Can Too Much Antioxidants Be Bad for You?

Antioxidants: Balancing Benefits and Risks

Dear Dr. Mahler: Is there such a thing as too much anti-oxidants and anti-inflammatory supplements for we COPD patients? I ask because I have recently been diagnosed with moderate COPD, and actually returned a bottle of concentrated tart cherry recommended by a local health food store after reading several articles. Thank you for your time and consideration in responding. William from Oak Brook, IL Dear William: Thanks for an interesting and challenging question. I’ll start by stating that I don’t have a definite answer for you. However, I searched recent published articles in PubMed and provide the following comments after providing general information for other readers. What is Oxidative Stress? This is a natural process that occurs in everyone and damages cells in the body. Oxidative stress is thought to contribute to aging and has been implicated in numerous diseases including hardening of the arteries (atherosclerosis), diabetes, and cancer. There is growing evidence of the role of oxidative stress in those with COPD. Cigarette smoke is a potent source of inhaled oxidants and free radicals present in both the gas and tar phases of the smoke. In COPD the number of inflammatory (redness and swelling) cells are increased in the breathing tubes (airways) and air sacs (alveoli). These inflammatory cells produce reactive oxidative species, a major oxidant that damages and destroys cells. What are Antioxidants? Our body has a wide number of natural antioxidants that protect against oxidative stress. However, when the number of oxidants is greater than available antioxidant defenses, there is damage to cells. Many individuals consume herbs and foods that are antioxidants in an attempt to reduce oxidative stress and cell injury. On June 11, 2015, I posted a response to a question from someone about drinking herbal tea which has antioxidant properties. On February 27, 2017, I posted information on a study that showed that eating fruits and vegetables can prevent or reduce the risk of developing COPD. 2017 Articles about Oxidative Stress and Antioxidants      1. An  article in the February 2017 issue of the journal Scandinavian Journal of Immunology (volume 85; pages 130-137) reported that patients with very severe COPD had higher levels of markers of oxidative stress compared those with mild, moderate, and severe disease.                                                           
N-acetyl cysteine is one of many antioxidants

N-acetyl cysteine has antioxidant and anti-inflammatory effects

 2.  N-acetylcysteine (NAC) is an antioxidant with anti-inflammatory effects available in a capsule. An analysis of 12 studies involving a total of 2,691 patients with COPD showed that long-term (at least 6 months or longer) use of NAC reduced the frequency of flare-ups (exacerbations) with no change in results of breathing tests. This review was published in the March-April 2017 issue of the journal HeartLung (volume 46; pages 120-128).                                                                                                       3. The RESTORE study compared the effects of erdosteine (a pill that thins mucus and is an antioxidant) and placebo in 445 patients with COPD for one year. Erdosteine reduced mild flare-ups (exacerbations) by 19% compared with placebo, but had no effect on moderate or severe flare-ups. A mild flare-up is one when the patient uses more albuterol as rescue therapy, while a moderate flare-up is one when treated with an antibiotic and/or prednisone. In addition, erdosteine reduced the number of days of flare-up symptoms by 25%. This study was published on-line October 12, 2017, in the European Respiratory Journal.   Antioxidants and Cancer William – Thanks for sending the links to articles about the potential harm of antioxidants making cancer worse. Please note that these studies were performed in mice, and it always hard to apply such results to humans. 
Blueberries are rich in antioxidants

Blueberries are rich in antioxidants

My advice is to eat lots of fruits, vegetables, and nuts which are heart healthy foods and also rich in antioxidants. Taking supplements with antioxidants such as concentrated tart cherry is entirely up to you. I am not aware of any studies to provide guidance. Based on the results in mice, I recommend against antioxidant supplements in someone who has cancer. Best wishes on a healthy life, Donald A. Mahler, M.D.

Donald A. Mahler, M.D. is Emeritus Professor of Medicine at Geisel School of Medicine at Dartmouth in Hanover, New Hampshire. He works as a pulmonary physician at Valley Regional Hospital in Claremont, NH, where he is Director of Respiratory Services.