Nutrition material 12

Preserving Bone Mass: Are Supplements the Solution?

Calcium and Vitamin D Intake

• Consume foods and beverages high in calcium and vitamin D to avoid supplements.

• Estimates of vitamin D deficiency range from 19% to 77%, indicating uncertainty about its prevalence as a public health issue.

• Current RDA for vitamin D is not clearly established; the U.S. Preventive Services Task Force finds insufficient evidence for increasing recommendations in non-pregnant adults without symptoms of deficiency.

• Choose vitamin D supplements that provide D3 (cholecalciferol) over D2 (ergocalciferol) for better blood level increases.

• Supplements should be labeled as "purified" and carry the USP Verified Mark.

• Limit vitamin D supplementation to below the UL of 4,000 IU per day.

Key Takeaways

• A diet rich in calcium can eliminate the need for supplements, while vitamin D levels might require supplementation due to limited dietary sources.

• Consult healthcare providers if dietary intake and sun exposure are inadequate, as many safe and effective options exist.

• Maintaining a healthy weight supports proper vitamin D levels.

Critical Thinking Questions

1. Evaluate your personal need for calcium and vitamin D supplementation.

2. Discuss preferences for increasing vitamin D levels: natural foods, fortified foods, supplements, or sun exposure.

Safety and Supplementation Concerns

• Calcium supplements are not routinely tested for lead content; manufacturers must ensure compliance with FDA standards.

• Select supplements labeled as lead-free and purified.

• Recent concerns suggest calcium supplements may increase the risk of myocardial infarction (MI); however, findings from studies are mixed.

• Long-term studies indicate that while supplementation increases bone density, it does not significantly lower fracture risk or may elevate MI risk.

Factors Contributing to Vitamin D Deficiency

• Decreased consumption of vitamin D-fortified milk.

• Increased sun avoidance and use of sunscreen.

• Rising obesity rates, which can alter vitamin D metabolism.

Blood Health and Immunity

Anemia Overview

• Over 30% of the global population is anemic, causing delays in child development and increasing maternal mortality, particularly in pregnancy.

Functions of Blood

• Blood transports nutrients and oxygen, removes metabolic waste, and plays a vital role in immune defense.

• Blood is composed of:

  • Erythrocytes (Red Blood Cells): Transport oxygen; live about four months.

  • Leukocytes (White Blood Cells): Protect against infection; short lifespan, requiring rapid replenishment.

  • Platelets: Aid in clotting; live about one week.

  • Plasma: The fluid component that carries nutrients, hormones, and waste.

Nutrients Essential for Blood Health

• Iron, Zinc, and Copper: Crucial trace minerals for oxygen transport and overall blood functionality.

• Vitamin K: Necessary for blood clotting.

• Vitamins B6, Folate, and B12: Key for red blood cell formation.

Iron Deficiency

Iron Functions

• Iron is essential for hemoglobin and myoglobin, aiding oxygen transport.

• Daily, about 200 billion erythrocytes are produced, requiring approximately 24 mg of iron.

• Iron exists in two forms: Ferrous (Fe2+) and Ferric (Fe3+).

Iron Absorption

• Absorption is affected by dietary iron, stomach acid, and other dietary factors that enhance or inhibit iron uptake.

• Heme iron from animal sources is better absorbed than nonheme iron from plants.

Iron Storage and Excretion

• Iron is mainly stored as ferritin and hemosiderin in the liver and bone marrow.

• Daily iron losses vary from 1.5 mg (men) to 14 mg (women due to menstruation); excretion occurs primarily via the digestive tract.

Dietary Recommendations

• RDA for iron: 8 mg/day (men), 18 mg/day (women aged 19 to 50), and 27 mg/day during pregnancy.

Food Sources

• Rich heme iron sources: meats, fish, poultry.

• Nonheme iron sources: fortified cereals, legumes, leafy greens, where absorption can be aided by vitamin C.

Zinc and Copper in Blood Health

Zinc Functions

• Essential for over 300 enzymes, growth, and reproductive health.

• RDA: 11 mg/day (men) and 8 mg/day (women).

Copper Functions

• Required for iron transport and enzyme activation.

• RDA: 900 µg/day.

• Sources include organ meats, seafood, nuts, and seeds.

Vitamins and Blood Health

Vitamin K

• Essential for blood clotting; found in green leafy vegetables.

Vitamin B6

• Important for heme synthesis.

Folate

• Crucial for red blood cell production; RDA: 400 µg/day (600 µg/day for pregnant women).

Vitamin B12

• Required for DNA synthesis and red blood cell formation; RDA: 2.4 µg/day.

Immune Function

Immune System Overview

• Composed of nonspecific defenses (innate immunity) and specific immune responses (adaptive immunity).

Dietary Influences on the Immune System

• Suboptimal nutrition can lead to weaker immune responses.

• Essential nutrients include vitamins (A, C, D, E) and minerals (iron, zinc, copper) crucial for a healthy immune system.

Summary

• Proper nutrition plays an essential role in maintaining blood health and immune function.

• A balanced intake of vitamins and minerals ensures effective functionality of red blood cells and immune responses.