Nutrition Bytes: May 2022

Quercetin Supplement Reduces Inflammation and Pain in Rheumatoid Arthritis

A recent study published in the Journal of the American College of Nutrition1 found that quercetin supplementation reduced inflammation and improved disease severity and quality of life in women with rheumatoid arthritis (RA). In this double-blind, randomized clinical trial, 50 women aged 19 to 70 years with diagnosed RA supplemented with 500 mg of quercetin per day or placebo for eight weeks. Since women are two to three times more likely than men to suffer from RA, they were selected as subjects of this study. At the beginning and end of the intervention, rheumatologists assessed the subjects for disease activity and severity, and blood samples were taken to analyze inflammation markers like tumor necrosis factor alpha (TNF-a). Subjects also completed a series of questionnaires to measure changes in clinical symptoms and overall wellbeing.

Woman with wrist painResults revealed that compared to placebo, eight weeks of quercetin supplementation significantly reduced TNF-a levels and relieved symptoms such as early morning stiffness and morning- and post-activity pain. Quercetin also enhanced the subjects’ quality of life, including their ability to dress, stand up, walk, and grip. Most profoundly, disease activity scores were greatly improved, with many of the subjects no longer having signs of active disease following the intervention.

This is just one example of research that demonstrates quercetin’s ability to help with chronic inflammation-related conditions, particularly through its antioxidant and anti-inflammatory effects. Most studies show a benefit of quercetin at 500-1,000 mg/day. While quercetin is a flavonoid that is ubiquitously present in fruits and vegetables, it can be hard to get this amount through diet alone. Quercetin supplements help support optimal levels of this important nutrient.

Large Percentage of Adults Have Inadequate Intakes of Important Immune Nutrients

A recent review published in the journal Nutrients2 revealed that a startling number of Americans are falling short in consuming nutrients that are critical for maintaining healthy immune function, but dietary supplements can help fill those gaps. The results of the review showed that 95% of American adults had an inadequate intake of vitamin D and 84% had an inadequate intake of vitamin E. Furthermore, inadequate intake was 45%, 46%, and 15% for vitamin A, vitamin C, and zinc, respectively. Researchers studied these nutrients specifically due to their essential roles in immune function.

Bowl of vitamins and supplementsThe review analyzed data from the National Health and Nutrition Examination Survey (NHANES), a cross-sectional study of the U.S. population, including 26,282 adults aged 19 to 99 years, conducted by the Centers for Disease Control and Prevention (CDC) every other year. While a healthy, nutrient-dense diet is the foundational first step for consuming necessary nutrients, this research elucidates that Americans are not eating the foods necessary to meet our nutritional needs. Because vitamins A, E, D, C, and zinc are crucial for the immune system’s ability to fight off foreign invaders, we must be mindful of how we nourish our bodies, beginning with a healthy diet and supplementing the rest.


  1. Fatemeh Javadi MSc, Arman Ahmadzadeh MD, Shahryar Eghtesadi PhD, Naheed Aryaeian PhD, Mozhdeh Zabihiyeganeh MD, Abbas Rahimi Foroushani PhD & Shima Jazayeri MD, PhD (2016): “The Effect of Quercetin on Inflammatory Factors and Clinical Symptoms in Women with Rheumatoid Arthritis: A Double-Blind, Randomized Controlled Trial,” Journal of the American College of Nutrition, DOI: 10.1080/07315724.2016.1140093
  2. Reider CA, Chung RY, Devarshi PP, Grant RW, Hazels Mitmesser S. “Inadequacy of Immune Health Nutrients: Intakes in US Adults, the 2005-2016 NHANES.” Nutrients. 2020;12(6):1735. Published 2020 Jun 10. doi:10.3390/nu12061735