More Isn't Always Better

 

Vitamin D is a key nutrient. You need it in order to absorb calcium and you need it for bone growth, density and strength. It also helps build muscle and fight inflammation. Along with magnesium it is helpful in countering hypertension and has many other well documented benefits. But Vitamin D, along with Vitamins A, E and K, is fat soluble. Unlike water soluble vitamins like C and B, with fat soluble vitamins amounts beyond what your body requires are not simply excreted in the urine but accumulate in fat tissue and in the liver. In high enough amounts they can be toxic.

In a study 2019 study published in JAMA, researchers randomly assigned over 300 people over age 55 to take one of three daily doses of Vitamin D: 400UI, 4,000IU or 10,000IU. All participants had low blood levels of Vitamin D at the start of the study but none were classified as "deficient". After three weeks, bone density was lower in the groups taking the higher doses compared to the 400IU group. Bone strength was no different among the three groups.

So not only are high doses risky, but they do not appear to confer any advantage over the recommended dose of 600IU (800IU for those over 70 years old). At least not for bone health.

Then there is the cautionary tale of Gary Null. Null, who sold Gary Null's Ultimate Power Meal, and six of his customers were hospitalized after taking a batch of product that had accidentally been produced containing 1,000 times the intended dose of Vitamin D.

Despite what you may read, be cautious taking meagdoses of anything. Do your research. In particular, research the research. Who funded the study? Was it conducted in a valid way? Did the results really say what is being reported? Don't let yourself be Null-ified.