INTRODUCTION TO CHOLESTEROL

Cholesterol, from the Ancient Greek chole- (bile) and stereos (solid) followed by the chemical suffix -ol for an alcohol , is an organic molecule. It is a sterol (or modified steroid ), a lipid molecule and is
biosynthesized by all animal cells because it is an essential structural component of all animal (not plant or bacterial) cell membranes that is required to maintain both membrane structural integrity and fluidity.

Cholesterol enables animal cells to dispense with a cell wall to protect membrane integrity and cell viability, thus allowing them to change shape and move about (unlike bacteria and plant cells which are restricted by their cell walls).

In addition to its importance within cells, cholesterol also serves as a precursor for the biosynthesis of steroid hormones and bile acids. Cholesterol is the principal sterol synthesized by animals. All kinds of cells in animals can produce it. In vertebrates the
hepatic cells typically produce greater amounts than other cells. It is almost completely absent among prokaryotes (bacteria and archaea), although there are some exceptions such as Mycoplasma, which require cholesterol for growth.

François Poulletier de la Salle first identified cholesterol in solid form in gallstones in 1769.

However, it was not until 1815 that chemist Michel Eugène Chevreul named the compound "cholesterine".

WHAT IS IT?

To understand high blood cholesterol (ko-LES-ter-ol), it helps to learn about cholesterol. Cholesterol is a waxy, fat-like substance that’s found in all cells of the body.

Your body needs some cholesterol to make hormones, vitamin D, and substances that help you digest foods. Your body makes all the cholesterol it needs. However, cholesterol also is found in some of the foods you eat.

Cholesterol travels through your bloodstream in small packages called lipoproteins (lip-o-PRO-teens). These packages are made of fat (lipid) on the inside and proteins on the outside.

Two kinds of lipoproteins carry cholesterol throughout your body:
▶low-density lipoproteins (LDL) 
▶high-density lipoproteins (HDL)

Having healthy levels of both types of lipoproteins is important.

LDL cholesterol sometimes is called “bad” cholesterol. A high LDL level leads to a buildup of cholesterol in your arteries. (Arteries are blood vessels that carry blood from your heart to your body.)

HDL cholesterol sometimes is called “good” cholesterol. This is because it carries cholesterol from other parts of your body back to your liver. Your liver removes the cholesterol from your body.

WHERE DOES CHOLESTROL COMES FROM?

The liver is responsible for managing the levels of LDL in the body. It manufactures and secretes LDL into the bloodstream. There are receptors on liver cells that can "monitor" and try to adjust the LDL levels. However, if there are fewer liver cells or if they do not function effectively, the LDL level may rise.

Diet and genetics both play a factor in a person's cholesterol levels. There may be a genetic predisposition for familial hypercholesterolemia (hyper=more = cholesterol + emia=blood) where the number of liver receptor cells is low and LDL levels rise causing the potential for atherosclerotic heart disease at a younger age.

In the diet, cholesterol comes from saturated fats that are found in meats, eggs, and dairy products. Excess intake can cause LDL levels in the blood to rise. Some vegetable oils made from coconut, palm, and cocoa are also high in saturated fats.

WHAT IS ITS FUNCTIONS?

Cholesterol has four main functions, without which we could not live.
It:
▶Contributes to the structure of cell walls
▶Makes up digestive bile acids in the intestine
▶Allows the body to produce vitamin D
▶Enables the body to make certain hormones

WHAT IS HIGH BLOOD CHOLESTEROL?

High blood cholesterol is a condition in which you have too much cholesterol in your blood. By itself, the condition usually has no signs or symptoms. Thus, many people don’t know that their cholesterol levels are too high.

People who have high blood cholesterol have a greater chance of getting coronary heart disease, also called coronary artery disease. (In this article, the term “heart disease” refers to coronary heart disease.)

The higher the level of LDL cholesterol in your blood, the GREATER your chance is of getting heart disease. The higher the level of HDL cholesterol in your blood, the LOWER your chance is of getting heart disease.

Coronary heart disease is a condition in which plaque (plak) builds up inside the coronary (heart) arteries. Plaque is made up of cholesterol, fat, calcium, and other substances found in the blood. When plaque builds up in the arteries, the condition is called atherosclerosis (ATH-er-o-skler-O-sis).

Over time, plaque hardens and narrows your coronary arteries. This limits the flow of oxygen-rich blood to the heart.
Eventually, an area of plaque can rupture (break open). This causes a blood clot to form on the surface of the plaque. If the clot becomes large enough, it can mostly or completely block blood flow through a coronary artery.

If the flow of oxygen-rich blood to your heart muscle is reduced or blocked, angina (an-JI-nuh or AN-juh-nuh) or a heart attack may occur.

Angina is chest pain or discomfort. It may feel like pressure or squeezing in your chest. The pain also may occur in your shoulders, arms, neck, jaw, or back. Angina pain may even feel like indigestion.

A heart attack occurs if the flow of oxygen-rich blood to a section of heart muscle is cut off. If blood flow isn’t restored quickly, the section of heart muscle begins to die. Without quick treatment, a heart attack can lead to serious problems or death.

Plaque also can build up in other arteries in your body, such as the arteries that bring oxygen-rich blood to your brain and limbs. This can lead to problems such as carotid artery disease , stroke, and peripheral artery disease.

WHAT ARE ITS SYMPTOMS?

Having high cholesterol levels, while a risk factor for other conditions, does not itself present any signs or symptoms. Unless routinely screened through regular blood testing, high cholesterol levels will go unnoticed and could present a silent threat of heart attack or stroke.

 
WHAT CAUSES IT?

Many factors can increase your chances of having heart problems or a stroke if you have high cholesterol.

These include:
▶an unhealthy diet – in particular, eating high levels of saturated fat
▶smoking – a chemical found in cigarettes called acrolein stops HDL transporting cholesterol from fatty deposits to the liver, leading to narrowing of the arteries (atherosclerosis)
▶having diabetes or high blood pressure (hypertension)
▶having a family history of stroke or heart disease

There's also an inherited condition called familial hypercholesterolaemia, which can cause high cholesterol even in someone who eats healthily.

HOW CAN IT BE DIAGNOSED?

High cholesterol can only be diagnosed by blood testing. Doctors' guidelines state that everyone over the age of 20 years should have their cholesterol levels checked once every five years.

The cholesterol test is done after a period of fasting - no food, drink or pills for 9 to 12 hours - to enable an accurate reading of LDL cholesterol from the blood test. The screening also gives information about total cholesterol, HDL cholesterol and triglyceride levels.

The guidelines set cholesterol levels that help determine the individual heart risk, as follows:

▶LDL cholesterol

Optimal: less than 100 mg/dL
Near-optimal: 100 to 129 mg/dL
Borderline high: 130 to 159 mg/dL
High: 160 to 189 mg/dL
Very high: 190 mg/dL and above

Guidance is also set out for the other measures in the lipid profile:

▶Total cholesterol

Desirable: less than 200 mg/dL
Borderline high: between 200-239 mg/dL
High: 240 mg/dL or above.
HDL cholesterol
Low: below 40 mg/dL
High: 60 mg/dL or above

After more than a decade of recommendations that physicians treat patients in an attempt to lower cholesterol to less than 100mg/dL or less than 70mg/dL, new guidelines from the American College of Cardiology (ACC) and American Heart Association (AHA), developed with the National Heart, Lung, and Blood Institute (NHLBI) abandon this idea of LDL- and non-HDL-cholesterol targets.

There is no evidence from randomized, controlled clinical trials to support treatment to a specific target. So, instead of physicians prescribing numerous medications simply for the sake of reducing cholesterol levels, even when patients have no other risk factors for heart disease, the new guidelines recommend that physicians identify four groups of patients who are likely to benefit from statin treatment to better prevent primary and secondary cardiovascular events:

▶People with clinical atherosclerotic cardiovascular disease
▶People who have LDL-cholesterol levels over 190 mg/dL, such as those with familial hypercholesterolemia
▶People aged 40 to 75 years old with
diabetes and LDL-cholesterol levels of 70-189 mg/dL and with no evidence of atherosclerotic cardiovascular disease
▶People without evidence of cardiovascular disease or diabetes but who have LDL-cholesterol levels of 70-189 mg/dL and a 10-year risk of atherosclerotic cardiovascular disease greater than 7.5%.

WHAT MEDICATIONS ARE AVAILABLE TO TREAT HBC?

There are four classes of medication that can lower cholesterol levels including statins, niacin, bile acid resins, and fibric acid derivatives.

▶A variety of statin drugs are on the market including simvastatin ( Zocor ), atorvastatin (Lipitor ), pravastatin (Pravachol), fluvastatin (Lescol ), lovastatin (Mevacor ), and
rosuvastatin (Crestor). These drugs primarily decrease LDL.
▶Cholestyramine (Questran ) is a bile acid resin and decreases LDL.
▶Fibric acid resins lower LDL and include
gemfibrozil (Lopid) and fenofibrate ( Tricor).
▶Niaspan is the prescription form of niacin and decreases LDL and triglycerides as well as increases HDL.
▶Alirocumab (Praluent) and evolocumab (Repatha) are two new medications that are antibodies to a protein, PCSK9. These drugs are indicated in patients who have had heart attack or stroke or have familial hypercholesterolemia and are taking maximum therapy and continue to have high LDL cholesterol levels in their blood.

The choice as to what medication is most appropriate is usually individualized by the health care professional in discussion with the patient. These medications often need to be adjusted and monitored for side effects.

While all four medication groups may have a role in controlling cholesterol levels in association with diet, exercise, and smoking cessation, only statins are shown to decrease the risk of heart attack.

The American Heart Association and the American College of Cardiology recommend that statin therapy may benefit patients with a history of heart attack, those with elevated blood LDL cholesterol levels or type two
diabetes, and a those with a 10-year risk of heart disease greater than 7.5%.

Calculate your risk online with the American Heart Association's CV Risk Calculator.

When monitoring how well statin therapy works, the goal is no longer to reach a specific blood cholesterol level. Instead patients with a high risk of heart disease will aim to decrease their cholesterol levels by 50% and those with a lesser risk will aim to lower their cholesterol levels by 30% to 50%.

HBC LINKED TO INFERTILITY?

Prospective parents with high cholesterol levels could be in for a long wait to become pregnant, a new study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism states.

The cohort study, "Lipid Concentrations and Couple Fecundity: The LIFE Study," comprises 501 couples, 18 to 40 years old, from 16 counties across Michigan and Texas recruited prior to conception in 2005-2009.

These couples were part of the Longitudinal Investigation of Fertility and the Environment (LIFE) study, which aimed to ascertain whether ever-present environmental chemicals in the context of lifestyle affect male and female fertility. Participants had discontinued use of any contraceptives - with the aim of getting pregnant - and were tracked daily for 12 months while attempting to conceive. Parents-to-be were followed monthly until delivery.

Among the 401 (80%) women who completed the protocol, 347 (87%) became pregnant and 54 (13%) did not. Over the course of the study, 100 (20%) withdrew, most commonly due to a lack of continued interest in participation.

Results indicate that those couples in which either one or both had high cholesterol took considerably longer to become pregnant than those couples with cholesterol within the normal scale.

"Couples in which both the prospective mother and father had high cholesterol levels took the longest time to conceive a child," says Schisterman.
"Our study also found couples in which the woman had high cholesterol and the man did not took longer to become pregnant than couples where both partners had cholesterol levels in the normal range," he adds.

FIVE SECRET TO LOWER IT!

Here are five things you can do to eat better, feel better… and lower your cholesterol.

▶1. Eat more vegetables and fruit
Fill half your plate with vegetables and fruit at mealtime. Choose brightly coloured vegetables and fruit more often. Use fresh, frozen or canned vegetables and fruit.

▶2. Add meat alternatives to your meals
Fill one quarter of your plate with meat alternatives such as beans or lentils more often. Top your salad or stir fry with nuts or seeds. Add canned legumes to foods you already enjoy such as chili or spaghetti sauce.
▶3. Boost your soluble fibre
Choose whole grain products more often. Include oats, barley, psyllium, beans, chickpeas and lentils often. Eat more vegetables and fruit.
▶4. Choose healthy fats
Aim for 2-3 tablespoons of added unsaturated fat per day. Choose oil, non-hydrogenated margarine, mayonnaise and salad dressing. Limit saturated and trans fats such as butter, lard, coconut oil, hard margarine and shortening. Eat at least two servings of fish per week. Try fatty fish like salmon, mackerel, arctic char, sardines, herring and trout.

▶5. Consider including plant sterols
Talk to your Sobeys Dietitian or Sobeys Pharmacist about whether plant sterols are right for you. Look for products fortified with plant sterols, such as some brands of margarine or juice.

WHAT ARE SOME CHOLESTEROL LOWERING FOODS?

Do you want a diet to lower cholesterol? We all know that butter, ice cream, and fatty meats raise cholesterol , but do you know which foods make up a low- cholesterol diet? Find out here.

Here's some good news. To lower your
cholesterol , you can actually eat more of certain foods. A handful of some "functional foods" have been shown to make a big impact on your cholesterol levels . They're also much tastier than a pill chased with a glass of water.

Researchers have found that some foods -- such as fatty fish, walnuts, oatmeal, and oat bran, and foods fortified with plant sterols or stanols -- can help control your cholesterol. Some studies have shown that a diet combining these "superfoods" may work as well as some cholesterol-lowering medicines to reduce your "bad" LDLcholesterol levels.

WHAT OTHER LIFESTYLE INTERVENTIONS HELP LOWER IT?

Weight loss and exercise are shown to decrease total cholesterol while increasing levels of HDL, the good cholesterol.

Smoking cessation decreases LDL levels plus smoking is a primary risk factor for heart disease and stroke. One drink of alcohol a day may help increase HDL levels, but too much alcohol can damage the liver and increase the risk of elevated LDL.