Forty percent of all Americans take their morning vitamins as regularly as they brush their teeth, convinced that these supplements will put a sparkle in their eye, a bounce in their walk and make up for the fact that their dietary intake over the last 12 hours has included a giant Whopper dripping with grease and a 13 ounce bag of potato chips. But will they?
Then there are people who are, perhaps, overzealous about their nutritional status. They take multivitamins too, and they also consume nutrition bars, health drinks, herbs, supplements and mega-doses of single vitamins in such quantities that medical researchers worry they may harm themselves.
While multivitamins do supply essential nutrients, medical experts agree that the best source of those nutrients is healthy food. If you are a nonsmoker who eats a balanced diet and exercises regularly, chances are you don’t need to take multivitamins on a regular basis. Doctors continue to recommend multivitamins for people whose lifestyle choices, overall health status or medication regimen make it difficult for them to absorb the nutrients in their food properly.
Aging, for example, reduces the body’s ability to absorb vitamins like B-12 and D; for that reason, physicians recommend that people over 60 take multivitamins. But even the practice of prescribing prenatal vitamins for all expectant mothers has fallen under scrutiny recently: there is some evidence that these supplements continued into the third trimester can lead to a rise in premature births while Vitamin A has been linked to birth defects.
Checking with Your Physician
If you and your physician decide that a multivitamin is right for you, keep in mind that the inexpensive kind on your pharmacy or supermarket shelf is just as good as the boutique brand you find in the health food store.
Read the labels carefully: information should include the dose of each vitamin and what percentage that dose is of the recommended daily dosage. Avoid megadoses: your daily intake should match the government’s Dietary Reference Intakes (DRI) and never exceed the upper limit (UL). Dosages will be listed as milligrams (mg), micrograms (mcg), or in the cases of Vitamins A, D, and E, international units (IU.) The acronym USP on the label means standards established by U.S. Pharmacopeia. Don’t buy anything past its expiration date: vitamins lose potency over time, especially in hot and humid climate.
Multivitamins are classified by the United Nations’ authority on food standards as food and sold without a prescription, but that doesn’t mean you shouldn’t treat them with the same caution and respect you use with other pills you take.
History of Vitamin Use
Long before the birth of Christ, Egyptian physicians came up with a novel cure for night blindness: slabs of cooked beef liver placed over the afflicted persontms eyes. As bizarre as this treatment may sound, it wasn’t too far off the mark. Beef liver is an excellent source of Vitamin A or retinol, known to play a critical role in vision; night blindness is one of the earliest signs of a Vitamin A deficiency.
It wasn’t until the eighteenth century, however, that a scientist first proved that it was a substance a particular food that produced curative effects, and that that substance could be given independently of the food. In one of the first clinical experiments in the history of medicine, Scottish physician James Lind showed that the ascorbic acid in citrus fruits prevented scurvy, a disease affecting collagen synthesis.
In 1911, the Polish biochemist Casimir Funk postulated the existence of essential nutrients which he called vital amines, later shortened to vitamins. He became the first scientist to isolate a vitamin, nicotinic acid (also called niacin or vitamin B3). Dr. Albert Szent-Gyorgy earned the Nobel Prize in Medicine in 1937 for the discovery of Vitamin C.
The first multivitamin, made from vegetable and fruit extracts, was marketed by the Nutrilite Company in 1934. Today the nutritional supplement and multivitamin industry are among the fastest growing, are the most popular nutritional supplements, with annual revenues of around $20 billion.
What’s In a Multivitamin?
The term multivitamin is something of a misnomer, since the supplements generally contain minerals as well. A vitamin is a chemical compound the body cannot synthesize for itself but which is necessary in small amounts in order for the body to functions optimally.
Over the counter multivitamins come as tablets, capsules, chewable tablets, soft gels and liquids. (Intravenous multivitamins are only available by prescription.)
Multivitamins should be stored in a cool, dry place and kept far away from children.
Basic multivitamins usually contain the following nutrients:
- Vitamin C (ascorbic acid): A water-soluble vitamin that plays an important role in the absorption of iron and essential for the formation of collagen in bones, cartilage, muscle, and blood vessels.
- A Vitamin C deficiency causes scurvy.
- Vitamin B1 (thiamine): Essential to a wide variety of body functions including electrolyte channels in and out of nerve cells, multiple enzyme processes and carbohydrate metabolism. A Vitamin B-1 deficiency causes beriberi.
- Vitamin B-2 (riboflavin): Essential for normal cell function, growth, and energy production.
- Vitamin B-3 (niacin, nicotinic acid, niacinamide.) A Vitamin B-3 deficiency causes pellagra.
- Vitamin B-6 (pyridoxine): Essential for the synthesis of the neurotransmitters serotonin and norepinephrine as well as for the formation of myelin, the insulation coating nerve sheaths.
- Vitamin B-9 (folic acid): A folic acid deficiency causes anemia.
- Vitamin B-12: Necessary for DNA synthesis; also important in helping to maintain healthy nerve cells and red blood cells.
- Vitamin B-5 (pantothenate): Necessary for the breakdown of carbohydrates, proteins, and fats.
- Biotin: Important to the metabolism of amino acids and carbohydrates; essential in the formation of fatty acid and glucose by the body. A biotin deficiency causes skin rash, loss of hair, high blood levels of cholesterol, and heart problems.
- Vitamin A (retinol): Vitamin A is essential to a great variety of physiological processes within the body, most notably vision and cellular growth. In amounts greatly exceeding the recommended daily allowance, Vitamin A can be toxic.
- Vitamin E: An antioxidant.
- Vitamin D: Maintains healthy blood levels of calcium and phosphorus. A Vitamin D deficiency causes rickets and osteomalacia.
- Vitamin K : a factor in normal blood clotting. A Vitamin K deficiency causes bleeding that’s difficult to control.
Multivitamins also generally contain the following minerals in trace amounts: potassium iodide, cupric, selenomethionine, borate, zinc, calcium, magnesium, chromium, manganese, molybdenum, betacarotene, and iron.
The proportions of these ingredients vary with the formulation. Multivitamin manufacturers tend to segment their market by consumer life stage and, to a lesser degree, lifestyle choice. There are children’s multivitamins, multivitamins for active adults, multivitamins for less active adults, multivitamins for age 50+, multivitamins for vegetarians “ and so on. A multivitamin designed for a woman over 50 will not have the same composition as a multivitamin designed for a woman of 30: it will contain less iron, for example “ because a post-menopausal woman’s iron requirements are less than those of a woman who’s menstruating regularly “ and it may contain higher levels of zinc and Vitamin B-12. Multivitamins formulated for different consumer sectors reflect these kinds of differences.
The amount of vitamins an individual requires on a daily basis will be determined by her metabolic needs. A guesstimate comes from weighing biometric factors like height, weight, age, gender and physical activity. Averages for each consumer segment a particular multivitamin variety is marketed to determine the exact composition of ingredients in the supplement. Optimally a multivitamin should contain 100% of the Recommended Daily Amount (RDA) of each ingredient for the person who is taking it.
Do Multivitamins Work?
The scientific community has widely divergent views as to whether the regular use of multivitamins have a demonstrable effect on health status.
A 2002 report released by the Council for Responsible Nutrition (CRN) reviewed ten years worth of scientific investigation into the health benefits of multivitamins and other selected nutritional supplements, concluding that they have an important role to play in maintaining good health since even a healthy dietary intake may fall well short of the RDA for many nutrients.
But a longitudinal health study released in 2009 concluded just the opposite. As part of the government-funded Women’s Health Initiative research effort, physicians from around the nation tracked the health status of 161,808 women. Forty-two percent of these women took multivitamins regularly. At the end of eight years, researchers compared the rates of breast cancer, colon cancer, heart attack, stroke, blood clots and mortality between the two groups and concluded there were no significant differences. The findings of this study were published in the February, 2009 issue of the Archives of Internal Medicine.
The Truth About Vitamins
One of the great benefits of multivitamins are their convenience. The truth is that even those of us who know better don’t always eat healthily. We start out each day with the best of dietary intentions, but around two o’clock in the afternoon when our energy is low, to a lot of us that box of cookies looks better than that apple. A multivitamin supplement at least ensures that however far you stray from a balanced diet, you will still get all the essential trace nutrients you need.
Some people are just picky eaters. This is particularly true of children. Sure, if you were the perfect parent you would fight all those wars at the dinner table. Eat your broccoli! you’d scream at that recalcitrant child. It’s an excellent source of the vitamins K, C, and A! But ˜fess up: sometimes isn’t it just easier to let it go, safe in the knowledge that they’ll be getting those vitamins from those Flintstones gummies you slipped them this morning?
Multivitamins are also useful for people whose specialized nutritional needs make it difficult for them to get all their essential nutrients from their diet. These people include:
The elderly. Clinical vitamin and mineral deficiencies have been found in nearly one-third of all adults over 75. This may simply be due to the fact that many of them are no longer eating balanced diets: appetites decrease as we grow older; we tend both to eat less food and fewer varieties of food. The average 75 year old consumes 1,200 calories a day (compared to the 2,000 calories necessary to meet the RDAs for necessary vitamins and minerals.)
Nutrient deficiencies of particular concern to the elderly are iron, calcium, magnesium and zinc; b-vitamins like B-12 and folate, and vitamin D. Anemia is common among adults aged 85 and older, and as much as one-third of it has no underlying pathogenic basis but merely reflects inadequate dietary intake of iron. Calcium both lowers blood pressure and reduces the risk of osteoporosis, a disease of the bones that lowers bone density thereby increasing the likelihood of fracture. The absorption of B-12 from the intestinal tract is compromised in older adults because the level of acid in the stomach falls; B-12 deficiencies are associated with anemia and other blood-cell disorders, neurological disorders, and elevated risk factors for coronary heart disease.
Additionally, many of the medications prescribed most often for elderly adults like corticosteroids, anticonvulsants, thyroid hormone, antibiotics, laxatives and diuretics, interfere with the absorption of nutrients. Daily multivitamins provide a measure of protection against these effects.
Pregnant and Breastfeeding Women
Prenatal vitamins are formulated to contain the higher amounts of folic acid, iron and calcium necessary for a healthy pregnancy and optimal development of the fetus. Folic acid prevents neural tube abnormalities while iron decreases the risk of anemia. Additional calcium helps keep the mother-to-be’s teeth and bones healthy while the baby’s teeth and bones are developing. Some research seems to suggest that multivitamins during pregnancy may also decrease the risk of low birth weight.
Vegetarians and vegans. Iron may be a problem for those who don’t eat meat, but if you make your food choices carefully, you may not need to supplement your diet with a multivitamin.
Smokers. Research indicates that smoking depletes Vitamin C. Smokers therefore may need to supplement their Vitamin C intake. Vitamin C may improve circulation and provide some measure of protection against obstructive lung disease in smokers.
Heavy Alcohol Consumers. Chronic alcohol abuse leads to a myriad of nutritional and vitamin deficiencies, particularly in the B complex. Thiamine and folic acid are often prescribed as part of alcohol withdrawal treatment.
A good deal of research in recent years has been devoted to exploring the dark side of popping vitamins. Problems arise from the belief that if 100% of the recommended daily amount of a vitamin is good, then 200% of the recommended daily amount of that vitamin is even better. This is not a problem with water-soluble vitamins like the B complex and ascorbic acid: whatever your body does not need will merely be excreted in your urine.
But it can present a hazard with fat-soluble vitamins like Vitamin A and Vitamin D which your body stores for some period of time, presenting the possibility that toxic levels may be reached. In fact many multivitamin manufacturers intentionally overestimate the dosage of their vitamin components, by as much as 50%, citing the need to extend the product’s shelf life.
The symptoms of Vitamin A overdose include hydrocephalus, severe headaches, vomiting, fatigue and constipation while symptoms of Vitamin D overdose include nausea, vomiting and loss of appetite. Prolonged Vitamin D toxicity results in the deposit of calcium crystals in the body’s soft tissues that can cause irreversible harm to your kidneys, heart and lungs.
Most synthetic vitamins are now manufactured in China, the same people who gave us poisoned pet food and toxic toothpaste. While no accusations of similar wrong doing have ever been made against the Chinese vitamin manufacturing industry, it is worth keeping in mind that industry manufacturing standards are very different in China than they are in the United States. The United States does not require country-of-origin labels on multivitamins but if this is a concern, you may want to stick with organic multivitamins made in the USA.
Shopping for Multivitamins
Multivitamins are widely available without prescription in supermarkets, pharmacies, health food stores and specialty dietary supplement stores as well as online.
In a recent round of multivitamin product testing, ConsumerLab.com found that nearly half of the supplements it tested had either much more or much less of the essential nutrients listed on the label or was contaminated with toxic substances such as lead. The cost of the product bore no relation to how pure ConsumerLab.com found it: two of the most expensive multivitamins, The Greatest Vitamin in the World and Eniva Vibe priced at almost $40 per bottle, failed to meet their standards. ConsumerLab.com’s advice? Stick with familiar names like One-A-Day and Centrum which cost under $10 for a bottle of 100 pills.