Does Kale Supplementation Boost Bone Mineral Density in Postmenopausal Women?
It’s well known that kale is rich in vitamin K1 and soluble calcium (Ca). Kale’s absorbability of calcium is equal to or better than that of milk, and it may be effective at boosting bone mineral density (BMD).
In a recent study out of Japan, researchers looked at the impact of kale supplementation taken orally in postmenopausal women.
Results of the study were published in the paper “Effects of kale supplementation on bone mineral density and bone metabolic markers in postmenopausal women.” The paper was presented at the 2011 Annual Meeting of the American Society of Bone and Mineral Research.
This year-long open-label study included 13 postmenopausal women. Study participants took a beverage that contained 9.5 g of a powdered kale product (Ca: 126.6 mg; 5.4 mg/packet). The women took this kale product 2 or 3 times a day for a total of 12 months.
Serum Ca and bone metabolic markers (which included serum NTx, urinary NTx, serum OC, and serum BAP) were assessed at the beginning of the study, and then again at 3 months, 6 months, and 12 months.
BMD of the lumbar spine (L2-L4) and femoral neck were measured using dual-energy x-ray absorptiometry (DXA) at the beginning and then again at 6 months and 12 months during the study.
The research team found that according to a daily record of the participants, average Ca intake was 227.9 mg to 354.5 mg and vitamin K1 intake was 241.6 mcg to 375.8 mcg.
It was noted that comparing to baseline data, after 3 months (p<0.05), serum NTx significantly decreased, but it was maintained at 6 months and 12 months (p<0.05) of the study.
In addition, serum BAP level at 12 months significantly decreased (p<0.05), but urinary NTx did not decrease significantly.
It was also noted that BMD measurements showed a tendency of increase in the lumbar spine. Researchers concluded that when taking oral kale supplementation, there is an overall improvement in bone mineral density and bone metabolic markers in postmenopausal women.