Live for lipids 

By Daniel Rocha 

Lipids include triglycerides, phospholipids, and sterols such as cholesterol. Lipids dissolve in solvents like alcohol and acetone, but they are not soluble in water.  The body uses fats and other lipids to provide and store energy, form and maintain cell membrane, production of hormones, insulation for the body, cushion for the body, and aids in absorbing fat-soluble vitamins.  The human body requires a certain amount of lipids. 

Fatty acids can be broken down into saturated and unsaturated fatty acids.  Unsaturated fatty acids can be broken down into mono and polyunsaturated fatty acids.  Omega 3 and 6 fatty acids can not be produced by the body and therefore must be supplied by one's diet.  Trans fatty acid molecules that are found in foods result from the hydrogenation process.  

Cholesterol is a component of cell membranes and participates in hormones like estrogen and testosterone. Cholesterol includes low-density lipoproteins (LDL), bad cholesterol, and high-density lipoproteins (HDL), or good cholesterol. LDL is  “bad” because it accumulates on the walls of arteries and blocks blood flow. HDL is “good” because it removes LDL, keeping it from building up in the arteries.

Triglycerides contain a mixture of unsaturated and saturated fatty acids. Triglycerides include three fatty acids attached to a glycerol backbone.  Triglycerides travel through the circulatory system, where they are either utilized immediately or are stored in adipose tissue. Triglycerides can serve as a storage medium because of their hydrophobicity, allowing them to be stored as droplets without contact with water molecules. The body may contain several months of fuel stored in the form of triglycerides. Physiological conditions dictate the need to use the triglycerides. Hormones or a neurotransmitter signal their release in response to exercise, stress, or fasting. Lipase breaks down the triglyceride molecule into a glycerol molecule and three fatty acids. These breakdown products are transported within the circulatory system to the tissues that need energy.

Phospholipds have both hydrophilic and hydrophobic regions which make them partially soluble in water and can serve as an emulsifier. Phospholipids are a structural component for cell membranes and nerve cells. Cholesterol is used by cells to make bile and vitamin D, and found only in animal foods.  

Triglycerides and phospholipids digest primarily in the duodenum. Bile emulsifiers, fat molecules, and pancreatic lipase remove two fatty acids from triglycerides.  Cholesterol is packaged in micelles along with monoglycerides, fatty acids, and phospholipids.  Chylomicrons form within the small intestine and are coated with protein and enter the lymphatic system and then the bloodstream.  The liver uses lipids from chylomicrons to make other lipoproteins. 

Dietary cholesterol is found in animal food sources such as meat, poultry, seafood, and dairy products. Cholesterol does not dissolve in the blood. Instead, it is transported to and from the cells by lipoproteins present in blood plasma. Some lipid disorders are inherited, but poor dietary habits such as high fat and high sugar diets can lead to high LDL and high triglycerides. 

“Other risk factors for lipid disorders include:

A lack of regular physical activity, smoking, which lowers HDL (good) cholesterol in the blood, alcohol intake, which can raise HDL (good) cholesterol when used in moderation but can also increase triglyceride levels too much, being overweight and obesity, which can cause high cholesterol levels, certain other medical disorders, such as diabetes, liver disease, and kidney disease, and lastly the use of certain medications, such as some steroids, birth-control pills, and blood-pressure drugs” (Mertz 2018) 

Blood lipid testing checks a patient's lipid values and assesses the risks associated with abnormally high or low lipid concentrations. Low levels of cholesterol indicate liver failure and inherited disorders of cholesterol production. Elevated blood cholesterol results in coronary artery disease (CAD). Low levels of triglyceride are a result of malnutrition or malabsorption. High levels reflect diabetes mellitus, hypothyroidism, pancreatitis, glycogen storage diseases, and estrogens.

Hyperlipidemia is a high level of lipids (fats) in the bloodstream. These lipids include cholesterol, cholesterol compounds, phospholipids, and triglycerides, all carried in the blood by lipoproteins.

A nutritionist or registered dietician may advise a patient with hyperlipidemia with dietary guidelines, including reducing saturated fat intake to 7% of the daily intake of calories. Reduce total fat intake to 25%–35% of the daily intake of calories, with 20–30 g a day of soluble fiber, and 2–3 g daily of plant sterols. Simply using a diet low in total fat, saturated fat, and cholesterol is recommended, along with avoiding alcohol intake and losing weight. (Laberge 2019)


Fallon, F. L., Jr. (2020). Lipid Panel. In J. L. Longe (Ed.), The Gale Encyclopedia of Medicine (6th ed., Vol. 5, pp. 3057-3058). Gale.

Laberge, M., PhD, & Blackwell, A. H., PhD. (2019). Hyperlipidemia. In D. S. Hiam (Ed.), The Gale Encyclopedia of Diets (3rd ed., Vol. 1, pp. 711-716). Gale.

Mertz, L. A., PhD. (2018). Lipid Disorders. In J. L. Longe (Ed.), The Gale Encyclopedia of Nursing and Allied Health (4th ed., Vol. 4, pp. 2070-2074). Gale.

Sims, J. L. (2019). Triglycerides. In D. S. Hiam (Ed.), The Gale Encyclopedia of Diets (3rd ed., Vol. 2, pp. 1245-1249). Gale.

Stephenson, T. J., Ph.D., & Schiff, W. J., RDN. (2018). HUMAN NUTRITION: Science for healthy living. NY, NY: MCGRAW-HILL EDUCATION