Can You Take Too Much Vitamin D?
Vitamin D intake has many proven health benefits. It’s great for increasing immune health, reducing your risk of heart disease, and even plays a role in normal growth and development of bones and teeth.
The Importance of Vitamin D Supplementation:
Your body produces Vitamin D in response to sunlight, which gives this vitamin the nickname “The Sunshine Vitamin.” It’s found in small concentrations in foods like egg yolks, salmon, and fortified cereals and milks, but many people have to supplement to get the right amount of this essential vitamin.
Some symptoms of vitamin D deficiency include fatigue, aches & pains, bone or muscle pain, and in the worst cases, even stress fractures.
Doctors can diagnose a vitamin D deficiency by performing a simple blood test. If you have a deficiency, your doctor may order X-rays to check the strength of your bones.
To avoid deficiency, it’s important to increase your intake. But is there such a thing as too much vitamin D?
Signs You’re Taking Too Much Vitamin D:
Some signs of too much Vitamin d include dehydration, lethargy, and nausea.
Vitamin D “toxicity” is actually measured by serum calcium levels or by urine levels of calcium. The easiest way to measure urine calcium is by taking a random morning urine sample and checking the ratio of calcium to creatinine.
Assuming one does not have renal insufficiency, hypercalciuria (too much calcium spilling into urine) is rated at calcium/creatinine of > 1mmol/mmol or > 0.37mg/mg.
So, if you are having symptoms from too much vitamin D intake, your symptoms are actually caused by hypercalcemia (too much calcium in the blood.) These symptoms – nausea, lethargy, and dehydration – can point to a number of medical conditions, so it’s difficult to know if these symptoms are associated with too much vitamin D intake.
If you believe you are taking too much vitamin D, then check your serum and urine calcium levels to find a true answer.
How Difficult Is It To Take Too Much Vitamin D?
The NIH uses one particular study to set what they call the safe level of Vitamin D intake; this study showed a statistically significant increase in calcium when people took 2000iu daily.
Since then, a study with more patients taking Vitamin D for longer time periods demonstrated no increase in serum or urine calcium when taking 4000iu daily. Another study showed a dose of 50,000iu daily was also noncalcemic. The amount of supplementation set at 4000iu or so mimics what would be achieved with adequate sunlight exposure.
Vitamin D only becomes toxic if it saturates its binding protein. Vitamin D only saturates normal binding capacity of the D-binding-protein (DBP) if it reaches 20-times the physiologic total concentration of the ligands; this is the safe range.
Most evidence would support that taking 10,000iu daily would not pose a risk in almost all people, meaning that it would be very difficult to take too much to have vitamin D toxicity Should one have concerns, obviously one should discuss this with a personal physician or wellness team.