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Supplement Facts

From what to take to where to store them, our complete guide to the basics of dietary supplements

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Ever feel lost in the supplement aisle? Not sure what to take? Or when? Or how? And what does all that stuff on the labels mean, anyway? Here’s everything you need to know to get the most out of your supplements.

What to take
Generally, supplements fall into three categories: targeted, for conditions such as blood sugar control or menopause; acute care, for immediate concerns such as treating a cold or easing indigestion; and daily maintenance, for overall health. While age, diet, and health issues determine exactly what you need, most people require these five basics:

1. A broad-spectrum multi. It’s difficult to get all the nutrients you need from even a good diet (in one study, less than 1 percent of participants got enough vitamins from diet alone). Look for a multi that provides 100 percent of the essential vitamins and minerals (post-menopausal women and men probably don’t need iron). Divide doses-take half in the morning and half at night-to increase absorption and maintain steady blood levels.

2. Vitamin D. Studies continue to stress the importance of this vitamin-like hormone, but there’s some controversy about the proper amount to take. Because it’s fat-soluble, vitamin D can be stored in the body, and-at very large doses-be toxic. Most experts agree that up to 5,000 IU per day is safe. Just take into account how much vitamin D is in your multi, and adjust additional vitamin D supplements accordingly.

3. A calcium/magnesium combo. A combination of the two is best, but even if your multi contains both, it’s difficult to pack the recommended daily amount into one pill because they’re bulky minerals. To make up any lack, look for a combo product that contains 500-1,000 mg of calcium and 400-600 mg of magnesium. Do not take more than 500 mg of calcium at a time, as it is not removed from the blood stream quickly and higher doses can contribute to atherosclerosis.

4. Omega-3s. The best source of these healthy fats is fish oil. It contains the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that are associated with reduced risk of inflammation, heart disease, and some cancers. Vegan supplements are often high in alpha-linolenic acid (ALA), which the body converts to EPA and DHA. Because the conversion ratio is often low, it’s best to look for a vegan supplement with EPA and DHA from microalgae. Your best bet is a product that contains at least 500 mg of EPA and 250 mg DHA.

5. Probiotics. These beneficial bacteria strengthen immunity, aid digestion, and heal the intestines. Look for a product with different strains, and be careful with those that contain FOS or inulin-these indigestible sugars are called prebiotics and are said to “feed” healthy bacteria, but they can cause cramps, bloating, and diarrhea. Probiotic doses are measured by colony forming units (CFUs) that indicate the number of live organisms. There’s no set dose, but a range of 1 billion to 10 billion CFUs is typical. Also look for products that note a strain designation, such as DDS-1 or NCFM, which identifies strains that colonize the digestive tract.

Reading the label
You’ll find lots of interesting terminology, abbreviations, and information on supplement labels. Some things to look for:

USP Verified means that product meets rigorous standards set by the U.S. Pharmacopeia, a third-party testing service, and will be marked with a USP Verified logo or seal. (Note: USP Verified doesn’t mean the same thing as “pharmaceutical grade” or “pharmaceutical quality,” unregulated terms that have no set definition or verification process.

Standardized, used mainly with herbs, means that the preparation contains a guaranteed amount of the active ingredient in the base herb. But because herbs contain many chemical constituents that work with each other, some experts say that it’s best to take the whole herb rather than a standardized preparation.

Dicalcium phosphate, gum arabic, and alginic acid. These are binders, fillers, and/or excipients-compounds that are necessary for producing pills. They may sound scary, but most binders and excipients are made from fibers, seaweed, and plant gums, and are benign. Magnesium stearate is an exception. It’s generally sourced from hydrogenated oils-usually cottonseed oil-and some studies suggest that it may suppress immunity.

Daily values (DV). The DV is derived from the Reference Daily Intake or Recommended Daily Intake (RDI), the amount of a nutrient that is thought to be sufficient to meet the requirements of most healthy people. But the DVs don’t take into account age or gender-the same DV would apply to an eight-year-old girl and a 35-year-old man-so they’re rough guidelines at best.

Manufacturer’s Information. Labels should note the manufacturer’s name, phone number, and address or website. If they don’t, that’s a big red flag.

Good Manufacturing Practices (GMP). This is a designation provided by the FDA for companies who complete a rigorous review of their manufacturing process, including third-party evaluations of ingredients and products for purity and potency.

When to take them
Most supplements should be taken with meals to increase their absorption. Fat-soluble vitamins such as A, D, E, and K should be taken with a fat-containing meal. Most B vitamins should be taken with a light meal, since taking them on an empty stomach can cause nausea. The exception is folic acid, which is better absorbed on an empty stomach.

Other supplements should only be taken on an empty stomach. These include proteolytic enzymes used for joint pain; glutamine; N-acetylcysteine; amino acids; most herbs and botanicals; and fiber, which can bind to other nutrients and lessen their absorption. Taking fiber supplements with a meal can also significantly slow gastric emptying, leading to gas, bloating, and indigestion.

There’s controversy regarding when to take probiotics. Some say that food stimulates the secretion of stomach acids, which can kill probiotics, so they should be taken on an empty stomach. Others say that food buffers strong stomach acids and allows the probiotics to reach the intestines unscathed, so they should be taken with meals. Your best bet is to divide doses of your probiotic and take half with meals, half on an empty stomach.

How to store them
It may seem counterintuitive, but the worst place to keep your supplements is in the medicine cabinet. Humidity and warm temperatures cause supplements to degrade. But don’t keep most supplements in the fridge either, since condensation can build up inside the bottles when you take them out on a daily basis. It’s okay to store extras or large quantities in the fridge, but once you’re ready to take them, remove from the refrigerator and store them in a cool, dry place. Exceptions are probiotics and fish, flax, or hemp oils, which should always be refrigerated.

Also be wary of storing supplements where they’ll be in contact with sunlight. Generally, the best location is a dark, dry, cool place, such as a pantry or cupboard. Be sure, too, that the supplements in question are stored properly at the retail outlet. A recent Consumer Reports survey found that more than half of the products tested didn’t contain the amount of probiotics listed on the label, and one contained only 7 percent of the label amount-most likely due to improper storage.

Also note that your supplement should have an expiration date that usually represents the last day of the product’s guaranteed or assumed potency. It’s likely, however, that your supplement is good for six months past that date, but if its color or texture changes-or you notice a strong odor-toss it.

What to know about interactions
Dangerous interactions between supplements are rare, but some interactions between supplements and pharmaceuticals can impact the effectiveness of either or both. For instance, St. John’s wort can increase the breakdown of estrogen and reduce the effectiveness of birth control pills. And sometimes, one supplement can reduce the effectiveness of another-for example, large doses of calcium can block the body from absorbing other minerals such as iron and zinc.

More often, it’s a case of a pharmaceutical or over-the-counter medications increasing the need for a supplement. For example, regular aspirin use increases the need for vitamin C; antibiotics damage beneficial bacteria and increase the need for probiotics; and birth control pills deplete B vitamins and zinc.

There are a few combinations that can be problematic or even dangerous. These include high-dose fish oil and warfarin, both of which thin blood and can increase the risk of bleeding; antidepressants and SAM-e or 5-HTP, which can lead to excessive levels of serotonin in the body and serious side effects; and St. John’s wort, which may interact with cardiovascular medications and antidepressants.

And there you have it. Just remember these few simple tips, and you’ll have the information you need to make the right supplement choices. And don’t forget that your natural products retailer is a great resource if you ever have questions about what you see on the shelves.

Lisa Turner is a certified food psychology coach, nutritional healer, intuitive eating consultant, and author. She has written five books on food and nutrition and developed the Inspired Eats iPhone app. Visit her online at

Internet Info
Want to know more about specific supplements? Try these websites:

  • National Institutes of Health Dietary Supplement Label Database: Full label contents from dietary supplement products.
  • The Office of Dietary Supplements: Overview of individual vitamins, minerals, and other dietary supplements
  • Medline Plus Drugs, Supplements, and Herbal Information: Info on supplements, prescriptions, and over-the-counter medicines, including dosage and side effects.

“It may seem counterintuitive, but the worst place to keep your supplements is in the medicine cabinet.”