The Pleiotropic Effects of Sunlight

With summer right around the corner, huge kiosks of sunscreen are on display at stores everywhere, reminding us to fear the sun. We’ve been told for years that sunlight is something to guard against - and, of course, most of us know someone who’s had a suspicious mole removed. But we also know the sun is needed for vitamin D production - plus, it just feels great on our skin! And obviously our ancestors weren’t slathering on Coppertone when they left the cave.

It seems to be a no-win situation until you learn the facts about sunlight. NBT Scientific Director Megan Hall is with me today to talk about the critical role of sunlight for health and wellness. She outlines the many benefits of sun exposure that go far beyond vitamin D production and sets the record straight on UVA vs UVB rays, skin cancer, and how sunscreen is actually working against you. Here’s the outline of this interview with Megan Hall:

[00:00:11] Megan's new puppy.

[00:03:35] Podcast w/ Kira Furie: Breaking Through the Diet Culture: Medical Care for Every Size.

[00:05:42] Vitamin D and conditions associated with low levels.

[00:07:40] Book: Hidden Valley Road: Inside the Mind of an American Family, by Robert Kolker.

[00:08:22] Optimal Levels and dosing of Vitamin D.

[00:12:55] Vitamin D Calculator.

[00:13:47] COVID-19 and Vitamin D; Studies: 1. Glicio, El James. "Vitamin D Level of Mild and Severe Elderly Cases of COVID-19: A Preliminary Report." Available at SSRN 3593258 (2020); 2. De Smet, Dieter, et al. "Vitamin D deficiency as risk factor for severe COVID-19: a convergence of two pandemics." medRxiv (2020); 3. D’Avolio, Antonio, et al. "25-hydroxyvitamin D concentrations are lower in patients with positive PCR for SARS-CoV-2." Nutrients 12.5 (2020): 1359; 4. Meltzer, David O., et al. "Association of Vitamin D Deficiency and Treatment with COVID-19 Incidence." medRxiv (2020).

[00:15:20] Vitamin D and ACE2.

[00:17:46] Benefits of sunshine beyond vitamin D.

[00:18:01] Circadian rhythm.

[00:18:29] Satchin Panda; Podcast: How to Use Time-Restricted Eating to Reverse Disease and Optimize Health.

[00:18:30] Bill Lagakos; Podcast: Why You Should Eat Breakfast (and Other Secrets of Circadian Biology).

[00:18:35] Nitric oxide.

[00:19:01] Malcolm Kendrick; Podcasts: Why Cholesterol Levels Have No Effect on Cardiovascular Disease (And Things to Think about Instead) and A Statin Nation: Damaging Millions in a Brave New Post-health World.

[00:19:25] Homocysteine; glycocalyx.

[00:21:20] Ivor Cummins; Podcasts with Ivor: How Not to Die of Cardiovascular Disease and Coronary Artery Calcium (CAC): A Direct Measure of Cardiovascular Disease Risk.

[00:22:24] UV exposure suppresses symptoms of metabolic syndrome; Study: Geldenhuys, Sian, et al. "Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet." Diabetes 63.11 (2014): 3759-3769.

[00:22:54] Melatonin.

[00:25:39] Serotonin; Study: Lambert, Gavin W., et al. "Effect of sunlight and season on serotonin turnover in the brain." The Lancet 360.9348 (2002): 1840-1842.

[00:26:26] Immunomodulation.

[00:26:45] Vitamin D and Multiple Sclerosis; Reduced risk of MS: van der Mei, Ingrid AF, et al. "Past exposure to sun, skin phenotype, and risk of multiple sclerosis: case-control study." Bmj 327.7410 (2003): 316; Reduced risk of depression and fatigue: Knippenberg, S., et al. "Higher levels of reported sun exposure, and not vitamin D status, are associated with less depressive symptoms and fatigue in multiple sclerosis." Acta Neurologica Scandinavica 129.2 (2014): 123-131; MRI neurodegeneration scores inversely associated with sun exposure: Zivadinov, Robert, et al. "Interdependence and contributions of sun exposure and vitamin D to MRI measures in multiple sclerosis." J Neurol Neurosurg Psychiatry 84.10 (2013): 1075-1081.

[00:27:20] UV treatment increased glucagon-stimulated insulin secretion; Study: Colas, C., et al. "Insulin secretion and plasma 1, 25-(OH) 2D after UV-B irradiation in healthy adults." Hormone and metabolic research 21.3 (1989): 154-155.

[00:27:27] Prevention and treatment of skin conditions; Study: Søyland, E., et al. "Sun exposure induces rapid immunological changes in skin and peripheral blood in patients with psoriasis." British Journal of Dermatology 164.2 (2011): 344-355.

[00:27:49] Sun exposure related to life expectancy; Study: Lindqvist, Pelle G., et al. "Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort." Journal of internal medicine 280.4 (2016): 375-387. 

[00:30:14] Outline of this interview.

[00:31:04] UVA and UVB rays; UVB needed for Vitamin D Production: Wacker, Matthias, and Michael F. Holick. "Sunlight and Vitamin D: A global perspective for health." Dermato-endocrinology 5.1 (2013): 51-108.

[00:31:31] Inverse correlation between dose of UVB and melanoma: Study: Godar, Dianne E., Madhan Subramanian, and Stephen J. Merrill. "Cutaneous malignant melanoma incidences analyzed worldwide by sex, age, and skin type over personal Ultraviolet-B dose shows no role for sunburn but implies one for Vitamin D3." Dermato-endocrinology 9.1 (2017): e1267077.

[00:33:43] Sunscreens; coral bleaching: Downs, Craig A., et al. "Toxicopathological effects of the sunscreen UV filter, oxybenzone (benzophenone-3), on coral planulae and cultured primary cells and its environmental contamination in Hawaii and the US Virgin Islands." Archives of environmental contamination and toxicology 70.2 (2016): 265-288. 

[00:43:20] Join the discussion on the NBT forum when you support us on Patreon.