Most Heart Scan Blog readers already know:
Your doctor has been brainwashed by the pharmaceutical industry.
Your doctor more than likely has spent the better part of his or her career in the Guantanamo Bay of healthcare, water-boarded by seductive sales representatives, enticed with promises of fame and riches, threatened with ostracism from the clubby internal halls of healthcare if--gasp!--he or she didn't subscribe to the "rule�" that only drugs are good, anything else is bad.
The same FDA-approval-is-necessary-to-be-good brand of nonsense is gaining popularity among my colleagues who, having caught some mention (on the Today Show, Oprah, or similar source of medical information), hope to join the vitamin D hoopla.
People will proudly declare that they are taking a high dose of vitamin D: 50,000 units once per week.
No. They are taking a barely useful form: D2, ergocalciferol.
Studies examining the reliability of the D2 form differ:
There's the Heaney study suggesting that D2 is less effective than D3:
Vitamin D2 is much less effective than vitamin D3 in humans
Then there's the Holick study showing they are equivalent:
Vitamin D2 is as effective as vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D.
My experience is more in line with the Heaney study: Little or no real effect with D2.
One particularly illustrative case I witnessed was a woman who was mistakenly prescribed D2 at 50,000 units per day . She told me that she'd been taking it for a year. I fully expected to see clear-cut signs of toxicity (e.g., high blood calcium levels). Curiously, she showed no signs of toxicity. Nor did she show any vitamin D at all in her blood: 25-hydroxy D level of zero--literally zero.
I've witnessed similar phenomena several times: plenty of vitamin D2 . . . very little vitamin D in the blood.
All in all, I suppose that D2 is better than No-D at all. But you are far better off joining the ranks of the pharmaceutically challenged and go with the stuff that really works: D3.
D3, or cholecalciferol, yields confident increases in blood levels. It is inexpensive, safe, and an exact copy of the human form of vitamin D. (Of course, gelcap or drops only , NEVER tablets.)
There is absolute NO reason to take vitamin D2, the form that sometimes works, sometimes doesn't, the facsimile plant form issued by the drug industry.