Malabsorption syndrome
Also called: nutrient malabsorption bone loss
What it means
Malabsorption syndrome is when the gut fails to properly absorb nutrients like calcium and vitamin D, which are essential for strong bones.
Without enough absorbed calcium and vitamin D, your body borrows from bone, raising your risk of osteoporosis over time.
Malabsorption syndrome means your gut can't properly absorb nutrients from food, even if you're eating enough. For bones, the biggest concerns are calcium and vitamin D — both need a healthy small intestine to get into your bloodstream. When absorption fails over time, your body pulls calcium from bone to keep blood levels steady, which weakens bone over the years.
Common causes include celiac disease, which damages the lining of the small intestine; Crohn's disease and other inflammatory bowel conditions, which combine poor absorption with inflammation that activates bone-removing cells; and bariatric surgery, especially procedures that bypass the part of the intestine where calcium is normally absorbed. Each of these can lead to secondary hyperparathyroidism, where the parathyroid glands work overtime trying to compensate, further accelerating bone loss.
If you have one of these conditions, your doctor may recommend monitoring bone density over time and checking vitamin D and calcium status, with supplementation tailored to your situation — sometimes using forms that absorb better when stomach acid is low. Any decisions about testing, supplements, or treatment should be made with your doctor, since the right approach depends on the underlying condition and how severe the absorption problem is.
When your gut can't absorb enough calcium and vitamin D, your body borrows from bone instead.
Where this leads
WordSince vitamin D is key to absorbing calcium, see how a deficiency in it alone can weaken bones over time.
Where the Academy teaches it
This page is the short version. The lessons teach it in full, with the context around it and a quiz to lock it in.
Related words
Celiac disease is an autoimmune condition that damages the small intestine, often reducing absorption of calcium,…
Crohn's disease is a digestive condition that inflames and damages the gut lining, which can reduce the body's…
Bariatric surgery (gastric bypass or sleeve) changes digestion in ways that can speed up bone loss, mainly through…
Secondary hyperparathyroidism is when the parathyroid glands make too much PTH because of a problem elsewhere, like…
Vitamin D deficiency means your body doesn't have enough vitamin D, which is needed to absorb calcium and keep bones…
Calcium is the main building-block mineral in bone, and since your body can't make it, you need to get it from food…
Education only, not medical advice. Decisions about tests, medications and treatment belong with your own doctor. OsteoStrong does not diagnose, treat or cure any disease.
