Is Low-Carb Dieting Linked to Osteoporosis Risk and Bone Loss?

What the Research Says About Low-Carb Diets and Bone Loss

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Osteoporosis has been associated with low carb dieting, but the evidence is scant and no large-scale study has found causation. One of the frequent claims of people opposed to low-carb diets is that it can cause bone loss. The reason for this fear is that increasing protein in the diet beyond a certain level will increase calcium excretion in the urine. Some think this translates to bone loss or a heightened osteoporosis risk.

Some have assumed the additional "loss" of calcium is coming from the bones, and that low-carb diets, which are generally higher in protein, would lead to bone loss over the long term. Here we debunk this common low carb diet myth.

What the Research Says About Low Carb-High Protein Diets and Bone Loss

Although there's more research being done, scientists conducting the studies about low carb dieting and bone loss have been surprised by the findings that more protein in the diet at the very least causes no harm, and in most studies, actually improves bone density rather than causing bone loss. While many people think of calcium when it comes to bones, bones are one of the most protein-dense tissues in the body. Several of the studies suggest that increased protein intake improves calcium absorption from food.

Diet History Matters When Starting a Low Carb Diet

Whether adding protein improves bones may be partly a function of how much protein the person was eating to begin with.

But, it is interesting that in several studies comparing the bones of people eating the standard “recommended daily requirement” of protein (0.8 grams of protein per kilogram of body weight) with those eating more protein found that those who ate more protein than the standard recommendation had less bone loss.

This is yet another confirmation of the importance of protein when it comes to bone density, a finding that goes against conventional wisdom about low carb diets and bone loss.

Low-Carb Dieters Maintain Bone Density

A 2006 study focused on low-carb diets, rather than protein intake per se. Subjects were limited to 20 grams of daily carbohydrate for one month, and to 40 grams of carb for an additional two months. There was no problem with increased “bone turnover” (a short-term indication of potential bone loss) during this period of time. The lead scientist on the study, John L. Carter, has been quoted as saying that he was “shocked” at the results. This study, though small, adds another kink in the case of low carb dieting causing bone loss. Rather, it appears that the two are more closely related to protein intake, which, when it comes to low carb dieting, may actually be an improvement in bone density rather than a loss.

Tips to Maintain Bone Density

Eating enough protein is not the only way to protect our bones.

Here are five tips to support bone health:

Learn more about osteoporosis prevention.

Dietary protein, calcium metabolism, and skeletal homeostasis revisited. Am J Clin Nutr. 2003 Sep;78(3 Suppl):584S-592S.

Effect of dietary protein supplements on calcium excretion in healthy older men and women. , J Clin Endocrinol Metab. 2004 Mar;89(3):1169-73.

Low protein intake: the impact on calcium and bone homeostasis in humans. J Nutr. 2003 Mar;133(3):855S-861S. This chart is of special interest.

Protein consumption is an important predictor of lower limb bone mass in elderly women. Am J Clin Nutr. 2005 Jun;81(6):1423-8.

The impact of dietary protein on calcium absorption and kinetic measures of bone turnover in women., J Clin Endocrinol Metab. 2005 Jan;90(1):26-31

The effect of a low-carbohydrate diet on bone turnover. Osteoporos Int. 2006 May 23.

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