KNOW WHAT YOU NEED BEFORE POPPING PILLS
In the early 1900s, Americans consumed all of their nutrients by eating food. In 2007, vitamin supplement sales topped $23.7 billion in the United States, according to the American Dietetic Association. But consuming more vitamins does not necessarily add up to improved health. How do you know what vitamins you need to take, if any, and what amount is appropriate?
Find Out What You're Missing
After moving from Florida to New York and starting a night job, Heidi Smith felt like she was always running on empty. "For years I thought I was just a grumpy, low-energy person," Smith explained. "I wish I'd known sooner that I just lacked vitamin D."
Working at night limited her exposure to the UV rays that help the body synthesize vitamin D. "Plus," she admitted, "I was eating pretty badly." When therapy and antidepressants failed to do the trick, she visited her physician, who tested her vitamin D levels and discovered a severe deficiency -- one that dietary changes alone would not rectify. Since being treated for a vitamin D deficiency, Smith has seen huge improvements in her energy level, "as though a cloud has been lifted," she said.
Most health-care practitioners agree that whole, natural foods remain the optimum source of nutrients. If your diet is lousy or your body's ability to absorb vitamins is compromised, however, you may require supplements. Registered dietitian Lauren Schmitt recommends that populations at risk for not meeting their nutrient needs, such as elderly adults, pregnant women and children, consider a basic multi-vitamin supplement. Women who experience heavy menstrual bleeding, strict vegans and vegetarians, and anyone who consumes fewer than 1,600 calories daily or can't stick to a balanced diet may also require supplements.
Various medical conditions, such as chronic digestive diseases and food intolerances, also create a need for vitamin supplements. Though numerous natural health-care practitioners use blood tests that supposedly check your nutrient levels, the tests lack scientific validity. If your doctor suspects a vitamin deficiency, he will likely run standard health tests, such as checking your blood cell counts, glucose levels, electrolytes and organ function. He will also ask you questions about your diet and lifestyle. In other words, vitamin deficiencies are diagnosed based on the symptoms they present and confirmed by your doctor's assessment of your overall health and dietary habits.
Though people's specific dietary needs vary, certain nutrients are commonly lacking in the typical American diet.
Even if you consume a relatively healthy diet, you may be missing particular nutrients. The vitamin supplement most people should consider taking is vitamin D, according to Luigi Gratton, clinical nutrition specialist at the UCLA Risk Factor Obesity Program---the nutrient that had such a powerful impact on Smith's life. "Most folks in North America are deficient," Gratton explains. The U.S. Institute of Medicine of the National Academy of Sciences recommends 5 micrograms of Vitamin D daily for those under 50.
Vitamin D is essential for proper calcium absorption and healthy bones. It also enhances your immune system and, for severely deficient people like Smith, your moods. If you rarely spend time outside and do not consume vitamin D-fortified dairy products, fish and other seafood regularly, discuss your need for vitamin D supplementation with your doctor.
Deficiencies of other vitamins are uncommon in people who live in the United States. If you consume a strict vegetarian or vegan diet, or suffer from the autoimmune disorder known as pernicious anemia, you may lack vitamin B12. The nutrient is found mainly in animal-derived foods and plays a major role in brain function, blood cell production and fatigue prevention. If you have a disorder that causes nutrient malabsorption, such as celiac disease or Crohn's disease, you may have difficulty absorbing all nutrients, particularly if you fail to manage your disorder appropriately.
The American Dietetic Association recommends consuming more of the B vitamin folate -- or the synthetic form, folic acid -- if you are pregnant, nursing or may become pregnant. Prenatal vitamins generally contain sufficient amounts of folate, as do whole grains.
Consuming plentiful amounts of nutrients from food sources rarely causes problems. Excessive intake of most any vitamin supplement, however, can lead to a broad range of side effects, some of which are serious.
Vitamin supplements have been linked to nausea, diarrhea, stomach cramping, reduced cognitive abilities, interactions with medications and even death. For example, taking excessive doses of vitamin A in supplement form causes hypervitaminosis A -- a condition characterized by liver abnormalities, reduced bone density and birth defects. Excessive intake of vitamin B12, though not associated with toxic effects, can interact with medications, such as certain antibiotics and diabetes medications. Schmitt also describes taking unnecessary supplements as "not good use of your hard-earned money."
To prevent unwanted side effects, avoid vitamin supplements that contain mega amounts -- more than 100 percent of the recommended daily allowance -- of particular nutrients and those that promise miraculous benefits. By law, the standard RDA is always listed on product packaging. Find that fine print and read it before taking any new supplement.
Take fat-soluble vitamins with healthy fat. Because fat-soluble vitamins, such as vitamins E and K, are best absorbed when consumed with some fat, take your multivitamin supplement with a meal that contains a healthy fat source, such as olive oil, nuts or fish oil. Taking vitamins with food can also help prevent mild nausea, which is possible particularly with B vitamins.
Divide your doses. Selecting vitamins that can be divided into two smaller doses can enhance your absorption, according to Dr. Mahmet Oz, television medical expert and author of "You: The Owner's Manual." To reap maximum benefits, select "mini" vitamins that require two to three capsules per day or large vitamins that can be cut into two.
Maintain freshness. If your vitamins have expired, toss them out. Keeping your vitamins in the refrigerator may help preserve their freshness and effectiveness.
How Much is too Much of a Daily Vitamin Dose?
Vitamins are necessary to your diet because they provide your body with nutrients for basic biological functions. They work together with your existing enzymes to support metabolism and tissue repair. The majority of your vitamin intake is supplied by the various foods you eat. Taking more than the daily recommended dosage for most vitamins does not generally cause adverse effects. Supplemental forms of vitamins that exceed the tolerable upper limits can increase the risk of toxicity, however.
Tolerable Upper Intake Levels
The Food and Nutrition Board serves as the regulating body of vitamin intakes and upper limits. The board sets clear guidelines for you to follow to prevent you from exceeding the average dose of vitamins per day. The maximum dose you can take to prevent adverse effects is referred to as the tolerable upper intake level, or UL. In most instances, consumption of vitamins from foods that may exceed the recommended dietary allowance, or RDA, does not cause toxic effects but this is not the case with supplemental use of vitamins. The Institute of Medicine and U.S. Department of Agriculture websites publish the ULs online and in chart form to help you safely consume adequate amounts of vitamins. Vitamin supplements are not necessary if you are generally healthy and consume a well-balanced diet. Some conditions, however, warrant taking supplements to prevent specific vitamin deficiencies, such as in the case of niacin deficiency due to poor digestive absorption.
UL for Vitamin A
Vitamin A is fat-soluble, meaning it accumulates and stores in your body for later use. Vitamin A is a general term referring to several related compounds like retinol or retinal, which are preformed versions of vitamin A. In your body, these compounds convert to other chemical structures used to facilitate various functions. Beta-carotene and the carotenoid compounds are grouped as provitamin A carotenoids and these come from dietary sources like squash or spinach. The preformed compounds in supplements are more likely to cause toxicity if you exceed the ULs. The UL for preformed vitamin A in adults is 3,000 micrograms per day. Liver toxicity, severe headaches, skin roughness, hair loss and bone pain are associated with excess doses of preformed vitamin A.
UL for Vitamin D
Vitamin D is the other fat-soluble vitamin that can become highly toxic if you take excess supplemental doses. Vitamin D is synthesized in your skin as cholecalciferol, or D-3, upon exposure to ultraviolet-B radiation from sunlight. Some foods like milk are fortified with vitamin D but the range of foods is limited, which makes deficiency of this vitamin increase in those who do not get regular sun exposure. The risk of skin cancer is also an issue for obtaining natural sources of vitamin D. The UL for vitamin D in adults is 100 micrograms. Vitamin D toxicity is not common from sun exposure but excess intake of supplemental form induces high serum calcium levels that can result in bone loss, kidney stones or organ calcification. Pain in the joints, nausea and alternating constipation with diarrhea are symptoms of vitamin D toxicity.
UL for Vitamin C
Vitamin C is water-soluble, so you need to consume the recommended allowance daily because it is quickly used and eliminated from your body. This vitamin is associated with high dose usage for improving the immune system and warding off the common cold. Exceeding the UL for vitamin C can become toxic, however, especially if you have ever experienced kidney or gallbladder stones. Your body metabolizes a small portion of vitamin C to produce oxalate, which is a substance that induces stone formation in already compromised kidneys. Excess use of vitamin C increases your risk of stone formation and it can also cause temporary headaches or diarrhea. The UL for vitamin C in adults is 2,000 mg per day.
Additional Vitamin ULs
The the majority of the B vitamins have no upper limit restrictions. Vitamin B-6 in very high doses can cause nerve damage, however. Niacin, or vitamin B-3, is associated with adverse effects from high doses like flushing, blood pressure changes and gastrointestinal disturbance. The UL for vitamin B-6 in adults is 100 mg per day and for niacin it is 35 mg. Folate is the other B vitamin with an UL of 1,000 micrograms per day but adverse effects are associated with supplemental forms rather than dietary folate. Vitamin E, an important antioxidant that also protects your cells and skin, has a UL of 1,000 mg per day. Toxicity of supplemental vitamin E is associated with excessive bleeding.