What’s the biggest problem with calcium? It may come as a surprise that while most people don’t have a problem getting enough calcium, there is a major problem for many people when it comes to keeping calcium in their body so that it can help strengthen bone.
In fact, 20% or more of people with osteoporosis suffer from hypercalciuria — excessive loss of calcium in the urine. No matter what the cause, hypercalciuria always jeopardizes bone and is associated with lower bone density and increased fracture risk.
The link between hypercalciuria and osteoporosis is so strong that expert researchers suggest everyone with a diagnosis of osteoporosis be screened for it.
Do you have hypercalciuria?
Luckily, there’s a fairly simple laboratory test to determine if you’re losing calcium. You’re asked to collect your urine over 24 hours and submit it for chemical analysis to determine how much calcium it contains. Most labs consider any 24-hour calcium loss over 250–300 mg of calcium to be excessive.
- If your 24-hour urine calcium comes back high, don’t panic: You may have gotten that result simply because you are taking too much calcium. When there’s an unusually high consumption of calcium from diet and supplements, the body simply moves unneeded calcium from the body into urine to get rid of it. Your doctor will likely recommend you retake the test, but this time avoiding all calcium supplements (and probably also dairy foods) for a week before again collecting your 24-hour urine sample.
- If your re-test shows you’re genuinely losing calcium, again: don’t panic. Excessive calcium loss in the urine can be due to factors like high intake of salt, caffeine, soda, or sugar, low levels of nutrients like magnesium, vitamin D, and vitamin K, and even prolonged stress. These factors all promote an acidic pH (which promotes calcium loss), and they’re all things you can begin correcting on your own.
Dietary and lifestyle changes may not always solve the problem (though they may), as loss of calcium can also be related to medical issues such as hyperparathyroidism, kidney issues, hyper-absorption of calcium, vitamin D toxicity, autoimmune sarcoidosis or excessive bone breakdown related to “silent” diseases like diabetes or thyroid disorders. If your calcium excretion is consistently high, such possible causes should be explored by your physician.
What are your options if you have hypercalciuria?
If testing confirms you’re losing excessive calcium but your healthcare practitioner can’t identify and correct the cause of this problem, it’s pretty common practice to recommend a thiazide diuretic, which is known to help keep calcium in the body.
I favor the approach used by functional medicine and naturopathic practitioners, which is to first try to reduce urine calcium loss with a program of lifestyle and nutritional changes, perhaps combined with acupuncture to enhance kidney functioning, before using medications. But no matter what therapeutic approach you choose, it’s always important to retest and make sure that you have effectively reduced the loss of calcium in the urine.
Keep in mind that a high loss of calcium in the urine not only weakens bone, but also puts you at risk of developing kidney stones. Thus, if you are experiencing a high loss of calcium in the urine, be sure to drink plenty of water; this dilutes urine and reduces the risk of kidney stones. (This works both ways: if you have a history of kidney stone formation, be sure to get testing for excessive urinary calcium loss.)
Here at the Center for Better Bones, I suggest every person with an osteoporosis diagnosis be tested to rule out hypercalciuria. For more information see my DVD on uncovering the hidden causes of bone loss and my article about testing for bone loss.
Diet and lifestyle contribute to urine calcium loss
High salt intake
High alcohol and caffeine consumption
A diet high in sodas, refined carbohydrates and sugar
Excess protein intake
Low intake of vegetables, fruits, root crops, nuts and seeds
Low dietary intake of potassium, magnesium, vitamin K
Prolonged stress and high cortisol
Asplin JR, Donahue S, Kinder J, Coe FL. Urine calcium excretion predicts bone loss in idiopathic hypercalciuria. Kidney Int 2006;70:1463–1467.
Girón-Prieto MS, Cano-García M, Poyatos-Andújar A, et al. The value of hypercalciuria in patients with osteopenia versus osteoporosis. Urolithiasis August 2016. DOI: 10.1007/s00240-016-0909-2
Giannini S, Nobile M, Dalle Carbonare L, et al. Hypercalciuria is common and important finding and postmenopausal women with osteoporosis. Eur J Endocrinol 2003;149:209–213.
I’m Dr. Susan Brown. I am a nutritionist, medical anthropologist, writer, and speaker. Get my free weekly newsletter here.