Summary: In adolescents and young adults with type 1 diabetes, 24 weeks of a low-carbohydrate diet did not significantly change bone turnover markers (CTX, P1NP) versus a Mediterranean diet, though it trended toward lower alkaline phosphatase and reduced calcium and magnesium intake.
PICO Summary
| Element | Detail |
|---|---|
| Population | 40 adolescents and young adults aged 12–21 with type 1 diabetes. |
| Intervention | Low-carbohydrate diet for 24 weeks (median carbohydrate 86 g/day). |
| Comparison | Mediterranean diet over the same period (median carbohydrate 130 g/day). |
| Outcome | No significant change in CTX or P1NP in either arm. Low-carb arm had lower alkaline phosphatase (p=0.009) and reduced calcium and magnesium intake, but these did not survive false-discovery-rate correction. |
Low-Carb vs Mediterranean Diet & Bone in T1D
RCT · type 1 diabetes · 24 weeks
Over 24 weeks, neither a low-carb nor a Mediterranean diet significantly changed bone turnover markers (CTX, P1NP) in young people with type 1 diabetes. Reassuring short-term data, but turnover markers are not bone density or fractures.
Expert Commentary
Low-carbohydrate eating is increasingly popular among my younger type 1 patients chasing tighter glucose, and bone is precisely the thing I worry about when an adolescent restricts a whole food group during peak bone-mass accrual. So I read this looking for harm, and the reassuring headline is that I did not find much: over six months neither diet meaningfully disturbed bone turnover markers. I am careful not to overstate that comfort. The alkaline phosphatase dip and the lower calcium and magnesium intake did not survive correction for multiple testing, so I treat them as hypothesis-generating rather than real, but the direction is a useful warning that restrictive diets can quietly erode bone-relevant nutrients. Turnover markers are also not bone density or fractures, and twenty-four weeks is far too short for a skeleton being built. Can I use this with my patients? Yes, as short-term reassurance that a supervised low-carb approach is not acutely bad for bone, paired with active attention to calcium and magnesium intake. I would want longer studies with density and fracture endpoints before offering anything firmer in this fracture-prone group.
References
Levran N, Levek N, Levy-Shraga Y, et al. Bone turnover markers (CTX and P1NP) following low-carbohydrate and Mediterranean diet interventions in adolescents and young adults with type 1 diabetes. Nutrients. 2025;17(24):3935. doi:10.3390/nu17243935