What Is a Fat Anyway?
Video Transcript
Before I jump into the basic biochemistry of fats, I want you to know that eating naturally occurring fats from both plant and animal sources is good for you! Period! That includes milk, cheese, butter, cream, meat, fish, as well as fats from avocado, seeds, nuts, and other plant sources.
Over the last few decades, people have been taught that saturated fats are from animals and they are bad for you! They have been told that unsaturated fats come from plants and are good for you! None of which is true. Both plants and animals contain combinations of saturated, unsaturated, and polyunsaturated fats, all of which in their natural forms are good for you. They are also important sources of the fat-soluble vitamins A, D, E, and K2 that we just talked about in the previous episode.
In this episode we are going to talk about the biochemistry of a saturated fat and how it differs from an unsaturated fat. You’ll learn about the omega fats and why they are vitally important for your health. Later on, we will discuss the manufactured oils and trans fats that contribute to all the chronic diseases that we are now experiencing. Now onto some fun biochemistry!
With all this talk about the importance of fats, what is a fat anyway? Fats and oils, also known as lipids, are actually variations on just three basic components: Carbon (C4, noted by a black sphere in the model below), hydrogen (H2, which is white), and oxygen (O2, the red hot one!). The structure of a fat is simple as well. The backbone of the fat molecule is a chain of carbon atoms with hydrogen atoms as the side arms and a carboxyl molecule at the end of the chain. A carboxyl molecule (COOH) is a carbon, two oxygens, and a hydrogen bonded together, which gives it the name acid. Thus the name “fatty acid” for a carbon chain with a carboxyl molecule at the end.
What makes each fat molecule different is the bonds between the carbons, the length of the chain, and the arrangement of the hydrogen molecules along the chain. Fats can be saturated, unsaturated, or polyunsaturated. When each of the carbon atoms in the chain is bound with a single bond to hydrogen atoms as the side arms, then you have a saturated fat as in the model above. The black chain of carbons is the backbone, and the white hydrogen atoms are holding hands with the carbon atoms. All the carbons are connected by single bonds and illustrate a saturated fatty acid being “all filled up” or fully saturated.
This carbon-to-carbon single-bond structural backbone gives saturated fats strength and stability. They are more suitable for cooking as they do not break down under heat and are less likely to go rancid. The same structure keeps saturated fat molecules straight so that they stack well, like lumber. Saturated fats pack together so neatly that at room temperature they are semi-solid or solid. Biochemistry is almost as fun as Lego®—adding and subtracting, twisting and turning the atoms to make new fatty acids.
What makes fat unsaturated? These fats have the exact same structure as saturated fats except that one or more of the carbon atoms link to each other with a double bond. A double bond in the chain of carbons puts a bend or a kink in the straight carbon chain that keeps it from packing together as well. Note the one double bond in the unsaturated fat below. Now compare it to the saturated fat with its single bonds that create a more stable structure.
This bendy structure of unsaturated fats allows them to be liquid at room temperature and solid or semi-solid only when refrigerated. A carbon chain that contains one double bond or kink is a mono-unsaturated fat, found in fats such as olive oil and nuts such as almonds, pecans, and cashews. Fatty acid carbon chains with two or more double bonds are known as polyunsaturated fats. Polyunsaturated fats can be found in nuts and seeds as well as eggs and meat.
The different chains of fatty acids—saturated, unsaturated, and polyunsaturated—much prefer being in groups of three instead of hanging out alone. When three different chains of fatty acids are attached to a glycerol molecule, we call it a triglyceride. Looks kinda like a three-prong pitchfork.
Saturated, mono-unsaturated, and polyunsaturated fats are all found in nature, and our diets have always contained all three types of fats. Often they exist together in the same food. Olive oil, for example, contains 15% saturated fat and several polyunsaturated fats. Butter contains 68% saturated fat, and a combo of mono- and polyunsaturated fats.
When we look at this chart of various fats that are color coded, you will notice that each one of the fats contains some saturated fats which are noted in the dark purple: 8% in safflower oil, 15% in olive oil, 19% in peanut oil, 51% in palm oil, and coconut oil with the highest level at 91%. Is it surprising to you that some of the highest sources of saturated fats are from plants instead of animals? Lard from pig fat only contains 43% saturated fats and butter has 68%—both containing much less saturated fat than coconut oil. All fats, whether from plant or animal sources, are composed of both saturated and unsaturated fatty acids.
But what about the omega fats? What are they? Saturated or unsaturated? Omegas 3, 6, and 9 are essential polyunsaturated fats found in nature that have two or more double bonds in the carbon chain. By essential, I mean that your body CANNOT make them; so it is essential that they come from your diet. The numbers in their names indicate the position of the first double bond from the end of the molecule. An omega-3 fat has the first double bond in the 3rd carbon position, omega-6 has the first double bond in the 6th position, and omega-9 (you guessed it) has the first double bond in the 9th position. Such clever biochemists! Omega fats are an integral part of cell membranes throughout the body. They also provide the starting point for making hormones that regulate blood clotting, contraction and relaxation of artery walls, and inflammation.
Now that you understand how they got their names, where do we get the omegas from and why do we care? All of the long-chain omega fatty acids are important for their support of a healthy brain. They are essential for proper functioning of your brain cells and affect both your moods and your cognition. The omega-3 fats are most commonly found in fish, seafood, and grass-fed meats. Both omega-3 and omega-6 fatty acids are found in egg yolks and organ meats. Omega 9 fatty acids are found most commonly in nuts and seeds.
Now you know more than you ever wanted to know about fats. I hope this biochemistry was fun and gave you a better understanding of how we are made. Plus there are so many delicious foods to eat that contain a wide variety of fats from plants and animals. Start enjoying a few of them today!
Until next time, this is Dr. DeLaney reminding you to eat real food!