| Total essential vitamins | 13 (National Institutes of Health, Office of Dietary Supplements) |
| Fat-soluble vitamins | A, D, E, K |
| Most common global deficiency | Iron deficiency (World Health Organization) |
| Nutrient most linked to limited sun exposure | Vitamin D |
| Mineral involved in 300+ enzymatic reactions | Magnesium (National Institutes of Health, Office of Dietary Supplements) |
| Folate importance flag | Critical during pregnancy for fetal development (CDC) |
Why Vitamins and Minerals Matter
Vitamins and minerals — collectively called micronutrients — are compounds your body needs in relatively small amounts to function properly. Unlike the three macronutrients (protein, carbohydrates, and fat), micronutrients don't supply calories. Instead, they act as essential helpers in virtually every biological process: energy production, immune defense, bone maintenance, nerve signaling, and more. See our guide to macronutrients for context on how these two categories work together.
Most people can meet their micronutrient needs through a varied, whole-food diet. However, certain life stages, health conditions, or eating patterns can create gaps. This reference is designed as a plain-language lookup — not a supplement prescription — to help you understand what each key nutrient does and where to find it in food.
This article is for general educational purposes only and is not a substitute for personalized medical or dietary advice. Consult a qualified healthcare professional before making significant changes to your diet or starting any supplement.
| Total essential vitamins | 13 (National Institutes of Health, Office of Dietary Supplements) |
| Fat-soluble vitamins | A, D, E, K |
| Most common global deficiency | Iron deficiency (World Health Organization) |
| Nutrient most linked to limited sun exposure | Vitamin D |
| Mineral involved in 300+ enzymatic reactions | Magnesium (National Institutes of Health, Office of Dietary Supplements) |
| Folate importance flag | Critical during pregnancy for fetal development (CDC) |
Fat-Soluble Vitamins: A, D, E, and K
Fat-soluble vitamins are stored in the body's fatty tissue and liver, meaning they accumulate over time. This makes both deficiency and excess possible — another reason why food-first approaches are generally safer than high-dose supplementation without professional guidance.
- Vitamin A — Supports vision (especially in low light), immune function, and skin integrity. Found in liver, dairy, eggs, and as beta-carotene in orange and leafy green vegetables.
- Vitamin D — Critical for calcium absorption and bone health; also plays roles in immune regulation. Synthesized in skin exposed to sunlight; found in fatty fish, fortified dairy, and eggs. Deficiency is common, especially in northern latitudes and among people with limited sun exposure.
- Vitamin E — Acts as an antioxidant, protecting cell membranes from damage. Found in nuts, seeds, vegetable oils, and leafy greens.
- Vitamin K — Essential for blood clotting and bone metabolism. Vitamin K1 comes primarily from leafy greens; K2 is found in fermented foods and some animal products.
Micronutrient
Vitamins and minerals needed by the body in small amounts to support normal biological functions. Unlike macronutrients, they provide no calories.
Fat-soluble vitamin
Vitamins (A, D, E, K) that dissolve in fat and are stored in the body's tissues. Because they accumulate, excessive intake over time can be harmful.
Water-soluble vitamin
Vitamins (C and the B vitamins) that dissolve in water and are not stored in large amounts. The body excretes excess through urine, making regular intake important.
Heme iron
A form of iron found in animal products such as meat and fish that is absorbed more efficiently by the body than non-heme iron from plant sources.
Non-heme iron
Iron found in plant-based foods like legumes and leafy greens. Its absorption can be improved by consuming it alongside vitamin C-rich foods.
Bioavailability
The proportion of a nutrient that the body actually absorbs and can use. Factors like food preparation, other foods consumed at the same time, and individual health affect bioavailability.
Recommended Dietary Allowance (RDA)
The average daily intake level sufficient to meet the nutrient requirements of nearly all healthy individuals in a specific life-stage group, as established by health authorities.
Water-Soluble Vitamins: B Complex and Vitamin C
Water-soluble vitamins are not stored in large amounts, so regular dietary intake matters more. The body excretes most excesses in urine, which lowers (but doesn't eliminate) the risk of toxicity from food sources.
- Vitamin C — Supports immune function, collagen synthesis, and iron absorption from plant foods. Found in citrus fruit, bell peppers, strawberries, and broccoli.
- B1 (Thiamine) — Helps convert food into energy. Found in whole grains, legumes, and pork.
- B2 (Riboflavin) — Important for energy metabolism and cellular function. Found in dairy, eggs, lean meats, and leafy greens.
- B3 (Niacin) — Involved in DNA repair and energy production. Found in poultry, fish, peanuts, and fortified grains.
- B6 — Key for protein metabolism and neurotransmitter production. Found in poultry, fish, potatoes, and bananas.
- B9 (Folate) — Critical for DNA synthesis and cell division; especially important during pregnancy. Found in legumes, leafy greens, and fortified foods.
- B12 — Required for nerve function and red blood cell formation. Found almost exclusively in animal products; supplementation is often recommended for those following a vegan diet.
Key Minerals: Calcium, Iron, Magnesium, and Zinc
Minerals are inorganic elements that the body cannot produce on its own. The following four are among the most clinically relevant for everyday American eaters.
~42%
U.S. adults with vitamin D insufficiency
According to analysis published in Nutrition Research using NHANES data, a substantial share of American adults have blood levels below the sufficiency threshold.
#1
Most widespread nutritional deficiency worldwide
The World Health Organization identifies iron deficiency as the most common nutritional disorder globally, affecting billions of people.
~48%
Americans not meeting magnesium recommendations
Data from national dietary surveys suggest nearly half of U.S. adults consume less magnesium than recommended daily amounts.
- Calcium — The most abundant mineral in the body, vital for bone and tooth structure, muscle contraction, and nerve transmission. Found in dairy products, fortified plant milks, tofu made with calcium sulfate, and leafy greens like kale and bok choy.
- Iron — Carries oxygen in red blood cells. Heme iron from red meat and poultry is absorbed more readily than non-heme iron from plant sources. Consuming vitamin C alongside plant-based iron improves absorption. Deficiency — the most common micronutrient deficiency worldwide — causes fatigue and anemia.
- Magnesium — Involved in over 300 enzymatic reactions, including energy production, muscle function, and blood sugar regulation. Found in nuts, seeds, whole grains, and dark leafy greens. Many adults consume less than recommended amounts.
- Zinc — Supports immune function, wound healing, and taste and smell perception. Found in oysters, red meat, poultry, beans, and fortified cereals.
For practical guidance on building meals rich in these nutrients, see our guide to building a balanced plate. If cost is a consideration, our eating well on a budget article offers strategies for sourcing nutrient-dense foods affordably, and the weekly grocery checklist can help you stock a well-rounded pantry.