This post contains affiliate links. For more information, please see our Affiliate Disclosure page.
It’s that time of year again when even I start to get “depressed.” Here in the mid-Atlantic area, the sun is getting lower, the days are getting shorter, and the nip from Old Man Winter is starting to infect the air. Soon, many of us won’t even see the sun during the day – reporting to our modern caves (aka, offices) before it rises and once again hiding before we can escape. Even those of us who are lucky enough to work outside may be hit with the “sappy’s” – required now to armor ourselves with multiple layers of insulation to guard against the diminishing temperatures.
What many of us don’t realize is that we need the sun to thrive, and when we deprive ourselves of it, we get SAD. Yeah, SAD. Seasonal Affective Disorder – it’s a thing. [1] And I’m sure we’ll start seeing advertisements for the flu shot to combat yet another “cold season,” too.
I submit, however, that we suffer more from Vitamin D deficiency season, instead. Albeit even that’s a bit of a misnomer. See, Vitamin D isn’t technically a vitamin in the first place – it’s actually a oil soluble hormone (more specifically, a steroid) who’s primary function is cell management. [2]
With numerous studies now showing how integral Vitamin D is in warding off everything from Cancer to Diabetes, depression and psoriasis, even overall mortality; [3] not to mention how essential it is in DNA replication, gene expression and the function of the immune system – maybe we should start to prioritize getting healthy doses of this “sun vitamin.” Oh, and by the way…you can really only get sufficient amounts of this stuff from exposing your bare skin to sunlight and/or by taking a Vitamin D supplement – not from food. [4]
That’s it! We must all march on Florida in a naked migration to the sunshine state!
Okay…maybe not.
Before we continue, however, we should probably define what we mean by “Vitamin D.”
There are actually 5 discrete forms of “Vitamin D,” as noted by a numerical subscript;
| Vitamin D1 | : ergocalciferol with lumisterol |
| Vitamin D2 | : ergocalciferol (made from ergosterol) |
| Vitamin D3 | : cholecalciferol (made from 7-dehydrocholesterol) |
| Vitamin D4 | : 22-dihydroergocalciferol |
| Vitamin D5 | : sitocalciferol (made from 7-dehydrositosterol) |
However, when someone mentions “Vitamin D,” they are likely referring to either or both of D2 and/or D3. D2 being the plant-derived version, and D3 being the human-synthesized form. That said, you should mostly be concerned with getting adequate amounts of D3, as it is more stable, more natural, more potent, and has a higher bioavailability. [5]
Dr. Alan Gaby asserts,
“If you take ergocalciferol, or “vegetarian” vitamin D, be warned. Ergocalciferol [D2] is not vitamin D, but a vitamin D-like patent drug whose patent has expired. It does not normally occur in the human body and is probably a weak agonist at the receptor site, meaning it may actually partially block vitamin D actions. Ergocalciferol is the villain in most of the reported cases of toxicity in the world’s literature. All bets are off in terms of measuring blood levels if you take ergocalciferol. Some of the labs can pick it up, and some can’t. Don’t take ergocalciferol; it is not vitamin D.”
Whenever you see, “Fortified with Vitamin D,” or “a good source of Vitamin D,” as many companies like to do on their packaging – they are talking about D2. Yes, milk and cereals (when fortified) are a good source of D2, but we’re after D3!
That said, for the rest of the article we’ll be using “Vitamin D” to mean D3.
How does Vitamin D work?
As mentioned above, over 90% of Vitamin D in your body is created from skin exposure to UV-B light. As the radiation from the sun penetrates your skin, it confronts a type of cholesterol (7-dehydrocholesterol) and breaks it down into the pre-vitamin (or inactive) form of Vitamin D (Vitamin d3, or cholecalciferol). Once absorbed into your blood stream, it makes it’s way to the liver and then the kidneys where it’s further activated into what we know as Vitamin D3 (calcitriol). [9] [10] Finally, it can be transported to organs throughout the body to where it can treat, prevent and even reverse a number of daily ailments – from high blood pressure, to back pain, to arthritis.
It’s like we’re some kind of super-human plant or something! Through a type of human-photosynthesis, our body uses the sun’s energy to create health!
Take note to the process above, though! There are a lot of moving parts, and should any one of those parts break down (e.g. fatty or disrupted liver function, compromised kidneys, inadequate safe exposure to sunlight, et cetera), you WILL become deficient in Vitamin D. Why? Because you can’t make it.
And don’t worry about getting too much from that fiery orb. Although skin damage IS a real threat from unsafe sun exposure, a “VitD” overdose isn’t one of them. While UV-B radiation creates Vitamin D, UV-A radiation eliminates it. So, there are protective mechanisms built into nature which assist our bodies in balancing these things out! If you’ve read some of my other articles on Potassium and/or Magnesium, you’ll come to realize quickly the importance of balance.
Vitamin D is fat-soluble – meaning, fat is integral to the functionality. Remember above, how we mentioned cholesterol? Well, without that healthy fat (yes, I said cholesterol is healthy), Vitamin D can’t be made. It also means that Vitamin D can’t be absorbed without bile (and a healthy gallbladder). Being fat-soluble also means that the body can and will store it to be used later.
Be careful, though. Fat-soluble vitamins can accumulate inside the body and reach toxic levels if not careful. Unlike water-soluble vitamins (like the B Vitamin complex and Vitamin C, which are readily excreted through the urine), fat-soluble vitamins take much longer to “process” through your system. Therefore, deficiency symptoms take a long time to manifest (sometimes months to years). This also means that rectifying any deficiencies will take some time as well, so be patient and stick with it.
What does Vitamin D do?
Throughout your body there are millions of cells. Each one of those cells have a Vitamin D receptor on it. Should a cell become damaged or mutate, Vitamin D can plug into that receptor and communicate with it – providing instructions on how the cell can repair itself in the case of cell damage, or instructing the cell to destroy itself if the cell has dangerously mutated. Without enough Vitamin D, damaged and mutated cells will multiply and spread throughout the body – leading to disease. [7] With accelerated rates of metabolic diseases, liver and kidney diseases, heart disease and cancer, I’m sure it wouldn’t [now] surprise you that over 1/3 of the population is deficient in Vitamin D. [11] I’ve even seen numbers as high as 95% of senior citizens and 85% overall of Americans having Vitamin D levels far below optimal levels. [12] It just depends on which numbers you use, really.
Vitamin D is most touted for it’s role in Calcium and Phosphorous balance and their combined efforts the proper development and maintenance of bone.
In the intestines, Vitamin D controls the absorption of these minerals into the body. That means, osteoperosis and other conditions commonly associated with lack of Calcium, might not be an issue with Calcium at all – rather, it may be that your body can’t absorb it due to a deficiency in Vitamin D. While normally absorbing between 60-80% of dietary calcium, a deficiency in Vitamin D may cause that to fall to as low as 15%.
In the kidneys, Vitamin D controls the re-absorption of Calcium from the body to be excreted.
In the bones, Vitamin D regulates the activity of cells responsible for the remodeling and rebuilding of bone.
In the parathyroid (a group of glands in the neck responsible for controlling the body’s Calcium level), Vitamin D manages cellular and hormonal processes, as well as sensitizing the parathyroid to Calcium that’s already in the blood. Without Vitamin D, the feedback loop between the parathyroid and multiple other systems/organs simply can’t function properly – further adding complications to gut health, bone stability and kidney function.
Researchers are now finding just how important Vitamin D is to the cellular health of all these organs, glands and systems throughout the body:
| Vitamin D promotes cellular health within | |||
| Skeletal Muscle |
Heart | Lungs | Pancreas |
| Kidneys | Ovaries | Testes | Central Nervous System |
| Skin | Bone | Teeth | Intestines |
| Parathyroid | Skeletal System |
Liver | Blood |
Why should I care about Vitamin D?
Hopefully, I’ve made that pretty clear by now, but… With Vitamin D being so crucial in the proper expression of genes and cellular health, there’s no wonder a deficiency in Vitamin D is commonly associated with a great number of illnesses and even death.
| Issues Commonly Associated with Vitamin D Deficiency | |||
| Cardiovascular Disease |
Stroke | Pre-Eclampsia/ Eclampsia |
Infections |
| Flu | Cold | Type 2 Diabetes |
Type 1 Diabetes |
| Metabolic Syndrome |
Poor DNA Repair |
Hypertension (High Blood Pressure) |
Muscle Weakness |
| Arthritis | Cancer | Osteoporosis | Rickets |
| Other Inflammatory Diseases |
Heart Disease |
Autoimmune Diseases |
Infectious Diseases |
| Osteomalacia | Musculoskeletal Pain |
Skin Pigmentation |
Ecsema |
| Inflammatory Bowel Disease |
Depression | Cognitive Impairment |
Alzheimer’s |
| Crohn’s Disease |
Ulcerative Colitis |
Obesity | Multiple Sclerosis |
| Asthma | Schizophrenia | Depression | Infertility |
How do I know I’m deficient in Vitamin D?
You are. Period. I’d bet money on it.
Optimal Vitamin D levels are somewhat controversial, with some siting numbers as low as 30 ng/ml. The correct test your doctor needs to order for inactive Vitamin D is 25(OH)D, also called 25-hydroxyvitamin D. This test measures the concentration of calcifediol (or Vitamin d3 after it’s gone through your liver. Your doctor may (and you should also request he/she to) order the 1,25(OH)D blood work for measuring active Vitamin D. This test measures the concentration of calcitriol (the fully activated form of Vitamin D after it’s gone through the kidneys).
The former is considered a much better marker of overall Vitamin D serum levels; however, a comparison between the two will give a better overall picture of what the underlying issue may be. [19]
For example, [21]
If you have low levels of both, that may be a result of not getting enough Vitamin D in your diet but most likely not getting enough sunlight.
If you’re low in inactive levels but high in active levels, that may be indicative of a parathyroid complication or other organ/gland damage.
25(OH)D Lab values of 20-56 ng/ml are considered “normal,” but this doesn’t mean ideal. These are estimates based on when disease can start – meaning, there is a correlation between numbers lower than this and folks having disease. This doesn’t mean that you will be healthy at this level.
From sources I trust, the optimal range for general health appears to be somewhere between 50 and 55 ng/ml, and should never be below 32 ng/ml. Any levels below 20 ng/ml are considered seriously deficient. [19] That said, higher levels are recommended to fight disease, cancer, et cetera. [14]
| Vitamin D Levels – through blood tests | |
| Deficient: | < 50 ng/ml |
| Optimal: | 50 – 70 ng/ml |
| Treat Cancer and Heart Disease: | 70 – 100 ng/ml |
| Excess: | > 100 ng/ml |
Although ng/ml is used to classify the concentration of Vitamin D in your blood, a more common way to look at Vitamin D (when it comes to amounts one can make or consume), is by International Units (IU). The “general rule of thumb” is, serum concentration increases by 10ng/ml for every 1,000IU. [18] [20]
Also, for sake of completeness, 40IU = 1 mcg.
The easiest way to tell if you’re deficient is a blood test, but here are some symptomatic signals you may be deficient in Vitamin D.
| Vitamin D Deficiency Symptoms | |||
| Dry Skin |
Depression | Aching Bones |
Blood Sugar Irregularities |
| Head Sweating |
Getting Infections Easily/Often |
Getting Sick Easily/Often |
Nervousness |
| Fatigue | Bowel Irregularities |
Bone Pain |
Impaired Healing |
| Bone Loss |
Hair Loss |
Muscle Pain |
Overall Poor Health |
Why would my Vitamin D levels be low?
Because Vitamin D is primarily synthesized by bare skin exposure to the sun, key factors in Vitamin D deficiency naturally pertain to the sun and safe, quality exposure to it.
- Insufficient bare skin exposure to the sun
- Indirect sun exposure (latitude and altitude)
- Age – with Vitamin D deficiencies more common in the elderly
- Race (more specifically skin color) – as darker skin colors make it harder to absorb the sun’s rays
- Tan – darker tans make it harder for UV-B radiation to penetrate the skin
- Use of sunscreen
- Time of day
- Seasons
- Weather
- Environmental Pollution
- Diets low in fatty fish
According to one article, [13]
“The major cause of vitamin D deficiency globally is an under appreciation of sunlight’s role in providing humans with their Vitamin D3 requirement. Very few foods naturally contain vitamin D, and those that do have a very variable vitamin D content.”
Just remember, that your body uses Vitamin D in almost every cell of the body, so if you’re not making an effort to replenish your Vitamin D supplies, you will become deficient and your health will suffer.
Other conditions that may cause irregular Vitamin D values include, [22] [23]
- Bowel dysfunction and dysbiosis
- Gallbladder issues (or removal)
- Acid blocking medications
- Reduced Liver function
- Gastric bypass surgery
- Compromised Parathyroid function
- Adrenal stress
- Compromised Kidney function
- High levels of cortisol (stress) blocks absorption
How can I prevent Vitamin D deficiency?
As stated above, many factors have an affect on the “quality” of sun exposure, so it’s really hard to put numbers on it. But let’s try.
For example, [16]
A dark-skin person may require twice the length (time) of exposure than a fair-skin person.
The same person may require 2-3 times the length (time) of exposure in winter as they would in summer.
The same person in Chicago may require 10 times the length (time) of exposure as if they were in Miami.
At latitudes above approximately 35 degrees, there is minimal (if any) Vitamin D produced by the skin.
So, if you live north of the 35th parallel (which the majority of the US population does); if it’s not summer time (which it isn’t 75% of the year); and if you aren’t running around 1/2 naked (which, ya know what – I’m gonna leave that one alone)… Yeah, chances are you are Vitamin D deficient. You could move further south, shed some clothes, or get a safe tanning bed (or light that emits UV-B light), but I’m guessing those probably aren’t in the cards.
There are some dietary sources (albeit somewhat trivial), but you can have some affect by consuming healthy foods. Here are a few examples: [17]
| Foods High in Vitamin D | |||
| Cod Liver Oil (1,360IU per Tbsp) |
Wild Caught Salmon (447IU per 3oz) |
Mackerel (306IU per 3oz) |
Tuna (154IU per 3oz) |
| Fortified Milk (124IU per 1 cup) |
Sardines (47IU per 2) |
Beef Liver (42mg per 3oz) |
Eggs (41IU per 1) |
Mushrooms are the only vegetarian source of Vitamin D, but they must be exposed to the sun. As most of them are grown indoors, leaning on them as a reliable source of Vitamin D can be iffy. Some health food stores are carrying mushrooms that have been “boosted” by ultraviolet light, however. [24]
Just remember, if you have diminished gall bladder function, liver function or intestinal permeability (leaky gut or digestive distress), you won’t be able to break down and absorb fat-soluble nutrients (e.g. Vitamin D, along with Vitamin K, A and E).
Should I take a Vitamin D supplement?
We already went over how the majority of people are deficient, and it’s not really feasible to get what you need via diet – even if you’re consuming a Heading Healthy diet.
So, in a word. Yes.
However, there are 2 main caveats to this.
You can overdo it!
Although the threshold for Vitamin D has not been established (seriously, they are all over the map!), published cases of toxicity involving hypercalcemia in which the vitamin D dose and the 25-hydroxy-vitamin D levels are known, all involve an intake of ≥40,000 IU per day. [25]
The Recommended Daily Allowance (RDA) for Vitamin D from the Institute of Medicine (IOM) is 600 IU, however the Endocrine Society states up to 2,000 IU [39] [40] The American Geriatrics Society recommends an average of 4,000 IU of Vitamin D per day from all sources.
The Institute of Medicine (IOM) has set a tolerable upper limit (UL) of 4,000 IU per day. [26] This number, however, comes from the same data presented to the Endocrine Society (who suggest a UL of 10,000IU). [37] The Institute of Medicine simply applied a .04 safety factor to the data. [38]
One important note here about Tolerable Upper Limit UL! As defined by the National Institute of Health, “Tolerable Upper Intake Level (UL) is the maximum daily intake unlikely to cause adverse health effects.” This commonly misinterpreted (even misrepresented) as the point above which adverse effects begin to accumulate. That is simply not true. The point at which adverse affects begin to accumulate is called the No Observed Adverse Effect Level (NOAEL). This is defined as a level at which a healthy person can take for the rest of their life and not see any adverse effects. The two are technically and wildly different. [42]
That said, most of my research has found 10,000 IU per day to be a safe and effective dose for supplementation. [27] [28] [29] [30] I’ve even seen where physicians subscribe up to 50,000 IU to reverse extreme deficiencies. However! This leads to caveat #2.
You must take it with Vitamin K2!
Increasing your levels of Vitamin D will also increase your levels of Calcium in the body, as Vitamin D boosts the absorption of Calcium by more than 20 times. Too much calcium in your blood can weaken or induce pain in your bones, create kidney stones, produce headaches and fatigue, cause excessive thirst and urination, produce abdominal pain, constipation, vomiting, nausea, decreased appetite, and interfere with how your heart and brain work. [31] [32]
Notice, I underlined “in your blood.” In order for the Calcium to be used effectively and to be transported where it’s needed most (e.g. hard tissues like bones, teeth, et cetera) you need Vitamin K2.
Although Vitamin K1 is primarily used by the body as a clotting agent, Vitamin K2 works with Vitamin D to transport Calcium into the bones and out of the blood stream and joints – shown to even “elasticize” your arteries. [33]
If you do more research, you’ll also find that supplementing with Calcium doesn’t help osteoporosis or other bone disorders. In fact, Calcium supplements appear to have a negative risk-benefit effect due to increased gastrointestinal side effects (including a doubling of hospital admissions for these problems), a 17% increase in kidney stones and a 20-40% increase in risk of heart attack. [43] Why? Because we all get enough Calcium! However, we don’t get enough Vitamin D3 and Vitamin K2 to effective and efficiently use that mineral!
Remember! If you’re taking Vitamin D, you’re creating an increased demand for Vitamin K2. [34]
How much Vitamin K2 should you take with Vitamin D3? One resource mentions 100-200 mcg of Vitamin K2 for ever 1,000IU of Vitamin D, while another suggests 100 mcg Vitamin K2 for ever 10,000IU of Vitamin D.
I, personally, have been supplementing with 10,000 IU of Vitamin D along with 100 mcg of Vitamin K2 for almost a year – with good results. I’ve also had experience with individuals reducing allergies and asthma with that same dosage. On the flip side, I’ve also seen people forget to take K2 with the D3, which led to abdominal pains, bone soreness and overall lethargy. It just goes to show you that you need to be aware of what you’re body is telling you at all times.
Listen to your body, and do your research!
When you look for supplements, remember to do your homework. Some supplements can have impurities and toxins, which you’re trying to stay away from. It’s important to get them from trusted sources. One great source is BulkSupplements.com, a new sponsor of Heading Healthy!
Although I generally get my Vitamin D3 and Vitamin K2 when it’s on sale at The Vitamin Shoppe, if I had to recommend 1 source, it would be Dr. Bergs D3/K2 blend. It takes the guess work out of it, and comes in 1 convenient pill that provides exactly what you need. At minimum, it’s recommended to take 1 of these every day. Your needs may be different, however, and positive effects may require taking up to 4 per day. [36]
   |
| Vitamin D3 & K2 |
| Dr. Berg’s |
| Dr. Berg’s Vitamin D3/K2 blend comes in the desired ratio (10,000IU/100mcg) and has added bile salts for better absorption.
Note: Previous versions may be enriched with red yeast. |
As always, consult with your doctor!
What’s the bottom line about Vitamin D?
Vitamin D3/K2 is one of four key supplements I recommend to almost everyone – it’s that important. The other three (by the way) are Probiotics, Digestive Enzymes and Omega-3 Fish Oil.
With Vitamin D3 being so integral in creating health and warding off disease, it just makes sense. There are very few downsides with LOTS to gain. In fact, I would argue, if you’re not supplementing with Vitamin D3, you’re depriving yourself of health – hands down. It would be the first “next step” after I’ve checked all the boxes on the Heading Healthy Road Map.
Most of us are deficient in Vitamin D3 due to our societal changes (e.g. working inside, geographical hot spots, et cetera), but we have evolved to harness nature. Unless you make a concerted effort to get outside and soak up the sun (and live in an area that offers quality opportunities), you’re denying yourself the right to be healthy.
Our bodies are intelligent and self-regulating – they don’t just do things by accident. All life needs energy. After oxygen, water and food – sunlight is by far the most important nutrient. Take some time to get out there. Get out from behind your desk and take a walk. Feel the sunshine on your face and bask in the energy of the sun. If you can’t, maybe consider taking a vacation to somewhere you can. 😉 Your body will thank you!
For a list of other supplements and products recommended by Heading Healthy, please visit our Recommendations Page.
Don’t know where to start? Check out our Heading Healthy Road Map!
[1] https://www.verywellmind.com/what-is-seasonal-affective-disorder-1065408
[2] https://en.wikipedia.org/wiki/Vitamin_D
[3] https://www.ncbi.nlm.nih.gov/pubmed/24414552
[4] https://www.vitamindcouncil.org/about-vitamin-d/how-do-i-get-the-vitamin-d-my-body-needs/
[5] https://www.betterbones.com/bone-nutrition/what-is-the-difference-between-vitamin-d2-and-vitamin-d3/
[6] https://www.youtube.com/watch?v=J1sTYuL-QsU
[7] https://www.youtube.com/watch?v=MtUgi9wZGXU
[8] https://www.youtube.com/watch?v=4VlXGA1FnSk
[9] https://www.cdc.gov/nutritionreport/99-02/pdf/nr_ch2b.pdf
[10] https://www.youtube.com/watch?v=onSPZ0aBUKM
[11] https://www.betterbones.com/bone-nutrition/cdc-report-on-vitamin-d/
[12], [29], [34] https://www.mercola.com/article/vitamin-d-resources.htm
[13] https://www.ncbi.nlm.nih.gov/pubmed/18290718
[14] https://articles.mercola.com/sites/articles/archive/2013/12/22/dr-holick-vitamin-d-benefits.aspx
[15] https://www.healthline.com/nutrition/vitamin-d-deficiency-symptoms#section1
[16] https://www.vitamindcouncil.org/about-vitamin-d/how-do-i-get-the-vitamin-d-my-body-needs/
[17] https://draxe.com/top-10-vitamin-d-rich-foods/
[18] https://www.medscape.com/viewarticle/589256_8
[19] https://articles.mercola.com/sites/articles/archive/2008/06/28/if-you-choose-to-take-oral-vitamin-d-how-much-should-you-take.aspx
[20], [39] https://ods.od.nih.gov/factsheets/Vitamin%20D-HealthProfessional/
[21], [22] https://www.youtube.com/watch?v=rEgdyd8OC00
[23] https://www.youtube.com/watch?v=kJegLw2qtPc
[24], [27] https://draxe.com/vitamin-d-deficiency-symptoms/
[25] https://www.ncbi.nlm.nih.gov/pubmed/10232622
[26] https://www.ncbi.nlm.nih.gov/pubmed/21118827
[28] https://www.youtube.com/watch?v=M2ne0tlBlu4
[30] https://www.drjohnbergman.com/vitamin-d/
[31] https://www.mayoclinic.org/diseases-conditions/hypercalcemia/symptoms-causes/syc-20355523
[32] https://www.healthline.com/health/hypercalcemia#symptoms
[33], [35] https://www.youtube.com/watch?v=-gei4_8ZAvo
[36] https://youtu.be/qGwDTixHCZg
[37], [40] http://press.endocrine.org/doi/10.1210/jc.2011-0385
[38], [43] https://www.youtube.com/watch?v=B9SNfrE7P1s
[41] https://scpa.memberclicks.net/assets/journalce/vitamin%20d-updated.pdf
[42] https://www.ncbi.nlm.nih.gov/pubmed/15979222
[43] https://www.ncbi.nlm.nih.gov/pubmed/26174589
Featured Photo by Andreas Dress on Unsplash
