| Number of recognized vitamins | 13 essential vitamins (National Institutes of Health (NIH)) |
| Fat-soluble vitamins | A, D, E, K |
| Water-soluble vitamins | C and 8 B vitamins |
| Key macrominerals | Calcium, magnesium, phosphorus, potassium, sodium |
| Iron absorption boost | Up to 3x more non-heme iron absorbed with vitamin C (General nutrition science consensus) |
| Adults with inadequate vitamin D | Estimated 35% of US adults (Nutritional research estimates vary; consult a provider for personal status) |
What Are Micronutrients — and Why Do They Matter?
When most people think about nutrition, they think about calories, protein, carbs, and fat. But alongside these macronutrients, your body depends on a separate class of compounds — micronutrients — to function normally. Unlike macronutrients, micronutrients don't supply energy directly. Instead, they act as essential regulators: enabling chemical reactions, supporting immune defenses, maintaining bone integrity, and helping convert food into usable fuel.
Micronutrients divide into two broad categories: vitamins (organic compounds made by plants or animals) and minerals (inorganic elements drawn from soil and water). Together, they number in the dozens, and most must come from food because the body either can't make them at all or can't make enough. For a broader look at how these fit into your overall diet, see our guide to macronutrients.
Micronutrient
Vitamins and minerals required by the body in small amounts to support normal physiological functions. Unlike macronutrients, they do not provide calories.
Fat-soluble vitamin
Vitamins (A, D, E, K) that dissolve in fat and are stored in body tissues. Because they accumulate, excessive intake — particularly from supplements — can potentially reach harmful levels.
Water-soluble vitamin
Vitamins (C and B-complex) that dissolve in water and are not stored in significant amounts. Regular dietary intake is needed to maintain adequate levels.
Trace mineral
A mineral the body requires in very small quantities — such as iron, zinc, or selenium — that still plays an essential role in health and normal metabolic function.
Heme iron
A form of iron found in animal-based foods such as meat and fish that the body absorbs more efficiently than non-heme iron from plant sources.
Bioavailability
The proportion of a nutrient that the body actually absorbs and can use. It varies depending on the food source, preparation method, and other nutrients consumed at the same time.
Key Vitamins: Roles and Food Sources
Vitamins split into two groups based on how the body handles them:
- Fat-soluble vitamins (A, D, E, K) are stored in fatty tissue and the liver. Because they accumulate, consistently high intake — particularly from supplements — can reach harmful levels over time.
- Water-soluble vitamins (C and the eight B vitamins) are not stored in meaningful amounts, so regular dietary intake matters. Excess is generally excreted in urine, though very high doses of some can still cause problems.
Here's a concise look at several widely studied vitamins:
| Vitamin | General Role | Common Food Sources |
|---|---|---|
| A | Vision, immune function, cell growth | Liver, dairy, orange and yellow vegetables |
| C | Antioxidant activity, collagen synthesis, immune support | Citrus, bell peppers, strawberries, broccoli |
| D | Calcium absorption, bone health, immune modulation | Fatty fish, egg yolks, fortified milk; synthesized via sunlight |
| B12 | Nerve function, red blood cell formation, DNA synthesis | Meat, fish, dairy, eggs; fortified plant foods |
| Folate (B9) | DNA replication, cell division — critical during early pregnancy | Leafy greens, legumes, fortified grains |
| K | Blood clotting, bone metabolism | Leafy greens, fermented foods, some vegetable oils |
Knowing which vitamins appear on a food label — and in what amounts — is a useful skill. Our guide to reading nutrition labels walks through exactly how to interpret those figures.
Essential Minerals: What They Do and Where to Find Them
Minerals are grouped by the quantity the body requires. Macrominerals — including calcium, magnesium, phosphorus, potassium, and sodium — are needed in larger amounts. Trace minerals — such as iron, zinc, selenium, iodine, and copper — are required in smaller quantities but are no less essential.
| Number of recognized vitamins | 13 essential vitamins (National Institutes of Health (NIH)) |
| Fat-soluble vitamins | A, D, E, K |
| Water-soluble vitamins | C and 8 B vitamins |
| Key macrominerals | Calcium, magnesium, phosphorus, potassium, sodium |
| Iron absorption boost | Up to 3x more non-heme iron absorbed with vitamin C (General nutrition science consensus) |
| Adults with inadequate vitamin D | Estimated 35% of US adults (Nutritional research estimates vary; consult a provider for personal status) |
A few minerals merit particular attention:
- Calcium — Best known for bone and teeth structure, it also plays a role in muscle contraction and nerve signaling. Dairy, fortified plant milks, and leafy greens are common sources.
- Iron — Central to oxygen transport via hemoglobin. Found in red meat (heme iron, absorbed more readily) and plant sources like lentils and spinach (non-heme iron).
- Magnesium — Involved in hundreds of enzymatic reactions, including energy production and muscle function. Nuts, seeds, whole grains, and dark chocolate are good sources.
- Zinc — Supports immune response, wound healing, and taste perception. Found in shellfish, meat, legumes, and pumpkin seeds.
- Iodine — Essential for thyroid hormone production, which regulates metabolism. Iodized salt and seafood are primary sources in the US diet.
Getting Enough: Food First, Supplements Second
A varied diet built around whole foods — vegetables, fruits, legumes, whole grains, lean proteins, and dairy or fortified alternatives — generally provides a broad micronutrient profile without requiring supplementation for most healthy adults. Certain groups may have higher needs or limited dietary access: people who are pregnant, older adults, those following restrictive diets, or individuals with specific absorption issues may benefit from targeted supplementation. However, supplementation decisions should always be made in consultation with a qualified healthcare provider, not based solely on general information.
It's also worth remembering that micronutrients work best as part of an integrated approach to eating. Nutrients interact — vitamin C enhances iron absorption from plant sources, while vitamin D is necessary for calcium to do its job. Sustainable food habits that support energy and wellbeing are covered in our piece on eating for energy. And don't overlook hydration: water plays a supporting role in how your body transports and uses many of these nutrients, as explored in our article on hydration and nutrition.
This article is for general informational and educational purposes only and is not a substitute for professional medical or dietary advice. Always consult a qualified healthcare professional before making changes to your diet or starting any supplement regimen.