Winter Wellness Focus: Vitamin D and Your Health

Why Vitamin D Matters More in Winter

During the winter months, shorter days and weaker sunlight make it difficult for your body to produce enough vitamin D from sun exposure alone. Vitamin D plays an important role in bone strength, muscle function, calcium absorption, and immune health. People who live at higher latitudes, spend most of their time indoors, or wear more skin-covering clothing in cold weather are especially likely to experience low vitamin D levels in winter. For many individuals, dietary sources alone are not enough, which is why supplementation is commonly recommended when sunlight is limited.

What the Research Shows

Research has shown that vitamin D supplementation during winter is effective at maintaining healthy levels of the vitamin in the blood and preventing the seasonal dip that occurs with reduced sun exposure. In a randomized controlled trial published in 2023, daily supplementation with 1,000 IU of vitamin D₃ during the winter months significantly increased blood 25-hydroxyvitamin D levels compared with placebo, demonstrating that supplementation successfully counteracts the winter decline in vitamin D status (Shab-Bidar et al., 2023, Nutrients). Adequate vitamin D status supports immune function and may influence musculoskeletal health by helping regulate calcium and bone metabolism.

Recommended Supplementation

For most healthy adults, typical preventive supplementation ranges from 600–800 IU (15–20 mcg) daily, with many clinicians recommending 1,000–2,000 IU daily in winter for people at higher risk of deficiency.

• Infants: 400 IU daily

• Children and teens: 600–1,000 IU daily depending on diet and sun exposure

Because vitamin D is fat-soluble, taking very high doses for long periods without supervision is not recommended; more than 4,000 IU daily should only be taken under medical guidance. A simple blood test can check your vitamin D level and help us choose the right dose for your individual needs.