Maltodextrin as a placebo affects gut and body in trials
What it found
In 70 human trials where maltodextrin was given as a placebo, most found changes in gut bacteria, immune markers, or body measurements.
The authors say this calls into question its use as a neutral placebo.
What they found
Studies in people
Effects on body
Some trials found changes in body weight, body mass index, blood pressure, blood sugar, and feelings of fullness after taking maltodextrin. For example, 3.3 grams per day for 16 weeks increased body weight and BMI in overweight children, while 6 grams per day for 15 days decreased these in healthy people.
Gut bacteria changes
Over half of the trials that looked at gut bacteria found changes in types like Firmicutes and Bacteroidetes, and in Lactobacillus and Bifidobacterium. The direction of change varied, with some increases and some decreases.
Microbial metabolites
Some trials found changes in substances produced by gut bacteria, such as short-chain fatty acids and bile acids. For instance, 15 grams per day for 3 weeks increased fecal acetate and propionate in healthy adults.
Immune and gut markers
About a quarter of the trials reported changes in immune markers like immunoglobulins and inflammatory cytokines, and in gut permeability. For example, 12 grams per day increased gut permeability in elderly adults challenged with indomethacin.
Other findings
Justification for placebo
Only 20% of the trials gave a reason for using maltodextrin as a placebo, and 2.9% acknowledged that their data showed it was not inert.
What the authors conclude
“Orally-consumed MDX often (63.9% of RCTs) induces effects on human physiology/gut microbiota. Such effects question the validity of MDX as a placebo-control in human clinical trials.”
Also in their conclusions
- They conclude that orally consumed maltodextrin often induces effects on human physiology and gut microbiota, questioning its validity as a placebo-control in human clinical trials.
- They also question the appropriateness of using maltodextrin as a widely used food additive and highlight the need to reassess its impact on human intestinal health.
How it was done
Maltodextrin is often used as a placebo in human trials, but the authors suspected it might not be inactive because lab and animal studies have shown it can affect the gut.
They looked at 70 randomized placebo-controlled trials in people where maltodextrin was given as a placebo. The trials included various groups, from healthy adults to people with conditions like diabetes, obesity, and celiac disease, and lasted from 1 to 168 days with doses from 0.3 to 42 grams per day.
What it can’t tell you
- This review cannot show that maltodextrin causes any long-term health problems, only that it can cause changes in the short term.
- The studies varied widely in dose, duration, and populations, so it is hard to generalize the findings to all people or all types of maltodextrin.
- The review cannot prove that the changes seen are harmful or beneficial, only that they occurred.
Who paid
- Funding
- Funded by NIDDK NIH HHS (from the PubMed record).
- Conflicts
- Declarations. Conflict of interest On behalf of all authors, the corresponding author states that there is no conflict of interest.
- Authors work at
- Case Western Reserve University, USA; Case Western Reserve University School of Medicine, USA; University Hospitals Cleveland Medical Center, USA
The paper
- Title
- Validity of food additive maltodextrin as placebo and effects on human gut physiology: systematic review of placebo-controlled clinical trials
- Type
- Systematic review
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Almutairi R, Basson AR, Wearsh P, Cominelli F, Rodriguez-Palacios A (2022). Validity of food additive maltodextrin as placebo and effects on human gut physiology: systematic review of placebo-controlled clinical trials. European journal of nutrition. doi:10.1007/s00394-022-02802-5Free full textPubMed 35230477DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error