What are Healthy Fats?

First of all, fats are slightly different from the term you may have heard from various healthcare professionals—lipids. Fats are solid at room temperature, and lipids are liquid at room temperature. Another way to look at it is fats are large lipids that are made of fatty acids and glycerol. They are important in providing energy storage and insulation. In this article, since we are talking about healthy fats for humans, hopefully above room temperature (!), both terms will be used somewhat interchangeably because at a normal body temperature, while it may not seem to you if weight is a problem for you, both fats and lipids are liquids. Lipids are generally measured in the blood, while fat is stored in “communities” within cells called adipocytes.

There are two major types of fats—saturated fats and unsaturated fats. The term “saturated” refers to the type of bond between carbon atoms found in lipids and fats—saturated fats have single-bonded carbons, while unsaturated fats have some double-bonded carbon atoms.

Saturated Fats come primarily from animal sources, but a few non-animal sources (coconut oils and palm oils) contain relatively high levels of saturated fats. A diet high in saturated fats can increase LDL-cholesterol, usually termed “bad” cholesterol. It is the LDL-Cholesterol that is associated with heart disease. It is true that some people can eat a diet high in saturated fats and live to be healthy individuals without any problems. However, we have no way to determine precisely which individual may be able to “get away” with a diet high in saturated fats. Most people on a high animal-fat diet tend to have higher levels of markers for heart disease than those on a lower animal-fat diet.

According to Harvard’s(1) School of Public Health, “cutting back on saturated fat can be good for health(2) if people replace saturated fat with good fats, especially polyunsaturated fats.”

Unsaturated fats are further divided into Monounsaturated fats (MUFAs) and Polyunsaturated fats (PUFAs). Unsaturated fats, in general, may help reduce the risk of heart disease and tend to be anti-inflammatory. (In contrast, saturated fats tend to be inflammatory).

MUFAs include oils from olives, peanuts and canola, nuts, seeds, and avocados. PUFAs include oils from sunflower, corn, and soybean as well as canola oils, some nuts (walnuts), flaxseed, and fish—which brings to mind the omega fats.

Omega fats are PUFAs—there are generally three types:

• Omega-3 fats have a carbon double bond (they are Unsaturated) at the 3^rd carbon away from the end of the molecule. The three main types of omega-3 fats are α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA is found in plants, while both EPA and DHA are found at high levels in fish and algae. Humans can use ALA to make EPA and DHA, but the process is relatively inefficient, and seafood in the form of fish or algae provides a reliable source of these omega-3 fats. Evidence is growing that a diet with adequate amounts of omega-3 fats can reduce the risk of heart disease(3), stroke, and inflammation. There is less evidence for the reduction of risk of cancer, asthma, diabetes, and other diseases, though that evidence is beginning to be available(5). Foods with the highest level of omega-3 fats are fish and algae. Sunflower, flaxseed, corn, canola, and soybean oils, walnuts, and flax seeds. Omega-3 fats tend to flow into biochemical pathways that reduce inflammation.
• Omega-6 fats have a carbon double bond at the 6^th carbon away from the end of the molecule. Food sources are plentiful—most vegetables (and vegetable oils), fruit, nuts, cereals, and grains have a high level of omega-6 fats. Common omega-6 fats include linoleic acid, gamma-linoleic acid (GLA), and eicosadienoic acid. Omega-6 fats tend to flow into inflammatory biochemical pathways. Supplementation is usually not recommended because most diets supply more than sufficient amounts of omega-6 fats, while at the same time, most diets lack omega-3 fats. These are also heart healthy—but should be balanced with enough omega-3 fats—many nutritionists say the ideal balance is about 1:1.
• Omega-9 fats, found in olive oil, vegetables, nuts, and seeds, are MUFA. The omega-9 fats tend to be anti-inflammatory and may help improve insulin sensitivity.

Trans fats are artificially produced fat—it is made by heating vegetable oils with hydrogen gas. The process increases the stability of the fat, preventing rancidness. It also hardens the fat so that it is a solid block at room temperature. Trans fats are the main reason why many nutritionists and healthcare professionals recommend avoiding fast and fried foods—they are used in many fast food (and other) restaurants resulting in often unhealthy foods. Trans fats(1) RAISE the levels of LDL-cholesterol (bad cholesterol) and lower HDL-cholesterol (good cholesterol). They are also inflammatory fats and can worsen obesity, heart disease, stroke, and diabetes—and worsen other diseases.

Cholesterol, LDL, and HDL (Oh—and Triglycerides) are the other types of lipids that you need to understand(6).

• Cholesterolis NOT all bad! Cholesterol is needed to make estrogens, testosterone, Vitamin D, and adrenal corticosteroids. It is vital in cell membrane structure and is needed for membranes to remain flexible. It is also part of cell-to-cell signaling. The amount of dietary cholesterol needs to be controlled, but the biggest factor in blood cholesterol levels appears to be the mixture of fats and carbohydrates in your diet.
• LDL-cholesterolis a form of cholesterol surrounded by Low-Density Lipoproteins (the LDL part). These are “packages” of cholesterol used to transport the fats throughout the body—lipids, fats, and cholesterol alone are NOT soluble in blood, so this is how the body carries the cholesterol in the blood to cells. The analogy often made is that LDL (and HDL—see below) are the oil droplets mixed in with the vinegar in salad dressing. The problem with LDL-cholesterol is that when levels are too high, they “drop out of solution” in the blood and arrange themselves on the inner walls of blood vessels—they deposit as plaques that narrow the inner diameter of blood vessels and block the free flow of blood within those vessels.
• HDL-cholesterol is the “healthy” or “good” cholesterol because HDL-cholesterol acts as a sort of scavenger, snarfing up excess cholesterol from the blood, from LDL-cholesterol, and to some extent, from the LDL-cholesterol deposits that may have formed. HDL stands for High-Density Lipoprotein.
• Triglycerides mostly come from dietary fat and are the main component of body fat. It consists of glycerol bonded to three fatty acids. These fatty acids can be short, medium, long, and very long chains. Triglycerides are a storage form of energy for your cells. High levels of triglycerides can contribute to the plaques formed by LDL-cholesterol.