Even with modern medicine, infections caused by bacteria and viruses remain a leading cause of death worldwide.
Scientists are now exploring whether diet may play a role in shaping the body’s response to these threats. A research team led by Ina Bergheim from the Department of Nutritional Sciences at the University of Vienna has shown for the first time that consuming fructose causes monocytes, key immune cells in the blood, to respond more strongly to bacterial toxins in a harmful way. The study found that fructose increases the number of receptors that detect these toxins, which can intensify inflammation. The findings were published in the journal Redox Biology.
How Fructose and Glucose Affect Immune Responses
To examine how different sugars influence the immune system, researchers carried out two randomized studies involving healthy adults. Participants consumed beverages sweetened with fructose or glucose, allowing the scientists to compare how each sugar affected immune activity. Alongside these human studies, the team also performed experiments using isolated monocytes and cell culture models to better understand the biological processes involved.
Fructose Raises Receptors That Detect Bacterial Toxins
The researchers found that fructose intake, unlike glucose, increased the levels of Toll-like receptor 2 in monocytes. Toll-like receptor 2 plays an important role in regulating immune responses. As the concentration of this receptor rose, monocytes became more sensitive to lipoteichoic acid, a toxin produced by certain bacteria.
“The concentration of receptors for such toxins in the body increased, which means that the inflammatory response increased,” explains study leader Ina Bergheim from the University of Vienna. The heightened sensitivity also led to greater release of pro-inflammatory messengers, including interleukin-6, interleukin-1β, and tumour necrosis factor-alpha.
“These findings make an important contribution to understanding how individual food components and fructose in particular can influence the immune system,” says Bergheim. “They indicate that even short-term, high fructose consumption in healthy people can influence the immune system and increase inflammation.”
Implications for Metabolic Health and Future Research
The researchers emphasize that further studies are needed to determine how long-term, consistently high fructose intake may affect immune function and vulnerability to infection. This is especially important for people in higher-risk groups, such as those with type II diabetes mellitus or fatty liver disease, which is associated with metabolic dysfunction.
“Sugar, especially the fructose in sugary drinks and sweets, has long been suspected of increasing the risk of developing metabolic diseases – this needs to be investigated,” says Bergheim.
Reference: “Fructose intake enhances lipoteichoic acid-mediated immune response in monocytes of healthy humans” by Raphaela Staltner, Katja Csarmann, Amelie Geyer, Anika Nier, Anja Baumann and Ina Bergheim, 12 June 2025, Redox Biology.
DOI: 10.1016/j.redox.2025.103729
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6 Comments
Inflammation is known to stimulate the release of xanthine oxidase which breaks purines down into uric acid and free radicals. Unlike glucose, fructose (even from fresh fruit) is known to raise the serum level of uric acid, unregulated. Long-term, inflammation is probably single most common denominator among all now epidemic chronic diseases, from Alzheimer’s and AMD to stroke and suicide. Brilliant, let’s kill more people with chronic inflammation, which already accounts for about 90% to 95% of all cause mortality in the US, to save more of the 3% to 5% who still die from infectious diseases (CDC/NCHS/NVSS, 2019). A better solution would be to have the FDA enforce the Federal Food Drugs and Cosmetics Act (FFDCA, “prohibited acts”) to ensure we all have as natural, pure and safe commercially prepared foods as possible.
Interesting article.
We vacationed in Canada this past summer for a week. No HFCS, my psoriasis nearly vanished! Upon return coworkers were stunned. We’re being poisoned.
Only cancer cells can use fructose for energy. The liver can convert fructose to fat using the same chemical process as it uses to metabolize alcohol resulting in the same damage to the liver as alcohol.
Your food and drinks are spiked with this stuff, it should be illegal to put it in food and drinks.
It is known to cause fatty liver disease and implicated in diabetes type II.
Inb4 influencers use this to say that fruits are bad for you.
Fructose is fruit sugar. So, if I eat an apple, I’m gonna die?
More diet bulls***.