| Total essential vitamins | 13 (NIH Office of Dietary Supplements) |
| Vitamins classified as water-soluble | 9 (vitamin C + 8 B vitamins) (NIH Office of Dietary Supplements) |
| Vitamins classified as fat-soluble | 4 (A, D, E, K) (NIH Office of Dietary Supplements) |
| Essential minerals recognized | 16 (macro- and trace minerals combined) (Dietary Reference Intakes, National Academies) |
| Most common micronutrient deficiency globally | Iron deficiency (World Health Organization) |
| Vitamin D: primary natural source | Skin synthesis via sunlight (UVB radiation) (NIH Office of Dietary Supplements) |
What Micronutrients Are — and Why They Matter
Micronutrients is the collective term for vitamins and minerals — the compounds your body needs in relatively small amounts to function normally. Unlike macronutrients (carbohydrates, protein, and fat), micronutrients don't supply calories. What they do instead is far more varied: they regulate metabolism, support immune function, enable nerve signaling, help build bone, and assist in thousands of enzymatic reactions throughout the body.
The key distinction is that the human body cannot synthesize most micronutrients on its own, or cannot make them in sufficient quantities. That makes dietary intake — and sometimes supplementation under medical guidance — the primary way people maintain adequate levels. For a broader overview of where micronutrients fit in the nutritional picture, see our overview of essential vitamins and minerals.
Micronutrient
A vitamin or mineral required by the body in small amounts to support normal physiological function. Micronutrients do not provide calories but are essential for metabolism, growth, and health.
Water-Soluble Vitamin
A vitamin that dissolves in water and is not stored significantly in the body. Excess amounts are generally excreted in urine, making consistent dietary intake important. Examples include vitamin C and the B vitamins.
Fat-Soluble Vitamin
A vitamin that dissolves in fat and can be stored in the body's fatty tissue and liver. Vitamins A, D, E, and K are fat-soluble; because they accumulate, excessive supplementation warrants caution.
Trace Mineral
A mineral the body needs in very small (trace) quantities — typically less than 100 milligrams per day. Despite the tiny amounts required, trace minerals like iron, zinc, and selenium are essential for critical body functions.
Bioavailability
The proportion of a nutrient that the body is actually able to absorb and use after consumption. Bioavailability varies by food form, preparation method, and other nutrients consumed at the same time.
Fortified Food
A food product to which one or more nutrients have been added that were not originally present, or were present in smaller amounts, to improve its nutritional value. Common examples include iodized salt and vitamin D–fortified milk.
Vitamins: Water-Soluble vs. Fat-Soluble
Vitamins fall into two categories based on how the body stores and transports them, and this distinction matters for understanding both food sources and excess intake.
Water-Soluble Vitamins
The B vitamins (B1/thiamine, B2/riboflavin, B3/niacin, B5/pantothenic acid, B6, B7/biotin, B9/folate, and B12) and vitamin C dissolve in water. Because the body excretes excess amounts in urine rather than storing them, regular dietary intake is important. Good food sources include:
- Vitamin C: Citrus fruits, bell peppers, broccoli, strawberries
- Folate (B9): Dark leafy greens, legumes, fortified grains
- B12: Animal products (meat, fish, dairy, eggs); fortified plant-based foods for those on vegan diets
- B6: Poultry, fish, potatoes, bananas, chickpeas
Fat-Soluble Vitamins
Vitamins A, D, E, and K are absorbed alongside dietary fat and stored in body fat and the liver. Because they accumulate, very high supplemental doses can potentially cause problems — which is why these vitamins warrant particular attention when considering supplements. Common food sources include:
- Vitamin A: Liver, dairy, eggs; beta-carotene (a precursor) from orange and yellow vegetables
- Vitamin D: Fatty fish, egg yolks, fortified milk; synthesized in skin via sunlight
- Vitamin E: Nuts, seeds, vegetable oils, leafy greens
- Vitamin K: Leafy greens (K1); fermented foods, some animal products (K2)
| Total essential vitamins | 13 (NIH Office of Dietary Supplements) |
| Vitamins classified as water-soluble | 9 (vitamin C + 8 B vitamins) (NIH Office of Dietary Supplements) |
| Vitamins classified as fat-soluble | 4 (A, D, E, K) (NIH Office of Dietary Supplements) |
| Essential minerals recognized | 16 (macro- and trace minerals combined) (Dietary Reference Intakes, National Academies) |
| Most common micronutrient deficiency globally | Iron deficiency (World Health Organization) |
| Vitamin D: primary natural source | Skin synthesis via sunlight (UVB radiation) (NIH Office of Dietary Supplements) |
Key Minerals at a Glance
Minerals are inorganic elements that the body uses for structural and regulatory purposes. They're broadly divided into macrominerals (needed in larger amounts) and trace minerals (needed in smaller quantities but no less essential).
Macrominerals
- Calcium: Bone and tooth structure, muscle contraction, nerve transmission — dairy products, fortified plant milks, leafy greens, tofu made with calcium sulfate
- Magnesium: Involved in over 300 enzyme reactions, muscle and nerve function — nuts, seeds, whole grains, dark chocolate, legumes
- Potassium: Fluid balance, blood pressure regulation, heart rhythm — bananas, potatoes, beans, tomatoes, yogurt
- Phosphorus: Bone formation, energy production — widely found in protein-rich foods like meat, fish, dairy, and legumes
Trace Minerals
- Iron: Oxygen transport in red blood cells — red meat, poultry, beans, lentils, fortified cereals; vitamin C can enhance absorption of plant-based iron
- Zinc: Immune function, wound healing, DNA synthesis — meat, shellfish, legumes, seeds, dairy
- Iodine: Thyroid hormone production — iodized salt, seafood, dairy
- Selenium: Antioxidant defense, thyroid function — Brazil nuts, fish, poultry, eggs
Understanding how these nutrients appear on product labels is made easier with tools like a line-by-line guide to the Nutrition Facts label, which explains percent daily values in plain terms.
Putting It Into Practice
No single food provides every micronutrient in useful quantities, which is why variety remains the most practical guiding principle in nutrition guidance. Eating a wide range of whole foods — vegetables, fruits, whole grains, legumes, nuts, seeds, and proteins from diverse sources — naturally covers most micronutrient needs for most healthy adults.
Certain groups may have higher needs or absorption challenges: older adults, people who are pregnant or breastfeeding, those with specific medical conditions, and individuals following highly restricted diets. In these cases, individual supplementation needs should be discussed with a qualified healthcare provider, not inferred from general reference guides like this one.
For practical context on how micronutrients relate to the broader landscape of what you eat, the Nutrition Basics hub offers foundational articles covering everything from macronutrients to label reading. You can also explore key nutrition terms to navigate food labels and health articles with greater confidence.
This article is for general educational purposes only and is not a substitute for personalized medical or dietary advice. Consult a registered dietitian or qualified healthcare professional before making significant changes to your diet or starting any supplement regimen.