Surge in Probiotic Use in the US Yet Fiber Intake Remains Low

Dr. Kira Newman, the study's lead author and a clinical assistant professor at the University of Michigan Medical School, states that the data does not clarify how individuals are making their dietary choices. Some probiotic users appear to also have higher fiber and microbially dense food intakes, suggesting a holistic approach to gut health. However, she points out that the differences in dietary habits between probiotic users and non-users are minimal. Most users still do not consume recommended amounts of dietary fiber.

The study found that many probiotic consumers fail to meet fiber intake recommendations, with overall consumption remaining far below the suggested level. It notes a small, statistically significant decrease in fiber intake over time, and while average microbial intake showed a slight increase, it was minimal.

Data from the Clinical Gastroenterology and Hepatology study was drawn from the US National Health and Nutrition Examination Survey, encompassing dietary recall information from 54,776 respondents, representing about 256 million people nationwide. The proportion of individuals under 20 taking probiotic supplements grew from 0.63% to 5.58%, while the percentage for adults over 20 increased from 1.8% to 6.96%.

Despite evidence suggesting that probiotic users generally consume healthier diets, including more high-microbial foods and an average of 1.35 grams more fiber per 1,000 calories than non-users, they still fall short of daily fiber targets. The mean and median fiber intake for all groups remains lower than the recommended intake of 14 grams per 1,000 kilocalories.

The study emphasizes that probiotic supplements are often taken without healthcare provider recommendations. It calls for increased consumption of microbe-diverse fruits, vegetables, and legumes, which provide a variety of fibers essential for gut health. A separate survey published by Rooted Research Collective earlier this year revealed that nearly half of US citizens turn to unaccredited sources, such as social media and AI-generated recommendations, rather than trained nutrition professionals.

According to Innova Market Insights, fiber and probiotics are the most commonly included gut health ingredients, with 38% of food and supplements launched in 2025 claiming to contain fiber and 19% claiming to include probiotics. There is a concern that consumers often do not understand the relationship between probiotics and fiber; beneficial gut bacteria rely on diverse fiber sources for nourishment. Dr. Newman warns that if underlying dietary patterns remain poor, probiotic supplements may have limited health benefits.

She emphasizes that a diet rich in fiber is essential to sustain beneficial bacteria provided by supplements, highlighting the need for broader dietary changes on both individual and systemic levels. In response to these trends, some brands are innovating their products; for example, Momentous has launched a fermentable fiber supplement designed to enhance gut health.

The authors of the study point out that the rise in probiotic supplement usage, contrasted with stagnant dietary improvements, indicates a gap in health policy and public messaging. Dr. Newman advocates for increased governmental support and clearer guidance on the importance of fresh vegetables, fruits, and whole grains.

She argues that a balanced diet supports a diverse array of beneficial gut microbes and that prebiotic supplements lack the variety found in whole foods. The findings of this research aim to spark more public health campaigns focused on the significance of diet in promoting microbiome health.