Journal Article 1 Mention
Positive Health Outcomes Associated with Live Microbe Intake from Foods, Including Fermented Foods, Assessed using the NHANES Database
Colin Hill•2023
Daniel Joseph TancrediChristopher J. Cifelli
Top 1% · 99th Percentile
117 citations · Public Health, Environmental and Occupational Health
Open Access

TLDR

Adults who ate more foods containing living organisms tended to have slightly better blood pressure, blood sugar, body size, inflammation, and blood-fat measurements. This study cannot show that these foods caused the improvements.

Summary

1 Study Aim

The authors examined whether eating live dietary microbes (living microorganisms in food) was linked with better health measurements. They tested this relationship for blood pressure, body measurements, inflammation, blood sugar, insulin, and blood fats. They also examined fermented foods separately. Eating more foods with living organisms was linked with slightly better health measurements.

2 Study Design

The researchers conducted a cross-sectional analysis (a health snapshot) using the National Health and Nutrition Examination Survey (NHANES), a representative US health survey. They included 46,091 adults aged 19 years or older from 2001–2018. Experts classified 9,388 food codes by estimated live microbe levels, measured as colony-forming units (CFU), or viable organisms. The researchers used regression models (statistical methods for estimating relationships) and adjusted for demographics, lifestyle, income, and sometimes body mass index (BMI). They analyzed food intake as grams and as three intake groups, while examining fermented foods separately. The study compared eating patterns with health measurements at one point in time, rather than testing a diet intervention.

3 Findings

The study found that each additional 100 grams of medium- or high-microbe foods was associated with lower systolic blood pressure, inflammation marker C-reactive protein, glucose, insulin, triglycerides, waist size, and BMI. High-density lipoprotein (HDL) cholesterol, often called “good” cholesterol, was slightly higher. Low-density lipoprotein and total cholesterol showed no meaningful reductions. Fermented foods showed similar patterns, although links with glucose, insulin, and inflammation were weaker. The authors stress that this observational design cannot establish cause and effect. Other foods or lifestyle patterns may explain some findings. They recommend randomized trials before developing dietary guidance for live microbes. Foods containing living organisms were linked with small improvements across several health measures, but controlled studies must test whether they cause those benefits.

Abstract

Live dietary microbes have been hypothesized to contribute to human health but direct evidence is lacking. This study aimed to determine whether the dietary consumption of live microbes is linked to improved health outcomes. Data from the NHANES 2001–2018 were used to assess microbial intake and their adjusted associations with selected physiological parameters (e.g., blood pressure, anthropometric measures, and biomarkers) among adults aged 19 y and older. Regression models were constructed to assess the microbial intake with each physiological parameter and adjusted for demographics and other covariates. Microbial intake was assessed as both a continuous variable and a 3-level categorical variable. Fermented foods were assessed in a separate model. In continuous models, an additional 100-g intake of microbe–containing foods was associated with a lower systolic blood pressure (regression coefficient: −0.331; 95% CI: −0.447, −0.215 mm Hg), C-reactive protein (−0.013; 95% CI: −0.019, −0.008 mg/dL), plasma glucose −0.347; 95% CI: −0.570, −0.124 mg/dL), plasma insulin (−0.201; 95% CI: −0.304, −0.099 μU/mL), triglyceride (−1.389; 95% CI: −2.672, −0.106 mg/dL), waist circumference (−0.554; 95% CI: −0.679, −0.428 cm), and BMI −0.217; 95% CI: −0.273, −0.160 kg/m2) levels and a higher level of high density lipoprotein cholesterols (0.432; 95% CI: 0.289, 0.574 mg/dL). Patterns were broadly similar when microbial intake was assessed categorically and when fermented foods were assessed separately. To our knowledge, this study is the first to quantify, in a nationally representative data set of American adults and using stable sets of covariates in the regression models, the adjusted associations of dietary intakes of live microbes with a variety of outcomes, such as anthropometric measures, biomarkers, and blood pressure levels. Our findings suggest that foods with higher microbial concentrations are associated with modest health improvements across a range of outcomes.

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