Dyslipidemia/Abnormal Lipid Levels in Blood

Dyslipidemias are disorders of lipoprotein (a complex of lipids and proteins) metabolism, including lipoprotein overproduction and deficiency. They may occur as one or more of the following - Elevated cholesterol, Elevated Low density lipoprotein (LDL), Elevated triglyceride levels and Decreased High density lipoprotein levels (HDL). Basically it is an imbalance of the level of fats in the blood due to a several reasons.

It is closely associated with atherosclerosis and is a major causal factor in the development of ischemic diseases (restriction of blood supply to tissues).

Cholesterol is a waxy fat carried through the blood stream by lipoproteins. HDL is considered as Good Cholesterol and LDL is considered as Bad Cholesterol. Good cholesterol (HDL) is stable and carries Bad cholesterol (LDL) away from the arteries. LDL sticks to the walls of the arteries and contributes to plaque build-up. Too complex? The diagram below will make it easy for you to understand.

Image Courtesy: http://www.hyderabadendocrinology.com/content/diabetes-and-bad-cholesteroldyslipidemia

For most people, abnormal cholesterol levels are the result of an unhealthy life style – most commonly, eating a diet that is high in fat, being overweight, heavy alcohol use, lack of exercise and leading an inactive lifestyle. Also, Diabetes and an underactive thyroid gland may lead to high cholesterol levels.

Primary dyslipidemia is caused by several disorders which affect plasma lipoprotein levels by overproduction of lipoproteins and/or decreased clearence. Many medical conditions are associated with mild or even severe dyslipidemia which is referred to as secondary dyslipidemia. Secondary causes of lipoprotein abnormalities are Hypercholestrolemia (high cholesterol levels in the blood) caused due to Hypothyroidism, obstructive liver disease, Anorexia, Drugs; Hypertriglyceridemia (high triglyceride levels in the blood) caused due to Obesity, Diabetes, Pregnancy, Alcohol, stress, sepsis, glycogen storage disease,acute hepatitis and drugs; and Low HDL caused due to Type II Diabetes, Rheumatoid arthritis, Malnutrition, obesity, smoking and anabolic steroids.

These lipid abnormalities may show no symptoms sometimes and may come to notice only during a routine health check-up. A Person maybe obese or have an early onset of chest pain. Sometimes, lipid abnormalities maybe diagnosed for the first time after a person suffers a myocardial infarction or stroke. Painless nodules called ‘xanthomas’ maybe seen on tendons, elbows, which arise due to intra- or extra-cellular deposition of cholesterol.

Dyslipidemia is a major risk factor for atherosclerosis which affects the coronary, cerebral and peripheral arterial circulation. Small dense LDL is more atherogenic , it enters the vessel wall, becomes oxidised and triggers the atherosclerosis process. Clinical event caused either by occlusion or haemorrhage in the arterial supply to the CNS results in Stroke. Peripheral Artery Disease is a manifestation of atherosclerosis in which the arterial lumen of the lower extremities becomes progressively occluded by atherosclerotic plaque.

Total Cholesterol level <200mg/dL is desirable, LDL Cholesterol level <100mg/dL is optimal, HDL Cholesterol level <40 mg/dL is low and ≥60 mg/dL is high and Triglycerides level <150 mg/dL is normal.

The essential features of lifestyle approach to reduce the risk for CHD are:

• Reduce intake of saturated fats (< 7% of total calories) and cholesterol (200mg/day).
• Therapeutic options for LDL lowering such as plant stanols, sterols and increased viscous fibre.
•  Increased physical activity and weight reduction.
• In most patients Therapeutic Lifestyle Change is initiated before drug therapy.
•  In high risk patients Therapeutic Lifestyle Changes and drug therapy work simultaneously.
•  If there is no improvement in the patient by Therapeutic Lifestyle Changes then drug therapy is started.

Insulin deficiency and hyperglycemia in Type-I diabetes produces lipid abnormalities which can be corrected with insulin therapy. Type II diabetes is associated with abnormal lipid metabolism. Diabetic patients tend to have higher Triglycerides, lower HDL and similar LDL levels compared to non-diabetics. In diabetics, the relative risk of Coronary Heart Disease is increased as the LDL is present as small dense particles. Diet and exercise are the first line therapies and are used with drug therapy when necessary.

Cardiovascular Disease is the leading cause of death for patients with Chronic renal disease as dyslipidemia accelerates renal deterioration. Management of this condition involves initiation of dietary modification and drug therapy.

Most new Coronary Heart Disease events and coronary deaths occur in older persons. Therapeutic Lifestyle Change is suggested for primary prevention of Coronary Heart Disease. LDL lowering drugs can be considered in those who are at higher risk.

Dyslipidemia in children and adolescents is commonly caused by genetic disorders, obesity and adverse diet. Total cholesterol levels are generally 40mg/dl higher in adults than in childhood.

The dietary modifications for dyslipidemia include reducing the dietary intake of saturated fats, trans-fatty acids and cholesterol. Most of the fat calorie consumption should be obtained from unsaturated fatty acids. MUFA and PUFA should represent 20% and 10% respectively of daily calorie intake.

NUTRIENTS	NOTE
Carbohydrates	50-60% of total calories should come from carbohydrates. Carbohydrates intake should consist mostly of foods rich in complex carbohydrates like whole grains, fruits and vegetables. Complex carbohydrates are low in calories and contain a wide variety of vitamins and minerals.
Proteins	20-25% of total calories should come from proteins.
Fats	Total fat intake should be limited to no more than 15-20% of total daily calories.
Dietary Fibre	Daily fibre intake should be 30-40 g/day.
Plant Stanols/Sterols	Recommended for patients with high serum cholesterol, as these reduce LDL-c levels. Plant sterols are isolated from soyabean and pine tree oils and can be esterified to unsaturated fatty acids to increase lipid solubility. Plant stanols/sterol esters at dosages of 2-3g/day lower LDL-c by 6-15% with a maximum LDL lowering effect occuring with dosages of 2g/day. Dietary consumption of plant stanols or sterols can be obtained from commercially available products containing plant sterols/stanols (i.e. margarine, juices etc.)
Fruits and Vegetables	3-5 servings/day

Read more about Fats in the Nutri-knowhow column.

Post by Faiz Lahori