Cholesterol

Introduction

Classification

Food sources of cholesterol - chart

Interpreting of cholesterol numbers

Combating high cholesterol

Introduction

 
   Just at the beginning of the 20th century the link between circulatory system diseases and cholesterol was discovered. Increased concentration of "bad" cholesterol and free triglycerides in blood plasma belongs to the most important factors of arteriosclerosis hazard. When blood freely flows through blood vessels, together with it nutritious substances and essential to life oxygen are provided to every single cell. In blood also circulate compounds which may damage our arteries from inside (e.g. free radicals). Formed in this way damages cause that in these places fatty substances (mainly cholesterol) and thrombocytes begin to settle. Banks, which obstruct blood flow to many organs, are formed. In that way little and little oxygen reaches organs and progressive hypoxemia of organs leads to their insufficiency. Usually narrowing does not cover all arteries, it occurs in particular sections. Most frequently it concerns coronary arteries which conduct blood to heart. But one should remember cholesterol is also a forerunner of many important, essential for right organism functioning compounds which are sex hormones, hormones of adrenal cortex, vitamin D, gall acids.

Classification

• HDL - "good cholesterol"

• LDL - "bad cholesterol"

• IDL

• VLDL

• Chylomicrons

HDL - "good cholesterol"
   
   Lipoproteins of high density. HDL contains approximately 55% protein, 3-15% triglycerides, 26-46% phospholipids, 15-30% cholesteryl esters, and 2-10% cholesterol. High density lipoproteins are the smallest of the lipoproteins. HDL particles have a size of 6-12.5 nanometers and a density of ~1.12. They decrease the total level of cholesterol in blood by its transport to liver, where it is expelled - that is why they act positively, slowing down the growth of vessel arteriosclerosis. HDL (High Density Lipoproteins) collects redundant cholesterol and carries it back to liver to be processed by organism. It can also remove cholesterol accumulated in arteries what means arteriosclerosis moving back.

LDL - "bad cholesterol"
  
   Lipoproteins of low density. LDL contains 20-22% protein, 10-15% triglycerides, 20-28% phospholipids, 37-48% cholesteryl esters, and 8-10% cholesterol. Low density lipoproteins are smaller than IDL, approximately 26 nanometers, and have a density of ~1.04. They increase cholesterol level in blood by its transport from liver to tissues - that is why they accelerate the grow of arteriosclerosis. Higher LDL (Low Density Lipoproteins) cholesterol level increases heart disease hazard because this form of cholesterol settles on arterial walls. To reduce the level of this fraction one should limit the consumption of saturated fatty acids and trans isomers (products originated from animals e.g. meat, butter, full fat milk, hydrogenated margarines, pastries, French fries, chips), increase consumption of food containing soluble fiber, keep the right body mass.

IDL
   
   Lipoproteins of intermediate density. These kind of lipoproteins are smaller than VLDL, approximately 40 nanometers, and have a density of ~1.0. Their function is to transport endogenous fats and cholesterol from liver to tissues. IDLs are composed of 10-12% protein, 24-30% triglycerides, 25-27% phospholipids, 32-35% cholesteryl esters and 8-10% cholesterol. IDLs are derived from VLDL by triglyceride depletion and therefore contain the same apolipoproteins as VLDL. IDL becomes LDL as its triglycerides are transferred to the cells.

VLDL
   
   Lipoproteins of very low density. Very low density lipoproteins are approximately 25-90 nanometers in size, and have a density of ~0.98. Their function is to transport endogenous fats and cholesterol from liver to tissues. VLDL contains 5-12% protein, 50-55% triglycerides, 18-20% phospholipids, 12-15% cholesteryl esters and 8-10% cholesterol. VLDL also acquires several apolipoproteins from plasma HDL and is a source of triglycerides for the cells.

Chylomicrons
   
   Chylomicrons are the largest and least dense of the lipoproteins. These 1000-nanometer in size, and have a density of less than 0.95. Their function is to transport dietary fats and cholesterol from intestines to tissues. Chylomicrons contain about 1-2% protein, 85-88% triglycerides, ~8% phospholipids, ~3% cholesteryl esters and ~1% cholesterol. The lymphatic system transports chylomicrons to the plasma where they acquire additional apolipoproteins from HDL. Triglycerides contained in chylomicrons are hydrolyzed in the tissues and the particle remnants are processed by the liver.

Food sources of cholesterol - chart

 
   Dietary cholesterol is found only in foods derived from animals (meat, fish, poultry, eggs and dairy products), it is not present in plants. Too high "bad cholesterol" content in a diet may increase the level of this ingredient in blood serum, although some people possess increased "combustion" of cholesterol coming from food of animal origin. For the rest one of protective action is limitation of daily cholesterol consumption. The safe range of cholesterol intake is: 200-400 milligrams per day.

Interpreting of cholesterol numbers

 
The right concentration in blood of the adults:

• Total cholesterol [mg/dl]
  desirable: below 200
  borderline: 201-239
  undesirable: 240 and above




• LDL cholesterol ("bad cholesterol") [mg/dl]
  desirable: below 130
  borderline: 131-159
  undesirable: 160 and above




• HDL cholesterol ("good cholesterol") [mg/dl]
  desirable: above 45
  borderline: 41-45
  undesirable: below 40




• Triglycerides (Tryglicerydes) [mg/dl]
  desirable: below 150
  borderline: 151-199
  undesirable: above 200

   Having elevated triglycerides may also increase the risk of heart disease. The same factors like in the case of cholesterol (exercises, a good diet, and correct weight) can decrease triglycerides.

Combating high cholesterol

 
   Many factors  such as genetics, weight, lack of activity (exercises) and poor diet contribute to high cholesterol. Understanding how these factors affect your cholesterol is important in the prevention and treatment of high cholesterol. 

Genetics
    Just as some people inherit physical characteristics from their parents, others inherit an increased likelihood of developing high cholesterol. If you have a family history of heart disease or high cholesterol, it is important to focus on those aspects which you can control rather than feeling genetically doomed. By maintaining a healthy weight, exercising regularly and eating a low-fat, well-balanced diet you will decrease your chances of developing heart disease.

Weight
    Accumulating excess weight is generally associated with increased total and LDL cholesterol. Every individual responds differently to weight loss, however most people find that blood cholesterol drops as weight decreases. The best way to lose weight and lower cholesterol is through increased activity coupled with low-fat eating.

Exercise
    Exercise is very important in controlling cholesterol levels. Not only does total and LDL cholesterol tend to decrease with activity, but HDL cholesterol increases. In order to get this effect "aerobic" activity is best. Aerobic exercise is any exercise that is continuous, rhythmical and involves large muscle groups. Most aerobic exercise end with the letter "ing" (walking, running, rowing, cycling, swimming, rope skipping, dancing, hiking, and skating). The cholesterol lowering effect of exercise is greatest when individuals exercise at least 3 times per week for 30 minutes or more. 

Diet
    Diet is also a major component of decreasing blood cholesterol. A proper diet can help lower cholesterol for several reasons. Diet modifications are essential for weight loss but can effect cholesterol levels even if weight remains unchanged. Also, a proper diet is essential to provide energy for those engaging in daily aerobic exercise. Fat is often targeted as the main dietary factor which affects blood cholesterol. Fat serves many functions in the body therefore, a fat free diet is not a healthy diet. However, the amount and type of fat in the diet is important in controlling cholesterol. Other dietary suggestions

• dietary fiber binds cholesterol and can help in cholesterol reduction. Choosing whole grain products (bran cereal, whole wheat bread) as well as fresh fruits and vegetables will increase dietary fiber intake,

• read food labels. Food labels are required to list ingredients as well as the amount of fat, saturated fat and cholesterol in the food. Reading food labels will allow you to choose heart healthy foods,

• select protein sources from: fish which contains omega-3 fatty acids and can be helpful in reducing the risk of heart disease lean cuts of meat (trim visible fats and look for little marbling), skinless poultry, cooked dry beans and legumes, eggs (limit 3-4 per week).

   In case of increased cholesterol and triglyceride concentration in blood the application of efficient low - cholesterol diet is important.