| Total essential vitamins | 13 (4 fat-soluble, 9 water-soluble) (National Institutes of Health, Office of Dietary Supplements) |
| Total essential minerals | At least 16 recognized as essential for humans (Dietary Reference Intakes, National Academies) |
| Most common U.S. deficiency | Vitamin D, followed by iron and calcium (CDC Second National Report on Biochemical Indicators of Diet and Nutrition) |
| Vitamin D sources | Sun exposure, fatty fish, fortified dairy and plant milks |
| Groups at higher deficiency risk | Older adults, pregnant individuals, vegans/vegetarians, people with limited sun exposure (National Institutes of Health, Office of Dietary Supplements) |
| Best overall strategy | Varied whole-food diet across food groups (2020–2025 Dietary Guidelines for Americans) |
What Are Micronutrients and Why Do They Matter?
Micronutrients are the vitamins and minerals your body needs in relatively small amounts — but their impact on health is anything but small. Unlike macronutrients like carbs, protein, and fat, which provide energy, micronutrients drive the chemical processes that keep every system in your body working: immune defense, bone formation, nerve signaling, and energy metabolism.
Most Americans can meet their micronutrient needs through a varied, whole-food diet. However, gaps are common — especially for vitamins D and B12, iron, calcium, and potassium. Understanding what each nutrient does and where to find it is a practical first step toward closing those gaps.
| Total essential vitamins | 13 (4 fat-soluble, 9 water-soluble) (National Institutes of Health, Office of Dietary Supplements) |
| Total essential minerals | At least 16 recognized as essential for humans (Dietary Reference Intakes, National Academies) |
| Most common U.S. deficiency | Vitamin D, followed by iron and calcium (CDC Second National Report on Biochemical Indicators of Diet and Nutrition) |
| Vitamin D sources | Sun exposure, fatty fish, fortified dairy and plant milks |
| Groups at higher deficiency risk | Older adults, pregnant individuals, vegans/vegetarians, people with limited sun exposure (National Institutes of Health, Office of Dietary Supplements) |
| Best overall strategy | Varied whole-food diet across food groups (2020–2025 Dietary Guidelines for Americans) |
This article is for general informational and educational purposes only. It is not medical advice. If you have concerns about your nutrition or health, consult a qualified healthcare provider before making changes to your diet or taking supplements.
Essential Vitamins: Functions and Food Sources
Vitamins are organic compounds your body cannot produce in sufficient quantities on its own. They fall into two categories:
- Fat-soluble vitamins (A, D, E, K) — stored in body fat and liver; excess can accumulate over time.
- Water-soluble vitamins (C and the B vitamins) — not stored in significant amounts; excess is typically excreted in urine, so regular intake is important.
Micronutrient
A vitamin or mineral required by the body in small amounts to support essential functions like immunity, bone formation, and metabolism. Unlike macronutrients, micronutrients do not provide energy (calories).
Fat-soluble vitamin
Vitamins A, D, E, and K dissolve in fat and are stored in the body's fatty tissues and liver. Because they accumulate, excessive intake from supplements can be harmful.
Water-soluble vitamin
Vitamins C and all B vitamins dissolve in water and are generally not stored in significant quantities. They must be replenished regularly through diet.
Trace mineral
A mineral the body requires in very small amounts — such as iron, zinc, selenium, and iodine. Despite low intake needs, deficiencies can cause significant health problems.
Deficiency
A condition in which the body has insufficient levels of a nutrient to support normal function. Deficiencies range from mild (subtle symptoms) to severe (serious health complications).
Bioavailability
The proportion of a nutrient that the body actually absorbs and uses from food or supplements. Factors like food preparation, gut health, and nutrient interactions all influence bioavailability.
Key Fat-Soluble Vitamins
| Vitamin | Primary Role | Common Sources | Deficiency Signs |
|---|---|---|---|
| A | Vision, immune function, cell growth | Sweet potato, liver, carrots, dairy | Night blindness, dry skin |
| D | Calcium absorption, bone health, immune support | Fatty fish, fortified milk, sunlight exposure | Bone pain, fatigue, muscle weakness |
| E | Antioxidant protection, immune function | Nuts, seeds, vegetable oils, spinach | Nerve damage (rare in healthy adults) |
| K | Blood clotting, bone metabolism | Kale, spinach, broccoli, fermented foods | Excessive bleeding, easy bruising |
Key Water-Soluble Vitamins
| Vitamin | Primary Role | Common Sources | Deficiency Signs |
|---|---|---|---|
| C | Collagen synthesis, antioxidant, iron absorption | Citrus, bell peppers, strawberries, broccoli | Fatigue, slow wound healing, scurvy (severe) |
| B12 | Nerve function, red blood cell production | Meat, fish, dairy, fortified foods | Fatigue, numbness, cognitive changes |
| Folate (B9) | DNA synthesis, cell division | Leafy greens, legumes, fortified grains | Anemia, neural tube risk in pregnancy |
| B6 | Protein metabolism, neurotransmitter production | Poultry, bananas, potatoes, chickpeas | Dermatitis, depression, confusion |
For a deeper look at how nutritional shortfalls show up day-to-day, see our guide to signs you may not be getting enough of a key nutrient.
Essential Minerals: What They Do and Where to Find Them
Minerals are inorganic elements sourced entirely from food and water. Major minerals (needed in larger amounts) include calcium, magnesium, phosphorus, potassium, and sodium. Trace minerals — iron, zinc, selenium, iodine, copper, and manganese — are required in smaller quantities but are no less critical.
~42%
U.S. adults with vitamin D insufficiency
According to a large analysis published in Nutrition Research using NHANES data, roughly 42% of American adults had insufficient vitamin D levels.
10%
U.S. women of childbearing age with iron deficiency
The CDC estimates roughly 1 in 10 women aged 12–49 in the United States has iron deficiency, making it one of the most common nutrient shortfalls.
Over 50%
Americans not meeting potassium intake recommendations
The 2020–2025 Dietary Guidelines for Americans identifies potassium as a nutrient of public health concern due to widespread under-consumption.
| Mineral | Primary Role | Common Sources | Deficiency Signs |
|---|---|---|---|
| Calcium | Bone and tooth structure, muscle contraction, nerve signaling | Dairy, fortified plant milks, leafy greens, tofu | Muscle cramps, low bone density |
| Iron | Oxygen transport in red blood cells | Red meat, lentils, spinach, fortified cereals | Fatigue, pale skin, shortness of breath |
| Magnesium | Enzyme function, blood pressure, muscle and nerve health | Nuts, seeds, whole grains, dark chocolate | Muscle cramps, insomnia, irregular heartbeat |
| Zinc | Immune response, wound healing, taste and smell | Oysters, beef, pumpkin seeds, legumes | Frequent infections, slow healing, hair loss |
| Potassium | Fluid balance, blood pressure regulation, nerve function | Bananas, potatoes, avocados, beans | Muscle weakness, fatigue, irregular heartbeat |
| Iodine | Thyroid hormone production | Iodized salt, seafood, dairy | Thyroid enlargement, fatigue, weight gain |
| Selenium | Antioxidant defense, thyroid function | Brazil nuts, tuna, eggs, sunflower seeds | Muscle weakness, immune dysfunction |
Micronutrients work alongside — not instead of — the energy your body draws from macronutrients and their roles inside your body. Both matter for complete nutrition.