Diet-Related Health Conditions

Osteoporosis and Bone Health

Exam-Standard Phrasing

Examiners look for these exact words: osteoporosis is a skeletal condition where bones lose mineral density, turning thin, porous and brittle, so that they break easily. Knowing that exact trio of adjectives will secure full marks on definition questions.

Peak bone mass is achieved between 30 and 35 years of age, making childhood and adolescence the crucial windows for bone mineralisation. If bone resorption outpaces bone deposition, the internal scaffolding degrades, sharply increasing fracture risk at structural stress points: the hips, wrists and spine. Compression fractures of vertebrae cause loss of height and a stooped posture (kyphosis). Doctors confirm the diagnosis using a DEXA scan, which measures exactly how dense the bone minerals are.

Contributory Risk Factors

• Gender and Hormonal Decline: Risk is highest among women. Once a woman reaches menopause, her oestrogen levels drop sharply. This hormone normally works to slow bone resorption, so when production falls away, skeletal density declines at speed.
• Age and Genetics: Advancing age diminishes osteoblast activity, and a family history indicates an inherited risk.
• Low Body Weight: Having a BMI under 19 kg/m² or experiencing considerable, rapid weight loss reduces mechanical skeletal loading.
• Nutritional Shortfalls: Bone consists of calcium phosphate in a collagen matrix. When dietary intake falls short, the body extracts stored calcium from skeletal tissue to maintain serum levels. Your gut needs vitamin D to produce the calcium-binding protein that pulls calcium into the blood; without it, most dietary calcium passes straight through unabsorbed.
• Physical Inactivity: Sedentary living lacks mechanical stress. Weight-bearing exercise forces the skeleton to work against gravity, stimulating osteoblasts to deposit new bone matrix.
• Lifestyle and Medications: Smoking and excess alcohol directly impair osteoblast function and calcium absorption. Long-term use of corticosteroids and conditions causing intestinal malabsorption (like untreated coeliac disease) severely elevate risk. High dietary sodium and excess caffeine also increase urinary calcium excretion.

Dietary Management and RDAs

For an adult, the daily calcium recommendation sits at 800 mg, but teenagers in active growth phases and post-menopausal women need 1,200 mg every day to counter bone loss. Good dietary calcium comes from milk, hard cheeses, yoghurt, tinned fish eaten with soft bones like sardines, dark green vegetables, and fortified plant drinks. Primary sources of vitamin D include sunlight exposure (April to September in Ireland), oily fish, fortified milks, eggs, and winter supplements. Doctors may prescribe bisphosphonate medications to slow skeletal breakdown.

Coronary Heart Disease and Hypertension

Exam-Standard Phrasing

When fatty deposits called atheroma build up inside coronary arteries and narrow them, the heart muscle is starved of oxygenated blood — that is coronary heart disease (CHD).

Atherosclerosis Mechanism

The disease progresses along a defined biological pathway:

1. Diets loaded with saturated and trans fats push up circulating levels of low-density lipoprotein (LDL) cholesterol in the bloodstream.
2. Excess LDL penetrates the damaged inner lining of the coronary arteries and oxidises.
3. Inflammatory white cells ingest this oxidised lipid, transforming into foam cells that form a fatty streak.
4. Over time, calcium and fibrous tissue join the deposit, producing a hardened plaque called an atheroma (atherosclerosis).
5. Narrowed vessel lumens restrict coronary blood supply, causing angina (ischaemic chest pain during exertion). Should a plaque tear open, a rapid blood clot can choke off the artery completely, triggering a myocardial infarction — a heart attack.

Lipoprotein Transport

Cholesterol is insoluble in water and must travel bound to protein envelopes:

• Low-Density Lipoprotein (LDL): Carries cholesterol away from the liver towards peripheral tissues, but it readily drops surplus fat right into artery walls to build up atheroma.
• High-Density Lipoprotein (HDL): Think of HDL as your vascular sweep-up crew, collecting spare cholesterol off artery walls and tissues before returning it to the liver for breakdown into bile.

Risk Factors

• Modifiable: Diets rich in saturated fat and trans fat, smoking (which damages arterial endothelial cells and lowers HDL), physical inactivity, obesity (notably visceral fat), excess alcohol, and high sodium intake driving hypertension.
• Non-Modifiable: Advancing age, male gender (though women catch up post-menopause as oestrogen levels fall), and a family history of premature cardiovascular events.

Dietary Management and Culinary Techniques

• Swap hard saturated fats like butter and lard for liquid plant oils such as olive or rapeseed oil.
• Aim for two portions of oily fish each week — think salmon, mackerel, or sardines. They provide omega-3 fatty acids, which keep triglycerides down and stop dangerous clots from forming.
• Increase soluble fibre from oats, beans and pulses to bind bile salts in the gut and clear cholesterol.
• Shift towards a Mediterranean eating pattern loaded with vegetables, fresh fruit, nuts, whole grains, and lean cuts of poultry.
• Practical kitchen techniques: grill, bake, steam, poach or use an air fryer; trim visible rind and fat from meats; remove skin from poultry; chill homemade soups and stews to lift off the solidified fat cap before serving.

Dietary Fibre and Bowel Health

Exam-Standard Description

We know dietary fibre, or non-starch polysaccharide (NSP), as the structural scaffolding that reinforces plant cell walls. Because our digestive enzymes cannot break it down, it passes through the alimentary tract largely unaltered. The adult recommended intake is 24–35 g per day.

Fibre Classifications and Biological Actions

• Insoluble Fibre (Cellulose, Hemicellulose, Lignin): This type cannot dissolve in water, so it draws in moisture throughout the colon, expanding to provide physical bulk to food waste. This physical bulk presses against the colon wall, stimulating muscular contractions known as peristalsis. This speeds up transit time, preventing waste stagnation.
• Soluble Fibre (Pectin, Gums, Mucilages): Dissolves in water to produce a viscous gel. This gel delays gastric emptying, flattening postprandial blood glucose curves, and binds bile salts and dietary cholesterol in the gut so they are excreted rather than reabsorbed.

Bowel Disorders Examined by the SEC

• Constipation: Infrequent, hard, dry stools passed with straining, caused by low fibre, insufficient water intake and lack of exercise. Soluble and insoluble fibre with 2 litres of water daily softens and bulks stools.
• Diverticular Disease (Diverticulitis): When stools are small and hard due to low fibre, the colon must generate immense muscular pressure to move them. This high pressure forces the mucosal lining to herniate through weak points in the muscular wall, forming tiny pouches called diverticula. If food debris or bacteria lodge inside, these pockets become inflamed and infected (diverticulitis), causing intense abdominal pain, fever and bleeding.
• Haemorrhoids (Piles): Distended, varicose veins in the anal canal resulting directly from chronic straining during bowel movements caused by dry, unbulked stools.
• Bowel (Colon) Cancer: Second most common cancer in Ireland. Low-fibre diets slow transit times, giving environmental carcinogens extended contact with colon epithelial cells. Diets high in processed red meat elevate risk, while fibre speeds transit and dilutes carcinogens. National screening operates through BowelScreen.

Telling IBD Apart from IBS

IBD encompasses chronic autoimmune conditions causing visible structural lesions. Crohn's disease causes patchy inflammation and deep ulceration across any digestive region from mouth to anus, resulting in malabsorption, diarrhoea and severe weight loss. Ulcerative colitis produces continuous ulceration confined strictly to the colon and rectum. During active IBD flares, patients require a low-residue diet (refined white carbohydrates, lean steamed fish, peeled well-cooked vegetables) to minimise stool bulk and rest the bowel.

Irritable Bowel Syndrome (IBS) is completely different: it is a functional motility disorder where the gut spasms, causing bloating and wild swings between constipation and diarrhoea, yet an endoscope will reveal zero physical inflammation, ulcers, or structural damage.

Coeliac Disease and Food Hypersensitivities

Exam-Standard Description

In coeliac disease, dietary gluten triggers an autoimmune response right along the small intestinal lining, flattening the tiny villi until nutrient uptake grinds to a halt through severe malabsorption.

Gluten is a composite storage protein found in wheat, barley, rye and oats (commercial oats are frequently cross-contaminated in processing mills). When an affected person eats gluten, intestinal antibodies attack the mucosal lining. The microscopic finger-like projections (villi) atrophy, dramatically shrinking the absorptive surface area. Nutrients pass through unabsorbed.

Clinical Presentation

Classic signs include chronic steatorrhoea — pale, foul-smelling stools packed with unabsorbed fat — alongside severe stomach bloating, gas, constant fatigue, and sudden weight loss. Over time, poor absorption sparks secondary deficiencies like iron-deficiency anaemia and fragile bones from missed calcium and vitamin D (osteoporosis). In children, it causes failure to thrive.

Meal Planning Guidelines for Coeliac Disease

1. Cut out all gluten grains entirely: That means wheat, barley, rye, spelt, and standard shop oats. Avoid everyday pasta, regular bread, pies, batters, and items thickened with wheat flour.
2. Rely on naturally gluten-free carbohydrates: Base meals around potatoes, rice, maize (corn), buckwheat, quinoa, millet, pulses, and certified gluten-free oats.
3. Identify certified retail foods: Purchase products carrying the official crossed-grain symbol and verified as gluten-free under EU labelling standards.
4. Audit food ingredient panels for hidden gluten: Screen processed foods for hidden wheat binders, hydrolysed vegetable protein, and malt flavourings in processed sausages, gravies, canned soups, soy sauce, and ready meals.
5. Prevent cross-contamination: In shared domestic kitchens, designate a dedicated toaster, use separate chopping boards, keep spotless preparation surfaces, and never double-dip utensils in shared butter dishes or jam jars.
6. Correct nutritional shortfalls: Offer foods rich in haem iron (lean red meat), vitamin C (peppers, citrus), and calcium (dairy or fortified soya) to replenish stores depleted during active malabsorption.

Food Allergy versus Food Intolerance

• Food Allergy: An abnormal, rapid immune system response to a specific food protein, triggering release of histamine. Reactions hit fast: itchy hives (urticaria), swollen lips and throat, wheezing, and vomiting. Under acute systemic reactions, full anaphylaxis develops rapidly, presenting an immediate threat to life unless countered straight away with an adrenaline auto-injector (EpiPen). Food legislation across Ireland and the EU requires manufacturers to highlight fourteen major allergens clearly on packaging, covering items such as peanuts, tree nuts, milk, eggs, fish, molluscs, crustaceans, soya, and celery.
• Food Intolerance: A non-immunological adverse reaction where the body lacks the capacity to digest or metabolise a specific food component, usually due to an enzyme deficit. A prime example is lactose intolerance, where a deficiency of the intestinal brush-border enzyme lactase leaves milk sugar unhydrolysed. Bacteria ferment this sugar in the colon, causing cramps, flatulence, and osmotic diarrhoea within several hours. It is non-life-threatening and managed with lactose-free dairy products, lactase drops, or plant-based milks.

Diabetes Mellitus and Glycaemic Regulation

Exam-Standard Description

When someone develops diabetes mellitus, their body loses the ability to regulate blood glucose, leaving blood sugar persistently high because the pancreas produces insufficient insulin or target cells become resistant to its action.

Clinical Presentation and Long-Term Complications

Classic symptoms comprise excessive thirst (polydipsia), frequent copious urination (polyuria), marked lethargy, unintended weight loss, and recurring infections (such as thrush). A related condition, gestational diabetes, develops temporarily during pregnancy due to placental hormones counteracting maternal insulin; while resolving post-partum, it signals elevated lifetime risk for type 2 diabetes.

Chronic, poorly managed blood glucose leads to microvascular and macrovascular damage:

• Diabetic Retinopathy: High blood glucose damages the delicate capillary network across the retina, sparking progressive loss of sight and potentially full blindness.
• Diabetic Nephropathy: High blood sugar damages delicate kidney filters (glomeruli), which can end in chronic kidney failure.
• Diabetic Neuropathy: Nerve fibre breakdown causing numbness, paresthesia, and foot ulcers that risk amputation.
• Cardiovascular Disease: Markedly accelerated atheroma formation leading to stroke and heart attacks.

Dietary Management Principles

• Maintain consistent meal timings (three evenly spaced meals) to prevent hypoglycaemic troughs and hyperglycaemic spikes.
• Emphasise low glycaemic index (GI) carbohydrates (porridge oats, brown basmati rice, lentils) that hydrolyse slowly, supplying a sustained glucose curve into the blood.
• Restrict simple sugars and sweet treats, swapping them for artificial sweeteners.
• Restrict saturated fat intake to guard against secondary vascular damage, and maintain 150 minutes of weekly aerobic exercise to enhance cellular insulin sensitivity.

Obesity, Energy Balance, and Eating Disorders

Exam-Standard Description

Medically speaking, obesity describes an excessive accumulation of adipose tissue that endangers health, officially identified whenever an adult's Body Mass Index reaches 30.0 kg/m² or higher.

Anyone scoring between 25.0 and 29.9 kg/m² falls into the overweight category. Beyond BMI, examiners value the measurement of waist circumference, which assesses intra-abdominal visceral fat. A waist measurement exceeding 94 cm in men or 80 cm in women marks a sharp increase in metabolic risk.

Aetiology and Health Consequences

A person develops obesity after staying in a prolonged positive energy balance for too long — taking in far more calories from food and drink than their body burns through basal metabolism and daily movement. Diets dominated by energy-dense, nutrient-poor foods (sweet snacks, deep-fried fast food, sugar-sweetened minerals) easily create a calorie surplus. Sedentary domestic and work routines suppress expenditure.

The physical strain affects nearly every organ. It sharply drives up the chance of coronary heart disease and type 2 diabetes, while excess weight grinds down joints in osteoarthritis. Carrying excess adipose tissue also drives complications such as obstructive sleep apnoea, non-alcoholic fatty liver disease, gallstones, and higher incidence rates of bowel, uterine, and breast cancers.

Weight Management Guidelines

Weight loss should follow a safe, gradual reduction of 0.5 kg to 1 kg per week, achieved by generating a moderate energy deficit (cutting 500–600 kcal daily). This preserves lean skeletal muscle tissue and avoids metabolic down-regulation seen in crash diets. Adults must combine diet with at least 30 minutes of moderate activity 5 days a week.

Eating Disorders

• Anorexia Nervosa: A severe psychiatric disorder in which an individual strictly curtails energy intake due to an irrational fear of weight gain, rooted in deeply distorted body perception. The toll on the body is devastating: extreme emaciation, periods stopping completely (amenorrhoea), hypothermia, brittle bones, dangerous electrolyte imbalances, and irregular heartbeats (arrhythmias).
• Bulimia Nervosa: Characterised by recurrent episodes of uncontrolled binge eating followed by compensatory purging behaviours (self-induced vomiting, abuse of laxatives, or periods of starvation). Physical complications include severe dental enamel erosion from gastric hydrochloric acid, persistent oesophagitis, chronic sore throat, dehydration, and dangerous potassium imbalances. Support services operate nationally through organisations like Bodywhys.

Nutritional Deficiencies, Anaemia, and Oral Pathology

Micronutrient Deficiency Disease Profile

The Leaving Certificate frequently asks for direct pairings between clinical deficiency conditions and specific micronutrients:

Iron-Deficiency Anaemia

When blood haemoglobin falls under normal physiological levels, iron-deficiency anaemia takes hold, leaving red blood cells unable to transport sufficient oxygen throughout the body. Symptoms comprise persistent fatigue, pallor, exertional breathlessness, dizziness, headaches, brittle nails (koilonychia), and poor concentration.

Common causes include inadequate dietary intake, rapid growth bursts in adolescence, heavy menstrual blood loss in teenage girls, increased demands during pregnancy, or intestinal malabsorption.

Management guidelines:

• Consume rich sources of haem iron (ferrous iron), which is bioavailable and easily absorbed: liver, red meat, kidney, black pudding, and sardines.
• Ingest non-haem iron (ferric iron): dark green leafy vegetables (kale, spinach), pulses, wholegrain cereals, and dried fruit.
• Pair non-haem iron foods with vitamin C (ascorbic acid) at the same meal. Vitamin C chemically reduces non-haem ferric iron ($Fe^{3+}$) to the soluble ferrous state ($Fe^{2+}$), dramatically boosting gut absorption.
• Do not drink tea or coffee alongside meals: the tannins bind to iron and form insoluble iron-tannate complexes. Avoid excessive raw bran supplements as phytic acid (phytates) blocks iron uptake.

Dental Disease: Caries and Periodontitis

Dental caries is the localised dissolution of enamel and dentine by microbial action. The main trouble begins with dental plaque, that sticky coating formed from saliva proteins, trapped food particles, and mouth bacteria like Streptococcus mutans.

When refined carbohydrates (particularly sucrose) are consumed, plaque bacteria ferment these simple sugars, releasing organic acids (mainly lactic acid). Each sugar exposure sparks an acid attack lasting about 20 minutes, during which oral pH drops below the critical threshold of 5.5. At this acidity, calcium and phosphate dissolve out of the enamel (demineralisation).

Between snacks, alkaline saliva neutralises the acids and remineralises the enamel. However, frequent snacking causes demineralisation to outpace repair, culminating in an irreversible cavity. Fluoride (supplied via toothpaste and municipal fluoridated tap water) swaps into enamel to produce fluorapatite, which resists acid attacks.

Neglected plaque hardens with minerals into tartar (calculus), irritating gingival margins to provoke gingivitis (swollen, bleeding gums). If unmanaged, this progresses into periodontitis, where inflammation destroys the periodontal ligament and alveolar bone, ultimately causing tooth loss.

Dietary Reference Figures and Master Revision Grid

Official Irish Healthy Eating Guidelines (Department of Health / safefood)

• Total Fat Intake: No more than 35% of total dietary energy.
• Saturated Fat Intake: Less than 10% of total dietary energy; industrial trans fats kept as low as possible.
• Free Sugars: Less than 10% of daily energy intake (aiming below 5% for added health benefits).
• Salt Intake: Maximum ceiling of 6 g per day for an adult (equivalent to 2.4 g of sodium).
• Dietary Fibre: Target intake of 24–35 g daily for adults.
• Fruit and Vegetables: At least 5 to 7 servings per day from the base shelf of the Food Pyramid.
• Physical Activity: Irish health guidelines recommend that adults accumulate at least 30 minutes of moderate exercise five days each week, while school-age children need an hour daily.

Master Revision Summary: Diet-Related Conditions

Key terms

Osteoporosis

A skeletal condition in which bones lose mineral density and become thin, porous and brittle, so that they break easily.

Atheroma

A fatty deposit containing cholesterol, calcium, and fibrous tissue that accumulates within arterial walls, causing atherosclerosis.

Low-Density Lipoprotein (LDL)

A lipoprotein carrier that transports cholesterol from the liver to peripheral tissues, capable of depositing cholesterol directly into artery walls.

High-Density Lipoprotein (HDL)

A protective lipoprotein carrier that gathers excess cholesterol from artery walls and tissues, returning it to the liver for excretion.

Peristalsis

The wave-like muscular contractions of the gastrointestinal tract that push ingested food and digestive waste forward.

Insoluble Fibre

Non-starch polysaccharide (such as cellulose and lignin) that absorbs water to add physical bulk to digested waste and speed up peristalsis.

Soluble Fibre

Non-starch polysaccharide (such as pectin and beta-glucan) that dissolves in water to form a gel, binding cholesterol and slowing glucose release.

Coeliac Disease

An autoimmune disorder in which the ingestion of gluten triggers immune-mediated destruction and flattening of the intestinal villi, causing malabsorption.

Gluten

A structural protein found in wheat, barley, rye, and standard oats that causes small intestinal damage in individuals with coeliac disease.

Insulin Resistance

A pathological state in which muscle, fat, and liver cells fail to respond effectively to circulating insulin, characteristic of type 2 diabetes.

Low-Residue Diet

A medical meal plan restricting fibre and indigestible food components to minimise stool volume and rest the intestine during acute inflammatory bowel flares.

Anaphylaxis

A severe, rapid, and potentially life-threatening systemic immune response to an allergen, causing throat swelling, respiratory distress, and shock.

Demineralisation

The chemical process wherein organic acids produced by plaque bacteria dissolve calcium and phosphate ions from dental enamel at a pH below 5.5.

Haem Iron

Ferrous iron ($Fe^{2+}$) sourced from animal haemoglobin and myoglobin, which is highly bioavailable and easily absorbed by the human intestine.