Professor Hollis is the scientist who provided the best reason to keep your vitamin D level around 50 ng/ml. Some scientists say 20 ng/ml is good enough because parathyroid hormone (PTH) is pretty much suppressed with levels of 20, other scientists say levels should be 30 because calcium absorption is maximized with that level. That is, PTH suppression and calcium absorption are biomarkers for adequate vitamin D blood levels.
Professor Hollis provided another biomarker, one every woman – and most men – can immediately accept as the best biomarker yet: how much vitamin D does a woman need to be sure that her breast milk has adequate vitamin D? When you think about it, that’s about as good as biomarkers get.
Professor Hollis answered that question in his research, finding that when a lactating woman has vitamin D blood levels of 40-50 ng/ml, her breast milk finally has enough vitamin D to support the vitamin D levels of her nursing infant. At levels below 40, the vitamin D content of breast milk becomes unpredictable. Human breast milk – unlike the breast milk of wild mammals – has little or no vitamin D. Nature’s most perfect food is too often void of the pre-hormone needed for infant growth and development.
Dr. Bruce found that breast milk is not void of it, it is just that virtually all modern lactating women are void of it.
There is a 25-hydroxyvitamin D test, also called a 25(OH)D. Levels should be above 50 ng/ml (125 nmol/L) year-round, in both children and adults. Thanks to Bruce Hollis, Robert Heaney, Neil Binkley, and others, we now know the minimal acceptable level. It is 50 ng/ml (125 nmol/L). In a recent study, Heaney, et al expanded on Bruce Hollis’s seminal work by analyzing five studies in which both the parent compound (cholecalciferol) and 25(OH)D levels were measured. They found that the body does not reliably begin storing cholecalciferol in fat and muscle tissue until 25(OH)D levels get above 50 ng/ml (125 nmol/L). The average person starts to store cholecalciferol at 40 ng/ml (100 nmol/L), but at 50 ng/ml (125 nmol/L) virtually everyone begins to store it for future use.
At levels below 50 ng/ml (125 nmol/L), the body uses up vitamin D as fast as you can make it, or take it, indicating chronic substrate starvation—not a good thing. 25(OH)D levels should be between 50–80 ng/ml (125–200 nmol/L), year-round.
Two forms of Vitamin D are important in humans: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D2 is synthesized by plants. Vitamin D3 is synthesized by humans in the skin when it is exposed to ultraviolet-B (UVB) rays from sunlight. Foods may be fortified with vitamin D2 or D3.Vitamin
Other ways Vitamin D is needed in the body
- maintains normal blood levels of calcium and phosphorus.
- aids in the absorption of calcium, helping to form and maintain strong bones.
- protection from osteoporosis, hypertension (high blood pressure), cancer, and several autoimmune diseases.
- calcium absorption which your bones need to grow.
- needed for nerve, muscle, and immune systems function.
Excerpts courtesy of John Cannell, MD/Vitamin D Council http://bit.ly/kAGVcX
Excerpts courtesy of http://bit.ly/kcNiCV
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