Chapter 8 Physical Activity and Dyslipidemia

“THEIR HEAR IS AS FAT AS GREASE.”

P S A L M S 11 9 : 7 0

 P-168  Cholesterol is a waxy substance found in all cell membranes, it is in the brain, nerves, muscle, skin, liver, intestines and heart.

 Cholesterol is need to produce many hormones, vit D, and the bile acids that help emulsify insoluble lipids (from eating foods high in sat fat) so they can be used for cellular metabolism.

 Because it is insoluble in blood, cholesterol also transports vit A & E which are also insoluble.

 Too much cholesterol in the blood contributes to atherosclerosis, the disease that hardens and blocks arteries and leads to CHD and ischemic stroke.

 Hypercholesterolemia refers to total serum cholesterol that exceeds the population average of 200 mg/dl among adults.

 Dyslipidemia refers to hypercholesterolemia or high triglycerides (a key energy store that includes fat) or both, or low levels of HDL (HDL-C) the “good” cholesterol.

 102.2 million America adults have total blood cholesterol levels of 200mg/dl and higher, which is above recommended levels. Of these, 35.7 million have 240 mg/dl or higher which is high risk for heart disease.

 Physical activity is associated with lower blood lipids, decreased LDL-C (bad cholesterol) and

increased

HDL-C---changes that can help explain part of the protective effect that physical activity confers against CVD and mortality.

 Lipoprotein fractions are very important—A low level of HDL-C (<40 mg/dl) is a major risk factor for CHD.

 In pharmacology , the

fibrates

range of metabolic are a class of disorders, mainly amphipathic carboxylic acids hypercholesterolemia (high . They are used for a cholesterol ), and are therefore hypolipidemic agents .

 High levels of LDL-C (>200 mg/dl) and triglycerides are also associated with a high risk of CHD.

 Good cholesterol, bad cholesterol, saturated fat, and unsaturated fat -- sometimes it seems like you need a program to keep track of all the fat players in the story of heart disease.

 In some ways, triglycerides are the easiest to understand. Simply put, triglycerides are fat in the blood and are used to provide energy to the body. If you have extra triglycerides, they are stored in different places in case they are needed later. High triglyceride levels have been linked to a greater chance for heart disease. Just what your triglyceride levels mean and how much lowering triglycerides reduces heart disease risk is sometimes less clear.



What Are Triglycerides? They are the most abundant lipids in the human body.

 Triglycerides are important to human life and are the main form of fat in the body. When you think of fat developing and being stored in your hips or belly, you're thinking of triglycerides. Consider these things:  Triglycerides are the end product of digesting and breaking down fats in meals. Some triglycerides are made in the body from other energy sources such as carbohydrates.

What Are Normal and High Triglyceride Levels?

The National Cholesterol Education Program sets guidelines for triglyceride levels: Normal triglycerides means there are less than 150 milligrams per deciliter (mg/dL).

Borderline high triglycerides = 150 to 199 mg/dL.

High triglycerides = 200 to 499 mg/dL.

Very high triglycerides = 500 mg/dL or higher.

High triglyceride levels may lead to heart disease, especially in people with low levels of "good" cholesterol and high levels of "bad" cholesterol, and in people with type 2 diabetes. Experts disagree, though, on just how bad of an effect high triglyceride levels by themselves have on the heart.

 Hyperlipidemia, hyperlipoproteinemia, or hyperlipidaemia (British English) involves abnormally elevated levels of any or all lipids and/or lipoproteins in the blood .

[1] It is the most common form of dyslipidemia (which also includes any decreased lipid levels).

 Lipids (fat-soluble molecules) are transported in a protein capsule . The size of that capsule, or lipoprotein , determines its density. The lipoprotein density and type of apolipoproteins it contains determines the fate of the particle and its influence on metabolism .

 Hyperlipidemias are divided in primary and secondary subtypes. Primary hyperlipidemia is usually due to genetic causes (such as a mutation in a receptor protein), while secondary hyperlipidemia arises due to other underlying causes such as factor for cardiovascular disease due to their influence on diabetes . Lipid and lipoprotein abnormalities are common in the general population, and are regarded as a modifiable risk atherosclerosis . In addition, some forms may predispose to acute pancreatitis .

Health Readings

 Total Cholesterol: (mg/dl): Optimal < 200; borderline high 200-239; high 240+.

 LDL-C: (mg/dl): Optimal <; near optimal 100-129; borderline high 130-159; high 160-189; very high 190+.

 Triglycerides; (mg/dl); Normal <150; Borderline high 150-199; high 200-499; high 500+.

 HDL-C: (mg/dl): Low <40; high 60+. Values are based on blood levels after fasting.

 Both HDL (low) and LDL (high) cholesterol are risk factors for CAD.

Magnitude of the Problem

 P-169  What are lipoproteins? Cholesterol and other fats are not soluble so they are carried in the blood by binding with proteins.



Chylomicrons

cholesterol are lipoprotein particles (1-3%) and proteins that consist of triglycerides (1-2%).

[1] They transport dietary (85-92%), lipids phospholipids in the body. Chylomicrons are one of the five major groups of lipoproteins (chylomicrons, (6-12%), from the intestines to other locations VLDL , IDL , LDL , HDL ) that enable fats and cholesterol to move within the water-based solution of the bloodstream.



Phospholipids

are a class of lipids that are a major component of all cell membranes as they can form lipid bilayers . Most phospholipids contain a diglyceride , a phosphate group , and a simple organic molecule such as choline ; one exception to this rule is sphingomyelin , which is derived from sphingosine instead of glycerol . The first phospholipid identified as such in biological tissues was lecithin , or phosphatidylcholine , in the egg yolk, by Theodore Nicolas Gobley , a French chemist and pharmacist, in 1847.  HDL’s remove cholesterol from extrahepatic (outside the liver) tissue by

Reverse Cholesterol Transport

.

HDL Structure & Function

 P-171 The majority of HDL is lecithin. Lecithin is a generic term to designate any group of yellow-brownish fatty substances occurring in animal and plant tissues composed of phosphoric acid , choline , fatty acids , glycerol , glycolipids , triglycerides , and phospholipids (e.g., phosphatidylcholine , phosphatidylethanolamine , and phosphatidylinositol ).

Lecithin was first isolated in 1846 by the French chemist and pharmacist the phosphatidylcholine léchithine.

[2] Theodore Gobley .

[1] In 1850 he named Gobley originally isolated lecithin from egg yolk —λέκιθος (lekithos) is 'egg yolk' in ancient Greek —and established the complete chemical formula of phosphatidylcholine in 1874; bile, human brain tissue, fish eggs, fish roe, and chicken and sheep brain.

[3] in between, he had demonstrated the presence of lecithin in a variety of biological matters, including venous blood, Lecithin can easily be extracted chemically (using hexane , ethanol , acetone , petroleum ether , benzene , etc.) or mechanically. It is usually available from sources such as soy beans, eggs, milk, marine sources, rapeseed, cottonseed, and sunflower. It has low solubility in water, but is an excellent emulsifier . In aqueous solution, its phospholipids can form either liposomes , bilayer sheets, micelles , or lamellar structures, depending on hydration and temperature. This results in a type of surfactant that usually is classified as amphipathic . Lecithin is sold as a food supplement and for medical uses. In cooking, it is sometimes used as an emulsifier and to prevent sticking, for example in nonstick cooking spray .

 High-density lipoprotein (HDL) is one of the five major groups of lipoproteins , which, in order of sizes, largest to smallest, are chylomicrons , VLDL , IDL , LDL , and HDL, which enable lipids like cholesterol and triglycerides (fats), , to be transported within the water around cells, including the bloodstream.

 Even people with very low LDL levels are exposed to increased risk if their HDL levels are not high enough  HDL1, HDL2 & HDL3: HDL molecules are classified according to increasing density into 3 subclasses or fractions. P-171.

Risk Factors

 Only 1 in 500 people has the genetic form of hypercholesterolemia known as heterozygous familial type.

 Less than 1 in a million have the homozygous version.



Zygosity

is the degree of similarity of the alleles for a trait in an organism.

 Most eukaryotes have two matching sets of chromosomes ; that is, they are diploid . Diploid organisms have the same genes on each of their two sets of homologous chromosomes, except that the sequences of these genes may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a sex-determination system . If both alleles of a diploid organism are the same, the organism is homozygous the organism is heterozygous nullizygous .

for that trait. If one allele is missing, it is hemizygous for the trait. If they are different, , and, if both alleles are missing, it is  Thus, almost everyone has some control over whether blood cholesterol level is explained by endogenous production by the liver, dietary intake of cholesterol from meats, poultry, fish, seafood and dairy products explains most of the fluctuation in each person’s serum cholesterol level.

 Fruits veggies, nuts, grains and seeds have no cholesterol.

 The average goal should be less than 300mg per day. The average though is 450 mg for men and 320 mg among women.  Although a large egg has 200 mg, eggs also contain lecithin, which limits absorption of dietary cholesterol.

 P-172  Smoking, diabetes, obesity, ETOH, androgenic and anti-inflammatory steroids and emotional stress also negatively influence blood lipid levels, especially increasing triglyceride and LDL-C levels. Obesity and smoking reduce HDL-C. Total cholesterol, LDL-C and triglyceride levels are elevated in people with diabetes but levels tend to normalize when blood glucose levels are controlled.

 Androgenic: A steroid hormone, such as testosterone or androsterone, that controls the development and maintenance of masculine characteristics. Also called

androgenic hormone

.