Drinking a specially formulated tomato and soybean juice rich in plant compounds associated with health benefits reduced several markers of inflammation in obese adults after just four weeks, according to a new study.
The findings suggest that this beverage may act as a functional food that helps control chronic inflammation, which contributes to many long-term health conditions.
Researchers found that the juice, which contained high concentrations of lycopene and soy isoflavones, significantly lowered blood levels of three proteins associated with systemic inflammation compared to a control tomato juice that did not contain these compounds.
“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 actually see that this is having an impact on inflammation, rather than just saying something is anti-inflammatory?”
Based on these results and other supporting evidence, Cooperstone and colleagues secured funding from the National Institute of Diabetes and Digestive and Kidney Diseases for a pilot clinical trial to investigate whether the same tomato and soy juices could reduce inflammation in patients with pancreatitis.
This study was recently published in the journal Molecular nutrition and food research.
Why tomatoes and soybeans?
Lycopene is a carotenoid that is responsible for the red color of tomatoes and certain other fruits and vegetables. Soy isoflavones belong to a group of compounds called flavonoids, which can mimic some of the effects of the hormone estrogen. Both are naturally occurring phytochemicals that play important roles in plant health.
The tomato and soy juice used in this study was developed several years ago by researchers at Ohio State after previous studies suggested that diets rich in tomato products or soy were associated with a lower risk of prostate cancer. This juice is made using tomatoes specially bred to contain high levels of lycopene and fortified with soy isoflavone extract.
A subsequent study at Ohio State University found that increased juice intake was associated with lower prostate-specific antigen levels in some men with prostate cancer. Other studies have also shown that tomatoes and soybeans, taken individually or together, can influence inflammatory and metabolic processes associated with obesity and other chronic diseases.
“There was enough convincing evidence that compounds in tomato and soy may modulate inflammation, so we decided to test this in humans,” Cooperstone said.
Human trials show reduced inflammation
Twelve healthy adults with obesity participated in this study. Participants drank two 6-ounce cans of tomato-soy sauce juice every day for four weeks. After a washout period, they consumed low-carotenoid tomato juice for an additional four weeks.
“The hypothesis is that lycopene in tomatoes and isoflavones in soybeans are causing the effect, so we don’t want to use water alone as a control,” Cooperstone said.
The researchers took blood samples every four weeks and measured cytokines, inflammatory proteins produced by the immune system.
Only tomato and soybean juices produced significant reductions in three cytokines, interleukin (IL)-5, IL-12p70, and granulocyte-macrophage colony-stimulating factor (GM-CSF). The researchers also observed a decrease in tumor necrosis factor alpha (TNF-a), but the change did not reach statistical significance.
Changes are seen in areas other than inflammatory markers
The research team also tested participants’ urine samples before and after each stage of the study, looking for changes in metabolites (molecules produced when the body breaks down nutrients and performs essential biological processes).
Changes in metabolites were observed after consuming both tomato and soybean juice and control tomato juice, indicating that tomatoes can produce biological effects even in the absence of high levels of lycopene.
However, changes related to soy isoflavone metabolites were noticeable in participants who consumed tomato-soy juice. Although the researchers say more research is needed, these results provide further evidence that the beverage affects human biology in measurable ways.
“This is probably due to the fact that our intervention is not just these two compounds,” Cooperstone said. “Ultimately, we want to better understand how the foods we eat are related to our health. And if we really want to be sure, we need to test them in clinical trials. And that’s what we’re doing here.”
Potential benefits for pancreatitis patients
The research team also gathered evidence from animal studies suggesting that tomato and soybean juices may reduce inflammation and reduce the severity of chronic pancreatitis.
These findings helped support the initiation of a new clinical trial focused on patients with pancreatitis. Researchers hope the drink will help treat conditions for which there are currently limited treatment options.
“Care for patients with pancreatitis is palliative and focuses on controlling pain and gastrointestinal symptoms. Our hypothesis is that tomato and soybean juice could serve as an intervention to reduce inflammation and hopefully improve the patient’s quality of life,” Cooperstone said.
This research was supported by the U.S. Department of Agriculture, the National Institutes of Health, the Lisa and Dan Wampler Endowed Fellowship for Food and Health Research, and the Ohio Food for Health Initiative.
Co-authors included lead author Maria Chorolla, Jenna Miller, Emma Bilbrey, David Francis, and Thomas Mace of The Ohio State University, and Janet Nabotny of the Department of Agriculture. Mace is the principal investigator on the pancreatitis trial. Cooperstone, Philip Hart and Kristen Roberts of Ohio State University are also principal investigators on the study.
