Vitamin D

Vitamin D is a particularly important nutrient in northern climates, where sunlight is insufficient during winter months for vitamin formation in the skin. Studies show that up to 40% of people suffer from vitamin D deficiency during winter.

Vitamin D regulates calcium absorption and is therefore essential for bone health. This is especially important for women, as osteoporosis risk increases after menopause. Additionally, vitamin D affects immune system function, muscle function, and mood.

Studies have shown a connection between vitamin D deficiency and weight gain. Adequate vitamin D levels support metabolism, insulin sensitivity, and may promote fat burning. Deficiency, on the other hand, has been linked to fatigue, which reduces movement and NEAT expenditure.

The recommended daily intake for adults is 10 micrograms, but many experts recommend a higher dose (20-50 micrograms), especially during winter. Good food sources include fish, fortified dairy products, and egg yolk. A vitamin D supplement is recommended from October through March.

Last updated: March 30, 2026