EVOLVE NUTRITION Foundation WEEK 8:
Welcome to Week 8! To wrap up our in-depth discussion on nutritional building blocks, we are going to focus this week on fats.
First, to be crystal clear: You are not what you eat. Fat does not make you fat! Remember, anything in excess has the ability to be stored as adipose. Yes, even protein. No one nutrient is a "bad guy." We need them all in balance, and want to try to avoid excess.
So what are fats?
Fats are a fantastic energy source, and they play a HUGE role in hormone balance and function. They help our form our brains and our nervous system (kind of important). They also help transport and absorb fat-soluble vitamins, as you remember, because you’re a pro now, those are vitamins A, D, E, and K. Additionally, when you eat and break down fat, the rate that your food digests is slower than without fat. This helps keep you sustained longer.
Fats are broken down in the small intestine by certain enzymes. They are then packaged by the intestinal cells into lipoproteins which allow them to be transported around the body. Some of these lipoproteins are used in cells and hormones throughout the body, while others are sent to the liver and made into the hormone called cholesterol, which we'll discuss below.
Types of fat
Fats are complex molecules of primarily hydrogen and carbon (hydrocarbons). These hydrocarbons combine to form fatty acids, which then further combine to form triglycerides, or are processed by the body to make other molecules such as lipoproteins. The arrangement of these hydrocarbon chains determines what type of fat it is.
The two general group ares: unsaturated fatty acids and saturated fatty acids. Dietary fat is made up of a mixture of monounsaturated fatty acids, polyunsaturated fatty acids, saturated acids, trans fatty acids. The term saturated refers to how many hydrogens are associated with each hydrocarbon chain. "Saturated" means that the fatty acid has hit it's maximum number of hydrocarbon molecules. While this distinction seems theoretical in writing, it's important because it gives the fatty acids a different texture, quality, and function in the body. All of these fats need to be in balance in our diets, and there is no one single fat that should be consumed in solitude.
Unsaturated fatty acids: Liquid at room temperature (unless hydrogenated) and can be broken down into monounsaturated fatty acids and polyunsaturated fatty acids. These help to synthesis HDL, the "good cholesterol."
Saturated fats: Generally solid at room temperature and found in meat, full fat dairy, coconut, and cacao. Research has shown that an increased intake of saturated fat is related to an increase in cardiovascular disease and increased levels of LDL cholesterol.
Trans fats: Most come from food processing and adding hydrogen unsaturated fat, this is hydrogenation. "Hydrogenated oils" are just that: oils that through processing, have had hydrogen atoms added to make them more shelf stable and prevent the fats from going rancid. These are the oils and fats that you want to stay away from. Consuming these can lead to decreased blood vessel elasticity… this is not a good thing. Some trans fats are also found in animal products and do not seem to have the same effects as processed trans fats. In 2015 the FDA concluded that processed trans fats are not GRAS (generally recognized as safe), aka they are banned. Partially hydrogenated oils will also need to be phased out of all food products.
But what about cholesterol?
Remember lipoproteins (if not, scroll up just a bit...). While some travel throughout the body to do a specific job, others are sent to the liver and made into cholesterol. There are a few different types of cholesterol, but for our purposes today, let’s focus on the two main ones. These are low-density lipoproteins (LDL) and high density lipoproteins (HDL). LDL carries adipose and lipid molecules out to the cells of the body, while HDL brings them from the cells back to the liver. HDL is the “good” cholesterol beccause they remove fat molecules from cells and arteries and bring it back to the liver. While LDL does serve a role in balance, we generally want more HDL.
But, the body is complex! As we've mentioned quite a few times, anything consumed in excess will be converted into triglycerides, a building block of adipose tissue. So, let's go back to the fat makes you fat argument. During the low-fat craze of the 70's and 80's, the food industry replaced all fat with sugar. However, this did not help reduce the rates of cardiovascular disease, because when carbohydrates or anything, but especially carbohydrates, sugar, alcohol are consumed in excess, they will be converted into triglycerides. This increases LDL levels, as some of these triglycerides are converted into LDL molecules, throwing off our cholesterol levels and impacting cardiovascular health. This is also the reason why consuming alcohol in excess can lead to fatty liver. In fact, we've found that ingestion of dietary cholesterol from food has less of an effect on cholesterol in our body than excessive sugar, fat, and alcohol consumption. If you're head is spinning, don't worry. The key is balance - no fat or excess fat can send things off course.
How do Cheerios lower my cholesterol?
Well... it's not the cheerios. It's the fiber. There are two types of fiber, soluble and insoluble. Soluble fiber is found in whole grains, seeds, nuts and fruits and vegetables. It is the stuff that makes your oatmeal gel-like if you leave it out too long. Insoluble fiber is all of the structures of the fruits, vegetables, whole grains, nuts and seeds that our digestive system cannot break down. Think of roughage. The gel substance that soluble fiber makes when hydrated, actually bind fats and prevent them from being packaged into cholesterol. Once bound, they are excreted through feces. So, technically Cheerios have some fiber, allowing them to claim that they are heart healthy (although there are much better sources such as whole grains and fiber).
Essential Fatty Acids
The final category of fats that we will discuss today are essential fatty acids. Like essential amino acids, these are unable to be synthesized by the body and thus must be obtained through our diet.
Omega-3’s: When talking about omega-3’s, we are generally referring to eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linoliec acid (ALA). ALA is an omega-3 found in plants, it can be converted to EPA and DHA but the conversion rate is low (2-10% of ALA is converted). This is why it can be very beneficial to obtain it from animal sources (fatty fish) or a supplement. DHA and EPA are essential for optimized cardiovascular health, neurological function and recent research has shown that EPA is important for those who are prone to depression. Omega-3’s are also considered to be anti-inflammatory. This is important for many chronic conditions such as cardiovascular disease and type 2 diabetes.
Here are some sources:
- EPA and DHA: fatty fish such as salmon, sardines, anchovies
- ALA: flax, walnut, chia, hemp
Omega-6's are another type of essential fatty acid that also helps with many essential functions in our body. However, they are pro-inflammatory. Inflammation does serve a purpose in the body: It can help tell the body when something is wrong and trigger our body's natural healing response after an injury. However, if you have too many, you body can feel like your body is constantly in a state of emergency, which is not ideal. So, you need a balance of omega-3’s and omega-6’s. But, our food system does not always look as natured intended. An ideal ratio of Omega-6:Omega-3 is 1:1, but the ratio most commonly found in the standard American diet can be much different this (10:1 or more). As a society, we have not increased our intake of Omega-3's as our processed food consumption has risen, thus altering the ratio. That is why health professionals often focus on increasing omega-3 consumption.
Here are some sources: Palm oil, soybean oil, sunflower oil, canola oil. Almost all Americans get enough without trying, so I wouldn't worry about adding more of these to your diet. If anything, it may be beneficial to decrease the consumption of these fats if you are not regularly consuming fatty fish or an omega-3 supplement.
“But what about the harmful chemicals in our current food system and oceans?” Heavy metals are bound to proteins, not fats. Fish oil is a safe supplement as long as you are obtaining it from a reputable source.
Fats are essential and needed for optimal health. But just like everything else, we need them to be in balance. We cannot only eat saturated fats (animal fats). Sorry you can’t live off bacon and coconut oil. Nor can we only eat unsaturated fats (plant fats). We need a little bit of it all for overall health.
Here is a simple way to think about it: saturated fat gives your vessels and cells structure, but they cannot be too rigid, that is why we need unsaturated fats to make them fluid. You need a working alarm system omega-6’s but you cannot have it going off all the time, omega-3’s.
Finally, whenever consuming fats, just like everything else, you want to get them from whole food sources. Here is a handy reference for fats.
Your habit for this week:
- Avoid any hydrogenated or highly processed fats from your meals this week (those listed by the red "x" in the infographic)
- Try to "stay in the green," getting your fats from whole food sources or select oils.
PLEASE NOTE: If you have any cardiovascular conditions, or a family history of cardiovascular conditions, then your fat intake needs may change. Please consult a dietitian (schedule here) if this is the case!
We'll see you back next week to wrap up our nutrition foundation course!
Concerned or confused about nutrition? Not sure if your current nutritional habits are helping you meet your goals? Feel free to pop in Abby's office, schedule an appointment, or shoot her an email at firstname.lastname@example.org