Vitamin D Guide

Vitamin D helps build and maintain strong bones and teeth, supports immune function, and helps the body absorb calcium and phosphorus.¹

✅ Reviewed by Jamieson's Science Team

Quick Answers

What is vitamin D?

A fat-soluble vitamin that can come from food, supplements, and production in the skin after sunlight exposure.³

What does vitamin D support?

Strong bones and teeth, calcium absorption, and immune function.¹

Where is vitamin D found?

Sources include fatty fish, egg yolks, fortified foods, and supplements.³

Are vitamin D and vitamin D3 the same?

Vitamin D3 is one of the two main supplemental forms of vitamin D.³

What is vitamin D?

Vitamin D is a fat-soluble vitamin that supports several important functions in the body. It is naturally present in a limited number of foods, added to some fortified foods, and available in supplements. Your body can also make vitamin D when skin is exposed to sunlight.³ 

Vitamin D is especially important for helping the body absorb calcium and phosphorus, two minerals needed to build and maintain bones and teeth.¹ 

How does your body use vitamin D?

Vitamin D from food, supplements, and the skin is processed by the liver and kidneys before the body can use it. Its active form helps the intestines absorb calcium and phosphorus and supports the processes that maintain bones and teeth.¹˒³ 

Vitamin D also contributes to normal immune function by supporting cells involved in the body’s immune response.¹˒³ 

Which health goals can vitamin D support?

Immune Support

Vitamin D helps maintain immune function and supports cells involved in the body’s natural immune response.¹˒³

Bone Health

Vitamin D helps the body absorb and use calcium and phosphorus. Along with sufficient calcium, a healthy diet, and regular exercise, it supports the development and maintenance of strong bones and teeth.¹

Children’s Health

Vitamin D helps children build and maintain strong bones and teeth. Needs and appropriate supplement formats vary by age.¹˒²

Everyday Wellness

Vitamin D supports calcium and phosphorus absorption, bone health, and immune function, making it an important part of maintaining overall health.¹

How can you support your vitamin D intake?

Vitamin D can come from food, supplements, and production in the skin. 

  • Include food sources: Fatty fish, egg yolks, and fortified foods such as milk and some plant-based beverages can provide vitamin D.³ 
  • Check fortified-food labels: The amount of vitamin D can vary between products. 
  • Practise sun safety: The skin can make vitamin D after sunlight exposure, but production varies and sun protection remains important.³ 
  • Check for overlap: Multivitamins, calcium products, and immune-support formulas may already contain vitamin D. 
  • Follow supplement directions: Choose an amount and format appropriate for the person’s age and life stage. 

*It is important to consult your trusted healthcare practitioner before adding any new natural health supplement to your routine. 

What should you look for in a vitamin D supplement?

Start with what you need, then choose a product that fits your life.

  • Know who it’s for: Needs vary by age and life stage. 
  • Check the amount: 1 mcg of vitamin D equals 40 IU.² 
  • Choose the strength: Follow the product directions. 
  • Find your format: Choose tablets, gummies, softgels, or drops. 
  • Check for overlap: Review other supplements for vitamin D. 
  • Look for quality: Choose a licensed product with an eight-digit NPN. 

For more than 100 years, Jamieson has combined scientific expertise with rigorous quality testing. Every product is backed by the Jamieson 360 Quality Promise. 

*It is important to consult your trusted healthcare practitioner before adding any new natural health supplement to your routine.  

Explore Vitamine D
31000444 Jamieson Vitamin D3 Chewables 1,000 IU Tablet 31000444_MAIN
-15%
Vitamine D3 | À Croquer
$10.19
$11.99
2200 2200_MAIN
-15%
Vitamine D3
À partir de $9.34
$10.99
31000859 Jamieson Vitamin K2 & Vitamin D3 30 Softgels 9043_MAIN
Épuisé
Vitamine K2 & Vitamine D3
À partir de $17.99
9658 9658_MAIN
Vitamine D3 2,500 UI
$16.99
5869 5869_MAIN
Vitamine D3 pour les enfants
$9.99
9645 9645_MAIN
Épuisé
Vitamine D. 2 500 | Gummies
$17.99
7961 7961_MAIN
Mega Cal | Calcium et vitamine D3
À partir de $27.99
9753 9753_MAIN
Épuisé
Vitamine D3 2 500 UI | À croquer
$13.99
View all Products

FAQs
How much vitamin D do adults need each day?

Health Canada’s dietary reference intakes recommend 600 IU, or 15 mcg, per day for adults aged 19–70. The recommendation increases to 800 IU, or 20 mcg, after age 70.²

How much vitamin D do infants need?

The adequate intake for infants from birth to 12 months is 400 IU, or 10 mcg, per day.² Parents and caregivers should use a product designed for infants and follow its directions carefully.

What is the difference between vitamin D2 and vitamin D3?

Vitamin D2 and vitamin D3 are both forms of vitamin D. Vitamin D2 is called ergocalciferol, while vitamin D3 is called cholecalciferol. Both can increase vitamin D levels, although their sources and effects may differ.³

Sources
  1. Health Canada. Multi-Vitamin/Mineral Supplements Monograph. Natural and Non-prescription Health Products Directorate. Updated March 5, 2026.[Text Wrapping Break] https://webprod.hc-sc.gc.ca/nhpid-bdipsn/atReq?atid=multi_vitmin_suppl&lang=eng 
  2. Health Canada. Dietary Reference Intakes Tables: Reference Values for Vitamins.[Text Wrapping Break]https://www.canada.ca/en/health-canada/services/food-nutrition/healthy-eating/dietary-reference-intakes/tables/reference-values-vitamins.html 
  3. National Institutes of Health, Office of Dietary Supplements. Vitamin D: Fact Sheet for Health Professionals.[Text Wrapping Break] https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/