Vitamin D: Why It Matters, Especially in Winter

Vitamin D plays an important role in maintaining good health, especially for strong bones and teeth. It helps your body absorb calcium, supports normal muscle function and contributes to a healthy immune system. Getting enough Vitamin D is especially important for maintaining bone health and reducing the risk of conditions such as osteoporosis.

Why Is Vitamin D a Concern for Canadians?

Your body naturally produces Vitamin D when your skin is exposed to sunlight. However, getting enough from sunlight can be challenging, particularly during the fall and winter months, even in our southern Windsor-Essex. Shorter days, colder temperatures, cloud cover and heavy winter clothing all limit our exposure.

Fortunately, you can help maintain adequate Vitamin D levels through everyday food choices and, when appropriate, supplements.

Foods That Contain Vitamin D

Although relatively few foods naturally contain Vitamin D, several good options can be incorporated into your diet:

• Egg yolks: A natural source of Vitamin D.

• Fatty fish: Salmon, tuna, trout and other oily fish.

• Fortified milk: Cow's milk is an important dietary source.

• Fortified plant-based beverages: Such as fortified soy, almond and oat beverages.

• Fortified foods: Some cereals, orange juices and other products contain added Vitamin D.

• Certain mushrooms exposed to ultraviolet light can also provide Vitamin D.

When shopping, check nutrition labels to see how much Vitamin D a product contains. It's worth noting that Canadian food fortification requirements changed in January 2026, increasing the amount of Vitamin D in milk and other products.

How Much Vitamin D Do You Need?

Health Canada's dietary reference recommendations vary by age:

• Children and adults aged 9–70: 600 IU (15 mcg) per day.

• Adults over 70: 800 IU (20 mcg) per day.

Health Canada also recommends a daily Vitamin D supplement of 400 IU (10 mcg) for adults aged 51 and older. For adults aged 18 to 50, a daily dietary source of Vitamin D is recommended, either through food or a 400 IU supplement if they don't regularly consume Vitamin D-containing foods.

Individual requirements can vary depending on age, diet, health conditions and other factors. Your healthcare provider can help determine whether supplementation is appropriate.

Can You Get Too Much Vitamin D?

While Vitamin D is essential, more isn't necessarily better. Taking excessive amounts of Vitamin D supplements over time can lead to a buildup of calcium in the blood (hypercalcemia). This can contribute to kidney damage, kidney stones and calcium deposits in soft tissues, including blood vessels and other organs.

For most adults, the established tolerable upper intake level is 4,000 IU per day from all sources. This is a safety limit, not a recommended daily target.

Avoid taking high-dose supplements unless advised by a healthcare professional.

Take Steps to Support Your Health

Maintaining adequate Vitamin D levels is one part of looking after your overall health and supporting strong bones. A balanced diet, appropriate supplementation and regular physical activity all contribute to long-term well-being.

If you're concerned about your Vitamin D intake or whether you may need a supplement, speak with your family doctor. They can help you determine what's appropriate for your individual needs.