Nutrients For Bone Health Lecture Slides PDF

NUTRIENTS FOR BONE HEALTH WEEK 13: CHAPTER 13  Overview of Bones What are bones made of? – Mineral crystals and protein (collagen) matrix Crystal provide strength/support Protein provides flexibility – Two types of bones: cortical and trabecular Bones are metabolically acti...

NUTRIENTS FOR BONE HEALTH WEEK 13: CHAPTER 13  Overview of Bones What are bones made of? – Mineral crystals and protein (collagen) matrix Crystal provide strength/support Protein provides flexibility – Two types of bones: cortical and trabecular Bones are metabolically active... – Blood vessels and nerves run through the center Bone Health is defined by... – Bone Mineral Density: how tight the mineral crystals are packed into the protein matrix  Over view of Bones How do bones grow? – Through a process of being broken down by osteoclasts and rebuilt by osteoblasts Growth in length from conception to teenage years and density can continue to accrue into young adulthood, then remodeling occurs – Bone lengthening tends to stop around 14 yrs for females and 17 yrs for males Osteoclasts remain active, but osteoblasts reduce in activity over time leading to bone loss – Bone loss is determined by genetics, nutrition, and physical activity Overview of Bones What factors affect bone health? – Genetics – Weight-bearing activity – Consumption of alcohol and animal protein – Smoking – Adequate nutrient intake – Sleep – Stress – Body weight Nutrition for Bone Health Collagen supported by... – Protein – Vitamin C Mineral Crystals supported by... – Calcium – Phosphorus – Magnesium – Fluoride – Vitamin D – Vitamin K  Calcium in Bones Most abundant mineral in the body – ~ 99% stored in the bones & teeth Func6ons – Integral part of bones, together with phosphorus – Bones serve as a bank to release calcium to body fluids with decrease in blood concentraGon – FormaGon & dissoluGon of bone minerals in constant flux Hydroxyapa6te – chief crystal in bone forma5on Fluorapa6te – fluoride displaces the hydroxy por5on; resistant to bone dissolu5on (to maintain bone integrity)  Calcium in Body Fluids ~ 1% of body Calcium is found in the body fluids Functions – Regulates transport of ions across cell membranes (nerve transmission) – Essential for muscle contraction (eg. heartbeat) – Allows secretion of hormones, digestive enzymes, neurotransmitters – Activates cellular enzymes that regulate many processes – Helps maintain normal BP – Plays essential role in blood clotting Calcium & Disease Prevention: May protect against some chronic disease – HTN – DASH diet – Not only does this recommend decrease in sodium intake, but also emphasizes the importance of increasing intake of Ca, K, MG Some research suggestive of a protective relationship between dietary calcium intake and… – Diabetes – Cholesterol – Colon cancer – Osteoporosis Calcium & Body Weight Stimulates hormone involved in the breakdown of stored fat – not all research supports this Other roles related to weight – Improved cardiovascular health – Suppressing inflammation Calcium Balance Regula'on of calcium depends on three organ systems: – Kidneys – Intes*nes – Bones Two hormones + vitamin D also regulate calcium levels – Calcitonin – Parathyroid hormone Elevated blood calcium à calcium rigor Low blood calcium à calcium tetany  Calcium Absorption Adults absorb ~30% of ingested calcium Children/Teens absorb ~50-60% Body adjusts absorption when more is needed – E.g. Pregnancy (~50% of Ca absorbed from milk) Factors that enhance calcium absorption: – Stomach acid – Vitamin D – Lactose Factors that inhibit calcium absorption: – Lack of stomach acid – Vitamin D deficiency – High P intake – Phytates (seeds, nuts, grains) – Oxalates (beet greens, rhubarb, spinach, sweet potatoes) Calcium Deficiency Inadequate intake prevents development of peak bone mass and density Osteoporosis – Adult bone loss – Brittle, fragile bones resulting in fractures – Major health problem among many older adults – Silent – no major signs or symptoms to body indicating bones are losing Ca – Measuring blood levels is not helpful Why not? Excess Calcium Excess intake from supplements may have adverse effect on kidneys – Kidney Stones – collection of calcium in the kidneys Other factors involved: – Excess oxalates, phosphates – Dehydration – Interference with other mineral absorption – Constipation Calcium Recommendations RDA: Adults: 1000mg/day (19-50yr) 1000mg/day (men 51-70yr) 1200mg/day (men >71yr) 1200mg/day women (>51yr) UL: 2500mg/d (Adults 19-50yr) 2000mg/d (Adults >51yr) Calcium Sources Good Sources – Milk/Milk Products most significant source of calcium & vitamin D Vegetables – rutabaga, broccoli, Bok choy, kale Small fishes with bones / stock form bones Almonds Calcium-for@fied foods Plant-based milk, tofu, OJ, etc. Calcium supplements What about those who are lactose intolerant?  Diet Related Health Claims “A healthy diet with adequate Calcium & vitamin D & regular PA help to achieve strong bones & may reduce the risk of osteoporosis.” “Helps to prevent bone resorption and osteoporosis.” Phosphorus 2nd most abundant mineral in the body – ~ 85% combined with Calcium in the hydroxyapatite crystals – ~15% in soft tissue (muscle and kidneys) Functions – Part of cell’s genetic material DNA, RNA / essential for growth & renewal of cells – Principal component of cell membranes forms principal part of molecules of phospholipids – Assists in energy transfer carries, stores, and releases energy – Assists many enzymes & vitamins in extracting energy from nutrients – Plays a critical role in buffering systems to maintain acid-base balance of cellular fluids  Phosphorus Deficiency – almost unknown – if it occurs, symptoms may include bone pain, muscle weakness Excess – may cause Ca excreGon – calcificaGon of kidneys Good Sources – animal protein – coRage cheese – Salmon RDA: 700mg (adults) – Milk UL: 4000mg (adults) – Steak – navy beans Vitamin D Body can synthesize it with the help of sunlight: – UV light shines on 7-dehydrocholesterol in the skin; – 7-DC transformed to inac1ve vitamin D3 precursor is absorbed directly into the blood – Liver & kidney convert precursor to ac1ve 1, 25-hydroxy vit D3 Good food sources: for;fied milk, salmon, shrimps, for;fied soy beverages Factors Affecting Sun Exposure Air pollution – clouds, smog, smoke City living – tall buildings, window glass, window screen Clothing – darker vs. lighter colors Homebound / Institutionalized / night shift work Dark skin – need longer exposure vs. light skin Season – warmer summers Sunscreen – SPF 8+ prevent synthesis Time of day – mid-day hours best Geography – lack of direct sunlight, Sept- March (Canada), Nov-Feb (US) Sunbathing – risks of premature wrinkling, skin cancer concerns Vitamin D Func0ons Helps absorp5on of dietary Calcium & Phosphorus (from skeleton, diges5ve tract, kidneys) to maintain bone integrity Acts as a hormone to raise level of blood Calcium when dietary Calcium is lacking Affects health of bones & teeth (ensures sufficient Calcium & Phosphorus available in blood) S5mulates matura5on of cells, esp. cells of the immune system to fight off infec5ons & some cancers (colon, prostate) – further evidence is needed to confirm findings Vitamin D Deficiency § Generally rare, but insufficiency is common § Produc;on of Calbindin slows (protein that binds calcium) à unabsorbed Ca passing through GI tract à less delivery of Ca to bones à calcium deficiency à osteoporosis § Risk factors: breasEeeding without supplementa;on, dark skin, lack of sunlight and unfor;fied milk, older adults § Rickets in children [protruding or ‘pigeon’ chest, beaded ribs, protruding belly, bowed legs] § Canadian recommendation: infants and children receive 10ug (400IU) vitamin D daily through diet or supplementation Osteomalacia in adults – weak or soL bones in the legs & spines Vitamin D Older Adults – Increased prevalence of deficiency Skin, liver and kidneys lose capacity to make and activate vitamin D Decreased milk intake Limited sunlight – Health Canada recommends: 400IU (10ug) of vitamin D in supplement PLUS dietary intake Vitamin D Excess May cause loss of appetite, N & V, severe psychological depression, increased blood calcium levels à calcium deposits in heart, arteries, kidneys, brain, nerves, bones Intakes 5x DRI- associated with toxicity; problems with over- supplementation & wrong fortification doses  Food Sources & Recommendations Naturally only occurs in a few foods – Eggs (yolk), fatty fish (salmon, sardines, mackerel) Fortified milk What about those who follow a plant-based dietary pattern? RDA: Adults (19-70yr): 600IU (15ug) daily Adults (>70yr): 800IU (20ug) daily UL: 4000 IU (100ug)  Diet Related Health Claims “A healthy diet with adequate Calcium & vitamin D & regular PA helps to achieve strong bones & may reduce the risk of osteoporosis.” “Vitamin D helps in the absorpBon & use of Calcium & Phosphorus”  Magnesium More than half the body’s Mg is in the bones Almost all remaining is in muscle and soU ;ssues, except ~1% that remains in extracellular fluid Func?ons – Needed for release & use of energy directly affects metabolism of calcium, vitamin D and vitamin K – Assists enzyme acOons and in normal muscular contracOon/relaxaOon Ca promotes contrac;on/Mg relaxes muscles à helps to maintain BP – Assists in nerve transmission – Holds Calcium in the enamel of teeth  Food Sources & Recommendations Good Sources: – Hard water – Legumes – seeds (especially pumpkin seeds) – nuts – whole grains – leafy-green vegetables – seafood Recommendations: RDA – Men (19–30 yr): 400 mg/day – Women (19–30 yr): 310 mg/day UL – Adults: 350 mg non-food magnesium/day  Magnesium Deficiency : – Symptoms – weakness, uncontrollable muscle spasms (fatal in heart), convulsions, hallucinaOons (mistaken for mental illness or drunkenness), appeOte loss, confusion Magnesium and Hypertension: – Adequate amounts protecOve against heart disease/hypertension – Consuming hard water (high in Ca + Mg) – have lower incidence of heart disease – Deficiency results in arterial walls constrict – increasing BP Excess: – Excess supplement or antacids – Symptoms – diarrhea, dehydraOon, acid- base imbalance – Rare, but can be fatal!  Fluoride Func?ons – help form bones & teeth as part of more decay-resistant fluorapaOte – acts directly on bacteria of plaque suppressing metabolism & reducing acid produced Good Sources – drinking water from the tap Fluorida?on – 1 ppm - as a public health measure to prevent popula;on-wide tooth decay; some water supply may contain too much fluoride – seafood Recommenda?ons AI: Men: 4 mg/day Women: 3 mg/day UL: Adults: 10 mg/day Fluoride Deficiency – suscepGbility to tooth decay and dental caries Excess – Fluorosis – irreversible discolora,on of teeth due to wider availability of fluoride- containing products [toothpaste, mouthwash, supplements] or excess fluoride in tap water – Mo/led teeth enamel – not a health problem; more of a cosmeGc problem  Vitamin K Fat soluble vitamin Do you remember the main role and function from last week’s discussion for blood health? Role in relation to bone health – Necessary for the synthesis of protein needed in bone formation together with vitamin D – Osteocalcin: vitamin K needed to bind this protein to minerals needed for bone formation – Adequate vitamin K can decrease bone turnover and prevent fractures HIGHLIGHT 13 Osteoporosis & Calcium  Development of Osteoporosis Incidence: – Predict 1 in 3 women and 1 in 5 men will experience an osteoporotic fracture in their life – Increase burden on healthcare system – cost for repair, hospital stay – Impact on quality of life for the individual Review of the two compartments of bones: – Trabecular – Cortical Diagnostics – dual-energy X-ray absorptiometry (DEXA) scan to measure bone mineral density  Risk Factors: Protective Factors: Non-Modifiable: Modifiable: Non-Modifiable: Modifiable: Older age Sedentary lifestyle Younger age Inclusion of weight- Female gender Inadequate intake of Male gender bearing activity Caucasian, Asian, Ca and vitamin D Larger frame Adequate Ca and or Hispanic Excess alcohol intake vitamin D heritage Low BMI Moderate alcohol Small frame Cigarette smoking intake Maternal Hx of Certain meds No smoking osteoporosis Estrogen therapy fracture or High BMI personal fracture Bone density Estrogen assessment and deficiency treatment if needed Age and Bone Calcium Gender & Hormones After age, gender is next most important predictor of osteoporosis Sex hormones regulate bone turnover Impact of menopause – Reduced estrogen levels increase release of cytokines à inflammation à accelerated bone loss – Estrogen therapy – need to weigh pros and cons – Use of soy and phytochemicals - soy can mimic actions of estrogen in the body – again need to weigh pros and cons Bone loss in males – Decrease testosterone levels (d/t diseased testes or age) play a role  Other Contributing Factors Genetics –play a role, however what exactly this is still remains unclear – May determine POTENTIAL peak bone mass and rate of bone loss later on – Environmental factors also determine if this potential is achieved Ethnicity Physical activity – Muscles pull on bones which stimulates them to become denser – Inclusion of strength-training exercises 2x/week + regular weight-bearing aerobic activities Body weight – Heavier weight places increased stress on bones, increasing density – Weight loss and restricted energy intake decreases bone density Smoking & alcohol – Result in lower bone density – Alcohol: increases excretion of Ca in urine, slows bone formation, stimulates bone breakdown  Bone Growth Goals: Grow strong bones – ages 2-12 y. – Consume milk – Engage in physical activity – Limit screen behavior – Drink fluoridated water Achieve peak bone mass – 13-30 y – Consume milk – Engage in physical activity – Avoid smoking/drinking – Drink fluoridated water Maximize bone retention – 31-50 y – Recommend bone strengthening exercises and calcium supplements for most Minimize bone loss – 51+ y – + bone density test – Bone restoring medications & supplements Calcium Supplements If able, aim to obtain from food first Consult a healthcare professional prior to starting d/t risks of excess amounts Multivitamin and mineral supplements generally contain minimal amounts Generally sold as compounds of calcium carbonate (40% Ca), citrate (21%), lactate (13%), gluconate (9%) Ensure intake from food and supplements does not excess the UL Take a low dose supplement and take several times throughout the day in increments