Applied Microbiology Lecture 4: Cholesterol and PUFAs

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Questions and Answers

What is the primary function of HDL in the human body?

To carry cholesterol from other parts of the human body back to the liver, where it is removed from the body.

What is the difference between LDL and VLDL?

LDL mainly carries cholesterol, while VLDL mainly carries triglycerides.

What is the primary source of cholesterol in the human diet?

Foods from animal sources, such as egg yolks, meat, and cheese.

What is the result of high cholesterol in the bloodstream?

The buildup of plaque in the arteries, leading to atherosclerosis and potentially coronary artery disease. Signup and view all the answers

What is the role of protein in lipoproteins?

To allow lipids to move through the blood by attaching to them. Signup and view all the answers

What are the two types of unhealthy fats that can contribute to high cholesterol?

Saturated fats and trans fats. Signup and view all the answers

What is the function of cholesterol in the human body?

To make hormones, vitamin D, and substances that help digest foods. Signup and view all the answers

What is the effect of high LDL levels in the bloodstream?

The buildup of plaque in the arteries, leading to atherosclerosis and potentially coronary artery disease. Signup and view all the answers

What is one habit that can lower HDL cholesterol?

Lack of physical activity Signup and view all the answers

What is a genetic condition that can cause high cholesterol?

Familial hypercholesterolemia (FH) Signup and view all the answers

What can happen if a blood clot forms on the surface of a plaque in a coronary artery?

It can block blood flow to the heart muscle, causing angina or a heart attack Signup and view all the answers

What is one other area of the body where plaque can build up and cause problems?

Arteries that bring oxygen-rich blood to the brain and limbs Signup and view all the answers

What did researchers find about the effect of reducing saturated fats on cholesterol levels?

It may not help curb the risk of heart disease or add years to your life Signup and view all the answers

What is one type of oil that food manufacturers are being ordered to stop using?

Partially hydrogenated oils (PHOs) or trans fats Signup and view all the answers

What is one diet recommendation that is not in doubt, according to Dr. Lennert Veerman?

Eating a varied diet rich in whole fruits, vegetables, and whole grains Signup and view all the answers

What is one risk factor for high cholesterol that is especially important for women to consider?

Smoking Signup and view all the answers

What is the FDA's stance on partially hydrogenated oils (PHOs)?

The FDA argues that PHOs are no longer 'generally recognized as safe'. Signup and view all the answers

What health issues have been linked to trans fats?

Cancer, obesity, metabolism issues, heart disease, and Alzheimer's. Signup and view all the answers

What are polyunsaturated fatty acids (PUFAs) and why are they essential?

PUFAs are long-chain fatty acids with 18 or more carbon atoms containing two or more double bonds. They are essential because they cannot be made by the body and must be supplied by the diet or supplements. Signup and view all the answers

What is the recommended omega-6 to omega-3 PUFA ratio?

The British Nutrition Foundation recommends an omega-6 to omega-3 PUFA ratio of 3:1. Signup and view all the answers

What are the benefits of PUFAs in the body?

Regulating membrane architecture, controlling gene expression, affecting cholesterol transport, preventing heart disease, and playing a role in brain functions, growth, and development. Signup and view all the answers

What is the minimum recommended intake of PUFAs as a percentage of total lipid intake?

At least 3% of the total lipid intake. Signup and view all the answers

What is the most common source of omega 6s?

Linoleic acid, found in corn oil, soybean oil, safflower oil, cottonseed oil, sunflower oil, poultry, and some nuts and seeds. Signup and view all the answers

What is the role of omega-6 fatty acids in the body?

Omega-6 fatty acids are necessary for survival, but they also cause inflammation and compete with omega-3s in the body. Signup and view all the answers

What are the limitations of using fish oil as a source of PUFAs?

Fish oil is an unsustainable source, has a climate- and geographical area-dependent composition, is high in cholesterol, and may contain heavy metals, have a complex mixture of fatty acids, and is expensive to purify, with a fishy smell and taste. Signup and view all the answers

What is the main commercial source of PUFAs?

Fish oil Signup and view all the answers

What is the typical omega-6 to omega-3 ratio in the average American diet?

Anywhere from 12:1 to 25:1. Signup and view all the answers

What is EPA used for in combination with DHA in fish oil preparations?

Preventing and reversing heart disease, decreasing irregular heartbeats, asthma, and cancer. Signup and view all the answers

What is the advantage of microbial PUFAs over fish oil?

Oil production can be carried out throughout the year, is easy to manipulate, and can be grown on waste products, lacks unpleasant smell, and usually produces only one type of PUFAs. Signup and view all the answers

What is the chemical structure of Eicosapentaenoic acid (EPA)?

C20:5(n-3) Signup and view all the answers

Which microalgae is used to produce EPA?

Nannochloropsis Signup and view all the answers

What is the benefit of using microalgae for PUFA production?

Easy to manipulate for maximizing productivity, can grow on waste products, and lacks unpleasant smell. Signup and view all the answers

Study Notes

Cholesterol and Lipoproteins

Cholesterol is a waxy, fat-like substance found in all human cells, essential for making hormones, vitamin D, and substances that help digest foods.
High levels of cholesterol in the blood can combine with other substances to form plaque, leading to atherosclerosis and coronary artery disease.
HDL (high-density lipoprotein) is considered "good" lipid because it carries cholesterol from other parts of the body back to the liver for removal.
LDL (low-density lipoprotein) is considered "bad" lipid because high levels can lead to the buildup of plaque in arteries.
VLDL (very low-density lipoprotein) also contributes to the buildup of plaque in arteries, mainly carrying triglycerides.

Causes and Health Problems of High Cholesterol

Unhealthy eating habits, such as consuming saturated and trans fats, can raise LDL levels.
Lack of physical activity and smoking can lower HDL levels.
Genetics, certain medical conditions, and medications can also cause high cholesterol.
High cholesterol can lead to plaque buildup in arteries, increasing the risk of angina, heart attack, carotid artery disease, stroke, and peripheral arterial disease.

Polyunsaturated Fatty Acids (PUFAs)

PUFAs are long-chain fatty acids with 18 or more carbon atoms, containing two or more double bonds, essential for human health.
They must be supplied by the diet or supplements, as the body cannot produce them.
Examples of PUFAs include omega-3 fatty acids found in fish oil, such as DHA and EPA.
PUFAs have various benefits, including regulating membrane architecture, controlling gene expression, affecting cholesterol transport, preventing heart disease, and playing a role in brain function and development.

Benefits and Sources of PUFAs

PUFAs can inhibit tumor cell growth and are important for the formation of the outer retina of the eyes.
The recommended daily intake of PUFAs is at least 3% of total lipid intake.
The ideal omega-6 to omega-3 ratio is 4:1, but the average Western diet has a ratio of 12:1 to 25:1.
Fish oil is a common source of PUFAs, but it has limitations, such as being an unsustainable source, containing high cholesterol, and requiring expensive purification.
Alternative sources include marine microorganisms, which can be grown on waste products and produce only one type of PUFAs.

Applications of PUFAs

EPA is used to treat various conditions, including high blood pressure in high-risk pregnancies, age-related macular degeneration, heart disease, schizophrenia, and depression.
EPA is also used in combination with DHA in fish oil preparations and with RNA and L-arginine to reduce infections and improve wound healing.

Microbial PUFAs

Microbial PUFAs can be produced throughout the year, regardless of season or climate.
Production conditions can be easily manipulated to maximize productivity.
Microorganisms can grow on waste products, reducing production costs, and lack unpleasant smells.
Microbial PUFAs are typically of a single type, making them more desirable.

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Description

This lecture covers the basics of cholesterol, HDL, LDL, and VLDL, as well as the biosynthesis, sources, and applications of PUFAs in microbial cells. Learn about the composition of a microbial cell and the importance of PUFAs.