| Total essential vitamins | 13 (Established by nutritional science consensus) |
| Fat-soluble vitamins | A, D, E, K |
| B vitamins in the complex | 8 (B1, B2, B3, B5, B6, B7, B9, B12) |
| Recognized essential minerals | ~16 (major + trace) (Dietary Reference Intakes, National Academies) |
| Vitamin most often synthesized by skin | Vitamin D |
| Most common nutrient deficiency worldwide | Iron deficiency (World Health Organization) |
What Micronutrients Are — and Why They're Non-Negotiable
Your body runs on two broad categories of nutrients: macronutrients (carbohydrates, proteins, and fats) and micronutrients. While macronutrients supply energy, micronutrients — vitamins and minerals — drive virtually every biological process that keeps you functioning. For a fuller picture of how the two categories work together, see our macronutrients explainer.
The defining characteristic of micronutrients is that your body either cannot synthesize them at all, or cannot produce them in sufficient quantities to meet its needs. That makes dietary intake essential — not optional. The term "essential" in nutrition science has a specific meaning: the body requires the nutrient for normal function and must obtain it from food or, in some cases, supplementation.
Micronutrients are needed only in small amounts — milligrams or micrograms per day — but their effects are far-reaching. They regulate metabolism, support immune defense, enable nerve signaling, strengthen bones, and protect cells from damage.
Micronutrient
A vitamin or mineral required by the body in small amounts to support normal biological functions. Unlike macronutrients, micronutrients do not supply calories.
Essential nutrient
A nutrient the body cannot synthesize in adequate amounts on its own and must therefore obtain from food or supplementation.
Fat-soluble vitamin
A vitamin (A, D, E, or K) that dissolves in fat and is stored in the body's fatty tissues and liver, allowing reserves to build up over time.
Water-soluble vitamin
A vitamin (C or any of the eight B vitamins) that dissolves in water and is generally not stored in large amounts, making regular dietary intake important.
Trace mineral
A mineral required by the body in very small amounts — typically less than 100 mg per day — such as iron, zinc, iodine, and selenium.
Bioavailability
The proportion of a nutrient that the body is able to absorb and use after it is consumed. Bioavailability can vary based on the food source, preparation method, and individual factors.
Vitamins: Fat-Soluble vs. Water-Soluble
The 13 recognized essential vitamins fall into two groups based on how the body stores and handles them.
Fat-Soluble Vitamins (A, D, E, K)
These dissolve in fat and are stored in fatty tissue and the liver. Because the body retains them, excessive intake — typically from high-dose supplements rather than food — can accumulate to harmful levels. Good dietary sources include:
- Vitamin A: liver, dairy, eggs, and provitamin A carotenoids in orange and dark-green vegetables
- Vitamin D: fatty fish, egg yolks, and fortified foods (the skin also synthesizes it from sunlight, but many people still fall short)
- Vitamin E: nuts, seeds, wheat germ, and vegetable oils
- Vitamin K: leafy greens such as kale, spinach, and broccoli
Water-Soluble Vitamins (C and the B Vitamins)
These dissolve in water and are not stored in meaningful amounts, so regular dietary intake matters more. They include vitamin C and eight B vitamins — thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), B6, biotin (B7), folate (B9), and B12. Rich sources span citrus fruits, berries, legumes, whole grains, meat, poultry, fish, and dairy.
| Total essential vitamins | 13 (Established by nutritional science consensus) |
| Fat-soluble vitamins | A, D, E, K |
| B vitamins in the complex | 8 (B1, B2, B3, B5, B6, B7, B9, B12) |
| Recognized essential minerals | ~16 (major + trace) (Dietary Reference Intakes, National Academies) |
| Vitamin most often synthesized by skin | Vitamin D |
| Most common nutrient deficiency worldwide | Iron deficiency (World Health Organization) |
Minerals: Major and Trace
Minerals are inorganic elements absorbed from food and water. They are grouped by how much the body requires daily.
Major Minerals
Calcium, phosphorus, magnesium, sodium, potassium, chloride, and sulfur are needed in larger amounts (generally more than 100 mg per day). Calcium and phosphorus together account for most of the body's bone mass. Magnesium participates in over 300 enzymatic reactions. Potassium and sodium work in balance to regulate fluid levels and blood pressure.
Trace Minerals
Iron, zinc, iodine, selenium, copper, manganese, fluoride, and chromium are required in smaller quantities but are no less critical. Iron carries oxygen in red blood cells. Iodine is essential for thyroid hormone production. Zinc supports immune function and wound healing. Selenium acts as an antioxidant and supports thyroid metabolism.
Older adults often need particular attention to several of these nutrients. Our article on nutrients under-consumed in later life explains which are most at risk and why.
Getting Micronutrients From Food — and Knowing When You May Fall Short
Whole foods deliver micronutrients within a matrix of fiber, phytonutrients, and other compounds that appear to support absorption and utilization in ways that isolated supplements may not fully replicate. Dietary variety is the most effective strategy: a plate that includes colorful vegetables, fruits, whole grains, lean proteins, legumes, and dairy (or fortified alternatives) covers the widest micronutrient range.
That said, gaps do occur. Common risk factors include highly restrictive diets, poor appetite, certain medical conditions, malabsorption disorders, and life stages with elevated needs such as pregnancy or older age. For guidance on assembling meals that cover both macro and micronutrient bases, see our guide to building a nutritionally complete meal.
Subtle shortfalls don't always announce themselves with obvious symptoms, which is why awareness matters. Learn more about what to watch for in our article on signs your diet might be missing key nutrients.
Supplements Are Not a Universal Fix
While supplements can address clinically confirmed deficiencies, they are not equivalent to a balanced diet and are not recommended as a routine substitute for food-based nutrients. Some vitamins and minerals interact with medications or other nutrients, and fat-soluble vitamins can accumulate to unsafe levels with excessive supplementation. Always consult a healthcare provider before starting any supplement regimen.
This article provides general nutrition education and is not a substitute for personalized medical or dietary advice. If you have concerns about your nutrient intake, speak with a registered dietitian or your healthcare provider.