Chapter 11 Lecture Chapter 11: Nutrients Involved in Bone Health © 2017 Pearson Education, Inc Bones • Bones are living organs that contain • Bone tissue • Cartilage • Connective tissue • Nerves and blood run within channels in bone to support its activities © 2017 Pearson Education, Inc Bones (cont.) • Bone provides strength and flexibility • Contains about 65% minerals, providing the hardness of bone • Contains 35% organic structures for strength, durability, and flexibility (collagen) • Hydroxyapatite: mineral crystals around collagen designed to bear weight © 2017 Pearson Education, Inc © 2017 Pearson Education, Inc Bone Tissues • Cortical bone (compact bone) • 80% of the skeleton • Outer surface of bone • Trabecular bone (spongy bone) • 20% of the skeleton • Inside of bones (scaffolding) • Supports outer cortical bone • Faster turnover rate (sensitive to hormonal changes and nutritional deficiencies) © 2017 Pearson Education, Inc © 2017 Pearson Education, Inc Bone Development • Bone growth: increase in bone size • Complete by age 18 in girls; age 21 in boys • Bone modeling: shaping of bone • Complete by early adulthood • Exercise and overweight increase thickness • Bone remodeling: recycling of bone tissue © 2017 Pearson Education, Inc © 2017 Pearson Education, Inc Bone Development (cont.) • Bone density: compactness of bones • Peak bone density: when bones are strongest • Factors associated with a lower peak bone density: • Late pubertal age in boys • Late onset of menstruation in girls • Inadequate calcium intake • Low body weight • Physical inactivity during the pubertal years © 2017 Pearson Education, Inc Bone Remodeling • Resorption: surface of bones is broken down by osteoclasts (cells that erode the surface of bones) • New bone matrix formed by osteoblasts (bone builder cells) • Synthesize new bone matrix by laying down collagen-containing component of bone © 2017 Pearson Education, Inc Fluoride • Trace mineral, stored in teeth and bones • Combines with calcium and phosphorus to form fluorohydroxyapatite to form teeth • Functions of fluoride • Develop and maintain teeth and bones • Combines with calcium and phosphorus to protect teeth from bacteria • Stimulates bone growth © 2017 Pearson Education, Inc Fluoride (cont.) • Recommended intake • AI varies by gender and increases with age, ranging from to mg/day • Sources of fluoride • Fluoridated dental products • Fluoridated water (not in bottled water) © 2017 Pearson Education, Inc Fluoride (cont.) • What if you consume too much fluoride? • Fluorosis (excess fluoride) increases the protein content of tooth enamel and makes teeth porous; teeth become stained and pitted • What if you don't consume enough? • Dental caries (cavities) © 2017 Pearson Education, Inc © 2017 Pearson Education, Inc Osteoporosis • Most prevalent disorder affecting bone health • Characterized by: • Low bone mass • Deterioration of bone tissue • Fragile bones leading to bone-fracture risk • Bone compaction: decreased height • Shortening and hunching of the spine: kyphosis (dowager's hump) © 2017 Pearson Education, Inc • Osteoporitic vertebrae (left) and healthy vertebrae (right) © 2017 Pearson Education, Inc © 2017 Pearson Education, Inc Osteoporosis (cont.) • Risk factors include: • Age • Gender • Tobacco, alcohol, and caffeine • Poor nutrition • Physical inactivity © 2017 Pearson Education, Inc © 2017 Pearson Education, Inc Osteoporosis Risk: Age • Bone mass decreases with age • Age-related hormonal (estrogen and testosterone) changes influence bone density Decreased vitamin D metabolism with age â 2017 Pearson Education, Inc Osteoporosis Risk: Gender And Genetics • 80% of Americans with osteoporosis are women • Women have lower bone density than men • Low estrogen production increases bone loss: postmenopausal women and adolescent girls (extreme dieting) • Caucasian women of low body weight with firstdegree relative (mother or sister) with osteoporosis at greater risk © 2017 Pearson Education, Inc Osteoporosis Risks: Smoking/Poor Nutrition • Cigarette smoking effects hormones that influence bone formation and resorption • Alcoholism is associated with fractures • Caffeine increases urinary calcium loss • Dietary protein and calcium interaction • Low calcium and vitamin D intakes result in low bone density © 2017 Pearson Education, Inc Osteoporosis Risk: Physical Inactivity • Regular exercise postively stresses bone tissues, stimulates bone density • Weight-bearing activities (walking, jogging) can help increase bone mass © 2017 Pearson Education, Inc Nutrition and Osteoporosis • Fruit and vegetable consumption associated with improved bone health • Good sources of vitamins C and K, as well as magnesium • Protein: effect on bone health is controversial • High intake may increase calcium loss • Low protein intake also associated with bone risks • Calcium & vitamin D are important throughout the life span • Sodium: high intakes appear to have a negative impact, but studies are inconclusive © 2017 Pearson Education, Inc Treatment for Osteoporosis • There is no cure for osteoporosis • Factors that slow the progression of osteoporosis: • Adequate calcium and vitamin D intake • Regular (weight-bearing) exercise • Resistance training • Certain medications (may have side effects) © 2017 Pearson Education, Inc ... Tissues • Cortical bone (compact bone) • 80% of the skeleton • Outer surface of bone • Trabecular bone (spongy bone) • 20% of the skeleton • Inside of bones (scaffolding) • Supports outer cortical... • Can be synthesized by the body from exposure to UV rays from the sun • Considered a hormone: synthesized in one location and regulates activities in other parts of the body © 2017 Pearson Education,... sun in the winter (latitude of more than 40°N or more than 40°S) • Darker skin (more melanin pigment) reduces the penetration of sunlight • People >65 years have decreased capacity to synthesize