What is a nutrient?
Since I talk a lot about nutrition, I figured I should explain the most basic term about nutrition, which is a nutrient. Many times, we hear how nutritious is this or that, but do we really know what is a nutrient?
A nutrient is a chemical compound required for the correct function of an organism. Without the appropriate nutrients, we can get extremely sick and even die if a deficiency is not caught on time.
There are two subcategories of nutrients, macronutrients, and micronutrients, both found in food. Macronutrients are complex molecules that we need in large quantities and I'll talk about these in this post. Micronutrients on the other hand are what we know as vitamins and minerals and we need them in small quantities, you can learn more about micronutrients in the following posts:
The three macronutrients we always hear about are: carbohydrates, lipids, and proteins. But I think water should be a macronutrient as well. In this entry I will talk only about macronutrients and someday in the future I will talk about all the micronutrients separately.
Water
We always hear that we like 50% water, but how is that? Well, we have about 37 trillion of cells, and most of the molecules within a cell are water, that is it.
I particularly think that drinking water is good, but we do not need to overdo it, because we get most of our water from the food we eat. Saying that we should drink X amount of water daily is BS. A 2-meter-tall person does not need the same amount of water I do (I am 1.56 m), as well as someone who sweats a lot and someone who does not sweat at all.
Nowadays we do not listen to our bodies and the truth is that they are very smart biological machines. If you don't drink a lot you'll get a headache, that's a sign to drink more and if you drink too much you'll be peeing all day long. Drink water when you are thirsty, learn to listen to your body you don't need science to tell you how much you should drink.
If you paid attention in your chemistry classes, you should know that water and salt get along well, you can easily dissolve salt in water. You should also know that regular salt is also called sodium chloride (NaCl) which is in the form of Na+ and Cl- in water, by the way sodium is a required micronutrient. If you drink a lot of water, what you are doing is flushing that sodium through urine. On the other hand, if you eat too many electrolytes, for example salt, then you will get thirsty, you will drink more water to flush that sodium out of your body. See? Your body is smart, it regulates itself, you just have to listen to it.
Carbohydrates
There are three types of carbohydrates: starches, sugars, and fibers. Let's talk about fiber first since they are totally different to the other two.
Fiber
Human beings cannot digest fiber, this is because we lack the enzymes to do so. An enzyme is a catalyst, without one the reactions inside the body would take years to be carried out, we would be dead by then, if you want to know more about enzymes you can read this post: What is an enzyme and what it does. Humans do not have cellulase which is the enzyme to digest fiber and that is why it goes through us, but we are not made of it. Even though it passes through us, it does not mean it has no use.
There are soluble and insoluble fibers, the soluble ones dissolve in water and form a kind of gel that help us feel satiated, help the food go through the intestine slowly so nutrients can be absorbed better and to soften stools. Insoluble fiber adds consistency to feces and attracts water. To me the most important thing about fiber is that it feeds good bacteria in our intestines. It is important for our health to have a healthy microbiome, diverse and abundant and to do so we need to feed it well.
Although I think that fiber is important to feed the bacteria in our gut, I do not think it is mandatory to eat it. It all depends on our genes and our life habits; some people get better result eating more fiber than other. Once again, listen to your body if you are bloated or constipated, do something to change it! Either eat less or more fiber to see how you feel, it is a little tricky to know how much fiber you can eat because too little or too much can make you constipated. What I would say though is that 0 fiber after a few days will give you 0 bloating, so maybe start there.
Starches and sugars
From all the macronutrients this one is the most useless. There are essential fatty acids and amino acids, but there are none essential carbohydrates.
When we use the word sugar, we usually use it to refer to the sugar we use to sweeten things up like tea or cakes, but there are a few types of sugar. For example, sucrose is the white crystal sugar and lactose is the sugar found in milk.
Sucrose and lactose are disaccharides, which means that they are formed by two other simpler sugars called monosaccharides (what you see as a hexagon in the image). Starches on the other hand are larger molecules formed by a bunch of monosaccharides. The next image is a starch called amylose, the parenthesis [ ] means that that piece of molecule is repeated 300 to 600 times.
Our bodies have enzymes to break those sugars and starches into smaller molecules that our cells can use. For example, lactose is broken into galactose and glucose thanks to the lactase enzyme, if your body does not produce lactase, then you are lactose intolerant.
Starches need the enzyme amylase, when starches are digested, they are broken into a bunch of glucose, at the end of the digestion a potato, bread or refined sugar are the same, just plain glucose. This glucose ends up in the bloodstream and thanks to insulin it is able to create energy inside the cells. Excess glucose is stored in two ways in the body, as glycogen which is a molecule found in the liver and in the muscles and as fat, the body transforms sugar into triglycerides which are fats that are stored in the adipose tissue.
Speaking of fat, let’s talk about them.
Fats
Our bodies store energy as fat, because within a small volume it can store a lot of energy. There are four types of fat, polyunsaturated, monounsaturated, saturated and trans.
In the image you can see a saturated fat, between two carbon atoms (C) there is a simple bond (one dash), these fats can be recognized at simple sight because they are solid at room temperature, some examples are coconut oil and any animal fat such as tallow or lard. Then we have an unsaturated fat, specifically a monounsaturated one, because it only has one double bond (two dashes). Examples of unsaturated fat are avocado or olive oils. If a molecule has more than one double bond, then it is a polyunsaturated fat.
Trans fats, these are not natural
Of all fats that are out there, you should never ever eat trans fats, there are a human creation and our bodies do not know what to do with them, producing detrimental effects to our health. They were created to produce a solid fat at room temperature from vegetables oils. Nowadays, margarines and other solidified vegetables oils go through an extra process to not make them trans, 15 years ago they did not know trans fats where bad, so we used to eat plenty of them thinking it was healthier than butter.
Natural fats (cis)
Coming back to natural fats, the fact that some of them have double bonds makes them less stable, the more double bonds a molecule has the more unstable it is. Less stable means that it reacts more easily and doing so they oxidize themselves. Oxidized molecules can cause a lot of problems inside the body and are one of the reasons we age and that is why you hear a lot about antioxidants. Therefore, frying things with saturated fats like coconut oil or animal fats is much healthier than frying with vegetables oil. The simple bonds found in saturated fats, makes them more stable to heat, keeping their integrity and producing fewer toxic products. On the contrary, oils like sunflower or even worst corn oil have a lot of polyunsaturated fats. If you want to know more about this you can read this: The best fats to cook.
As well as carbohydrates, fats need an enzyme called lipase to be digested, when the lipase does his job, the fatty acids enter the bloodstream where they are delivered to the cells to be part of different metabolic processes. In the future I will talk about what are the different functions of fats in the body.
Fats are essential for a correct body function because the cells in our bodies are made from fat and proteins, without fats we would die. Brain is made up to 60% of fats so we need to consume them daily. If you eat too little fat, think about it twice because there are two essential fatty acids that we cannot produce, linoleic acid and alpha-linolenic acid.
Lastly, I would like to add that oils are a refined and processed product created by humans. It is better to eat an avocado or an olive rather than eating their respective oils, because at least those are whole foods with more nutrients even.
Proteins
A protein is a long chain of different amino acids bonded together, unlike fats and carbohydrates which are made only from carbon, oxygen and hydrogen atoms, proteins also have nitrogen. Humans need 20 different amino acids, 9 of them are essential which means we need to eat them through the diet.
In an omnivore diet you could only eat pork for the rest of your life, and you would get all 9 essential amino acids. In a vegetarian or vegan diet, you wouldn’t have all of them just eating beans, you would need to eat different protein sources to get all of them. That is why animal protein is called a complete protein and plant proteins are incomplete, except for quinoa, I think.
Like the other macronutrients, you need an enzyme to digest proteins called protease. This enzyme cut the long chain of amino acids into the different amino acids we need. Here you have a list of the 20 amino acids separated in essential and not essential:
Essentials:
- Phenylalanine
- Valine
- Threonine
- Tryptophan
- Methionine
- Leucine
- Isoleucine
- Lysine
- Histidine
Not essentials
- Alanine
- Aspartic acid
- Asparagine
- Glutamic acid
- Serine
- Arginine
- Cysteine
- Glycine
- Glutamine
- Proline
- Tyrosine
When the chain is broken down and amino acids are released, these go to the bloodstream where they are used to create new muscle and repair tissues. I will talk more in depth about proteins in a future.
That is, it, I hope it was not too much information at once. If you think I should explain it better or you have any question, please let me know. If it is necessary, I will rewrite this post to make it more understandable.
Thanks for Reading it I hope it is useful!
