Dietary Antioxidants in the Treatment of Male Infertility: Counteracting Oxidative Stress

Simple Summary: The present review is a comprehensive description of reactive oxygen species (ROS's) different sources, the re-productive consequences of excessive ROS and oxidative stress, and the possible treatments of ROS imbalances through antioxidant intake, foods, and dietary patterns to im-prove male infertility. In summary here we describe that some antioxidants, especially selenium and zinc, omega-3 fatty acids, CoQ10 and carnitines, have been positively related to sperm quality and therefore can help improving male sperm quality and fertility. However, excessive use of antioxidants may be detrimental to the spermatic function and many of the over-the-counter supplements are not scientifically proven to improve fertility. A long term and innocuous solution could be a balanced diet, as it takes advantage of the synergy of multiple antioxidants. Infertility affects about 15% of the population and male factors only are responsible for similar to 25-30% of cases of infertility. Currently, the etiology of suboptimal semen quality is poorly understood, and many environmental and genetic factors, including oxidative stress, have been implicated. Oxidative stress is an imbalance between the production of free radicals, or reactive oxygen species (ROS), and the capacity of the body to counteract their harmful effects through neutralization by antioxidants. The purpose of this review, by employing the joint expertise of international researchers specialized in nutrition and male fertility areas, is to update the knowledge about the reproductive consequences of excessive ROS concentrations and oxidative stress on the semen quality and Assisted Reproduction Techniques (ART) clinical outcomes, to discuss the role of antioxidants in fertility outcomes, and finally to discuss why foods and dietary patterns are more innocuous long term solution for ameliorating oxidative stress and therefore semen quality results and ART fertility outcomes. Since this is a narrative review and not a systematic/meta-analysis, the summarized information in the present study should be considered cautiously.