Humans get cholesterol from the diet or they synthesize it f

Humans get cholesterol from the diet or they synthesize it from Acetyl CoA. An adult on a low cholesterol diet synthesizes around 600 mg cholesterol per day. This amount drops dramatically if the person transitions to a red- meat diet. Give a mechanistic explanation for this observation! The amount of HMG-CoA reductase can increase substantially in patients treated with statins. What might be the reason for this side effect? Why do you think some doctors suggest that patients treated with statins also take a coenzyme Q supplement? Why is a drug that prevent reuptake of bile acids often taken together with statins? How many moles of ATP are needed to synthesize one mole of lanosterol (precursor to cholesterol)? Which diet do you think make a person more prone to generate ketone bodies; a \"no-carb diet\" or a \"no-carb diet\" supplemented with glucogenic amino acids such as aspartate and valine? Justify very briefly.

Solution

1)

Cholesterol is produces in the body and also taken in diet. The cholesterol produces in live which bundles with proteins to form LDL (low density lipoprotein) in the body. The cholesterol taken in diet is HDL (high density lipoprotein). LDL and HDL are known as bad cholesterol and good cholesterol respectively. Both LDL and HDL are essential for the body. But high level of LDL is considered as bad cholesterol because it deposits in arteries to form plaques leads to clots and atherosclerosis. On another hand HDL helps in removal of bad cholesterol and reduces clots and decreases the cardiovascular problems (heart diseases). HDL removes excess of cholesterol from blood stream and takes it back to live where it’s broken down and removed from body. Red meat is good source of HDL that’s why increase in red meat diet lowers bad cholesterol from the body.

2) HMG-CoA reductase is an enzyme of mevalonate pathway which produces cholesterol in the body. Statin is an inhibitor of the enzyme HMG-CoA reductase and helps in lowering the cholesterol production. Statin is found good in lowering heart diseases and used to treat hypercholesterolemia but has various side effects like muscle pain, diabetes mellitus, muscle damage etc.

3) Human body makes Co-enzyme Q naturally which plays important roles such as muscle cell energy production and also acts as antioxidant. Co enzyme Q is universally recommended for preventing side effects of drugs such as statin or other cholesterol-lowering drugs. But statin has been observed in reducing natural body Co enzyme Q. Therefore to full fill the necessary requirement of Co enzyme Q, its supplementation is recommended.

4) Bile acids are steroid acids found in the bile of mammals. Bile salts digest various lipids in intestine and recirculate them back to liver to make other lipid molecules like cholesterol. And more cholesterol production may revert the action of statin (decreasing cholesterol). Therefore the drugs preventing bile acids often recommended with statin.