Jaymie Ticknor Intro Nutrition Science 2460 Sect 002 23 June 2014 Nutrients Involved in Bone Health Chapter 9 How Do Our Bodies Maintain Bone Health The Composition of Bone Provides Strength and Flexibility Collagen a protein that forms strong fibers in bone and connective tissue Provides strength durability and flexibility Hydroxyapatite calcium and phosphorus form these tiny crystals that cluster around the collagen fibers Cortical Bone Compact Bone a dense bone tissue that makes up the outer surface of all bones as well as the entirety of most small bones of the body Trabecular Bone Spongy Bone a porous bone tissue that makes up only 20 of our skeleton and is found within the ends of the long bones inside the flat bones sternum ribs and most bones of the skull and inside the bones of the pelvis Bone fractures caused by aging are usually found in this type of bone The Constant Activity of Bone Tissue Promotes Bone Health Bone Growth and Modeling Determine the Size and Shape of Our Bones Bone Modeling process by which the shape of our bones is determined Bone Density the degree of compactness of bone tissue reflecting the strength of the bones Peak bone density is the point at which a bone is strongest Bone Remodeling Maintains a Balance Between Breakdown and Repair Remodeling the two step process by which bone tissue is recycled Includes the breakdown of existing bone and the formation of new bone Resorption the process by which the surface of bone is broken down by cells called osteoclasts Outpaces bone formation at age 40 grooves into the bone matrix Osteoclasts cells that erode the surface of bones by secreting enzymes and acids that dig Osteoblasts cells that prompt the formation of new bone matrix by laying down the collagen containing component of bone which is then mineralized Osteoporosis a disorder characterized by low density bones that fracture easily How Do We Assess Bone Health Dual Energy X ray Absorptiometry DXA or DEXA currently the most accurate T score a comparison of an individual s bone density to the average peak bone density tool for measuring bone density of a 30 year old healthy adult A Profile of Nutrients That Maintain Bone Health Calcium Calcium is the most abundant mineral in the body Parathyroid Hormone PTH a hormone secreted by the parathyroid gland when blood Functions of Calcium calcium levels fall Also known as parathormone it increases blood calcium levels by stimulating the activation of vitamin D increasing reabsorption of calcium from the kidneys and stimulating osteoclasts to break down which releases more calcium into the bloodstream Calcitonin a hormone secreted by the thyroid gland when blood calcium levels are too high Inhibits the actions of vitamin D preventing reabsorption of calcium in the kidneys limiting calcium absorption in the small intestine and inhibiting the osteoclasts from breaking down bone Inhibits absorption of calcium by the kidneys and intestine Calcium Tetany a condition in which muscles experience twitching and spasms as a result of inadequate blood calcium levels Calcium Rigor a failure of muscles to relax which leads to a hardening or stiffening of the muscles Caused by high levels of blood calcium How Much Calcium Should We Consume Bioavailability the degree to which our body can absorb and utilize any given nutrient Our bodies cannot absorb more than 500 mg of calcium at any one time Oxalate found in plant foods binds dietary calcium making it less available for absorption What Happens If We Consume Too Much Calcium Hypercalcemia a condition marked by an abnormally high concentration of calcium in What Happens If We Don t Consume Enough Calcium Hypocalcemia a condition characterized by an abnormally low concentration of calcium Blood calcium levels fall PTH stimulates osteoblasts to breakdown bones and release Vitamin D is considered a hormone because it is made in one part of the body yet Vitamin D regulates various activities in other parts of the body Regulates calcium absorption and utilization Cholecalciferol vitamin D3 a form of vitamin D found in animal foods and the form we Calcitriol the primary active form of vitamin D in the body The vitamin D sufficiency line is the northernmost point at which adequate vitamin D synthesize from the sun synthesis is possible Vitamin D Fish Fortified Foods Supplements or Sunlight into the body the blood in the blood calcium Ergocalciferol vitamin D2 a form of vitamin D found exclusively in plant foods What Happens If We Don t Consume Enough Vitamin D Rickets a vitamin D deficiency disease in children Signs include deformities of the skeleton such as bowed legs and knocked knees Severe rickets can be fatal Osteomalacia a vitamin D deficiency disease in adults in which bones become weak and prone to fractures Vitamin K Phylloquinone the primary dietary form of vitamin K and also formed found in plants Menaquinone animal form of vitamin K produced by bacteria in the large intestine Prothrombin a protein that plays a critical role in blood clotting Osteocalcin a protein associated with bone turnover This is a coenzyme in the regulation of blood coagulation Phosphorus How Much Phosphorus Should We Consume Milk Displacement Effect soft drinks take the place of milk or calcium fortified milk alternatives in our diets depriving us of calcium and vitamin D Magnesium Functions of Magnesium Magnesium is a critical cofactor needed for an enzyme to be active for more than 300 enzymes systems and is necessary for the production of ATP Deficiencies disrupt mineral retention by kidneys What Happens If We Consume Too Much Magnesium Hypermagnesemia a condition marked by an abnormally high concentration of What Happens If We Don t Consume Enough Magnesium Hypomagnesemia a condition characterized by an abnormally low concentration of magnesium in the blood magnesium in the blood Fluoride Functions of Fluoride Fluorohydroxyapatite fluoride combines with calcium and phosphorus to form this More resistant to destruction by acids and bacteria than is hydroxyapatite What Happens If We Consume Too Much Fluoride Fluorosis a condition marked by staining and pitting of the teeth caused by an abnormally high intake of fluoride