Vitamin D Supplementation Timing for Autumn and Winter: Expert Guidance
Approximately 35% of individuals in the U.S. experience suboptimal vitamin D levels, making it wise to consider supplementation as the autumn and winter months diminish UVB exposure. According to naturopathic nutritionist Jessica Shand, many people struggle to synthesize sufficient vitamin D through their skin during this time. Low vitamin D levels can negatively impact immune health, bone strength, and mood, with a study from the National Health Institute linking them to feelings of low mood. Dr. Kaywaan Khan notes that reduced light exposure leads to seasonal affective disorder (SAD). Clinical nutritionist Lucy Miller recommends a daily intake of 10 micrograms (400 IU) during fall and winter, particularly for those with darker skin or limited sunlight, and suggests consulting a doctor to check levels and starting supplementation in September or October.
Key facts
- About 35% of people in the United States have below-optimal vitamin D levels
- Jessica Shand is a naturopathic nutritionist and author of The Hormone Balance Handbook
- A National Health Institute study links insufficient vitamin D to low mood
- Kaywaan Khan, MD, previously explained SAD to Vogue as depression caused by reduced light exposure
- Clinical nutritionist Lucy Miller cites NHS advice of a 10 microgram (400 IU) daily supplement during fall and winter
- Melanin reduces vitamin D synthesis, so people with darker skin tones may consider year-round supplementation
- Vitamin D receptors are found in reproductive tissues and have been studied in relation to ovarian function, fertility, insulin sensitivity, and PMOS
- Miller recommends starting in September or October and continuing through early March if summer sun exposure was adequate
- Miller recommends the D3 form alongside K2 and magnesium glycinate for absorption
- Private testing is available from providers such as Function Health
Entities
Artists
- Jessica Shand
- Kaywaan Khan
- Lucy Miller
Institutions
- Vogue
- National Health Institute
- NHS
- Function Health
Locations
- United States