by Jackie Hart, MD
Q: A friend of mine told me that some of the most popular multivitamin supplements on the market are not really good for you. Is there any validity to this?
A: As your question implies, all multivitamin supplements are not created equal. For vitamins and minerals to become useful substances in the body, they must be digested, absorbed, and metabolized.
Digestion begins with chewing or swallowing and involves breakdown of products throughout the gastrointestinal tract, which includes the mouth, esophagus, stomach, small intestines, and colon. Absorption takes place primarily in the intestines, where nutrients enter the bloodstream to be delivered to all parts of the body. These nutrients are then metabolized, which involves converting them into components helpful to the body in the form of energy.
How well these three processes work collectively is often referred to as bioavailability.If vitamins are not taken in a bioavailable form?i.e., forms that are readily digested, absorbed, and metabolized into energy?then they are not useful.
Here are some ways you can ensure that the nutrients in the multivitamin supplement you take will be fully utilized by your body:
Q: A friend of mine told me that some of the most popular multivitamin supplements on the market are not really good for you. Is there any validity to this?
A: As your question implies, all multivitamin supplements are not created equal. For vitamins and minerals to become useful substances in the body, they must be digested, absorbed, and metabolized.
Digestion begins with chewing or swallowing and involves breakdown of products throughout the gastrointestinal tract, which includes the mouth, esophagus, stomach, small intestines, and colon. Absorption takes place primarily in the intestines, where nutrients enter the bloodstream to be delivered to all parts of the body. These nutrients are then metabolized, which involves converting them into components helpful to the body in the form of energy.
How well these three processes work collectively is often referred to as bioavailability.If vitamins are not taken in a bioavailable form?i.e., forms that are readily digested, absorbed, and metabolized into energy?then they are not useful.
Here are some ways you can ensure that the nutrients in the multivitamin supplement you take will be fully utilized by your body:
- Look for a multivitamin that contains a complete B complex; taking some of the B vitamins and not others is like taking none at all because you need the entire complex for absorption. The B complex consists of: thiamine (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), pyridoxine (vitamin B6), cyanocobalamin (vitamin B12), folic acid, pantothenic acid, and biotin.
- The vitamin E in the supplement should be in the form of d-alpha tocepherol, since it is more readily absorbed than dl-alpha, which is found in many supplements.
- Look for vitamin A in the form of beta-carotene, which is water-soluble and therefore does not become toxic. In addition, studies show beta-carotene to be a more effective antioxidant.
- For best absorption of calcium, make sure your multivitamin contains magnesium and vitamin D, which are both necessary for calcium to be absorbed. The amount of magnesium should be at least one-third to one-half the calcium dose.
- The mineral selenium is more bioavailable if it is bound to methionine, rather than sodium.
- Dont be fooled by words like ?chelation,? a process thought to stabilize chemical compounds. This process has not been proven to improve bioavailability, but does drive up the price of multivitamin supplements.