Micronutrients: A Plain-English Reference to Vitamins and Minerals

What Are Micronutrients and Why Do They Matter?

Macronutrients—carbohydrates, protein, and fat—get most of the attention in nutrition conversations, but micronutrients are equally essential. Vitamins and minerals are collectively called micronutrients because the body needs them in relatively small amounts compared to macronutrients. That said, small amounts can have an enormous impact. They regulate nearly every biological process: energy metabolism, immune defense, bone maintenance, blood clotting, and nerve signaling, among many others.

Unlike macronutrients, the body cannot manufacture most vitamins and minerals on its own, which means they must come from food—or, when diet falls short, from supplements under professional guidance. If you're just starting to think about nutrition, see our foundational nutrition guide for a broader overview of how all nutrients fit together.

Key Vitamins: Fat-Soluble vs. Water-Soluble

Vitamins fall into two categories based on how the body stores and transports them. Understanding the difference helps explain why some deficiencies develop slowly while others appear quickly.

Fat-Soluble Vitamins (A, D, E, K)

These dissolve in fat and are stored in body tissues and the liver. Because they accumulate, both deficiency and excess can be harmful over time—a reason why high-dose supplements should only be taken under medical supervision.

• Vitamin A — Supports vision (especially in low light), immune function, and skin integrity. Found in liver, dairy, eggs, and orange-yellow vegetables like carrots and sweet potatoes.
• Vitamin D — Critical for calcium absorption, bone density, and immune modulation. The skin produces it when exposed to sunlight; dietary sources include fatty fish, fortified dairy, and egg yolks.
• Vitamin E — Acts as an antioxidant, protecting cells from oxidative damage. Found in nuts, seeds, vegetable oils, and leafy greens.
• Vitamin K — Essential for blood clotting and bone metabolism. Leafy greens (kale, spinach) and fermented foods are primary sources.

Water-Soluble Vitamins (C and B-Complex)

These are not stored in significant amounts, so regular dietary intake is important. Excess is usually excreted in urine, which reduces toxicity risk—but it also means deficiencies can develop faster.

• Vitamin C — An antioxidant that supports immune function, wound healing, and iron absorption. Citrus fruits, bell peppers, and broccoli are excellent sources.
• B Vitamins (B1, B2, B3, B5, B6, B7, B9, B12) — This group collectively supports energy metabolism, red blood cell production, and nervous system health. B12, found almost exclusively in animal products, is a common concern for those following plant-based diets.
• Folate (B9) — Crucial for DNA synthesis and cell division. Especially important during pregnancy for neural tube development. Found in legumes, leafy greens, and fortified grains.

Essential Minerals: Macrominerals and Trace Minerals

Minerals are inorganic elements that support structure (bones and teeth) and function (fluid balance, nerve transmission, enzyme activity). They divide into macrominerals—needed in larger amounts—and trace minerals, required in tiny but critical quantities.

Macrominerals

• Calcium — The most abundant mineral in the body; builds and maintains bone and tooth strength, aids muscle contraction and nerve transmission. Found in dairy, fortified plant milks, tofu, and leafy greens.
• Magnesium — Involved in over 300 enzymatic reactions, including energy production and muscle and nerve function. Nuts, seeds, whole grains, and dark chocolate are good sources.
• Potassium — Helps regulate fluid balance, nerve signals, and muscle contractions, including the heart. Bananas, potatoes, beans, and avocados are rich sources.
• Sodium — Necessary for fluid balance and nerve function, though most Americans consume more than recommended. Most dietary sodium comes from processed and restaurant foods.

Trace Minerals

• Iron — Essential for making hemoglobin, the protein in red blood cells that carries oxygen. Heme iron (from meat) is more readily absorbed than non-heme iron (from plants); pairing plant sources with vitamin C improves absorption.
• Zinc — Supports immune function, wound healing, and DNA synthesis. Found in meat, shellfish, legumes, and seeds.
• Iodine — Required for thyroid hormone production, which regulates metabolism. Iodized salt and seafood are primary sources.
• Selenium — An antioxidant mineral that supports thyroid function and immune response. Brazil nuts are exceptionally high in selenium; other sources include fish and whole grains.

When planning your weekly meals to cover these nutrients, our meal planning checklist offers a practical structure. And to decode the %DV figures on food packaging, see our guide to reading a Nutrition Facts label.

This article is for general informational and educational purposes only and is not a substitute for professional medical or dietary advice. Talk with a qualified healthcare provider or registered dietitian before making significant changes to your diet or starting any supplement regimen.