Is Bone Broth a Good Source of Calcium?
Bone broth is very popular right now with some people claiming health advantages from consuming bone broth. Currently the benefits are somewhat controversial and there are limited studies on the health effects. There is some concern that since bones are known to sequester heavy metals, there may be a risk of high lead levels in bone broth. Some analyses of bone broths have found high lead levels and others have not noted significant levels. If you choose to consume bone broth do so in moderation. There is one unusual report of a man who became sick due to hypercalcemia and hypervitaminosis D, after drinking 1 to 2 liters of soup prepared by prolonged boiling of long beef bones, at least 3 days per week, for 6 months prior to becoming ill. (Moderation is generally key and this is not moderate intake)
The nutrient content of bone broth can vary significantly and depends on the quantity and nutrient levels of the ingredients. The source of the bones and what the animal ate, how much bone is in the recipe, if the meat on the bone was previously cooked, the length of time the broth cooks, and if acid was used in the recipe can all contribute to the nutrient content.
One older study found calcium ranging from 12 to 68 mg. and a more recent analysis found 92 mg. calcium in one cup. The calcium level of most commercially available bone broths also varies, but most are not significant sources.
One exception is Bare Bones Chicken or Turkey Bone Broth, which contains 217 mg. of calcium in an 8 ounce serving. Bare Bones is also higher in protein than most other commercially available bone broths. Their website describes their cooking process as slowly simmering the broth using steam for 24 hours, rather than an open flame. Then they remove moisture from the broth to concentrate it. Bare Bones website indicated they are currently awaiting results for lead testing of their broths and will publish the results as soon as they receive them. When I questioned Bare Bones about the high calcium content of their bone broth, compared to their own beef bone broth which is much lower in calcium (26 mg), they generously shared the nutritional analysis and a possible explanation for the difference. Their Chief Broth Officer pointed out that beef and chicken differ in a couple of ways. First, beef bones, joints, etc. are bigger and have less surface area than chicken, making it a bit harder to extract all the nutrients. Second, their chicken broth uses a significant amount of feet, which contain a tremendous amount of cartilage/connective tissue. They also pointed out that chicken frames and feet contain a lot more connective tissue/cartilage than beef bones. Bare Bones broth is not inexpensive and availability is not yet widespread so you may have to order directly from them and pay shipping on orders below $150.00. If you are looking for some variety in your calcium and protein sources and can afford the price give it a try.