Niacin (B3) is a nutrient commonly found in fortified food products. Excessive intake can cause skin reactions such as flushing and rash. It can also lead to nausea and liver toxicity.
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Stacy Wiegman, PharmD , Pharmacy, answeredSee All 2 AnswersIt's not yet clear whether taking supplements can help you live longer or stay healthy. Experts agree that taking supplements, such as a multivitamin, can prevent deficiencies of nutrients. According to a study in the American Journal of Clinical Nutrition, those who took a daily multi were 8 percent more likely to hit the recommended targets compared with those who didn’t.
But research on whether supplements extend your life or keep you healthier has been inconclusive. A National Institutes of Health expert panel concluded that there isn't enough evidence to recommend a daily multivitamin to prevent chronic disease. It is also possible to get too much of certain vitamins and minerals, especially if you often eat fortified foods, so speak with your health-care provider before taking any supplement. -
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Dr. Bryce B. Wylde , Alternative & Complementary Medicine, answeredA recent study, "Dietary supplements and mortality rate in older women: the Iowa Women's Health Study," found little evidence that dietary supplements, including multivitamins, prevented chronic diseases among women. Unless you are deficient in a particular vitamin there is little reason to take them, according to a researcher who participated in the study. Most people get sufficient vitamin intake from their food.
I’m not a strong advocate of the "multi." I am a strong advocate for functional testing and customizing individual supplement plans. -
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Stacy Wiegman, PharmD , Pharmacy, answeredSee All 3 AnswersYou can get enough vitamins from food, provided you eat a well-rounded, varied diet and you don't have any health conditions that affect what you can eat or how well your body absorbs nutrients from food. To make sure you're consuming a diet that meets all of your nutritional needs, the U.S. Department of Agriculture (USDA) suggests:
- aiming to make half of what you eat fruits and vegetables
- choosing low-fat dairy products
- consuming a variety of protein sources, such as fish, meat, chicken, eggs, beans and nuts
- making sure at least half of the grains you consume are whole grains
- minimizing your intake of high-fat foods or those with lots of added sugar or salt
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Stacy Wiegman, PharmD , Pharmacy, answeredTaking vitamin supplements may be dangerous to your health if you overdo it, which can lead to potentially dangerous side effects, or if you take dietary supplements at the same time you take certain medications, which may trigger dangerous supplement-drug interactions.
For example, some dietary supplements might interfere with cancer treatment or increase the risk of cancer coming back. Calcium supplements can interfere with your body's absorption of certain antibiotics, thyroid medication and anticonvulsant drugs. Consuming too much vitamin A may increase your risk of the brittle-bone disease osteoporosis. Too much vitamin B6 may lead to nerve problems that could throw off coordination. Ask your doctor if he recommends dietary supplements for you and, if so, the safest way to take them. -
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Dr. Bryce B. Wylde , Alternative & Complementary Medicine, answeredThe right amount of vitamin supplement to take can vary. Your diet should provide most of the vitamins your body will need.
However, a doctor might determine that you are deficient in one or more vitamins or minerals and may want you to take a supplement. It’s important to understand the risk of taking too much of what you don’t need. But you should balance that against the risk of getting too little of a vitamin in which you are deficient. Ultimately, you need to test yourself to know your specific and very individual demands. And there are many accurate tests that can help you determine those needs. -
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Stacy Wiegman, PharmD , Pharmacy, answeredSee All 2 AnswersThe health benefits of vitamin supplements are tested differently than the health benefits of drugs. Before a drug is available on store shelves or by prescription, the manufacturer does laboratory, animal and human testing on the medication, then submits all of the test results and other information available to an independent panel of experts at the Food and Drug Administration (FDA) for review. If the FDA decides that the drug is safe and effective, it may approve it for sale and distribution in the U.S.
In contrast, regulation of dietary supplements falls under a law passed by Congress in 1994 called the Dietary Supplement Health and Education Act. Under this law, the FDA does not review the safety, effectiveness or health claims of supplements before they are brought to market. The manufacturer is responsible for making sure that the product is safe and provides the benefits it claims to have on the label. Talk to your doctor for more information about the safety and effectiveness of dietary supplements. -
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Stacy Wiegman, PharmD , Pharmacy, answeredSee All 2 AnswersYou may need to take a vitamin D supplement if you avoid the sun, but that depends on what you mean when you say "avoid." If you get even a few minutes of midday summer sunlight on your arms or legs -- and a bit more in winter -- your skin may be able to produce adequate amounts of vitamin D. If you get less than that, be sure to eat foods fortified with vitamin D, take a supplement or do both.
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Dr. Michael Roizen, MD , Internal Medicine, answeredSee All 5 AnswersWhen you shop for a multivitamin, first read the label. The multivitamin should have the usual recommended daily allowances (RDAs) of vitamins and minerals. Then you need to supplement that amount, so that you obtain the RealAge Optimums (RAOs) -- the dose you need to stay young -- for each vitamin and mineral listed below. Then you have to remember five minerals (sorry, there's no shortcut).
Vitamins:
- Vitamin A -- More than 2,500 international unit (IU) is too much
- Vitamin B6 -- 4 milligrams (mg) a day
- Vitamin B12 -- 800 microgram (mcg) a day (25 mcg, in a supplement. B12 in a supplement is absorbed much better than the B12 found in food)
- Vitamin C -- 400 mg x 3 (remember it's water-soluble, so you need several doses over the day), or 1,200 mg a day (reduce this to 100 mg a day from supplements if you're taking a statin drug, for example, Zocor, Lipitor, Pravachol, or Crestor)
- Vitamin D -- 400 IU a day if under age 60; 600 IU a day if 60 or over
- Vitamin E -- 400 to 800 IU a day (400 to 800 IU of mixed tocopherols is the form of vitamin E I favor). Reduce this to at most 100 IU a day from supplements if you're taking a statin drug.
- Vitamin F (folate) -- 800 mcg a day (folic acid or folate, or folicin, which is sometimes listed as vitamin B9)
- Thiamin -- 25 mg
- Riboflavin -- 25 mg
- Niacin -- At least 30 mg a day, preferably more (check with your doctor) if you're taking a statin drug
- Biotin -- 300 mcg
- Pantothenic acid -- 10 mg
- Calcium -- 1,200 mg a day in divided doses (1,600 mg for women)
- Magnesium -- 400 mg a day
- Selenium -- 200 mcg a day
- Zinc -- 15 mg
- Potassium -- Four fruits plus a normal diet should do it.
- Lycopene -- Ten tablespoons of tomato sauce a week (400 mcg) should do it.
- Lutein -- A leafy green vegetable a day (40 mcg) should do it.
- Acetyl-L-carnitine -- If you want it, then take 1,500 mg a day.
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Dr. Michael Roizen, MD , Internal Medicine, answeredSee All 2 AnswersTo get enough nutrients, I recommend taking a multivitamin every day, in case you have missed out on a little bit of one mineral or the other. Choose a multivitamin without added iron, and one that has less than 2,500 international units (IUs) of vitamin A and beta-carotene (combined).
In fact, you should really take your vitamins (or your multivitamin) twice a day (several vitamins are water soluble and you will urinate them out so quickly that you need them twice a day to have a minimally acceptable level in your blood at all times if you do not eat a lot of fruit and vegetables at both breakfast and dinner. Further, for some such as Calcium, you cannot absorb more than 600 milligrams (mg) at a time, so you need that twice a day and for others such as vitamin C, if you take more than 500 mg at once, that increase your risk of toxicity. So to keep a steady level, to absorb the optimal level, and to minimize the risk of toxicity from too much at once, you want a twice a day multivitamin).