There are five forms of vitamin D: D1, D2, D3, D4 and D5. Vitamin D2, ergocalciferol and Vitamin D3, cholecalciferol are the most important to consider.  Vitamin D2 is produced in fungus, invertebrates and plants in response to sunlight.  Humans produce vitamin D3 in response to sunlight.  At least 10 to 15 minutes of over 3-UV sun exposure, at least 2 times a week is required to produce adequate amount of vitamin D3.

Vitamin D plays many essential roles in the body: it is needed for the absorption and use of calcium and phosphorous; it regulates the immune system; it may play a role in preventing cognitive decline as we age; it reduces asthma symptoms and the risk of rheumatoid arthritis; it protects us from radiation and cancer.

Vitamin D deficiency has been linked to:

  • · Alzheimer’s disease
  • · Bacterial vaginosis
  • · Cancer
  • · Chronic pain
  • · Cognitive impairment
  • · Heart disease
  • · High blood pressure
  • · Inflammation
  • · Multiple sclerosis
  • · Osteomalcia
  • · Osteoporosis
  • · Parkinson’s disease
  • · Periodontal disease
  • · Peripheral artery disease
  • · Rickets
  • · Seasonal Affective Disorder
  • · Tuberculosis

Both modern diet and lifestyle contribute to vitamin D deficiencies.  We spend much less time outdoors than we once did and much of the natural vitamin D in our foods is degraded by processing.

Foods fortified with vitamin D haven’t proven as helpful as natural sources and even with such supplements, vitamin D deficiencies have increased significantly over past decades.  The current USDA upper limits and recommendations for vitamin D intake are currently under review and will likely be raised tremendously.

University of Minnesota researchers have found that vitamin D levels affect weight loss: high levels of vitamin D are associated with increased weight loss success.