“Anti-inflammatory” has become one of the most common promises in the wellness aisle, appearing on everything from juices and powders to snack bars and supplements. But what does it take to test whether a food actually affects inflammation in the body?
A small clinical trial from Ohio State University offers one example. Researchers found that a specially developed tomato-soy juice lowered several inflammation-related proteins in healthy adults with obesity after four weeks. The findings are early and limited, but they suggest the drink may affect biological pathways tied to inflammation, a process involved in many chronic conditions.
The study, published in Molecular Nutrition & Food Research, included 12 adults with obesity. Each participant drank two 6-ounce cans of tomato-soy juice daily for four weeks. After a washout period, they drank a control tomato juice for another four weeks. The control juice was designed to be similar, but it had low levels of carotenoids and no soy isoflavones.
“The idea is, can we use food-based interventions to modulate inflammation?” said lead author Jessica Cooperstone, associate professor of horticulture and crop science at The Ohio State University. “And can we test this in a rigorous way so that we can really see this is affecting inflammation, versus just saying something is anti-inflammatory?”
That distinction matters. The tomato-soy juice was not a grocery-store tomato juice with soy added at home. It was developed by Ohio State researchers using tomatoes with a high concentration of lycopene and enriched with soy isoflavone extract. Lycopene is a plant compound that gives tomatoes their red color, while soy isoflavones are plant compounds that can act somewhat like estrogen in the body.
Both compounds have been studied for their potential antioxidant and anti-inflammatory effects. Previous research has linked diets higher in tomato products or soy foods with certain health benefits, and Ohio State researchers have studied the tomato-soy combination before in relation to prostate cancer markers. For this study, the researchers wanted to look more directly at inflammation.
Blood samples taken before and after each intervention showed that the tomato-soy juice significantly lowered three cytokines, which are proteins involved in immune signaling and inflammation. Those proteins were interleukin-5, interleukin-12p70 and granulocyte-macrophage colony-stimulating factor. Another marker, tumor necrosis factor alpha, trended downward but was not statistically significant.
The researchers also analyzed urine samples to look for changes in metabolites, the small molecules produced as the body breaks down foods and carries out normal biochemical processes. Both the tomato-soy juice and control tomato juice appeared to influence some metabolite patterns, suggesting that tomatoes may have effects beyond lycopene alone. The tomato-soy juice also produced changes linked to soy isoflavone metabolism.
“This is probably a function of the fact that there’s more to our intervention agents than just these two compounds,” Cooperstone said. “Ultimately, we want to have a better understanding of how the foods that we eat are relating to our health. And when we really want to be sure, we need to test them in clinical trials. And that’s what we’re doing here.”
The findings show how a functional food claim can be studied more carefully. Rather than assuming certain foods are “anti-inflammatory” because they contain popular plant compounds, the researchers tested the food in people, compared it with a control drink and measured biological changes.
The team is now taking the research a step further. Based on these findings and related animal research, Cooperstone and colleagues have received National Institute of Diabetes and Digestive and Kidney Diseases funding for a pilot clinical trial testing whether the same tomato-soy juice may reduce inflammation in people with pancreatitis.
“Care for patients with pancreatitis is palliative, focused on controlling pain and GI symptoms. Our hypothesis is that the tomato-soy juice may serve as an intervention to decrease inflammation and hopefully increase patients’ quality of life,” Cooperstone said.
For now, the study adds to growing interest in how whole foods and food combinations may influence inflammation. But it also shows why functional food research needs careful testing before wellness claims make the leap from promising to proven.
This work was supported by the U.S. Department of Agriculture, the National Institutes of Health, the Lisa and Dan Wampler Endowed Fellowship for Foods and Health Research, and the Foods for Health Initiative at Ohio State University.