Research & Your Health is a series of articles written in accessible, everyday language, focused on the latest scientific research of natural health products.
On April 2, 2014
Background: Obesity is a state of chronic low-grade inflammation that promotes the development of cardiovascular disease, diabetes and cancer. Obese individuals show increased levels of circulating inflammatory biomarkers including C-reactive protein, TNF-α, IL-6 and IL-8. The antioxidant lycopene, found in tomatoes, reduces inflammation by lowering the production of those biomarkers and potentially reducing the damaging effects of obesity.
Objective: To see if tomato juice affected the levels of inflammatory biomarkers in overweight and obese females.
Methods: 106 otherwise healthy overweight or obese female university students were randomly divided into two groups. One group was given 110mL of tomato juice to drink with each of their three main meals for 20 days (total daily intake 37 mg lycopene) while the other group was given water. At the start and end of the 20 day study period, subjects’ height and weight were measured and blood samples were drawn to measure their levels of the inflammatory biomarkers.
Results: At the start of the study, the subjects in both groups had similar characteristics, including their levels of biomarkers. However, by the end of the study, the tomato juice group had significantly lower levels of TNF-α and IL-8 compared to baseline and the control group. When the groups were further divided into overweight or obese according to their BMI, the overweight group still had significantly lower levels of TNF-α and IL-8 whereas the obese group had decreased levels of IL-6, with no differences in TNF-α, IL-8 or C-reactive protein.
Conclusion: Tomato juice significantly decreased TNF-α and IL-8 in overweight women; however, obese women showed decreased IL-6 instead. The authors speculate that the difference in response between overweight and obese subjects was that the anti-inflammatory actions of the tomato juice were not potent enough to dampen the heightened level of baseline inflammation in the obese group. Alternatively, the small number of obese (19) vs overweight (85) subjects could have been too few to accurately detect changes.
The Findings in Perspective: This is the first study to show that tomato juice reduces inflammation biomarkers in overweight and obese females, although it agrees with previous studies in men. The anti-inflammatory effect of tomato juice is likely due to lycopene, although tomato juice also contains other important nutrients such as beta-carotene and vitamin C. For the full study abstract, please click here.