Good fats, bad fats, trans fats, omega-3, omega-6, hydrogenated, unsaturated… it gets confusing trying to sort out just which fats we are supposed to eat and which ones to avoid like the plague. Bear with me – with a little explanation and a little chemistry you will understand the language on fats – and more importantly know how and why to include the healthy ones in your diet.
Healthy fats are a necessary part of the human diet and help make up nerve and brain tissue, cell membranes, and beneficial steroid hormones such as estrogen, testosterone, and vitamin D. Fats are necessary for us to absorb fat soluble vitamins (K, A, D, E) and they can fight inflammation. However, the wrong fats are linked to many diseases including heart disease, cancer, and inflammatory and autoimmune diseases.
Fats in the diet are primarily fatty acids (FAs) consisting of the elements carbon (C), hydrogen (H) and oxygen (O). The C chain acts as a skeleton with H attached all along the chain and at one end of the chain is a chemical group called carboxyl (-COOH). The C atoms are bound together by a single or double bond depending on whether 2H or 1H atoms are attached. When a C atom has only one H attached it has room for another, and the bond to its neighboring C is double. With 2Hs attached the C atom is full and attaches to its neighbor by a single bond. This determines the basis for “saturated” or “unsaturated” fatty acids and also “trans” vs “cis” fatty acids.
Saturated fatty acids (SFAs) have all the H that the C atoms can hold, the FA is “saturated” with H atoms, and there are no double bonds in the C chain. Monounsaturated fatty acids (MUFAs) have only one C atom with a single H attached and only one double bond in the C chain. Polyunsatuated fatty acids (PUFAs) have more than one double bond. As you will read later the double bonds and where they are located along the C chain determines most of the health properties, good or bad, of FAs.
What are Omega-3 and Omega-6 Fatty Acids?
FAs have common and scientific names. The scientific name is based on Greek and refers to how many C atoms long the chain is, how many double bonds are present, and where they are located. The C atoms are labeled in Greek also, as alpha, beta, gamma, and so on to the end which is always “omega”, being the last letter in the Greek alphabet. The alpha carbon is always at the carboxyl end of the FA and the location of a double bond from the omega end of the FA determines the familiar omega designation.
Omega-3 and omega-6 FAs are “essential fatty acids” (EFAs) that must be included in the diet because humans cannot make them from other FAs. Those with a double bond that is three C atoms from the omega end is called “omega-3”; with a double bond 6 that is six C atoms from the omega end it is called “omega-6”, and so on.
For example, borage oil is a good source for Gamma-Linoleic Acid (GLA) which contains eighteen C atoms and three double bonds located six, nine and twelve C atoms from the omega end of C chain. GLA’s scientific name is 6,9,12-octadeca-trienoic acid. Octadeca means eighteen, and tri-enoic means three double bonds. Since the twelve position double bond is six C atoms from the omega end, this makes GLA an omega-6 FA. Since is has multiple double bonds, GLA is a PUFA.
The omega-6 FAs lead to inflammation, breaking down first to Arachidonic Acid (AA) then onto the inflammation producing prostaglandins, leukotrienes and others. Drugs such as Ibuprofen and Celebrex inhibit the enzymes that break down AA. So do curcumin and other herbs, with less side effects. The omega-3 FAs will inhibit the breakdown of AA and thus lower inflammation. Sugar, high-glycemic foods, and insulin will encourage AA breakdown leading to inflammation.
Nature intended for humans to get about a 2:1 ratio of omega-6:omega-3 FAs, yet in America we are getting a 20:1 ratio of these FAs in our diet. This results from eating too much animal fat (red meat), fried food, and packaged or processed foods.
What about Trans-Fats and Hydrogenated Oils?
The Latin prefixes “cis” and “trans” describe the orientation of the H atoms on either side of a double bond between C atoms. Cis means “on the same side” and trans means “on the other side”. Naturally occurring FAs generally have the cis configuration which causes the FA to bend at that bond making a “V” shape. The trans configurations look more like a straight line. Trans-fats are not natural yet when consumed they are incorporated into cell membranes and alter the normal functions of the cell. They raise cholesterol and increase the risk of heart disease. They also have a detrimental effect on the brain and nervous tissue, altering nerve cell communications and causing nerve degeneration.
Hydrogenated oils have more H atoms forced into the FA in order to reduce or eliminate the number of double bonds in the FA. Unsaturated fats are more prone to oxidation and going rancid so hydrogenation increases the shelf life. Fully hydrogenated oils are hard and waxy so manufacturers stop the process at the desired oil texture, leaving “partially hydrogenated” oils. The high temperatures and catalysts used in this process eliminate a large number of the C double bonds leaving more of the unhealthy trans-fats.
How About Triglycerides?
Triglycerides (TG) are the main form of fat in vegetable oils and animal fats. A TG is a chemical compound formed from one molecule of glycerol and three FAs thus the name tri-glyceride. Oils have varying amounts of different FAs attached to glycerol and as such are made up of different proportions of saturated and unsaturated FAs.
Artificial fats such as Olestra are created from sucrose instead of glycerol, with up to eight FAs attached, which makes it too large to be metabolized. It passes through the body unchanged which causes less calories to be absorbed from the food, but it can cause side effects such as diarrhea or depletion of fat-soluble vitamins.
Scott Rollins, MD, is Board Certified with the American Board of Family Practice and the American Board of Anti-Aging and Regenerative Medicine. He specializes in bioidentical hormone replacement for men and women, thyroid and adrenal disorders, fibromyalgia and other complex medical conditions. He is founder and medical director of the Integrative Medicine Center of Western Colorado (www.imcwc.com) and Bellezza Laser Aesthetics (www.bellezzalaser.com). Call (970) 245-6911 for an appointment or more information.