Updated: December 1, 2020 

The importance of Vitamin D

Over 1 billion people across the globe are estimated to be deficient in vitamin D, are you one of them? [1]

Vitamin D is a hormone that helps to regulate blood calcium levels, supports bone health, and directly impacts the immune system. And it doesn’t stop there, vitamin D has been shown to reduce the risk of viral, microbial, and respiratory diseases.

A deficiency of vitamin D is linked to osteoporosis, multiple sclerosis, chronic fatigue syndrome, depression, type 2 diabetes, heart disease, and cancer. Currently, there are clinical trials studying correlations between Vitamin D and COVID-19. There is mounting evidence of vitamin D deficiency in individuals with compromised immune systems and the elderly, both groups are in the high-risk category for COVID-19. [2] In fact, the UK Government is planning on sending millions of elderly and vulnerable people a supply of Vitamin D to help in the battle against COVID-19.

As you can see, maintaining proper levels of vitamin D is necessary for overall health and in the battle against COVID-19.  As awareness grows regarding the possible connection between low vitamin D and COVID-19 we are seeing more of our patients supplement with vitamin D.  Next, I’ll explain how vitamin D and magnesium are connected to erectile dysfunction and why in most cases the two should be taken together.

Vitamin D and Erectile Dysfunction

I had a patient quit taking vitamin D because he thought that it caused erectile dysfunction (ED). I have now seen this happen in several men. This seems contradictory, as vitamin D is thought to improve cardiovascular and sexual health: studies actually show that the more depleted a man is in vitamin D, the more likely he is to have severe sexual dysfunction.[3] It turns out that when vitamin D actually creates sexual problems, it may reveal important information about deficiency of another nutrient—a mineral that is involved in more than 300 reactions in the body.

The Connection Between Vitamin D and Magnesium

When we look closely at the biochemistry, we see that magnesium is required for the conversion of vitamin D to its active form (1, 25-dihydroxyvitamin D). Vitamin D that is taken orally needs to go through this conversion, a process that can deplete magnesium stores. If a person begins to supplement vitamin D but does not have adequate magnesium intake, symptoms of magnesium deficiency can appear. Further investigation revealed that the patient mentioned above had also developed high blood pressure and heart palpitations since taking the vitamin D—symptoms of magnesium depletion.

Under normal circumstances, magnesium helps blood vessels relax. Low magnesium can lead to blood vessel constriction and high blood pressure. Additionally, low magnesium may not allow the penile vein to fully relax leading to erectile dysfunction. Other symptoms of low magnesium can include anxiety, insomnia, migraine headaches, muscle cramps, muscle twitches, or chronic pain.

Food sources of magnesium include:

  • Spinach
  • Swiss Chard
  • Pumpkin seeds
  • Sunflower seeds
  • Quinoa
  • Black beans

Magnesium is present in most beans, nuts, and whole grains, but half of the US population does not meet the minimum recommended intake of magnesium from food.[4]

When we added magnesium supplementation to the protocol for the patient described here, his sexual function improved, his blood pressure returned to normal, and his palpitations stopped. The interaction between vitamin D and magnesium is complex: magnesium is required to activate vitamin D, those who consume more magnesium have higher levels of vitamin D,[4] and now we see that vitamin D supplementation can deplete magnesium.

Vitamin D status should not be ignored, but magnesium deficiency is probably one of the most under-diagnosed deficiencies today. For the patient described here, it was magnesium that gave a man his life back.

Do You Know What Your Level of Vitamin D is?

Otherwise known as the “sunshine vitamin” vitamin D is obtained from direct sunlight or consuming foods such as salmon, sardines, tuna, eggs, and shiitake mushrooms. Vitamin D levels tend to be lower between October and early March from lack of sunlight. Everybody absorbs vitamin D at different rates. When levels are low, a supplement may be beneficial. As you learned in the article taking magnesium with vitamin D is imperative.

Visit our Online Store to purchase Ultra D3 capsules and Magnesium.

The best way to determine vitamin D status is with a simple blood test. At the Care Group, we routinely monitor our patients’ vitamin D levels. Call us at 303-343-3121 to have your levels checked.

Like what you learned? Click here to sign up for our eNewsletters by Dr. G to receive cutting-edge health tips straight to your inbox.

About The Care Group: We promote optimal wellness by providing an individualized, functional medicine approach to address root causes rather than simply treating symptoms. We help patients with a wide range of issues including autoimmune/ inflammatory disease, digestive disorders, hormone imbalances, and mood disorders. To learn more about our practice, click here.

About the Author: Dr. Gerard Guillory, MD is Board Certified in Internal Medicine and has published two books on Irritable Bowel Syndrome (IBS). In 1985, he opened The Care Group, PC. Today, his clinic is a Primary Care facility that is a hybrid of functional and traditional medicine treating patients with digestive disorders, autoimmune disease, and other conditions. You can learn more about Dr. Guillory here.


[1] Naeem Z. Vitamin d deficiency- an ignored epidemic. Int J Health Sci (Qassim). 2010;4(1):V-VI.

[2] Sidney J. Stohs & Okezie I. Aruoma (2020) Vitamin D and Wellbeing beyond Infections: COVID-19 and Future Pandemics, Journal of the American College of Nutrition, DOI: 10.1080/07315724.2020.1786302

[3] Barassi A, Pezzilli R, Colpi GM, Corsi Romanelli MM, Melzi d’Eril GV. Vitamin D and erectile dysfunction. J Sex Med. 2014;112792-2800.

[4] Rosanoff A, Weaver CM, Rude RK. Suboptimal magnesium status in the United States: are the health consequences underestimated. Nutr Rev. 2012;70(3):153-164.

[5] Zittermann A. Magnesium deficit? overlooked cause of low vitamin D status. BMC Med. 2013;11229.