Factors leading to coronary heart disease (CHD)

What is CHD?

Figure 1- Image showing the location of the coronary
arteries and comparing a normal coronary artery
to one narrowed by atherosclerosis

Coronary Heart Disease is when our coronary arteries (arteries that supply our heart muscle with oxygen-rich blood) become more narrow due to a gradual build-up of fatty material within their walls (Figure 1). This condition is known as atherosclerosis and the fatty material is known as atheroma. Atheroma is also referred to as plaque.
Over time, our arteries can become so narrow that not enough oxygen-rich blood can flow through them to the heart. As a result, we can feel pain and discomfort called angina. On the other hand, if a piece of atheroma breaks off, a blood clot can form, blocking blood flow.

How does CHD develop?

From a young age, cholesterol-loaded plaque can start to deposit in the blood vessel walls. As we get older, the plaque builds up and results in the inflammation of the blood vessel walls as well as a higher risk of blood clots and heart attacks. The plaques release chemicals that encourage the process of healing but cause the inner walls of the blood vessels to be sticky. Other substances such as inflammatory cells, lipoproteins, and calcium then travel through our bloodstream and start sticking to the inside of the vessel walls.
Eventually, it is possible for a narrowed coronary artery to develop new blood vessels that form around the blockage to get blood to the heart. Even so, during times of increased stress or exercise, the new arteries may not be able to supply sufficient oxygen-rich blood to the heart muscle.

Causes of CHD

As well as the gradual build-up of atheroma, there are factors that can increase the risk of developing atherosclerosis. These include:

• Smoking- The chemicals in tobacco smoke harm our blood cells. They can damage the function of our heart and the structure and function of our blood vessels, therefore increasing our risk of atherosclerosis

• High blood pressure (hypertension)- Hypertension stresses our body's blood vessels causing them to clog and weaken. Additionally, it can lead to atherosclerosis and narrowing of the blood vessels making them more likely to block from blood clots. 

• High blood cholesterol level- When there is too much cholesterol in our blood, it builds up in the walls of our arteries, causing atherosclerosis. 

• Lack of regular exercise- Exercise increases circulation and helps clear arteries. Lack of regular exercise prevents this circulation and cleanup of arteries, increasing our risk of developing CHD.  

• Diabetes- High blood sugar levels increase the chance of buildup of plaque in our arteries, therefore leading to CHD.

• Obesity- Obesity leads to high blood pressure, high blood cholesterol, and diabetes, all of which increase our risk of CHD. 

• Family history of CHD

Preventing CHD

There are multiple ways of lowering the risk of developing CHD. Firstly, it is important to take into consideration the factors that increase the risk and prevent these. For example, it is important to regularly exercise, maintain a normal blood cholesterol level as well as a normal blood pressure, etc... Factors decreasing the risk of CHD include:

• Eating a healthy, balance diet- According to nhs.uk, it is recommended to eat a low-fat, high-fibre diet which should include a large amount of fruit and vegetables and whole grains. The amount of salt in the diet should be limited as too much salt will increase blood pressure. There are two types of fat: saturated and unsaturated. It is recommended to avoid saturated fats because they will increase the levels of bad cholesterol in our blood. As seen in Figure 2, sausages, butter, cream, cakes and biscuits are example of foods containing saturated fats. A balanced diet should include unsaturated fats which are found in nuts, seeds, avocados, and oily fish. 

• Reduce alcohol consumption

• Take prescribed medication

Figure 2- Foods containing unsaturated fats vs saturated fats 

Bibliography:

"Coronary Heart Disease - Causes ." Coronary Heart Disease. N.p., n.d. Web. 22 Jan. 2016.

"Hypertension." Cardiovascular Disease Risk Factors -. N.p., n.d. Web. 22 Jan. 2016.

"Cholesterol and Heart Disease." WebMD. WebMD, n.d. Web. 22 Jan. 2016.

"How Lack of Exercise Causes Heart Disease." LIVESTRONG.COM. LIVESTRONG.COM, 30 Oct. 2015. Web. 22 Jan. 2016.