Sugar and inflammation in the body
What it found
High sugar intake is linked to low-grade chronic inflammation and autoimmune diseases, but most of the evidence comes from animal studies.
Some human trials found no change in inflammation markers after eating fructose, glucose or high fructose corn syrup.
What they found
Studies in people
Inflammation markers in people
Some human trials found that fructose, glucose and sucrose increased blood lipid and hs-CRP levels, with fructose and sucrose having a stronger effect than glucose. But other trials found no significant changes in hs-CRP and IL-6 after consuming fructose, glucose or HFCS for 8 days or 12 weeks.
Rheumatoid arthritis
Women who drank sugar-sweetened beverages daily had an increased risk of seropositive rheumatoid arthritis compared with women who did not drink them, with a greater risk among women over 55. High sugar intake may alter gut bacteria and affect inflammatory pathways.
Animal and lab studies
Multiple sclerosis
In a mouse model of multiple sclerosis, high-glucose and high-sucrose diets worsened disease progression and increased neuroinflammation. The effect may work by increasing Th17 cells or by changing gut bacteria.
Psoriasis
In mice, a Western diet activated the IL-23 signaling pathway and increased IL-17A production before the mice gained weight, which worsened skin inflammation. Switching mice back to a standard diet reduced skin inflammation and partly reversed gut bacteria changes.
Studies in people and animals
Low-grade chronic inflammation
Excessive sugar intake can cause metabolic disorders and increase inflammatory mediators and pro-inflammatory cytokines in various tissues, leading to insulin resistance and low-grade chronic inflammation. This may be partly why high sugar intake is linked to chronic disease risk.
Inflammatory bowel disease
About 10% of people with IBD believe sugary foods trigger flare-ups. Some prospective studies found that HFCS and sugar-sweetened beverages were linked to higher IBD risk, and mouse studies show high glucose changes gut bacteria and increases inflammatory cytokines.
What the authors conclude
“Based on these reported findings, we emphasize that dietary sugars and mixed processed foods may be a key factor leading to the occurrence and aggravation of inflammation.”
Also in their conclusions
- They emphasize that dietary sugars and mixed processed foods may be a key factor leading to the occurrence and aggravation of inflammation.
- They conclude that revealing the roles of excessive hexose intake in human inflammatory diseases are fundamental questions that need to be solved urgently.
- They advise that close attention should be paid to the combination of high glucose-mediated immune imbalance and tumor development.
How it was done
The authors wanted to understand how excessive sugar intake affects inflammation, since the impact of dietary sugars on inflammatory diseases was previously unknown.
They reviewed studies on the effects of high sugar intake on low-grade chronic inflammation, rheumatoid arthritis, multiple sclerosis, psoriasis and inflammatory bowel disease. The studies included human trials, animal experiments and cell research.
What it can’t tell you
- Most of the studies were performed with mouse models, limiting the clinical applicability of these findings.
- Human trials show mixed results, so it is not clear whether sugar causes inflammation in people.
- The review cannot show cause and effect, only associations and mechanisms from different types of studies.
Who paid
- Conflicts
- The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
- Authors work at
- Sichuan University, China; The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, China
The paper
- Title
- Excessive intake of sugar: An accomplice of inflammation
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Ma X, Nan F, Liang H, et al (2022). Excessive intake of sugar: An accomplice of inflammation. Frontiers in immunology. doi:10.3389/fimmu.2022.988481Free full textPubMed 36119103DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error