Obesity is a frequent topic. And there has considerable discussion about various ways of managing eating in order to help control weight. Of these, one of the most discussed in recent years has been intermittent fasting and variations.
In that context, several times members have asked about the relationship between thyroid hormones and intermittent fasting. We have had few solid items of research to quote. Now, a new paper, discussing this exact area is available.
Review Article
Diabetes, Obesity and Metabolism
Endocrinology and Metabolism 2021;36(4):745-756.
Published online: August 27, 2021
DOI: doi.org/10.3803/EnM.2021.405
Effects of Intermittent Fasting on the Circulating Levels and Circadian Rhythms of Hormones
Bo Hye Kim1,2, Yena Joo3, Min-Seon Kim4, Han Kyoung Choe5, Qingchun Tong6, Obin Kwon1,2,7
1 Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea
2 Genomic Medicine Institute, Medical Research Center, Seoul National University, Seoul, Korea
3 Seoul National University College of Medicine, Seoul, Korea
4 Division of Endocrinology and Metabolism, Department of Internal Medicine, Diabetes Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
5 Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
6 Brown Institute of Molecular Medicine and Department of Neurobiology and Anatomy, McGovern Medical School of UTHealth, and MD Anderson Cancer Center & UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
7 Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
Abstract
Intermittent fasting has become an increasingly popular strategy in losing weight and associated reduction in obesity-related medical complications. Overwhelming studies support metabolic improvements from intermittent fasting in blood glucose levels, cardiac and brain function, and other health benefits, in addition to weight loss. However, concerns have also been raised on side effects including muscle loss, ketosis, and electrolyte imbalance. Of particular concern, the effect of intermittent fasting on hormonal circadian rhythms has received little attention. Given the known importance of circadian hormonal changes to normal physiology, potential detrimental effects by dysregulation of hormonal changes deserve careful discussions. In this review, we describe the changes in circadian rhythms of hormones caused by intermittent fasting. We covered major hormones commonly pathophysiologically involved in clinical endocrinology, including insulin, thyroid hormones, and glucocorticoids. Given that intermittent fasting could alter both the level and frequency of hormone secretion, decisions on practicing intermittent fasting should take more considerations on potential detrimental consequences versus beneficial effects pertaining to individual health conditions.
Keywords: Intermittent fasting; Circadian rhythm; Insulin; Thyroid hormones; Glucocorticoids
Full paper freely accessible here: