Overview
This lecture covers the roles, sources, deficiencies, and interactions of folate (B9) and vitamin B12, emphasizing their importance in DNA synthesis, red blood cell formation, and the nervous system.
Folate (Vitamin B9)
- Folate is a co-enzyme involved in methylation reactions for synthesizing new compounds, especially DNA.
- Folate (natural, inactive) is found in foods; folic acid (synthetic, active) is added to supplements and fortified foods.
- Major functions: DNA synthesis, cell division, red blood cell production, neural tube development, homocysteine breakdown, and neurotransmitter synthesis.
- Key food sources: green leafy vegetables, beans, lentils, and fortified orange juice.
- Folate deficiency can cause neural tube defects (e.g., spina bifida), macrocytic anemia, and increased cardiovascular disease risk.
- Excess folic acid can mask B12 deficiency by correcting blood cell symptoms but not treating neurological issues.
Vitamin B12 (Cobalamin)
- Vitamin B12 activates folate so it can perform DNA and red blood cell synthesis.
- Also required for homocysteine breakdown and development of nerve myelin sheaths.
- Exclusively found in animal foods; some plant products are fortified, but not always sufficiently.
- Absorption requires acidic stomach, R protein, and intrinsic factor; absorption occurs in the ileum.
- Groups at risk: older adults (low stomach acid/intrinsic factor), vegans, people with GI disorders, chronic antacid users, and gastric bypass patients.
- B12 deficiency leads to macrocytic anemia, nerve problems (paresthesia, tingling), and elevated homocysteine.
- Treatment includes B12 injections or sublingual supplements to bypass absorption issues.
Key Terms & Definitions
- Folate — Natural, inactive B9 vitamin from foods, essential for DNA and cell synthesis.
- Folic acid — Synthetic, active form of folate used in supplements and food fortification.
- Homocysteine — Harmful compound; high levels increase cardiovascular risk unless broken down by B vitamins.
- Macrocytic anemia — Large, inefficient red blood cells due to folate or B12 deficiency.
- Intrinsic factor — Protein from the stomach required for B12 absorption.
- Pernicious anemia — Severe anemia caused by lack of intrinsic factor and B12 absorption.
Action Items / Next Steps
- Read textbook sections on folate and B12, focusing on absorption and deficiency.
- Complete mastering quizzes and study guides on water-soluble vitamins.
- Review the Blackboard article on antioxidant status and eye health.
- Create flashcards or a study guide to memorize vitamin functions and sources.