Vitamin D3 is the only vitamin the body can manufacture from sunlight (UVB). Yet, with today’s indoor living and the extensive use of sunscreens due to concern about skin cancer, we are now a society with millions of individuals deficient in life-sustaining bone building and immune modulating 1,25-dihydroxy Vitamin D3.
Supplemental vitamin D comes in two forms:
- Ergocalciferol (vitamin D2)
- Cholecalciferol (vitamin D3)
For more than a century, scientists have recognized that Vitamin D3 is involved in bone health. Research has continued to accumulate, documenting Calcitriol’s (is the hormonally active form of vitamin D) role in the reduction of the risk of fractures to a significant degree. The latest research, however, shows that 1,25-dihyroxy Vitamin D3 deficiency is linked to a surprising number of other health conditions such as depression, back pain, cancer, both insulin resistance and pre-eclampsia during pregnancy, impaired immunity, macular degeneration, bone health.
As it becomes clear that Vitamin D3 plays a wide role in overall health, it’s becoming equally clear that a large percentage of individuals are deficient in this important nutrient, which has hormone-like activity. The fear of skin cancer has stopped many individuals from obtaining beneficial amounts of sunlight. The skin uses the energy of UVB to convert 7-dehydrocholesterol into Vitamin D3. Even individuals, who venture out into the sun often and use suntan lotion, may be deficient in Vitamin D3. Furthermore, as we age, we are less equipped to produce sufficient quantities of this vital nutrient. One study found that age-related declines in kidney function may require older people to ingest more Vitamin D3 to maintain the same blood levels as younger people.
The Recommended Daily Intake (RDI) of Vitamin D3 is set so low those mature individuals who consume this small amount (400 to 600 International Unites (I.U.’s)) are still likely to be deficient if they live north of the Tropic of Cancer or south of the Tropic of Capricorn. In fact, researchers have discovered that the RDI, which was considered adequate to prevent osteomalacia (a painful bone disease) or rickets, is not high enough to protect against the majority of diseases linked to 1,25-dihyroxy Vitamin D3 deficiency. For example, an analysis of the medical literature found that at least 1,000 to 2,000 IU of Vitamin D3 per day is necessary to reduce the risk of colorectal cancer and that lower doses of Vitamin D3 did not have the same protective effect.
Researchers, led by Dr. Amie L. Peterson from the Oregon Health and Sciences University, conducted a cross-sectional analysis of 286 patients with Parkinson's disease. They found that higher 25-hydroxyvitamin D (vitamin D3) blood levels were associated with less severe symptoms of Parkinson's, better cognition, and less depression in all the patients studied. Adding to this, patients who didn't suffer with dementia had the highest vitamin D3 blood levels.
Dr. Peterson explained that nearly 30 per cent of patients suffering with Parkinson's disease also suffer from cognitive impairment and dementia. However, a study conducted in 2012, published in The Journals of Gerontology, found that women with a low vitamin D intake were more likely to encounter cognitive decline. This adds to the evidence of another study, which had similar results and found that women who developed Alzheimer's disease (a severe form of dementia) had lower vitamin D levels than those who did not develop the illness.
One of the challenges is the outdated acceptable upper limit for Vitamin D3 consumption, which was set at 2,000 IU. However, researchers point out that more recent studies have shown that 8,000 to 10,000 IU is the safe upper limit.
Dr. R. Vieth, one of the foremost authorities on Vitamin D3 supplementation, has extensively studied Vitamin D, and lamented the low requirements for Vitamin D3 in a recent issue of the Journal of Nutrition: “Inappropriately low UL [upper limit] values, or guidance values, for Vitamin D have hindered objective clinical research on Vitamin D nutrition; they have hindered our understanding of its role in disease prevention, and restricted the amount of Vitamin D in multivitamins and foods to doses (that are) too low to benefit public health.”
A growing number of researchers who have widely studied Vitamin D3 are almost begging the general public to consume more of this important nutrient. Due to Vitamin D3’s high safety profile in doses up to 10,000 IU per day and because of the wide role it plays in our health, consuming 2,000 to 5,000 IU per day of this nutrient at times of the year when sunlight is scarce is a prudent way to improve overall health.