Probiotic Use Surges as Fiber Intake Stagnates in US Adults and Children

Probiotic supplement use increased 786% among US individuals aged less than 20 years and 287% among adults over a 14-year period, while dietary fiber intake and consumption of foods high in live microbes showed little meaningful improvement, according to an analysis published in Clinical Gastroenterology and Hepatology.¹

Among participants younger than 20 years, probiotic use rose from 0.63% in 2009-2010 to 5.58% in 2021-2023. Among adults aged 20 years and older, use increased from 1.8% to 6.96% during the same period (both P < .001).¹

“We have known that probiotic supplement use is increasing across all ages, but this is the first time we have looked closely at it in relation to other microbiome-focused health behaviors,” lead author Kira L. Newman, MD, PhD, clinical assistant professor of internal medicine at the University of Michigan Medical School, said in a statement.²

“Dietary fiber and fresh produce have well-established health benefits for the gut microbiome,” Newman continued. “However, our findings suggest that people are not making changes to what they eat, even though an increasing number are concerned enough about their microbiome to take a probiotic supplement.”²

Probiotic Use Rose Sharply After 2014

Investigators analyzed serial cross-sectional data from 7 cycles of the National Health and Nutrition Examination Survey conducted from 2009-2010 through August 2021-August 2023. Supplement use was determined through a 30-day recall, with probiotics identified by searching reported supplement ingredients for probiotic bacteria and related terms.¹

The supplement analysis included 62 700 respondents, representing a weighted sample of approximately 242.6 million US residents. Overall, 50.2% reported taking at least 1 dietary supplement during the previous 30 days, and 3.8% reported probiotic use. Probiotic use remained relatively stable through 2013-2014 before rising sharply across age and demographic groups.¹

Dietary recall data were available for 54 776 participants, representing approximately 256.8 million US residents. Investigators categorized foods as having low, medium, or high live-microbe content based on estimated colony-forming units per gram. Approximately 26.3% of participants consumed at least 1 high-microbial-content food during the previous day, while 31.2% consumed only foods classified as low in microbial content.¹

Fiber Intake Remained Below Recommended Levels

Probiotic users consumed an average of 1.35 g more fiber per 1000 kcal than nonusers (P < .001). After adjustment for age, sex, race and ethnicity, and household income, the difference narrowed to 1.12 g per 1000 kcal but remained statistically significant (P < .001). Probiotic use was also associated with greater consumption of foods containing high levels of live microbes.¹

Despite those differences, mean and median fiber intake remained below the 14 g per 1000 kcal benchmark used in the analysis across all groups. Among individuals younger than 20 years, daily fiber intake increased modestly from 7.37 to 7.97 g per 1000 kcal between 2009-2010 and 2021-2023 (P = .0166 for trend). Among adults, intake decreased from 8.52 to 8.26 g per 1000 kcal (P = .009).¹

In adjusted analyses, fiber intake declined by 0.05 g per 1000 kcal annually (P = .001). Average microbial food intake increased by only 0.001 point per year on the study’s 3-point scale (P < .001), indicating a statistically significant but minimal change. The proportion of participants consuming high-microbial-content foods also declined modestly after 2011-2012.¹

The researchers said the divergence may represent a missed opportunity for dietary counseling, particularly if some individuals perceive supplements as an alternative to improving overall diet quality. Foods such as vegetables, fruits, legumes, whole grains, and fermented products may provide fiber and live microbes alongside vitamins, minerals, phytonutrients, and other nutrients not delivered by a probiotic supplement alone.¹˒²

Findings Do Not Establish Dietary Substitution

The investigators cautioned that the cross-sectional design cannot determine whether probiotic use caused changes in dietary behavior or whether consumers intentionally substituted supplements for microbiome-supportive foods. Dietary intake was based on 24-hour recall, supplement use was self-reported, and response rates declined in more recent NHANES cycles.¹

The analysis also did not evaluate clinical outcomes or establish that probiotic supplements and high-microbial-content foods produce equivalent effects on the gut microbiome. The authors noted that any apparent health benefits associated with foods containing live microbes may reflect their broader nutrient content rather than microbial exposure alone.¹

“The increasing probiotic supplement use by adults and children in the US, with a lack of corresponding improvements in diet, highlights a gap in health policy and communication. There is a need for public health interventions to improve the microbial and fiber content of the American diet to promote microbiome health,” concluded investigators. “The role of probiotics in health is important to investigate further but should be considered in the context of overall dietary quality.”¹

References

1. Newman KL, Lee AA, Singh P, et al. Increases in probiotic supplement use exceed microbiome-focused dietary changes in US adults and children. Clin Gastroenterol Hepatol. Published online September 7, 2026. doi:10.1016/j.cgh.2026.08.029
2. Page S. As probiotic use surges, microbiome-supportive food consumption stagnates. News release. Published September 8, 2026. Accessed September 9, 2026. https://www.uofmhealth.org/health-lab/probiotic-use-surges-microbiome-supportive-food-consumption-stagnates