DAILY VITAMIN: IS IT REALLY NECESSARY?

A multivitamin with the morning’s calcium-fortified orange juice. A couple of vitamin C tablets to fend off that cold that’s going around. A power bar for the commute into work, a sandwich with vitamin-fortified bread, a chewy caramel chock-full of calcium.

Before you know it, you’ve dosed yourself with five, six, maybe 10 times the recommended allowance for the day’s nutrients.

“For years, dietitians have been saying, take a vitamin pill for insurance,” says Chris Rosenbloom, professor of nutrition in the college of health and human sciences at Georgia State University. “But people are eating so many fortified foods now, I’m not sure it’s still necessary.”

She’s not sure, because nobody is sure. Nearly 40% of Americans take supplements regularly, half of them taking a vitamin and mineral product, according to the Centers for Disease Control and Prevention, making supplements a $1.3-billion to $1.7-billion a year industry.

Yet despite an ever-proliferating array of supplements on store shelves, along with nutritionists’ almost motherly urging to take them just to be on the safe side, there’s little science to support America’s love affair with vitamins.

Studies showing how well the body absorbs all those compounds sprinkled into Americans’ cornucopia of fortified foods simply don’t exist. And when a panel of experts with the National Institutes of Health examined studies of multivitamins last spring, they concluded that any evidence of their health benefit was thin, and that clinical trials were too short to determine any long-term effects.

“Essentially, if you don’t take multivitamins, there’s no reason to start,” says Dr. J. Michael McGinnis, senior scholar at the Institute of Medicine and chair of the NIH state-of-the-science panel on the role of multivitamins. “If you do, there’s no evidence to stop.”

Adds Dr. Charles Halsted, editor of the American Journal of Clinical Nutrition: “You’re deluding yourself if you think you’re preventing a heart attack or cancer with a multivitamin. It’s a waste of money if you’re perfectly healthy and have a proper diet.”

Those are fighting words for many believers -- and, indeed, the discussion can turn into a war of dueling studies, with defenders dragging out ones suggesting heart benefits or cancer prevention properties and skeptics citing others in which bright vitamin hopes have been dashed. “People sort of cherry-pick studies that they like,” says Alice Lichtenstein, professor of nutrition science and policy at Tufts University. “You can find a study that supports almost anything.”

Such conflicting studies fuel debates over high doses of specific vitamins, but few experts get rankled over the lowly multivitamin. After all, those who believe in vitamins point out that no one is at risk of overdosing by taking such a pill, even on top of fortified foods.

And, in fact, most nutrition experts -- and probably primary care doctors -- continue to say that taking a daily multivitamin pill is a sensible backup plan for the days people don’t get all their fruits and vegetables, milk, cheese or yogurt, whole grain breads and cereals or meat, chicken, fish and legumes.

“I think all Americans -- adults, teenagers and children -- should be taking a multivitamin. Period,” says Jeffrey Blumberg, professor of nutrition and director of the Antioxidants Research Laboratory at Tufts University.

Still, many in public health worry that a recommendation for a pill might signal to people that actual food isn’t important.

“Does it suggest that, with a vitamin pill, you’ve got an insurance policy, and you don’t need to be concerned about your diet?” asks Lichtenstein. Without convincing evidence to suggest benefit from a daily multivitamin, that’s the wrong message.

Both camps agree, however, that significant problems come not with a basic multivitamin, which typically covers 100% of the recommended intake of the 13 compounds classified as vitamins and an assortment of minerals, but when people start thinking that if a little is good, a lot is better -- and ramp up their intake of a vitamin far past recommended levels.

“We’re seeing a dose creep in the population,” says McGinnis. “And in some cases, many, many-fold above the RDA.”

Mixed messages

You can’t blame people for being confused. Every week, it seems, some study appears in the literature raising a new vitamin hope or dashing an old one.

A sampling of the ping-ponging: A July 2005, study of almost 40,000 women that found that vitamin E supplements did not prevent heart disease and stroke in most women -- though they might provide some protection after age 65. The study also threw cold water on hopes that E could ward off cancer.

On the plus side, a 2005 study reported that vitamin E, along with vitamin C, beta carotene and zinc, helped ward off macular degeneration, the leading cause of vision loss in the elderly.

The hope that lowering homocysteine in the blood by taking B vitamins would reduce the risk of heart attack and stroke was dampened in March when a study found that B’s did lower homocysteine but didn’t reduce heart disease rates.

The compound scientists seem most excited about these days is vitamin D, the so-called sunshine vitamin. Once thought of as merely a defense against rickets, it’s now known to improve the absorption of calcium, aiding bone health. But studies also suggest it can lower the risk of colon, breast, pancreatic and ovarian cancer, and more.

There is ample profit in all this vitamin confusion, with entire grocery aisles dedicated to specialty vitamins for kids, seniors, men or women who believe, at a minimum, that the pills can’t hurt and might help. Certainly, specific formulations can be useful. Children need lower amounts of nutrients, for example, and women, after menopause, need less iron than younger women.

But other little bottles hint at more: breast health, memory enhancement, energy boosts or increased manliness. Such claims are so thin on science that every word on the packaging is carefully calculated to be a non-promise. “If it sounds too good to be true, it is,” Blumberg warns.

It’s tricky stuff, deciding how much of which nutrient to take in supplemental form for optimal health -- especially if one rejects the one-size-fits-all multivitamin for a personalized regimen. “If you were sufficiently expert in nutrition and could conduct a full dietary and nutritional status assessment, then you could certainly design an individualized supplement regimen,” Blumberg says. “But few people are suitably qualified.”

Problems come with popping megadoses of individual vitamins. The recommendation for vitamin B6, for example, is 1.3 milligrams for adults, slightly higher for people older than 50. It’s often sold in tablets containing many times that amount.

“We get concerned when people overdo it,” Rosenbloom says. A few years ago, she says, there was a trend among women to take huge doses of vitamin B6 in the hope of reducing symptoms of premenstrual syndrome. “People were taking hundreds, even thousands, of times the recommended dose....they were having numbness in their legs, tingling in their fingers.” Some years later, an Institute of Medicine committee looking at the safe, upper limits of vitamins found that above 100 milligrams, B6 can indeed cause such numbness.

That is not the only case the panel reported of mega-doses causing harm. Too much niacin, more than 35 milligrams a day, can cause flushing and itching. People with a deficiency in vitamin B12 -- and that includes a lot of elderly people -- are at risk of crippling neurological damage if they take too much folic acid, because the substance masks their B12 deficiency, leaving it to languish untreated. The committee set an upper limit of 1,000 micrograms of folic acid a day. (The recommended dose is 400 micrograms, more for pregnant and lactating women.)

People can also get in trouble overdosing on vitamins A, E, D, niacin, zinc and selenium, the panel members found.

Multi-tasking

Mega-dosing is one thing. A humble multivitamin is another. Those who favor its use point to studies such as one published in 2003 that found people ages 45 to 65 who took a daily multivitamin and mineral supplement had fewer colds and other infections than those given a placebo.

The improvement was largely seen among the people in the study who had diabetes. Over the course of a year, only 17% of people with diabetes who took vitamin pills reported an infectious disease, compared with 93% of those who took a placebo.

That study clearly suggests that those with an underlying disease, diabetes, interfering with their nutritional intake, stand to experience a significant improvement. For them, a vitamin pill is a good backup.

But the study offers no evidence that people already getting ample nutrients in their diet will fare better with a pill.

There were some clear messages from this year’s NIH study, McGinnis says. Examining all evidence available through clinical trials, the panel found three well-established benefits from specific vitamins: Folic acid protects against neural tube disorders in developing fetuses; calcium combined with vitamin D helps prevent bone fractures; and vitamins C, E and zinc in combination reduced eyesight deterioration from age-related macular degeneration.

“There are some suggested benefits from more limited studies,” McGinnis says. “For example, selenium, vitamin E and beta carotene may reduce some cancers.” But the panel also found evidence that calcium and vitamin D could increase the risk for kidney stones. “And the use of beta carotene among smokers actually increased the risk of lung cancer,” McGinnis says.

Even those most dismissive of daily vitamins are quick to concede that specific groups of people, including those with underlying problems such as diabetes, have nutritional needs not typically met through diet. Almost everybody older than 65 needs aB12 supplement, for example. People dieting to lose weight and eating fewer than 1,500 calories should also take a multivitamin, as should pregnant women and women of childbearing age.

“It all depends on where you are in life,” says Ann Yelmokas McDermott, project director of the Boston Obesity, Genetics and Lifestyle Study at Tufts.

But in some ways, hand-wringing over the role of multivitamins boils down to concern over the American diet. There are no food shortages in this country, and people routinely eat far more calories than they need -- but still, Blumberg says, most Americans don’t get even half of their recommended dose of vitamin C, and fall way short of vitamins A and E, and such minerals as magnesium and potassium.

Those wishing to see how their nutrient intake, from food alone, measures up to their daily needs can visit the Department of Agriculture website: www.mypyramid.gov. People can plug in vitals such as age, sex, weight and exercise, log in all the food they eat in a day and see where they fall short on vitamins and minerals. When Rosenbloom asks students to do this, they’re often surprised. “They’re taking vitamin C (supplements) but find they’re getting plenty of vitamin C in their diet,” she says. “Or they’re not taking calcium supplements, and find they’re not getting enough.” The website, she says, might help people see where they’re falling short.

And, should they opt for supplements, at least they’ll do so in a way that is safer and more scientific than a scattershot selection of individual vitamins.

Yet many nutrition experts believe that the real issue is different -- that Americans need to simply eat better. “We need to focus on the quality of our diets,” says McGinnis. “We don’t know how all of these micronutrients work.

“We can take a guess that one element in a food is the responsible agent, good or bad -- but it’s a guess.”

susan.brink@latimes.com

Susan Brink is a Times staff writer. Sara Solovitch is a freelance writer.

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(BEGIN TEXT OF INFOBOX)

Supplemental information

Emily Sohn

Want to take vitamins? Here are guidelines from health experts.

How do I choose a multivitamin?

Generic and brand name vitamins usually contain similar ingredients. Some may have forms of vitamins that are easier to absorb than others, but considering that you may be taking these pills every day for the rest of your life, cost should be your first priority. Look for a budget-friendly product that contains no more than 100% of recommended daily values of essential vitamins and minerals. Too much of these substances -- especially iron, vitamin A and zinc -- can be toxic.

When should I consider supplementing my multivitamin with more vitamins or minerals?

If you are a heavy exerciser, you might need extra vitamins and minerals, especially iron, vitamin C and E. Women of childbearing age need to get enough folic acid. Menstruating women need more iron than others. Older women often need extra calcium because of lowered acidity in their stomachs, and B12 can help the hearts of elderly people. Evidence is growing that everyone needs more vitamin D.

How should I store my vitamins?

Keep them in a cool, dark place such as a kitchen pantry. Unless the label indicates otherwise, there is no need to keep them in the fridge. (Some supplements, such as fish oils, can become rancid unless refrigerated.) Storage in steamy bathrooms isn’t ideal. And, of course, keep vitamins away from kids.

How long will my vitamins last?

If you want to be sure they’re potent, don’t keep them past the expiration date. No expiration date? Don’t buy it.

Why are vitamin pills often so large?

There’s a lot of stuff in there! The more nutrients inside, the bigger the pill. Protective layers and time-release coatings can also bulk a vitamin up.

Can I chew them if I have trouble swallowing them?

If swallowing pills is a problem for you, look for smaller pills, chewable products or vitamins in powder or liquid form. It’s not a good idea to chew pills that are meant to be swallowed. Besides tasting horrible, many vitamin pills are designed with special coatings that boost the body’s ability to absorb the nutrients.

Many multivitamins now add herbs and phytonutrients, such as lycopene. Is there any added benefit to these?

Maybe, but for now, it’s probably not worth the extra money. Studies show that people who eat a lot of tomatoes, for example, have a lower risk of prostate cancer, and tomatoes are high in lycopene. But we don’t know how our bodies react to synthetic versions of the nutrient, and vitamins may not contain enough to make a difference. Studies are looking into ginkgo’s effect on memory, ginseng’s ability to treat fatigue in cancer patients, and more. Some extras you might want to take: omega-3 fatty acids, to support heart health; lutein, to fight macular degeneration; and coenzyme Q10, to help lower cholesterol.

When should I take my vitamin?

Whenever it’s easiest for you to remember. Certain vitamins -- A, D, E and K -- are fat-soluble, so taking your multi with food is a good idea.

Should everyone take a multivitamin?

Ideally, you should be able to get everything you need by eating a good diet, full of fruits and vegetables. If that’s not possible (or if you live on junk), multivitamins work like an insurance policy. Vegetarians often miss out on some of the Bs. And everyone age 65 and older could probably benefit from a daily multivitamin, mostly because declining appetites and desensitized taste buds make it difficult to get enough of everything. It’s a good idea to talk with your doctor before popping any pill. Some supplements can interact with each other in dangerous ways.

Where can I learn more about vitamins and minerals?

Here are some reliable sources:

www.nlm.nih.gov/medlineplus/vitamins.html;

www.hsph.harvard.edu/nutritionsource/vitamins.html;

www.feinberg.northwestern.edu/nutrition/fact-sheets.html.

-- Emily Sohn