2023 CCEA AS-Level Nutrition and Food Science 3310 模拟试题及答案详解

Because energy requirements vary continuously between individuals (unlike most other nutrients, where a Reference Nutrient Intake set high enough to cover most of the population is used), energy is instead expressed using an Estimated Average Requirement (EAR), which represents the average energy need of a group. This avoids setting a figure that would systematically be too high for most individuals and risk encouraging overconsumption. Final answer: Estimated Average Requirement (EAR).

[1] for Estimated Average Requirement / EAR.

Vitamin D is unusual among vitamins in that it can be synthesised in the skin through the action of ultraviolet (UVB) light on a cholesterol-derived precursor, as well as being obtained from the diet. Final answer: vitamin D.

[1] for vitamin D.

Dehydration occurs when fluid losses are not adequately replaced. Even mild dehydration can reduce physical performance (e.g. reduced endurance, increased fatigue) and cognitive performance (e.g. reduced concentration, headache), and more severe dehydration can affect blood volume and thermoregulation. Final answer: reduced physical/cognitive performance (e.g. headache, fatigue, reduced concentration).

[1] for any valid effect of dehydration, e.g. headache, fatigue, reduced concentration/cognitive performance, reduced physical performance, dizziness.

An essential fatty acid is a fatty acid that the human body is unable to synthesise (or cannot synthesise in sufficient quantities) and which must therefore be obtained directly from the diet. The main essential fatty acids are the omega-3 and omega-6 polyunsaturated fatty acids, which are needed for normal cell membrane structure and function. Final answer: a fatty acid the body cannot make itself and must obtain from food, e.g. omega-3/omega-6 fatty acids.

[1] correctly states the fatty acid cannot be made by the body/must come from the diet; [1] a valid named example given (omega-3 and/or omega-6).

Intrinsic sugars are sugars that are contained within the cellular structure of a food, such as the sugar present within the intact cells of whole fruit and vegetables. Extrinsic sugars are sugars that are not held within a food's cell structure, for example sugars in fruit juice (where the cell structure has been broken down), honey, or sugar added to food and drink. This distinction matters because extrinsic sugars (particularly non-milk extrinsic sugars) are more strongly associated with dental caries and are the target of public health advice to reduce free sugar intake. Final answer: intrinsic sugars are contained within a food's cell structure (e.g. whole fruit); extrinsic sugars are not (e.g. fruit juice, added sugar).

[1] correct definition of intrinsic sugars, with a valid example; [1] correct definition of extrinsic sugars, with a valid example.

Calcium has several important functions in the body. The majority of the body's calcium is used for the mineralisation (hardening) of bones and teeth, giving them strength and rigidity. Calcium is also essential for blood clotting, and additionally plays roles in muscle contraction and nerve transmission. Final answer: bone/tooth mineralisation and blood clotting.

[1] mark for each valid function of calcium, to a maximum of 2. Accept: bone/tooth mineralisation, blood clotting, muscle contraction, nerve transmission.

Weaning is the gradual process, usually starting at around six months of age, of introducing solid foods into an infant's diet in addition to breast milk or infant formula, progressively increasing the variety and texture of foods offered until the infant is eating a varied diet similar to the rest of the family. Final answer: the gradual introduction of solid foods alongside milk feeds, moving an infant towards a varied family diet.

[1] correctly identifies weaning as the introduction of solid food to an infant's diet; [1] correctly identifies this as a gradual process occurring alongside/in addition to milk feeds, moving towards a varied diet.

Biological value (BV) is a measure used to describe the quality of a dietary protein, based on the proportion of protein absorbed from a food that is then retained by the body for processes such as growth and tissue maintenance, rather than being excreted. It reflects how closely the balance of indispensable (essential) amino acids in that protein matches the balance the human body actually requires. A protein containing all the indispensable amino acids in approximately the right proportions, such as egg or meat protein, has a high biological value. A protein that is low in, or lacking, one or more indispensable amino acids (the 'limiting amino acid'), as is common in many single plant protein sources, has a lower biological value. Final answer: biological value measures the proportion of absorbed protein retained by the body, reflecting how well its indispensable amino acid balance matches human needs.

[1] correctly defines biological value in terms of the proportion of absorbed protein retained/used by the body; [1] correctly links this to the balance/profile of indispensable amino acids in the protein; [1] correctly distinguishes a high BV protein (e.g. animal protein, all indispensable amino acids present in the right proportions) from a low BV protein (e.g. limited in one or more indispensable amino acids).

Vitamin C acts as an antioxidant in the body, helping to protect cells from damage caused by free radicals. It is also required for the synthesis of collagen, the main structural protein in connective tissue, which is important for skin, blood vessels, and wound healing. In addition, vitamin C enhances the absorption of non-haem (plant-derived) iron in the small intestine by converting it into a more easily absorbed form. Final answer: vitamin C acts as an antioxidant, is needed for collagen synthesis, and enhances non-haem iron absorption.

[1] mark for each correctly outlined function of vitamin C, to a maximum of 3. Accept: antioxidant function; collagen synthesis (connective tissue/wound healing); enhances non-haem iron absorption; supports immune function.

Iron is a key component of haemoglobin, the protein in red blood cells that binds and transports oxygen from the lungs to body tissues. Iron is also a component of myoglobin, a similar protein found in muscle cells that stores oxygen for use during muscular activity. In addition, iron is a cofactor for a number of enzymes involved in energy release from food within cells. Final answer: iron is needed for haemoglobin (oxygen transport), myoglobin (oxygen storage in muscle), and enzymes involved in energy release.

[1] mark for each correctly outlined function of iron, to a maximum of 3. Accept: component of haemoglobin/oxygen transport; component of myoglobin/oxygen storage in muscle; cofactor for enzymes/energy release; role in immune function.

Essential fatty acids (omega-3 and omega-6) are important structural components of cell membranes, affecting membrane fluidity and function throughout the body. They also act as precursors for eicosanoids, such as prostaglandins, which are signalling molecules involved in regulating processes including inflammation and blood clotting. Certain essential fatty acids, particularly omega-3 fatty acids, are also important for the development of the brain and the retina, especially during infancy. A diet deficient in essential fatty acids can therefore lead to physiological consequences including dry, scaly skin (due to disrupted cell membrane and skin barrier function), impaired growth and development (particularly in infants and children), and impaired immune function, since cell membrane integrity and eicosanoid signalling are both important for a normal immune response. Final answer: essential fatty acid deficiency disrupts cell membrane structure and eicosanoid production, leading to skin problems, impaired growth/development, and impaired immune function.

[1] essential fatty acids' role in cell membrane structure/function; [1] essential fatty acids as precursors for eicosanoids/prostaglandins regulating processes such as inflammation/blood clotting; [1] a valid physiological consequence of deficiency (e.g. dry/scaly skin, or impaired brain/visual development); [1] a further valid, distinct consequence of deficiency (e.g. impaired growth or impaired immune function).

Several physiological changes occur with ageing that affect nutrient requirements. Older adults typically experience a reduction in lean body mass (muscle tissue), which lowers their basal metabolic rate (BMR) and therefore reduces their overall energy requirement compared with earlier adulthood, even though requirements for some micronutrients remain similar or increase. Reduced secretion of stomach acid is common in older adults, which can impair the absorption of vitamin B12 (which needs an acidic environment to be released from food), as well as iron and calcium. The skin becomes less efficient at synthesising vitamin D from sunlight with age, and older adults may also have reduced sunlight exposure due to lower mobility, increasing the risk of low vitamin D status. Finally, a reduced sense of taste and smell, and reduced appetite, can lower overall food intake, increasing the risk of inadequate intake of energy and a range of nutrients. Final answer: reduced BMR (lower energy needs), reduced stomach acid (impairing B12/iron/calcium absorption), reduced vitamin D synthesis, and reduced appetite together change older adults' nutrient requirements.

[1] reduced lean body mass/BMR lowering energy requirements; [1] reduced stomach acid secretion impairing absorption of a named nutrient (e.g. vitamin B12, iron or calcium); [1] reduced vitamin D synthesis in the skin/reduced sunlight exposure; [1] reduced taste/smell/appetite reducing overall food intake, or another valid, distinct physiological change.

During pregnancy, nutrient requirements increase to support the rapid growth and development of the foetus, including cell division, tissue formation and, in later pregnancy, significant weight gain. Requirements also increase to support the growth of the placenta, which supplies the foetus with nutrients and oxygen, and to support the substantial increase in the mother's own blood volume and tissue, including growth of the uterus and breast tissue in preparation for breastfeeding. Because most foetal growth occurs in the second half of pregnancy, the increase in energy requirement is concentrated mainly in the third trimester rather than being spread evenly throughout pregnancy. Final answer: nutrient/energy needs rise to support foetal growth, placental growth, increased maternal blood volume/tissue, and preparation for lactation, with energy needs increasing mainly in the third trimester.

[1] correctly links increased requirements to foetal growth and development; [1] correctly links increased requirements to growth of the placenta and/or increased maternal blood volume/tissue; [1] correctly links increased requirements to preparation for lactation; [1] correctly notes that the increase in energy requirement is concentrated in the third trimester rather than evenly spread through pregnancy.

Non-starch polysaccharide (NSP), commonly referred to as dietary fibre, cannot be broken down by human digestive enzymes, so it passes through the small intestine largely undigested and reaches the large intestine mostly intact. Within the digestive tract, NSP adds bulk to the contents of the gut and, in the case of soluble NSP, holds water, softening the stool. This increased bulk stimulates peristalsis, the muscular contractions of the intestinal wall, helping to move waste material through the digestive system more efficiently and helping to prevent constipation. Final answer: NSP resists digestion, adding bulk and holding water in the gut, which stimulates peristalsis and helps prevent constipation.

[1] NSP is not digested by human enzymes, passing largely intact through the gut; [1] NSP adds bulk to gut contents and/or holds water; [1] this stimulates peristalsis, correctly linked to preventing constipation/aiding waste movement.

Vitamin A has several important functions in the body. It is a component of rhodopsin, the light-sensitive pigment in the retina that is essential for vision in low light conditions. Vitamin A also supports the normal growth and differentiation of epithelial cells, which form the surface linings of structures such as the skin, respiratory tract and gut, helping to maintain these tissues as an effective barrier against infection. It additionally supports normal functioning of the immune system. A deficiency of vitamin A initially causes night blindness (difficulty seeing in low light), and if severe or prolonged can progress to xerophthalmia, a condition involving drying and damage to the cornea that can result in permanent blindness; deficiency also increases susceptibility to infections, due to both impaired epithelial barrier function and impaired immune function. Because vitamin A is fat-soluble, it can be stored in the liver, and excess intake (most commonly from supplements or foods very high in preformed vitamin A, such as liver) can build up to toxic levels, causing liver damage; excess vitamin A intake during pregnancy is also teratogenic, meaning it can cause birth defects in the developing foetus, which is why pregnant women are typically advised to avoid liver and high-dose vitamin A supplements. Final answer: vitamin A supports vision, epithelial cell health and immune function; deficiency causes night blindness/xerophthalmia and increased infection risk; excess can cause liver damage and is teratogenic in pregnancy.

[1] function: component of rhodopsin/role in vision in low light; [1] function: growth/differentiation of epithelial cells; [1] function: role in immune function; [1] deficiency: night blindness and/or xerophthalmia correctly described; [1] deficiency: increased susceptibility to infection; [1] excess: liver damage and/or teratogenic effect in pregnancy correctly described. Maximum 6 marks.

Comparing the woman's intake with her RNI: her iron intake of 9.5 mg is considerably below her RNI of 14.8 mg (a shortfall of 5.3 mg, around 64% of her RNI), which suggests her habitual iron intake may be inadequate and could put her at risk of iron deficiency over time. In contrast, her calcium intake of 750 mg is above her RNI of 700 mg, suggesting her calcium intake is adequate. To improve her diet, she could increase her consumption of iron-rich foods, such as red meat, pulses or fortified cereals, ideally eaten alongside a source of vitamin C (such as citrus fruit or peppers), since vitamin C enhances the absorption of non-haem iron from plant sources. Final answer: iron intake is inadequate (below RNI) and should be increased, ideally with a vitamin C source to aid absorption; calcium intake is adequate (above RNI).

[1] correctly identifies iron intake is below the RNI/inadequate; [1] correct comparison/reasoning using the given figures (e.g. calculates or states the shortfall); [1] correctly identifies calcium intake is above the RNI/adequate; [1] a valid, specific suggested dietary change to increase iron intake (e.g. naming an iron-rich food); [1] correctly links the suggestion to enhancing absorption (e.g. combining with a vitamin C source), or another valid distinct improvement; [1] for a clear, well-reasoned overall comment drawing on both minerals' data. Maximum 6 marks.

At each age shown, the infant's weight is below the 50th centile: 5.8 kg versus 6.4 kg at 3 months (a difference of 0.6 kg), 7.6 kg versus 7.9 kg at 6 months (a difference of 0.3 kg), and 8.9 kg versus 9.2 kg at 9 months (a difference of 0.3 kg). This shows the infant has consistently tracked below the average weight for their age, but the size of the gap has narrowed between 3 and 6 months and then remained stable between 6 and 9 months, suggesting the infant is not falling progressively further behind and may be showing some catch-up growth rather than a worsening pattern. A possible dietary reason for an infant tracking below the 50th centile, particularly if the gap was larger in early infancy, could be a delayed start to weaning or introduction of solid foods that were not sufficiently energy-dense, providing less energy than needed to fully match the average growth trajectory; the narrowing gap may reflect an improvement in energy-dense food intake as weaning progressed. Final answer: the infant is consistently below the 50th centile but the shortfall has narrowed and stabilised, possibly reflecting an initially low-energy weaning diet that has since improved.

[1] correctly identifies the infant is below the 50th centile at all three ages; [1] correctly calculates/compares the size of the gap at each age (0.6 kg, 0.3 kg, 0.3 kg); [1] correctly identifies that the gap has narrowed/growth pattern is not worsening; [1] a valid, plausible dietary reason suggested (e.g. delayed weaning or insufficiently energy-dense weaning foods); [1] correctly links the suggested reason to the data pattern described (e.g. improvement over time); [1] for a clear, well-reasoned overall comment. Maximum 6 marks.

Protein has several important functions in the body. It is needed for the growth and repair of body tissue, forming structural components such as muscle and collagen. Protein is also used to synthesise enzymes, which catalyse metabolic reactions, and hormones, such as insulin. It is a component of antibodies, supporting the immune system's ability to fight infection. Although not its primary role, protein can also act as a secondary source of energy if carbohydrate and fat intake are inadequate, though this uses protein that would otherwise be available for growth and repair. Severe protein-energy deficiency in a young child causes a condition known as kwashiorkor, characterised by oedema (swelling, particularly noticeable in the abdomen and limbs, caused by low blood protein levels reducing oncotic pressure), muscle wasting, poor growth, apathy/lethargy, and increased susceptibility to infection due to impaired immune function from inadequate antibody and immune cell production. Final answer: protein supports growth/repair, enzyme/hormone synthesis, immune function (antibodies) and secondary energy provision; severe childhood deficiency causes kwashiorkor, with oedema, muscle wasting, poor growth and increased infection risk.

[1] function: growth and repair of body tissue; [1] function: synthesis of enzymes and/or hormones; [1] function: component of antibodies/immune function, or secondary energy source; [1] correctly names kwashiorkor and describes oedema as a symptom; [1] a further correct symptom of kwashiorkor (e.g. muscle wasting, poor growth, apathy, or increased susceptibility to infection). Maximum 5 marks.

Level of response guidance (indicative content, to be marked using the 4-band rubric below): Pregnancy - folate requirements increase, particularly important before conception and in the first trimester, to support neural tube development in the early embryo and reduce the risk of neural tube defects such as spina bifida; iron requirements increase to support the substantial expansion of maternal blood volume and to supply the growing foetus and placenta, helping to reduce the risk of maternal anaemia; vitamin A must be managed carefully, since while it is needed in normal amounts for foetal development, excess intake (e.g. from liver or high-dose supplements) is teratogenic and can cause birth defects, so pregnant women are advised to avoid liver and high-dose supplements; vitamin D and calcium needs remain important to support mineralisation of the developing foetal skeleton; energy requirements increase, but this increase is concentrated mainly in the third trimester, reflecting the period of most rapid foetal growth, rather than being spread evenly across pregnancy. Lactation - energy requirements increase further during lactation, to provide the energy content of the milk produced, generally requiring a greater additional energy allowance than pregnancy; protein requirements increase to provide the amino acids needed to synthesise milk proteins; calcium and vitamin D needs remain elevated, since calcium is secreted into breast milk and, if dietary calcium is insufficient, will be drawn from maternal bone stores, so adequate intake helps protect the mother's own bone health; adequate fluid intake is also important to support breast milk volume. Physiological basis - throughout, these increased needs reflect the additional biological demands of supporting rapid foetal cell division and tissue growth, placental development, expanded maternal blood volume and tissue, and (during lactation) the synthesis and secretion of nutritionally complete breast milk. Final answer: pregnancy increases folate, iron, vitamin D/calcium and (mainly third-trimester) energy needs while requiring caution with vitamin A; lactation further increases energy, protein, calcium/vitamin D and fluid needs, all reflecting the physiological demands of foetal growth, placental development and milk production.

Levels of response mark scheme (12 marks, 4 bands). Highly Competent (10-12 marks): discusses at least four distinct, accurate nutrient/energy needs for pregnancy and at least two for lactation, each with a correct physiological explanation of why the need arises; accurate specialist vocabulary throughout; clear, coherent, well-structured writing. Competent (7-9 marks): discusses several relevant needs across both pregnancy and lactation with generally correct explanation, though may be less complete or slightly less precise; mostly accurate vocabulary; generally clear writing. Adequate (4-6 marks): identifies some relevant nutrient/energy needs for pregnancy and/or lactation with limited physiological explanation; writing is understandable but with noticeable gaps or errors. Basic (1-3 marks): identifies one or two relevant points with little or no explanation; writing may be list-like or contain errors that hinder meaning. 0 marks: no creditable response.

Level of response guidance (indicative content, to be marked using the 4-band rubric below): Vitamin A - important for vision in low light (as a component of the visual pigment rhodopsin), for the growth and differentiation of epithelial cells, and for immune function; deficiency causes night blindness, potentially progressing to xerophthalmia and permanent blindness in severe cases, alongside increased susceptibility to infection; excess (typically from supplements or foods very high in preformed vitamin A) can cause liver damage and is teratogenic, causing birth defects if taken in excess during pregnancy. Vitamin D - essential for the absorption of calcium (and phosphorus) from the gut and for the mineralisation of bone; deficiency causes rickets in children (soft, poorly mineralised, sometimes bowed bones) and osteomalacia in adults (bone pain and weakness); excess, usually only from over-supplementation since sunlight synthesis is self-limiting, can cause hypercalcaemia (abnormally high blood calcium), which can damage the kidneys and other tissues. Vitamin E - acts as an antioxidant, helping to protect cell membranes, which are rich in polyunsaturated fatty acids, from oxidative damage; deficiency is rare in humans but, where it occurs, can impair nerve and muscle function; there is no strong evidence of toxicity from food sources, though very high supplemental doses may interfere with blood clotting. Vitamin K - required for the synthesis of several blood clotting factors in the liver; deficiency impairs the blood's ability to clot properly, increasing the risk of excessive bleeding (this is why newborn infants, who have low vitamin K stores, are often given a vitamin K supplement at birth); toxicity from natural vitamin K in food is rare. Overall evaluation - because vitamins A, D, E and K are fat-soluble, they can be stored in the body's fat tissue and liver rather than being readily excreted in urine as water-soluble vitamins are; this means that, while it is difficult to consume toxic amounts from food alone, excess intake from concentrated sources such as high-dose supplements poses a greater realistic risk of toxicity for these vitamins than for most water-soluble vitamins, making appropriate (not excessive) intake, rather than simply 'more is better', nutritionally important for this group. Final answer: each fat-soluble vitamin has a distinct essential function (vision/immunity for A, calcium absorption/bone health for D, antioxidant protection for E, blood clotting for K), with characteristic deficiency diseases, and because they can be stored in the body, excess intake (mainly from supplements) carries a genuine toxicity risk unlike most water-soluble vitamins.

Levels of response mark scheme (12 marks, 4 bands). Highly Competent (10-12 marks): accurately discusses the function, a deficiency consequence and an excess consequence for all four vitamins (A, D, E, K), with a clear evaluative conclusion about the storage/toxicity implications of being fat-soluble; accurate specialist vocabulary throughout; clear, coherent, well-structured writing. Competent (7-9 marks): discusses function and at least one consequence (deficiency or excess) for at least three of the four vitamins, with generally correct explanation; mostly accurate vocabulary; generally clear writing. Adequate (4-6 marks): discusses function and/or deficiency/excess for two or three vitamins with limited depth or an inaccuracy; writing is understandable but with noticeable gaps or errors. Basic (1-3 marks): identifies one or two relevant points about one or two vitamins with little explanation; writing may be list-like or contain errors that hinder meaning. 0 marks: no creditable response.

The energy content of food is commonly expressed in kilocalories (kcal), often referred to informally as 'calories', and in kilojoules (kJ), the SI (scientific) unit of energy, with food labels in the UK typically showing both. Final answer: kilocalories (kcal) and kilojoules (kJ).

[1] for both kilocalories (kcal) and kilojoules (kJ) named; accept 'calories' as equivalent to kilocalories.

Obesity is associated with an increased risk of a number of health problems, including type 2 diabetes (due to increased insulin resistance), cardiovascular disease (via effects on blood cholesterol, blood pressure and inflammation), and certain cancers (such as bowel and breast cancer). Other accepted health problems include hypertension, osteoarthritis (from increased joint loading), and sleep apnoea. Final answer: type 2 diabetes, cardiovascular disease and certain cancers.

[1] mark for each valid health problem named, to a maximum of 3. Accept: type 2 diabetes, cardiovascular disease, certain cancers, hypertension, osteoarthritis, sleep apnoea.

When alcohol is consumed, the liver prioritises its metabolism over other metabolic processes, including the oxidation (breakdown for energy) of fat. This means that with excessive or regular alcohol intake, fat is instead increasingly stored within liver cells, which can lead to a build-up known as fatty liver (hepatic steatosis) over time. Alcohol metabolism in the liver can also interfere with the liver's normal production of glucose from other sources (gluconeogenesis), which is particularly important between meals or overnight; this means excessive alcohol consumption, especially without adequate food intake, can increase the risk of hypoglycaemia (abnormally low blood glucose). Alcohol also contributes additional 'empty' calories to the diet, providing energy but few other nutrients, which can contribute to weight gain over time. Final answer: excessive alcohol reduces fat oxidation and promotes fat storage in the liver, and can disrupt glucose production, increasing hypoglycaemia risk, particularly with low food intake.

[1] the liver prioritises alcohol metabolism over fat metabolism; [1] correctly links this to reduced fat oxidation/fat accumulation in the liver (fatty liver); [1] alcohol can disrupt gluconeogenesis/glucose production in the liver; [1] correctly links this to an increased risk of hypoglycaemia, particularly with low food intake.

Insulin resistance occurs when the body's cells, particularly muscle, fat and liver cells, become less responsive to the action of insulin, the hormone that normally signals these cells to take up glucose from the blood. Excess body fat, especially fat stored around the abdomen (visceral fat), is strongly associated with increased insulin resistance, partly through the release of fatty acids and inflammatory signalling molecules that interfere with insulin's action on cells. As cells become less responsive to insulin, less glucose is taken up from the blood, so blood glucose levels remain elevated after eating. Initially, the pancreas compensates by producing more insulin (hyperinsulinaemia) to try to maintain normal blood glucose levels. However, over time, this increased demand can lead to the insulin-producing beta cells in the pancreas becoming less effective or exhausted, so insulin production can no longer fully compensate, resulting in the persistently raised blood glucose levels that characterise type 2 diabetes. Final answer: excess (particularly abdominal) body fat increases insulin resistance, reducing glucose uptake by cells; the pancreas compensates with more insulin until this response becomes insufficient, causing persistently high blood glucose.

[1] correctly identifies insulin resistance as reduced cell sensitivity/response to insulin; [1] correctly links excess (particularly abdominal/visceral) body fat to increased insulin resistance; [1] correctly explains the consequence of reduced glucose uptake by cells/raised blood glucose; [1] correctly explains the pancreas's compensatory response (increased insulin production) and its eventual insufficiency.

A number of barriers can prevent consumers from making healthy food choices, even when they are aware of dietary advice. Resources are a significant barrier: healthier foods, such as fresh fruit, vegetables and lean protein, can be more expensive and more time-consuming to prepare than energy-dense processed alternatives, which particularly affects consumers with a limited income or limited time (for example, due to long working hours). Availability is also a barrier in some areas, where there is limited local access to a wide range of affordable fresh food, sometimes referred to as a 'food desert'. Food labelling can act as a barrier when it is complex, inconsistent, or difficult for consumers to interpret quickly while shopping, making it harder to identify the healthier option even when a consumer wants to. Food advertising is a further barrier, since food and drink marketing, including via television and social media, disproportionately promotes energy-dense, low-nutrient foods, shaping preferences and normalising less healthy choices, particularly among children and young people. Evaluating these barriers together, they show that healthy eating is not simply a matter of individual knowledge or willpower; even a well-informed consumer can be constrained by cost, time, local availability, unclear labelling and a food environment that is heavily marketed towards less healthy options, meaning that public health strategies need to address these wider structural barriers as well as individual education. Final answer: resources, availability, food labelling and food advertising each act as genuine barriers that can prevent even informed consumers from consistently making healthy food choices.

[1] resources, correctly explained (e.g. cost/time); [1] availability, correctly explained (e.g. limited local access to fresh food); [1] food labelling, correctly explained (e.g. complexity/difficulty interpreting); [1] food advertising, correctly explained (e.g. marketing of less healthy foods); [1] for a valid evaluative conclusion recognising that these barriers can affect choice independently of a consumer's knowledge/intentions. Maximum 5 marks.

Regular physical activity provides a wide range of health benefits for adults. It improves cardiovascular function by strengthening the heart muscle and improving circulation, which can help reduce resting blood pressure and reduce the risk of cardiovascular disease over time. Weight-bearing physical activity supports bone and joint health, helping to maintain or increase bone density (reducing the long-term risk of osteoporosis) and supporting the mobility and function of joints. Physical activity also supports skeletal muscular health, helping to maintain muscle mass and strength, which is particularly important for functional independence as adults age. In terms of energy balance, physical activity increases energy expenditure, which, combined with an appropriate dietary energy intake, supports the achievement and maintenance of a healthy body weight. Finally, physical activity has recognised mental health benefits, including reducing stress, anxiety and the risk of depression, and improving mood and sleep quality. Final answer: regular physical activity benefits cardiovascular function, bone and joint health, skeletal muscular health, energy balance/weight management, and mental health.

[1] cardiovascular function benefit, correctly explained; [1] bone and joint health benefit, correctly explained; [1] skeletal muscular health benefit, correctly explained; [1] energy balance/weight management benefit, correctly explained; [1] mental health benefit, correctly explained; [1] for a well-organised discussion covering at least five distinct, correctly explained benefits. Maximum 6 marks.

A number of dietary factors are thought to influence cancer risk. A high intake of processed and red meat has been linked to an increased risk of certain cancers, particularly colorectal (bowel) cancer, and a high salt intake has been linked to an increased risk of stomach cancer, potentially through damage to the stomach lining. In contrast, a high intake of wholegrain plant foods and of fruit and vegetables has been linked to a reduced cancer risk; wholegrain foods provide fibre, which may dilute carcinogens in the gut, speed up transit time (reducing the time harmful substances are in contact with the gut lining), and produce protective compounds during fermentation in the large intestine, while fruit and vegetables provide antioxidant nutrients, such as vitamin C and beta-carotene, which may help protect cells from oxidative damage linked to the development of cancer. A high overall fat intake can also increase cancer risk, partly through its contribution to excess body fat/obesity, which is itself an independent risk factor for several cancers. Final answer: high processed/red meat and high salt intake increase cancer risk, while wholegrain foods, fruit/vegetables and antioxidant nutrients are linked to reduced risk, and high fat intake can increase risk partly via obesity.

[1] processed/red meat linked to increased risk (e.g. colorectal cancer); [1] high salt intake linked to increased risk (e.g. stomach cancer); [1] wholegrain plant foods and/or fibre linked to reduced risk, with a valid mechanism; [1] fruit/vegetables and/or antioxidant nutrients linked to reduced risk, with a valid mechanism; [1] high fat intake linked to increased risk, e.g. via obesity. Maximum 5 marks.

Several modifiable lifestyle factors increase the risk of cardiovascular disease (CVD). Smoking damages the lining of the arteries and promotes inflammation, accelerating the build-up of atheroma (fatty deposits) and the narrowing of arteries (atherosclerosis). Reduced physical activity contributes to poorer cardiovascular fitness, less effective blood cholesterol control, and a higher likelihood of becoming overweight, all of which raise CVD risk. A low fruit and vegetable intake reduces intake of antioxidant nutrients, fibre and potassium, which have protective effects on the cardiovascular system, including helping to regulate blood pressure. Excessive alcohol intake can raise blood pressure and contribute to weight gain, both of which increase CVD risk. High blood cholesterol, often resulting from a diet high in saturated fat, contributes to the formation of atheroma in artery walls. A high sodium (salt) intake raises blood pressure (hypertension), which places additional strain on the heart and blood vessels. Finally, a low intake of soluble fibre removes a dietary factor that would otherwise help to lower blood cholesterol levels, since soluble fibre binds to cholesterol/bile acids in the gut and reduces their reabsorption. Final answer: smoking, reduced physical activity, low fruit/vegetable intake, excessive alcohol, high blood cholesterol, high sodium intake and low soluble fibre intake are all modifiable lifestyle factors that increase CVD risk.

[1] mark per correctly explained modifiable risk factor, to a maximum of 5, selected from: smoking; reduced physical activity; low fruit and vegetable intake; excessive alcohol intake; high blood cholesterol; low antioxidant status; high sodium intake; low soluble fibre intake. Each point requires both correct identification of the factor and a valid link to increased CVD risk to be credited.

Level of response guidance (indicative content, to be marked using the 4-band rubric below): Energy balance - energy balance describes the relationship between energy intake, from the food and drink a person consumes, and energy expenditure, made up of basal metabolic rate (BMR, the energy used for essential body functions at rest), the thermic effect of food (energy used in digestion), and energy used in physical activity. When intake and expenditure are equal, body weight remains stable; when intake regularly exceeds expenditure (a positive energy balance/energy surplus), the excess energy is stored as body fat, leading to weight gain over time, which is the underlying mechanism behind overweight and obesity; conversely, a negative energy balance (expenditure exceeding intake) leads to weight loss. Dietary recommendations - reducing portion sizes and the proportion of energy-dense, nutrient-poor foods (such as those high in added sugar and saturated fat) in the diet reduces energy intake without necessarily requiring extreme dietary restriction, helping to create a sustainable energy deficit; this is justified because it reduces energy intake while still allowing a varied, adequately nutritious diet, unlike very restrictive diets which are harder to sustain and can risk nutrient deficiency. Physical activity recommendations - increasing both structured exercise and everyday incidental activity (e.g. walking, reducing sedentary time) increases energy expenditure, contributing to the energy deficit needed for weight loss; this is justified because physical activity also brings additional health benefits (e.g. cardiovascular, mental health) beyond weight management, and helps preserve lean muscle mass during weight loss, supporting a higher metabolic rate. Rate and approach - a gradual, sustainable rate of weight loss, such as around 0.5 to 1 kg per week, is generally recommended rather than very rapid weight loss; this is justified because gradual weight loss is more likely to be maintained long-term, is less likely to trigger excessive hunger or nutrient inadequacy, and avoids the loss of lean tissue that can accompany very rapid weight loss. Behaviour-change strategies, such as keeping a food diary to increase awareness of intake, setting realistic goals, and gradually building new habits (e.g. reducing screen time/sedentary behaviour), are also recommended and justified on the basis that sustainable weight management depends on long-term behaviour change rather than short-term restriction alone. Final answer: overweight results from a sustained positive energy balance; effective, justified recommendations combine a modest reduction in energy-dense food/portion size, increased physical activity, a gradual sustainable rate of weight loss, and behaviour-change support, together creating a manageable, maintainable energy deficit.

Levels of response mark scheme (15 marks, 4 bands). Highly Competent (12-15 marks): explains energy balance accurately with reference to both intake and the components of expenditure (BMR, activity, thermic effect of food), correctly links a sustained energy surplus to weight gain, and proposes at least three distinct, well-justified recommendations (dietary, physical activity, and behavioural/rate-related) with clear reasoning for each; accurate specialist vocabulary throughout; clear, coherent, well-structured writing. Competent (8-11 marks): explains energy balance with reasonable accuracy and proposes at least two justified recommendations with generally sound reasoning; mostly accurate vocabulary; generally clear writing with minor errors. Adequate (4-7 marks): shows a basic understanding of energy balance and identifies one or two relevant recommendations with limited justification; writing is understandable but with noticeable gaps or errors. Basic (1-3 marks): very limited or largely inaccurate explanation of energy balance, with little or no justified recommendation; writing may be list-like or contain errors that hinder meaning. 0 marks: no creditable response.

Level of response guidance (indicative content, to be marked using the 4-band rubric below): Risk-increasing dietary factors - a high intake of processed and red meat is linked to increased cancer risk (particularly colorectal cancer), thought to be partly due to compounds such as N-nitroso compounds formed during processing or high-temperature cooking, which can damage the DNA of cells lining the gut; a high salt intake is linked to increased stomach cancer risk, potentially through damaging the protective lining of the stomach, making it more vulnerable to damage from other factors. Protective dietary factors - wholegrain plant foods provide fibre, which may dilute the concentration of carcinogens in the gut, speed up the transit time of gut contents (reducing the length of time harmful substances are in contact with the gut lining), and be fermented by gut bacteria into compounds that may have protective effects on gut cells; fruit and vegetables provide antioxidant nutrients (such as vitamin C and carotenoids) which can help protect cell DNA from oxidative damage caused by free radicals, a process implicated in the development of cancer. Lifestyle factors increasing risk - excess body fat produces hormones (such as oestrogen) and inflammatory signalling molecules that can promote cell proliferation, a mechanism linked to increased risk of several cancers; alcohol is metabolised in the body to acetaldehyde, a recognised carcinogen that can directly damage DNA; smoking exposes tissues directly to a large number of carcinogenic chemicals that cause DNA damage in exposed cells, particularly in the lungs and airways; excessive sun exposure exposes skin cells to UV radiation, which can damage skin cell DNA and is strongly linked to skin cancer risk. Protective lifestyle factors - regular physical activity is associated with a reduced cancer risk, partly through helping to control body fat levels and through beneficial effects on hormone regulation and immune function; breastfeeding is associated with a reduced risk of breast cancer in the mother, thought to relate to hormonal changes associated with lactation. Recommendations - dietary and lifestyle recommendations to reduce cancer risk can be proposed and justified from this evidence, including reducing processed/red meat and salt intake, increasing wholegrain foods, fruit and vegetables, maintaining a healthy body weight through diet and physical activity, limiting alcohol intake, not smoking, and protecting skin from excessive sun exposure, each justified by the specific mechanism it addresses. Final answer: processed/red meat and high salt intake increase cancer risk through DNA-damaging compounds and stomach lining damage respectively, while wholegrain foods, fruit/vegetables and antioxidants are protective; among lifestyle factors, excess body fat, alcohol, smoking and sun exposure increase risk through hormonal, carcinogenic or DNA-damaging mechanisms, while physical activity and breastfeeding are protective.

Levels of response mark scheme (15 marks, 4 bands). Highly Competent (12-15 marks): discusses at least three dietary factors and at least three lifestyle factors, explaining a specific, accurate mechanism for each, and proposes justified recommendations linked to the mechanisms discussed; accurate specialist vocabulary throughout; clear, coherent, well-structured writing. Competent (8-11 marks): discusses several dietary and lifestyle factors with generally correct mechanisms, though may be less complete or less precise for some; mostly accurate vocabulary; generally clear writing with minor errors. Adequate (4-7 marks): identifies some relevant dietary and/or lifestyle factors with limited or partially correct explanation of mechanism; writing is understandable but with noticeable gaps or errors. Basic (1-3 marks): identifies one or two relevant factors with little or no explanation of mechanism; writing may be list-like or contain errors that hinder meaning. 0 marks: no creditable response.

Level of response guidance (indicative content, to be marked using the 4-band rubric below): Non-modifiable risk factors - cardiovascular disease (CVD) risk is influenced by non-modifiable factors including genetics (family history), gender (men are generally at higher risk at a younger age than pre-menopausal women), age (risk increases with age), socio-economic status, ethnicity, and low birth weight; these establish a baseline level of risk that cannot be changed through diet or lifestyle. Modifiable dietary/lifestyle risk factors and mechanisms - smoking damages the lining of the arteries (the endothelium) and promotes inflammation, accelerating the build-up of atheroma and narrowing of the arteries (atherosclerosis); reduced physical activity and a low fruit and vegetable intake (providing less antioxidant, fibre and potassium intake) both reduce the body's protective capacity against these processes; excessive alcohol intake can raise blood pressure and contribute to weight gain; a diet high in saturated fat raises LDL ('bad') cholesterol, which is deposited in artery walls as atheroma, narrowing the arteries and restricting blood flow; a high sodium intake raises blood pressure (hypertension), placing additional strain on the cardiovascular system; a low soluble fibre intake removes a dietary factor that would otherwise help lower blood cholesterol. Related conditions - overweight and obesity, hypertension, and type 2 diabetes are all themselves influenced by diet and lifestyle and, in turn, each independently increases CVD risk, meaning their effects can compound; elevated homocysteine (an amino acid byproduct influenced partly by B vitamin status, particularly folate, B12 and B6) is also implicated in damaging blood vessel walls and increasing CVD risk. Prevention - dietary and lifestyle recommendations to reduce CVD risk, justified by these mechanisms, include reducing saturated fat and sodium intake, increasing fruit, vegetables and soluble fibre intake, maintaining a healthy body weight, increasing physical activity, moderating alcohol intake, and not smoking. Evaluation - overall, diet and lifestyle play a substantial and largely modifiable role in CVD risk, and addressing the modifiable factors can meaningfully reduce an individual's overall risk; however, because non-modifiable factors such as genetics, age and gender also contribute to baseline risk, diet and lifestyle changes can reduce but cannot completely eliminate an individual's risk of developing CVD. Final answer: modifiable dietary/lifestyle factors act through mechanisms such as raised LDL cholesterol, hypertension and elevated homocysteine to significantly influence CVD risk and can be addressed through targeted recommendations, but non-modifiable factors mean diet and lifestyle changes reduce, rather than eliminate, overall risk.

Levels of response mark scheme (15 marks, 4 bands). Highly Competent (12-15 marks): distinguishes non-modifiable from modifiable risk factors, explains at least three modifiable dietary/lifestyle mechanisms accurately (e.g. LDL cholesterol/atheroma, hypertension, homocysteine), discusses at least one related condition (obesity, hypertension or type 2 diabetes), proposes justified prevention recommendations, and reaches a balanced evaluative conclusion about modifiable versus non-modifiable risk; accurate specialist vocabulary throughout; clear, coherent, well-structured writing. Competent (8-11 marks): identifies non-modifiable and modifiable factors and explains at least two mechanisms with reasonable accuracy, with some prevention recommendations; mostly accurate vocabulary; generally clear writing with minor errors. Adequate (4-7 marks): identifies some relevant risk factors with limited explanation of mechanism or evaluation; writing is understandable but with noticeable gaps or errors. Basic (1-3 marks): identifies one or two relevant risk factors with little or no explanation; writing may be list-like or contain errors that hinder meaning. 0 marks: no creditable response.