Vitamin D: from too low to overdose

Vitamin D research is revving up across the globe, and the latest findings link low blood levels to a serious complication of early pregnancy: early-onset severe preeclampsia.  Eclampsia, characterized by high blood pressure and elevated protein in urine, is a serious problem that occurs after the 20th week of pregnancy.  Risk factors include a variety of chronic conditions like diabetes, obesity, kidney disease and older age.  A specific cause has not been identified, although poor diet is one suspect.  Now researchers have linked this particularly severe form of eclampsia to low blood levels of vitamin D.  The average level for those pregnant women with eclampsia was 18 nano grams per milliliter, compared to an average level of 32 for healthy subjects.  This difference was statistically highly significant, despite the fact that some vitamin D experts believe the optimal blood level for vitamin D is 50 ng/ml.

This study didn’t examine a possible mechanism for vitamin D affecting a pregnant woman’s risk for developing eclampsia, and the authors noted that more research is needed.  There is evidence that vitamin D affects blood pressure in general, so a link to this acute and severe form of hypertension in pregnancy wouldn’t be surprising.  Pregnant women should have their vitamin D levels checked before starting any supplements, since the role of this vitamin for multiple health outcomes is critical.

Key message: “before starting supplements”.  Public television’s perpetually tan health guru* Gary Null recently overdosed on vitamin D while consuming his own “Gary Null’s Ultimate Power Meal”.  While the label said the power meal contained 2000 i.u., in fact it contained 2,000,000 i.u.  Even vitamin D proponents would consider that way too much.  The result was that Mr. Null developed a host of symptoms from excess vitamin D, including extreme fatigue and pain.  Unfortunately his initial response to his symptoms was to consume more of the Power Meal, thinking it would have magical healing powers for whatever ailed him.  Oops.  Vitamin D is a fat soluble vitamin, meaning excess will not be flushed out by the kidneys.  Once it’s absorbed, it stays in your blood until it’s used up.  That can take a very long time, depending on the level.  Mr. Null’s levels were not reported – it sure would be fascinating to know what they were.

Take-away message #1: don’t take vitamin D until you’ve had your blood level tested.  If you’re low, appropriate supplements can be recommended based on test results.

Take-away message #2: There is no regulation of supplement manufacturing in the US.  The contents of supplements, powders, meals replacements, drinks and the like are not monitored.  Some organizations, like Consumer Labs, regularly test products for content and contaminants, but this is not a government agency.

*NOTE: being called a guru does not mean Gary Null is an expert.

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