Cholesterol Levels
Cholesterol is ubiquitous in animal-based diets and animal cells. It is manufactured in the liver (about 80%) and the digestive tracts (the 20% are from foods we eat). It is a powdery, white, and water-insoluble. Because of this characteristic, it needs a transporting vehicle like lipoproteins. Lipoproteins are spheres of protein and lipids.
There are two main types of lipoprotein transporter: HDL (high-density lipoproteins) and LDL (low-density lipoproteins)
Cholesterol per se is not deleterious to our health. Despite the bad press of cholesterol, it is actually vital in many cellular activities. Generally, cholesterols are needed in building and maintaining membranes’ fluidity. They reduces the permeability of plasma membrane from hydrogen ion (hydrogen is responsible for the acidity in a substance) and sodium ions.
Cholesterol is also responsible for intracellular transport, nerve conduction and cell signaling. In the brain cells, the myelin sheath of neurons is rich in cholesterol. It also provides protection for better transmission of inter-neural impulses. The protection it provided is vital in storing information and in learning.
Cholesterol is needed to synthesize bile in the liver. Bile is warehoused in the gallbladder. Bile contains bile salts that act like a detergent that solubilize fats in our digestive tracts. This attribute of bile enables the absorption of fat-soluble vitamins such as vitamin A, E, D, and K. Synthesis of vitamin D on the skin also needs cholesterol. Production of sex hormones such as estrogen, progesterone, and testosterone also necessitates cholesterol. Steroid hormones such as cortisol and aldosterone of the adrenal gland require cholesterol for their production as well.
HDL and LDL
The ratio of protein and fat in a lipoprotein determines its density. The less protein present in a lipoprotein and more fat, the less dense it is. Hence, Low Density Lipoprotein is aptly named for its fattiness. Conversely, when more protein and less fats is present in a lipoprotein, it is high in density. Hence, High Density Lipoprotein is also classified because it is less fatty. The major difference between these two lipoproteins is their apolipoprotein.
Just what is apoliprotein? Now imagine a post office. If lipoproteins are mails, they contain ‘molecular’ addresses to where they should be delivered. These addresses are scientifically called apolipoproteins. These apoliproproteins regulate the start and the endpoint of the transportation of cholesterol. HDL and LDL basically differ in their ‘addresses’.
LDL is responsible of transporting 75% of cholesterol in the blood throughout the body. If the cells in the body need cholesterol, they will take LDL up from the bloodstream. If there is no need, the LDL will remain in the bloodstream. To avoid too much LDL in the bloodstream and cells, this is where HDL comes in. HDL serves as the janitor. HDL gathers excess LDL and returns it to the liver. In principle, the more HDL an individual has, the lower their LDL should be.
Healthy Cholesterol Level
Normally, about 150 grams of cholesterol is present in a healthy body. Most of these cholesterols can be found in the membranes. Less than 200 mg/dl is in the blood. The numbers may vary subject to health, diet, and body size. One thing to remember about cholesterol is that is it recycled by the body. Normally, 50% of cholesterol is reabsorbed in the small bowel into the bloodstream again. With this statistics, only 1 gram or 1000 mg of cholesterol is manufactured in a day. Meat eaters have a higher synthesis of cholesterol from the food they eat compared to vegetarian.
There is an issue of an ideal HDL and LDL ratio. LDL sometimes go through a process called oxidation. There are three outcomes once LDL is oxidized. First, LDL becomes an unstable molecule. This causes our body to discharge immune factors as a response to the oxidation. Despite the immune factors’ good intention, this defense mechanism can also undermine our health. Over-abundance of immune factors can cause inflammation and damage arterial wall.
Second, oxidized LDL can penetrate the arterial wall and become a plaque. These plaques can lead to blockage of arteries. Third, oxidized LDL can lower the nitric oxide level. This can prevent the blood from flowing freely. Needless to say, oxidation of LDL is deleterious to health. Arterial heart diseases can result. It is then prudent not only to avoid lifestyle that leads to oxidation of LDL but also to keep LDL number in check and increase the HDL level.
How to Measure Healthy Cholesterol Level
Blood tests can quantify both HDL and general cholesterol levels with no trouble. It is very tough to quantify LDL levels alone, but it can be computed in relation to HDL and triglyceride (fatty substance) levels from the overall level of cholesterol. The formula is:
LDL = TOTAL CHOLESTEROL – HDL – TRIGLYCERIDES/5.
Experts further created a computation scheme to determine if a person is at risk in developing heart diseases due to HDL and LDL ratio. This is done by dividing the overall cholesterol by either total LDL or HDL.
To elaborate it better, let’s do a simple arithmetic. If an individual, say Peter, has a total cholesterol of 280mg/dl and HDL of 70 mg/dL, the ratio is 4. This ratio result is a good way to prognosticate his chance of developing a heart disease depending on the ratio.
- 3.5 or below is the ideal ratio
- 4.5 means average risk
- 5 or higher means the individual is high risk
Based on this result and the experts interpretation, Peter has an above the ideal ratio of HDL vs LDL ratio and is at risk of developing a coronary heart disease. Experts say that this ratio is more accurate in predicting coronary heart diseases than determining cholesterol levels only. They fervently advocate that people should lower LDL to the ideal level to avoid heart disease development.
Elimination of Excess cholesterol
Unlike amino acids, fatty acids, nucleic acids, or sugar, the cholesterol cannot be broken down. The acids and sugars not only are broken down further but they can also be converted to ammonia, water, and carbon dioxide through chemical processes. With cholesterol, however, this is not possible. The only way to eliminate a cholesterol is through a stool (when it is temporarily deposited in the large intestines). This is in the form of bile acid and cholesterol molecules. Dietary fiber is indispensable in the elimination process of cholesterol.
