Micronutrients: The Vitamins and Minerals Your Body Can't Make Itself

What Are Micronutrients and Why Do They Matter?

Unlike carbohydrates, proteins, and fats, which supply energy in large quantities, micronutrients are needed in smaller amounts — yet they're no less critical. Vitamins and minerals regulate nearly every biological process: immune defense, bone maintenance, nerve signaling, blood clotting, and energy metabolism all depend on them.

The defining feature of micronutrients is that the human body either cannot synthesize them at all or cannot produce enough to meet its needs. That means diet — and sometimes supplementation under medical guidance — is the only reliable source.

For a broader foundation before diving into individual nutrients, see Nutrition from Scratch.

Fat-Soluble Vitamins: A, D, E, and K

Fat-soluble vitamins are stored in body fat and the liver, which means both deficiency and excess can accumulate over time. They require dietary fat for absorption.

• Vitamin A — Supports vision (especially in low light), skin cell turnover, and immune function. Found in liver, dairy, eggs, and in the form of beta-carotene in orange and leafy green vegetables.
• Vitamin D — Essential for calcium absorption and bone density; also plays a role in immune regulation. The body can produce it through skin exposure to UVB sunlight, but many adults in northern latitudes or with limited sun exposure fall short. Dietary sources include fatty fish, fortified dairy, and egg yolks.
• Vitamin E — An antioxidant that protects cell membranes from oxidative damage. Found in nuts, seeds, wheat germ, and vegetable oils.
• Vitamin K — Critical for blood clotting and bone metabolism. Vitamin K1 is abundant in dark leafy greens; K2 is found in fermented foods and some animal products.

Water-Soluble Vitamins: The B Complex and Vitamin C

Water-soluble vitamins are not stored in significant quantities, so regular dietary intake is important. Excess amounts are generally excreted in urine, though very high supplemental doses of certain B vitamins can still cause adverse effects.

• B1 (Thiamine) — Converts carbohydrates into usable energy; supports nerve function. Found in whole grains, pork, and legumes.
• B2 (Riboflavin) — Involved in energy production and cellular repair. Sources include dairy, eggs, lean meat, and almonds.
• B3 (Niacin) — Supports DNA repair and metabolic reactions. Found in poultry, fish, peanuts, and fortified grains.
• B6 (Pyridoxine) — Needed for protein metabolism and neurotransmitter synthesis. Sources include chickpeas, bananas, fish, and poultry.
• B9 (Folate) — Critical for DNA synthesis and cell division; especially important during pregnancy. Found in leafy greens, lentils, and fortified grain products.
• B12 (Cobalamin) — Maintains nerve health and red blood cell formation. Found almost exclusively in animal products; a common concern for those following plant-based diets.
• Vitamin C — An antioxidant that supports immune function, collagen synthesis, and iron absorption from plant foods. Abundant in citrus fruits, bell peppers, strawberries, and broccoli.

Water intake also plays a role in how water-soluble vitamins are transported and excreted throughout the body.

Essential Minerals: What Each One Does

Minerals are inorganic elements that serve structural and regulatory roles. Major minerals are needed in larger amounts; trace minerals are required in smaller quantities but are equally indispensable.

• Calcium — The most abundant mineral in the body, primarily in bones and teeth. Also involved in muscle contraction and nerve transmission. Found in dairy, fortified plant milks, and leafy greens like kale and bok choy.
• Iron — Required for hemoglobin, the protein that carries oxygen in red blood cells. Heme iron from meat is absorbed more readily than non-heme iron from plants; pairing plant iron sources with vitamin C improves absorption.
• Magnesium — Involved in more than 300 enzymatic reactions, including energy production and muscle relaxation. Found in nuts, seeds, legumes, and whole grains.
• Zinc — Supports immune function, wound healing, and protein synthesis. Found in shellfish, red meat, legumes, and pumpkin seeds.
• Potassium — Regulates fluid balance and blood pressure and supports heart rhythm. Abundant in bananas, potatoes, beans, and leafy greens.
• Iodine — Essential for thyroid hormone production. Primary sources are iodized salt, seafood, and dairy.
• Selenium — An antioxidant mineral that supports thyroid function and immune health. Found in Brazil nuts, seafood, and whole grains.

Nutrient needs shift across life stages — see how requirements evolve with age for more context.

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