Have a D-ficiency? Here are facts on vitamin D

A campaign last year encouraging people to soak up some sun or slip into a tanning bed to prevent a vitamin D deficiency created all kinds of confusion for a generation used to slathering on sunscreen.
On one hand, skipping a sunscreen and getting burned could put them at risk for skin cancer. On the other, using a sun block could mean they would not be getting enough vitamin D.
To shed some light on the vitamin debate, here are the facts, along with some expert advice on whether to rely on sunshine or a supplement for a daily dose of D.
Vitamin D basics
Vitamin D is fat-soluble. People get most of their vitamin D from exposure to sunlight and a few foods. The vitamin promotes the absorption of calcium and helps strengthen bones. There’s growing evidence that many people — by some estimates 60 percent or more — don’t get enough vitamin D.
Supplements vs. sunlight
A little exposure to sunlight — 10 to 15 minutes a week — is enough to supply children and young adults with all the vitamin D they need.
The trick is to not overdo it.
It’s one thing to let children play outdoors without a sunscreen for 15 minutes and another to let them go all day without protection, said Jo Ann Carson, professor of clinical nutrition at UT Southwestern Medical Center.
Parents who tend to forget to slather sunscreen on the kids would be better off giving them a vitamin D supplement rather than risk them getting too much sun exposure, she said.
Besides, going out much longer in the sun than the recommended 15 minutes has no additional benefits because the body won’t absorb it.
The rules change as people age. After age 50, the skin loses its ability to absorb vitamin D from sunlight. By 70, forget about the sun and take a supplement.
Foods rich in vitamin D
Salmon tops the list of foods rich in vitamin D, followed by low-fat milk. Margarine, eggs, beef liver and Swiss cheese also contain small amounts of the vitamin, according to the National Institutes of Health.
How much is enough?
For those 50 and younger, 200 International Units (IU) per day, the equivalent of two glasses of milk, is adequate. For those 51-70, the recommendation is 400 IU, and over 70 it’s 600 IU, according to the National Institutes of Health. But some researchers suggest 1,000 to 5,000 IU a day is safe.
Not enough D
A vitamin D deficiency can lead to rickets and weak muscles. In recent years, several studies have linked a lack of vitamin D with cardiovascular disease, high blood pressure, diabetes and high triglycerides. There’s also evidence that a lack of D is linked to certain cancers and immune dysfunction.
One study published in the American Journal of Clinical Nutrition found that taking 1,000 IU of vitamin D daily reduced the risk of getting cancer.
Too much D
Supplements with calcium and vitamin D can increase the risk of kidney stones. More than 2,000 IU is not recommended. Studies have indicated that doses of up to 10,000 IU per day are not toxic but are not recommended. Taking too much can cause nausea, poor appetite, weakness, weight loss and confusion.
Who’s at risk for a vitamin D deficiency?
Breastfed infant — Human milk does not provide adequate vitamin D.
Older adults — Their skin has difficulty synthesizing vitamin D
People with limited exposure — Those who live in northern latitudes and women who wear long robes and head coverings for religious reasons don’t get enough exposure to sunlight.
People with darker skin — They have greater amounts of melanin, which reduces the skin’s ability to produce vitamin D from sunlight.
Obese people — Their fat cells extract vitamin D from blood and hoard it.
Sources: Harvard Public Health Review, The National Institutes of Health, Food and Drug Administration, Vitamin D Council, NetWellness

'Guardian angel' protein packs punch in fight against cancer

WASHINGTON — It's a tiny molecule with a nondescript name — "p53" — but it has an awesome responsibility: preventing more than half of all human cancers.

Some scientists call it the "guardian angel," "guardian of the genome," or the "dictator of life and death."

P53 is a protein, a string of 393 chemical units stored in the DNA of most of the body's cells. Normally, p53 works to suppress malignant tumors. When it's missing or mutated, however, it can't carry out its lifesaving mission and lets cancerous cells run amok.

Scientists are developing drugs to repair or restore damaged p53 in mice, but so far none of those drugs are ready to treat human cancers.

Almost 50,000 papers about p53 have been published in scientific journals, but its workings are still not fully understood, and it's little known outside the worlds of biology and medicine.

P53 is "certainly the most studied protein in the whole history of cancer," Magali Olivier , an expert at the World Health Organization's International Agency for Research on Cancer in Lyons, France , wrote in the journal Cancer Gene Therapy this fall.

Arnold Levine , a cancer expert at the Institute for Advanced Study in Princeton, N.J. , who discovered p53 almost 30 years ago, said "We have uncovered and explored a process central to life — how a cell responds to stress or perturbation in its environment."

Here's how it works: A normal p53 protein detects a patch of DNA in the nucleus of a cell that has been damaged by accident, a virus, radiation, smoking or other environmental assaults, raising the chance that the cell will turn cancerous. P53 triggers a complex biochemical program that stops the pre-cancerous cell from dividing until it repairs its DNA or commits suicide.

When p53 itself is flawed, however, it allows other cancer-causing genes (known as oncogenes) to hijack the cell's control machinery and set it free to spread wildly — the hallmark of cancer.

"Loss of p53 function in cells leads to uncontrolled proliferation and promotes cancer development," Olivier wrote in a summary of recent p53 research.

The gene that carries the instructions to make p53 is called TP53. Mutations in the gene may be inherited, which is why some cancers run in families.

TP53 is "the most mutated gene in human cancer, and these mutations are correlated with more than 50 percent of all human cancer," said Ronen Marmorstein , an expert on gene regulation at the Wistar Institute in West Philadelphia, Pa.

According to Gerard Evan , a researcher at the University of California's Comprehensive Cancer Center in San Francisco , p53 mutations are also associated with more aggressive cancers, resistance to treatment by radiation and chemotherapy, and decreased patient survival.

Despite the vast amount of research, work is only beginning on cancer therapies based on fixing damaged p53.

Nevertheless, hopes are rising that the immense body of knowledge about p53 will lead to better ways to diagnose, prevent and treat cancer.

"The growing number of p53-targeting strategies raises hope for more efficient cancer therapies in the future," reported Swedish researcher Klas Wiman in the journal Cell Death and Differentiation.

In an experiment in his San Francisco lab, for example, Evan restored damaged p53 in mice suffering from lymphoma.

"The tumors were completely dead within hours." Evan said. "This result is very good news to the many of us who are thinking about trying to restore p53 function in established human cancers."

Unfortunately, restoring p53 may cause accelerated aging, at least in mouse experiments.

"Cancer and senescence may be seen as two alternative fates in aging organisms, the secret of longevity being to find the best possible trade-off between these two options," Olivier reported.

Many questions remain about the workings of p53.

"Complete understanding still remains elusive," Antony Braithwaite , a New Zealand researcher, wrote in Cell Death and Differentiation. "How p53 makes decisions to do one thing or another, or turn on one gene or another, is far from clear."

To accomplish its job, p53 has scan three billion letters in the human genetic code to decide which genes it's going to activate or repress. "This is a tall order," Braithwaite wrote.

ON THE WEB:

For more information on p53

To see Cancer Gene Therapy's summary of recent p53 research

Disco tune "Stayin' Alive" could save your life

WASHINGTON (Reuters) - U.S. doctors have found the Bee Gees 1977 disco anthem "Stayin' Alive" provides an ideal beat to follow while performing chest compressions as part of CPR on a heart attack victim.

The American Heart Association calls for chest compressions to be given at a rate of 100 per minute in cardiopulmonary resuscitation (CPR). "Stayin' Alive" almost perfectly matches that, with 103 beats per minute.

CPR is a lifesaving technique involving chest compressions alone or with mouth-to-mouth rescue breathing. It is used in emergencies such as cardiac arrest in which a person's breathing or heartbeat has stopped.

CPR can triple survival rates, but some people are reluctant to do it in part because they are unsure about the proper rhythm for chest compressions. But research has shown many people do chest compressions too slowly during CPR.

In a small study headed by Dr. David Matlock of the University of Illinois College of Medicine at Peoria, listening to "Stayin' Alive" helped 15 doctors and medical students to perform chest compressions on dummies at the proper speed.

Five weeks after practicing with the music playing, they were asked to perform CPR again on dummies by keeping the song in their minds, and again they kept up a good pace.

"The theme 'Stayin' Alive' is very appropriate for the situation," Matlock said in a telephone interview on Thursday. "Everybody's heard it at some point in their life. People know the song and can keep it in their head."

The findings will be presented this month at a meeting of the American College of Emergency Physicians in Chicago.

Gene discovery may help hunt for blindness cure

LONDON (Reuters) - Scientists have discovered a gene mutation linked to the most common cause of blindness in the developed world, holding out the prospect of better treatments and perhaps eventually a cure.

British scientists said on Tuesday they had found six variants within the gene called Serping1 that were associated with age-related macular degeneration (AMD).

"Our findings add to the growing understanding of the genetics of age-related macular degeneration, which should ultimately lead to novel treatments for this common and devastating disease," Sarah Ennis and Andrew Lotery of the University of Southampton reported in the Lancet journal.

AMD -- which involves damage to the delicate cells of the macula, a region at the center of the retina -- is increasingly common as people get older.

Around 90 percent of patients diagnosed with AMD have the so-called dry version, for which no treatment is currently available.

The rest have wet AMD, which occurs when tiny new blood vessels grow between the retina and the back of the eye. This form of the disease can be treated with modern drugs.

Some cereals more than half sugar: report

WASHINGTON (Reuters) - Some breakfast cereals marketed to U.S. children are more than half sugar by weight and many get only fair scores on nutritional value, Consumer Reports said on Wednesday.

A serving of 11 popular cereals, including Kellogg's Honey Smacks, carries as much sugar as a glazed doughnut, the consumer group found.

And some brands have more sugar and sodium when formulated for the U.S. market than the same brands have when sold in other countries.

Post Golden Crisp made by Kraft Foods Inc and Kellogg's Honey Smacks are more than 50 percent sugar by weight, the group said, while nine brands are at least 40 percent sugar.

The most healthful brands are Cheerios with three grams of fiber per serving and one gram of sugar, Kix and Honey Nut Cheerios, all made by General Mills, and Life, made by Pepsico Inc's Quaker Oats unit.

"Be sure to read the product labels, and choose cereals that are high in fiber and low in sugar and sodium," Gayle Williams, deputy editor of Consumer Reports Health, said in a statement.

Honey Smacks has 15 grams of sugar and just one gram of fiber per serving while Kellogg's Corn Pops has 12 grams of sugar and no fiber.

Consumer Reports studied how 91 children aged 6 to 16 poured their cereal and found they served themselves about 50 to 65 percent more on average than the suggested serving size for three of the four tested cereals.

Consumers International, which publishes Consumer Reports, said it would ask the World Health Organization to develop international guidelines restricting advertising and marketing of foods high in sugar, fat or sodium to children.

However, the group noted that breakfast cereal can be a healthful meal and said adults and children alike who eat breakfast have better overall nutrition, fewer weight problems, and better cognitive performance throughout the day.

Kellogg said it was working to make its food more nutritious.

"Kellogg recently reformulated a number of our cereals including Froot Loops, Corn Pops, Rice Krispies, Cocoa Krispies and Apple Jacks in the U.S. with improved nutritional profiles," a company spokeswoman said by e-mail.

"To put Consumer Reports' information in perspective, yogurt contains more sugar and sodium than a serving of Honey Smacks cereal (25 grams of sugar vs. 15 grams of sugar in Honey Smacks)."

Consumer Reports, like other groups, compares the sugar content of food with its fiber, mineral and vitamin content. Many cereals are fortified with vitamins and minerals.

Glucosamine and chondroitin don't slow arthritis

Two hugely popular supplements used to fight arthritis and joint pain, glucosamine and chondroitin sulfate, do not seem to work any better than placebo to slow the loss of knee cartilage in osteoarthritis, researchers reported on Monday.

But the researchers said some of their findings were confusing and said more study was needed.

"At two years, no treatment showed what we determined to be a clinically important reduction in joint space width loss," said Dr. Allen Sawitzke of the University of Utah School of Medicine, who helped lead the study.

The study, funded by the National Center for Complementary and Alternative Medicine at the National Institutes of Health, confirms other findings showing the supplements have few or no effects.

The trial is called glucosamine/chondroitin arthritis intervention trial or GAIT. Writing in the October issue of Arthritis & Rheumatism, Sawitzke and colleagues said they had trouble interpreting their results because patients who took placebos had a smaller loss of cartilage than they should have.

The original GAIT study results in 2006 found the supplements did not reduce the pain of knee arthritis, except among a small group of patients with moderate to severe pain.

The GAIT researchers continued to watch 572 volunteers for another 18 months and found the supplements did not appear to slow the loss of cartilage, taken either alone or together.

They said arthritis worsened in 24 percent of participants taking both, similar to those taking placebo.

"Research continues to reveal that osteoarthritis, the most common form of arthritis, appears to be the result of an array of factors including age, gender, genetics, obesity, and joint injuries," said Dr. Stephen Katz, director of the NIH's National Institute of Arthritis and Musculoskeletal and Skin Diseases.

"Because osteoarthritis affects nearly 21 million Americans, we are seeking ways to not only treat pain, but also address the structural effects of the condition," he said.

Doctors say leg pain can signal deadly blood clot

WASHINGTON - Far too many Americans are dying of dangerous blood clots that can masquerade as simple leg pain, says a major new government effort to get both patients and their doctors to recognize the emergency in time.

"It's a silent killer. It's hard to diagnose," said acting Surgeon General Dr. Steven Galson, who announced the new campaign Monday. "I don't think most people understand that this is a serious medical problem or what can be done to prevent it."

At issue are clots with cumbersome names: A deep vein thrombosis, or DVT, forms in large veins, usually a leg or the groin. It can quickly kill if it moves up to the lungs, where it goes by the name pulmonary embolism, or PE.

These clots make headlines every few years when seemingly healthy people collapse after long airplane flights or being in similarly cramped quarters. Vice President Cheney suffered one after a long trip last year. NBC correspondent David Bloom died of one in 2003 after spending days inside a tank while covering the invasion of Iraq.

But that provides a skewed vision of the problem. While there aren't good statistics, the new surgeon general's campaign estimates that every year, between 350,000 and 600,000 Americans get one of these clots — and at least 100,000 of them die.

There are a host of risk factors and triggers: Recent surgery or a broken bone; a fall or car crash; pregnancy or taking birth control pills or menopause hormones; being immobile for long periods. The risk rises with age, especially over 65, and among people who smoke or are obese.

And some people have genetic conditions that cause no other symptoms but increase their risk, making it vital to tell your doctor if a relative has ever suffered a blood clot.

People with those factors should have "a very low threshold" for calling a doctor or even going to the emergency room if they have symptoms of a clot, said Galson, who issued a "call to action" for better education of both consumers and doctors, plus more research.

Symptoms include swelling; pain, especially in the calf; or a warm spot or red or discolored skin on the leg; shortness of breath or pain when breathing deeply.

But here's the rub: Doctors are ill-informed, too. For example, studies suggest a third of patients who need protective blood thinners when they enter the hospital for major surgery don't get them. And patients can even be turned away despite telltale symptoms, like happened to Le Keisha Ruffin just weeks after the birth of her daughter, Caitlyn.

Ruffin made repeated visits to doctors and emergency rooms for growing pain in her leg and groin in December 2003 and January 2004, but was told it must be her healing Caesarean section scar.

Finally one night, Ruffin's husband ran her a really hot bath for pain relief — only to have her climb out minutes later with her leg swollen three to four times its normal size, and then pass out.

"I like to call that my miracle bath," Ruffin said, because the sudden swelling proved the tip-off for doctors.

Pieces of a giant clot in her right leg had broken off and floated to her lung. The ER doctor "said if I hadn't made it in when I did, I may not have lived through the rest of the night," recalled Ruffin, now 32, who spent a month in the hospital and required extensive physical therapy to walk normally again.

These clots "tend to fall through the cracks" because they cross so many areas of medicine, said Dr. Samuel Goldhaber, chairman of the Venous Disease Coalition and a cardiologist at Boston's Brigham & Women's Hospital.

With the surgeon general's campaign, "DVT after all these years will finally get the national spotlight like cigarette smoking did in the mid-60s," he said.

In addition to Galson's report:

_The Agency for Healthcare Research and Quality is issuing a 12-page booklet to help consumers tell if they're at risk for DVTs and what to do — and a 60-page DVT treatment-and-prevention guide for doctors and hospitals.

_As a prevention incentive, starting Oct. 1 Medicare will withhold payment from hospitals when patients develop the clots after knee- or hip-replacement surgery.

___

On the Net:

Surgeon General: http://www.surgeongeneral.gov

Venous Disease Coalition: http://www.venousdiseasecoalition.org

Coalition to Prevent DVT: http://www.preventdvt.org