What are alginates?Alginates are edible compounds derived from brown algae. When exposed to liquids, alginates become gels and expand. In supplements, foods, and drugs, the most common forms of alginates are aliginic acid and sodium alginate (see What It Is).
Are alginates effective in treating gastroesophageal reflux disease (GERD)?Alginates have been clinically shown to be more effective than antacids in treating symptoms of GERD (gastrointestinal esophageal reflux disease) such as heartburn (acid in the esophagus), regurgitation, and indigestion. Alginates appear to work by forming a floating physical gel barrier that protects the upper part of the stomach and lower esophagus (see What It Does).
Be aware that some supplements may worsen symptoms of reflux.
What did ConsumerLab's tests of alginate products show?ConsumerLab tested alginate supplements (including chews, capsules, and a liquid gel) to determine if they actually contained their claimed alginates and were not contaminated with excessive amounts of heavy metals (lead, cadmium, and arsenic).
Although all products were found to contain the types of alginates they listed, one slightly exceeded a strict limit on lead contamination - possibly due to other ingredients in the product (see What CL Found).
Interestingly, ConsumerLab found that the cost to get a significant dose of alginate (500 mg of alginic acid) ranged from 35 cents to nearly 5 times as much -- $1.61.
Which are the best alginate supplements?Among products that were Approved for quality in CL's tests, CL selected two Top Picks -- one that provides only alginate and another that is an alginate/antacid combination. These products were high in quality, relatively low in cost, provided a substantial dose of alginate along with a sensible daily use recommendations, and were among the most pleasant to take in terms of taste and/or odor.
Are there safety concerns with using alginates?Although relatively safe, sodium alginate should be avoided if you need to limit sodium (salt) intake. Products in capsule form could be potentially dangerous to those who have trouble swallowing capsules. Large intake of alginates may interfere with absorption of some minerals and vitamins (see Concerns and Cautions for details).