Your Essential Guide to Safe Vitamin D Supplementation

Alia Debs

Your Essential Guide to Safe Vitamin D Supplementation

Although sunlight is abundant in our countries, vitamin D deficiency appears to be prevalent. This is due to several factors: including limited sun exposure, indoor lifestyles, increased sunscreen use, and clothing that covers most of the skin. Moreover, dietary sources alone may not provide sufficient vitamin D for many individuals.

Vitamin D plays a crucial role in bone health, immune system function, and overall well-being. Insufficient vitamin D levels can lead to weakened bones, increased susceptibility to infections, and potential links to various chronic health conditions. Therefore, addressing vitamin D deficiency through safe supplementation or increased sun exposure when possible is essential for maintaining good health and preventing associated health issues.

Frequently asked questions

1- Is it true that vitamin D is considered a hormone?

Yes, vitamin D is considered a hormone because it functions as a hormone in the body, despite being classified as a vitamin. It plays a crucial role in various physiological processes and acts on multiple organs and tissues, similar to other hormones in the body.

2- Do I need vitamin D supplement?

Vitamin D deficiency is prevalent; however, before taking vitamin D it’s recommended to test 25(OH)D blood level . This blood test provides an accurate assessment of the vitamin stores, helps identify the need for supplementation, and help to determine an effective dose.

3- What increases the risk of vitamin D deficiency?

  • Poor oral intake or inadequate oral intake
  • Limited sun exposure (conservative style, indoor lifestyle)
  • Pancreatitis, inflammatory bowel syndrome (IBS), celiac disease
  • Bariatric surgery procedures
  • On medications (antiepileptic , liver disease)
  • Aging
  • Kidneu disease
  • Smoking

4- Is there an association between obesity and vitamin D deficiency?

Short answer is YES.

New studies are showing that obesity decreases the bioavailability of vitamin D. Parathyroid hormone (PTH), calcium, low vitamin D levels, and obesity are interconnected in a complex relationship. When vitamin D levels are insufficient, the body's ability to absorb calcium is compromised. This can lead to lower blood calcium levels, triggering the release of PTH from the parathyroid glands to raise calcium levels. However, in cases of obesity, vitamin D can become sequestered in fat tissues, reducing its availability for absorption. Consequently, this can result in a higher PTH secretion to maintain calcium levels. This intricate interplay underscores the importance of maintaining adequate vitamin D levels, especially for individuals with obesity, to help regulate PTH and calcium and support overall health.

**Bioavailability refers to at which the body can absorb and utilize vitamin D from a particular source

5- Can I correct vitamin D deficiency by diet alone?


Vitamin D content in most food is low except fatty fish like anchovies, herring, mackerel, black cod, salmon, sardines, bluefin tuna, whitefish, striped bass and cobia.

6- How much Vitamin D do I need?

This is based on 25(OH)D blood level.

It’s interesting to mention that taking 50,000 IU of vitamin D orally once weekly for 2-3 months or 3 times weekly for 1 month is safe when vitamin D deficiency is severe <10ng/ml

Once you correct the deficiency, it’s important to take a prevention daily dose of 2000 IU/day

It's always best to consult with a healthcare professional before starting any new supplement regimen to determine the most appropriate form and dosage of vitamin D for your individual needs.

7- How to choose the best supplement of vitamin D?

Vitamin D3 (cholecalciferol) is generally considered the most effective and preferred form of vitamin D when choosing a supplement.

However, if you have specific dietary restrictions or preferences, or if you have medical reasons to take vitamin D2, your healthcare provider may recommend vitamin D2 supplements.

8- Vitamin D2 and feeding tubes

For patients who require tube feeding or parenteral nutrition, ergocalciferol capsules contain D2 in oil, can clog the feeding tube and therefore should not be used.

Cholecalciferol capsules and tablets contain D3 in powder form can be used without clogging the feeding tube.

Patients with malabsorption often require larger maintenance dosing of vitamin D.

9- What is the best time to take vitamin D?

Vitamin D is a fat-soluble vitamin so it’s best absorbed when taken with or after a meal and not on an empty stomach.

10- If I have vitamin D deficiency, should I take calcium supplement?

It’s important to ensure adequate oral intake 500 to 600 mg of calcium, but not necessary by supplementation.

11- Should I take vitamin k2 with vitamin D?

Vitamin K2 helps guide calcium into the bones and teeth, where it's needed, and prevents it from accumulating in undesirable places. Taking both vitamins together ensures that calcium is properly utilized in the body. Without vitamin K2, calcium can be deposited in soft tissues like arteries and joints, potentially leading to health issues.

The dosage of vitamin K is approximately 1 microgram of each kg of body weight for adults.

It is also important to highlight that Vitamin D supplement form may interact with several types of medications such as Orlistat, Statins, Steroids, Thiazide diuretics. Before starting any new supplement regimen, it's crucial to consult with a healthcare professional, as individual needs can vary. Self-supplementation without proper guidance can lead to imbalances and potential health risks.

If you need nutrition assessment for your intake, don’t hesitate to contact us.

Use the below references to read more about this topic:

Anouti, F. A., Ahmed, L. A., Riaz, A., Grant, W. B., Shah, N., Ali, R., Alkaabi, J., & Shah, S. M. (2022, March 3). Vitamin D Deficiency and Its Associated Factors among Female Migrants in the United Arab Emirates. Nutrients, 14(5), 1074.

Kennel, K. A., Drake, M. T., & Hurley, D. L. (2010, August). Vitamin D Deficiency in Adults: When to Test and How to Treat. Mayo Clinic Proceedings, 85(8), 752–758.

Office of Dietary Supplements - Vitamin D. (2022, August 12). Vitamin D - Health Professional Fact Sheet.




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