| Total essential vitamins | 13 (NIH Office of Dietary Supplements) |
| Fat-soluble vitamins | A, D, E, K (NIH Office of Dietary Supplements) |
| Water-soluble vitamins | C and 8 B vitamins (NIH Office of Dietary Supplements) |
| Most common US deficiencies | Vitamin D, calcium, potassium, iron (Dietary Guidelines for Americans 2020–2025) |
| % DV threshold for "high" source | 20% or more per serving (FDA Nutrition Facts label guidance) |
What Are Micronutrients and Why Do They Matter?
Micronutrients are vitamins and minerals that the body requires in relatively small amounts but cannot manufacture in sufficient quantities on its own. Unlike macronutrients — carbohydrates, proteins, and fats — they provide no direct energy, yet they are indispensable for virtually every physiological process: immune defense, bone formation, nerve signaling, energy metabolism, and DNA repair. To understand how micronutrients fit alongside the bigger picture of what you eat, see our guide to macronutrients.
Vitamins are organic compounds divided into two categories based on how they are stored. Fat-soluble vitamins (A, D, E, K) accumulate in body fat and the liver, meaning both deficiency and excess can occur over time. Water-soluble vitamins (C and the eight B vitamins) are not stored in large amounts; the body excretes surpluses in urine, so regular dietary intake is important.
Minerals are inorganic elements sourced from soil and water and absorbed through food. Macrominerals — such as calcium, magnesium, and potassium — are needed in larger quantities. Trace minerals — including iron, zinc, iodine, and selenium — are needed in smaller amounts but remain equally essential.
Micronutrient
Vitamins and minerals required by the body in small amounts to support essential physiological functions. Unlike macronutrients, they do not provide energy (calories).
Fat-soluble vitamin
Vitamins (A, D, E, K) that dissolve in fat and are stored in body tissues. Because they accumulate, both deficiency and toxicity from excess intake are possible.
Water-soluble vitamin
Vitamins (C and the B vitamins) that dissolve in water and are not stored in large amounts. Excess is generally excreted in urine, making regular dietary intake important.
Trace mineral
A mineral required in very small quantities — typically less than 100 milligrams per day — but still essential for health. Examples include iron, zinc, iodine, and selenium.
Daily Value (DV)
A reference amount set by the FDA used on US Nutrition Facts labels to indicate how much of a nutrient a food serving contributes toward general daily intake recommendations.
Bioavailability
The proportion of a nutrient that the body actually absorbs and uses after ingestion. It varies depending on the food source, preparation method, and individual health factors.
Essential Vitamins: Functions and Food Sources
The table below summarizes key vitamins recognized by the National Institutes of Health (NIH) Office of Dietary Supplements, along with their primary roles and reliable dietary sources.
| Total essential vitamins | 13 (NIH Office of Dietary Supplements) |
| Fat-soluble vitamins | A, D, E, K (NIH Office of Dietary Supplements) |
| Water-soluble vitamins | C and 8 B vitamins (NIH Office of Dietary Supplements) |
| Most common US deficiencies | Vitamin D, calcium, potassium, iron (Dietary Guidelines for Americans 2020–2025) |
| % DV threshold for "high" source | 20% or more per serving (FDA Nutrition Facts label guidance) |
| Vitamin | Primary Function | Common Food Sources |
|---|---|---|
| A | Vision, immune function, cell growth | Liver, dairy, eggs, orange and yellow vegetables |
| D | Calcium absorption, bone health, immune modulation | Fatty fish, fortified milk, egg yolks, sunlight exposure |
| E | Antioxidant protection, immune support | Nuts, seeds, vegetable oils, leafy greens |
| K | Blood clotting, bone metabolism | Leafy greens, fermented foods, some vegetable oils |
| C | Collagen synthesis, antioxidant, iron absorption | Citrus fruits, bell peppers, strawberries, broccoli |
| B1 (Thiamine) | Energy metabolism, nerve function | Whole grains, pork, legumes, nuts |
| B2 (Riboflavin) | Energy production, cellular growth | Dairy, lean meats, eggs, leafy vegetables |
| B3 (Niacin) | DNA repair, energy metabolism | Poultry, fish, peanuts, enriched grains |
| B6 | Protein metabolism, neurotransmitter synthesis | Poultry, fish, potatoes, bananas |
| B9 (Folate) | DNA synthesis, cell division, fetal development | Legumes, leafy greens, fortified cereals, oranges |
| B12 | Nerve function, red blood cell formation | Meat, fish, dairy, eggs, fortified plant milks |
Sources: NIH Office of Dietary Supplements; USDA FoodData Central.
Note for special populations: Folate needs increase significantly during pregnancy. People following plant-based diets should pay particular attention to vitamin B12 and vitamin D intake. Consult a healthcare provider about your individual needs.
Key Minerals: Functions and Food Sources
Minerals work alongside vitamins in many metabolic pathways. Getting adequate amounts from a varied diet reduces the risk of deficiency without the excess risk that can come with high-dose supplements.
| Mineral | Primary Function | Common Food Sources |
|---|---|---|
| Calcium | Bone and tooth structure, muscle contraction, nerve transmission | Dairy, fortified plant milks, leafy greens, tofu |
| Magnesium | Enzyme reactions, muscle and nerve function, blood sugar regulation | Nuts, seeds, whole grains, leafy greens, legumes |
| Potassium | Fluid balance, blood pressure regulation, nerve function | Bananas, potatoes, beans, dairy, leafy greens |
| Iron | Oxygen transport in red blood cells, energy metabolism | Red meat, poultry, beans, lentils, fortified cereals |
| Zinc | Immune function, wound healing, protein synthesis | Oysters, beef, pumpkin seeds, chickpeas, dairy |
| Iodine | Thyroid hormone production, metabolism regulation | Iodized salt, seafood, dairy, seaweed |
| Selenium | Antioxidant defense, thyroid function | Brazil nuts, seafood, poultry, eggs, whole grains |
Sources: NIH Office of Dietary Supplements; Dietary Guidelines for Americans 2020–2025.
~42%
US adults with vitamin D insufficiency
According to analysis published in Nutrition Research using NHANES data, approximately 42% of US adults have insufficient vitamin D levels.
~10%
US women of childbearing age with iron deficiency
The CDC estimates that roughly 10% of US women of childbearing age are iron deficient, making it one of the most common nutrient deficiencies in this group.
4 nutrients
Nutrients of public health concern in the US
The Dietary Guidelines for Americans 2020–2025 identify vitamin D, calcium, potassium, and iron as nutrients most commonly under-consumed by US adults.
The balanced plate model provides a practical way to structure meals that naturally cover many of these mineral needs without tracking every gram.
Practical Takeaways and When to Seek Guidance
For most healthy US adults, a diet emphasizing vegetables, fruits, whole grains, lean proteins, and dairy or fortified alternatives will supply adequate amounts of the vitamins and minerals listed here. Variety is the single most reliable strategy — no single food covers every micronutrient.
Certain groups face higher deficiency risk and may benefit from professional evaluation: older adults (vitamin D, B12), people who are pregnant or planning pregnancy (folate, iron), those following strict plant-based diets (B12, iron, zinc, iodine), and individuals with conditions that impair nutrient absorption. Micronutrient needs also shift across the lifespan; see how dietary needs change with age for more context.
Reading food labels is a practical everyday tool. The % Daily Value (% DV) column on a Nutrition Facts label reflects how much of each listed nutrient a serving contributes toward general reference intakes. The nutrition label guide explains how to interpret these figures accurately.
Supplements can help address confirmed deficiencies or meet needs that diet alone cannot reliably cover, but they are not a substitute for a varied diet and carry risks at high doses. Any decision to use supplements — particularly fat-soluble vitamins and minerals with narrow safe ranges — should involve a qualified healthcare provider.
Supplements Are Not a Replacement for Diet
While supplements can help address documented deficiencies, the NIH and major dietary guidelines emphasize that whole foods provide complex combinations of nutrients, fiber, and phytochemicals that supplements cannot fully replicate. High-dose supplementation of fat-soluble vitamins and some minerals can cause adverse effects. Always discuss supplement use with a healthcare provider who can evaluate your specific situation.
For structured meal planning that accounts for micronutrient variety, the weekly meal planning checklist is a useful starting point.
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 before making significant changes to your diet or starting any supplement regimen.