| Vitamins classified as fat-soluble | A, D, E, K (National Institutes of Health, Office of Dietary Supplements) |
| Water-soluble vitamins | Vitamin C + 8 B vitamins (NIH Office of Dietary Supplements) |
| Most common micronutrient deficiency globally | Iron deficiency (World Health Organization) |
| Vitamin D deficiency prevalence (US adults) | Estimated 1 in 4 adults (CDC National Health and Nutrition Examination Survey) |
| B12 concern for plant-based diets | Found almost exclusively in animal products (Harvard T.H. Chan School of Public Health) |
| Minerals categorized as major minerals | Calcium, magnesium, potassium, sodium, phosphorus, chloride, sulfur (NIH Office of Dietary Supplements) |
Why Micronutrients Matter
Macronutrients — carbohydrates, protein, and fat — get most of the nutrition spotlight, but micronutrients (vitamins and minerals) do the foundational work that keeps nearly every body system running. They activate enzymes, support immune defense, maintain bone density, regulate nerve signals, and enable cells to produce energy. Unlike macronutrients, the body needs them in relatively small amounts, but consistent shortfalls have measurable consequences over time.
Most adults can meet their micronutrient needs through a varied, whole-food diet without tracking every number. The goal of this reference is simple: give you a working understanding of the key players, what they do, and where to find them — so you can make more confident food choices day to day. For a deeper look at how these nutrients appear on food packaging, see reading a nutrition facts label.
| Vitamins classified as fat-soluble | A, D, E, K (National Institutes of Health, Office of Dietary Supplements) |
| Water-soluble vitamins | Vitamin C + 8 B vitamins (NIH Office of Dietary Supplements) |
| Most common micronutrient deficiency globally | Iron deficiency (World Health Organization) |
| Vitamin D deficiency prevalence (US adults) | Estimated 1 in 4 adults (CDC National Health and Nutrition Examination Survey) |
| B12 concern for plant-based diets | Found almost exclusively in animal products (Harvard T.H. Chan School of Public Health) |
| Minerals categorized as major minerals | Calcium, magnesium, potassium, sodium, phosphorus, chloride, sulfur (NIH Office of Dietary Supplements) |
Key Vitamins Adults Should Know
Vitamins fall into two categories based on how the body stores them:
- Fat-soluble vitamins (A, D, E, K) are stored in body fat and the liver. Because they accumulate, excessive supplementation can reach harmful levels — context worth keeping in mind.
- Water-soluble vitamins (C and the eight B vitamins) are not stored in large amounts; excess is excreted in urine, so regular dietary intake matters more.
Fat-Soluble Vitamins
- Vitamin A
- Supports vision (especially in low light), immune function, and skin cell turnover. Found in liver, dairy, eggs, and as beta-carotene in orange and dark-green vegetables like sweet potato, carrots, and spinach.
- Vitamin D
- Essential for calcium absorption and bone health; also plays a role in immune regulation. Synthesized through sun exposure; dietary sources include fatty fish, egg yolks, and fortified foods. Deficiency is common in northern climates and among people with limited sun exposure.
- Vitamin E
- Acts as an antioxidant, protecting cell membranes. Found in nuts, seeds, vegetable oils, and leafy greens.
- Vitamin K
- Critical for blood clotting and bone metabolism. Found in leafy greens (kale, spinach, broccoli) and fermented foods.
Water-Soluble Vitamins
- Vitamin C
- Supports collagen synthesis, wound healing, and immune function; also aids iron absorption from plant sources. Citrus, bell peppers, strawberries, and broccoli are excellent sources.
- B Vitamins (B1, B2, B3, B5, B6, B7, B9, B12)
- This family drives energy metabolism, red blood cell production, and neurological function. Folate (B9) is especially critical during early pregnancy. B12 is found almost exclusively in animal products, making it a key consideration for people following plant-based diets.
Micronutrient
Vitamins and minerals required by the body in small amounts to support growth, metabolism, and overall health. Unlike macronutrients, they provide no direct energy (calories).
Fat-soluble vitamin
Vitamins (A, D, E, K) that dissolve in fat and are stored in the body's fatty tissues and liver. Because they accumulate, very high intake — especially from supplements — can reach toxic levels.
Water-soluble vitamin
Vitamins (C and the B vitamins) that dissolve in water and are not stored in significant amounts. Excess is generally excreted in urine, so consistent daily intake through food is important.
Trace mineral
A mineral the body needs in very small quantities — typically less than 100 mg per day. Examples include iron, zinc, iodine, and selenium. Small amounts does not mean less essential.
Heme iron
A form of dietary iron found in animal-based foods such as red meat, poultry, and fish. It is absorbed by the body more efficiently than non-heme iron from plant sources.
Recommended Dietary Allowance (RDA)
The average daily intake level sufficient to meet the nutrient requirements of nearly all healthy individuals in a given life stage, as established by the National Academies of Sciences, Engineering, and Medicine.
Essential Minerals and Where to Find Them
Minerals are inorganic elements the body cannot make itself. They're divided into major minerals (needed in larger amounts) and trace minerals (needed in smaller amounts — but no less important).
~45%
US adults with inadequate magnesium intake
According to NHANES data analyzed by nutrition researchers, nearly half of US adults fall short of the Estimated Average Requirement for magnesium.
300+
Enzymatic reactions requiring magnesium
The NIH Office of Dietary Supplements notes magnesium is a cofactor in more than 300 enzyme systems throughout the body.
2 billion
People affected by iron deficiency worldwide
The World Health Organization identifies iron deficiency as the most prevalent nutritional disorder globally.
Major Minerals
- Calcium: Bone and tooth structure, muscle contraction, nerve signaling. Sources: dairy, fortified plant milks, tofu made with calcium sulfate, sardines, kale.
- Magnesium: Involved in over 300 enzymatic reactions, including blood sugar regulation and muscle function. Sources: legumes, whole grains, nuts, seeds, dark chocolate.
- Potassium: Maintains fluid balance and healthy blood pressure. Sources: bananas, potatoes, beans, leafy greens, avocado.
- Sodium: Essential for fluid balance and nerve function — though most US adults consume well above recommended levels through processed foods.
- Phosphorus: Works alongside calcium in bone structure and energy metabolism. Found widely in protein-rich foods.
Trace Minerals
- Iron: Carries oxygen in red blood cells. Heme iron (from meat) absorbs more readily than non-heme iron (from plants). Pairing plant iron sources with vitamin C improves absorption.
- Zinc: Immune function, wound healing, and DNA synthesis. Sources: meat, shellfish, legumes, pumpkin seeds.
- Iodine: Needed for thyroid hormone production. Iodized salt and seafood are primary sources.
- Selenium: Antioxidant function and thyroid health. Brazil nuts are an unusually concentrated source.
Building a plate around diverse whole foods — vegetables, legumes, whole grains, lean proteins, and healthy fats — naturally covers most of these bases. See the building blocks of a balanced plate for a practical framework.
This article is for general informational and educational purposes only and is not a substitute for professional medical or nutritional advice. Consult a qualified healthcare provider before making significant changes to your diet or starting any supplement regimen.