Micronutrients at a Glance: A Plain-Language Reference Guide

What Are Micronutrients — and Why Do They Matter?

Micronutrients are vitamins and minerals your body requires in relatively small amounts but cannot function properly without. Unlike macronutrients — proteins, fats, and carbohydrates — they provide no calories. Instead, they act as essential catalysts: enabling enzyme reactions, supporting immune defenses, building bone, synthesizing hormones, and converting food into usable energy. For a deeper look at what macronutrients do alongside these nutrients, see what macronutrients actually do in your body.

Micronutrient shortfalls are more common than many people realize. A diet heavy in ultra-processed foods can supply adequate calories while leaving meaningful gaps in vitamins and minerals. This reference guide is designed as a quick-lookup resource — not a prescription — to help you understand what each key nutrient does and where to find it in food.

This article is for general informational purposes only and is not a substitute for professional medical or dietary advice. Consult a qualified healthcare provider before making significant changes to your diet or considering supplementation.

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

Fat-soluble vitamins dissolve in dietary fat and can be stored in the body's fatty tissues and liver. Because they accumulate, both deficiency and excessive supplementation carry risks — a reason to prioritize food sources over high-dose supplements unless directed by a clinician.

• Vitamin A — Supports vision (especially night vision), immune function, and skin integrity. Food sources: liver, dairy, eggs, and orange-yellow produce (beta-carotene in carrots and sweet potatoes is converted to vitamin A in the body).
• Vitamin D — Critical for calcium absorption, bone strength, and immune regulation. Synthesized in skin exposed to UVB sunlight; dietary sources include fatty fish, egg yolks, and fortified foods.
• Vitamin E — Acts as an antioxidant protecting cell membranes from oxidative damage. Found in nuts, seeds, vegetable oils, and leafy greens.
• Vitamin K — Essential for blood clotting (K1, found in green vegetables) and bone metabolism (K2, found in fermented foods and some animal products).

The Water-Soluble Vitamins: C and the B Complex

Water-soluble vitamins are not stored in significant amounts; excess is generally excreted in urine. Consistent daily intake through varied food choices is the most straightforward way to maintain adequate levels.

• Vitamin C — Antioxidant; supports collagen synthesis, immune function, and iron absorption from plant foods. Citrus fruits, bell peppers, broccoli, and strawberries are among the richest sources.
• B1 (Thiamine) — Converts carbohydrates into energy; supports nerve function. Found in whole grains, legumes, and pork.
• B2 (Riboflavin) — Energy metabolism and cellular growth. Sources: dairy, eggs, lean meats, and fortified cereals.
• B3 (Niacin) — DNA repair, energy production, and skin health. Found in poultry, fish, peanuts, and enriched grains.
• B6 — Amino acid metabolism and neurotransmitter synthesis. Chickpeas, fish, poultry, potatoes, and bananas are good sources.
• B9 (Folate) — DNA synthesis and cell division; especially important during pregnancy. Abundant in dark leafy greens, legumes, and fortified foods.
• B12 — Nerve function, red blood cell formation, and DNA synthesis. Found almost exclusively in animal products; a key nutrient to monitor on plant-forward diets. See plant-based eating nutrient gaps for context.

When reading a nutrition label, the % Daily Value listed for these vitamins gives a quick benchmark against established reference amounts.

Key Minerals: Calcium, Iron, Magnesium, Zinc, and More

Minerals are inorganic elements sourced entirely from food and water. They participate in bone structure, fluid balance, oxygen transport, and hundreds of enzymatic reactions.

• Calcium — The most abundant mineral in the body; critical for bone density, muscle contraction, and nerve signaling. Dairy, fortified plant milks, tofu made with calcium sulfate, and leafy greens (kale, bok choy) are reliable sources.
• Iron — Carries oxygen in hemoglobin. Heme iron (from meat and seafood) is more readily absorbed than non-heme iron (from legumes, tofu, and fortified cereals). Pairing non-heme sources with vitamin C improves absorption.
• Magnesium — Involved in over 300 enzyme reactions, including energy production and muscle relaxation. Found in nuts, seeds, whole grains, and dark chocolate.
• Potassium — Regulates fluid balance, blood pressure, and muscle contractions. Bananas, potatoes, beans, and leafy greens are excellent sources.
• Zinc — Immune function, wound healing, and protein synthesis. Oysters are exceptionally rich; beef, pumpkin seeds, and legumes also contribute meaningfully.
• Sodium — Necessary for fluid balance and nerve transmission, though most Americans consume well above recommended levels through processed food.
• Selenium — Antioxidant defense and thyroid hormone metabolism. Brazil nuts, seafood, and eggs are notable sources.

For practical guidance on stocking foods that cover these nutrient bases, building a nutritionally sound grocery list offers a structured starting point.