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Archive for May, 2008

Vitamin D is hot! Here’s how to get it

By Phillip Rhodes
Senior Editor

Cooking Light

Vitamin D is becoming an increasingly important player in a healthful diet. Over the past 10 years, a spate of research has linked it to an impressive and diverse array of potential benefits. In addition to vitamin D’s well-known function of increasing calcium absorption and thereby helping encourage healthy bone growth, it has shown promise in helping to prevent certain cancers, heart disease, diabetes, and osteoarthritis. CookingLight.com: The Calcium Connection

However, while many in the scientific community are excited about its promise, they have yet to agree on how much you need and where to obtain it. Read on to better understand the debate and learn what’s best for you. CookingLight.com: Top Vitamin D recipes

What vitamin D does

Vitamin D is unique in many ways. At the time of its discovery in 1919, vitamins A, B, and C were already identified; D was the next letter in line, so that was the name given to the compound. However, vitamin D behaves like a hormone in the body, relaying chemical messages  something no other vitamin does. For example, vitamin D signals the intestines to absorb calcium from foods and to regulate its uptake by bone cells.

Some nutrients, such as vitamin C, are put to work immediately by the body in the form in which they are consumed. Vitamin D, however, requires processing. Vitamin D begins as a relative of cholesterol. Dehydrocholesterol molecules are stored in your skin, waiting to absorb sunlight. When this occurs, dehydrocholesterol can be transformed into previtamin D3 (cholecalciferol), the most readily absorbed form of vitamin D. Another form, previtamin D2 (ergocalciferol) is derived from plant sources and can only be obtained through diet. Both previtamins are processed by the liver and kidneys into a final form called calcitriol, which then travels to the vitamin D receptors that exist in almost all, if not all, cells in your body.

“Vitamin D is a key component in helping the body respond to many different kinds of assaults and stimuli,” says Robert Heaney, Ph.D., professor of medicine at Creighton University in Omaha, Nebraska. “In the absence of it, you’re asking the body to defend itself with one hand tied behind its back.”

Most of the good news about vitamin D comes thanks to improved methods of measuring the levels of vitamin D in the body. “We didn’t have a good way to measure vitamin D until 15 years ago, and the test took five to 10 years to reach widespread use,” Heaney says. “Previously, the only indicator of vitamin D deficiency was rickets [a disease resulting in softened bones].”

How much do you need?

The Institute of Medicine, a group that uses scientific research to formulate public health policies, currently recommends an Adequate Intake, or AI, rather than a specific daily amount of vitamin D. The AI for vitamin D is 200 International Units for adults under age 50, 400 IU for those 51 to 70, and 600 IU for those age 71 and above. As new studies continue to showcase vitamin D’s potential benefits, more scientists are calling for increased recommendations. Some suggest as much as 10,000 IU –currently the tolerable upper intake daily. CookingLight.com: Vitamin D ranks among the nutrients women need most

Late last year, a group of leading scientists published an editorial in the American Journal of Clinical Nutrition calling for an “urgent need” to increase the AI for vitamin D. Among them was Walter Willett, M.D., the widely respected chairperson of the Harvard School of Public Health’s department of nutrition. “The range we are talking about — 1,000 IU per day –is still a small dose,” Willett says. (Consider this: A fair-skinned person can manufacture 15,000 IU or more of vitamin D in as little as 30 minutes of optimal sun exposure.)

In response to the debate, the National Institutes of Health’s Office of Dietary Supplements last year began an intensive effort to learn more about vitamin D, partnering with other federal agencies to assemble a panel to assess research needs and priorities. Their efforts may result in a new AI when the Dietary Guidelines for Americans are revised in 2010.

“Scientists agree that as the DRIs are revisited, vitamin D is one of the first recommendations that should be reconsidered,” says Patsy M. Brannon, Ph.D., professor of nutrition at Cornell University who coordinates the ODS’ vitamin D initiative. “The current recommendation is a decade old. There’s been a lot of research in the last 10 years. Whether there is sufficient strength of evidence to increase recommendations is where scientists disagree.”

Until they reach a consensus, you have three options for obtaining vitamin D: food, sunlight, or supplements.

Source 1: Food

Foods naturally rich in vitamin D are scarce. Seafood options top the list  cod liver oil, salmon, mackerel and tuna. (Bonus: they also contain heart-healthy omega-3 fatty acids.) After that, fortified foods help fill the gap. Milk is fortified with 100 IU per 8-ounce serving. Some yogurts and cheeses also contain vitamin D, as do breakfast cereals and juices. CookingLight.com: Read more about where to find vitamin D in food

Source 2: Sunlight

Every time sunlight warms our skin, your body produces vitamin D. However, sunlight is unreliable and several factors influence its ability to induce vitamin D production, including: the angle of the sun, the latitude in which you live, you skin pigmentation, age, and use of skin-care products containing sun-protection factor (SPF). Also, there’s the not-small matter of skin cancer risk, which is heightened by exposure to sunlight. CookingLight.com: Learn more about safely absorbing vitamin D from sunlight

Source 3: Supplements

Supplements are a reliable and safe source of vitamin D. The key is buying the right type of supplement. Most multivitamins are fortified with the current AI for vitamin D; 400 IU. Check the label to make sure the vitamin you choose is made with the D3 form (it may be listed as cholecalciferol) CookingLight.com: Find out how to obtain just the right amount for you

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Obama takes super-delegate lead

Barack Obama on the campaign trail in Oregon - 10/5/2008

Barack Obama now has a slim lead in super-delegate

Democratic presidential candidate Barack Obama has overtaken his rival Hillary Clinton for the first time in endorsements from super-delegates.

Four super-delegates – party and elected officials – pledged to support Mr Obama, including two who previously supported Mrs Clinton.

Mr Obama also has a strong lead in delegates won in state primary and caucus votes.

The Democratic super-delegates look set to decide who wins the nomination.

Added to the nine who came out in support of Barack Obama on Friday, he now has 275 super-delegates to Mrs Clinton’s 271.

‘Likely nominee’

Mr Obama won a convincing victory in Tuesday’s North Carolina primary; while Mrs Clinton narrowly won in Indiana.

Six more states hold primaries before the Democratic Party officially declares at its nominating convention in August who will take on presumptive Republican candidate John McCain.

Hillary Clinton in New York - 10/5/2008

Both candidates have promised to support party unity no matter who wins

The nearly 800 super-delegates automatically attend the Denver convention and can vote for whomever they choose.

Mrs Clinton held a massive lead in super-delegate support before the party’s first primary in Iowa in January.

But a string of wins for Mr Obama has convinced many of them to come out in his favour.

Unity stressed

On Friday, former Democratic US presidential hopeful John Edwards said that Mr Obama is now the party’s “likely presidential nominee”.

But he stopped short of actually endorsing Mr Obama.

With fears mounting that the long, indecisive campaign may be fatally dividing the party, both candidates have been careful to say that they will work to unify Democrats before November’s election.

“I want to go into the general election… with the party unified and ready to take on what I think is a wrong-headed vision of where the country should go,” said Mr Obama from Bend, Oregon.

Although Mrs Clinton has said the nominating race is not over, she also said Democrats would come together against the Republicans no matter who wins.

“What I hear and what I see is all about how we’re going to finish this nominating contest which we will do,” she said at a New York fund-raiser.

“Then we will have a nominee, and we will have a unified democratic party, and we will stand together and we will defeat John McCain in November and go on to the White House.”

Mrs Clinton is favoured to win the next primary in West Virginia on Tuesday. Then Oregon and Kentucky vote on 20 May.