Vitamin D yet again

[Guest guest]

According to this article salmon does not contain Vit D. This is contrary

to other sources that we've posted here. Does anyone know what the correct

scoop on Vit D and fish (especially salmon) is???

A Deficiency of D?

By Sally Squires

A new national study finds that most adults, especially those over 50,

fall short on recommended daily levels of vitamin D, an essential nutrient

long known to preserve bones and now increasingly tied to protection against

ailments from cancer to rheumatoid arthritis.

And no, just drinking more vitamin-D fortified milk or juice may not make

up the deficit, many experts say, although it can help. Spending 10 to 15

minutes in the sun, done with proper care, might.

The study is based on data drawn from a large, federally funded national

health survey and analyzed by a team of scientists from Boston University

and private industry. Presented yesterday at the Experimental Biology annual

meeting in San Diego, the study found that vitamin D intakes peak during

childhood and teenage years and then decline.

Women ages 19 to 50, as well as men and women 51 and older, ate the least

food rich in vitamin D. Even when the team accounted for use of vitamin D

dietary supplements, few older men and women reached recommended daily

levels. The researchers concluded that the low intakes, especially for the

aged, " warrant intervention. "

At a time when researchers are discovering a widening role for vitamin D,

" many lines of investigation indicate that most Americans do not have

optimal levels of vitamin D, mainly because of low sunlight exposure, " said

Walter Willett, chairman of the Department of Nutrition at the Harvard

School of Public Health in Boston. Willett convened a meeting in January

with leading vitamin D researchers and vitamin manufacturers to review the

latest findings. Since there are limited food sources of vitamin D, " the

most practical way to increase our vitamin D levels is from supplements, "

Willett said.

Unlike other essential nutrients, vitamin D is made by the skin, which

requires ultraviolet light to produce the vitamin from cholesterol. Those in

the Washington area and others who live north of Newport News, Va., often

don't get enough sun exposure year round to make sufficient vitamin D.

Concern over skin cancer means that more people are wearing sunblocks,

which inhibit production of vitamin D. Dark-skinned people have to spend up

to a couple of hours in the sun to make enough vitamin D. Light-skinned

people can get what they need in about 10 to 15 minutes.

The skin's ability to make vitamin D declines significantly with age. For

this reason, the National Academy of Sciences (NAS) set the latest vitamin D

daily intake on an age-related scale: 200 International Units (IU) --

about the amount found in two eight-ounce glasses of milk -- for those 19

to 50 years of age; 400 IU for those aged 51 to 70 years; and 600 IU for

people 70 and older. The NAS also set a tolerable upper intake of 2,000 IU

for adults. Toxic levels have been reported at 10,000 IU or higher per day.

But a growing number of scientists believe that vitamin D intake should be

at least 1,000 IU or higher.

" Fifty years ago, a bunch of guys got in a room and said, 'We know that a

teaspoon of cod liver oil cures rickets in a child and it has 400 IU of

vitamin D,' " said Bruce Hollis, a professor of pediatrics, biochemistry and

molecular biology at the Medical University of South Carolina. " They

transposed that amount onto adults. It was arbitrarily set with no evidence

[in adults] at all. "

Where research once suggested a limited health role for vitamin D, today

there is increasing evidence that it protects against breast, colon and

prostate cancer. Population studies show that people with the highest

vitamin D levels are less likely to develop multiple sclerosis, lupus,

rheumatoid arthritis and other autoimmune diseases than those with lower

levels. Plus it appears that vitamin D may protect against heart disease,

type 2 diabetes and the insulin resistance that precedes it.

" If just half the chronic diseases laid at the feet of vitamin D pan out,

it will be quite significant, " said P. Heaney, a professor of

medicine at Creighton University in Omaha and a proponent for increasing

vitamin D intake.

Just a decade ago, scientists developed an inexpensive blood test that more

accurately determines vitamin D status. Use of that test revealed widespread

deficiencies and led the NAS to note in 1997 that vitamin D " deficiency is

now a significant concern in adults over the age of 50 years who live in the

northern industrialized cities of the world. "

In 2004, the dietary guidelines scientific committee concluded the elderly,

people with dark skin and those exposed to insufficient sunlight " are at

risk of being unable to maintain vitamin D status " and may " need

substantially more than " the 1997 recommendations called for.

But some doctors worry that the evidence is still preliminary. Few if any

studies " show that people are having problems with the lower limits of

vitamin D being where they are, " said New York University dermatologist

Darrel Rigel, a past president of the American Academy of Dermatology.

Dermatologists are particularly concerned that raising the vitamin D

recommendation might tempt some people to spend more time in the sun or in

tanning booths, thus increasing their risk of skin cancer. " Our

recommendation is to take either vitamin pills or eat food that we know has

higher levels of vitamin D, " rather than increase sun exposure, said Henry

Lim, chairman of dermatology at the Henry Ford Hospital in Detroit.

Here's how to boost vitamin D levels safely:

Drink vitamin D fortified beverages. While diet alone is unlikely to get

you to the levels needed, drinking milk and other vitamin D fortified

beverages will help. Some juice and soy milk is also fortified. An 8-ounce

glass of any of these beverages delivers about 100 IU, or about half the

intake recommended daily for adults 19 to 50 years of age; a quarter of the

amount for adults 51 to 70; and just a sixth of the intake for those 70 and

older. Yogurt and cheese are not fortified with vitamin D.

Eat more herring and sardines. An ounce of pickled herring has nearly

200 IU of vitamin D. Two small sardines have 65 IU. But not all fish

contains vitamin D. Salmon and tuna, for example, have none.

Breakfast on fortified cereal or cereal bars. A cup of vitamin D

fortified cereal delivers about 40 to 60 IU of vitamin D. Fortified cereal

bars have even less: about 30 IU per bar.

Take a multivitamin or other supplement. Most multivitamins, even the

ones aimed at seniors, provide 400 IU of vitamin D, which won't cover those

70 and older. Some vitamin and health food stores sell gelcaps of vitamin D

supplements that range from 700 IU to 2,000 IU. " The most practical way to

increase our vitamin D levels is from supplements, " said Harvard's Willett.

Fun in the sun. Fifteen minutes of peak sun exposure without sunscreen

allows a light-skinned person to make about 20,000 IU of vitamin D,

according to Hollis. But much of that dose quickly " goes away, " he said.

You'd need such exposures at least every few days in order to sustain

adequate levels. Since regular sun exposure increases skin cancer risk,

" it's okay to expose yourself a little to the sun, " said Henry Ford's Lim,

" but not too much. " •