Confused about the many probiotics supplements out there? Here’s how to get the best bugs for your buck.

• Read the label
Probiotic supplements should list each bacteria species they contain, and they should guarantee the number of viable cells—CFU (colony forming units)—per gram at either the time of manufacture or purchase. Experts generally recommend a daily intake of 2 to 5 billion CFU per day. Look for products with 1 billion or more live bacteria guaranteed at time of purchase. If the label is unclear, contact the manufacturer directly—most list their web address or toll-free numbers on the box or bottle.

• Feed your bacteria
Prebiotics such as inulin and fructo-oligosaccharides (FOS) are indigestible substances in food that pass through your digestive tract and help feed beneficial bacteria. They can be purchased separately or combined with probiotic supplements. Food-friendly sources of naturally occurring prebiotics include garlic, asparagus, Jerusalem artichokes, and chicory-root tea.

• Chill out
Healthcare practitioners often recommend refrigerated brands that you should also keep chilled at home. Some manufacturers, however, freeze-dry their probiotics to make them shelf-stable. ConsumerLab.com, an independent laboratory, tested scores of probiotic products for activity and purity. Go to its website, www.consumerlab.com (you’ll need to buy a subscription—$27 for one year) to view the ones that passed.

• Get Fresh
Exposure to moisture, oxygen, or heat can negatively affect probiotics. Pay attention to the expiration date on the bottle, and buy the freshest product you can find. Then keep it refrigerated to prolong its shelf life and maintain its viability—even if you’re using the freeze-dried variety.

• Time it Right
Here’s where the rules start to blur. Most health practitioners recommend that you take probiotics on an empty stomach, between meals. They don’t always agree, however, about when to begin probiotic therapy if you are taking antibiotics. Some say to wait until you complete the course of antibiotics since they will wipe out whatever good bugs you take in. Others, such as natural health guru Andrew Weil, MD, suggest you begin probiotics immediately, claiming that enough of the bacteria will survive to protect your gut. Brigitte Mars, author of Sex, Love & Health: A Self-Help Health Guide to Love & Sex (Basic Health Publications, 2002) strongly recommends that women prone to vaginal yeast infections take probiotics “a few hours before or after the antibiotics for at least two weeks, but preferably for a few months afterward.”

• Go Gourmet
These bacteria are your gut’s tried-and-true allies. Purchase them alone or in combination, and enjoy better health.
Lactobacillus acidophilus promotes good digestion, combats antibiotic-associated diarrhea, and boosts immunity.
L. bulgaricus reduces the severity of childhood intestinal diseases, including diarrhea.
L. plantarum helps irritable bowel syndrome and prevents post-surgical infections.
Bifidobacterium bifidum is an excellent immune-booster, especially for children.
Saccharomyces boulardii helps reduce the incidence of antibiotic-associated diarrhea. Preliminary studies indicate it may be effective in treating ulcerative colitis.