Nutrition, part 2: Macronutrients - Carbohydrates, Lipids, Protein
by Cathy Parkes July 16, 2021 Updated: August 09, 2023 6 min read
Learn all about macronutrients (macros), as well as LDL vs. HDL cholesterol, simple vs. complex carbohydrates, soluble vs. insoluble fiber, saturated vs. unsaturated fat, and the steps in protein metabolism!. This series follows along with our Nutrition Essentials for Nursing Flashcards which are intended to help RN and PN nursing students study for nursing school exams, including the ATI, HESI, and NCLEX.
Nutrition plays a key role in patient wellness, and patient teaching regarding nutrition is a key part of EVERY nurse’s job. These flashcards will help you understand the basics of nutrition, along with key nutritional and lifestyle considerations for common health disorders.
When you see this Cool Chicken, that indicates one of Cathy's silly mnemonics to help you remember. The Cool Chicken hints in these articles are just a taste of what's available across our Level Up RN Flashcards for nursing students!
Carbohydrates are the primary source of energy for the body; they control blood glucose levels as well as insulin metabolism.
You can find carbohydrates in a variety of food sources, which include vegetables, fruits, dairy products, as well as whole grains. Sugar is also a carbohydrate.
There are simple carbohydrates as well as complex carbohydrates.
Simple carbohydrates are easy to digest, and they provide quick energy, and they also cause your blood glucose levels to go up very quickly. For example, fruit juice, honey and candy are simple carbohydrates.
Complex carbohydrates take longer to digest, cause a slower increase in blood glucose levels, and provide more fiber. Examples of complex carbohydrates include apples, brown rice, and lentils.
Glycogen is another type of carbohydrate energy that is stored in the liver and in muscles. It is broken down and released in the bloodstream when your body needs energy through a process called glycogenolysis.
If you break down the word glycogenolysis into its parts, you get "glyco-" (having to do with glucose or sugar) and "-lysis," which means breaking down. We created our Medical Terminology flashcards to make breaking down words into their parts easy, so you never have to be confused by an unfamiliar word on an exam!
For example, if you are working as a nurse, and you have a 12-hour shift and skip lunch, when your blood glucose levels get low enough, your body will start breaking down your stored glycogen to help provide glucose for your muscles and brain. Glycogen stores also get depleted, for example, when running a marathon.
Fiber is a type of non-digestible complex carbohydrate, which is important for the body as it provides a number of health benefits.
The benefits of fiber include an increase of healthy bacterial growth in the colon; softening and bulking of the stool to allow for easier bowel movements; stabilization of blood glucose levels; and a decreased risk of diverticulitis, hemorrhoids, colorectal cancer, and coronary artery disease.
Soluble vs. insoluble
The difference between soluble and insoluble fiber is that soluble fiber dissolves in fluid and is derived from the inner flesh of plants, while insoluble fiber does not dissolve in fluid and is derived from the outer skin of plants. So, if you had a parent that told you "the skin has all the nutrients," in an effort to get you to eat the whole fruit or vegetable growing up, while this isn't exactly the same thing, the outer skin of plants does contain insoluble fiber that the inside of plants doesn't!
Soluble fiber sources include oats, barley, beans and fruit, while insoluble fiber comes from whole grains, nuts, seeds, vegetables and potatoes.
The current recommended fiber intake level is 38 grams per day for men and 25 grams per day for women.
Lipids (fats) represent the main source of stored energy in the body, and they help provide cell structure and function. Your cell membrane is a phospholipid bilayer, so lipids are a key component. Lipids are important for the body's temperature regulation and organ protection.
Lipids can be found in food sources like fats, oil, dairy and meat.
There are several types of dietary lipids that are important to know about for nutrition in nursing; saturated fats, trans fats, and unsaturated fats.
Saturated fat is mostly found in animal products, like meat or dairy. Studies have shown that saturated fats, in general, can cause an increase in LDL cholesterol levels (which we will explain in the next section). Saturated fats consumed in excess can increase a person's risk for heart disease.
Trans fats are usually found in processed foods and shortening. If you read an ingredient label and you see the words "partially hydrogenated oil," then it's likely that product has trans fat.
Trans fats have been shown to increase the levels of LDL cholesterol, and actually decrease the levels of HDL cholesterol (which is the good kind of cholesterol)! The addition of artificial trans fats to foods was banned by the FDA in 2015 and foods manufactured after 2018 (later extended to 2020) are not allowed
Unsaturated fats are considered "heart-healthy" fats and are found in foods like avocados, nuts, seeds, olive oil, and vegetable oils.
As a general matter, medical experts recommend consuming more "heart-healthy fats" than saturated fats, and steering clear of trans fat.
Cholesterol is a waxy, fat-like substance that is produced by the liver and is also found in dietary sources, and it plays an important role in the body. Cholesterol is needed as a cell membrane component. It's needed for vitamin D synthesis, hormone synthesis, and digestion.
LDL vs. HDL Cholesterol
Cholesterol can be broken down into two types: low-density lipoproteins (LDLs) and high-density lipoproteins (HDLs). LDL is known as the "bad" cholesterol and HDL is known as the good cholesterol.
L for Lethal/Lousy (i.e., bad). H for Happy (i.e., good).
The recommended intake of cholesterol is under 300mg per day; under 200mg for people who are at high risk for heart disease.
Protein is our third macronutrient (carbohydrates, fat, and protein). Protein is very important in the body, and is used for tissue building, tissue repair, wound healing, immune system functioning, and energy.
Protein can be found in food sources like seafood, meat, poultry, eggs, soy, nuts, seeds, and dairy products.
Proteins are made up of amino acids, and there are 9 essential amino acids and 11 non-essential amino acids.
The word essential in amino acid classification refers to a need for dietary intake. The 9 essential amino acids cannot be made from the body, and it is essential that we get these amino acids from food sources. The other 11 amino acids can be produced by our bodies under normal physiologic conditions, so it is not essential that we get them from our diet.
It's essential to eat essential amino acids.
Protein can be categorized into complete proteins, incomplete proteins, and complementary proteins—this refers to the amino acid makeup inherent in that protein.
Complete proteins are proteins that contain all 9 essential amino acids. Complete proteins usually come from animal sources, like meat and dairy, but also from soy.
Incomplete proteins are proteins that lack one or more of the 9 essential amino acids. Incomplete proteins are often paired with other, different incomplete proteins, that together can create a complementary protein.
A complementary protein is a phrase that refers to a combination of incomplete proteins—each protein by itself may be lacking in one or more of the essential amino acids, but the other protein in the pair does cover those amino acids, so together they cover all 9 essential amino acids and make a complete protein.
Rice and beans is a classic example of a complete protein. Rice and beans, each by themselves, are incomplete proteins, but together they contain complementary proteins, so if you consume them together, you get all of the essential amino acids.
Protein metabolism is an overarching term referring to the cyclical creation and breakdown of protein by the body. The processes that you will need to know about in your nutrition studies are grouped into anabolism, catabolism, and nitrogen balance.
Anabolism is protein synthesis, which is when the body assembles amino acids to create proteins.
Anabolism Adds Amino Acids together.
Catabolism is where proteins are broken down for energy.
Catabolism is the catastrophic breakdown of proteins.
Nitrogen balance is the body's balance between anabolism and catabolism. Healthy adults should have a neutral nitrogen balance.
A positive nitrogen balance occurs when protein synthesis is greater than protein breakdown. This means the body is creating proteins faster than it is using proteins for energy. This can happen during childhood and adolescent growth spurts as well as during pregnancy.
A negative nitrogen balance occurs when protein breakdown is greater than protein synthesis. This means the body is breaking down proteins for energy faster than it is creating new proteins. This can happen to people experiencing starvation (insufficient calorie intake) or in severe injuries like burns, where the body is breaking down large amounts of protein to heal itself.
Hi, I'm Cathy with Level Up RN. And in this video, I am going to go into more detail about our macronutrients. So this includes carbohydrates, lipids, and protein. And at the end of this video, I'm going to give you a little quiz, a little knowledge check to be sure you've been listening.
And if you find value in our videos here at Level Up RN, be sure to subscribe to our channel, and tell your classmates and friends in nursing school about us.
Alright. Let's start off talking about carbohydrates.
Carbohydrates are our primary source of energy for the body. And they control blood glucose levels as well as insulin metabolism.
You can find carbohydrates in a variety of food sources, which include vegetables, fruits, dairy products, as well as whole grains.
There are simple carbohydrates as well as complex carbohydrates.
Our simple carbohydrates are easy to digest, and they provide quick energy, and they also cause your blood glucose levels to go up very quickly.
So examples of simple carbohydrates can include fruit juice, honey, and candy.
Then we have our complex carbohydrates which provide more fiber, which we'll talk about in just a minute here. They take longer to digest and they cause a slower increase in blood glucose levels.
So some examples of complex carbohydrates include apples, brown rice, and lentils.
Another type of carbohydrate energy that I want to talk about here is glycogen.
Glycogen is stored carbohydrate energy in the liver and in the muscles. And it is broken down and released in the bloodstream when your body needs it through a process called glycogenolysis. So if you're working as a nurse on a floor and you're working a 12-hour shift, and maybe for a big chunk of that, you're not eating anything, when your blood glucose levels get low enough, your body will start breaking down this glycogen to help provide glucose for your muscles, your brain, for basically your whole body. So again, glycogen is that stored carbohydrate energy.
Okay. So as I mentioned before, complex carbohydrates are often richer in fiber.
And fiber is so important for the body, and it provides a number of health benefits.
This includes an increase in healthy bacterial growth in the colon.
It helps to soften and bulk the stool to allow for easier defecation.
It helps to stabilize blood glucose levels.
It decreases the risk for diverticulitis, for hemorrhoids, for colorectal cancer, as well as coronary artery disease.
So getting enough fiber is definitely important. Current recommendations are for 38 grams per day for men and 25 grams per day for women.
Alright, let's now talk about our next macronutrient, which are lipids.
So lipids represent the main source of stored energy in the body, and they help provide cell structure and function.
Your cell membrane is a phospholipid bilayer, so lipids are going to be a key part of that.
They are also super important for temperature regulation as well as protection for the organs.
You can find lipids in food sources such as fats, oil, dairy, and meat.
And within lipids, we have saturated fats, trans fats, and unsaturated fats.
So saturated fats are mostly found in animal products, such as meat or dairy. And saturated fats in general can cause an increase in LDL levels - which we'll talk more about LDL and HDL here shortly - and they also increase an individual's risk for heart disease.
Trans fats are mostly found in processed foods. So if you read the ingredient label and you see the words partially hydrogenated oil or shortening, then chances are that that product has trans fat.
Trans fats have been shown to increase levels of LDL and to decrease HDL levels, which is the good cholesterol, which we'll talk about in just a minute.
And then we have unsaturated fats. Unsaturated fats are considered our heart-healthy fats. So they're found in foods such as avocados, nuts, seeds, and olive oil as well as vegetable oil.
So in general, the medical experts really emphasize that we consume more of those heart-healthy unsaturated fats versus the saturated and trans fats.
Alright, let's talk a little bit more about LDL and HDL, which are types of cholesterol.
Cholesterol is a waxy, fat-like substance that is produced by the liver and is also found in dietary sources, and it plays an important role in the body.
It's needed as a cell membrane component. It's also needed for vitamin D and hormone synthesis as well as digestion.
So we have our high-density lipoproteins and our low-density lipoproteins.
So our LDLs are those low-density lipoproteins. Those are our bad cholesterol, so L for LDL, L for lousy.
Our high-density lipoproteins, or HDL, those are our good cholesterol, so H for HDL and H for happy. That's how I remember the difference between those two.
So in terms of the recommended intake of cholesterol per day, in general, it's recommended that our cholesterol intake stay below 300 milligrams per day.
However, for individuals who are at high risk for heart disease, recommendations are to keep those levels below 200 milligrams per day.
Alright, now let's talk about our third macronutrient, which is protein. Protein is very important in the body. It's needed for tissue building and repair. So as a wound nurse, that's one of the first questions I ask the patient, is, "How is your nutrition? How is your protein intake?" Because having sufficient protein is so important for wound healing.
Protein is also needed for immune system functioning as well as energy.
You can find protein in food sources such as seafood, meat, poultry, eggs, soy, nuts, seeds, and dairy products.
So proteins are made up of amino acids, and there are 9 essential amino acids and 11 non-essential amino acids.
So the 9 essential amino acids cannot be made by the body. We have to get them from food sources. So the little Cool Chicken hint that I have on this particular card is that it's essential to get essential amino acids from your diet.
On the other hand, non-essential amino acids can be produced by the body under normal physiologic conditions.
So when it comes to eating protein, we have complete proteins, which contain all of the 9 essential amino acids. And these complete proteins usually come from sources such as animal sources like meat ,as well as soy. Then we have our incomplete proteins.
So an incomplete protein means that this protein source lacks one or more of the essential amino acids that we need. However, we can eat complementary proteins.
So if we have this incomplete protein over here which is lacking in 2 essential amino acids, and then we have this other incomplete protein which is lacking in different amino acids that are essential, if we eat these two foods together, then we get all of the essential amino acids we need.
So, for example, rice and beans. Rice and beans by themselves are incomplete proteins, but they contain complementary protein, so if you eat those two things together, you get all of your essential amino acids.
The last thing I want to touch on in this video is protein metabolism and the concepts of anabolism, catabolism, and nitrogen balance.
So anabolism is where we are assembling amino acids to create proteins. So we are doing protein synthesis.
Catabolism is where we are breaking down proteins for energy. And there are some great Cool Chicken hints here to help you remember those two things on card seven.
The nitrogen balance is the balance between anabolism and catabolism. And in a healthy adult, we expect a neutral nitrogen balance.
However, there are some periods of time where we may see a positive nitrogen balance. So a positive nitrogen balance happens when protein synthesis exceeds protein breakdown.
This can happen during growth spurts in your teenagers and it can happen during pregnancy.
On the other hand, sometimes we see a negative nitrogen balance. This is where protein breakdown exceeds protein synthesis.
And this can be seen in patients who are starving, who basically are having insufficient calorie intake, and it can also be seen in patients who have severe injuries such as burns.
Okay, you guys ready for your quiz? First question. What do you called stored carbohydrate energy in the liver and muscles?...If you said glycogen, you are correct.
Okay. Second question. Which macro nutrient is the main source of stored energy in the body?...All right. The answer is lipids.
And then last question for you guys. What do you call the breakdown of protein for energy?...It is catabolism.
Hope you got those three questions right. If not, go back and review my video. It'll be here when you need it. And definitely take those cards on a walk because repetition is key with this stuff.
So thanks so much for watching. If you enjoyed this video, leave me a comment. And if you have any suggestions for improvement, would love to hear those too. Take care!
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