Diet and supplements

Noniu said:

How Much Vitamin D is Enough?
How much vitamin D is enough? Report sets new levels
Megadoses of 'sunshine vitamin' don't prevent disease, may be harmful
Below:
Video

x
Jump to discussion
58 total comments
Discussion

Related


FeaturePics stock
Most people in the U.S. or Canada between the ages of 1 and 70 only need 600 international units of vitamin D a day, a new report finds. That's higher than the target on food labels, but much lower than the 2,000 IUs some scientists recommend.
NBC News and news services
updated 49 minutes ago
Share Print Font:
WASHINGTON — For the past few years vitamin D has been the "it" vitamin, with studies wildly trumpeting the supplement's role in strengthening bones, reducing the risk of some cancers, heart disease, along with fighting autoimmune diseases and diabetes. But long-awaited new dietary guidelines say there's no proof that megadoses of the "sunshine vitamin" prevent cancer, diabetes or other conditions.
While some people will need a bit more vitamin D than they're already getting, some studies suggest that too much could actually cause some kinds of cancer, according to the panel of experts at the prestigious Institute of Medicine, the health arm of the National Academy of Sciences.
"More is not necessarily better," cautioned Dr. Joann Manson of Harvard Medical School, who co-authored the Institute of Medicine's report being released Tuesday.
Health highlights
Sip and sniff? Scientists thwart wine allergies
Sulfites long have been blamed for wine allergies, but new research suggests molecules called glycoproteins might be a bigger culprit.
14 foods that could change a diabetic's life
9 million Tylenol bottles recalled
Airport pat-downs may raise infection risk
Look at this turkey. Do you feel nicer already?
While the panel found powerful evidence that vitamin D — together with calcium — can protect bones, the new report could dampen the national sunshine vitamin fad.
Most people in the U.S. and Canada — from age 1 to age 70 — need to consume no more than 600 international units of vitamin D a day to maintain health, the report found. People in their 70s and older need as much as 800 IUs. The report set those levels as the "recommended dietary allowance" for vitamin D.
That's only a bit higher than the target of 400 IUs set by today's government-mandated food labels, and higher than 1997 recommendations by the Institute of Medicine that ranged from 200 to 600 IUs, depending on age.
Story: Many preventable cancers caught at late stage
But it's far below the 2,000 IUs a day that some scientists recommend, pointing to studies that suggest people with low levels of vitamin D are at increased risk of certain cancers or heart disease.
"This is a stunning disappointment," said Dr. Cedric Garland of the University of California, San Diego, who wasn't part of the institute's study and says the risk of colon cancer in particular could be slashed if people consumed enough vitamin D.
"Have they gone far enough [in raising recommended levels]? In my opinion probably not, but it's a step in the right direction," added prominent vitamin D advocate Dr. Michael Holick of Boston University Medical Center, who said the new guidelines draw needed attention to the vitamin D debate and encourage more food marketers to fortify their products with it.
Vitamin D and calcium go hand in hand, and you need a lifetime of both to build and maintain strong bones. But the two-year study by the Institute of Medicine's panel of experts concluded research into vitamin D's possible roles in other diseases is conflicting. Some studies show no effect, or even signs of harm.
How much should you take?
The amount of vitamin D recommended daily, from food or dietary supplements, in a report Tuesday from the Institute of Medicine:

Ages 1 to 70: 600 international units.

Ages 71 and older: 800 IUs.

Calcium and vitamin D must be taken together to build and maintain strong bones. Here are the recommended daily levels of calcium:

Ages 1 to 3: 700 milligrams.

Ages 4 to 8: 1,000 mg.

Ages 9 to 18: 1,300 mg.

Ages 19 to 70: 1,000 mg — but for women the amount rises to 1,200 mg at age 51.

Ages 71 and older: 1,200 mg.

Source: The Associated Press

A National Cancer Institute study last summer was the latest to report no cancer protection from vitamin D and the possibility of an increased risk of pancreatic cancer in people with the very highest D levels. Super-high doses — above 10,000 IUs a day — are known to cause kidney damage, and Tuesday's report sets 4,000 IUs as an upper daily limit — but not the amount people should strive for.
Vitamin D is the latest supplement to have been heavily touted based on animal studies and observations in humans and failed to live up to expectations during rigorous testing. For example, vitamins C and E, beta carotene and lycopene were believed to prevent cancer or heart disease, but didn't pan out, and sometimes caused harm, when tested.
Stay tuned: To help settle the issue, Manson is heading a government-funded study that's recruiting 20,000 healthy older Americans to test whether taking 2,000 IUs of vitamin D really will lower their risk for heart disease, a stroke or certain cancers.
Story: 8 simple ways to control blood sugar -- and save your life
In the meantime, it's hard to consume 600 IUs of vitamin D from food alone. A cup of D-fortified milk or orange juice has about 100 IUs. The best sources may be fatty fish — some servings of salmon can provide about a day's supply. Other good sources are D-fortified cereals.
But here's the report's big surprise: While some people truly are seriously deficient in vitamin D, the average American in fact already has enough circulating in his or her blood — because we also make vitamin D from sun exposure, and because many people already take multivitamins or other D-containing dietary supplements.
Wait a minute: Headlines in recent years have insisted the opposite, that a majority of people don't get enough vitamin D, especially during the winter. What explains the contradiction?
A relatively inexpensive blood test measures something called 25-hydroxy vitamin D, the active form in the body. Most testing laboratories are using a too-high cutoff for those blood levels, said report co-author Dr. Clifford Rosen of the Maine Medical Center. The report says at least 20 nanograms is adequate for bone health, while many labs instead list people as low if their blood levels are below 30 ng. Serious vitamin D deficiencies are diagnosed when levels dip well below 20, something that hasn't changed.
Most popular
Wis. students kept gunman talking, laughing
NYT: South celebrates Civil War, without slaves
Yemen cable gives al-Qaida new 'recruiting' tool?
Otter attacks teen on camera
Obama, GOP head to the bargaining table
Tension in the Koreas
Rosen called the state of vitamin D testing "the wild, wild West," and said he hoped that "with this report, we can at least temper people's enthusiasm for just taking tons of supplements."
As for calcium, the report recommended already accepted levels to go along with your daily D — about 1,000 milligrams of calcium a day for most adults, 700 to 1,000 mg for young children, and 1,300 mg for teenagers and menopausal women. Too much can cause kidney stones; the report said that risk increases once people pass 2,000 mg a day.
Story: 14 foods that could change a diabetic's life
It's true that most studies link poor health to vitamin D levels that are below 20 ng, said preventive cardiologist Dr. Erin Michos, a Johns Hopkins University School of Medicine professor who wasn't part of the study.
But, "I'm not sure I'm going to dramatically change my practice," said Michos, who pushes her patients to boost their levels until they're between 30 and 50 ng.
And even if future trials show that vitamin D does help protect against other diseases, the amounts required for bone health should be perfectly sufficient, panel members told NBC News.
The Associated Press and NBC's Robert Bazell contributed to this report

No Silver bullet
It is shown that many vitamins and minerals and supplements work together and in varied levels to achieve a far superior effect and more effective absorption and metabolization when taken in the right combination along with many other aspects include NOT eating certain foods which may block or hinder the desired effect. A quick example is Calcium is not absorbed well from dairy sources. The countries with the highest consumption of dairy are also the same ones with the highest incidence of Osteoporosis. Coincidence ??

Isolating a particular Vitamin is not the best way to analyze the effects on health and disease. There far more to the complication way we metabolize foods.

Scam