Edexcel A Level (IAL) Biology -1.13 Dietary Antioxidants & CVD- Study Notes- New Syllabus

Understanding the Link Between Dietary Antioxidants and Cardiovascular Disease (CVD)

🌱 Introduction

CVD often begins with damage to the inner lining (endothelium) of arteries.
This damage is worsened by free radicals – unstable molecules that attack cell membranes and DNA.
Antioxidants in our diet protect the body from these free radicals, helping lower the risk of atherosclerosis and CVD.

⚛️ What Are Free Radicals?

• Free radicals = atoms or molecules with unpaired electrons.
• Formed naturally during metabolism (respiration) or from pollution, smoking, radiation.
• Because they are unstable, they oxidize (damage) cell components such as:
  • Lipids in cell membranes
  • Proteins
  • DNA
  • Endothelial cells of blood vessels

Think: “Free radicals = rust for your arteries.”

🍊 What Are Antioxidants?

Antioxidants are molecules that neutralize free radicals by donating electrons without becoming unstable themselves.
This prevents oxidative damage to cells and tissues.

🧩 Major Dietary Antioxidants

❤️ How Antioxidants Reduce CVD Risk

• Protect Endothelium: Prevent oxidation of arterial lining → less endothelial dysfunction.
• Reduce LDL Oxidation: Stops oxidized LDL from sticking → slows plaque formation.
• Prevent Inflammation: Free radicals trigger inflammation; antioxidants lower it → arteries stay flexible.
• Improve HDL Function: Enhances HDL → better cholesterol removal from arteries.

📊 Summary Table

⚡ Quick Recap 
Key Idea: “Free radicals cause oxidation → antioxidants stop oxidation → healthier arteries.”
Good Antioxidant Sources: Citrus fruits, Berries, Nuts, Green tea, Leafy greens
Simple Rule: More antioxidants = less oxidation = lower CVD risk.