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Vitamin D

David Tomen
Author:
David Tomen
18 minute read
Vitamin D has been shown to relieve depression & SAD, is critical for learning & memory, and helps prevent age-related cognitive decline

In a hurry – click here to learn more about Performance Lab® NutriGenesis® Vitamin D3 + K2

Vitamin D3 (cholecalciferol or calciol) is the fat-soluble steroid hormone form of Vitamin D. The “sunshine vitamin” is considered essential. Your skin synthesizes Vitamin D3 from ultraviolet-B (UVB) sunlight.

Nearly every tissue and cell type in your body and brain has Vitamin D receptors (VDR). It’s commonly associated with immune and bone health.

But Vitamin D3 as a nootropic supplement is critical for optimal cognitive health. It’s an integral part of neurotransmitter synthesis, gene expression, DNA maintenance and repair, and the forms of neuroplasticity needed for memory formation and retrieval.

Vitamin D deficiency (hypovitaminosis D) is an undeclared worldwide pandemic affecting nearly 50% of the population on this planet.

Vitamin D brain benefitsThe major cause of this Vitamin D deficiency is inadequate exposure to sunlight. Wearing sunscreen with a SPF of 30 reduces Vitamin D synthesis in your skin by more than 95%.[i]

Working and living indoors in our modern world contributes to this problem. Those with a naturally dark skin tone require 3 – 5-times longer sun exposure to the make the same amount of Vitamin D as those with a lighter skin tone.[ii]

Also at risk of Vitamin D deficiency is anyone who works indoors, breastfed infants, older adults, and anyone homebound, or who wear long garments for religious reasons. If you have fat malabsorption issues, obese, or on certain medications you are also at risk.

You risk a host of problems if you don’t get enough Vitamin D. Including Type-2 diabetes, depression, cognitive impairment, Parkinson’s or Alzheimer’s Disease among others.

Vitamin D exists in two forms. Vitamin D2 is obtained from the UV irradiation of the yeast sterol ergosterol and is found naturally in sun-exposed mushrooms. UVB light from the sun strikes the skin, and humans synthesize Vitamin D3, so it is the most “natural” form.

Note: I’ll be using Vitamin D and Vitamin D3 interchangeably throughout this review.

Supplementing with high quality Vitamin D3 is inexpensive and simple. If you could do one thing to improve the efficacy and potency of your nootropic stack. Add Vitamin D3 to your daily stack.

Find a high quality liposomal Vitamin D3 supplement for better absorption like the Performance Lab® Vitamin D3 + K2. And get some sun every day.

Here’s we’ll investigate what science has discovered in the last decade about how Vitamin D3 works in your brain.

Vitamin D helps:

  • Neurotransmitters: Vitamin D3 with Omega-3’s are needed for serotonin synthesis, release and function. Regulating executive function, sensory gating, and social behavior.[iii] And Vitamin D3 is involved in the synthesis of GABA, glutamate and glutamine, and dopamine in the brain.[iv]
  • Neuroprotective: Vitamin D3 protects against DNA damage through prevention of telomere shortening and inhibition of telomerase activity. And prevents oxidative damage to DNA.[v]
  • Mood: Vitamin D3 is involved in neuromodulation, regulation of neurotrophic factors, neuroprotection, neuroplasticity, and brain development. All in areas of the brain associated with depression. Supplementation could be an important part of treatment of depression.[vi]

Overview

Vitamin D3 (cholecalciferol or calciol) is unique because it is not a standard vitamin. It’s actually a fat-soluble steroid hormone.

Vitamin D is mostly made in your skin from sun exposure. Not primarily from food like most of our other vitamins.

Vitamin D Cholecalciferol
Vitamin D (cholecalciferol)

When Ultraviolet-B (UVB) light from the sun strikes your skin, your body synthesizes Vitamin D3.

Vitamin D that comes from your skin, or from food or a supplement, is not active. It first requires hydroxylation in your liver by the enzyme vitamin D-25-hydroxylase (25-OHase) to 25(OH)D.[vii]

Then 25(OH)D requires further hydroxylation in your kidneys by the 25(OH)D-1-OHase to form the biologically active form of vitamin D called 1,25(OH)2D (cholecalciferol).

You get some Vitamin D from foods like fatty fish (tuna, salmon, and mackerel), beef liver, cheese, egg yolks, and mushrooms. Some foods in the USA are fortified with Vitamin D. It’s added to breakfast cereals, soy beverages, yogurt and margarine. Check the nutrition fact panel on the food label.

Cholecalciferol is also produced industrially for use in nootropic supplements, and to fortify foods. It is produced using ultraviolet irradiation of 7-dehydrocholesterol extracted from lanolin in sheep’s wool.

Vitamin D3 directly or indirectly regulates the function of up to 2,000 genes in your body and brain.[viii] Vitamin D works in concert with Vitamin D receptors (VDR) located throughout your body and brain.

Recent research shows Vitamin D is involved in nerve growth factor (NGF) synthesis. Which is responsible for the growth and maintenance of neurons.

Vitamin D is also involved in neuron apoptosis. Studies have shown that low Vitamin D levels interrupts this cell cycle. Leading to several neurological disorders including dementia, Parkinson’s, MLS, epilepsy, and schizophrenia.[ix]

Alzheimer’s disease is associated with a decrease in Vitamin D receptors in the hippocampus. Lack of gene expression from insufficient Vitamin D contributes to Parkinson’s Disease.[x]

Hypovitaminosis D (low Vitamin D) is associated with an increase in proinflammatory cytokines and a decrease in anti-inflammatory cytokines. The increase in these specific cytokines is associated with the degradation of the myelin sheath. Leading to Multiple Sclerosis (MLS).

Studies are currently underway for using Vitamin D3 to reduce seizures in those dealing with epilepsy. The anticonvulsant effects are based on Vitamin D3’s ability to regulate the expression of genes. A process that is mediated by Vitamin D receptors.[xi]

Scientists and researchers in labs around the world continue to build on the knowledgebase for Vitamin D. And how the sunshine vitamin affects human cognition and overall health.

Vitamin D memory and concentration

How does Vitamin D work in the brain?

Vitamin D boosts brain health and function in several ways. But two in particular stand out.

  1. Vitamin D helps relieve depression. Vitamin D activates genes that regulate your immune system and the release of neurotransmitters including dopamine and serotonin.

Research has also located Vitamin D receptors in areas of the brain linked to depression. A meta-analysis of clinical studies on depression and Vitamin D status including 31,424 participants showed that low Vitamin D concentrations is associated with depression.[xii]

One of several other studies on Vitamin D[xiii] and depression showed that older adults with low Vitamin D levels were 11-times more likely to be depressed than those with normal levels.[xiv]

And if you’re currently using antidepressants without much success, this next study may provide some hope.

A study conducted in Iran with 42 patients with major depressive disorder participated in a double-blind, randomized, placebo-controlled trial. One group received 1,500 IU of Vitamin D3 plus 20 mg of fluoxetine (Prozac®), or fluoxetine alone for 8 weeks.

In this 8-week trial, the vitamin D + fluoxetine combination was superior to fluoxetine alone in controlling depressive symptoms.[xv]

  1. Vitamin D is essential for learning and memory. Vitamin D has been shown to play a critical role in neuron cell growth and differentiation, neuron transmission, and the neuroplasticity that’s essential for optimal learning and memory.[xvi]

Vitamin D has been shown in the lab to protect against age-related cognitive decline. In one study conducted in Detroit, researchers worked with aged rats. Older rats have problems with cognitive testing. Along with elevated levels of pro-inflammatory cytokines, decreased levels of anti-inflammatory cytokines, and higher levels of amyloid-beta proteins in their brains.

Supplementing with Vitamin D for only 21 days reversed the inflammation and improved the clearance of amyloid-beta. Showing potential for using Vitamin D to prevent age-related cognitive decline.[xvii]

Vitamin D and brain fog

How things go bad

Vitamin D deficiency is a global health problem. Over a billion people worldwide are Vitamin D deficient.[xviii]

The major cause of this deficiency is the lack of appreciation that getting enough sun every day is the major source of Vitamin D for most people.

Very few foods contain Vitamin D. And foods that are fortified are inadequate to provide a child or adult’s daily requirement.

Top that off with the media and mainstream medical establishment hysteria about skin cancer. And the use of sunblock.

If you work indoors, wear ‘excessive’ clothing, use sunblock, are dark skinned, overweight, aged, or consciously avoid the sun, you are at risk for Vitamin D deficiency.

↓ Pathogens can inhibit Vitamin D receptors

↓ Lack of natural sun exposure depresses Vitamin D levels

↓ Caffeine inhibits Vitamin D receptors

↓ Testosterone levels decline

↑ Risk of bone fractures increases

↑ Increased risk of cancer, autoimmune disease, hypertension, infectious disease

↓ Severe Vitamin D deficiency can result in dementia and Alzheimer’s

↑ Increase in symptoms of depression

Vitamin D3 supplementation can help alleviate depression and improve learning and memory.

Vitamin D improves memory

Vitamin D benefits

Not too long ago, Vitamin D was simply known as the ‘bone vitamin’. But there has been a surge in Vitamin D research over the last decade.

Out of that research, it was discovered that nearly every cell type and tissue in your body have receptors for this essential vitamin. And quickly changed how we understand the role of Vitamin D in the body.

We now know that Vitamin D deficiency is a problem worldwide. To put this in perspective, studies estimate 64% of Americans don’t get enough Vitamin D.[xix]

We now have clinical evidence that Vitamin D influences our autoimmune system, heart health, prevents infectious disease, and supports optimal cognition.

Vitamin D deficiency has been linked to Alzheimer’s and Parkinson’s disease, asthma, autism, depression, cancer, and diabetes.

A Japanese study found that 1,200 IU of Vitamin D daily reduced the risk of getting the flu by almost 50%.[xx]

One 7-year study showed Vitamin D deficiency substantially increased the risk of non-Alzheimer’s dementia.[xxi] Another 7-year study associated higher Vitamin D levels with a significantly lower risk of developing Alzheimer’s.[xxii]

Animal and human studies suggest that Vitamin D could help in the prevention and treatment of cognitive decline and dementia.

And a study published in the American Journal of Clinical Nutrition demonstrated Vitamin D supplementation is anti-aging because it increases telomere length.

How does Vitamin D feel?

If you work or spend most of your time indoors, you’re getting less sun than you should. And you may notice that your mood deteriorates relative to the amount of time you spend outside. This is especially noticeable in the winter if you live well north or south of the Equator.

Vitamin D cognitive performanceA capsule of Vitamin D3 in the morning is like a little dose of sunshine. You’ll feel brighter even on the grayest of days.

Many who supplement with Vitamin D3 report feeling happier. Energy levels are higher and feelings of depression stay away.

Some report a noticeable decrease in Fibromyalgia pain. Pain after exercise is less pronounced.

Seasonal depression is officially known as “Seasonal Affective Disorder” (SAD). Vitamin D3 is a potent remedy for many experiencing SAD. It’ll keep that winter depression at bay and reduce mood swings.

Many report that supplementing with Vitamin D3 reduces insomnia. Sleep is deeper and your mood is better the next day.

Vitamin D Clinical Research

Vitamin D may prevent autism

A study led by Professor Bruce Ames of Children’s Hospital Oakland Research Institute demonstrated that oxytocin, serotonin and vasopressin are all activated by Vitamin D.

Abnormal social behavior is one of the symptoms of autism. And has been previously linked to low serotonin and Vitamin D levels in the brain. This study shed light on the mechanism of action that could explain this relationship.

The study showed that Vitamin D activates the transcription of the serotonin-synthesizing gene tryptophan hydroxylase 2 (TPH2) in the brain at a Vitamin D response element (VDRE). And suppresses the transcription of TPH1 in tissues outside the blood-brain barrier.

The study explains that this mechanism shows how low Vitamin D hormone levels result in aberrant serotonin synthesis. Leading to abnormal brain development.

The study authors suggested that, “Supplementation with Vitamin D and tryptophan is a practical and affordable solution to help prevent autism and possibly ameliorate some symptoms of the disorder.”[xxiii]

Vitamin D may prevent dementia & stroke

Dementia is one of the greatest health challenges of our time. An estimated 44 million people worldwide suffer from dementia. This number is expected to triple by 2050 as the population ages.

A recent study at the University of Exeter Medical School found that adults who were slightly deficient in Vitamin D have a 53% increased risk of developing dementia of an kind.

That risk increased to 125% in those who were severely deficient in Vitamin D. The same study found that the moderately deficient group were 69% more likely to develop Alzheimer’s. And the severely deficient were 122% more likely to develop this disease.[xxiv]

Another study at the University of Heidelberg in Germany included 3,316 patients who were referred for evaluation of their arteries. Those with low Vitamin D levels were found to be more likely to have a fatal stroke within the next 7 years.

The researchers concluded, “vitamin D supplementation is a promising approach in the prevention of strokes”.[xxv]

Vitamin D for Seasonal Affective Disorder (SAD)

Seasonal Affective Disorder (SAD) is a mood disorder characterized by depression that occurs during fall and winter months when sunlight levels are low.

SAD typically coincides with a sudden drop in Vitamin D levels in the body. Several studies have suggested that SAD could be due to changing Vitamin D3 levels. Which affects serotonin levels in the brain.[xxvi]

One study with adults dealing with Vitamin D deficiency found that supplementing with 4,000 IU of Vitamin D daily for 2 months relieved their depression symptoms.[xxvii]

Another study recruited 441 people in an outpatient clinic in Norway. This randomized, double-blind trial had patients using 20,000 or 40,000 IU Vitamin D per week or placebo for 1 year.

Subjects with serum Vitamin D levels below 40 nmol/L were significantly more depressed than those with levels above 40 nmol/L. In the two groups given Vitamin D there was a significant improvement in depression symptoms after 1 year. But no improvement in the placebo group.

The study concluded, “It appears to be a relation between serum levels of 25(OH)D and symptoms of depression. Supplementation with high doses of vitamin D seems to ameliorate these symptoms indicating a possible causal relationship.”[xxviii]

Vitamin D recommended dosage

The Institute of Medicine recommends adults use 4,000 IU per day for Vitamin D3. Vitamin D is fat-soluble. So make sure you take it with a meal containing healthy fats. Or a tablespoon of unrefined coconut or olive oil.

A study published in the American Journal of Clinical Nutrition suggests optimal Vitamin D status is achieved with a serum (blood) 25-hydroxyvitamin D concentration >75 nmol/L (30 ng/mL)

Vitamin D deficiency and cognitive impairmentTo achieve blood levels of 100 nmol/L, research has found that you need total daily Vitamin D supplementation of 4,000 IU.

It is possible to get your daily dose of Vitamin D from the sun. And total-body sun exposure provides the equivalent of 10,000 IU of Vitamin D.[xxix]

But chances are none of us has the opportunity to sunbathe nude every single day to get our dose of Vitamin D.

To determine how much Vitamin D3 you needed to take to achieve optimal concentrations of this crucial vitamin, researchers recruited 138 volunteers for a 6-month randomized, double-blind, placebo-controlled trial.

The researchers found that if your blood Vitamin D status was less than 55 nmol/L you needed a daily intake of 5,000 IU. And for those above 55 nmol/L you needed a dose of 3,800 IU of Vitamin D3 per day.[xxx]

The Institute of Medicine also found that the dose for lowest observed adverse effect is 40,000 IU of Vitamin D daily for at least 12 weeks.

Get your Vitamin D levels checked. Be sure the lab tests for “25-hydroxyvitamin D”. To raise your blood levels of Vitamin D to optimal levels, you need to take 100 IU of Vitamin D3 for each 1 ng/mL you need to raise it.[xxxi]

Vitamin D Side Effects

Vitamin D is non-toxic. So is considered well-tolerated and safe.

Side effects are rare but can include dry mouth, fatigue, headaches, metallic taste, nausea, sleepiness and vomiting.

Doses of Vitamin D higher than 4,000 IU daily is possibly unsafe because it could cause excessive blood levels of calcium. But note that much higher doses are sometimes used for short-term treatment of Vitamin D deficiency. Get your labs done!

Vitamin D could worsen atherosclerosis (hardening of the arteries). If you have sarcoidosis, histoplasmosis, are hyperthyroid, have lymphoma, or tuberculosis Vitamin D could increase blood calcium levels causing kidney stones and other problems.

Vitamin D may affect blood pressure. So be cautious about using Vitamin D if you’re dealing with blood pressure disorders, are taking drugs or supplements that affect blood pressure.

Vitamin D may affect blood sugar levels. So if you’re taking drugs for diabetes or insulin you should monitor your Vitamin D levels and adjust medication as necessary.

Some drugs used to lower cholesterol, or treat psoriasis, calcium channel blockers, corticosteroids, and others may interact with Vitamin D. Check the University of Maryland’s “Possible Interactions” section of their article on Vitamin D for more drug interactions.

Types of Vitamin D to buy

The preferred way of getting Vitamin D is by exposing your skin to the sun. But the color of your skin will affect the synthesis of this essential vitamin.

Lighter skin may require 45 minutes of exposure 3-times per week. Dark skin may require up to 3-hours of exposure 3-times per week.

But since most of us spend so much time indoors. And have the nasty habit of using sunscreen when we do go outside. To maintain adequate Vitamin D levels then using a supplement is best.

Performance Lab NutriGenesis Vitamin D3+K2Vitamin D3 (cholecalciferol) is preferred over Vitamin D2 (ergocalciferol), since D3 is the form your body synthesizes naturally.

A meta-analysis by the Cochrane Database investigated morality rates for those who supplemented with Vitamin D2 vs Vitamin D3. The analysis of 50 randomized controlled trials including 95,000 participants showed:

  • A 6% risk reduction among those who used Vitamin D3
  • A 2% risk increase among those who used Vitamin D2

The overwhelming evidence shows that you are more likely to die using Vitamin D2 rather than with D3.[xxxii]

So if your doctor prescribes synthetic Vitamin D2 (Drisdol), kindly decline and get a Vitamin D3 supplement at the vitamin shop.

Or get your Vitamin D3 from a high-quality multi like the Performance Lab® NutriGenesis Multi for men or women.

Or my favorite standalone Vitamin D3 supplement is the new liposomal Performance Lab® Vitamin D3 + K2. This Vitamin D3 supplement offers 1,000 IU of Vitamin D3 with 50 mcg NutriGenesis® Vitamin K2 to ensure calcium absorption into your bones. In a NutriCaps® Pullulan Capsule with zero toxic “other ingredients”. Just a pure nutrient that your body and brain can use soon after you take it.

I prefer the Performance Lab® brand of supplements because they are more potent, biologically active and I’ve found to be a far more effective compared to other supplements I’ve used.

Performance Lab® uses their own priority NutriGenesis® vitamins and minerals which are grown on probiotic, plant and yeast cultures in a state-of-the-art lab.

Vitamin D3 is also available in softgel capsules, tablets and as a liquid.

If you have trouble digesting fat, Vitamin D injections are also available by prescription.

Calcitriol is a synthetic Vitamin D analog available by prescription which is used by dialysis and hypo parathyroid patients.

Nootropics Expert Recommendation

Nootropics Expert Tested and ApprovedVitamin D3 4,000 IU’s per day

I recommend using Vitamin D3 as a nootropic supplement.

Your body does make Vitamin D on its own by synthesizing it from UVB sunlight on exposed skin. Which is the preferred way of getting Vitamin D.

But all kinds of things can interfere with getting enough Vitamin D from sunlight. Fall and Winter in both hemispheres, cloud cover, smog, skin color, sunscreen, and too much clothing are all factors.

And most of us spend so much time indoors, to get its benefits you should take Vitamin D3 as a supplement.

It’s best if you get your Vitamin D levels checked. Be sure the lab tests for “25-hydroxyvitamin D”. To raise your blood levels of Vitamin D to optimal levels, you need to take 100 IU of Vitamin D3 for each 1 ng/mL you need to raise it.

Vitamin D is especially helpful for anxiety and depression. Vitamin D deficiency has been associated with depression, schizophrenia, psychotic symptoms and suicide.[xxxiii]

Vitamin D is also helpful for those dealing with autism, Alzheimer’s and Parkinson’s.

Doses should not exceed 10,000 IU daily unless supervised by a doctor. Vitamin D toxicity can happen with doses exceeding 40,000 IU per day for an extended period.

Vitamin D supplementation is one of the simplest and least expensive ways to optimize your brain. And should be part of every nootropic stack.

One great option is a high-quality multi containing a nature-identical Vitamin D3 like included in the Performance Lab® NutriGenesis Multi. It’s the best multi I’ve found and use every day. And add a separate liposomal Performance Lab® Vitamin D3 + K2 to your stack to ensure you maintain healthy Vitamin D levels.

Vitamin D is fat-soluble. So make sure you take your dose with a meal. Or a high quality fat like coconut or olive oil.

But please see the “Side Effects” section of this review for conditions and medication interactions before you start using Vitamin D.

As an Amazon Associate I earn from qualifying purchases. This post may also contain other affiliate links and I will be compensated if you make a purchase after clicking on my links.

[i] Matsuoka L.Y., Ide L., Wortsman J., MacLaughlin J.A., Holick M.F. “Sunscreens suppress cutaneous vitamin D3 synthesis.” Journal of Clinical Endocrinology and Metabolism. 1987 Jun; 64(6):1165-8. (source)

[ii] Clemens T.L., Adams J.S., Henderson S.L., Holick M.F. “Increased skin pigment reduces the capacity of skin to synthesise vitamin D3.” Lancet. 1982 Jan 9; 1(8263):74-6. (source)

[iii] Patrick R.P., Ames B.N. “Vitamin D and the omega-3 fatty acids control serotonin synthesis and action, part 2: relevance for ADHD, bipolar disorder, schizophrenia, and impulsive behavior.” The FASEB Journal 2015 Jun;29(6):2207-22. (source)

[iv] Jiang P., Zhang L.H., Cai H.L., Li H.D., Liu Y.P., Tang M.M., Dang R.L., Zhu W.Y., Xue Y., He X. “Neurochemical effects of chronic administration of calcitriol in rats.” Nutrients. 2014 Dec 22;6(12):6048-59 (source)

[v] Nair-Shalliker V., Armstrong B.K., Fenech M. “Does vitamin D protect against DNA damage?” Mutation Research. 2012 May 1;733(1-2):50-7 (source)

[vi] Fernandes de Abreu D.A., Eyles D., Féron F. “Vitamin D, a neuro-immunomodulator: implications for neurodegenerative and autoimmune diseases.” Psycho-neuroendocrinology. 2009 Dec;34 Supplement 1:S265-77. (source)

[vii] Standing Committee on the Scientific Evaluation of Dietary Reference Intakes Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. Chapter 7. Vitamin D. Retrieved October 14, 2017

[viii] Kamen D.L., Tangpricha V. “Vitamin D and molecular actions on the immune system: modulation of innate and autoimmunity” Journal of Molecular Medicine (Berlin) 2010 May; 88(5): 441–450. (source)

[ix] Goodsell, D.S. (2004). “The molecular perspective: cytochrome c and apoptosis.” The Oncologist Fundamentals of Cancer Medicine. 2004(9),226-227

[x] Luong K., Nguyen L. “Role of Vitamin D in Parkinson’s Disease” ISRN Neurology 2012; 2012: 134289. (source)

[xi] Pendo K., DeGiorgio C.M. “Vitamin D3 for the Treatment of Epilepsy: Basic Mechanisms, Animal Models, and Clinical Trials” Frontiers in Neurology 2016; 7: 218. (source)

[xii] Anglin R.E., Samaan Z., Walter S.D., McDonald S.D. “Vitamin D deficiency and depression in adults: systematic review and meta-analysis.” British Journal of Psychiatry. 2013 Feb;202:100-7 (source)

[xiii] Spedding S., “Vitamin D and Depression: A Systematic Review and Meta-Analysis Comparing Studies with and without Biological Flaws” Nutrients 2014 Apr; 6(4): 1501–1518. (source)

[xiv] Wilkins C.H., Sheline Y.I., Roe C.M., Birge S.J., Morris J.C. “Vitamin D Deficiency Is Associated With Low Mood and Worse Cognitive Performance in Older Adults” The American Journal of Geriatric Psychiatry December 2006 Volume 14, Issue 12, Pages 1032–1040 (source)

[xv] Khoraminya N., Tehrani-Doost M., Jazayeri S., Hosseini A., Djazayery A. “Therapeutic effects of vitamin D as adjunctive therapy to fluoxetine in patients with major depressive disorder.” Australian and New Zealand Journal of Psychiatry. 2013 Mar;47(3):271-5. (source)

[xvi] DeLuca G.C., Kimball S.M., Kolasinski J., Ramagopalan S.V., Ebers G.C. “Review: the role of vitamin D in nervous system health and disease.” Neuropathology and Applied Neurobiology. 2013 Aug;39(5):458-84. (source)

[xvii] Briones T.L., Darwish H. “Vitamin D mitigates age-related cognitive decline through the modulation of pro-inflammatory state and decrease in amyloid burden.” Journal of Neuroinflammation. 2012 Oct 25;9:244 (source)

[xviii] Holick M.F., Chen T.C. “Vitamin D Deficiency- An Ignored Epidemic” American Journal of Clinical Nutrition. 2008 Apr; 87(4):1080S-6S. (source)

[xix] Mitchell D.M., Henao M.P., Finkelstein J.S., Burnett-Bowie S.A. “Prevalence and predictors of vitamin D deficiency in healthy adults.” Endocrine Practice. 2012 Nov-Dec;18(6):914-23 (source)

[xx] Holick M. “Vitamin D is essential to the modern indoor lifestyle” Science News Vol. 178 #9, October 23, 2010, p. 32 (source)

[xxi] Annweiler C., Rolland Y., Schott A.M., Blain H., Vellas B., Beauchet O. “Serum vitamin D deficiency as a predictor of incident non-Alzheimer dementias: a 7-year longitudinal study.” Dementia & Geriatric Cognitive Disorders. 2011;32(4):273-8. (source)

[xxii] Annweiler C., Rolland Y., Schott A.M., Blain H., Vellas B., Herrmann F.R., Beauchet O. “Higher vitamin D dietary intake is associated with lower risk of alzheimer’s disease: a 7-year follow-up.” Journals of Gerontology, Series A. Biological Sciences and Medical Sciences. 2012 Nov;67(11):1205-11. (source)

[xxiii] Patrick R.P., Ames B.N. “Vitamin D hormone regulates serotonin synthesis. Part 1: relevance for autism” The FASEB Journal vol. 28 no. 6 2398-2413 (source)

[xxiv] Littlejohns T.J. et. Al. “Vitamin D and the risk of dementia and Alzheimer disease” Neurology August 14, 2014 (source)

[xxv] Pilz S., Dobnig H., Fischer J.E., Wellnitz B., Seelhorst U., Boehm B.O., März W. “Low vitamin d levels predict stroke in patients referred to coronary angiography.” Stroke. 2008 Sep;39(9):2611-3. (source)

[xxvi] Berk M., Sanders K.M., Pasco J.A., Jacka F.N., Williams L.J., Hayles A.L., Dodd S. “Vitamin D deficiency may play a role in depression.” Medical Hypotheses. 2007;69(6):1316-9. (source)

[xxvii] Vieth R., Kimball S., Hu A., Walfish P.G. “Randomized comparison of the effects of the vitamin D3 adequate intake versus 100 mcg (4000 IU) per day on biochemical responses and the wellbeing of patients” Nutrition Journal 2004; 3: 8. (source)

[xxviii] Jorde R., Sneve M., Figenschau Y., Svartberg J., Waterloo K. “Effects of vitamin D supplementation on symptoms of depression in overweight and obese subjects: randomized double blind trial.” Journal of Internal Medicine. 2008 Dec;264(6):599-609 (source)

[xxix] Vieth R. “Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety.” American Journal of Clinical Nutrition 1999 May;69(5):842-56. (source)

[xxx] Aloia J.F., Patel M., Dimaano R., Li-Ng M., Talwar S.A., Mikhail M., Pollack S., Yeh J.K. “Vitamin D intake to attain a desired serum 25-hydroxyvitamin D concentration.” American Journal of Clinical Nutrition 2008 Jun;87(6):1952-8. (source)

[xxxi] Holick M.F. “Vitamin D: evolutionary, physiological and health perspectives.” Current Drug Targets. 2011 Jan;12(1):4-18. (source)

[xxxii] Bjelakovic G., Gluud L.L., Nikolova D., Whitfield K., Wetterslev J., Simonetti R.G., Bjelakovic M., Gluud C. “Vitamin D supplementation for prevention of mortality in adults.” Cochrane Database of Systematic Reviews. 2011 Jul 6;(7):CD007470 (source)

[xxxiii] Grudet C., Malm J., Westrin A., Brundin L. “Suicidal patients are deficient in vitamin D, associated with a pro-inflammatory status in the blood.” Psychoneuroendocrinology. 2014 Dec;50:210-9. (source)

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Join The Discussion - 65 comments

Roy Underhill
July 25, 2020

i ate 10,000 ui of vitamin d3 and i got really dizzy and tired. I also was turned into a shrew. (I got better)

Reply

    David Tomen
    July 26, 2020

    Roy, I’m glad you’re no longer a shrew. I can’t imagine that would be like. Unless of course, you were a shrew. But a good lesson to not to overdose anything. Including vitamins.

    Vitamin D toxicity causes a buildup of calcium in your blood (hypercalcemia) which worst case causes bone pain and kidney problems.

    Reply

Eddie
February 14, 2020

Hi David, About 8 years ago I checked my vitamin D levels for the first time ever. I was deficient. During the time of my deficiency, my eyes were always gritty and dry. After getting on the Vitamin D supplementation The issues with my eyes went away. I had my genetic analysis done a few years ago and I apparently have the genetic variant that reduces vitamin D in the body. I have been taking 5000 IU’s daily for years. My blood levels have never gone higher than 50 ng/mL during this time. In August of 2019, my D levels were 48 ng/mL. I decided to cut back to 5000 IU’s every other day and when I tested my D levels they were 31. I switched from the Vitacost brand to the NOW Foods brand in November 2019 and went back to 5000 IU’s daily and retested in January 2020. My levels of vitamin D came in at 65.9, my highest level ever. The lab reference range for Vitamin D is 30.0-100.0 ng/mL. I was thinking to continue at 5000 IU daily and retest in a couple of months to determine if I should cut back a little or maintain. How does this plan sound to you? PS: The only supplement that I added to during time frame was the lithium oratate. I wonder if that had any effects on my Vitamin D finally moving up past 50 or the brand change?

Reply

    David Tomen
    February 14, 2020

    Eddie, I doubt Lithium Orotate had any effect on Vitamin D levels. But you clearly demonstrated the difference in quality between two manufacturers.

    Stay with your plan and your levels checked again like you plan to.

    Reply

      Eddie
      February 14, 2020

      thanks again.

      Reply

Charles
February 2, 2020

Hi David, I was taking 5000 ui of D3 two times daily, so 10,000. Developed tinnitus a month ago. Read elsewhere that an overdose of D could trigger it. I take lots of other supplements, so maybe its something else?

To assist the D I take 22.5mg zinc (mineral bound S. cerevisiae), 1500 mag L-threonate, 425mg Malic Acid Mag, active bio B (riboflavin25mg,b6 10mg,folate 2000mcg, b12 1000mcg, Betaine Anhydrous(trimethlglycine 500mg)

Are there supplements to help get rid of the ear ringing? Ginko I hear might.
I live in socal, lots of sun and eat healthy, so I will cut out the D3 and see if there is an improvement then add back in? And I will get a test done to see about the D level. Thank you as always for the work you are doing!

Reply

Mr Fisch
June 7, 2019

Hi, David

I noticed that no matter which dosage of D3 I take my average heart rate rest raises around 17bpm. From a Raymandor UVB lamp at 6 minutes per week to 2K IU D3 perday. Is there an issue I should remedy or do I take the hit?

Reply

    David Tomen
    June 10, 2019

    Mr Fisch, my area of expertise is with the human brain. Hopefully a heart expert reading this comment thread will chime in and give you some advice.

    Reply

deepak sadhwani
January 12, 2019

hey david your grace,
i have taken 8 pills of d3 60000iu on weekly basis up to 2 month d3 with k2 as m k7 200mg, level was low 28, now i am thinking to take d3 5000iu as daily dosage along with k2 once in two days, just want to know what is your opinion on taking 5000iu daily dosage, i use sesame oil and ghee after d3 pill

Reply

    David Tomen
    January 12, 2019

    Deepak, are you saying with your current dosage your 25-hydroxyvitamin D levels are 28 nhmol/L?

    Reply

      deepak sadhwani
      January 15, 2019

      no sir it was before taking 60k iu dosage then i took 8 pills of 60k on weekly basis in 2 month and now i am taking 5k iu with k2 one pill of k2 as mk7 100 mg in two days as per you this dosage safe with ?

      Reply

        David Tomen
        January 15, 2019

        Deepak, according to the Institute of Medicine here in the USA you should be OK with that dosage of Vitamin D. They found that toxic effects only showed up with doses of 40,000 IU daily after 12 weeks.

        Reply

deepak sadhwani
November 17, 2018

hey david,

my d3 level is 28 as per you how much vitamin d3 should i take daily please suggest me

Reply

    David Tomen
    November 17, 2018

    Deepak, Vitamin D3 is fat-soluble which means your body stores is rather than excreting excess in urine. I’m NOT a doctor so please keep that in mind. But my layman’s understanding is using 5,000 IU every 2 – 3 days should be safe. But I would recommend getting your “25-hydroxyvitamin D” levels checked occasionally.

    And keep in mind the D3 is ‘fat-soluble’ which means it should be taken with a meal containing healthy fats or a tablespoon or unrefined coconut oil and extra virgin olive oil.

    Reply

      deepak sadhwani
      November 19, 2018

      thank you david,

      david i think my d3 level is insufficient do you think that i should go with high dosage like 5000iu daily, it is 28 (25 hydroxy ) level, and i would be very greatful to know that can i use (ghee) instead of coconut oil or olive oil i am from india so my mom get pure ghee, and i have not enough money to buy it my supplement covers my whole money i am student now please, just know about high dosage daily like 5000iu daily and daily using of ghee half spoon twice after taking d3
      thank you for you love and support
      your grace 🙂

      Reply

        David Tomen
        November 19, 2018

        Deepak, I personally take 5000 IU of Vitamin D daily and have not had issues. Of course, the I suggest getting tested now and again just to make sure you are not overdoing it. And yes, ghee is a great alternative for a healthy fat.

        Reply

deepak sadhwani
November 17, 2018

hey david your grace,

david actually i am having little money issue, i got now foods product 5000ui it is more cheaper than 2000iu, so i am thinking to buy 5000iu per pill, it would really be very good for my budget, so i want to ask can i take 5000iu once in two days it would be healthy and safe call please give your precious reply thank you

Reply

John
August 30, 2018

Vitamin D reduced anger and irritability at 10,000 IU/day. Less than that did not work as well. Thanks.

Reply

    Suyash
    June 14, 2023

    Thats so true

    Reply

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