Wednesday, December 7, 2016
Wisdom Wednesday: Lipid Panel Continued
This week we continue with the HDL, LDL, and triglycerides:
The HDL or high density lipoprotein laboratory range is 40-90 mg/dL while the functional range is above 55 mg/dL. It is produced in the liver and the intestines. HDL is a protein carrier which moves fats from the peripheral tissues to the liver.
HDL is often labeled as “good cholesterol” and it has a strong relationship with coronary artery disease (CAD). Levels below 25 mg/dL double the risk of CAD. Between 26-35, the risk of CAD is 50% higher. The average risk is from 45-59 and levels above that impart below average risk of CAD.
Smoking, excess weight and lack of exercise all diminish HDL levels. Typically, for every 3 pounds of weight loss, the HDL will increase by 1 mg/dL. Of note, high-fat diets consistently improve HDL levels. However, caloric restriction has been shown to lower HDL levels by 2-12 mg/dL although levels will improve again once a normal diet is resumed.
Steroids, diuretics and beta blockers all reduce HDL levels. Low HDLs are commonly seen with liver congestion or a fatty liver, high carbohydrate intake, sedentary lifestyle or exogenous estrogen use.
The LDL or low density lipoprotein is a protein carrier that moves fats from the liver to peripheral tissues. Generally, 60-70% of the total cholesterol is made up of LDL. The laboratory range is 60-130 mg/dL while the functional range is below 120. Most labs calculate the LDL rather than actually measure the level based on the ratios of the other lipids.
LDL is often mislabeled as “bad cholesterol”. It increases as carbohydrates (not fats) increase in the diet. Metabolic syndrome, liver congestion, exogenous hormones, hypothyroidism, oxidative stress and cardiovascular disease are all associated with levels over 140 mg/dL.
Levels below 100 are associated with low vitamin D levels, steroid hormone imbalanaces, hyperthyroidism, severe liver disease, chronic anemia sedentary lifestyle and, of course statin drug therapy.
The laboratory range for triglycerides is 30-150 mmol/L while the functional range is much narrower at 70-100 mmol/L. More than 90% of the total triglycerides in the body are consumed as dietary fat. They are stored as adipose tissue once the liver and muscle storage sites are full. When needed, the liver breaks down them down into glycerol and fatty acid.
Triglycerides are sensitive to the intake of dietary fat just prior to serum testing. In theory, the levels should be half of the total cholesterol if fat is being metabolized correctly.
In increase (>100) is noted with poor fat metabolism, insulin resistance, Metabolic syndrome, and Diabetes, fatty liver, hypothyroidism, atherosclerosis, a high carbohydrate diet and with the use of estrogen or oral contraceptives.
A decrease is found with insufficient fat intake, liver dysfunction, protein malnutrition, vegetarian diet, hyperthyroidism, autoimmune disease, hypochlorhydria and hyperlipidemia.
If the triglycerides are above 400, it renders the rest of the lipid panel invalid as it distorts the spectrographic readings for cholesterol and HDL.
The Bottom Line:
The HDL, LDL and triglycerides add valuable information to the total cholesterol. Most often it is the high carbohydrate intake that skews these numbers. Don’t believe that the lower the total cholesterol and LDL levels, the better. Cholesterol metabolism is vital to our health especially for the production of sex hormones.