Ryan Probst and Dr. Robert T. Davidson, Department of Nutrition Dietetics and Food Sciences
Osteoporosis is a growing problem in the world today. With the aging population of the United State’s Baby Boomer generation, healthcare research is shifting dramatically to combat the rising rates of diseases associated with our aging population majority. Compiled with this majority of elderly people is the fact that Americans are living longer. We must face the challenges associated with the aging human body. Osteoporosis is an age-related disease. This study has added to the research available on osteoporosis and has provided enhanced methods to treat osteoporosis, a major problem especially in postmenopausal women. Several Asian studies report an increase in bone density due to Vitamin K supplementation; however, until now these studies had not been reproduced with the same reported success outside Asia. The results of this study are now a foundation for future research studying the effects of vitamin K on bone integrity. By demonstrating the efficacy of vitamin K in the treatment of osteoporosis in rats, this research is instrumental in identifying possible future nutritional therapies in humans.
The hypothesis was that the animals fed diets high in vitamin K and high in w-3 fatty acids found in fish oil would have significantly stronger femur tensile strength than the experimental control groups. This would support the notion that vitamin K supplementation with w-3 fatty acids does have effects on osteoporosis in ovariectomized rats. This information is important in the fight against osteoporosis in humans.
The results of this study were submitted for publication in The Journal of Nutrition, and were presented at the convention of Experimental Biology in Washington D.C. in the summer of 2007. A poster was made of our experiment with results and is displayed in the Eyring building on BYU campus
The bone tensile strength of the femurs was evaluated by three-point bending using BYU’s new instron machine. I harvested the bones immediately postmortem, removing all soft tissues. I wrapped them in saline soaked towels, then sealed them in plastic bags and stored them at -80°C. Bones were thawed slowly over the course of 12 hours before testing. They were kept in a saline solution while waiting for testing. The diaphysis of the femur was first tested. An actuator was used with a single point of application on the femur. The loading rate was obtained by experimentation beforehand on a separate trial rat femur. Load was applied over a single-cycle ramp function at a constant displacement rate of 10 mm/min until the femur fractured. Testing of tensile strength was concluded in May 2007. The test progresses force displacements and records them using computer analysis software. The computer generates load-deformation curves for each femur. Load is represented as the bending moment (N•m). Values for stiffness are calculated as the slope of the linear regression fit from the straight portion of the curve, and failure is defined as the point of bone fracture, or when the central load applicator visibly crushes the cortex. The breaking stress was calculated with the formula: BS Max = Mmax C/I = (FLC/4I), where BS = breaking stress (9N/m2), F = load at fracture, L = distance between end supports, and c= y1/2 = distance from the centroid to the surface, I = area moment of inertia. Values were reported as a group mean ± standard deviation. The bone ash data showed a level of significance between the control group and the sham group of rats which indicates a direct connection between treatment and non-treatment. This is very promising and we are currently working on new experiments to strengthen our results even further.
Our hypothesis was shown to be positive by the results which we obtained in that the diet high in vitamin K and high in omega-3 fatty acids significantly decreased the measurable effects of osteoporosis. Our statistical analysis showed a .05 p-value in the Dunnett’s Upper One-Sided Multiple-Comparison Test with Control, the only two groups that were significantly different from the control group (normal vitamin K and low omega-3) were the SHAM group and the treatment group (high vitamin K and high omega-3). As anticipated beforehand, the SHAM group was significantly different from the experimental group, showing that the ovariectomized rats made a proper model for the effects of the osteoporosis disease process. The treatment group we examined proved to show significant difference in the experimental tests, which demonstrated the treatment diet had a significant effect in decreasing osteoporosis. It was concluded from the findings that normal and high omega-3 and omega-6 fatty acids had no preventative effect on bone loss, but we also found that pharmacological vitamin K significantly reduced bone loss in ovariectomized rats and increased femoral strength and structural integrity of the femurs of these animals.
Experimental results which indicate that other diet groups not high in omega-3 or vitamin k were not significantly different from the control group indicates that these other diets do not have an effect in reducing the negative effects of osteoporosis. This can explain the difference in results between the Asian experiments and the other researcher’s results. Asian researchers used diets high in omega-3 fatty acid along with their high vitamin k diet. Other researchers use high vitamin K by itself or coupled with high omega-6, which is commonly used in the United States. Our results indicate that the diet which significantly decreases the effects of osteoporosis is the diet used by the Asian researchers, namely diet high in vitamin K and also high in omega-3fatty acid. Diets of any other combination showed insignificant results. The results from femur tensile strength tests show data which indicates a diet high in vitamin K and high in omega-3 fatty acids can slow and even stop the degenerative effects of osteoporosis in bone mineral.
