| Total essential vitamins | 13 (National Institutes of Health, Office of Dietary Supplements) |
| Essential dietary minerals | ~16 recognized (General nutrition science consensus) |
| Most common US micronutrient shortfall | Vitamin D, calcium, potassium, and iron (2020–2025 Dietary Guidelines for Americans) |
| Fat-soluble vitamins | A, D, E, K |
| Water-soluble vitamins | C, B1, B2, B3, B5, B6, B7, B9, B12 |
What Are Micronutrients?
Your body needs two broad categories of nutrients to function: macronutrients (carbohydrates, proteins, and fats) and micronutrients — the vitamins and minerals required in smaller amounts but no less important. If you want a grounding in macros first, see our guide to macronutrients.
The defining feature of micronutrients is that the human body cannot synthesize most of them in adequate quantities on its own. That makes diet — and in some cases supplementation — the only reliable source. Deficiencies can impair everything from immune response and bone density to nerve signaling and energy metabolism.
| Total essential vitamins | 13 (National Institutes of Health, Office of Dietary Supplements) |
| Essential dietary minerals | ~16 recognized (General nutrition science consensus) |
| Most common US micronutrient shortfall | Vitamin D, calcium, potassium, and iron (2020–2025 Dietary Guidelines for Americans) |
| Fat-soluble vitamins | A, D, E, K |
| Water-soluble vitamins | C, B1, B2, B3, B5, B6, B7, B9, B12 |
Micronutrients fall into two main groups:
- Vitamins — organic compounds divided into fat-soluble (A, D, E, K) and water-soluble (C and the eight B vitamins).
- Minerals — inorganic elements such as calcium, iron, magnesium, zinc, and iodine.
For a broader foundation, our nutrition fundamentals overview covers how all these pieces fit together.
Key Vitamins and What They Do
Micronutrient
A vitamin or mineral the body needs in relatively small amounts — but cannot produce in sufficient quantities on its own — to support normal physiological functions.
Fat-soluble vitamin
Vitamins A, D, E, and K, which are absorbed alongside dietary fat and stored in the body's fatty tissues and liver. Because they accumulate, very high doses from supplements can cause toxicity.
Water-soluble vitamin
Vitamin C and the eight B vitamins, which dissolve in water and are not stored in large amounts. Excess is generally excreted in urine, so regular dietary intake is necessary.
Trace mineral
A mineral the body requires in very small amounts — such as iron, zinc, iodine, and selenium — but that is still essential for specific biochemical processes.
Bioavailability
The proportion of a nutrient that is actually absorbed and used by the body. Bioavailability varies by food form, preparation method, and individual digestive factors.
Daily Value (DV)
A reference amount set by the FDA used on Nutrition Facts labels to help consumers understand how much of a nutrient a serving of food contributes toward a general daily intake goal.
Below is a practical overview of the vitamins most commonly discussed in public health guidance, what each one does, and where to find it:
| Vitamin | Primary Role | Common Food Sources |
|---|---|---|
| A | Vision, immune function, skin and cell growth | Liver, dairy, eggs; beta-carotene in sweet potato, carrots, spinach |
| C | Antioxidant, collagen synthesis, immune support | Citrus fruits, bell peppers, broccoli, strawberries |
| D | Calcium absorption, bone health, immune modulation | Fatty fish, fortified dairy and plant milks, egg yolks; skin synthesis via sunlight |
| E | Antioxidant, cell membrane protection | Nuts, seeds, vegetable oils, wheat germ |
| K | Blood clotting, bone metabolism | Leafy greens (kale, spinach), fermented foods |
| B12 | Nerve function, red blood cell formation, DNA synthesis | Meat, fish, dairy, eggs; fortified foods for plant-based diets |
| Folate (B9) | DNA repair, cell division; critical during pregnancy | Legumes, leafy greens, fortified grains, citrus |
| B6 | Protein metabolism, neurotransmitter production | Poultry, fish, potatoes, bananas |
Essential Minerals at a Glance
42%
US adults with vitamin D insufficiency
Based on a large analysis of NHANES data published in Nutrients (2022), with higher rates among non-Hispanic Black and Hispanic adults.
~10 mg/day
Recommended iron intake for adult men
Per NIH Office of Dietary Supplements; recommended amounts differ by age, sex, and life stage — women of childbearing age need significantly more.
1 in 6
US adults with inadequate magnesium intake
Estimated from NHANES dietary intake data, as reported in public health nutrition literature.
Minerals are split into two tiers based on how much the body needs:
- Macrominerals (needed in larger amounts): calcium, phosphorus, magnesium, sodium, potassium, chloride, and sulfur.
- Trace minerals (needed in smaller amounts): iron, zinc, iodine, selenium, copper, manganese, and fluoride.
A few especially important ones to know:
- Calcium — the primary structural mineral in bones and teeth; also essential for muscle contraction and nerve transmission. Found in dairy, fortified plant milks, tofu, and leafy greens.
- Iron — carries oxygen in red blood cells. Heme iron (meat, poultry, seafood) is more readily absorbed than non-heme iron (legumes, fortified cereals, spinach).
- Magnesium — involved in more than 300 enzymatic reactions, including energy production and muscle relaxation. Rich sources include nuts, seeds, whole grains, and dark chocolate.
- Zinc — supports immune defense, wound healing, and taste and smell. Found in oysters, red meat, poultry, beans, and pumpkin seeds.
- Iodine — essential for thyroid hormone production. Iodized salt and seafood are the primary US sources.
Food First — and When to Consider Supplements
Nutrition science consistently shows that whole foods deliver micronutrients in complex matrices — alongside fiber, phytochemicals, and other compounds — that may enhance absorption and offer benefits beyond isolated nutrients. Our in-depth look at nutrition from food vs. supplements explores this evidence in detail.
More Isn't Always Better
Taking high-dose supplements without confirmed deficiency can cause harm. Fat-soluble vitamins in particular accumulate in the body, and excessive intake of vitamins A or D, for example, is associated with toxicity. Always discuss supplementation with a healthcare professional before starting, especially if you take prescription medications.
That said, certain populations have documented needs that diet alone may struggle to meet:
- People following strict plant-based diets may need B12 and may benefit from attention to iron, zinc, and iodine.
- Adults over 65 often have reduced absorption of B12 and vitamin D.
- People with limited sun exposure may need supplemental vitamin D.
- During pregnancy, folate needs increase substantially.
Understanding the numbers on packaged food can also help. Our guide to reading a Nutrition Facts label explains how Daily Values are calculated and what they mean in practice.
This article is for general informational and educational purposes only and is not a substitute for professional medical or dietary advice. Consult a qualified healthcare provider or registered dietitian before making significant changes to your diet or starting any supplement regimen.