IAL Edexcel Biology - Cardiovascular Disease (3): Dietary Antioxidants, Cholesterol and Treatments

1.13 Understand the link between dietary antioxidants and the risk of cardiovascular

disease (CVD)

1.18(i) Be able to analyse data on the possible significance for health of bloodcholesterol levels and levels of high-density lipoproteins (HDLs) and low-density lipoproteins (LDLs)

1.18(ii) Know the evidence for a causal relationship between blood cholesterol levels(total cholesterol and LDL cholesterol) and cardiovascular disease (CVD)

1.19 Understand how people use scientific knowledge about the effect of diet, including obesity indicators, such as body mass index and waist-to-hip ratio, exercise and smoking to reduce their risk of coronary heart disease

1.20 Know the benefits and risks of treatments for cardiovascular disease (CVD) (antihypertensives, statins, anticoagulants and platelet inhibitors)

• Also known as ascorbic acid
• Found in fresh fruits and vegetables
• Helps lower the risk of CVD by neutralizing free radicals which causes cell damage include cells in cardiovascular system
• Cooking (or heat) may destroy vitamin C partially or completely
• The vitamin C content in a sample can be tested using DCPIP (vitamin C reduces the blue dye in DCPIP and turns the solution colourless)

• Water-insoluble lipid
• Carried in blood by proteins by forming soluble complexes (lipoproteins)
• 2 types of lipoproteins

Low density lipoprotein (LDL); “bad” cholesterol

• Made from saturated fats, protein, cholesterol
• Binds to cell surface receptors which may become saturated leaving excess LDL in blood
• Associated with the formation of atherosclerosis
• Should be kept a low level

• Made from unsaturated fats, cholesterol and protein
• Helps lower blood cholesterol levels by carrying cholesterol from body tissues to the liver to be broken down
• Can also remove cholesterol from plaques on the arteries
• Should be kept at high level

• Strong correlation between high intake of saturated fats and high blood cholesterol
• Causal link between high blood cholesterol and CVDs (cholesterol helps form plaque)
• LDL and HDL have opposite effects so ratio of LDL to HDL is an important risk indicator for CVD

👇 Study the mechanism and side effects of each treatment for your IAL Edexcel Biology 👇

Diuretics (an antihypertensive)

• Decreases water reabsorption in the kidney tubules and increases volume of urine, thereby lowering blood volume and pressure
• May cause dizziness occasionally, nausea and muscle cramps

Beta blockers (an antihypertensive)

• Block the response of the heart to epinephrine (adrenalin) and causes the heart contractions to become less frequent and powerful
• Potential link with diabetes

ACE inhibitors (an antihypertensive)

• Inhibits the angiotensin converting enzyme (ACE) and thereby the production of angiotensin, which normally causes arterial constriction and increases blood pressure
• May cause cough, dizziness, heart arrhythmia, impaired kidney function

Statins

• Act by inhibiting the liver enzyme which makes cholesterol and thereby lowering blood cholesterol level
• May cause muscle aches, nausea, constipation, diarrhea
• Rare: inflammatory reactions (potentially fatal), and liver failure (potentially fatal)
• May “encourage” people to rely on the drug and not make an effort to eat a healthy diet

Anticoagulants (e.g. warfarin)

• Reduce clot formation
• Risk of uncontrolled bleeding
• Important to control dosage

Platelet inhibitory drugs (e.g. aspirin, clopidogrel)

• Make platelets less “sticky” 
• May irritate stomach lining and cause gastrointestinal side effects (e.g. stomach bleeding)
• Combined drug use may exacerbate the side effects

Want to improve your IAL Edexcel Biology? Check out our study tips here

Time for some vitamin C replenishment!

Written by Vivian | GCE Biology Specialist @ TUTTEE

References:

1. Edexcel AS Biology Revision Guide. Edexcel.