Why Will Metamucil Affect Vitamins?

Metamucil is a fiber supplement derived from psyllium seed husks. The soluble and insoluble fiber from psyllium husks expands when exposed to water to form a thick gel. Taking vitamins or other medications along with a fiber supplement may reduce the amount absorbed into the bloodstream, as a result of medication being detained in the fiber mass in the intestines and excreted.

Fiber supplements powder in a bowl next to juice and fruit. (Image: Heike Rau/iStock/Getty Images)

Uses of Psyllium Husk

Psyllium husk is used to bulk up stool and to treat both diarrhea and constipation. Psyllium is also used to make bowel movements more comfortable in those suffering from irritable bowel syndrome, hemorrhoids and other intestinal problems. Medical studies suggest that supplementation with psyllium husk may improve blood sugar regulation in diabetics and may reduce the risk of colon cancer.

Psyllium Husk and Vitamin Absorption

Because of the large increase in bulk in the intestines caused by psyllium husk, it may reduce the absorption of vitamins or medications. The University of Maryland Medical Center recommends using psyllium husk at least one hour before or two to four hours after taking vitamins or medication.

Increasing Vitamin Absorption

Slower intestinal transport time, better solubility of vitamins and reduced amounts of accompanying fiber and fats improve absorption of vitamins. Take your vitamins with or within 30 minutes of a small meal that contains solid food and no more than 10 g of fats and a low to moderate quantity of fiber.

Factors Decreasing Vitamin Absorption

Avoid taking vitamins with a lot of fat, excessive quantities of water or on an empty stomach. Age decreases the ability of the intestines to process and absorb nutrients. Older individuals should look for vitamins that are more easily soluble, such as those in gel capsules rather than compressed tablets. Consider increasing your daily dosage after discussion with your doctor.


Check with your doctor to determine whether psyllium husk may interfere with the absorption of any medication you may be on. Consume at least 8 oz. of water with psyllium husk and 64 oz. of water per day while supplementing with it to avoid dehydration or constipation. Do not take psyllium husk if you have difficulty swallowing or a disorder affecting the esophagus.

Load Comments

Copyright © 2019 Leaf Group Ltd. Use of this web site constitutes acceptance of the LIVESTRONG.COM Terms of Use , Privacy Policy and Copyright Policy . The material appearing on LIVESTRONG.COM is for educational use only. It should not be used as a substitute for professional medical advice, diagnosis or treatment. LIVESTRONG is a registered trademark of the LIVESTRONG Foundation. The LIVESTRONG Foundation and LIVESTRONG.COM do not endorse any of the products or services that are advertised on the web site. Moreover, we do not select every advertiser or advertisement that appears on the web site-many of the advertisements are served by third party advertising companies.