Vitamins and minerals are needed in amounts so small they're measured in milligrams or micrograms — yet a shortage of even one can affect vision, bones, immunity, or the blood itself. This article maps out every major vitamin and mineral, what each one actually does, and why "small amount" doesn't mean "small importance."
A single almond contains almost no calories worth mentioning, yet it delivers vitamin E, magnesium, and manganese — nutrients the body cannot produce and cannot do without. Vitamins and minerals, together called micronutrients, don't power the body the way carbohydrates or fats do. Instead, they make nearly every other process in the body possible, from turning food into energy to healing a cut.
Micronutrients are needed only in milligram or microgram amounts — a tiny fraction of the grams of carbohydrate, protein, or fat eaten daily. They provide no calories of their own. Instead, they act as helpers: cofactors and building blocks that allow the body's chemical reactions, structures, and defences to function properly. There are two categories: vitamins, which are organic compounds, and minerals, which are inorganic elements drawn originally from soil and water.
Of the 13 recognised vitamins, each is classified by how the body absorbs and stores it:
| Group | How It's Stored | Key Trait |
|---|---|---|
| Fat-soluble (A, D, E, K) | Stored in body fat and the liver | Absorbed alongside dietary fat; excess can build up to toxic levels over time |
| Water-soluble (B-complex, C) | Not stored — excess leaves the body in urine | Needs regular, near-daily replenishment through food |
This is why taking a very large single dose of vitamin A can be risky over time — it accumulates in the liver — while taking too much vitamin C in one sitting is rarely dangerous, since the surplus is simply flushed out in urine within a day or so.
| Vitamin | Main Role | Deficiency Effect |
|---|---|---|
| Vitamin A | Vision, immune function, skin health | Night blindness, weakened immunity |
| Vitamin D | Calcium absorption, bone strength | Rickets in children, weakened bones in adults |
| Vitamin E | Antioxidant, protects cell membranes | Nerve and muscle weakness (rare) |
| Vitamin K | Blood clotting | Excessive bleeding and bruising |
| Vitamin C | Immune support, collagen production, iron absorption | Scurvy — bleeding gums, poor wound healing |
| Vitamin B12 | Red blood cell formation, nerve function | Anaemia, nerve damage |
| Folate (B9) | Cell division, especially in pregnancy | Neural tube defects in early pregnancy |
Minerals split into two groups based on how much the body needs each day:
Macrominerals — calcium, phosphorus, magnesium, sodium, potassium, chloride, and sulfur — are needed in amounts of 100 milligrams or more per day. Trace minerals — including iron, zinc, iodine, copper, manganese, and selenium — are needed in much smaller amounts, typically under 15 milligrams daily, yet are just as essential.
| Mineral | Main Role | Deficiency Effect |
|---|---|---|
| Calcium | Bone and teeth structure, muscle and nerve signalling | Weak bones, osteoporosis risk |
| Iron | Carrying oxygen in red blood cells | Iron-deficiency anaemia, fatigue |
| Iodine | Thyroid hormone production | Goiter, hypothyroidism, developmental issues |
| Zinc | Immune function, wound healing, growth | Slow healing, weakened immunity |
| Potassium | Fluid balance, nerve signals, heart rhythm | Muscle weakness, irregular heartbeat |
| Sodium | Fluid balance, nerve transmission | Rare deficiency; more commonly overconsumed |
Iodine deficiency is one of the most common preventable causes of intellectual disability worldwide, which is exactly why many countries fortify table salt with iodine — a low-cost public health measure that virtually eliminated goiter in populations where it was once common.
Both are essential and both are needed in small amounts, but they differ at a chemical level. Vitamins are organic compounds — meaning they're built around carbon and can be broken down by heat, light, or air, which is why overcooking vegetables can destroy some of their vitamin content. Minerals are inorganic elements — they don't break down with cooking, though they can leach out into cooking water.
Even in places with abundant food, micronutrient deficiencies — sometimes called "hidden hunger" — remain common. This usually isn't about too little food, but too little nutrient variety: diets built heavily around processed or refined foods can supply plenty of calories while falling short on vitamins and minerals. Restrictive diets, certain medical conditions, and specific life stages such as pregnancy also raise the risk of falling short on particular micronutrients.
Vitamins and minerals rarely announce themselves the way hunger or thirst do — a mild shortfall can persist quietly for months before symptoms appear. Understanding which nutrients fall into which category, what each one actually does, and where deficiencies commonly show up gives you the tools to spot gaps in a diet long before they become serious problems.
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