2016년 9월 1일 목요일

High-fat diet leads to Coronary Heart Disease. Discuss.

 

           A high-fat diet, and coronary heart disease. It seems like the liver takes no part in these two events. However, coronary heart disease is actually closely related to the function of the liver.

           Liver, the largest organ in the human body which consists 3-5% of the body weight, is one of the most vital organs that carries out numerous pivotal functions. To name a few, Kupffer cells in sinusoid of the liver break down erythrocytes (which has a lifespan of approximately 120 days), detoxify toxic substances in our body (alcohol detoxified by enzyme alcohol dehydrogenase), store excess glucose in our body in the form of glycogen using insulin produced by beta-islets of Langerhans, and produce plasma proteins. The function of the liver that is highly linked to coronary heart disease, however, is regulation of lipids.

           These lipids include cholesterol or lipoproteins. The recent research classifies High-Density Lipoprotein (HDL) as a ‘good’ cholesterol and Low-Density Lipoprotein (LDL) as a ‘bad’ cholesterol. The difference between them is the proportion of lipid to protein. HDL contains a higher proportion of ‘healthy’ protein than LDL does. Whenever lipid level gets too high in our body, hepatocytes synthesise those into cholesterol for internal usage. This process includes synthesis of vitamin D, steroid hormones, bile production, and cell membrane construction.

           When a person intakes an excess amount of lipids (high saturated fat diet), then all of the cholesterol processing mechanisms produce much more cholesterol than our body requires. Since there is a point when no more vitamin D, steroid hormones, bile salts, or new cell membrane construction is necessary, no more cholesterol, produced by hepatocytes, can be utilised for essential purposes, hence leaving the excess amount of ‘bad’ low-density lipoproteins in the bloodstream. This cholesterol eventually accumulates underneath the endothelium layer of the blood vessels, which leads to the swollen inner wall and narrower lumen. This phenomenon is called atherosclerosis.

           When the lumen gets narrower, the blood pressure drastically increases as well and therefore leads to rupture of endothelium. Naturally, by the sequence of cascade reaction of some of the plasma proteins (platelets -> prothrombin to thrombin -> fibrinogen to fibrin), blood clot forms on the inner wall of the blood vessel. This process is called coronary thrombosis.

           When these blood clots detach from the endothelium and swim around the bloodstream, the situation gets serious. When solid blood clots move around the circulatory system and end up stuck in an extremely narrow coronary artery (a crucial artery used to supply oxygen for myogenic contraction of the heart muscle), oxygen supply for the heart is halted, leading to the ceasing of the heart’s ‘blood-pumping’ activity. This can ultimately cause an array of coronary heart diseases (CHD) and can be expressed by treacherous symptoms such as myocardial infarction.

           To conclude, for the following reasons and phenomena stated above, the idea that high-fat diet leads to coronary heart disease is categorically true.
 

댓글 6개:

  1. WWW: Explains well in detail how LDL relating to the function of the liver and how CHD is caused as far as the role of liver during the process is concerned.

    EBI: It would have been even better if you focused more on and referred back to the topic about the relationship between high fat diet and CHD

    Q1> Could you elaborate more on the point that the idea that high fat diet leads to CHD is 'categorically true'?

    Q2> Could you explain what myocardial infraction is?

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    답글
    1. Q1> High Fat -> Increase in Low-Density Cholesterol -> Artherosclerosis -> Coronary Thrombosis -> CHD

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    2. Q2> Myocardial infarction is a common type of CHD which happens when coronary artery is blocked and no more nutrients and oxygen can be supplied to the heart muscle

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  2. What went well: Details in how the funtion of liver is related to CHD
    Even better if : Include some other risk factors that cause CHD
    Questions:
    How does consumption of high fat diet direclty links to the cause of CHD?

    You said "the idea that high-fat diet leads to coronary heart disease is categorically true", but waht about formation of HDL? Isn't this also caused by consumption of food? Do you think all types of fat contribute the same to the cause of the disease?

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  3. HDL, as already explained, is not a harmful cholesterol. HDL is also formed by consumption of food, but it is used in many useful ways such as cell membrane formation. To conclude, HDL does not contribute to CHD at all. It is LDL which does all does kind of nasty job.

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  4. Word Count: 492
    Originality: 100%

    This is an interesting article and I like the way to point to the liver as a key organ the mediates between our diet and our cardiovascular health. You have not, though, discussed much about the diets other than high cholesterol diets affect our health. Nor have you provided an evidence of your sources.

    A number of people have picked up on your statement that a high fat diet leads to CHD is 'categorically true'. It would appear clear that you firmly believe this to be the case, however, there is evidence that castes doubt on this notion, and as such I believe that we should all (as scientists) avoid such absolute conclusions unless we can provide irrefutable evidence to the contrary. Nonetheless, this is a well written article.

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