What is cholesterol?
"Bad cholesterol" and "good cholesterol"... what's that?
Cholesterol is a fatty substance found in the blood of humans and also in the outer lining of cells (membrane) in the body of animals. The cholesterol that we have in our blood comes from two different sources:
- liver production
- diet: meat, fish, dairy products
After a meal, cholesterol is absorbed by the intestines, goes into the blood and then it's packeged inside a protein coat. These proteins are removed then by the liver.
When you go to the doctor, you are suggested to keep the "bad cholesterol" in blood low and the "good cholesterol" high. Ok. What does this mean?
- Bad cholesterol or LDL-low-density lipoprotein: These proteins deposit cholesterol on the artery walls, causing the formation of a hard substance named "cholesterol plaque". With the time, this plaque leds to narrowing of the arteries in a process called atherosclerosis. Because of this, the arteries can get blocked, so LDL is associated with a higher riks of coronary heart diseases.
When the liver has many LDL receptors, this helps to remove more rapidly the LDL cholesterol from the blood, helping to keep the bad cholesterol levels low. The number of LDL receptors depends on both heredity and diet. For instance, people with familial hypercholesterolemia have a very low number of LDL receptors, so they usually have high levels of bad cholesterol. Besides, the bad cholesterol level can raise with diets high in saturated fats (certain vegetable oils and products derived mainly from meat and dairy products).
- Good cholesterol or HDL-high-density lipoprotein: These particles extract cholesterol from the artery walls and dispose them through the liver. So they prevent atherosclerosis.
Life style factors and other conditions influence HDL cholesterol levels. HDL cholesterol levels are for instance lower in smokers, people who eat a lot of sweets, and also in those who are overweight and inactive. On the other hand, estrogen increases the HDL cholesterol level, so usually women have higher good cholesterol levels than men.
These are some websites with interesting suggestions to keep your cholesterol at healthy levels:
- Low cholesterol diet.
- Cholesterol Lowdown.
- liver production
- diet: meat, fish, dairy products
After a meal, cholesterol is absorbed by the intestines, goes into the blood and then it's packeged inside a protein coat. These proteins are removed then by the liver.
When you go to the doctor, you are suggested to keep the "bad cholesterol" in blood low and the "good cholesterol" high. Ok. What does this mean?
- Bad cholesterol or LDL-low-density lipoprotein: These proteins deposit cholesterol on the artery walls, causing the formation of a hard substance named "cholesterol plaque". With the time, this plaque leds to narrowing of the arteries in a process called atherosclerosis. Because of this, the arteries can get blocked, so LDL is associated with a higher riks of coronary heart diseases.
When the liver has many LDL receptors, this helps to remove more rapidly the LDL cholesterol from the blood, helping to keep the bad cholesterol levels low. The number of LDL receptors depends on both heredity and diet. For instance, people with familial hypercholesterolemia have a very low number of LDL receptors, so they usually have high levels of bad cholesterol. Besides, the bad cholesterol level can raise with diets high in saturated fats (certain vegetable oils and products derived mainly from meat and dairy products).
- Good cholesterol or HDL-high-density lipoprotein: These particles extract cholesterol from the artery walls and dispose them through the liver. So they prevent atherosclerosis.
Life style factors and other conditions influence HDL cholesterol levels. HDL cholesterol levels are for instance lower in smokers, people who eat a lot of sweets, and also in those who are overweight and inactive. On the other hand, estrogen increases the HDL cholesterol level, so usually women have higher good cholesterol levels than men.
These are some websites with interesting suggestions to keep your cholesterol at healthy levels:
- Low cholesterol diet.
- Cholesterol Lowdown.
Why smoking is so harmful?
The word "tobacco" is thought to derive from the Native American word "tabago," for a Y-shaped pipe used in sniffing tobacco powder. Cigarettes and other forms of tobacco consist of dried tobacco leaves, and other ingredients added for flavor and other properties.
Some facts related with smoking:
- Smoking is the second major cause of death in the world. It's responsible for the death of one in ten adults worldwide.
- Smoking accounts for about 80-90% of all chronic obstructive pulmonary disease.
- Smoking is involved in 85% of all lung cancer deaths.
- Smoking is the major cause of cancer of the lips, tongue, mouth, pharynx, larynx and esophagus.
- Smoking has many other harmful effects in the body, a too long list to include it here.
Why smoking causes cancer? It's because tobacco and tobacco smoke contain more than 60 carcinogenic compounds. In general, more than 4,000 individual substances have been identified in tobacco smoke, including carbon monoxide, hydrogen cyanide, ammonia and other toxic irritants.
Besides all the harmful effects of tobacco, it's addictive, and this explains why although 70% of smokers want to quit and 35% attempt to quit each year, fewer than 7% succeed. The main reason why tobacco becomes addictive is due to its content of nicotine, which alters brain functioning.
Nicotine is a naturally occurring liquid alkaloid. An alkaloid is an organic compound made out of carbon, hydrogen, nitrogen and sometimes oxygen. These chemicals have potent effects on the human body. For example, many people enjoy the stimulating effects of another alkaloid, caffeine.
Some facts related with smoking:
- Smoking is the second major cause of death in the world. It's responsible for the death of one in ten adults worldwide.
- Smoking accounts for about 80-90% of all chronic obstructive pulmonary disease.
- Smoking is involved in 85% of all lung cancer deaths.
- Smoking is the major cause of cancer of the lips, tongue, mouth, pharynx, larynx and esophagus.
- Smoking has many other harmful effects in the body, a too long list to include it here.
Why smoking causes cancer? It's because tobacco and tobacco smoke contain more than 60 carcinogenic compounds. In general, more than 4,000 individual substances have been identified in tobacco smoke, including carbon monoxide, hydrogen cyanide, ammonia and other toxic irritants.
Besides all the harmful effects of tobacco, it's addictive, and this explains why although 70% of smokers want to quit and 35% attempt to quit each year, fewer than 7% succeed. The main reason why tobacco becomes addictive is due to its content of nicotine, which alters brain functioning.
Nicotine is a naturally occurring liquid alkaloid. An alkaloid is an organic compound made out of carbon, hydrogen, nitrogen and sometimes oxygen. These chemicals have potent effects on the human body. For example, many people enjoy the stimulating effects of another alkaloid, caffeine.
Nicotine:
When you smoke, nicotine is absorbed through the skin and mucosal lining of the mouth and nose or by inhalation in the lungs. Once in the body, it activates the same reward system as do other drugs such as cocaine or amphetamine, although to a lesser degree. In the brain, nicotine increases the level of the neurotransmitter dopamine, which is a chemical in the brain responsible for feelings of pleasure. The acute effects of nicotine subside within minutes, so people continue dosing themselves frequently throughout the day to maintain the pleasurable effects of nicotine and to prevent withdrawal symptoms.
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