Leo Sher- James J. Peters Veterans’ Administration Medical Center and Icahn School of Medicine at Mount Sinai, New York, NY, United States
A commentary on
Vitamin D Deficiency Associated with Cognitive Functioning in Psychotic Disorders
by Nerhus M, Berg AO, Simonsen C, Haram M, Haatveit B, Dahl SR, et al. J Clin Psychiatry (2017) 78(7):e750–7. doi: 10.4088/JCP.16m10880
I read with interest the paper entitled, “Vitamin D deficiency associated with cognitive functioning in psychotic disorders” that was recently published in the Journal of Clinical Psychiatry (1). The authors found that vitamin D deficiency affects cognitive function. Vitamin D deficiency was significantly associated with decreased processing speed and decreased fluency.
The observation of the authors of this study is consistent with previous reports suggesting that low serum vitamin D levels may be associated with dementia and other forms of cognitive impairment (2, 3). I would like to expand on this subject.
About 90% of vitamin D is produced in the skin from 7-dehydrocholesterol as a result of sunlight exposure (solar ultraviolet B radiation; 290–315 nm) (4). Most cells in the human body have a vitamin D receptor, and, therefore, vitamin D affects many biological pathways (4).
Inadequate sunlight exposure, often associated with a low dietary intake of vitamin D leads to rickets, a disease involving mostly infants and young children (5, 6). A history of research on rickets is long and interesting. Evidence of vitamin D deficiency in children, such as leg deformities, has been noted in the writings of Soranus of Ephesus and Galen (Claudius Galenus) (both second century CE) (5). In 1645, David Whistler, an English medical student, provided the first scientific description of the signs and symptoms of rickets (5, 6). In the twentieth century, the linking of the knowledge that photosynthesized vitamin D and vitamin D in food were similar was responsible for the defeat of rickets (6).
Studies have shown that light exposure improves cognitive performance and alertness (7, 8). Light can optimize brain function during specific cognitive tasks.
Studies suggest that vitamin D may increase the production of testosterone (9, 10). For example, a significant increase in total testosterone levels, bioactive testosterone, and free testosterone levels was noticed in the vitamin D supplemented men (9). A recent prospective study of a relatively large group of men also showed an increase in blood testosterone levels in individuals who received vitamin D (10). Positive associations between vitamin D and testosterone blood levels were observed by several research groups (11, 12).
Several observations indicate that testosterone supplementation may improve cognitive function (13, 14). For example, one study showed that testosterone replacement therapy led to improvement in attention capacity and psychomotor speed (13). Another study suggests that testosterone replacement therapy improves cognitive performance and mood in men with testosterone deficiency syndrome (14).
These observations suggest that vitamin D and testosterone may partially mediate the cognition-enhancing effect of light in some individuals. Can a combination of light therapy, vitamin D, and testosterone supplementation leads to a significant improvement in cognitive functioning? Further studies of this interesting subject are merited.
Author Contributions
The author confirms being the sole contributor of this work and approved it for publication.
Conflict of Interest Statement
The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
References
1. Nerhus M, Berg AO, Simonsen C, Haram M, Haatveit B, Dahl SR, et al. Vitamin D deficiency associated with cognitive functioning in psychotic disorders. J Clin Psychiatry (2017) 78(7):e750–7. doi:10.4088/JCP.16m10880
2. Goodwill AM, Szoeke C. A systematic review and meta-analysis of the effect of low vitamin D on cognition. J Am Geriatr Soc (2017) 65(10):2161–8. doi:10.1111/jgs.15012
3. Dickens AP, Lang IA, Langa KM, Kos K, Llewellyn DJ. Vitamin D, cognitive dysfunction and dementia in older adults. CNS Drugs (2011) 25(8):629–39. doi:10.2165/11593080-000000000-00000
4. Wacker M, Holick MF. Sunlight and vitamin D: a global perspective for health. Dermatoendocrinol (2013) 5(1):51–108. doi:10.4161/derm.24494
5. Zhang M, Shen F, Petryk A, Tang J, Chen X, Sergi C. “English disease”: historical notes on rickets, the bone-lung link and child neglect issues. Nutrients (2016) 8(11):E722. doi:10.3390/nu8110722
6. Rajakumar K. Vitamin D, cod-liver oil, sunlight, and rickets: a historical perspective. Pediatrics (2003) 112(2):e132–5. doi:10.1542/peds.112.2.e132
7. Chellappa SL, Gordijn MC, Cajochen C. Can light make us bright? Effects of light on cognition and sleep. Prog Brain Res (2011) 190:119–33. doi:10.1016/B978-0-444-53817-8.00007-4
8. Vandewalle G, Balteau E, Phillips C, Degueldre C, Moreau V, Sterpenich V, et al. Daytime light exposure dynamically enhances brain responses. Curr Biol (2006) 16(16):1616–21. doi:10.1016/j.cub.2006.06.031
9. Pilz S, Frisch S, Koertke H, Kuhn J, Dreier J, Obermayer-Pietsch B, et al. Effect of vitamin D supplementation on testosterone levels in men. Horm Metab Res (2011) 43(3):223–5. doi:10.1055/s-0030-1269854
10. Canguven O, Talib RA, El Ansari W, Yassin DJ, Al Naimi A. Vitamin D treatment improves levels of sexual hormones, metabolic parameters and erectile function in middle-aged vitamin D deficient men. Aging Male (2017) 20(1):9–16. doi:10.1080/13685538.2016.1271783
11. Nimptsch K, Platz EA, Willett WC, Giovannucci E. Association between plasma 25-OH vitamin D and testosterone levels in men. Clin Endocrinol (Oxf) (2012) 77(1):106–12. doi:10.1111/j.1365-2265.2012.04332.x
12. Wehr E, Pilz S, Boehm BO, März W, Obermayer-Pietsch B. Association of vitamin D status with serum androgen levels in men. Clin Endocrinol (Oxf) (2010) 73(2):243–8. doi:10.1111/j.1365-2265.2009.03777.x
13. Lašaitė L, Čeponis J, Preikša RT, Žilaitienė B. Effects of two-year testosterone replacement therapy on cognition, emotions and quality of life in young and middle-aged hypogonadal men. Andrologia (2017) 49(3). doi:10.1111/and.12633
Keywords: vitamin D, cognition, psychotic, light, testosterone
Citation: Sher L (2017) Commentary: Vitamin D Deficiency Associated with Cognitive Functioning in Psychotic Disorders. Front. Public Health 5:351. doi: 10.3389/fpubh.2017.00351
Received: 24 November 2017; Accepted: 11 December 2017;
Published: 21 December 2017
Edited by:
Frederick Robert Carrick, Bedfordshire Centre for Mental Health Research in Association with University of Cambridge, United KingdomReviewed by:
Consolato Sergi, University of Alberta Hospital, CanadaCopyright: © 2017 Sher. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Leo Sher, leo.sher@mssm.edu, drleosher@gmail.com