Micronutrients at a Glance: Vitamins and Minerals Every Adult Should Know
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In this article
A concise reference covering key vitamins and minerals, their roles in the body, and common food sources for each.
What Are Micronutrients and Why Do They Matter?
Micronutrients are the vitamins and minerals your body needs in relatively small amounts to function correctly. Unlike macronutrients — carbohydrates, protein, and fat — they provide no calories, but they are essential to nearly every biological process, from energy production and immune defense to bone maintenance and nerve signaling. If you are just starting to think about what you eat, our guide to nutrition fundamentals provides a helpful starting point.
Vitamins are organic compounds grouped into two categories: fat-soluble (A, D, E, K), which are stored in body tissue, and water-soluble (C and the B vitamins), which must be replenished more regularly because excess amounts are excreted. Minerals are inorganic elements divided into macrominerals — needed in larger amounts (calcium, magnesium, phosphorus, potassium, sodium, chloride, sulfur) — and trace minerals (iron, zinc, iodine, selenium, copper, manganese, fluoride, chromium, molybdenum).
Most healthy adults can meet their micronutrient needs through a varied, whole-food diet. Supplementation may be appropriate for specific populations or deficiencies, but that decision should be made in consultation with a qualified healthcare professional.
Micronutrient
A vitamin or mineral required by the body in small quantities for normal physiological function. Unlike macronutrients, micronutrients provide no energy but are essential to health.
Fat-soluble vitamin
Vitamins A, D, E, and K dissolve in fat and are stored in the body's fatty tissue and liver. Because they accumulate, excessive intake from supplements can reach harmful levels.
Water-soluble vitamin
Vitamins C and the B-complex group dissolve in water and are not significantly stored. The body excretes excess amounts in urine, so regular dietary intake is important.
Trace mineral
A mineral the body requires in very small amounts — typically less than 100 mg per day. Examples include iron, zinc, selenium, and iodine. Small does not mean unimportant; deficiencies can have serious health consequences.
Recommended Dietary Allowance (RDA)
The average daily intake level sufficient to meet the nutrient requirements of nearly all healthy individuals in a particular life-stage and sex group, as established by nutrition authorities.
Bioavailability
The proportion of a nutrient that the body actually absorbs and uses from food or a supplement. Bioavailability varies by nutrient form, food matrix, and individual digestive health.
Key Vitamins: Functions and Food Sources
The table below summarizes the major vitamins, their primary roles in the body, and reliable dietary sources. This is general educational information — individual needs vary based on age, sex, health status, and other factors.
| Total essential vitamins | 13 recognized (4 fat-soluble, 9 water-soluble) (National Institutes of Health, Office of Dietary Supplements) |
| Total essential minerals | Approximately 16, including 7 macrominerals and 9+ trace minerals (Dietary Reference Intakes, National Academies) |
| Most common U.S. vitamin deficiency | Vitamin D — widespread insufficiency across all age groups (CDC National Health and Nutrition Examination Survey) |
| Most common mineral deficiency globally | Iron deficiency — leading cause of nutritional anemia worldwide (World Health Organization) |
| Populations at elevated risk | Pregnant women, older adults, strict vegans, people with malabsorption conditions (National Institutes of Health, Office of Dietary Supplements) |
| Vitamin | Primary Role | Common Food Sources |
|---|---|---|
| Vitamin A | Vision, immune function, skin and cell growth | Beef liver, sweet potato, carrots, spinach, dairy |
| Vitamin C | Collagen synthesis, antioxidant defense, immune support | Bell peppers, citrus fruit, strawberries, broccoli |
| Vitamin D | Calcium absorption, bone health, immune modulation | Fatty fish, fortified milk, egg yolks; sunlight exposure |
| Vitamin E | Antioxidant protection, immune function | Sunflower seeds, almonds, spinach, vegetable oils |
| Vitamin K | Blood clotting, bone metabolism | Kale, spinach, Brussels sprouts, fermented foods |
| Vitamin B12 | Red blood cell formation, neurological function, DNA synthesis | Meat, fish, dairy, eggs; fortified plant foods |
| Folate (B9) | DNA synthesis, cell division; critical in pregnancy | Lentils, leafy greens, beans, fortified grains |
| Vitamin B6 | Protein metabolism, neurotransmitter production | Chickpeas, salmon, poultry, bananas, potatoes |
| Thiamine (B1) | Carbohydrate metabolism, nerve function | Whole grains, pork, legumes, nuts |
People following plant-based diets should pay particular attention to vitamin B12, which is found almost exclusively in animal products. Those with limited sun exposure may also need to monitor their vitamin D status. For changes to supplementation or diet related to specific health conditions, always consult a healthcare provider.
Key Minerals: Functions and Food Sources
Minerals support structural roles — such as building bones and teeth — as well as functional ones, including regulating fluid balance, muscle contraction, and oxygen transport.
| Mineral | Primary Role | Common Food Sources |
|---|---|---|
| Calcium | Bone and tooth structure, muscle contraction, nerve signaling | Dairy, fortified plant milks, leafy greens, tofu |
| Iron | Oxygen transport in red blood cells, energy metabolism | Red meat, lentils, tofu, fortified cereals, spinach |
| Magnesium | Enzyme function, muscle and nerve activity, blood sugar regulation | Pumpkin seeds, almonds, black beans, whole grains |
| Potassium | Fluid balance, blood pressure regulation, heart rhythm | Bananas, potatoes, avocados, beans, leafy greens |
| Zinc | Immune function, wound healing, protein synthesis | Oysters, red meat, pumpkin seeds, chickpeas |
| Iodine | Thyroid hormone production, metabolism regulation | Iodized salt, seaweed, dairy, fish |
| Selenium | Antioxidant defense, thyroid function | Brazil nuts, tuna, eggs, sunflower seeds |
Absorption Can Vary Significantly
The amount of a mineral listed on a nutrition label does not always equal what your body absorbs. For example, iron from plant foods (non-heme iron) is absorbed less efficiently than iron from meat, though consuming it alongside vitamin C can improve uptake. Similarly, calcium absorption is influenced by vitamin D status. These interactions are one reason dietary variety matters — and why a healthcare provider or registered dietitian is best positioned to assess your individual needs.
Because nutritional needs shift across the lifespan, our article on nutrition through the life stages explains how micronutrient requirements evolve from childhood through older adulthood. For context on how macronutrients and micronutrients work together, see our overview of what carbs, proteins, and fats actually do.
This article is for general informational and educational purposes only. It is not a substitute for professional medical or dietary advice. Consult a qualified healthcare provider before making changes to your diet or supplement routine, especially if you have a medical condition or take medications.
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Health & Wellness Editorial Team
Health & Wellness Editorial Team is the collective byline for our editorial team and contributor network. Articles published under this byline or an editorial pen name are researched, written, and reviewed according to our editorial standards for clarity, consistency, and independence before publication.
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