What 20+ Studies Say About Vitamin D Supplementation
“Here comes the sun, and I say, it’s all right.”
Key Takeaways
By supplementing with Vitamin D, if your levels are below 40-60 ng/mL, you can boost immunity, improve your mood, and support hormone production.
For a quick summary of the health benefits of optimal Vitamin D levels, this infographic from Dr. Rhonda Patrick sums it all up very nicely:
Dr. Rhonda Patrick on Vitamin D (1).
Full Story
Everyone was naked, or at least scantily clad, for a significant chunk of human history. Sunlight washed over nearly every inch of our skin, providing us with ample amounts of vitamin D. But now, vitamin D deficiency is rampant across the world and is one of primary drivers of chronic disease.
The MOST IMPORTANT SUPPLEMENT you can possibly take is vitamin D. Creatine and protein powder can get you stronger, Omega-3’s can improve your heart health, but, if you’re deficient, no supplement can offer the same MAGNITUDE of benefit as vitamin D. Don’t take it from me, see what the experts have to say:
“Because vitamin D is so cheap and so clearly reduces all-cause mortality, I can say this with great certainty: Vitamin D represents the single most cost-effective medical intervention in the United States.” - Dr. Greg Plotnikoff
“This is like the Holy Grail of cancer medicine; vitamin D produced a drop in cancer rates greater than that for quitting smoking, or indeed any other countermeasure in existence.” - Dr. Dennis Mangan
“We estimate that vitamin D deficiency is the most common medical condition in the world.”- Dr. Michael F. Holick
Vitamin D is a steroid hormone that controls the expression of over 1000 different genes. The “sunshine vitamin” is best known for its integral role in calcium regulation and bone metabolism, but, more recently, there has been research that supports a relationship between adequate Vitamin D levels and a plethora of positive health effects (2).
Not sold yet? Here are the top 9 reasons you may want to consider supplementing with this super vitamin.
1. Enhance Mood and Reduce Symptoms of Depression
Depression is the leading cause of disability worldwide and rates of the disease are rapidly increasing. Although there is uncertainty about the directionality, there is link between depression and low Vitamin D levels (3). Vitamin D receptors in the brain are located in the same region as areas affected by depression, supporting the notion that inadequate vitamin D levels may increase depressive symptoms (4). In those that are deficient, Vitamin D has even been shown to have anti-depressive effects as strong as some medications (5).
Furthermore, Vitamin D regulates synthesis of serotonin, a “feel good” neurotransmitter. High levels of Vitamin D levels results in higher amounts of serotonin in the brain, increasing feeling of well-being (6). Depression is a complex condition with a wide range of causes, and Vitamin D is not a miracle cure. That being said, there is strong evidence that supplementation may act as an adjunct therapy to improve mood and reduce the severity of depressive symptoms.
2. Boost Immunity
Writing this in the quarantine of the Covid-19 outbreak, everyone is interested in increasing the strength of his/her immune system to prevent falling ill. A simple and easy way to ward off sickness is by maintaining adequate Vitamin D levels! Specifically, Vitamin D has been shown to both protect against respiratory tract infections, such as Covid-19, and decrease rates of influenza (7, 8).
3. Improve Sexual Function
“Everything in the world is about sex except sex. Sex is about power” - Oscar Wilde. Sex is important for a lot of reasons - too many to cover in this article. Low vitamin D levels have been consistently found to correlate with sexual dysfunction in both males and females.
Specifically, for the ladies, this study found that higher vitamin D levels in women aged 29-41 were associated with higher reported levels of desire, arousal, lubrication, orgasm, and satisfaction (9). Additionally, in this well controlled study of women aged 19-45 with low vitamin D levels and sexual dysfunction, vitamin D supplementation significantly improved sexual function (10).
Don’t fret, guys, similar effects are seen in males, too. Low levels of vitamin D are associated with higher rates of erectile dysfunction and this study found that Vitamin D replacement therapy in those that were deficient increases both free and total testosterone and erectile function (11, 12).
4. Decrease Risk of Cancer
The further away you live from the equator, the higher your risk of developing cancer (13). This association may be explained by decreased exposure to the sun and decreased levels of Vitamin D. Additionally, this study showed that Vitamin D deficiency is correlated with increased risk of cancer in men, especially for digestive system related cancers (14).
Proposed anti-cancer effects of Vitamin D include decreased cancer cell growth, increased cellular differentiation, stimulation of programmed cell death, and reduced tumor cell formation (15). Whatever the mechanism, it is clear adequate Vitamin D levels act as an effective defense against cancer.
5. Increase Strength
Most people know that creatine and protein powder are 2 of the most effective muscle building supplements, but can vitamin D increase performance in the gym, too?
This comprehensive study supports a relationship between increased levels of Vitamin D and increased strength, improved athletic performance, and decreased risk of injury and falls among the elderly (16). Therefore, whether you’re getting ready for football season or trying to prevent hip-breaking falls down the stairs, Vitamin D supplementation can enhance the effects of your training.
6. Decrease Risk of Autoimmune Disease
Autoimmune diseases are essentially bouts of inflammatory friendly fire in the body; they are conditions that develop after the body’s immune system mistakenly attacks healthy cells. Similar to the trend seen with cancer, rates of autoimmune disease increase the further away one lives from the equator.
Sufficient levels of Vitamin D have been shown to diminish T cell autoimmune response, decreasing your chance of developing conditions such as Type 1 Diabetes, Rheumatoid Arthritis, and Multiple Sclerosis (17). If autoimmune disease runs in your family and/or you live in a northern, darker climate, it my be wise to supplement with Vitamin D.
7. Decrease Risk of Dementia
After working in a nursing home for a summer, one of my worst fears became watching my parents develop dementia. Right now, 5-7% of people over the age of 60 live with dementia and worldwide rates are rapidly increasing, expecting to reach 82 million people by 2030 (18).
One way to prevent this devastating disease is to get enough sunlight – Vitamin D deficiency is associated with a significantly increased risk of developing dementia and, specifically, Alzheimer’s Disease (19).
A few of the more alarming Alzheimer’s statistics (20).
8. Reduce Effects of Aging
The search for the fountain of youth is as simple as stepping outside in the sunshine; the lower your levels of Vitamin D, the more likely you are to die! There is an inverse correlation between serum Vitamin D levels and markers of aging, including frailty and all-cause mortality rates (21).
Vitamin D deficiency is also associated with higher levels of DNA damage and increased telomere shortening. Telomeres are essentially little shoelace tips that protect your shoelace-like DNA from damage and longer telomeres are associated with a longer lifespan. In order to age more gracefully, make sure to get enough Vitamin D in your life.
9. Maintain Optimal Testosterone Levels
Our grandfathers were manlier than us – average levels of testosterone have decreased by 1% every year since the 1980’s. (22). This plummet in testosterone makes everybody sad, resulting in smaller muscles, lower sex drives, and higher rates of chronic diseases. Fortunately, one effective way to combat these disappointing hormonal changes is by taking mother nature’s secret steroid, Vitamin D!
Men with adequate Vitamin D levels have higher levels of testosterone and lower levels of testosterone-decreasing SHBG (steroid hormone binding globulin (23). This is especially important to consider for older adults as testosterone decreases with age at a rate of about 1% per year after age 30.
After age 30, males experience a sharp decrease in average testosterone levels (24).
What else should I know?
Due to genetic and lifestyle differences, Vitamin D supplementation is more important for a few subsets of the population. Factors affecting vitamin D levels include age, body fat levels, and skin pigmentation.
Age: With increasing age, the body produces lower levels of vitamin D. A 20-year-old produces about 4x as much vitamin D as a 70-year-old.
Body Fat: Vitamin D is a lipid soluble vitamin, meaning it is dissolved by and stored in fat. The higher your body fat percentage, the more vitamin D you have stored in that fat and less you have available in your bloodstream.
Skin Pigmentation: The darker your skin, the more melanin your body produces. This is great for saving money on sunscreen, but it also inhibits Vitamin D production. If you have a darker skin tone, you may be susceptible to inadequate Vitamin D levels.
Thus, if you’re an older adult, have a high body fat percentage, or have a darker skin tone, it is much more likely that you will need to supplement in order to boost your Vitamin D levels to the optimal range of between 40 and 60 ng/mL.
Wrap Up
The best way to achieve and maintain adequate vitamin D levels is to undergo frequent blood draws to assess your levels and find your personal, optimal dose. BUT, most people are not willing to go to those lengths to get such accurate data.
If you fall into this camp, you can’t go wrong with taking a Vitamin D3 and K2 supplement during the winter months and on rainy days (when you’re less likely to be exposed to sunlight). Vitamin D3 is often paired with K2 because the pair works in synergy to maintain high levels of calcium in both the blood and bones, and prevents the build up of calcium in blood vessels and other soft tissues in the body (25). T
hough vitamin D toxicity is extremely rare, vitamin K2 also offers a protective effect against harmfully high levels of vitamin D in the blood. No matter your approach, there is little doubt that maintaining optimal vitamin D levels is a cheap, effective, and safe way to promote health and longevity.
Sources
https://www.foundmyfitness.com/vitamin-d
http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/otherendo/vitamind.html
http://www.jneuropsychiatry.org/peer-review/depression-and-vitamin-d-deficiency-causality-assessment-and-clinical-practice-implications-12051.html
https://pubmed.ncbi.nlm.nih.gov/27522658/
https://pubmed.ncbi.nlm.nih.gov/30395842/?from_term=Vitamin+D+AND+%22Sexual+Function%22&from_pos=2
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3427191/
https://pubmed.ncbi.nlm.nih.gov/29531528/?from_term=Vitamin+D+AND+%22Sexual+Function%22&from_pos=1
https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/vitamin-d-fact-sheet
https://academic.oup.com/jnci/article/98/7/451/2522019
https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/vitamin-d-fact-sheet
https://sogacot.org/effects-of-vitamin-d-on-skeletal-muscle-and-athletic-performance/
https://lpi.oregonstate.edu/mic/vitamins/vitamin-D#autoimmune-diseases-prevention
https://www.who.int/news-room/fact-sheets/detail/dementia
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4153851/
https://communityjournal.net/alzheimers-disease-in-wisconsin-a-new-report/
https://www.sciencedirect.com/science/article/abs/pii/S0378512211000582
https://uk.reuters.com/article/health-testosterone-levels-dc-idUKKIM16976320061101
https://pubmed.ncbi.nlm.nih.gov/20050857/
https://www.healthplus.clinic/hormones
https://www.healthline.com/nutrition/vitamin-d-and-vitamin-k#TOC_TITLE_HDR_4
