Edexcel International AS Biology Diet & Health PDF

Head to www.savemyexams.com for more awesome resources Edexcel International AS Biology Your notes Diet & Health Contents 1.12 Reducing Risk Factors of CVD 1.13 Dietary Antioxidants & CVD 1.14 Core Practical 2: Investiga...

Head to www.savemyexams.com for more awesome resources Edexcel International AS Biology Your notes Diet & Health Contents 1.12 Reducing Risk Factors of CVD 1.13 Dietary Antioxidants & CVD 1.14 Core Practical 2: Investigate the Vitamin C Content of Food & Drink 1.15 Interpreting Data on Risk Factors 1.16 Designing Studies into the Effects of Risk Factors 1.17 Perception of Risk vs Actual Risk 1.18 Data on Cholesterol & Lipoproteins 1.19 Data on Effect of Diet 1.20 Treatments for CVD - Benefits & Risks Page 1 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources 1.12 Reducing Risk Factors of CVD Your notes CVD Risk Factors There are many lifestyle factors that can increase the risk of cardiovascular disease (CVD) CVD is a general term for conditions affecting the heart and blood vessels It is usually associated with Atherosclerosis; the formation of hard plaques in the artery lining Thrombosis; the formation of blood clots in the arteries Risk factors are factors that can be linked to an increased risk of a disease Exposure to a risk factor doesn’t guarantee that an individual will suffer a disease, e.g. a person who smokes regularly isn’t guaranteed to develop lung cancer but their risk compared to someone who doesn’t smoke is much higher Certain risk factors are correlated with certain diseases, but correlations are not always causations Risk factors can be Aspects of a person’s lifestyle such as the food they eat or whether or not they drink alcohol Substances in a person’s body or environment such as air pollution in a crowded city or asbestos in old buildings Genetic predispositions to developing certain diseases Other biological factors such as age or biological sex Many diseases are caused by the interaction of a number of factors E.g. the chance of developing CVD is higher in individuals who have a diet high in cholesterol, don’t exercise regularly, and smoke; all of these behaviours increase the likelihood of damage occurring to the arteries Some factors, such as those related to lifestyle, are to some extent under the control of the individual It is usually possible to make decisions about diet, smoking, alcohol intake, and exercise levels Note that scientists are becoming increasingly aware that the best choices are easier to make for some than others; unhealthy food choices are often cheaper and easier, and not everyone has time to exercise Other factors are outside of an individual's control, such as genetics, biological sex, and age Lifestyle Factors Linked to CVD Table Page 2 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Other Factors Linked to CVD Table Page 3 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Page 4 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources 1.13 Dietary Antioxidants & CVD Your notes Dietary Antioxidants & CVD We know that eating fruits and vegetables is good for us; one reason that has been proposed to explain this is that these foods are high in chemicals called antioxidants Antioxidants include vitamins such as Vitamin A; found in orange vegetables such as carrots and sweet potato Vitamin C; found in citrus fruits Vitamin E; found in leafy vegetables, some nuts, and some oils Some research into antioxidants has been held up in support of the theory that antioxidants in the diet reduce the risk of heart disease, but more recent data analysis has suggested that there is not enough evidence to conclude this Some recent research even suggests that antioxidants could increase the risk of heart disease The evidence for antioxidants We know that vitamin C is important for the formation of connective tissues in the body, so it is logical to think that an increase in dietary vitamin C could help to reduce the damage to the artery endothelial layer that leads to atherosclerosis Atherosclerosis is the process by which fatty plaques called atheromas develop inside a damaged arterial lining In a study involving 1 605 men in Finland, 70 men had a heart attack between 1984 and 1992 13.2 % of the men with low vitamin C levels had a heart attack 3.8 % of the men with normal vitamin C levels had a heart attack Many concluded from this study that increasing vitamin C intake would reduce the risk of heart disease Inconclusive evidence A large analysis of many studies on vitamin C and heart disease was carried out in 2016 A study that analyses the results of many existing studies is known as a meta-analysis The 2016 study showed that there was no clear relationship between increased vitamin C intake and a reduced risk of heart disease The study also suggested that taking antioxidant supplements could be harmful to circulatory system health This is an example of an area of study with conflicting evidence; it is essential that all evidence is taken into account when drawing conclusions or deciding that evidence is still inconclusive Page 5 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources 1.14 Core Practical 2: Investigate the Vitamin C Content of Food & Drink Your notes Investigating the Vitamin C Content of Food & Drink Vitamin C is found in green vegetables, fruits, and potatoes It is essential for a healthy diet The chemical name for vitamin C is ascorbic acid Ascorbic acid is a good reducing agent and therefore it is easily oxidised Methods for the detection of vitamin C involve titrating it against a solution of an oxidising agent called DCPIP DCPIP is a blue dye that turns colourless in the presence of vitamin C Titration is a method of chemical analysis that involves determining the quantity of a substance present by gradually adding another substance; in this case the concentration of vitamin C is determined by gradual addition of a vitamin C solution to DCPIP Apparatus Vitamin C solutions 1% DCPIP solution Distilled water Range of fruit juices Measuring cylinder Pipette Stop watch Test tubes Method 1. Make up a series. e.g. six, of known vitamin C concentrations This can be done by serial dilution 2. Use a measuring cylinder to measure out 1 cm3 of DCPIP solution into a test tube 3. Add one of the vitamin C solutions, drop by drop, to the DCPIP solution using a graduated pipette or burette 4. Shake the tube for a set period of time using a stop watch It is important to keep the shaking time the same for each concentration; this is a control variable 5. When the solution turns colourless record the volume, in number of drops, of vitamin C solution added 6. Repeat steps 2-5 for the same concentration twice more and calculate an average 7. Repeat steps 2-6 for each of the known concentrations 8. Results can be plotted as a line of best fit showing the average volume of vitamin C needed to decolourise DCPIP against the concentration of vitamin C This is a calibration curve and can be used to find the concentration of vitamin C in unknown samples such as fruit juices Page 6 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Drops of vitamin C solution of known concentration can be added to DCPIP to determine the volume required for the DCPIP to be decolourised Risk assessment DCPIP is an irritant Avoid contact with the skin Wear eye protection Results The volume of vitamin C solution required to decolourise DCPIP should decrease as the concentration of the vitamin C solution increases The results of the experiment can be plotted on a graph of volume of vitamin C needed to decolourise DCPIP against the concentration of vitamin C The line of best fit for such a graph is known as a calibration curve; unknown substances can be compared to it to gain an estimate of their vitamin C concentration Page 7 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources The calibration curve produced from this experiment can be used to estimate the concentration of vitamin C in fruit juices Your notes A graph of volume of vitamin C needed to decolourise DCPIP against vitamin C concentration can be used as a calibration curve to estimate the vitamin C concentration of unknown substances Page 8 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources 1.15 Interpreting Data on Risk Factors Your notes Quantitative Data on Illness Analysing data on illness and mortality Analysing data on illness and mortality is an essential part of the study of risk factors It is important to remember that correlation between a risk factor and a diseases does not always mean that a causal relationship exists Scientists cannot assume that because there is correlation between variables that one has caused the other Many other factors will influence the prevalence and likelihood of disease and these factors need to be taken into account when analysing and interpreting data Describing data This means identifying trends and stating what the results show e.g. the data show that the oldest age group has the highest relative risk of heart disease When describing data, it is always good to use numbers from the data to back up your descriptions, e.g. the data show that the oldest age group of 80+ has the highest relative risk of heart disease of 2.4 Drawing conclusions from data This means working out what the data show about the relationships between variables, e.g. the data show that there is an association, or correlation, between age and the relative risk of heart disease Conclusions should always be limited to what the data show Causal relationships cannot be concluded from one data set, e.g. it cannot be concluded from one study that older age causes an increase in the relative risk of heart disease Conclusions cannot be extrapolated beyond the setting of a study e.g. a study carried out in 40-50 year old adults cannot be applied to people over 70, and a study carried out in mice cannot be directly applied to humans Evaluating the validity of data Larger sample sizes are more likely to give valid results as the sample is more likely to be representative of the population in question Results are considered to be valid if they measure what they set out to measure, i.e. they are not influenced by external variables or poor experimental design, and have been analysed correctly Statistical analysis should be used to check that any differences between results are statistically significant Some studies need to have a control with which to compare the results E.g. when testing a drug to treat heart disease, a control group that is not given the drug should be included in the study to ensure that any effect shown is due to the drug and not any other factor Studies should be repeated, or there should be many studies that show the same result, before conclusions can be drawn Page 9 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources The study should be designed to control any variable that is not being tested Researchers should not be biased, i.e. looking for a particular outcome This could be a problem if someone is being paid to come up with a particular result Your notes Worked example A study was carried out into the relative risk of CVD in non-smoking adults exposed to a range of levels of cigarette smoke from a smoking partner. The study looked at 523 non-smoking partners of smokers. a. Describe the data b. Draw a conclusion from the data c. Comment on the validity of the data a. A description for this data could include the following Non-smokers exposed to 0 cigarettes per day have the lowest relative risk of CVD, with a relative risk of 1.00 Non-smokers exposed to 20 or more cigarettes per day have the highest risk of CVD, with a relative risk of 1.31 As the number of cigarettes smoked per day increases, the relative risk of CVD increases from 1.00 at 0 cigarettes per day, to 1.23 at 1-19 cigarettes per day, and then to 1.31 at 20 or more cigarettes per day b. A conclusion for the data could be There is a correlation, or an association, between increased exposure to cigarette smoke and an increased risk of CVD Page 10 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Note that while it could be concluded here that increased exposure to smoking causes an increase in the relative risk of CVD, it is best not to draw causal connections without more evidence This is only a single study; there may be concerns over its validity, and other studies could show Your notes conflicting evidence c. A commentary on the validity of the data could include The study included 523 people; this is a fairly small sample size and may not represent an entire population This is only one study; more studies would need to be carried out to back up these results Being able to replicate, or repeat, the results of a study shows that the results are reliable There is no information on how other risk factors might be interacting with smoking to influence the risk of CVD Risk factors such as age, diet, biological sex, or exercise levels may be playing a role, as these factors may be interacting with the smoking variable e.g. Smokers are often older More men may smoke than women Smokers may be less likely to exercise The data doesn't comment on the use of any statistical tests so we cannot state the significance of the differences between the different levels of smoke exposure Recognising conflicting evidence Evidence from one study is not enough to conclude that a risk factor is a risk to health or associated with a particular disease Studies similar in design would need to be analysed together to make links Such an analysis is referred to as a meta-analysis Similar conclusions would need to be drawn from all studies in order to accept the findings Conflicting evidence may be found that leads to a different conclusion Conflicting evidence is that which shows a different pattern to the evidence gained elsewhere When conflicting evidence arises, more research is needed to show which pattern is correct Conflicting evidence is often a sign that other variables are involved Examiner Tip Beware of mixing up correlation and causation. Correlation is where a change in one variable occurs at the same time as a change in another variable. Causation is where the change in one variable causes the change in another variable. Just because two factors correlate does not mean one causes the other. Be mindful with the words you use when answering questions on data. Page 11 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources 1.16 Designing Studies into the Effects of Risk Factors Your notes Features of a Good Study on Illness There are a number of factors to consider when evaluating the design of a study The sample of people included in the study Sample size should be representative of the population involved; larger samples are more likely to be representative Randomly selecting participants removes bias and increases the likelihood of a representative sample Selecting people from among friends or from among people at a gym, for example, is likely to select people who have similar lifestyles; this would be a biased sample Control variables; the more variables that have been controlled, the more reliable and valid the data Reliable data can be reproduced by repeating an experiment Valid data has only tested one independent variable whilst all other variables are controlled Avoiding bias; there should be no bias involved in the collection or analysis of data Bias in data can come from human sources, e.g. by selecting a non-random sample or manipulating data to emphasise a certain outcome Bias can be a problem when, e.g. scientists are employed by a company that desires a particular result, or when scientific funding is dependent on specific outcomes Controls; the use of an experimental control provides a point of comparison and ensures that the results are due to the variable of interest An experimental control condition in a study should be the same as every other condition except that the independent variable should be absent, e.g. in a drug trial the control group would be identical to the group receiving the trial drug, except that they would be given a sugar pill instead of the drug; this is known as a placebo Repetition; repeats of the data need to be taken within a study, and similar results should be collected Similar results are reliable Reproducible; it should be possible to reproduce a set of findings by repeating an entire investigation This is why scientists always write up the method used in a study Page 12 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources 1.17 Perception of Risk vs Actual Risk Your notes Perceived vs Actual Risk Risk is defined as the chance or probability that a harmful event will occur The statistical chance of a harmful event occurring needs to be supported by scientific evidence gained from research An individual's perception of risk may be different to the actual risk of something occurring Risk can be overestimated because of factors such as Misleading information in the media Overexposure to information Personal experience of the associated risk Unfamiliarity with the event The event causing severe harm Lack of enjoyment of an activity Risk can be underestimated because of factors such as Lack of information Misunderstanding of factors that increase the risk A lack of personal experience of the associated risk Unfamiliarity with the event The harm being non-immediate Enjoyment of an activity The statistical chance of an event occurring often bears little resemblance to someone's perception of the risk E.g. the global annual risk of being killed in a road accident is 1 in 1 547, and the global annual risk of death due to crashing during a flight is 1 in 4.5-5.5 million; despite this people are far more likely to have a fear of flying than a fear of driving Page 13 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources 1.18 Data on Cholesterol & Lipoproteins Your notes Data Analysis for Diet & Health A risk factor is any factor that increases the chance of developing a particular condition or disease An increase in a risk factor does not guarantee the development of disease, but increases the risk An example of a risk factor for the incidence of CVD is increased blood cholesterol An increase in the presence of a risk factor would be expected to lead to increased incidence of disease The incidence of disease describes the number of cases of a disease that occur within a particular group of people within a given time Cholesterol Cholesterol is a type of lipid produced in the body Cells require a source of cholesterol for cell membrane functioning, sex hormone structure, and the synthesis of bile Cholesterol is transported around the body as lipoproteins Lipoproteins are molecules composed of lipid and protein There are two types of lipoproteins; high density lipoproteins (HDLs) and low density lipoproteins (LDLs) The balance of HDLs and LDLs in the blood is thought to be an important factor in the risk of developing heart disease High density lipoproteins HDLs contain unsaturated fat, cholesterol, and protein These molecules transport cholesterol from body tissues to the liver to be recycled or excreted; they are responsible for reducing blood cholesterol levels when it is too high HDLs are also thought to contribute to the removal of cholesterol from the fatty plaques that form during atherosclerosis Low density lipoproteins LDLs contain saturated fat, cholesterol, and protein The role of LDL is to move cholesterol from the liver into the bloodstream where it remains until it is required by the cells; they increase blood cholesterol levels when it is too low LDLs bind to receptors on cell surface membranes, enabling them to be taken up by the cells that need them and removing cholesterol from the blood High levels of LDLs can lead to blockage of these membrane receptors, causing blood cholesterol to rise Lipoproteins and heart disease LDLs are often thought of as 'bad cholesterol' Page 14 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources When your body has too much LDL cholesterol the membrane receptors on the surface of cells are blocked, leading to an overall rise in blood cholesterol Cholesterol contributes to the formation of plaques in the arteries Your notes High density lipoproteins are often thought of as 'good cholesterol' This is because HDLs carry cholesterol to the liver where it is broken down and excreted, therefore lowering overall blood cholesterol levels Rather than one being bad and the other good, in reality it is the ratio of LDLs to HDLs that is important; the healthy ratio is thought to be roughly 3:1 of LDL:HDL It is thought that an LDL:HDL ratio larger than 5:1 increases the risk of heart disease While diet is a factor in determining the production of LDLs and HDLs in the body, the way in which the cells process lipids is also thought to be important It is important to be able to analyse data on the link between lipoproteins and CVD Evaluating data linked to risk factors There are several things that should be taken into consideration when analysing data from studies on health risk factors; if, for example, a study is conducted on the effects of smoking on lung health, then the following should be kept in mind Sample size; a study with a large sample size will give results that are more likely to be representative of the target population Individuals in the sample; the results of a study can only be applied to parts of the population represented in the sample, e.g. If the sample only contains women aged 20-40 then the results cannot be used to draw conclusions about the effect of smoking on males or older women Control group; a study of this nature needs to contain a control group so that the effects of the variable of interest can be isolated from the effects of other factors In this example the control group would contain individuals who do not smoke; this gives a base line against which the results from the smoker group can be compared All factors other than the variable of interest should be controlled between the control group and the test group, e.g. age, diet, activity levels Statistical significance; the differences between groups need to be sufficiently large to be sure that they are not just the result of random chance; this is known as being statistically significant To determine whether a difference between results is significantly different, statistical analysis needs to be carried out Statistical significance can often be determined by comparing standard deviations of two data sets If standard deviations overlap then the difference between data sets is not statistically significant If the standard deviations do not overlap then the difference is statistically significant The influence of other variables; variables other than the variable of interest need to be controlled so that they do not impact the results; in this study such control variables might include Genetics Secondary exposure to smoking Exercise levels Diet Page 15 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Worked example Your notes The graph below shows different lipoproteins with their associated cardiovascular disease rate. Note that the bars represent the standard deviations of the data sets. The study involved 300 men aged between 40 and 80. Their LDL and HDL levels were measured over a period of 30 weeks and mapped against developing CVD events such as atheromas and thrombosis 1. Describe the data 2. Draw a conclusion 3. Comment on the validity of the data. Note that validity refers to a study that successfully measures the variable that it sets out to measure, without influence from any other factors. 1. Describe the data The graph shows that the cardiovascular event rate percentage is higher with LDLs compared to HDLs The cardiovascular event rate with LDLs is around 28 % while the event rate percentage for HDLs is around 18 % 2. Draw a conclusion There is no significant difference in percentage of CVD events with LDL and HDL as there is an overlap of the standard deviation bars Page 16 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources 3. Comment on the validity of the data A sample of 300 men is very small in relation to an entire population, so needs to be larger in order to Your notes be representative Only men between 40 and 80 were sampled, so the data is not representative of the entire population Other factors relating to CVD are not measured or commented on, e.g. smoking, diet, exercise; such factors would need to be controlled between the two groups or measured so that their effect can be eliminated from the data Examiner Tip When dealing with data there are a few important things to remember It is always a good idea to include numbers when you are describing a data set Correlation is not causation; when drawing conclusions it is always best to say 'there is a correlation' or 'there is an association' between two variables rather than stating that one has caused the other Look for clues about the validity of the experiment. Is the sample representative? Have other variables been controlled? Has statistical analysis been carried out? Correlation vs Causation Evidence linking blood cholesterol to CVD High cholesterol is listed as one of the five main risk factors for heart disease by many research studies and organisations such as the British Heart Foundation and the NHS There is evidence of a correlation between high blood cholesterol levels and an increased risk of CVD Medical treatments such as statins, which reduce blood cholesterol levels also reduce risk of heart disease Diets high in saturated fats, which tends to raise LDL cholesterol levels in the blood, have been linked to increased CVD events A significant reduction in total blood cholesterol levels is linked to a decrease in major coronary events Arterial plaque regression has been observed alongside blood lipid-lowering therapy, which has led to a reduction in major cardiovascular events Note that when considering scientific evidence it is essential to remember that correlation is not the same as causation; a connection between two events, e.g. a diet high in saturated fat and raised LDL cholesterol, may not mean that one has caused the other It may be that there is a third variable that has not been measured that is influencing levels of LDL cholesterol, e.g. the presence of alleles that influence the way in which cells metabolise dietary fats Page 17 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources 1.19 Data on Effect of Diet Your notes Measurements to Reduce CVD Risk Diet Some scientific studies have linked a diet high in saturated fats to an increased risk of CVD It is worth noting that there are other studies that are inconclusive on the link between dietary saturated fat and CVD risk Studies that investigate the connection between diet and CVD can be used to educate members of the public on their consumption of certain foods Food labels now exist on most food packaging making consumers aware of what they are eating Traffic light warning labels (Red = high, Orange = medium, Green = low) also exist on many food labels to warn consumers of high levels of sugar, saturated fat, and salt People are able to make informed choices about their diets Obesity has been linked to an increase in CVD events Healthcare professionals can use a number of measures to identify obesity in patients Waste-to-hip ratio is the circumference of the waist in cm divided by the circumference of the hips in cm For women the ratio should be less than 0.86 For men the ratio should be less than 1.0 BMI is a value derived from dividing an individual's mass in kg by the square of their height (m2) A BMI of less than 18.5 indicates that the person is underweight 18.5 - 24.9 is considered normal 25 - 29.9 is considered overweight A person with a BMI of 30 or higher is considered obese Obese individuals can make lifestyle choices to reduce their weight to a healthy range Smoking Smoking has been linked to CVD by many research studies The research has led to changes in the way cigarettes are advertised Health warnings now exist on all packets TV and media portray smoking as an unhealthy lifestyle choice Free materials, including prescriptions, are available to support individuals to stop smoking Exercise Inactivity has been linked to increased risk of CVD There are many campaigns and initiatives to encourage all people to partake in more exercise Increased hours of physical education in schools Targeted encouragement at different groups of people, such as teenagers Page 18 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources 1.20 Treatments for CVD - Benefits & Risks Your notes Treatments for CVD: Benefits & Risks While reducing the risk factors and lowering the risk of developing cardiovascular disease (CVD) is the best option, CVD is still very common and treatment options are needed There are a number of different treatment options for cardiovascular disease, many of which involve taking medication Types of medication for the treatment of CVD include Antihypertensives Statins Anticoagulants Platelet inhibitors Antihypertensives These drugs work by lowering blood pressure High blood pressure is also known as hypertension Lowering blood pressure reduces the risk of arterial endothelial damage and therefore reduces the risk of atheromas and thrombosis Beta blockers, vasodilators and diuretics act as antihypertensives Beta blockers prevent increases in heart rate Vasodilators increase the diameter of the blood vessels ACE inhibitors are a type of drug that block the production of angiotensin, a hormone that causes constriction of the blood vessels This keeps the arteries dilated, which lowers the blood pressure Diuretics reduce blood volume by decreasing the amount of sodium reabsorbed into the blood by the kidneys, therefore decreasing the volume of water reabsorbed into the blood Statins These drugs work by lowering blood cholesterol They block an enzyme in the liver which is needed to make cholesterol This lowers the LDL concentration in the blood therefore reducing the risk of atheroma formation LDLs are sometimes known as 'bad' cholesterol; at high levels they increase the risk of atheromas forming Statins also reduce inflammation in the arterial lining, which lowers the risk of atherosclerosis Anticoagulants These drugs reduce blood clotting Blood clotting can be referred to as blood coagulation Warfarin is an anticoagulant that decreases the level of prothrombin in the bloodstream Reduced formation of blood clots decreases the likelihood of thrombosis and therefore reduces the risk of blood vessels being blocked by blood clots Page 19 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Platelet inhibitors These are also substances which reduce blood clotting Your notes Platelet inhibitors are a type of anticoagulant Aspirin and clopidogrel are the most commonly used examples of these drugs They prevent the clumping together of platelets, so preventing the formation of blood clots Benefits and Risks of Cardiovascular Disease Drugs Table Page 20 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Page 21 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Page 22 of 22 © 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers