In the second installment of our 2-part blog series, you’ll get a deep dive into the relationship between Vitamin D and the hidden health trends you could be missing in your clients. Missed Part 1? Head on over to catch up here. Read on to discover the impact of Vitamin D on innate and adaptive immunity.

Firstly, let’s take a look at the chronic conditions associated with Vitamin D deficiency:

  • Bone metabolic disorders (osteoporosis, osteoarthritis)
  • Tumors
  • Cardiovascular disease
  • Hypertension
  • Diabetes and Metabolic syndrome
  • Neuropsychiatric disorders
  • Autoimmune diseases
  • Chronic skeletal pain
  • Depression (Seasonal affective disorder (SAD)

The most common manifestations of Vitamin D deficiency in adults include:

  • Depression,
  • Infection,
  • Pain (bone, pain, muscle pain)
  • Other: fatigue, infections, dysbiosis, cognitive impairment, statin intolerance/myalgia.

Why the assessment of optimal Vitamin D levels is so important

Assessing individual’s levels before starting supplementation protocol will help adjust the dose accordingly and avoid toxicity and potential side effects. Vitamin D is fat-soluble vitamin, thus it can bioaccumulate over time, and potentially become toxic at high levels. Almost all the FDX panels include Vitamin D biomarker assessment.

Keen to get started with identifying your clients’ hidden health trends and Vitamin D levels? Register as a Practitioner today to access our revolutionary blood and health reporting.

Here are some findings to consider regarding potentially toxic Vitamin D levels:

  • Research suggests that 25(OH)D levels > 80 ng/mL (200 nmol/L) can only be indicative of toxicity when accompanied by clinical manifestations and hypercalcemia.
  • Vitamin D intoxication only occurs when the circulating levels of 25(OH)D exceed 125 ng/mL [312 nmol/L].
  • Assessment for hypervitaminosis D is performed by measurement of serum 25(OH)D and serum Calcium levels.

Periodic assessment of serum 25-OH-vitamin D [25(OH)D] and serum Calcium are recommended to ensure proper Vitamin D levels for health maintenance and disease prevention. Testing serum 25(OH)D is important for assessment of Vitamin D absorption, compliance, and safety. Measurement of 1,25-dihydroxyvitamin (Calcitriol) is not recommended for the evaluation of Vitamin D status and can even be misleading.

Why you need to be looking at optimal Vitamin D levels to get the best results for your clients

Due to the recent discovery of vitamin D receptors (VDR) in tissues besides the gut and bone—especially in the brain, breast, prostate, and lymphocytes, it has been suggested that higher Vitamin D levels can provide better protection from chronic conditions such as diabetes mellitus, osteoporosis, osteoarthritis, hypertension, cardiovascular disease, metabolic syndrome, depression, several autoimmune diseases, and cancers of the breast, prostate, and colon.

  • Vitamin D Deficiency: Serum 25(OH)D levels less than 20 ng/mL (50 nmol/L.
  • Vitamin D Insufficiency: Serum 25(OH)D levels less than 40 ng/mL (100 nmol/L). Some studies showed that serum levels of PTH start to increase when 25(OH)D levels fall below 45 ng/mL (110 nmol/L) in elderly men and women, which indicates that in order to maintain physiologic suppression of PTH, serum levels of 25(OH)D need to be greater than 40 ng/mL (100 nmol/L).
  • Optimal Vitamin D Status: Serum 25(OH)D levels 40–65 ng/mL (100–160 nmol/L).
Source: [5] (IMAGE: Proposed normal and optimal ranges for serum 25(OH)D levels based on current research* * Modified from: Vasquez A. Integrative Orthopedics: Concepts, Algorithms, and Therapeutics. Houston; Natural Health Consulting Corporation. 2004: 417-419 with permission)

Who benefits the most from getting their levels tested?

Certain populations possess risk factors for Vitamin D deficiency:

  • Dark skin
  • Obesity
  • Malabsorption
  • Older age
  • IBD (inflammation & malabsorption)
  • Sun deprivation/overprotection (extensive use of SPF)
  • Use of anticonvulsants or prednisone derivatives (upregulate detoxification pathways in the liver, which leads to excretion of Vitamin D)

What are the best sources of Vitamin D?

Vitamin D can be obtained naturally from two sources:

  1. Sunlight (when Vitamin D3 is produced in the skin)

Human physiology was shaped by a natural environment with ample exposure to sunlight. Full-body exposure to ultraviolet light on clear days in equatorial latitudes can provide the equivalent of 4,000–20,000 IU of Vitamin D. A full-body sun exposure of approximately 30 minutes can produce up to 50,000 IU of Vitamin D in fair-skinned person, while a darker more pigmented skin type person would require 5 times longer duration of sun exposure to produce the same amount of Vitamin D.

  1. Dietary consumption: Vitamin D3 (cholecalciferol) and Vitamin D2 (ergocalciferol)

Vitamin D3 (cholecalciferol): One of the best dietary sources of vitamin D is cod-liver oil. However, the amount required to obtain a target dose (2,000 – 4,000 IU per day) would require consuming about three tablespoons of cod-liver oil, or over 15 capsules of most commercial preparations daily, which can become costly and affect compliance over time. Thus, the preferred way among health practitioners is supplementation with “pure” Vitamin D supplements which allows the dose to be tailored to the individual needs.

Other animal sources of Vitamin D3 include fatty fish, egg yolks, and liver.

Vitamin D2 (ergocalciferol). This form of Vitamin D is widely used in supplements and fortified foods. It also can be found naturally in some dietary plant sources such as shiitake mushrooms. Commercially, ergocalciferol is produced by irradiating fungi/yeast. Since ergocalciferol shows altered pharmacokinetics compared with D3 and possesses risk of contamination during its microbial production, it is thought to be potentially less effective and even more toxic than cholecalciferol. However, when it comes to supplementation with regular daily intake both Vitamin D2 and Vitamin D3 can be considered bioequivalent, because they both undergo identical metabolism in the liver.

It is worth remembering, however, that optimal clinical effectiveness of Vitamin D supplementation often depends on synergistic effect of diet, lifestyle, exercise, emotional health, and other factors.

Identifying the status of Vitamin D in our patients is as important today as it has always been. With an increasing public spotlight on this marker, and with clients keen to know what degree of protection they currently hold against the ravages the modern world has to offer – including COVID-19 – identification of Vitamin D status is now something clients are demanding.

FunctionalDX recognises this need and includes Vitamin D measurement as standard in all our major panels.

Ready to uncover your clients’ hidden health trends? Order your revolutionary blood and health reporting today.









[8] Vinood B. Patel, BSc, PhD, FRSC, Molecular Nutrition: Vitamins 2020