Facts

LDL, HDL, and Triglycerides

Fats, also called lipids, are energy-rich substances that serve as a major source of fuel for the body's metabolic processes. Fats are obtained from food or formed in the body, mostly in the liver, and can be stored in fat cells for future use. Fat cells also insulate the body from cold and help protect it from injury. Fats are essential components of cell membranes, of the myelin sheaths that surround nerve cells, and of bile.


The two major fats in the blood are cholesterol and triglyceride. The fats attach themselves to certain proteins so they can travel throughout the bloodstream; the combined fats and proteins are called lipoproteins. The major lipoproteins are chylomicrons, very low density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL).


Each type of lipoprotein serves a different purpose and is broken down and excreted in a slightly different way. For example, chylomicrons originate in the intestine and carry certain types of digested fat from the intestines into the bloodstream. A series of enzymes then remove the fat from the chylomicrons for use as energy or for storage in fat cells. Ultimately, the remaining chylomicron, stripped of much of its fat (triglyceride), is removed from the bloodstream by the liver.


The body regulates lipoprotein levels in several ways. One way is by reducing the synthesis of lipoproteins and their entry into the bloodstream. Another is by increasing or decreasing the rate at which lipoproteins are removed from the blood.


Abnormal levels of fats circulating in the bloodstream, especially cholesterol, can lead to long-term problems. The risk of having atherosclerosis and coronary artery or carotid artery disease (and therefore the risk of having a heart attack or stroke) increases as a person's total cholesterol level increases. Low cholesterol levels are therefore generally better than high ones, although extremely low cholesterol levels may not be healthy either. An ideal total cholesterol level is probably 140 to 200 milligrams of cholesterol per deciliter of blood (mg/dL) or less. The risk of a heart attack more than doubles when the total cholesterol level approaches 300 mg/dL.


Not all cholesterol increases the risk of heart disease. The cholesterol carried by LDL (the so-called bad cholesterol) increases the risk; the cholesterol carried by HDL (the so-called good cholesterol) lowers the risk and is beneficial. Ideally, LDL cholesterol levels should be below 130 mg/dL, and HDL cholesterol levels should be above 40 mg/dL. The HDL level should account for more than 25 percent of the total cholesterol. The total cholesterol level is less important as a risk factor for heart disease or strokes than the total cholesterol to HDL cholesterol ratio or the LDL to HDL ratio.


Whether high levels of triglycerides increase the risk of heart disease or strokes is uncertain. Blood levels of triglycerides above 250 mg/dL are considered abnormal, but high levels don't appear to uniformly increase the risk of atherosclerosis or coronary artery disease. However, extraordinarily high levels of triglycerides (above 800 mg/dL) may lead to pancreatitis.

High Sensitivity C-Reactive Protein

CRP is a marker of inflammation that has been shown in multiple prospective epidemiological studies to predict incident myocardial infraction, stroke, peripheral arterial disease and sudden cardiac death.


CRP levels of <1, 1 to 3, and >3mg/L correspond to low-, moderate-, and high risk groups for future cardiovascular events.


To date, over a dozen prospective epidemiological studies carried out among individuals with no prior history of cardiovascular disease demonstrate that single, non-fasting measure of CRP is a strong predictor of future vascular events.


This relationship has been consistent in the United States and Europe and in most cases is independent of age, smoking, cholesterol levels, blood pressure and diabetes.


In one recent study, CRP was strong predictor of risk even 20 years after blood samples were obtained. CRP levels minimally correlate with lipid levels of LDL or HDL.


In terms of clinical application, CRP seems to be a stronger predictor of cardiovascular events that LDL cholesterol.


CPR levels are stable for long periods of time and not affected by food intake.


Last we believe that CRP testing should be ordered along with lipid profiles to identify apparently healthy men and women at risk of developing cardiovascular events.

Homocysteine

Homocysteine is an essential intermediate amino acid which is necessary for synthesizing protein and sustaining life.


While the body requires normal levels of homocysteine to build and maintain tissues, excess levels can occur. Too much homocysteine in the blood has been found to be associated with increased risk of heart disease, stroke and blood vessel disease in men and women. The risk of heart disease increases in people with high levels of homocysteine who also smoke cigarettes and have high blood pressure.


While it is not known how homocysteine causes hardening of the arteries, some scientists think it causes damage to blood vessels, which can trigger blood clots. Studies have shown that homocysteine levels in the blood are strongly influenced by:


  • folacin (folic acid)
  • cyanocobalamin (B12)
  • pyridoxide (B 6)

Since these help breakdown homocysteine in the body, increased intake has been associated with lower levels of homocysteine in the blood.

B-Vitamins

 The B-vitamins are essential for normal metabolic functions and are necessary for the conversion of carbohydrate, protein and fat in to tissue and energy. The B-vitamins are water-soluble and therefore are not significantly stored by the body. Any excess quantities are excreted in the urine.


B-vitamins must be replenished regularly through your diet to maintain essential tissue levels. Tissue levels of these vitamins are rapidly depleted in conditions that interfere with their intake or absorption.