You've seen the commercials—usually a woman dancing around merrily as she eats a cup of yogurt. These ads tout the benefits of probiotics for gut health. But what exactly are probiotics, and are they truly beneficial for your health?

According to the National Institutes of Health (NIH), probiotics, live microorganisms such as bacteria and yeasts, offer numerous health benefits when consumed in adequate amounts. Naturally present in some fermented foods and available as dietary supplements, probiotics play a significant role in maintaining gut health and overall well-being.

However, not all products labeled as probiotics provide proven health benefits according to NIH.

THE ROLE OF PROBIOTICS IN THE DIGESTIVE TRACT

Probiotics primarily impact the digestive tract by influencing the gut microbiome, a complex community of microorganisms residing mainly in the large intestine. These beneficial microorganisms help protect the digestive system from harmful bacteria, improve digestion and gut function and may offer additional health benefits. Common probiotics include strains from genera such as Lactobacillus, Bifidobacterium, Saccharomyces and Streptococcus.

SOURCES OF PROBIOTICS

Fermented foods: Probiotics are naturally found in fermented foods like yogurt, which is made by adding live cultures such as Lactobacillus or Streptococcus to milk. However, the probiotic benefits depend on the types and amounts of microorganisms added. Other fermented foods, including apple cider vinegar, kimchi, kombucha, miso and sauerkraut, may contain microorganisms, but their probiotic benefits remain uncertain due to limited studies.

Processed fermented foods: Foods like sourdough bread and most pickles undergo processing that kills the microorganisms, eliminating their probiotic potential.

Unfermented foods with added probiotics: Some cereals, juices, milks, nutrition bars, smoothies and infant formulas have added microorganisms. The probiotic benefits of these foods depend on the specific strains and amounts of microorganisms they contain.

Probiotic supplements: Dietary supplements labeled as probiotics vary widely in the types and amounts of microorganisms they contain. The Supplement Facts label typically lists the total weight of microorganisms and, often, the number of colony-forming units (CFUs) per serving, which better indicates the number of live microorganisms. However, higher CFU counts do not necessarily equate to greater health benefits, which depend more on the specific strains present.

HEALTH EFFECTS OF PROBIOTICS

Research into the health effects of probiotics has revealed potential benefits in several areas:

• Atopic dermatitis: Some studies suggest that probiotics taken during pregnancy and infancy may reduce the risk and severity of this skin condition in children.
• Pediatric acute infectious diarrhea: Probiotics, particularly LGG and Saccharomyces boulardii, may shorten the duration of acute diarrhea in infants and children by about one day.
• Antibiotic-associated diarrhea: Probiotics might reduce the risk of diarrhea caused by antibiotics in individuals under 65, especially if taken early during antibiotic treatment.
• Inflammatory bowel disease (IBD): Probiotics may slightly reduce symptoms of ulcerative colitis when used alongside medication, but they seem ineffective for Crohn's disease.
• Irritable bowel syndrome (IBS): Probiotics may alleviate symptoms of IBS, though the effects vary by strain and treatment duration.
• Hypercholesterolemia: Some studies indicate that probiotics like Lactobacillus acidophilus may slightly lower cholesterol levels, but findings are inconsistent.
• Obesity: Research on probiotics' impact on body weight and fat is inconclusive, with some studies showing slight reductions and others showing no effect or even weight gain.

SAFETY AND USAGE

Generally, probiotics are safe for healthy individuals, with minor side effects like gas. However, they can pose risks for preterm infants and individuals with compromised immune systems, potentially causing severe infections.

There are no official guidelines for probiotic use in healthy individuals. Those interested in trying probiotics should consult healthcare providers for advice on suitable strains, dosages and usage durations. It's also essential to check product labels for expiration dates and storage instructions, as some probiotics require refrigeration.

For more detailed information on probiotics, visit NIH's website at www.nih.gov.