Fall and winter bring shorter daylight hours and less exposure to natural sunlight for most Wisconsinites. Sunlight is our greatest source of Vitamin D! We need an average of at least 15-20 minutes of sun exposure to the face, arms, hands, and legs without sunscreen several days per week, particularly between 10 a.m. and 4 p.m., in order to maintain adequate levels from sun. Vitamin D is most important for maintaining strong bone health.

Breastfed infants, older adults, those with very limited sun exposure, people with darker pigmented skin, folks with fat malabsorption risk in the gut (some forms of liver disease, cystic fibrosis, celiac disease, Crohn’s disease, and ulcerative colitis), patients with chronic kidney disease and those with obesity or prior history of gastric bypass surgery are all at risk for Vitamin D deficiency.

You might consider adding daily OTC Vitamin D3 to meet the recommended daily allowances – at least fall through spring. It is available in several oral forms, including gummies (our family’s favorite!). Some foods are natural sources for Vitamin D, however, levels are typically very low making it difficult to get enough from dietary sources alone. Many health professionals feel we may actually need supplement levels slightly higher than the RDA levels noted below – adults might need at least 37.5 to 50 mcg (1,500–2,000 IU)/day of supplemental vitamin D, and children and adolescents might need at least 25 mcg (1,000 IU)/day.

However, because it’s a fat soluble vitamin, it can accumulate and have toxic effects, namely pushing blood calcium levels too high. Please consult with your physician if taking supplement levels above 4000IU daily for adults, or above 1000IU for infants and children!

Tables below are taken from this comprehensive Vitamin D review by the National Institutes for Health (NIH).