DIET THERAPY FOR HYPERLIPIDEMIAS

DIET THERAPY FOR HYPERLIPIDEMIAS
Hyperlipidemia refers to an elevation of the blood lipids, and includes cholesterol, triglycerides, or elevation of specific lipoproteins.
Hypercholesterolemia refers to an elevation in the serum level of cholesterol, while hypertriglyceridemia is an elevation of serum triglycerides.
Hyperlipoproteinemia refers to the elevation in the serum level of one or more of the lipoproteins. The lipoproteins are the means by which insoluble fats are carried in the blood stream. They fall into four groups:
1. Chylomicrons: the form carried in the lymph and blood 1 to 8 hours after a meal; contain triglycerides attached to a very small amount of protein; they give a milky appearance to the blood serum.
2. Very low-density lipoproteins (VLDL) or prebeta-lipoproteins: consist chiefly of triglycerides synthesized in the body and attached to some protein; carry a small amount of cholesterol.
3. Low-density lipoproteins (LDL) or beta-lipoproteins: derived chiefly from the prebeta-lipoproteins; account for most of the cholesterol in the circulation.
4. High-density lipoproteins (HDL) or alpha-lipoproteins: contain the largest percentage of protein, and about one fourth of the cholesterol in the circulation.
The level of the first three groups in the blood is affected by the amount and kinds of fat in the diet, while that of the high-density lipoproteins remains relatively constant. Based upon the amounts of triglycerides, cholesterol, and specific lipoproteins, Fredrickson and his associates have classified hyperlipoproteinemias into five types. A physician makes a diagnosis and prescribes appropriate diet and other therapy depending upon the medical history, the physical examination, and the laboratory findings. Some of the characteristics of each type are included in the following outline.
Type I
Inability to clear chylomicrons from plasma because of deficiency of enzyme lipoprotein lipase; triglycerides very high; cholesterol normal or elevated
Rare; usually familial; children or young adults
Abdominal pain with fat ingestion; pancreatitis; xanthomas; enlarged spleen and liver
Type II a
Elevated betalipoproteins; elevated cholesterol; normal triglycerides. Must differentiate between cholesterol present in low and high density lipoproteins; excess cholesterol in low density lipoproteins is harmful while that in high density lipoproteins may be protective
Common at all ages; often familial (probably autosomal dominant); may be secondary to excessive cholesterol intake, nephrosis, liver disease, myxedema, myeloma Xanthomas and vascular disease often in early adulthood; corneal arcus; early incidence of ischemic heart disease
Type II b
Elevated betalipoproteins, cholesterol, and triglycerides
Common; may be familial
Sensitive to caloric intake
Type III
Abnormal form of betalipoproteins determined by laboratory analysis; elevated cholesterol and triglycerides
Relatively uncommon; usually familial (recessive)
Tuboeruptive lesions of elbows, knees, buttocks; palmar xanthomas; increased incidence of coronary and peripheral vessel disease at an early age
Type IV
Increase in endogenous triglycerides (prebeta or very low density lipoproteins); cholesterol normal or slightly high; about half have abnormal glucose tolerance; some have elevated uric acid
Very common; usually found after second decade; may be familial; often secondary to diabetes mellitus
Few external signs; xanthomas if triglycerides very high; associated with early atherosclerosis and vascular disease; exacerbated by obesity
Type V
Extremely high triglyceride levels originating from chylomicrons (exogenous triglycerides) and prebetalipoproteins (endogenous triglycerides); cholesterol level somewhat elevated; abnormal glucose tolerance and hyperuricemia often found
May be familial; often secondary to diabetic acidosis, nephrosis, pancreatitis, alcoholism
Intolerance to fat from the diet (exogenous) and also fat synthesized in the body (endogenous); symptoms similar to Type I, usually after age 20; abdominal pain with fat ingestion; enlargement of spleen and liver
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GENERAL HEALTH