Multivitamins are a combination of many different vitamins that are normally found in foods and other natural sources. Such preparations are often found in the form of tablets, capsules, pastilles, powders, liquids, and injectable formulations. Multivitamin and mineral supplements help ensure one is getting sufficient vitamins and minerals required for the body to function properly.
"When we compare recommendations for vitamin and mineral intakes to actual consumption, many Americans do not even come close to getting what they need for several nutrients," says Meir Stampfer, MD, DrPH, professor of medicine at Harvard Medical School.
For a vitamin formula to be considered complete, it must contain certain key vitamins. These key vitamins are basic to most multivitamin formulas. You must check the label on your multivitamin to make sure it contains the basic twelve.
Multivitamins are used to provide vitamins that are not taken in through the diet. Multivitamins are also used to treat vitamin deficiencies (lack of vitamins) caused by illness, pregnancy, poor nutrition, digestive disorders, and many other conditions.
According to the Dietary Guidelines for Americans 2005, adults are often deficient in:
Calcium
Magnesium
Vitamin A (as carotenoids)
Vitamins C
Vitamin E
"Certain groups run even higher risks for vitamin and mineral deficits," says Jeffrey Blumberg, PhD, director of the Antioxidants Research Laboratory, and professor of nutrition at Tufts University.
By supplementing the diet with vitamins and minerals, multivitamins can be a valuable tool for those with dietary imbalances or different nutritional needs. People with dietary imbalances may include those on restrictive diets and those who cannot or will not eat a nutritious diet. Pregnant women and elderly adults have different nutritional needs than other adults, and a multivitamin may be indicated by a physician.
Over time, small discrepancies in nutrient intakes can prove problematic for a person, particularly for women in their childbearing years, strict vegetarians, and the elderly.
For instance, shortfalls of iron in the childbearing years may lead to anemia. Too little folic acid very early in pregnancy increases the risk of neural tube defects in developing babies. And vitamin B12 deficits, responsible for irreversible nerve damage and faulty cognition, are more likely in people who avoid animal foods, and in people over age 50, whose bodies are often less efficient at absorbing vitamin B12.
Stampfer and Blumberg advocate multivitamins as a way to shore up diets low in nutrients. But, they warn that multivitamins are dietary supplements, not substitutes for healthy eating.
That's because multivitamins lack a number of beneficial compounds for wellness, including phytonutrients, and fiber, found in plant foods. Multivitamins also typically fall short of the recommend daily amount of calcium and other important vitamins and minerals.
"Think of multivitamins as an insurance policy, but don't fool yourself into thinking dietary supplements measure up to the benefits of maintaining a healthy body weight, eating right, and getting regular physical activity," Blumberg says.
"Overall, multivitamins are a minor component of good health, but worthy ones," Stampfer says.
The health benefits of vitamins and minerals in multivitamins include their ability to prevent and treat various diseases including heart problems, high cholesterol levels, eye disorders, and skin disorders. Most of the vitamins also facilitate the body mechanism and perform functions which are not performed by any other nutrient. Multivitamins are beneficial for the following:
vitamin A – normal vision, healthy skin
carotenoids – protection against some cancers, reduce muscle soreness
thiamine/riboflavin/niacin – converts carbohydrate to energy
vitamin C – healthy bones, teeth, gums, immune function
vitamin E – normal cell growth/development, protection against heart disease
calcium – builds bone and teeth, blood clotting, nerve/muscle function
iron – prevents anaemia, red blood cell formulation
zinc – healthy immune system, wound healing
magnesium – healthy bones, muscle/nerve function
potassium – fluid balance, muscle/nerve function
selenium – helps protect against heart disease/cancer
The main advantage of taking daily multivitamin supplements is that they are able to make up for anything that is lacking in a person's diet. Those most likely to benefit from taking such a supplement include dieters, allergy sufferers, vegans, fast-food junkies and pregnant women.
Don't bet on multivitamins to keep you free of heart disease, cancer, and other chronic illness. That's the recommendation of a 2006 State-of-the-Science Conference on Multivitamin/Mineral Supplements and Chronic Disease Prevention from the National Institutes of Health.
In the report, the 13-member panel concluded that more research is needed before suggesting multivitamin use to head off disease in healthy, non-pregnant people.
However, the NIH opinion contradicts earlier findings, including a 2002 study from the Harvard School of Medicine published in the Journal of the American Medical Association. The authors reviewed 35 years worth of research on vitamins and chronic disease, concluding that every adult should take a multivitamin daily as a safe and inexpensive way to optimize health.
Other studies highlight the connection between multivitamin use and well-being, too.
In a group of more than 88,000 women, those who took multivitamins for 15 years or more significantly reduced the risk of colon cancer as compared to those who took multivitamins for less time. The women were part of the Nurses' Health Study at the Harvard School of Public Health. The research was published in the Annals of Internal Medicine.
Another study found that taking a multivitamin reduced the risk of first-time heart attack in a group of Swedish men and women aged 45 to 70.
In bridging nutrient gaps, it is perfectly plausible to think that multivitamins help head off chronic conditions, including osteoporosis and heart disease," Blumberg says.
So why the difference of opinion?
Stampfer, who was a presenter at the NIH conference, says the panel excluded smaller trials and observational studies done with multivitamins, looking only at the results of large randomized trials, considered the gold standard of clinical studies.
However, randomized trials tend to be shorter than other types of studies, which leaves less time to see results.
There may be disagreement about multivitamins' capacity to curb chronic conditions. But on balance, the evidence for the benefits of multivitamins far outweigh the potential for harm -- considered extremely low for most healthy people -- even if the effects on health are small, says Stampfer.
If you're convinced you need a multivitamin, how do you decide which one is best for you?
Eating a balanced diet rich in whole grains, fruits, vegetables, legumes (beans), and lean protein sources most of the time means you'd do fine with a multivitamin with 100% or less of the daily value (DV) for a wide array of nutrients. Daily values, listed on food and supplement labels, help you determine how a serving of food or supplement fits into the nutrient needs of a 2,000-calorie eating plan.
When picking a multivitamin, pay particular attention to the following to maximize benefit and minimize risk.
Key vitamins; the basic twelve must be part of your multivitamin
Vitamin A—Beta Carotene, a plant chemical easily converted by the body. Beta Carotene is the best source of this vitamin, another source is Retinol. Retinol has its drawbacks, because it has been linked to reduced bone density and increased risk of hip fracture.
Vitamin C—Ascorbic acid, this is essential for avoiding such diseases as scurvy, keeps the immune system strong, and it is a very powerful antioxidant. Pure vitamin C is preferable to ascorbic acid since it's health benefits are said to be better.
Vitamin D—most multivitamins offer D2 AKA ergocalciferol, therefore it is wise to supplement with D3 AKA cholecalciferol for your vitamin D to be more complete. Most multivitamins supply 400 International Units (100% DV) for vitamin D, which is necessary for calcium absorption and may play a role in cancer prevention. Stampfer says while this is a step in the right direction, you may need more vitamin D than a multivitamin and your diet provide, especially if you have dark skin, are overweight, or spend little time outdoors in the summer months.
Vitamin E—It is wise to opt for a formula that contains d-alpha tocopherol, which is the preferred and more natural form of vitamin E, it is better than dl—alpha tocopherol which is the synthetic form of vitamin E.
Vitamin B: These consist of Thiamin (B1) Riboflavin (B2) Niacin, (B6), Folate (folic acid), B-12, Biotin, and Panthonic Acid. B vitamins are essential for energy and are quickly depleted due to stress, therefore, it is wise to supplement with a Stress B vitamin formula, if you are prone to anxiety. Women in their childbearing years need 400 micrograms of folic acid (100% of the DV) every day to help prevent neural tube defects in the first month of pregnancy. (Many breakfast cereals supply 400 micrograms of folic acid per serving.)
Minerals
No multivitamin formula could ever be considered complete without certain essential minerals.
Calcium—vital for bones, teeth and heart health. Calcium aids muscle growth and the transmission of nerve impulses, normalizes blood clotting and can even relieve anxiety and depression related to premenstrual syndrome, promotes weight loss and can help control blood pressure.
Magnesium—is consider by many the master mineral. Magnesium is responsible for many cellular functions. It aids in calcium synthesis, this contribute to healthy teeth and bones, also beneficial for muscles, nerves, and the heart. This mineral also aids in converting sugar into energy. The best ratio when couple with calcium is 2 to 1.
Potassium—aids muscle function, the nervous system, and fluid balance. The heart needs Potassium to regulate heartbeats.
Iron—helps red blood cells carry oxygen throughout the body, strengthen the immune system, assist in temperature regulation. Iron is especially necessary for menstruating women, vegans and endurance athletes, these groups run the greatest risk of iron deficiency.
Phosphorus—assists the bodily functions, including collagen, necessary for the production of bones, joints, ligaments, tendons, cartilage, skin and eyes.
Zinc—important for the healing of wounds, growth and a strong immune system.
Iodine—trace mineral involved in energy production, thyroid hormone production, and physical development.
Selenium—a trace mineral that works synergistically with Vitamin E to serve as a powerful antioxidant.
Manganese—trace mineral that aids digestion, is vital for developing strong and healthy bones, supports the nervous and reproductive system and even enhances brain function.
Chromium—a trace mineral that aids in stabilizing blood sugar and insulin levels. It also supports normal cholesterol levels.
Copper—a trace mineral that helps protect the nervous system, and promotes cardiovascular, bone, joint and skin health.
There are multivitamins for different needs
When selecting a multivitamin one must also consider the different stages in one's life as well as the different nutritional needs of each gender.
Children's Formulas—you should make sure that your little ones have the best start possible. To ensure this, get them a complete multivitamin formula made especially for children. This is necessary for healthy growth and development.
Teen Formulas—made for the young person on the go, yet still at a crucial part of his or her development. These formulations fortify the immune system, supply energy, helps to have clearer skin, relieve stress, and support proper development.
Men's Formulas—these are made with the specific need of men, multivitamins for men include such ingredients as saw palmetto, lycopene, pumpkin seeds oil, pygeum bark extract, and stinging nettle. All these herbs are vital in maintaining a healthy prostate.
Women's Formulas—target hormone balance and aid the reproductive system. Multivitamin formulations for women often contain black cohosh, phytoestrogens, blessed thistle, blue cohosh, dong quai, red raspberry, bay berry, DHEA, false unicorn, chaste tree berry, licorice root, ginger rhizome and marshmallow herb.
Anti Aging Formulas—sometime contains Oriental herbs and tonics, potent antioxidants, amino acids, and omega 3 fatty acids, these all aid in slowing down the aging process.
When choosing a multivitamin, one may want to consider whole food based vitamins, made from whole food concentrates. The premise is that when taking a whole food multivitamin, you are acquiring your vitamins from a nutrient dense food based source. The body tends to absorb these more easily than traditional multivitamins.
Many people will tell you that you should be able to get all of your nutritional needs met through the food you eat. Unfortunately, due to soil depletion and toxins that erode our bodies' nutritional reserves, we need a little extra help. Therefore, it is wise to choose a good multivitamin to ensure a stronger body and to live more disease free.
Seek emergency medical attention if you think you have used too much of this medicine. An overdose of vitamins A, D, E, or K can cause serious or life-threatening side effects. Certain minerals contained in a multivitamin may also cause serious overdose symptoms if you take too much.
Overdose symptoms may include stomach pain, vomiting, diarrhea, constipation, loss of appetite, hair loss, peeling skin, tingly feeling in or around your mouth, changes in menstrual periods, weight loss, severe headache, muscle or joint pain, severe back pain, blood in your urine, pale skin, and easy bruising or bleeding.
It is important to be aware of certain side-effects which can result from taking too high a dosage of different vitamins and minerals. In order to ensure one is sticking to a safe amount of key vitamins and minerals, check labels for the RDA, or "recommended daily amount." The RDA provides guidelines as to typical daily requirements of essential vitamins and minerals, although athletes may need more than the average person.
Many multivitamin products contain minerals such as calcium, iron, magnesium, potassium, and zinc. Minerals (especially taken in large doses) can cause side effects such as tooth staining, increased urination, stomach bleeding, uneven heart rate, confusion, and muscle weakness or limp feeling. Read the label of any multivitamin product you take to make sure you are aware of what it contains.
Other side effects associated with taking too high an amount of vitamins and mineral supplements include:
vitamin A – liver/bone damage, harm to unborn baby
carotenoids – reversible orange tinge to skin
riboflavin – yellow urine
niacin – hot flushes
vitamin C – diarrhea, excess urine formation
calcium – interferes with mineral absorption
iron – constipation, stomach pain
zinc – interferes with iron/copper absorption
magnesium – diarrhea
selenium – nausea, vomiting, hair loss
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
When taken as directed, multivitamins are not expected to cause serious side effects. Less serious side effects may include:
upset stomach;
headache; or
unusual or unpleasant taste in your mouth.
This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.