Long-chain polyunsaturated fatty acids are an essential element in healthy nutrition. But first let's take a look at what polyunsaturated fatty acids really are.
Saturated Fatty Acids Versus Unsaturated Fatty Acids
"Saturation" is a chemical term. It describes whether the carbon atoms in a molecule of fat are all joined to the maximum number of hydrogen atoms, or whether some carbon atoms are "double bonded" and could accept hydrogen atoms in a chemical reaction.
A molecule of saturated fat does not have any room to accept any more hydrogen atoms. A molecule of unsaturated fat molecule can accept at least one more hydrogen atom. A molecule of polyunsaturated fat can accept multiple hydrogen atoms. What difference does this make?
- Saturated fats are hard at room temperature. Examples include the saturated fat in butter, cheese, lard, and suet.
- Monosaturated fats are liquid at room temperature but turn into solids in the refrigerator. Some unsaturated fats include avocado oil, olive oil, and coconut oil.
- Polyunsaturated fats are found in nuts, seeds, fish, leafy greens, and algae. These include the omega-6 and omega-3 essential fatty acids. Polyunsaturated fats may be cis- or trans- fats.
What Is the Difference Between Cis- and Trans- Polyunsaturated Fatty Acids?
The way to understand the relationship between fats and heart health is to begin with a picture of the heart cell as a body builder in a raincoat.
The heart is bathed in blood, and the contents of the cell would dissolve if it were not protected. Every cell in the heart (and the body as a whole) is lined with a protective coating of fat. Fat does not dissolve in the watery blood, so the cell can function intact.
Fats repel water, but they attract fats. The bloodstream “throws” fat at cells much as an archer might shoot an arrow.
A long, straight arrow enters the cell with easy, and causes minimal disruption to the flow of electrical charges across the surface of the cell.
A lumpy, short arrow, or, even worse, a lumpy long arrow, sticks in the cell’s protective coat and interrupts the flow of information across its surface.
Some dietary fats are long and straight, others are short and lumpy, and still others are combinations in between. The “lumpiness” of a fatty acid depends on the way its carbon atoms are arranged, that is whether the carbon “shaft” of the arrow is cis- or trans-.
On an atomic level, fatty acids are made of parallel chains of carbon. This means that cis- fatty acids have lines of carbon neatly aligned in parallel.
C - C - C - C - C - C
C - C - C - C - C - C
They slip neatly into the cell without disturbing the cell membrane, although a short arrow does not pick up the momentum it needs to enter the cell cleanly.
Trans- fatty acids contain carbons at various points in the chain that “elbow” other molecules in the lining of the cell out of the way.
C - C - C - C - C
C - C - C - C - C
A short, bent arrow might do minimal damage to the cell but a long, bent arrow is devastating.
Trans- fatty acids are made during the manufacturing of margarine, allowing to be stored and used in a solid form, during the process of frying vegetable oils, and by bacterial action in the stomachs of cows, sheep, and goats.
Beef, lamb, and chevron (goat meat) contain much smaller quantities of trans- fatty acids than margarine or fried foods.
Fatty acids of all kinds are inherently beneficial to the heart.
They fuel the cells that pump blood.
They form the lining that conducts electrical impulses and protects the cells. But fatty cells that do not reach their destination, that get stuck in the membrane outside the cell, cause heart damage.
The Bottom Line About Polyunsaturated Fatty Acids
It's important to avoid trans- fats. But it is at least as important to make sure you get enough omega-3 fats.
Regular supplementation with fish oil or microalgae will help your body deal with all the other kinds of fats you consume in foods, and protect your heart from some of the cumulative effects of past nutritional mistakes.
- Diniz YS, Cicogna AC, Padovani CR, Santana LS, Faine LA, Novelli EL (2004). "Diets rich in saturated and polyunsaturated fatty acids: metabolic shifting and cardiac health". Nutrition 20 (2): 230-4.