| Total essential vitamins | 13 (National Institutes of Health, Office of Dietary Supplements) |
| Fat-soluble vitamins | A, D, E, K |
| Water-soluble vitamins | C plus 8 B vitamins |
| Most common deficiency in the U.S. | Vitamin D (National Health and Nutrition Examination Survey (NHANES) data) |
| Iron deficiency prevalence | Affects ~10 million Americans (CDC estimates) |
| Recommended dietary approach | Varied whole-food diet (Dietary Guidelines for Americans, 2020–2025) |
Why Vitamins and Minerals Matter
Vitamins and minerals are micronutrients — compounds your body needs in small amounts to function properly. Unlike protein, carbohydrates, and fat, micronutrients don't supply calories, but they drive nearly every biological process: converting food into energy, building bone, supporting immunity, and regulating the nervous system. See our guide to macronutrients for how vitamins and minerals interact with the larger fuel picture.
Vitamins fall into two categories:
- Fat-soluble (A, D, E, K): stored in body fat and the liver; excess can accumulate.
- Water-soluble (C and all B vitamins): not stored long-term; excess is generally excreted in urine.
Minerals are inorganic elements. Macrominerals (calcium, magnesium, potassium, sodium) are needed in larger amounts; trace minerals (iron, zinc, iodine, selenium) are required in much smaller quantities but are equally essential.
Micronutrient
Vitamins and minerals that the body needs in small amounts to carry out essential physiological functions. Unlike macronutrients, they supply no calories but are critical to health.
Fat-soluble vitamin
Vitamins A, D, E, and K, which dissolve in fat and are stored in body tissue. Because they accumulate, excessive intake — typically from high-dose supplements — can reach harmful levels.
Water-soluble vitamin
Vitamin C and the B vitamins, which dissolve in water and are not stored in significant quantities. The body excretes excess amounts in urine, though very high supplement doses can still cause problems.
Trace mineral
A mineral required by the body in very small amounts — such as iron, zinc, iodine, and selenium — that nonetheless plays essential roles in metabolism, immunity, and organ function.
Macromineral
Minerals needed in relatively larger amounts, including calcium, magnesium, potassium, and sodium, which support bone structure, fluid balance, and nerve and muscle function.
Bioavailability
The proportion of a nutrient that the body actually absorbs and uses after consumption. It varies based on the food form, preparation method, and individual factors such as gut health.
Key Vitamins: What They Do and Where to Find Them
The table below summarizes the most important vitamins, their primary roles, common food sources, and general signs associated with low intake. This is educational context — it is not a diagnostic tool. Always consult a qualified healthcare professional if you suspect a deficiency.
| Total essential vitamins | 13 (National Institutes of Health, Office of Dietary Supplements) |
| Fat-soluble vitamins | A, D, E, K |
| Water-soluble vitamins | C plus 8 B vitamins |
| Most common deficiency in the U.S. | Vitamin D (National Health and Nutrition Examination Survey (NHANES) data) |
| Iron deficiency prevalence | Affects ~10 million Americans (CDC estimates) |
| Recommended dietary approach | Varied whole-food diet (Dietary Guidelines for Americans, 2020–2025) |
| Vitamin | Primary Role | Common Food Sources | General Signs of Low Intake |
|---|---|---|---|
| A | Vision, immune function, cell growth | Sweet potato, carrots, liver, dairy | Night blindness, dry skin |
| C | Antioxidant, collagen synthesis, immune support | Citrus, bell peppers, strawberries, broccoli | Fatigue, slow wound healing |
| D | Calcium absorption, bone health, immune modulation | Fatty fish, fortified milk, egg yolks, sunlight | Bone pain, muscle weakness |
| E | Antioxidant, immune support | Sunflower seeds, almonds, vegetable oils, spinach | Nerve and muscle problems (rare) |
| K | Blood clotting, bone metabolism | Kale, spinach, broccoli, fermented foods | Easy bruising, slow clotting |
| B12 | Nerve function, red blood cell formation | Meat, fish, dairy, fortified cereals | Fatigue, numbness, cognitive changes |
| Folate (B9) | DNA synthesis, cell division | Legumes, leafy greens, fortified grains, citrus | Fatigue, megaloblastic anemia |
| B6 | Protein metabolism, neurotransmitter production | Poultry, fish, potatoes, bananas | Irritability, cracked lips, confusion |
Key Minerals: What They Do and Where to Find Them
| Mineral | Primary Role | Common Food Sources | General Signs of Low Intake |
|---|---|---|---|
| Calcium | Bone and teeth structure, muscle contraction, nerve signaling | Dairy, fortified plant milks, tofu, sardines | Muscle cramps, weakened bones over time |
| Iron | Oxygen transport in red blood cells | Red meat, lentils, spinach, fortified cereals | Fatigue, pallor, difficulty concentrating |
| Magnesium | Energy production, muscle and nerve function, blood sugar regulation | Nuts, seeds, whole grains, leafy greens | Muscle cramps, sleep disturbances |
| Potassium | Fluid balance, heart rhythm, muscle function | Bananas, potatoes, beans, yogurt | Muscle weakness, irregular heartbeat |
| Zinc | Immune function, wound healing, taste and smell | Oysters, beef, pumpkin seeds, legumes | Frequent illness, slow healing, altered taste |
| Iodine | Thyroid hormone production | Iodized salt, seafood, dairy | Thyroid enlargement, fatigue — see thyroid conditions overview |
| Selenium | Antioxidant defense, thyroid function | Brazil nuts, tuna, eggs, sunflower seeds | Muscle weakness, immune impairment |
A Note on Supplements vs. Food Sources
While supplements can address documented deficiencies, whole foods deliver nutrients alongside fiber, phytonutrients, and other compounds that work together in ways supplements cannot fully replicate. High-dose supplementation of certain nutrients — particularly fat-soluble vitamins and some minerals — can be harmful. Any decision about supplementation should involve a healthcare provider who can assess your actual needs.
Putting It Into Practice
No single food delivers every micronutrient, which is why dietary variety is consistently emphasized by nutrition researchers. A practical approach: fill half your plate with vegetables and fruit across a range of colors, include a quality protein source at most meals, and choose whole grains over refined ones when possible. For a structured approach to building that plate at the store, see our guide to grocery shopping with nutrition in mind.
Keep in mind that nutrient needs shift across life stages — the iron needs of a woman in her 30s differ from those of a person in their 60s. Our article on nutrition through every decade walks through those changes in detail. And when you're evaluating packaged foods for micronutrient content, knowing how to read an ingredient list can help you make more informed choices.
Supplements can fill genuine gaps in some populations, but they are not a substitute for a balanced diet, and some nutrients carry real risks at high doses. Speak with a healthcare provider before starting any supplement regimen — especially if you have a chronic health condition, are pregnant, or are caring for a child.
This article is for general informational and educational purposes only and does not constitute medical advice. Consult a qualified healthcare professional for guidance specific to your health situation.