Vitamin D: Do You Really Need To Supplement? Part Two

In our previous blog post, we looked at what vitamin D does in our body and why it is important, but how do we properly assess vitamin D status and how do we know if supplementation is truly necessary? Why is this important? Supplementing with vitamin D is an excellent way to correct a deficiency, or insufficiency, that has been diagnosed by a healthcare practitioner. However, supplementing without repeated monitoring by your healthcare practitioner can be dangerous. 

Vitamin D is a fat-soluble vitamin, meaning that it needs dietary fat to be properly absorbed and that in excess it will be stored in our fat cells. This can be dangerous because this means that vitamin D will be stored longer in the body, making it easier to reach toxic levels if supplementing at high levels without true need. 

How Is Vitamin D Level Assessed?

Vitamin D levels are assessed by checking plasma levels of 25-OH D3 (calcidiol) in circulation, which is a better indicator of nutrient status than 1,25-OH D (calcitriol). Many people have access to their lab results via online health portals making it easy to compare your lab results with these ranges.

The current ranges for serum concentrations used to determine vitamin D levels are:1

<30 nmol/L   (<12 ng/mL)    Deficiency

<50 nmol/L   (<20 ng/mL)    Inadequate for bone and overall health

>50 nmol/L   (> 20 ng/mL)   Adequate

>125 nmol/L (>50 ng/mL)    Excess and potential adverse effects,

          especially at >150 nmol/L (>60 ng/mL)

500 nmol/L  (200ng/mL)    Toxicity

What Are The Symptoms Of Deficiency?

Rickets and osteomalacia are the two conditions that are directly associated with vitamin D deficiency.

Rickets

This condition is seen in children who have chronic low vitamin D levels and can cause a number of bone formation issues such as:

• Delayed growth

• Enlarged wrists, knees, and ankles

• Bowed legs/curved bones

• Spinal deformities

• Delayed tooth eruption

• Rachitic rosary (boney necklace)

• Soft spot slow to close

In addition to bone structure issues, vitamin D deficiency puts children at increased risk for infection.

Osteomalacia

In adults with chronic low vitamin D levels the “softening” of bone, called osteomalacia, increases a person’s risk for developing osteoporosis and bone fractures. This is because vitamin D is important to calcium absorption and low levels decrease calcium absorption in the intestine and increases calcium resorption from the bone, weakening the bone through demineralization.  Additionally, the three bones in our middle ear (malleus, incus, and stapes) are also impacted by low vitamin D levels which can lead to hearing loss and ringing in the ears.

Multiple Sclerosis, autoimmunity, diabetes, obesity, hypertension, depression, and fatigue are also connected with low vitamin D levels, although their direct connection is less understood. 

People Who Are At Risk for Deficiency And May Need To Supplement.

The most common cause, and risk factor, for vitamin D deficiency or insufficiency, is found in those who lack sun exposure.2

Sunlight exposure can be limited by

• Weather 

• Inability for outdoor activity

• Indoor job

• Use of sunblock

• Geographic location

  • North of 42° latitude → especially from Oct. - Mar.

  • North of 40° latitude → especially from Jan. and Feb.

Fortunately, adequate sunlight exposure can meet requirements in most people

Other risk factors are:

• Breast-fed infants

• People with darker skin complexions

• People who have undergone gastric bypass surgery

• Fat malabsorption issues3

  • Liver Disease

  • Cystic Fibrosis

  • Celiac

  • Crohn’s

  • Ulcerative Colitis

If the body cannot absorb fats, then fat-soluble vitamins like D, A, E, K are likely to be deficient.

• Vegans - many high quality sources of vitamin D in the diet come from animal products and fortified milk and dairy products. 

• Elderly

  • Dietary deficiencies

  • Lack of sun

  • Decreased ability to synthesize vitamin D in skin

• Chronic kidney disease/failure

  • If the kidneys are damaged or not working properly, they will not be able to activate vitamin D

• VDR SNPs - there are 2 types of vitamin D receptors (VDR)

  • Membrane VDRs

    • Located on the cell surface

  • Nuclear VDRs

    • Members of supergene family nuclear receptors

People who have Vitamin D Receptor Single Nucleotide Polymorphisms have greater difficulty maintaining adequate vitamin D levels without supplementation, due to how their body metabolizes the vitamin. Some people have trouble maintaining adequate levels even with supplementation. Typically, this will be the person who no matter how hard they try, their vitamin D levels stay frustratingly low.

What Are The Symptoms Of Toxicity?

It is virtually impossible to overdose on vitamin D through sun exposure, or through the diet. Vitamin D toxicity is directly associated with ingesting large amounts of supplemental vitamin D,4 since it is fat-soluble and hangs out in the body longer than water-soluble vitamins.

Symptoms of toxicity

• Headache

• Nausea

• Depression

• Fatigue

• Vomiting

• Constipation or diarrhea

• Calcification of soft tissues

• Hypercalcemia: 

  • hypothyroid like symptoms (calcium inhibits thyroid hormone)

  • excessive thirst/urination

  • muscle aches

  • memory loss (brain fog)

  • hearing difficulties

  • restless leg syndrome

  • muscle weakness

  • bone spurs, kidney stones, calcific tendonitis.

• What Is The Recommended Dietary Allowance (RDA) For Vitamin D? (same for male and female)
  

  0-12 months 10 mcg (400 IU) Adequate Intake (AI)

  1-70 years 15 mcg (600 IU) RDA

  >70 years 20 mcg (800 IU) RDA

  Pregnancy/

  Lactation 15 mcg (600 IU)

  What Is The Tolerable Upper Intake Level (UL) For Vitamin D? (same for male and female)

  0-6 months 25 mcg (1000 IU)

  7-12 months 38 mcg (1500 IU)

  1-3 years 63 mcg (2500 IU)

  4-8 years 75 mcg (3000 IU)

  9 + years 100 mcg (4000 IU)

  Preg/Lac 100 mcg (4000 IU)

  250 mcg (10,000 IU) daily can lead to toxicity in adults

  Things To Try Before Jumping into Full Supplementation

  First, and foremost, get tested. Make sure you actually need to supplement, due to deficiency or insufficiency. This will prevent you from taking in toxic amounts of vitamin D and save your money as well!

  Second, make a conscious effort to spend more time outside on a daily basis. Sunlight is the easiest, cheapest, and safest way to get vitamin D (as long as you are safe about your time exposed to ultraviolet rays).

  Although the sun is the main source of vitamin D, there are some food sources that can support our vitamin D levels, especially during the cooler months up north. Two forms of vitamin D are supplied through our foods: Cholecalciferol (D3) and Ergocalciferol (D2); D3 is found in animal sources while D2 is found in plant sources. The vitamin D form supplied by UVB rays and animal sources is more bioavailable than D2, which must first be converted from Ergosterol.  

  Food sources of vitamin D:

  • Cod liver oil

  • Beef 

  • Veal

  • Liver → vitamin D is mainly stored in the liver so it is a good source

  • Egg yolk

  • Saltwater fish

    • Sardines

    • Tuna

    • Salmon

  • Fortified foods (often in the form of D2 because it is more affordable)

    • Milk and dairy

    • Orange juice

    • Cereals

    • Mushrooms (D2, D3, D4) - specifically mushrooms that have been exposed to high levels of UV rays

  • In plants

    • Ergosterol (previtamin D2) is converted to ergocalciferol (D2)

      • Ergocalciferol is sold commercially

  What If I Need To Supplement?

  For some people supplementation is inevitable due to a health condition, geographical location, or lifestyle factors. The Endocrine Society recommends that adults supplement with 1000-2000 IU daily and 1000 IU daily for children.5 However, it is still good practice to monitor vitamin D levels with your healthcare practitioner to assure they are within a healthy range. Additionally, individuals with deficiency or chronic health issues must supplement under a doctor’s guidance to ensure they are supplementing adequately and safely. 

  When supplementing with vitamin D is it also important to consider how to get the best result by supporting intake with other nutrients. Some nutrients to consider, especially when taking high doses of vitamin D, are:

  • take 200 mcg of Vitamin K2 as MK7 for every 5,000 IU of D

  • take 5mg of Mg per pound of body weight daily

  
  As always, communicate your supplementation and any changes with your healthcare provider.

  References

  1. National Institutes of Health; Office of Dietary Supplements, Health Professional Fact Sheet. Updated March 26, 2021. Retrieved at:

  https://ods.od.nih.gov/factsheets/VitaminD-health%20Professional/ 

  2. A. R. WEBB, L. KLINE, M. F. HOLICK, Influence of Season and Latitude on the Cutaneous Synthesis of Vitamin D3: Exposure to Winter Sunlight in Boston and Edmonton Will Not Promote Vitamin D3 Synthesis in Human Skin, The Journal of Clinical Endocrinology & Metabolism, Volume 67, Issue 2, 1 August 1988, Pages 373–378, https://doi.org/10.1210/jcem-67-2-373

  3. Pappa HM, Bern E, Kamin D, Grand RJ. Vitamin D status in gastrointestinal and liver disease. Curr Opin Gastroenterol. 2008;24(2):176-183. doi:10.1097/MOG.0b013e3282f4d2f3

  4. Asif A, Farooq N. Vitamin D Toxicity. [Updated 2021 Apr 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557876/

  5. Michael F. Holick, Neil C. Binkley, Heike A. Bischoff-Ferrari, Catherine M. Gordon, David A. Hanley, Robert P. Heaney, M. Hassan Murad, Connie M. Weaver, Evaluation, Treatment, and Prevention of Vitamin D Deficiency: an Endocrine Society Clinical Practice Guideline, The Journal of Clinical Endocrinology & Metabolism, Volume 96, Issue 7, 1 July 2011, Pages 1911–1930, https://doi.org/10.1210/jc.2011-0385