Calcium and Vitamin D in Promotion of Postmenopausal Bone Health

What is the impact of daily oral supplementation of vitamin D3 (cholecalciferol) plus calcium on the incidence of hip fracture in older people? A systematic review and meta-analysis

INTRODUCTION

Hip fractures have a huge impact in reducing the quality of life and increasing mortality. This review aims to assess the impact of daily oral supplementation of vitamin D3 plus calcium on the incidence of hip fracture in people over 65 years.

METHODS

PRISMA guidelines were followed and RCTs that evaluated the effectiveness of daily oral supplementation of vitamin D3 plus calcium in preventing hip fracture in adults over 65 years were included in the study. The databases such as Cochrane Library, Embase, Medline, PubMed, CINAHL, Web of Science and Scopus were searched from October 2019- January 2020.The Cochrane risk of bias tool was used to check the quality of the included studies. A meta-analysis with fixed effect model using Review Manager (Revman 5.3) was used to analyse the data.

RESULTS

The meta-analysis of seven RCTs on vitamin D3 plus calcium supplementation and hip fracture (n = 12,620) identified odds ratio (OR) of 0.75; 95% Confidence interval (CI): 0.64, 0.87; p = .0003. Daily oral supplementation of 800 IU of Vitamin D3 plus 1200 mg of calcium was found more effective (n = 5676 participants; OR = 0.69; 95% CI: 0.58, 0.82; p < .0001) than daily oral supplementation of 800 IU of Vitamin D3 plus 1000 mg of calcium (n = 6555,OR = 1.08; 95% CI: 0.74, 1.56; p = .70) in reducing hip fracture. A meta-analysis of the seven RCTs to identify the incidence of non-vertebral fracture gave the OR of 0.80; 95% CI: 0.72, 0.89; p < .0001. A meta-analysis of three RCTs on femoral neck bone mineral density (BMD) (n = 483) gave a mean difference of 1.21; 95% CI: -0.79, 3.20; p = .24.

CONCLUSION

Daily oral supplementation 800 IU of vitamin D3 plus 1200 mg of calcium reduces hip fracture and non-vertebral fracture in older people. Administering vitamin D3 and calcium supplements had no effect in increasing the femoral neck BMD.

IMPLICATIONS FOR PRACTICE

Even though it is evident from the review that optimal daily intake of vitamin D3 plus calcium supplementation help in the prevention of fracture, it is only one essential element in fracture prevention. Also, people who are on dietary supplements should be compliant with same for better result. Efforts to prevent bone loss and osteoporosis should begin from an early age. It includes maintaining a healthy lifestyle, optimal intake of calcium and vitamin D3, proper nutrition, adequate exposure to sunlight, exercise etc. Proper education on healthy lifestyle, avoiding risk factors like smoking, caffeine, alcohol and awareness of bone health should continue throughout life with emphasis during menopause when increased bone loss is expected.

Beneficial effects of phytoestrogens and their metabolites produced by intestinal microflora on bone health

Phytoestrogens are a class of bioactive compounds derived from plants and exert various estrogenic and antiestrogenic effects. Estrogen deficiency osteoporosis has become a serious problem in elderly women. The use of ovariectomized (OVX) rat or mice models to simulate the postmenopausal condition is well established. This review aimed to clarify the sources, biochemistry, absorption, metabolism, and mode of action of phytoestrogens on bone health in intervention studies. In vitro, phytoestrogens promote protein synthesis, osteoprotegerin/receptor activation of nuclear factor-kappa B ligand ratio, and mineralization by osteoblast-like cells (MC3T3-E1). In the OVX murine model, administration of phytoestrogens can inhibit differentiation and activation of osteoclasts, expression of tartrate-resistant acid phosphatase, and secretion of pyridinoline compound. Phytoestrogens also enhance bone formation and increase bone mineral density and levels of alkaline phosphatase, osteocalcin, osteopontin, and α1(I) collagen. Results of mechanistic studies have indicated that phytoestrogens suppress the rate of bone resorption and enhance the rate of bone formation.

Antiosteoporotic effects of Lactobacillus -fermented soy skim milk on bone mineral density and the microstructure of femoral bone in ovariectomized mice

Osteoporosis is a major skeletal disease associated with loss of estrogen in postmenopausal women. In this study, Lactobacillus paracasei subsp. paracasei NTU 101 (NTU 101F) and Lactobacillus plantarum NTU 102 (NTU 102F) were used as starters to ferment soy skim milk. This was then used as a nutritional supplement for 8 weeks to ovariectomized (OVX) mice. This study reveals that soy skim milk fermented with lactobacilli can increase the contents of aglycone isoflavones, soluble calcium, and vitamin D(3). The trabecular bone volumes and trabecular number of the distal femur in mice fed NTU 101F increased by a factor of 1.48 and 1.74 compared with the OVX group. The bone network density and thickness of the distal metaphyseal trabecular in mice fed NTU 101F and Fosamax was significantly greater than that of OVX mice. These results suggest that fermented soy skim milk can attenuate bone loss in OVX mice and lower the risk of osteoporosis.