Diet and Health: Diet-Related Diseases

What you'll learn

This revision guide covers all testable content on diet-related diseases for the CXC CSEC Food and Nutrition examination. You will learn the causes, symptoms, prevention, and management of non-communicable diseases linked to poor dietary choices, including obesity, diabetes, cardiovascular diseases, and nutritional deficiency conditions. Understanding these conditions is essential for Paper 01 (multiple choice), Paper 02 (structured and extended response), and the School-Based Assessment.

Key terms and definitions

Obesity — A condition characterized by excessive body fat accumulation, defined as having a Body Mass Index (BMI) of 30 kg/m² or above, resulting from consistent energy intake exceeding energy expenditure.

Type 2 Diabetes Mellitus — A metabolic disorder in which the body cannot properly use or produce sufficient insulin, leading to persistently elevated blood glucose levels, often associated with obesity and poor dietary habits.

Hypertension — Abnormally high blood pressure (140/90 mmHg or above) that increases the risk of heart disease and stroke, frequently linked to excessive sodium intake and obesity.

Cardiovascular Disease (CVD) — A group of disorders affecting the heart and blood vessels, including coronary heart disease, atherosclerosis, and stroke, strongly associated with saturated fat consumption and cholesterol accumulation.

Atherosclerosis — The build-up of fatty deposits (plaques) on artery walls, narrowing blood vessels and restricting blood flow, caused by excessive dietary cholesterol and saturated fats.

Anaemia — A condition where the blood contains insufficient haemoglobin or red blood cells to transport adequate oxygen, commonly caused by iron, folate, or vitamin B12 deficiency.

Dental caries — Tooth decay resulting from bacterial action on sugar in the mouth, producing acids that erode tooth enamel, commonly linked to excessive consumption of sugary foods and beverages.

Malnutrition — A condition resulting from an unbalanced diet, including both undernutrition (insufficient nutrients) and overnutrition (excessive intake leading to obesity and related diseases).

Core concepts

Obesity: Causes, Effects, and Prevention

Obesity occurs when energy intake consistently exceeds energy expenditure over extended periods. In the Caribbean, obesity rates have increased significantly, with regional studies showing that approximately 30-40% of adults in countries like Trinidad and Tobago, Jamaica, and Barbados are obese.

Causes of obesity:

• Excessive consumption of energy-dense foods high in fats and refined sugars
• Increased intake of processed foods and sugar-sweetened beverages (soft drinks popular across the Caribbean)
• Sedentary lifestyles with reduced physical activity
• Genetic predisposition combined with environmental factors
• Psychological factors including emotional eating and stress
• Large portion sizes, particularly of high-calorie fast foods

Health consequences:

• Increased risk of Type 2 diabetes, hypertension, and cardiovascular disease
• Joint problems and osteoarthritis from excess weight on bones
• Increased cancer risk (breast, colon, kidney)
• Respiratory difficulties including sleep apnoea
• Reduced self-esteem and psychological problems
• Reduced life expectancy

Prevention and management:

• Balance energy intake with physical activity levels
• Consume nutrient-dense foods: fruits, vegetables, whole grains, lean proteins
• Limit intake of refined sugars, saturated fats, and processed foods
• Practice portion control using the plate method (½ vegetables, ¼ protein, ¼ complex carbohydrates)
• Engage in at least 150 minutes of moderate physical activity weekly
• Reduce consumption of sugar-sweetened beverages; choose water instead
• Read food labels to make informed choices about energy content

Type 2 Diabetes Mellitus

Type 2 diabetes is increasingly prevalent in the Caribbean, with regional statistics showing that some Caribbean nations have among the highest diabetes rates globally. The condition develops when the body becomes resistant to insulin or cannot produce sufficient insulin to regulate blood glucose effectively.

Causes and risk factors:

• Obesity, particularly abdominal obesity
• Diets high in refined carbohydrates and added sugars
• Insufficient dietary fibre intake
• Physical inactivity
• Family history and genetic factors
• Increasing age (though now affecting younger populations due to lifestyle changes)

Symptoms:

• Excessive thirst and frequent urination
• Increased hunger despite eating
• Unexplained weight loss
• Fatigue and weakness
• Blurred vision
• Slow-healing wounds and frequent infections
• Tingling or numbness in extremities

Dietary management:

• Control total carbohydrate intake and distribute evenly throughout the day
• Choose low glycaemic index (GI) foods: ground provisions like dasheen, breadfruit, and sweet potato rather than white rice
• Increase dietary fibre through whole grains, peas, beans, fruits, and vegetables
• Limit refined sugars and sugar-sweetened beverages completely
• Maintain consistent meal times to regulate blood glucose
• Control portion sizes to manage weight
• Include cinnamon and other spices that may help regulate blood sugar

Prevention strategies:

• Maintain healthy body weight (BMI 18.5-24.9 kg/m²)
• Regular physical activity
• Consume balanced meals with adequate fibre
• Limit processed and refined carbohydrates
• Choose water and unsweetened beverages

Hypertension (High Blood Pressure)

Hypertension affects a significant proportion of Caribbean adults and is a major risk factor for stroke and heart disease. Normal blood pressure is below 120/80 mmHg; readings consistently at or above 140/90 mmHg indicate hypertension.

Causes:

• Excessive sodium (salt) intake, particularly from processed foods and added table salt
• Obesity and excess body weight
• Excessive alcohol consumption
• Diets low in potassium, calcium, and magnesium
• Physical inactivity
• Stress and psychological factors
• Genetic predisposition

Caribbean dietary factors: Many traditional Caribbean cooking methods involve high salt content in preserved meats (salt fish, salt beef), seasonings, and condiments. Increased consumption of imported processed foods has further elevated sodium intake.

Health consequences:

• Increased risk of stroke (cerebrovascular accident)
• Heart attacks and heart failure
• Kidney damage and kidney failure
• Vision problems and retinal damage
• Cognitive impairment

Dietary management and prevention:

• Reduce sodium intake to less than 2,300 mg daily (approximately 1 teaspoon salt)
• Limit processed and packaged foods high in sodium
• Remove salt shaker from the table; use herbs and spices for flavour
• Rinse salt fish thoroughly and soak overnight before cooking
• Follow the DASH diet principles: increased fruits, vegetables, low-fat dairy, whole grains
• Increase potassium intake through bananas, oranges, callaloo, and other green leafy vegetables
• Maintain healthy weight through balanced diet
• Limit alcohol consumption
• Increase physical activity

Cardiovascular Diseases (CVD)

Cardiovascular diseases, including coronary heart disease, atherosclerosis, angina, and myocardial infarction (heart attack), are leading causes of death in the Caribbean region.

Causes:

• Diets high in saturated fats (fatty meats, full-fat dairy, coconut oil, palm oil)
• Excessive trans fats from partially hydrogenated oils in processed foods
• High dietary cholesterol from organ meats and egg yolks in excess
• Obesity and physical inactivity
• Hypertension and diabetes
• Smoking

Atherosclerosis development:

1. Excess dietary cholesterol and saturated fats increase blood cholesterol levels
2. Low-density lipoprotein (LDL) cholesterol deposits on artery walls
3. Fatty plaques form, narrowing arteries and reducing blood flow
4. Blood clots may form on plaques, potentially blocking arteries completely
5. Restricted blood flow to heart causes angina; complete blockage causes heart attack

Dietary prevention and management:

• Reduce saturated fat intake to less than 10% of total energy
• Eliminate trans fats from diet completely
• Choose lean meats (chicken without skin, fish) over fatty cuts
• Increase omega-3 fatty acids from oily fish (tuna, mackerel, sardines)
• Use healthier cooking methods: grilling, baking, steaming instead of frying
• Increase soluble fibre intake to reduce cholesterol absorption (oats, peas, beans, okra)
• Consume plenty of fruits and vegetables rich in antioxidants
• Choose unsaturated fats (olive oil, avocado) in moderation
• Limit dietary cholesterol from organ meats

Iron Deficiency Anaemia

Anaemia is the most common nutritional deficiency globally and affects many Caribbean populations, particularly women of childbearing age, pregnant women, and young children.

Causes:

• Insufficient dietary iron intake
• Poor iron absorption due to inadequate vitamin C
• Excessive consumption of tea and coffee with meals (tannins inhibit iron absorption)
• Blood loss through menstruation or parasitic infections
• Increased iron requirements during pregnancy and growth periods

Symptoms:

• Persistent fatigue and weakness
• Pale skin, nail beds, and conjunctiva
• Shortness of breath
• Dizziness and headaches
• Cold hands and feet
• Poor concentration and reduced work capacity

Dietary management:

• Increase haem iron sources (readily absorbed): liver, red meats, poultry, fish
• Include non-haem iron sources: dark green leafy vegetables (callaloo, spinach), peas, beans, fortified cereals
• Consume vitamin C-rich foods with meals to enhance iron absorption: citrus fruits, tomatoes, peppers
• Avoid tea and coffee with meals
• Cook in cast iron pots to increase iron content of foods
• Consider iron supplementation if prescribed by healthcare provider

Other Diet-Related Conditions

Dental caries:

• Caused by bacteria fermenting sugars to produce acid that erodes tooth enamel
• Prevention: reduce sugar intake, brush teeth regularly, choose water over sugary drinks

Osteoporosis:

• Weakening of bones due to insufficient calcium and vitamin D
• More common in older adults, particularly post-menopausal women
• Prevention: adequate calcium intake (milk, cheese, green leafy vegetables, small fish with bones), vitamin D from sunlight and fortified foods, weight-bearing exercise

Constipation:

• Difficulty passing stools due to insufficient dietary fibre and inadequate fluid intake
• Prevention: increase fibre from whole grains, fruits, vegetables, ground provisions; drink adequate water (8 glasses daily)

Diverticular disease:

• Formation of pouches in colon wall, aggravated by low-fibre diet
• Management: increase dietary fibre gradually, maintain adequate hydration

Worked examples

Example 1: Structured response question (6 marks)

Mrs. Johnson, a 45-year-old office worker, has been diagnosed with Type 2 diabetes. Her doctor has advised dietary changes to help manage her condition.

(a) State THREE symptoms Mrs. Johnson may have experienced before diagnosis. (3 marks)

(b) Suggest THREE dietary modifications Mrs. Johnson should make to manage her diabetes. (3 marks)

Model answer:

(a) Any three symptoms (1 mark each):

• Excessive thirst and frequent urination
• Increased hunger despite eating
• Unexplained weight loss
• Fatigue and weakness
• Blurred vision
• Slow-healing wounds

(b) Three dietary modifications (1 mark each):

• Choose low glycaemic index carbohydrates such as whole grain bread, ground provisions (sweet potato, dasheen) instead of refined carbohydrates like white rice
• Increase dietary fibre intake by consuming more peas, beans, fruits with skin, and vegetables
• Limit or eliminate refined sugars and sugar-sweetened beverages, choosing water instead

Example 2: Extended response question (8 marks)

Cardiovascular disease is a leading cause of death in the Caribbean.

(a) Explain how atherosclerosis develops in the body. (4 marks)

(b) Recommend FOUR dietary changes that can reduce the risk of cardiovascular disease. (4 marks)

Model answer:

(a) Explanation of atherosclerosis development:

• Excessive consumption of saturated fats and cholesterol increases blood cholesterol levels (1 mark)
• Low-density lipoprotein (LDL) cholesterol is deposited on the walls of arteries (1 mark)
• These deposits form fatty plaques that build up over time (1 mark)
• The plaques narrow the arteries, restricting blood flow and potentially leading to blood clots, heart attacks, or strokes (1 mark)

(b) Four dietary changes (1 mark each):

• Reduce intake of saturated fats by choosing lean meats, removing skin from poultry, and limiting use of coconut oil and palm oil
• Increase consumption of oily fish (mackerel, tuna, sardines) at least twice weekly to obtain omega-3 fatty acids
• Consume more soluble fibre from foods like oats, peas, beans, and okra to help reduce cholesterol absorption
• Increase intake of fresh fruits and vegetables to provide antioxidants and reduce risk factors

Example 3: Multiple choice style

Which of the following dietary changes would be MOST effective in reducing high blood pressure?

A. Increasing protein intake B. Reducing sodium intake C. Increasing fat intake D. Reducing calcium intake

Answer: B — Reducing sodium intake is the most effective dietary intervention for lowering blood pressure, as excess sodium causes water retention and increases blood volume, raising pressure on artery walls.

Common mistakes and how to avoid them

• Confusing symptoms with causes: Students often list obesity as a symptom of diabetes rather than a cause. Remember: obesity is a risk factor and cause; symptoms include excessive thirst, frequent urination, and fatigue.

• Vague dietary recommendations: Avoid general statements like "eat healthy" or "exercise more." Be specific: "consume at least 5 servings of fruits and vegetables daily" or "engage in 30 minutes of moderate physical activity 5 times weekly."

• Mixing up types of fats: Clearly distinguish between saturated fats (solid at room temperature, raise cholesterol), unsaturated fats (liquid at room temperature, beneficial in moderation), and trans fats (artificially hydrogenated, should be eliminated).

• Not using Caribbean examples: When questions ask for food recommendations, use regional foods students recognize: callaloo instead of just "green leafy vegetables," ground provisions instead of only "complex carbohydrates," or local fish species like kingfish and snapper.

• Incomplete explanations of processes: When explaining atherosclerosis or how diabetes develops, provide the complete sequence of events, not just isolated facts. Use connective words like "therefore," "as a result," and "consequently."

• Forgetting prevention strategies: Many students focus only on management after disease develops. Examiners equally test prevention through lifestyle and dietary choices before conditions occur.

Exam technique for "Diet and Health: Diet-Related Diseases"

• Command words matter: "State" requires brief factual answers (1-2 words); "Describe" needs more detail about characteristics; "Explain" requires reasoning showing cause and effect; "Suggest" or "Recommend" asks for practical applications with justification.

• Use the mark allocation strategically: If a question is worth 4 marks and asks for dietary recommendations, provide 4 distinct points. Each point should be specific and fully developed. For example, don't just write "eat less fat" (too vague); write "reduce saturated fat intake by choosing grilled fish instead of fried chicken" (specific, practical, complete).

• Link diet to disease mechanisms: When explaining how diet causes disease, show the biological pathway. For CVD: high saturated fat → increased blood cholesterol → LDL deposits on artery walls → plaque formation → narrowed arteries → heart attack risk.

• Practice PEE structure for extended responses: Make your Point, provide Evidence or examples, and Explain the significance. This ensures comprehensive answers that access higher mark bands.

Quick revision summary

Diet-related diseases result from imbalanced nutrient intake over time. Obesity, caused by excess energy consumption, increases risk for Type 2 diabetes, hypertension, and cardiovascular disease. Diabetes management requires controlling carbohydrate intake and choosing low-GI foods. Hypertension prevention focuses on reducing sodium intake and increasing potassium-rich foods. Cardiovascular disease risk decreases with reduced saturated fat, increased fibre, and omega-3 fatty acids. Iron deficiency anaemia requires increased haem and non-haem iron sources with vitamin C for absorption. Prevention through balanced diets rich in fruits, vegetables, whole grains, and lean proteins, combined with physical activity, is essential for all conditions.