The biology of fats in the body

April 29, 2013

When you have your cholesterol checked, the doctor typically gives you levels of three fats found in the blood: LDL, HDL and triglycerides. But did you know your body contains thousands of other types of fats, or lipids?

In alone, researchers have identified some 600 different types relevant to our health. Many lipids are associated with diseases—diabetes, stroke, cancer, arthritis, Alzheimer's disease, to name a few. But our bodies also need a certain amount of fat to function, and we can't make it from scratch.

Researchers funded by the National Institutes of Health are studying lipids to learn more about normal and abnormal biology. Chew on these findings the next time you ponder the fate of the fat in a French fry.

Fat functions

, cholesterol and other essential fatty acids—the scientific term for fats the body can't make on its own—store energy, insulate us and protect our . They act as messengers, helping proteins do their jobs. They also start involved in growth, , reproduction and other aspects of basic metabolism.

The cycle of making, breaking, storing and mobilizing fats is at the core of how humans and all animals regulate their energy. An imbalance in any step can result in disease, including heart disease and diabetes. For instance, having too many triglycerides in our bloodstream raises our risk of , which can lead to heart attack and stroke.

Fats help the body stockpile certain nutrients as well. The so-called "fat-soluble" vitamins—A, D, E and K—are stored in the liver and in fatty tissues.

Using a quantitative and systematic approach to study lipids, researchers have classified lipids into eight main categories. Cholesterol belongs to the "sterol" group, and triglycerides are "glycerolipids." Another category, "," includes the hundreds of lipids that constitute the and allow cells to send and receive signals.

Breaking it down

The main type of fat we consume, triglycerides are especially suited for energy storage because they pack more than twice as much energy as carbohydrates or proteins. Once triglycerides have been broken down during digestion, they are shipped out to cells through the bloodstream. Some of the fat gets used for energy right away. The rest is stored inside cells in blobs called droplets.

When we need extra energy—for instance, when we exercise—our bodies use enzymes called lipases to break down the stored triglycerides. The cell's power plants, mitochondria, can then create more of the body's main energy source: adenosine triphosphate, or ATP.

Recent research also has helped explain the workings of a lipid called an omega-3 fatty acid—the active ingredient in cod liver oil, which has been touted for decades as a treatment for eczema, arthritis and heart disease. Two types of these lipids blocked the activity of a protein called COX, which assists in converting an omega-6 fatty acid into pain-signaling prostaglandin molecules. These molecules are involved in inflammation, which is a common element of many diseases, so omega-3 fatty acids could have tremendous therapeutic potential.

This knowledge is just the tip of the fat-filled iceberg. We've already have learned a lot about lipids, but much more remains to be discovered.

Explore further: Gene mutation is linked to accumulation of fat, other lipids in liver

More information: Learn more about the science of health in the Inside Life Science series from NIH's National Institute of General Medical Sciences: publications.nigms.nih.gov/insidelifescience

Related Stories

Gene mutation is linked to accumulation of fat, other lipids in liver

January 31, 2012
A team of scientists from the University of Utah and the University of California at San Francisco has discovered that the mutation of a gene encoding a ketone body transporter triggers accumulation of fat and other lipids ...

Studying fish to learn about fat

June 28, 2012
In mammals, most lipids (such as fatty acids and cholesterol) are absorbed into the body via the small intestine. The complexity of the cells and fluids that inhabit this organ make it very difficult to study in a laboratory ...

Macrophage accumulation of triglycerides yields insights into atherosclerosis

October 1, 2012
A research report appearing in the Journal of Leukocyte Biology helps explain how specific immune cells, called macrophages, accumulate triglycerides to support their function. Because a characteristic finding in atherosclerosis ...

New link between high-fat 'Western' diet and atherosclerosis identified

October 9, 2012
Columbia University Medical Center (CUMC) researchers have found that a diet high in saturated fat raises levels of endothelial lipase (EL), an enzyme associated with the development of atherosclerosis, and, conversely, that ...

Recommended for you

Want to win at sports? Take a cue from these mighty mice

July 20, 2017
As student athletes hit training fields this summer to gain the competitive edge, a new study shows how the experiences of a tiny mouse can put them on the path to winning.

'Smart' robot technology could give stroke rehab a boost

July 19, 2017
Scientists say they have developed a "smart" robotic harness that might make it easier for people to learn to walk again after a stroke or spinal cord injury.

Engineered liver tissue expands after transplant

July 19, 2017
Many diseases, including cirrhosis and hepatitis, can lead to liver failure. More than 17,000 Americans suffering from these diseases are now waiting for liver transplants, but significantly fewer livers are available.

Lunatic Fringe gene plays key role in the renewable brain

July 19, 2017
The discovery that the brain can generate new cells - about 700 new neurons each day - has triggered investigations to uncover how this process is regulated. Researchers at Baylor College of Medicine and Jan and Dan Duncan ...

New animal models for hepatitis C could pave the way for a vaccine

July 19, 2017
They say that an ounce of prevention is worth a pound of cure. In the case of hepatitis C—a disease that affects nearly 71 million people worldwide, causing cirrhosis and liver cancer if left untreated—it might be worth ...

Omega-3 fatty acids fight inflammation via cannabinoids

July 18, 2017
Chemical compounds called cannabinoids are found in marijuana and also are produced naturally in the body from omega-3 fatty acids. A well-known cannabinoid in marijuana, tetrahydrocannabinol, is responsible for some of its ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.