Micronutrients at a Glance: Key Vitamins and Minerals Explained

What Are Micronutrients — and Why Do They Matter?

Unlike macronutrients like carbs, protein, and fat, micronutrients — vitamins and minerals — are needed in small amounts, but their impact on health is anything but small. They regulate virtually every process in the body: energy production, immune defense, bone maintenance, nerve signaling, and more.

Vitamins are organic compounds; minerals are inorganic elements absorbed from soil and water through food. Both categories are considered essential, meaning the body cannot synthesize adequate amounts on its own and must obtain them through diet. Falling short — even modestly — can have measurable health consequences over time.

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

Fat-soluble vitamins are stored in fatty tissue and the liver, so they don't need to be consumed daily — but they can accumulate to excess if over-supplemented.

• Vitamin A — Supports vision (especially night vision), immune function, and skin integrity. Found in liver, dairy, eggs, and as beta-carotene in orange and leafy vegetables. Deficiency is a leading cause of preventable blindness globally.
• Vitamin D — Promotes calcium absorption for bone health and plays a role in immune regulation. Synthesized in the skin upon sun exposure; dietary sources include fatty fish and fortified foods. Deficiency is common, particularly in northern latitudes and among older adults.
• Vitamin E — Acts as an antioxidant, protecting cell membranes. Found in nuts, seeds, and vegetable oils. Isolated deficiency is rare in healthy adults.
• Vitamin K — Essential for blood clotting and bone metabolism. K1 is found in leafy greens; K2 in fermented foods and some animal products.

Water-Soluble Vitamins: The B Complex and Vitamin C

Water-soluble vitamins are not stored in large quantities — excess is typically excreted — so regular dietary intake is important.

• Vitamin C — Supports collagen synthesis, immune function, and iron absorption. Found in citrus, bell peppers, and broccoli. Severe deficiency leads to scurvy, now rare in developed countries.
• Folate (B9) — Critical for DNA synthesis and cell division, especially during early pregnancy. Found in leafy greens, legumes, and fortified grains. Inadequate intake during pregnancy is linked to neural tube defects.
• Vitamin B12 — Necessary for nerve function and red blood cell formation. Found almost exclusively in animal products; vegans and older adults are at higher risk of deficiency. Deficiency can cause neurological damage if left unaddressed.
• Other B vitamins (B1/thiamine, B2/riboflavin, B3/niacin, B5, B6, B7/biotin) play roles in energy metabolism, enzyme function, and neurotransmitter production. Most are widely available across a varied diet.

For guidance on reading vitamin content on food packaging, see how nutrition labels display daily values.

Essential Minerals: From Calcium to Zinc

Minerals fall into two groups: macrominerals (needed in larger amounts, such as calcium and magnesium) and trace minerals (needed in smaller amounts, such as iron and zinc).

• Calcium — The most abundant mineral in the body, critical for bone and tooth structure, muscle contraction, and nerve transmission. Found in dairy, fortified plant milks, and leafy greens like kale.
• Iron — Carries oxygen in the blood via hemoglobin. Heme iron (from meat and fish) is more readily absorbed than non-heme iron (from plants). Deficiency is the most common nutritional deficiency worldwide, particularly among women of reproductive age.
• Magnesium — Involved in over 300 enzymatic reactions, including energy production and muscle relaxation. Found in nuts, seeds, legumes, and whole grains.
• Zinc — Supports immune function, wound healing, and taste perception. Found in shellfish (especially oysters), meat, seeds, and legumes.
• Potassium — Regulates fluid balance and blood pressure. Found in bananas, potatoes, beans, and leafy greens.
• Selenium and iodine — Selenium acts as an antioxidant and supports thyroid function; iodine is required for thyroid hormone synthesis. Iodized salt and seafood are key sources.

Nutrient needs also shift with age — something covered in depth in our guide on how nutritional requirements change across adulthood.

Getting Enough: Food First, Supplements as a Safety Net

Nutrition researchers broadly agree that obtaining micronutrients from whole foods is preferable to supplementation for most healthy adults. Whole foods deliver nutrients alongside fiber, phytonutrients, and other compounds that influence how those nutrients are absorbed and used. This is discussed in our overview of the role macronutrients play alongside micronutrients.

Supplements may be appropriate in specific circumstances — pregnancy (folate and iron), veganism (B12), limited sun exposure (vitamin D), or diagnosed deficiencies — but supplementing without a clinical reason can occasionally cause harm, particularly with fat-soluble vitamins that accumulate in tissue.

This article is for general informational purposes only and does not constitute medical or dietary advice. If you are concerned about a nutritional deficiency or considering supplementation, consult a registered dietitian or qualified healthcare provider.