The History of Probiotics: From Ancient Fermented Foods to Modern Science

People were enjoying the benefits of live microbes for thousands of years before anyone knew bacteria existed. Yogurt, kefir, sauerkraut, kimchi, and fermented milks are some of humanity's oldest foods. Here's how those traditions led to the modern science of probiotics.

Fermented foods: an ancient tradition

Long before refrigeration, fermentation was one of the main ways people preserved food. Milk, vegetables, grains, and fish were fermented across nearly every culture. The International Scientific Association for Probiotics and Prebiotics (ISAPP) notes that these fermented foods were a source of live dietary microbes for most of human history, even though people didn't know the microbes were there.^[1]

The scientist who connected microbes and health

The modern idea of probiotics is usually traced to Élie Metchnikoff (1845–1916), a Russian-born scientist at the Pasteur Institute in Paris who won a Nobel Prize for his work on the immune system.^[2]

In the early 1900s, Metchnikoff noticed that some rural Bulgarians who regularly drank fermented milk seemed to live long lives. He theorized that harmful bacteria in the intestines contributed to aging, and that the lactic acid bacteria in yogurt might counter them.^[1][2] Metchnikoff drank sour milk himself every day, and his ideas helped spark a European craze for Bulgarian yogurt.^[1]

The lactic acid bacterium responsible for Bulgarian yogurt had been identified a few years earlier by a young Bulgarian researcher, Stamen Grigorov. It's known today as Lactobacillus delbrueckii subsp. bulgaricus.

Refining the science

Scientists later discovered that Metchnikoff's "Bulgarian bacillus" could not actually survive in the human intestine.^[1] Researchers then turned to bacteria that could, such as Lactobacillus acidophilus, and the field steadily evolved over the 20th century.^[2]

The word probiotic comes from Greek and means "for life." In 2001, an expert panel convened by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) defined probiotics as live microorganisms that, when given in adequate amounts, provide a health benefit. ISAPP later refined the wording slightly, and this is the definition scientists use today.^[1]

What modern research shows

Probiotics are one of the most actively studied areas in nutrition science. Research suggests that certain strains may support digestive health, but the effects are strain-specific: a benefit shown for one strain does not automatically apply to another.^[1] That's why it's helpful to choose products that clearly list their strains and potency.

For help reading labels, see What Does 40 Billion CFU Actually Mean? and Probiotic Timing: Morning or Night?

How the FDA regulates probiotics

Probiotic supplements are regulated as dietary supplements in the US. Under DSHEA (1994), the FDA does not approve supplements for safety or effectiveness before they are marketed.^[3]

The FDA has also issued an important warning. In October 2023, the agency cautioned health care providers about giving probiotics to preterm infants in hospitals, after reports of serious infections and at least one infant death. The FDA noted that no probiotic product has been approved as a drug for infants.^[4]

Safety notes

• Some people notice mild gas or bloating for the first week or two.
• People with weakened immune systems, serious illness, or a central IV line should talk with their doctor before taking probiotics.
• Probiotics should never be given to premature infants except under a doctor's direction.^[4]

The bottom line

From ancient fermented foods to a Nobel laureate's yogurt theory to today's strain-specific research, probiotics have a fascinating history. The science has come a long way, and it continues to evolve.

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Sources

1. International Scientific Association for Probiotics and Prebiotics. The ISAPP Quick Guide to Probiotics for Health Professionals: History, Efficacy, and Safety.
2. Mackowiak PA. Recycling Metchnikoff: Probiotics, the Intestinal Microbiome and the Quest for Long Life. Front Public Health. 2013.
3. U.S. Food and Drug Administration. Information for Consumers on Using Dietary Supplements.
4. Associated Press. FDA warns about giving probiotics to preterm babies after infant death, injuries. October 26, 2023.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This content is for educational purposes and is not medical advice. Historical and traditional uses are described for context only.