Written by Joyce Smith, BS. Study authors attribute the blood pressure- and cholesterol-lowering effects of tart cherry juice consumption to specific biomarkers of inflammation and oxidative stress.
Cardiovascular disease (CVD), diabetes and cancer are the leading causes of death and disability in the U.S., and are often linked to underlying inflammation and oxidative stress. Extensive research has extolled the health benefits of fruit and vegetable-rich diets to lower the risk of CVD and death 1. The polyphenolic compounds, fiber, carotenoids, and certain vitamins and minerals such as vitamin C and potassium, abundant in many fruits 2, have been attributed to the reduced risk of chronic diseases. Fruits are a rich source of polyphenolic compounds, especially proanthocyanins, anthocyanins, and flavonols, all of which are strong antioxidants 3. Their anti-inflammatory and antioxidant properties have been demonstrated in both in vivo and in vitro studies 4. These beneficial effects are thought to be related to anthocyanins, the naturally-occurring plant pigments that give tart cherries their ruby-red color and sour-sweet taste and may be responsible for their health-promoting properties. Chai and colleagues, in a 2018 study on Montmorency tart cherries (Prunus cerasus L.- the most common varietal grown in the U.S.), found that daily consumption of tart cherry juice lowered systolic blood pressure and low density lipoproteins (LDL) cholesterol in older adults and suggested its daily use as an intervention for improved cardiovascular health for this population 5. The following study builds upon their previous work.
To understand the underlying mechanisms through which tart cherry juice reduces systolic BP and LDL cholesterol, several blood biomarkers of inflammation and oxidative stress were assessed in the present study. The Chai team hypothesized that the cardioprotective effects of tart cherry juice occur through its anti-inflammatory and anti-oxidative properties. In a randomized placebo-controlled clinical trial 6, 17 men and 20 women (aged 65-80) were randomized to consume 240 mL of chart cherry juice twice daily for 12 weeks. Anthropometric, dietary and physical activity assessments were collected at baseline and at the end of 12 weeks. Three-day food diaries were collected and fasting blood was drawn at baseline and at 12 weeks for inflammatory and oxidative stress biomarkers.
Over the 12-week period, physical activity levels significantly decreased in both the cherry and control groups (p<0.0001); however, dietary cholesterol significantly increased in both groups (p<0.001) and p=0.04) respectively. With respect to biomarkers of inflammation and oxidative stress, 8-oxoguanine glycosylase (OGG1), C-reactive protein (CRP), and oxidized LDL cholesterol (OxLDL) were all similar at baseline. However, while DNA repair activity of OGG1 increased (p<0.0001), plasma CRP (p=0.03), malondialdehyde (MDA, p=0.03) and OxLDL (p=0.07) decreased in the in the tart cherry group compared to control. Within group analysis revealed that plasma levels of CRP, MDA, and OxLDL decreased numerically by 25%, 3%, and 11%, respectively compared to their corresponding baseline values.
Other measured inflammatory and oxidative stress biomarkers and nitric oxide (NO) all had similar baseline levels in both the tart cherry and control groups and did not change significantly over the twelve-week period. Results remained significant after adjusting for baseline physical activity, and dietary cholesterol.
Study results suggest that regular tart cherry juice consumption helps reduce CVD risk factors in older adults by reducing systolic BP and LDL cholesterol 5. Both effects may be the byproduct of the anti-oxidative and anti-inflammatory properties of tart cherry juice, as evidenced by an increase in the plasma levels of DNA repair activity of OGG1 and a reduction in CRP levels compared to control. A diet rich in fruits and vegetables may offer significant benefits to those with a cardiovascular risk profile. Additional longer -term studies of larger and older populations are warranted.
Source: Chai, Sheau C., Kristina Davis, Zugui Zhang, Longying Zha, and Kenneth F. Kirschner. “Effects of tart cherry juice on biomarkers of inflammation and oxidative stress in older adults.” Nutrients 11, no. 2 (2019): 228.
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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Posted January 26, 2021.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
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