Everything You Need to Know About Vitamins

By Abigail L. Cuffey

Before you pop your next multivitamin or consider a new supplement, consider these 10 little-known facts:

1. Temperature

Refrigerate supplements that contain oils (such as fish oil or omega-3 fatty acids) or probiotics. "Heat, light and oxygen are the elements that make oils go rancid and kill probiotics," says Rashmi Gulati, MD, medical director at Patients Medical in New York. "If your pills are exposed to any of these for long, they will be completely useless."

2. Drug Interactions
If you take aspirin or are on birth control, you may need to boost your vitamin C intake. "People who frequently take moderate-to-large doses of aspirin lose vitamin C in the urine and may need higher doses to maintain their blood levels," says Kathi J. Kemper, MD, author of Mental Health, Naturally: The Family Guide to Holistic Care for a Healthy Mind and Body. Contraceptives that contain estrogen can also lower C levels.

3. Synthetic vs. Natural
Go synthetic when it comes to folate, a type of B vitamin that's especially important for women of childbearing age. Kerry Neville, RD, spokesperson for the American Dietetic Association, says that synthetic-based supplements are actually easier for the body to absorb than those made from natural sources.

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4. B12 Benefits

You might want to consider taking a B12 supplement if you don't eat much meat. Vitamin B12, an important vitamin that helps metabolize folate as well as protect the nervous system, is found mainly in animal products. "Vegans definitely need a B12 supplement because the kind found in some plant foods is in a form the body cannot use," says Elisa Zied, RD, CDN and author of Nutrition at Your Fingertips.

5. Volume
Even though vitamins are good for you, more is not necessarily better. For example, "huge doses of vitamin C or magnesium can cause diarrhea," says Dr. Kemper. Other vitamins pose even greater risk when overused, including vitamin A and niacin, which can cause liver damage and other issues.

6. Iron Awareness
If you're using a multivitamin that contains iron, be sure to take only the suggested amount per day or week. Most people don't need extra iron unless they're pregnant, anemic or have a poor diet; if you ingest too much, it's possible to overload your system, says Dr. Gulati. An excess of iron can be damaging-especially in men-to the liver, heart and pancreas.

7. Food Pairing
Fat-soluble vitamins, which include vitamins A, D, E and K (water-soluble vitamins are B-complex and C), should be taken with food that has a little bit of fat in it, says Bonnie Taub-Dix, RD, spokesperson for the American Dietetic Association. This will help your body maximize its benefits.

8. Absorption
Some medications affect the absorption of supplements, and may even deplete vitamins already stored in your body. "If you take prescription meds, ask your doctor or pharmacist if there are any vitamin interactions you should be aware of," says Neville.

9. Labeling

The FDA regulates vitamins more like food than drugs, explains Dr. Kemper. This means that they can vary in quality and the label may not accurately reflect the contents. Visit ConsumerLab.com, a website that independently tests nutritional products, to see if your vitamins are fit for consumption.

10. Your Diet
Always remember that vitamins are not an insurance policy. "Too many people think that popping a pill and not caring about what they eat is fine," says Neville. While vitamins can help keep you healthy, they aren't a complete replacement for whole foods that naturally provide an assortment of vitamins and minerals.

All photos courtesy of Shutterstock.


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