Fats can be categorized in many ways: saturated, monounsaturated, polyunsaturated; according to their smoking points; liquid or solid; good for you (anti-inflammatory) or bad for you (pro-inflammatory), and essential and nonessential. Essential fats are those which you have to acquire through your diet; nonessential are those which your body can make on its own. All fatty acids consist of triglycerides composed of three fatty acid chains that are chemically bound to a glycerol molecule. Fatty acids are strings of carbon molecules with a variable number of double bonds between the carbon atoms and a methyl (-CH3) group at the end of the molecule.

This article will focus on the essential fats, of which there are two primary types:omega-6 fats and omega-3 fats. The omega number refers to where the first double bond occurs relative to the methyl end of the molecule, such that an omega-3 fat has a double bond between the 3rd and 4th carbon atoms from the methyl group. The fact that there is a double bond present is why the essential acids are described as unsaturated, as opposed to saturated fat like butter where there are no double bonds.

Omega-3 and omega-6 fats are polyunsaturated fats (PUFAs), containing more than one double bond in their carbon chain. Polyunsaturated fats tend to be liquid at room temperature as opposed to saturated fats which tend to be solid. When PUFAs are incorporated into cell membranes, they seem to lend more fluidity and flexibility to the cell membrane than when saturated fats are incorporated. This in turn affects how well the vast number of circulating hormones and chemicals can do their job.

There are only two fatty acids which are essential in humans: Linoleic acid (omega-6) and linolenic acid (omega-3). Linoleic acid can be elongated within the body to form arachidonic acid, and linolenic acid can be lengthened and desaturated to form eicosapentanoic acid. These are precursors for prostaglandins and leucotrienes which affect inflammation and immune function in our body. Drugs such as aspirin and non-steroidals as well as herbs such as ginger and boswellia work by affecting this conversion of arachidonic acids and eicosapentanoic acid into their subsequent forms as prostaglandins and leucotrienes.

Linoleic acid (omega 6) is found in grains, seeds, and oils, as well as in animals that eat those grains. Linolenic acid (omega3) is found in flaxseed, grasses, seaweed and algae. Walnuts are a readily available excellent source as well. One can bypass the conversion process of linolenic acid into eicosapentanoic acid by eating cold-water fish such as salmon and sardines, in which case you’d be taking in eicosapentanoic and docosahexanoic acid directly.

Both omega-3 and omega-6 are essential, but you don’t need to worry about ever having a deficiency of omega-6 fatty acids: we seem to be swimming in them and now have a plethora of chronic inflammatory diseases which we believe to be associated with the imbalance between omega-3 and omega-6. In prehistoric times, anthropologists believe that the ratio of omega-6 to omega-3 fats in the diet was 1:1. It is now a stunning 20 to 40 to 1. Nutrition experts are recommending that we try to reverse this ratio back to 4:1 in hopes of avoiding cardiovascular disease, osteoporosis, arthritis, some autoimmune disorders, and some mental illnesses.

As Michael Pollan points out in his book “The Omnivore’s Dilemma”, we are becoming corn – it is in almost everything which is processed. Governmental agricultural practices have sustained a cheap flood of corn, which is now used in finishing conventional beef. This is a relatively new process: this is the first century in which we are eating corn-finished beef. We have made several substantial changes in our diet in the last 75 years: we are consuming more dairy products (mostly from cows being fed corn or corn products), more meat, and much more sugar than ever before, as well as now including processed foods in our diet. As a result, we are overwhelming our bodies with pro-inflammatory omega-6 fatty acids.

Grass-fed beef, because they are not finished on corn full of omega-6 fatty acids, will be better for you than conventionally produced beef. Grass-fed beef actually contains omega-3 fats from the grass, though not in as much quantity as you would get in a cold-water fish. Not only are you improving your health by consuming grass-fed beef as opposed to conventional beef, but you are contributing to an environmentally sound farming practice.

Dr. Matthews is a gynecologic oncologist at Baylor University Medical Center, a clinical professor at Texas Tech and completing a fellowship in integrative medicine at the University of Arizona. Her fourth specialty is transportation, driving her two children to baseball, soccer, basketball, dance, piano and karate.