Food for Thought: Bread and Chocolate, No Longer D-Minimus, Science News Online, May 7, 2005

[Guest guest]

Bread and Chocolate, No Longer D-Minimus

Janet Raloff

Last of a three-part series on the sunshine vitamin

Part I: Season Affects Cancer-Surgery Survival

Part II: Understanding Vitamin D Deficiency

How do you get people to take a big dose of vitamin D? One midwestern

company thinks the answer is to put the sunshine vitamin in bread—and

chocolate. The firm, Natural Ovens Bakery, is responding to growing

concerns about chronic, widespread vitamin D deficiency by pioneering

the robust fortification of new foods.

While milk and some orange juice today carries 100 international units

(IU) of this essential nutrient per 8 ounce serving, and vitamin pills

typically contain up to 400 IU, the small Wisconsin bakery has

developed a whole-grain bread that contains 1,600 IU per slice. The

firm is also about to begin marketing a dark chocolate that contains a

whopping 2,000 IU of vitamin D per piece.

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These new products are about to be marketed as bone-building dietary

supplements that look and taste like ordinary bread and chocolate.

Natural Ovens Bakery

Indeed, both products will have so much vitamin D that they will have

to be marketed as dietary supplements, much as vitamin pills are today,

observes A. Stitt, board chairman of Natural Ovens Bakery.

Stitt justifies such heavy enrichment of his company's products with

findings from new studies, many reported last month at the Experimental

Biology meeting, in San Diego. The company funded one of the studies.

Over the past few years, a scientific consensus has grown that not only

do most people consume far too little vitamin D, but also that the

official recommended daily intake (RDI) for this nutrient is inadequate

(SN: 10/16/04, p. 248). Driving those assessments has been research

linking more and broader benefits to the vitamin, which can come from

the sun, food, or supplements. The nutrient is the pivotal feedstock

for a hormone that protects bones and muscle and appears to stave off

various cancers, autoimmune disorders, diabetes, and gum disease (SN:

10/9/04, p. 232). Most recently, researchers found that ample vitamin D

improved the odds of people surviving lung cancer (see Season Affects

Cancer-Surgery Survival).

Concludes Stitt: When it comes to vitamin D, superfortified foods are

long overdue because " society is already seriously hurting. "

The issue of safety

Many vitamin D experts have been lamenting the fact that the current

recommended safe upper limit for this nutrient is 2,000 IU per day—well

below the 10,000 to 20,000 IU that the skin may naturally generate

while a person sunbathes on a summer day. Although there is growing

consensus within the research community that the 2,000 IU limit should

be raised, and some scientists say the hike should be dramatic, that

change hasn't happened.

As a consequence, major supplement manufacturers have generally steered

clear of offering products that would allow consumers to easily exceed

the 2,000 IU value. Reinhold Vieth of the University of Toronto says he

recently spoke with representatives of some of the supplement makers,

" and they said that although they were converts to the idea [of raising

vitamin-D intake dramatically], their lawyers said they do not want

them to do anything that might incur some risk of litigation. " For

instance, if someone were to develop kidney stones after taking

supplements offering 3,000 IU per day, he or she might allege that the

problem came from the extra calcium absorption made possible by all of

that vitamin D.

In fact, several scientists argue, ample data already exist to indicate

that intakes of several thousand IU daily don't cause injury.

For instance, in a 1991 study, Vieth's team had each of 61 men and

women consume 1,000 or 4,000 IU of vitamin D daily for 2 to 5 months.

The researchers examined all of the participants for excessive urinary

excretion of calcium, a risk factor for kidney stones, and could " not

detect an effect of treatment on urinary-calcium excretion. "

Moreover, Bruce W. Hollis of the Medical University of South Carolina

has been involved in trials in which pregnant and lactating women took

2,000 to 6,000 IU of vitamin D per day. The federal government is

funding the trial that includes pregnant women. In another study,

Vieth's group has administered up to 2,000 IU of vitamin D per day to

362 children 10 to 17 years old. At a meeting of the American Society

of Bone and Mineral Research last October, his team reported that girls

receiving the upper dose in that trial grew more and denser bone than

did girls who got placebo pills. A lower dose of vitamin D in girls

also brought some bone gains, compared with the performance of placebo

pills. Among boys, vitamin D didn't affect bone development. No adverse

effects were seen in any of the children.

That's not to say vitamin D can't be toxic. It just takes really high

doses, says Vieth, pointing to a criminal case on which he consulted.

The incident came to light when a father and son were hospitalized in

Canada with a case of what initially appeared to be gastroenteritis.

After doctors ruled that out, Vieth's lab tested foods that might

underlie the illnesses. They found the culprit in the sugar bowl.

It turns out that the younger man's girlfriend maliciously mixed pure

crystalline vitamin D into the sugar. Over the next few months, both

father and son ingested whopping amounts, Vieth says, " at a dose that

we worked out to be about 1 million IU per teaspoon of sugar. " Not

surprisingly, he adds, the victims ended up with the dubious

distinction of " world-record high levels of vitamin D in their blood. "

However, once the spiked sugar was discovered and removed from the

men's diets, they recovered.

Foreign affairs

By comparison to such figures, 2,000 IU of vitamin D a day seems

innocuous. However, Stitt says, as long as the U.S. government

continues to list 2,000 IU as the safe upper threshold for vitamin D,

it's been hard to get approval for experiments with doses higher than

that in the United States.

So, Stitt financed a trial in Romania, where profound vitamin D and

calcium deficiency are common. Endocrinologist Mocanu of the

University of Medicine and Pharmacy in Iasi recruited 45 men and women

in their 70s. Many suffered from osteomalacia—weak muscles and

calcium-hungry bones—a hallmark of severe vitamin D deficiency.

For a year, each volunteer received a daily 100-gram (3.5 ounce) bread

roll fortified with 5,000 IU of vitamin D and 800 g of calcium. The

volunteers were allowed to eat the roll all at once or nibble on it

throughout the day. Researchers took blood and urine measurements

throughout the trial to scout for any early signs of toxicity, such as

excess calcium in the urine. None emerged.

Instead, Mocanu reported at the Experimental Biology meeting, signs of

vitamin deficiency disappeared in these senior citizens, and their hips

and spines strengthened. For instance, bone density in their hips—a

region especially vulnerable to fractures associated with

osteoporosis—increased 28 percent. In contrast, Stitt notes, " the best

drug, right now, will increase bone density only an average of 3

percent per year. "

At least as importantly, each of the participants ended up with blood

concentrations of vitamin D of at least 75 nanomoles per liter, a level

recently recommended by several expert panels. Many women in the United

States, especially blacks, have blood concentrations no higher than

about 35 nanomoles per liter, well below the concentration necessary

for building strong bones.

Like candy

The bread used in the Mocanu study was baked with a batter that Stitt

expected to deliver 10,000 IU per roll. " One thing we learned in doing

this study, " he observes, " is that we lose 50 percent [of vitamin D]

during baking. " His company is now fine-tuning a recipe to deliver

similarly huge quantities of vitamin D per 70-calorie slice of bread,

along with 136 milligrams of calcium and a host of other vitamins and

minerals.

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The product looks like, smells like, and tastes like dark chocolate

with nuts. However, the label on the treat will read more like that for

a multivitamin pill.

Natural Ovens Bakery

However, if a person wants a sweeter option, Stitt's company is

creating an 80-calorie dark-chocolate almond cluster, each of which

offers 2,000 IU of vitamin D plus 1,000 mg of vitamin C, which is 10

times the RDI; 20 percent of the RDI for calcium; and fully 100 percent

of the RDI for vitamins E, B6, folate, and B12.

Not only will the candy offer this supplemental bounty of nutrients,

Stitt says, but also the natural antioxidants typical of dark

chocolate, which have been linked in several studies to vascular

changes that might reduce heart disease (SN: 3/18/00, p. 188). Even

almonds have been linked to heart health (SN: 11/21/98, p. 328).

The trick, of course, would be to not overindulge—as if the chocolate

clusters were, well, candy.

http://www.sciencenews.org/articles/20050507/food.asp