Calcium and Bone Health Quiz

Nutrients for Bone Health

• Bones are made of mineral crystals and protein (collagen).
• Mineral crystals provide strength.
• Protein provides flexibility.
• Two types of bones: cortical and trabecular.
• Blood vessels and nerves run through the center of bones.
• Bone health is defined by bone mineral density (how tightly mineral crystals are packed into the protein matrix).
• Bones are metabolically active, constantly being broken down and rebuilt by osteoclasts and osteoblasts.
• Bone growth in length occurs from conception to teenage years, and density may continue to accrue into young adulthood.
• Bone lengthening usually stops around age 14 for females and 17 for males.
• Bone loss is influenced by genetics, nutrition, and physical activity.

Factors Affecting Bone Health

• Genetics
• Weight-bearing activity
• Alcohol consumption
• Animal protein consumption
• Smoking
• Adequate nutrient intake
• Sleep
• Body weight

Nutrition for Bone Health

• Collagen is supported by protein and Vitamin C.
• Mineral crystals are supported by Calcium, Phosphorus, Magnesium, Fluoride, Vitamin D, and Vitamin K.

Calcium in Bones

• Calcium is the most abundant mineral in the body.
• Approximately 99% of calcium is stored in bones and teeth.
• Functions as an integral part of bones, working with phosphorus.
• Bones release calcium into body fluids when blood calcium levels decrease.
• Bone mineral formation and dissolution are constantly occurring.
• Hydroxyapatite is the chief crystal in bone formation.
• Fluorapatite, a fluoride compound, resists bone dissolution to maintain bone integrity.
• Only ~1% of calcium in the body is found in body fluids.
• Functions in body fluids include regulating ion transport across cell membranes, supporting muscle contraction, and aiding in hormone, enzyme, and neurotransmitter secretion. Calcium also helps maintain normal blood pressure and is essential for blood clotting.

Calcium and Disease Prevention

• Calcium intake may help protect against hypertension (HTN).
• Research suggests a potential protective relationship between calcium intake and diseases like diabetes, cholesterol levels, colon cancer, and osteoporosis.

Calcium Balance

• Calcium regulation involves the kidneys, intestines, and bones.
• Calcitonin and parathyroid hormone, along with vitamin D, also help regulate calcium levels.
• High blood calcium can lead to calcium rigor.
• Low blood calcium can lead to calcium tetany.

Calcium Absorption

• Adults absorb ~30% of ingested calcium.
• Children/teens absorb ~50-60% of ingested calcium.
• Absorption can adjust based on need (e.g., pregnancy).
• Factors that enhance absorption include stomach acid and vitamin D.
• Factors that inhibit absorption include lack of stomach acid, vitamin D deficiency, high phosphorus intake, phytates (in seeds, nuts, grains), and oxalates (in beet greens, rhubarb, spinach, sweet potatoes).

Calcium Deficiency

• Inadequate calcium intake prevents development of peak bone mass and density.
• Osteoporosis is an adult bone loss condition characterized by brittle, fragile bones, increasing fracture risk.
• It's often silent and not easily detected for some time.

Excess Calcium

• Excessive calcium intake from supplements may negatively affect kidneys.
• Kidney stones are associated with calcium accumulation in the kidneys.
• Other contributing factors can include excess oxalates, phosphates, dehydration, and interference with other mineral absorption.

Calcium Recommendations

• Recommended Daily Allowance (RDA) for calcium varies by age and sex.

Calcium Sources

• Good sources include milk and milk products, vegetables (like rutabaga, broccoli, bok choy, and kale), small fish with bones, almonds, calcium-fortified foods (like plant-based milk, tofu, and OJ), and supplements.

Diet-Related Health Claims

• A healthy diet with adequate calcium and vitamin D, along with regular physical activity (PA), may help achieve strong bones and reduce osteoporosis risk.
• Vitamin D aids in calcium and phosphorus absorption and use in the body.

Phosphorus

• Phosphorus is the second most abundant mineral in the body, with ~85% combined with calcium in hydroxyapatite crystals.
• ~15% is in soft tissues, such as muscles and kidneys.
• Functions as part of genetic material, cell membranes (especially phospholipids), and energy transfer.

Phosphorus: Deficiency and Sources

• Deficiency is rare, but if present, symptoms may include bone and muscle weakness.
• Excess phosphorus can cause calcium excretion and kidney calcification.
• Good sources include animal protein, cottage cheese, salmon, milk, steak, and navy beans.

Vitamin D

• The body can synthesize vitamin D through sun exposure.
• 7-dehydrocholesterol in the skin absorbs UV light and converts to an inactive vitamin D3 precursor absorbed by the blood.
• The liver and kidneys convert this precursor into the active 1,25-hydroxy vit D3 form.
• Good sources include fortified milk, salmon, shrimp, and fortified soy beverages.

Factors Affecting Sun Exposure

• Factors influencing sun exposure include air pollution (clouds, smog, smoke), buildings, window glass, window screens, clothing colors, lifestyle choices (homebound, shift work), skin pigmentation, seasonality, sunscreen use, time of day, and geographic location.

Vitamin D: Functions and Deficiency

• Vitamin D helps absorb dietary calcium and phosphorus in the digestive tract, kidneys, and skeleton, maintaining bone integrity.
• Vitamin D acts as a hormone and raises blood calcium levels when dietary calcium is insufficient.
• Vitamin D affects bone and tooth health.
• Deficiency is generally rare but can result in osteomalacia/Rickets.

Vitamin D: Excess and Sources

• Taking doses that are 5x the recommended daily intake can cause toxicity; problems with over-supplementation and/or wrong fortification doses, can cause loss of appetite, nausea and vomiting, psychological depression, and increased blood calcium leading to calcium deposits in the heart, arteries, kidneys, brain, and bones.
• Vitamin D is naturally found in eggs, fatty fish (e.g. salmon, sardines, mackerel), and fortified milk.
• Recommendations and sources exist for plant-based diets.

Magnesium

• Over half of the body's magnesium is stored in bones.
• Almost all remaining magnesium is in muscle and soft tissues, except ~1% in extracellular fluids.
• Functions include releasing energy, influencing calcium metabolism and vitamin D/K metabolism, and supporting normal muscle contraction and relaxation, nerve transmission and maintaining blood pressure by assisting in calcium regulation.
• Magnesium help hold calcium in the enamel of teeth.

Magnesium: Sources, Deficiency, and Excess

• Good magnesium sources include hard water, legumes, seeds (like pumpkin seeds), nuts, whole grains, leafy green vegetables, and seafood.
• Deficiency symptoms may include weakness and muscle spasms (potentially fatal in the heart), convulsions, hallucinations, loss of appetite, and confusion.
• Excess intake, often from supplements or antacids, may cause diarrhea, dehydration, and acid-base imbalances.

Fluoride

• Fluoride helps form more decay-resistant hydroxyapatite in teeth and bones.
• Fluoride acts directly on bacteria in dental plaque, slowing metabolism and reducing acid production.
• Good sources of fluoride include fluoridated tap water, seafood (varying concentrations).

Fluoride: Deficiency, Excess, and Recommendations

• Deficiency in fluoride can lead to tooth decay and dental caries.
• Excess fluoride can cause fluorosis—irreversible discoloration of the teeth.
• Recommendations for fluoride intake vary by age.

Vitamin K

• Vitamin K plays a role in bone health.
• It's necessary for synthesizing proteins needed in bone formation, particularly osteocalcin.
• Adequate vitamin K helps decrease bone turnover and prevent fractures, working alongside Vitamin D and Calcium to promote proper bone formation.

Osteoporosis & Calcium Highlights

• Osteoporosis, a condition involving brittle, fragile bones, is significantly associated with insufficient calcium intake and decreased bone mineral density.

Development of Osteoporosis

• The incidence of osteoporotic fractures is significant, affecting 1 in 3 women and 1 in 5 men during their lifetime.
• Healthcare systems bear a significant burden due to repair and hospital stay costs.

Risk Factors and Protective Factors for Osteoporosis

• Non-modifiable factors include age, gender, ethnicity, and maternal history, while modifiable factors involve lifestyle, such as physical activity, calcium/vitamin D intake, smoking, and body weight.

Age and Bone Calcium

• Bone mass typically decreases with age, particularly after menopause in women.

Gender and Hormones

• Sex hormones play a crucial role in bone turnover, particularly estrogen in women, with its decline during menopause presenting as a risk factor.
• Men also experience lower bone mass with age, potentially relating to testosterone levels.

Other Contributing Factors

• Genetic predisposition and environmental factors affect bone mass and rate of loss later in life.
• Physical activity, especially weight-bearing exercises, strengthens bones and increases density.
• Body weight and weight loss, along with smoking and alcohol use, can affect bone density.

Bone Growth Goals

• Different stages of life (childhood, adolescence, adulthood) have different recommendations for maintaining and/or growing bone mass/density.
• This relates to consumption habits of critical vitamins and minerals like Ca, Vitamin D, and weight-bearing activities.

Calcium Supplements

• If dietary sources for sufficient calcium, consult with a healthcare professional to avoid exceeding the upper limit (UL) or suffering from excess in the body.
• Multivitamins may have some levels of calcium, but avoid mixing with other supplement or foods high in iron, as they may contain interfering components that lead to poor absorption.

This quiz explores the essential role of calcium in maintaining blood pressure, bone health, and its absorption in the body. It also delves into dietary recommendations and the impact of vitamin D and magnesium on skeletal health. Test your knowledge on these important topics related to nutrition and bone density.