Notes on Fats and Cholesterol

Overview of Fats and Cholesterol

  • Lipids: Fats and cholesterol are categorized as lipids, a class of nutrients essential for various bodily functions.

Types of Fatty Acids

  • Long-chain fatty acids: 14 to 24 carbon atoms

  • Medium-chain fatty acids: 6 to 12 carbon atoms

  • Short-chain fatty acids: 2 to 4 carbon atoms

  • Saturated Fatty Acids:

    • Composed entirely of carbon-carbon single bonds.

    • No double bonds present.

  • Unsaturated Fatty Acids:

    • Includes Omega 3 fatty acids which are known for their health benefits.

    • Characterized by one or more carbon-carbon double bonds.

Essential Fatty Acids

  • Must be obtained from the diet:

    • Alpha-linolenic acid (Omega-3)

    • Linoleic acid (Omega-6)

Caloric Content

  • Fats provide 9 calories per gram; carbohydrates provide 4 calories per gram.

Cholesterol and Cardiovascular Health

  • Normal Cholesterol Levels: A blood cholesterol level of 200 does not necessarily indicate a risk for atherosclerosis (false assumption).

  • In the U.S., heart disease and strokes accounted for about 20% of deaths as of 2020.

  • Atherosclerosis: A chronic condition leading to plaque buildup in arterial walls, which may lead to cardiovascular diseases.

  • Excess abdominal fat correlates with elevated levels of LDL cholesterol and triglycerides.

Nutrition Facts Panel

  • Important to check for:

    • Total fat

    • Saturated fat

    • Trans fat

    • Cholesterol

Hormones & Digestion

  • Cholecystokinin: A hormone that stimulates the gallbladder to release bile and prompts the pancreas to secrete digestive enzymes.

Lipoproteins

  • Transport lipids from the intestines and liver to body tissues.

  • Lipoproteins are water soluble structures that transport lipids through the bloodstream

  • Major classes include:

    • Chylomicrons

    • Very low density lipoproteins (VLDL)

    • Low density lipoproteins (LDL)

    • High density lipoproteins (HDL)

Properties of Trans Fats

  • Trans fatty acids have a similar structure to saturated fatty acids.

  • They do not provide the same benefits as medium-chain saturated fatty acids.

Triglycerides and Phospholipids

  • Triglycerides: Composed of three fatty acids attached to a glycerol backbone.

  • Phospholipids: Contain both hydrophilic (water-attracting) and hydrophobic (water-repelling) portions.

Chemical Structure of Fatty Acids

  • Cis fatty acids (e.g., oleic acid) have a kink or bend where double bonds are present in the carbon chain.

  • Trans fatty acids (e.g., elaidic acid) feature hydrogen atoms on opposite sides of the double-bonded carbon, resembling saturated fats chemically.

Source of Cholesterol

  • Cholesterol is found only in animal products such as:

    • Chicken

    • Ice cream

    • Eggs

Characteristics of Saturated Fats

  • Saturated fatty acids: Recognized by the absence of carbon-carbon double bonds.

Compounds that can be saturated of unsaturated are fatty acids

What is the chemical structure of an Omega 3 fatty acid. The 1st carbon carbon double bound on the thirds carbon from the omega end of the carbon chain

What is the back bone of a triglyceride is glycerol

The long term process in which plaque builds up inside arterial walls is atherosclerosis

What transports lipids from the small intestine and liver to body tissue? Lipoproteins