CORONARY HEART DISEASE The Relationship between Plant Sterols Intake and Total Blood Cholesterol Level in Bogor Rural Area

4 Coronary heart disease is caused by interaction or reinforcement of multiple risk factors Kusmana 1996. Risk factors are characteristics associated with the occurrence of a particular disease or a condition that can cause a disease Kusmana Hanafi 1996; Frayn Stanner 2005. This term includes lifestyle risk factors that can be modified such as lifestyle and diet, biochemical and physiological characteristics, and individual characteristics that cannot be modified such as age, gender, and family history of the disease Frayn Stanner 2005. There are several factors for coronary heart disease consists of unmodifiable and modifiable factors. National Cholesterol Education Program 2002 divides the factors the unmodifiable factors into increasing age, gender men are more at risk, and a family history of heart disease. Meanwhile, the other type of risk factor consists of high low density lipoprotein LDL cholesterol, low high density lipoprotein HDL cholesterol, hypertension, diabetes, obesity, physical inactivity, smoking, atherogenic diet high intake of saturated fat and low intake of vegetables, fruits, and whole cereals. Thom et al. 2006 in DeBruyne, Pinna, Whitney 2008 showed that about 90 of patients with CHD have at least one of four classical risk factors; smoking, high LDL cholesterol, high blood pressure, and diabetes. Meanwhile, Mann and Truswell 2002 added that psychosocial factors include lower socioeconomic classes, stressful situations, and unhealthy behaviors as well as geographical factors include climate and cold air also increases the risk of coronary heart disease. The modifiable factors of coronary heart disease are highly related to diet and lifestyle. Mann and Truswell 2002 stated that vegetarians have lower risk of CHD than meat eaters, although further research still required. High salt intake can also increase the risk of high blood pressure affecting the higher risk of coronary heart disease DeBruyne, Pinna, Whitney 2008. Obesity, overweight condition characterized by body mass index over 30, is the biggest risk factor resulting from perennially improper diet. Some risk factors for coronary heart disease is shown in Table 1. Table 1. Risk factors for coronary heart disease Clinical Measures Modifiable by Dietary Factors Direct of Association Relevance to Coronary Heart Disease Age No Increases with age Increased prevalence as population ages Gender No Males at higher risk Risk in men and women is equalized after the menopause, possibly due to protection by estrogens in younger women Socioeconomic status No Lower socioeconomic status increases risk Highly related to other factors e.g. diet, smoking, physical inactivity Smoking No Smoking increases risk Increases oxidative stress and impairs endothelial function Total blood cholesterol Yes Higher level increases risk Uptake of cholesterol by macrophages is the origin of the core of the atherosclerotic plaque LDL cholesterol Yes Higher level increases risk LDL particles carry cholesterol that may be deposited in arterial wall HDL cholesterol Yes Lower level increases risk HDL may transport excess cholesterol to liver for excretion Triglycerides level Yes Higher level increases risk Inversely related to HDL cholesterol Body Mass Index Yes Overweight and obesity increase risk Increases risk partly via other factors e.g. blood pressure, smoking, diabetes Blood pressure Yes Higher pressure increases risk Hypertension induces endothelial dysfunction and exacerbates atherosclerotic process Source: Frayn and Stanner 2005 5 There are also several have clinical data that can be used to predict whether a person has a high risk of coronary heart disease NCEP 2002. Table 2 shows several types of clinical measurements of coronary heart disease risk. Table 2. Clinical measures to assess the risk of coronary heart disease Clinical Measures Desirable Borderline Risk High Risk Total blood cholesterol mgdL 200 200 – 239 ≥ 240 LDL cholesterol mgdL 100 130 – 159 160 – 189 HDL cholesterol mgdL ≥ 60 59 – 40 40 Triglycerides, fasting mgdL 150 150 – 199 200 – 499 Body Mass Index BMI 18,5 – 24,9 25 – 29,9 ≥ 30 Blood pressure systolicdiastolic 120 80 120-13980-89 ≥ 140 ≥ 90 Source: National Cholesterol Education Program 2002

B. CHOLESTEROL

Cholesterol is a hydrophobic natural chemical compound and is the main type of sterols in animals especially mammals Parish et al. 2002 in Akoh Min 2002. Despite the opinion to be harmful compounds to health, cholesterol is substantial as the precursor for steroid hormones biosynthesis such as progesterone, glucocorticoids, mineral corticoid, androgens, and estrogens. Cholesterol also plays an important role to the biosynthesis of bile acids and vitamin D Harper et al. 1988; Clarenburg 2001. Moreover, Clarenburg 2001 revealed that cholesterol also regulates the permeability of the membrane and maintain the integrity of the cells throughout the body to prevent excessive water evaporation through the skin. Cholesterol is not an essential substance for the body because it can be made endogenously by the body DeBruyne, Pinna, Whitney 2008. Endogenous cholesterol formation occurs primarily in the liver Harper et al. 1988; Cheung et al. 1993. After synthesized in the liver, cholesterol and the other fats are transported in the form of lipoproteins to be stored in the tissue. Lipoprotein is a combination of the triglycerides and other lipids such as cholesterol and phospholipids with specific proteins Almatsier 2003. Briefly, there are two main types of lipoproteins with different characteristics,

1. Beta lipoprotein-low density lipoprotein LDL

This type of lipoprotein carries fat and cholesterol in high amount from liver to the body cells and tissues. LDL is often referred as “bad cholesterol”, despite the fact that it is actually a lipoprotein, because it holds high amount of cholesterol and could easily slip into epithelium wall in blood vessel and oxidized Almatsier 2003. The oxidation of LDL cholesterol would have a chain reaction resulted in a buildup inside the blood vessels and form plaques, leading to atherosclerosis and coronary heart disease. 6

2. Beta lipoprotein-high density lipoprotein HDL

HDL is produced separately in the liver and in charge of bringing back excess cholesterol from body cell to liver in order to be excreted Almatsier 2003. As the lower cholesterol content and cholesterol disposal function, HDL cholesterol is often called as the good cholesterol. Although cholesterol is sufficient from endogenous biosynthesis, dietary cholesterol also contributes to the so-called exogenous cholesterol. Exogenous cholesterol is cholesterol obtained from the gastrointestinal absorption of the food consumed. Increased consumption of dietary cholesterol by 200-750 mg will increase blood cholesterol levels as much as 5.4 - 5.8 mmolL Bender 2000. Most of the cholesterol in the blood comes from the synthesis in the body which is about 1 gday and 0.3 gday from food Harper et al. 1988; Clarenburg 2001; Bachorik et al. 2001. Total blood cholesterol can be measured through several ways; either a complete blood test performed by medical professional or by using cholesterol home test kit. The examples of cholesterol home test kit can be seen in Figure 2. Although the test is not able to identify the levels of each of the components such as LDL or HDL cholesterol accurately and the variability of result may be higher than complete blood test, the American Heart Association 2010 stated that the measurement is considerably useful to screen the risk of developing cardiovascular disease. However, to determine the levels of each composition of blood cholesterol and triglyceride, it is preferable to do complete blood test performed by medical professional. Figure 2. Example of commercially available cholesterol home test kit http:www.priceinspector.co.uk

C. PLANT STEROLS

Plant sterols PS are plant compounds with similar structure and biological functions as cholesterol Parish et al. 2002 in Akoh Min 2002. The differences of these two types of sterols are located on the side chain configuration and the degree of saturation Clifton 2002. More than 250 types of plant sterols have been isolated from plants Piironen et al. 2000. Piironen further explained that the most common types of plant sterols found in plants are β-sitosterol, campesterol, and stigmasterol. Β-sitosterol is the most dominant type of plant sterols, constitutes of 56-79 of the plant sterols total consumption. Sitosterol is used to synthesize steroid sitosterol. Meanwhile, campesterol and stigmasterol has a proportion of 18 and 9, respectively. Saturated plant sterols derivatives, which are less abundant in nature, are called plant stanols. Plant stanols constitutes about