D — below 30 ng per milliliter (75 nmol per liter). Children and young adults are also potentially at high risk for vitamin D deficiency. For example, 52% of Hispanic and black adolescents in a study in Boston and 48% of white preadolescent girls in a study in Maine had 25-hydroxyvitamin D levels below 20 ng per milliliter. In other studies, at the end of the winter, 42% of 15- to 49-year-old black girls and women throughout the United States had 25-hydroxyvitamin D levels below 20 ng per milliliter,25 and 32% of healthy students, physicians, and residents at a Boston hospital were found to be vitamin D–deficient, despite drinking a glass of milk and taking a multivitamin daily and eating salmon at least once a week. In Europe, where very few foods are fortified with vitamin D, children and adults would appear to be at especially high risk. People living near the equator who are exposed to sunlight without sun protection have robust levels of 25-hydroxyvitamin D — above 30 ng per milliliter.27,28 However, even in the sunniest areas, vitamin D deficiency is common when most of the skin is shielded from the sun. In studies in Saudi Arabia, the United Arab Emirates, Australia, Turkey, India, and Lebanon, 30 to 50% of children and adults had 25-hydroxyvitamin D levels under 20 ng per milliliter. Also at risk were pregnant and lactating women who were thought to be immune to vitamin D deficiency since they took a daily prenatal multivitamin containing 400 IU of vitamin D (70% took a prenatal vitamin, 90% ate fish, and 93% drank approximately 2.3 glasses of milk per day); 73% of the women and 80% of their infants were vitamin D–deficient (25-hydroxyvitamin D level, <20 ng per milliliter) at the time of birth. We always think of Vitamin D as being important for bone health, which it is, but it's also an important factor in muscle strength and performance, and it regulates cell growth (which could give it a role in the body's natural defenses against cancer). So how much sun exposure is enough? Sensible sun exposure can provide an adequate amount of vitamin D3, which is stored in body fat and released during the winter, when vitamin D3 cannot be produced. Exposure of arms and legs for 5 to 30 minutes (depending on time of day, season, latitude, and skin pigmentation) between the hours of 10 a.m. and 3 p.m. twice a week is often adequate.... ....exposure to a tanning bed for 30 to 50% of the time recommended for tanning (with sunscreen on the face) is an excellent means of treating and preventing vitamin D deficiency. If the sun is too scary, however, one may take a vitamin D supplement- but again, in moderation. It's possible to overdose on vitamin D. The author of the review article suggests 800-1000 IU a day. I'm not often persuaded by claims for vitamins, but after reading that review, I, too, thought vitamin D seemed the elixir of life. And I started taking a vitamin D tablet every day since I'm slaving away in my office between 10 and 3 every day. UPDATE: One of the comments challentes me to find a fatality from vitamin D overdose. Vitamin D intoxication causes renal failure and elevated calcium levels. Either of those can kill you. The good news is that it's reversible if the cause is recognized and the vitamin D supplements stopped. (See this case.) posted by Sydney on 8/24/2007 08:23:00 AM 7 comments
Wednesday, December 28, 2005High doses of vitamin D can reduce the risk of developing some common cancers by as much as 50%, US scientists claim. ....Taking 1,000 international units (IU) - or 25micrograms - of the vitamin daily could lower an individual's cancer risk by 50% in colon cancer, and by 30% in breast and ovarian cancer, they said. ....Professor Cedric Garland, who led the review study, said: "A preponderance of evidence, from the best observational studies the medical world has to offer...has led to the conclusion that public health action is needed." The usual recommended dose of vitamin D is 400 to 800 IU's a day. And excess of vitamin D can be bad for you. The research (available only in the abstract to the general public) is not the of the strongest sort: A PubMed database search yielded 63 observational studies of vitamin D status in relation to cancer risk, including 30 of colon, 13 of breast, 26 of prostate, and 7 of ovarian cancer, and several that assessed the association of vitamin D receptor genotype with cancer risk. The majority of studies found a protective relationship between sufficient vitamin D status and lower risk of cancer. Whenever researchers couch their results in terms of "risk," rather than absolutes, watch out. They're usually magnifying their results. The magnification is only worse when the study is a compilation of a bunch of other studies that used risk alone. Professor Garland has long had an interest in Vitamin D and its relationship with cancer. He gets quoted by many a tanning salon on the subject. There's nothing wrong with having a special interest for research, or a pet theory, but sometimes it can result in a blind eye to subtle nuance. It can also lead to a tendency to exaggerate the importance of a finding. Should we really promote use of high dose vitamin D for the greater public good? We can't say that based on this study, though Dr. Garland would disagree. posted by Sydney on 12/28/2005 08:50:00 AM 1 comments
Tuesday, May 01, 2007But perhaps the biggest bombshell about vitamin D's effects is about to go off. In June, U.S. researchers will announce the first direct link between cancer prevention and the sunshine vitamin. Their results are nothing short of astounding. A four-year clinical trial involving 1,200 women found those taking the vitamin had about a 60-per-cent reduction in cancer incidence, compared with those who didn't take it, a drop so large — twice the impact on cancer attributed to smoking — it almost looks like a typographical error. And in an era of pricey medical advances, the reduction seems even more remarkable because it was achieved with an over-the-counter supplement costing pennies a day. One of the researchers who made the discovery, professor of medicine Robert Heaney of Creighton University in Nebraska, says vitamin D deficiency is showing up in so many illnesses besides cancer that nearly all disease figures in Canada and the U.S. will need to be re-evaluated. "We don't really know what the status of chronic disease is in the North American population," he said, "until we normalize vitamin D status." We'll need to see the numbers to know how jaw dropping that 60 percent reduction is. However, here's some food thought. Cholesterol is the building block for Vitamin D. And what have we been preaching - and doing - to patients even more emphatically than sun avoidance? Lowering cholesterols to very low levels. It hasn't been studied for long, but so far there's no evidence that cholesterol lowering medications (i.e. statins) cause cancer. (Although there may be a greater risk for the elderly.) posted by Sydney on 5/01/2007 09:00:00 PM 1 comments
Wednesday, April 30, 2003No longer, the experts say, are they concerned about vitamin deficits. Those are almost unheard of today, even with the population eating less than ideal diets and skimping on fruits and vegetables. Instead, the concern is with the dangers of vitamin excess. "There has been a transition from focusing on minimum needs to the reality that today our problem is excess - excess calories and, yes, excesses of vitamins and minerals as well," said Dr. Benjamin Caballero, a member of the Food and Nutrition Board at the National Academy of Sciences and the director of the Center for Human Nutrition at Johns Hopkins University. This is nothing new. They’ve been teaching about vitamin toxicity in medical schools for years. The fat-soluble ones are particularly prone to having toxic effects, because they’re stored in the body fat for later use rather than excreted in the urine, like water soluble vitamins are. Their toxic effects are describe detail here: Vitamin A, Vitamin E, Vitamin D , and Vitamin K. Even Vitamin B6 can cause a toxic neurological disorder. Not only do large amounts of these vitamins cause toxic syndromes, they might actually make worse that which they’re promoted for improving: ...The most popular individual supplements are vitamins C and E, said Dr. Robert M. Russell, the director the Human Nutrition Research Center of Agriculture Department at Tufts University, who is head of the Food and Nutrition Board. Scientists once thought those vitamins could help prevent ailments like cancer and heart disease, but rigorous studies found no such effects. Vitamin E supplements can increase the risk of heart attacks and strokes, and studies of vitamin C supplements consistently failed to show that it had any beneficial effects... ...Several recent large studies indicate that people with high levels of vitamin A in their blood have a greater risk for osteoporosis. People can easily reach a potentially dangerous level, about five times the recommended dose, by taking vitamins and supplements, nutrition researchers say... ....Two large randomized trials of vitamin A and beta carotene that researchers hoped would show a protective value against cancer found no benefit, and one found that participants who took the supplements had more cancer. A large study of vitamin E and heart disease found that it did not prevent heart attacks and that people taking it had more strokes. Another study, of women with heart disease, found that antioxidant vitamins might actually increase the rate of atherosclerosis... ....a European study, reported recently at a meeting of the American College of Cardiology, found that folic acid supplements actually made matters worse for heart disease patients. The study, the Folate After Coronary Intervention Trial, involved 626 patients who were having stents inserted into blocked arteries to keep them open. Half were randomly assigned to take folic acid, and the rest took a placebo. Six months later, the arteries of those taking folic acid were significantly narrower than the arteries of those taking a placebo, exactly the opposite of what the investigators had expected. The article points out that other studies have shown the opposite effect. As one researcher puts it: "Over all, the likely explanation is that there is a neutral effect, and these relatively small trials found opposite findings due to the play of chance.” Exactly. posted by Sydney on 4/30/2003 08:14:00 AM 0 comments
Wednesday, March 26, 2003Meanwhile, the cause is still in doubt: Some confirmed the CDC's report Monday that a previously unrecognized coronavirus, a relative of the viral family responsible for many colds, is present in patients' tissues and body fluids. Others continued to find a member of a different family of viruses, paramyxoviruses, which also cause upper respiratory tract infections. "There is consistent finding of both pathogens in individual patients or of either of the pathogens in other patients," said Dr. Klaus Stohr, a WHO virologist. Leading hypotheses, he said, is that either of the infectious agents causes the disease, or both are present, coincidentally, because they are common viruses. But a third possibility, he said, is that both viruses work together in a previously unrecognized way. That last possibility seems most likely. Two viruses working in synergy. Other Viral News: Researchers think they may have found a link between multiple sclerosis and the Epstein-Barr Virus, the virus that causes infectious mononucleosis: The Harvard researchers wanted to know whether there was a way to demonstrate an association between Epstein-Barr and multiple sclerosis. They reviewed blood samples routinely drawn from US military personnel, identified 83 men and women with definite or probable cases of MS, and compared them with military personnel not diagnosed with the disease. They found that the MS patients had dramatically higher levels of Epstein-Barr antibodies, immune-system cells that target the virus. In fact, some of the patients had 20 times as many of those immune cells as people without MS. The researchers also discovered that those markers of elevated immune-system response were evident in the patients' blood years before they were diagnosed with MS. They can't say for sure why some patients' immune systems churn out a stronger response to Epstein-Barr, although researchers have suggested that people infected with the virus later in life have a more robust immune response. Harvard researchers and MS specialists said the findings do not establish a definite link between the virus and MS; rather, the data provide another valuable path of investigation. In fact, multiple sclerosis has many and varied risk associations: Scientists know that genes influence whether someone develops MS, but the role they have in the disease is not nearly so striking as in other conditions. That has led researchers to investigate what else might be involved. Along with theories about viruses and bacteria, there's the geography factor. MS occurs more frequently the farther someone lives from the equator, where the disease is virtually nonexistent. Scientists theorize that a sunshine deficit, and the resulting dearth of vitamin D, in colder climates might explain the phenomenon. ''There's lots of complexity here,'' said Dr. Patricia O'Looney, director of biomedical research at the National Multiple Sclerosis Society. ''But knowing more about the disease will help us understand the disease more, answer more questions, and perhaps lead to more treatments.'' It is a complex disease. It’s one of those diseases that may take time to manifest itself, and even then its symptoms and signs can come and go, making diagnosis difficult. And our treatment isn’t any better. There’s still a long way to go in understanding it well enough to improve our treatment approach. posted by Sydney on 3/26/2003 09:47:00 AM 0 comments
Monday, August 05, 2002posted by Sydney on 8/05/2002 06:26:00 PM 0 comments
Friday, April 19, 2002"The 40 Nobelists, including a few economists, expressed their fears this way: "By declaring scientifically valuable biomedical research illegal, Senator Brownback's legislation, if it becomes law, would have a chilling effect on all scientific research in the United States" and would "send a strong signal to the next generation of researchers that unfettered and responsible scientific investigation is not welcome in the United States." Who said scientists no longer believe in absolutes? William F. Buckley Jr. once famously wrote that he'd rather be governed by the first 100 names in the Boston phone book than by the Harvard faculty. All things considered, I'd rather have the cloning issue decided, just now, by the first 100 names in the U.S. Senate than all the Nobel laureates in America." I'd even settle for the first 100 names in the Boston phone book. Nobel prize winners are notorious for going dotty after they've won their prizes. Does anyone remember Linus Pauling and Vitamin C? Henninger goes on to make an even better point: "Last week President Bush gave a speech supporting a ban in which he worried about a time when "human beings are grown for spare body parts and children are engineered to custom specifications, and that's not acceptable." In more than a few circles today this is read as almost up-from-the-swamp fundamentalism. One major editorial summed up the postmodernist's dismissal in four words: "The President's Narrow Morality." This is self-assured moral trumping, and any veteran of the policy wars is by now used to how this the game is played. It's been fun, sometimes. But on this one subject--what it will mean to manipulate the basis for human life or to "discard" human embryos--winning by characterizing the opposition as narrow moral bumpkins just isn't going to be good enough. Simply asserting that your opponents don't care about mitigating disease with technology isn't good enough. The cloning issue will remain a political and intellectual mess unless its proponents engage the other side and just this once make a more philosophically rigorous case for opening this door and stepping through." Exactly. posted by Sydney on 4/19/2002 08:28:00 PM 0 comments
Wednesday, October 23, 2002Not surprisingly, the researchers who have invested their life’s work in elevated homcysteine levels and their contribution to heart disease are skeptical, yet their comments to the press underscore frailty of the association of high homocysteine levels with the risk of heart disease: After allowing for other risk factors like high blood pressure and smoking, Dr. Clarke's team found that a person who lowered his homocysteine level 25 percent cut the heart-attack risk 11 percent and the stroke risk 19 percent. "That's still a significant association," said Dr. Paul F. Jacques, chief of nutritional epidemiology for the Human Nutrition Research Center on Aging at Tufts University, part of the Agriculture Department. "It's a modest predictor. But it's all in how you define modest." Is it all that significant to reduce the risk, not the incidence, by 8 percentage points? Not really. By any definition, it’s a modest decrease. Then there’s this: Dr. Stampfer cited a study in the journal of the medical association in August. In it, half of 553 heart patients in Switzerland who had operations to reopen clogged arteries were randomly assigned to receive six months of vitamin B therapy. Those who took the therapy had significantly fewer deaths and heart attacks. In the group that took the vitamins, 2.6 percent had nonfatal heart attacks versus 4.3 percent in the control group. Again, a decrease of what amounts to a little more than one percentage point in incidence isn’t really significant in any sense other than the statistical one. This may seem to be a tempest in a teapot, since homocysteine levels can be altered with diet and with folic acid supplements, but there is a growing movement among cardiologists to use statins, the cholesterol drugs, to treat high homocysteine levels, too. Before that move is made, they’d better make sure there’s a truly clinically significant role for them in heart disease. posted by Sydney on 10/23/2002 09:04:00 AM 0 comments
Saturday, March 16, 2002What I am against is the promotion of alternative therapies without a reasoned evaluation of them. Before you claim, for instance, that acupuncture can cure cancer, you’d better have some good hard evidence for it. I am also against the classification of herbal preparations as dietary supplements precisely because they are pharmacologically active. These are drugs with the same potential for side effects and interactions as any prescription drug, and they should be regulated as such. Buying a drug is not the same as buying a bag of apples or even a multi-vitamin. Their presence on the shelf gives a chilling meaning to the phrase caveat emptor. Waiting until after fatal or near-fatal events occur to investigate them is not good enough. But, then, that's my objection to the FDA and prescription drugs as well, they don't investigate them enough before putting them on the market, either. posted by Sydney on 3/16/2002 11:05:00 PM 0 comments
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