Nutrients & Bone Metabolism

Nutrients & Bone Metabolism

1. Bone & Skeleton

   • Function
     • Stores Calcium & Phosphate
       • Protection & Support
         • Movement (Attach to muscle)
           • Bone Marrow (formation of blood cells)
   • Bone Composition
     • 99% of Calcium are in the bones
       • Calcium carbonate/phosphate w protein
   • Bone Turnover
     • Childhood
       • Formation > Breakdown
     • 35-45y/o
       • Formation = Breakdown
         • Calcium & Vit D crucial
     • 45+ y/o
       • Breakdown > Formation
     • Menopause
       • Breakdown >> Formation
         • Hormone replacement therapy

2. Minerals

   • Calcium
     • Major mineral nutrient
     • Bone structure, Nerve transmission, Muscle contraction, Blood clotting, Vascular Control (B.P)
       • Deficiency signs: Tetany (Cramp), Osteoporosis, Hypertension
         • Poor, Children, Pregnant, Elderly, Low Milk intake, Post menopausal @ risk
           • Found in Dairy, Beans, Broccoli, Dried Fruits, Tofu, Molasses, Fortified Foods (Juice)
           • Needed for
             • Growth, Lactation, Kidney/Liver failure, Age, High phosphate dieters
   • Phosphorus
     • - charged O2 containing molecule
     • Part of DNA, RNA, Phospholipids, ATP, Bone
       • Makes Phospolipids water soluble
       • Deficiency Signs: Weakness, No appetite, Muscle pain
         • Preterm infants, Elderly, Excess alcohol, Postmenopausal @ risk
           • Found in Meat, Milk, Eggs, Nuts, Fish, Baked Goods*, Soda Pop
     • Excess = Affect Calcium status & decrease iron absorption
   • Fluoride
     • Very water soluble
     • Part of teeth (contaminant)
       • Makes teeth resistant to dental caries
       • Deficiency signs: Dental caries with poor mouth hygiene
         • Ppl who drink unfluoridated H2O (bottled)/use unfluoridated toothpaste @ risk
     • Found in: public drinking H2O, Toothpaste, Tea, Seafoods
       • Toxicity - discoloration of teeth

3. Vitamins

   • Vitamin D
     • Fat-Soluble
       • Acts as a hormone
     • For: Bone metabolism, Calcium absorption by intestine, Calcium reabsorption by kidney (so not lost in urine)
       • Deficiency signs: Rickets (children knee prob), Osteomalacia (softening of bones)
         • Fat malabsorption (cystic fibrosis, aids), kidney/liver failure, no sunlight, low milk consumption @ risk
           • High toxicity risk (10X RDA)
     • Found in: Sunlight, Fortified MIlk, Egg Yolk, Fish OIl
     • Sunlight turned into active hormone by kidney & liver

4. Relationships between Major Nutrients

   • VIT C needed to make collagen (main proteins)
   • VIT A needed to maintain cells that remodel bone (breakdown & formation)
     • Low Blood Calcium
       • High Dietary Phosphate
       • Low Dietary Calcium
       • Bone breakdown, Activation of VIT D, Increased intestinal absorption of Calcium (active D), - urinary loss of Calcium (active D)
         • Calcium released into blood, bone proteins degraded

5. Calcium Supplements

   • Max 1g/day
     • Over 3g/day = iron deficiency (antacid
       • Avoid amino acid supplements & caffiene
         • Calcium citrate, malate, lactate > carbonate > gluconate > chloride
         • Oyster shells, Dolomite, Bone meal
       • Chelators make calcium water soluble

6. Osteoporosis

   • Loss of bone mineral & protein
     • Bone loses strength
   • Fractures caused by falls
   • Females, Menopause (- estrogen), 35+ y/o
     • Smokers, Alcoholics @ risk
       • Caucasians > Asians > African
     • Weight bearing exercises & + appetite decreases risk