Food · lesson 1 of 12
What micronutrients are — and why 'micro' isn't 'minor'
Cofactors that make your enzymes work: macro fuel vs micro spark plug.
5 min read · reviewed October 2026
Your diet has two layers. Macronutrients — protein, carbs, fat — are the fuel and building blocks, measured in grams and hundreds of calories. Micronutrients — vitamins and minerals — are measured in milligrams or micrograms and supply zero calories. Yet without them, the fuel can't be burned.
Think of it this way: macros are the gasoline, micros are the spark plug. You can have a full tank and go nowhere if the spark is missing.
Micros are cofactors
Most vitamins and minerals work as cofactors — helper molecules an enzyme needs to do its job. Magnesium, zinc, and the B-vitamins each unlock entire families of reactions. Run low and dozens of processes slow at once, which is why deficiency symptoms are so vague and wide-ranging.
Magnesium acts as a cofactor for how many distinct enzymatic reactions in the human body?
Somewhere between 10 and 600 reactions.
Reveal the answer →
~300+ reactions
Magnesium is required for 300+ enzymatic reactions — including every step that uses ATP (your energy currency), DNA and protein synthesis, and muscle and nerve function. One mineral, hundreds of jobs. That breadth is exactly why a single shortfall produces such a scattered list of symptoms.
Vitamins vs minerals
Vitamins are organic molecules (they contain carbon) made by living things — plants, animals, microbes. They're more fragile: heat, light, and air can degrade them.
Minerals are inorganic elements that come from soil and water and end up in food. They're indestructible — you can't cook the iron out of spinach — but how well you absorb them varies enormously.
'Essential' means your body can't make it
An essential nutrient is one you must get from food because your body either can't synthesize it at all, or can't make enough. That's the whole reason these show up on labels and RDAs exist — there's no internal backup supply. (Vitamin D and niacin are partial exceptions: your skin makes some D from sunlight, and you make a little niacin from the amino acid tryptophan.)
Why does a single mineral deficiency often cause many unrelated-seeming symptoms?
- Minerals are stored in fat and leak out slowly
- Each micronutrient is a cofactor for many different enzymes at once
- The body randomly shuts down organs to conserve energy
- Symptoms are mostly psychological
Show the answer →
B.Each micronutrient is a cofactor for many different enzymes at once
Because one micronutrient typically powers dozens or hundreds of reactions across different systems, a shortfall slows all of them simultaneously — producing fatigue, mood changes, poor sleep, cramps, and more, with no single obvious cause.