If you’re like me, you probably use the words “vitamin,” “nutrient,” and “nutrition” almost interchangeably. Most of us grow up learning things like “vitamin C prevents scurvy” and “you get vitamin D from the sun” and “fish are high in omega-3s, which are good for you” without really stopping to think about how all these concepts work together. What is nutrition and what are nutrients anyway?
Here’s how to understand nutrients in just a few minutes. I’m trying to present this in a way that anyone can easily remember; let me know in the comments if I succeeded.
A simple framework
A “nutrient” is a chemical that your body requires to survive, grow, and/or reproduce. That’s it. If you don’t have enough nutrients, you cannot survive, grow, and/or reproduce.
Nutrients can be split into two categories: Essential and Non-essential
Essential nutrients are chemicals that your body cannot get enough of on its own (either because your body cannot make them at all, or because it cannot make them as fast as it consumes them). Therefore, it is essential that you get these nutrients from your diet in order to survive, grow, and/or reproduce.
Non-essential nutrients are chemicals that your body can produce on its own. While you can also get them from your diet (and should!), it is not essential that you do. (Technically, places like Wikipedia don’t define non-essentials exactly this way, but we’re after simplicity here. It’s at least 80% right.)
All the other classifications of nutrients sort of nest underneath the essential/non-essential classification, like macro-/micro-nutrients (macro = you need lots of it, micro = you need only a little bit of it) or organic/inorganic nutrients (organic = nutrient is made from carbon/hydrogen; inorganic = made of other elements).
So remember:
Nutrients are chemicals your body requires.
They’re essential if you can’t make enough of them yourself, so you have to get them from your diet or the sun (or “exogenously,” if you want to be pretentious about it).
What are these essential nutrients?
Really, it’s just the collective of the nutritional advice you’ve probably read or heard about your whole life. But if you’re like me, no one has ever set it out in a logical, simple framework before.
It’s actually pretty simple. You can break up the essential nutrients into four categories: vitamins, minerals, fatty acids, and amino acids.
Category 1: Vitamins (13 considered essential)
Vitamins are just “organic chemicals that your body needs.” Honestly, the whole set of “vitamins” seems like a mishmash of different types of chemicals all thrown together. Science has progressively added to and shortened the list of vitamins over time. Which probably means that science isn’t done modifying this list yet, by the way.
The word “vitamin” itself is a shortened form of two words, “vital amine” (i.e., amines [a type of chemical] that are vital because your body doesn’t make enough of them). Vitamins used to be called “vitamines,” but then science found that the vitamins they were discovering weren’t all amines after all. So they grouped all the chemicals together anyway, dropped the “e” from “vitamine,” and started plastering it on the back of cereal boxes. Not exactly, but close.
The 13 essential vitamins are the stuff you’ve heard about since you were a kid: vitamins A, C, D, E, K, and the eight B vitamins (B1-B3, B5-B7, B9, and B12).
Two important things to remember about vitamins:
Each vitamin is actually a group of related chemicals. So there isn’t one single vitamin A; it’s actually several chemicals that are very similar to each other.
Some vitamins are water-soluble (vitamins B and C), meaning you need water to absorb them, and others are fat-soluble (vitamins A, D, E, and K), meaning you need to absorb them through fat (and that they can be stored in your body fat for later use).
A fun fact: There used to be B vitamins for all the missing numbers (B4, B8, etc.) and the missing letters (vitamin F, vitamin G, etc.) back in the 1900s. But then science later found that our bodies could manufacture these chemicals, so they stopped being vitamins. Sort of like Pluto stopped being a planet.
(I still feel bad about Pluto, but vitamin F has always been dead to me).
Category 2: Minerals (at least 14 considered essential)
These are the inorganic elements or molecules your body needs (i.e., anything that isn’t a mixture of carbon and hydrogen atoms). Minerals are things like calcium, selenium, copper, and potassium. These elements are present in soil, they’re taken up by plant roots as plants grow, and then either eaten by us directly, or eaten by the animals (that we later eat) and stored inside their meat.
At least 14 of them are considered essential, and there are a couple others that are components of vitamins (like cobalt for vitamin B12), so that’s why I said “at least.” You’ll often see these referred to as “trace” minerals, because the amount we need can be vanishingly small.
Category 3: Fatty acids (2 considered essential)
Fatty acids include the omega-3s and omega-6s you’ve probably heard about non-stop since the late 1990s or early 2000s, as well as a bunch of other types.
There are multiple types of fatty acids, and they’re broken down into a few categories:
Saturated and Unsaturated, which tells you whether the carbon molecules in the fat are saturated with hydrogen atoms (no room for more) or not. Animal fats tend to be saturated, solid at room temperature, and stay fresh longer; plant fats tend to be unsaturated, liquid at room temperature, and go rancid faster. Within the unsaturated category, there’s monounsaturated (room for one more hydrogen) and polyunsaturated (room for more than one hydrogen).
Short-, Medium-, and Long-chain, which tells you literally how long the molecule is by how many carbon molecules are lined up into a chain in its molecular “tail.” Short-chains have five or fewer carbons, medium-chains have 6 to 12, and long-chains have 13 or more.
The two essential ones are alpha-linolenic acid (ALA), an omega-3, and linoleic acid (LA), an omega-6.
If you’re into this sort of thing, the “omega-ness” of an acid describes how far from the tail end of a fatty acid there exists a double carbon bond. An omega-3 acid has a double bond three carbons away from the tail; an omega-6 has one six carbons away. There are omega-7s too, and omega-9s, and others, but they don’t have good PR teams.
(And if in reading that last paragraph you observed that any omega-X fatty acid must be unsaturated by definition, you, friend, are an uncannily savvy reader. Tip of my hat to you.)
Category 4: Amino acids (9 considered essential)
Finally, we come to the amino acids — precursors to essential proteins in our bodies. There are 21 amino acids common to life forms (according to Wikipedia), and nine of them are essential. The most well-known of the essential ones is tryptophan, of Thanksgiving food coma fame.
They’re all present in meat, and partially-present in plants, which is why vegetarians mix protein sources (like rice and beans) to get the full complement of aminos.
Alright, alright… tell me what I’m supposed to remember.
If you remember nothing else, keep these four points in mind and you’ll have a good beginner’s grasp of nutrients:
A nutrient is a chemical your body must have to survive, grow, and/or reproduce.
An essential nutrient is a nutrient your body can’t produce enough of on its own, so you have to get it from your diet (or the sun).
There are four types of essential nutrients: vitamins (13), minerals (14), fatty acids (2), and amino acids (9).
Now go slay at your local med school’s pub trivia.
So basically there are essential nutrients, essential minerals and essential vitamins and our body needs all of them to survive 🤯🤯🤯