What is Vitamin D?

Vitamin D is both a nutrient we eat and a hormone our bodies make. It helps the body absorb calcium and phosphorus, which are essential for building and maintaining strong bones and teeth. Beyond bone health, vitamin D supports immune function, helps regulate inflammation, and may play roles in muscle strength, mood, and chronic disease prevention.

Your body can make vitamin D when your skin is exposed to sunlight. However, factors such as season, time of day, age, skin pigmentation, sunscreen use, and limited outdoor time can reduce how much your body produces. Because of this, many people, especially those in Canada, need to rely on food and supplements to get enough.

Why Vitamin D Matters

Vitamin D deficiency can lead to serious health concerns. In children, it causes rickets, a condition that weakens bones and leads to deformities. In adults, low vitamin D can cause osteomalacia (soft bones) and contribute to osteoporosis.

On the other hand, getting enough vitamin D supports bone strength, reduces fracture risk, and contributes to overall well-being. There is ongoing research into its role in reducing risks of cancer, cardiovascular disease, type 2 diabetes, infections, and cognitive decline.

How Much Vitamin D Do You Need?

Health Canada and the U.S. Institute of Medicine recommend the following daily amounts:

• Children & Adults 9–70 years: 600 IU (15 µg)

• Adults over 70 years: 800 IU (20 µg)

• Infants and young children: 400–600 IU depending on age

The Tolerable Upper Intake Level (UL) — the maximum daily amount unlikely to cause harm — is 4,000 IU (100 µg) for people 9 years and older.

Health Canada allows non-prescription supplements up to 2,500 IU (62.5 µg) per day for children 9+ and adults. Higher doses may be prescribed when medically necessary, but should not be taken without professional supervision.

Food Sources of Vitamin D

Few foods naturally contain vitamin D. Most dietary vitamin D comes from fortified foods. Sources include:

• Fatty fish (salmon, trout, arctic char, sardines)

• Egg yolks

• Fortified milk and plant-based beverages

• Soft margarine

• Fortified cereals

• Cod liver oil

If you don’t consume vitamin D rich foods every day, a supplement of at least 400 IU is recommended.

Sunlight and Vitamin D

Sun exposure is a natural way to produce vitamin D, but effectiveness depends on:

• Smog or cloud cover

• Season and latitude (little to no production in Canadian winters)

• Sunscreen use (blocks over 90% of production)

• Skin tone (more melanin = slower vitamin D production)

• Age (older adults make less)

Because excessive UV exposure increases skin cancer risk, supplements and fortified foods are the safest and most reliable way to maintain healthy vitamin D levels.

Signs of Deficiency and Toxicity

Deficiency may cause:

• Bone pain, muscle weakness

• Rickets in children

• Osteomalacia in adults

• Toxicity is rare and usually only from excessive supplement use. Symptoms include:

• Loss of appetite, weight loss

• Irregular heartbeat

• Kidney and heart damage due to calcium buildup

Daily supplementation above 4,000 IU is not recommended unless prescribed and monitored by a healthcare provider.

Vitamin D at Wellcare College Pharmacy

Vitamin D is an essential nutrient for everyone, whether you’re a child, adult, or senior. Because Canadian winters limit sunlight exposure, supplements are a safe and effective way to ensure you’re meeting daily needs.

Our pharmacists can help you choose the right vitamin D supplement for your age, diet, and health condition. We carry a range of options, including vitamin D3 capsules, drops, and combination products with calcium for bone support.

Speak with one of our pharmacists today to find the vitamin D option that’s best for you.