Can a Kale Supplement Boost Bone Mineral Density in the Spine?
Kale is chock full of soluble calcium (Ca) and vitamin K1. Research has shown that its absorbability of calcium is equal to or better than the absorbability of milk, and kale may also be more effective at boosting bone mineral density (BMD). But can kale boost BMD specifically in the spine and hip?
Recently, Japanese researchers conducted a 1-year open-label study that examined the impact oral kale supplementation had on postmenopausal women.
Their results were published in the paper “Effects of kale supplementation on bone mineral density and bone metabolic markers in postmenopausal women,” and it was presented at the 2011 Annual Meeting of the American Society of Bone and Mineral Research.
The study included a total of 13 postmenopausal women.
All participants drank a beverage that contained 9.5 g of a powdered kale product (Ca: 126.6 mg; 5.4 mg/packet). They took the kale product 2 or 3 times a day for a total of 1 year.
Serum Ca and bone metabolic markers were assessed at the beginning of the study as well as at 3 months, 6 months, and 12 months during the study. The bone metabolic markers that were measured were serum NTx, urinary NTx, serum OC, and serum BAP.
Lumbar spine (L2-L4) BMD and femoral neck BMD were measured using dual-energy x-ray absorptiometry (DXA) at the beginning of the study and at 6 months and 12 months during the study.
Researchers noted that according to daily records from study participants, average Ca intake was 227.9 mg to 354.5 mg and average vitamin K1 intake was 241.6 mcg to 375.8 mcg.
When compared to the baseline data, serum NTx levels significantly decreased after 3 months (p<0.05). This was maintained throughout the study at both 6 months and 12 months (p<0.05).
The research team also noted that at 12 months, serum BAP levels had significantly decreased (p<0.05), but urinary NTx did not significantly decrease. Furthermore, in the lumbar spine, BMD measurements showed a tendency to increase.
At the end of the study, improvement in both bone metabolic markers and bone mineral density (including BMD in the lumbar spine) was observed in postmenopausal women who took oral kale supplementation.