Vitamin requirements are the amounts of each vitamin that health authorities consider adequate for healthy people at different ages and life stages. Knowing these reference values makes it easier to plan meals, read supplement labels, and understand where a varied diet may already be enough — and where gaps are more likely. This page gives a broad overview of how vitamin requirements are defined, what the current recommendations look like for all 13 essential vitamins, how needs change across life stages, and how food and supplements fit into the picture.
Because this is a hub page, it focuses on the map of the topic rather than every detail. More specific questions — such as the signs of a particular deficiency, individual vitamin deep dives, or how specific vitamins interact with specific medications — are explored in the dedicated articles and vitamin guides on this site.
What are vitamin requirements?
When scientists and government agencies talk about vitamin requirements, they are usually referring to a set of reference values rather than a single number. These values describe how much of each vitamin most healthy people in a given age and sex group need each day, based on reviews of nutrient balance studies, dietary intake data, and safety research. In the United States they are maintained by the National Academies and the National Institutes of Health (NIH); in Europe, the European Food Safety Authority (EFSA) sets comparable reference values. Panels of experts review the evidence periodically and update the numbers as the science evolves.
- Recommended Dietary Allowance (RDA): the daily intake expected to meet the needs of about 97–98% of healthy people in a life-stage and sex group.
- Adequate Intake (AI): a value used when evidence is not strong enough to set an RDA; it reflects the average intake observed in healthy populations.
- Tolerable Upper Intake Level (UL): the highest daily intake from food and supplements combined that is unlikely to cause adverse effects.
- Daily Value (DV): the percentage-based figure used on food and supplement labels, based on a general adult reference diet.
Understanding these terms makes it much easier to interpret both official guidance and product labels: RDAs and AIs describe a target to aim for, while ULs describe a ceiling not to exceed over time.
Recommended daily vitamin requirements at a glance
The figures below are approximate daily reference intakes for healthy adults, drawn from U.S. NIH reference values. Amounts are usually listed separately for men and women, and they shift with age and life stage; European (EFSA) reference values follow a similar structure but are not always identical in number.
- Vitamin A: 900 mcg RAE for men, 700 mcg RAE for women.
- Vitamin C: 90 mg for men, 75 mg for women.
- Vitamin D: 15 mcg (600 IU) for adults up to age 70, and 20 mcg (800 IU) after age 70.
- Vitamin E: 15 mg for both men and women.
- Vitamin K: 120 mcg for men and 90 mcg for women (set as an Adequate Intake).
- Vitamin B1 (thiamin): 1.2 mg for men, 1.1 mg for women.
- Vitamin B2 (riboflavin): 1.3 mg for men, 1.1 mg for women.
- Vitamin B3 (niacin): 16 mg NE for men, 14 mg NE for women.
- Vitamin B5 (pantothenic acid): 5 mg for adults (set as an Adequate Intake).
- Vitamin B6: 1.3 mg for adults aged 19–50, rising slightly in later life.
- Vitamin B7 (biotin): 30 mcg for adults (set as an Adequate Intake).
- Vitamin B9 (folate): 400 mcg DFE for adults, increasing during pregnancy.
- Vitamin B12: 2.4 mcg for all adults.
mcg stands for micrograms, mg for milligrams, IU for international units, RAE for retinol activity equivalents, DFE for dietary folate equivalents, and NE for niacin equivalents. These figures are general reference points for healthy adults — not personalized recommendations. Needs during pregnancy and breastfeeding, in childhood and adolescence, and in certain health situations differ, which is why the life-stage detail in the official tables matters. When precision is important, always consult the current tables published by NIH or EFSA.
How vitamin requirements vary by age and life stage
Reference values are organized into life-stage groups because nutrient needs are not constant throughout life. Infants and young children need smaller absolute amounts but relatively high intakes to support rapid growth. Adolescents need more of several vitamins as growth accelerates. Adult needs are broadly stable through mid-life, after which some values change again.
From around age 51 onward, several reference values shift. Vitamin D recommendations rise for adults over 70, and authorities note that absorption or metabolism of some nutrients can become less efficient in later life — vitamin B12 is a well-known example, since absorption from food can decline with age. Alongside older adults, pregnant and breastfeeding women receive the most life-stage-specific guidance, with higher targets for nutrients such as folate.
Vitamin D illustrates why life stage matters so much: it is scarce in most foods, the body also produces it in skin during sun exposure, and needs rise in later life. If you want to look more closely at this vitamin, our vitamin D collection gathers guidance on benefits, sources, and safety in one place.
Food sources for all 13 essential vitamins
A varied, balanced eating pattern can cover most or all of these targets for many people. Each vitamin is concentrated in different foods, which is why variety across the food groups matters more than any single 'superfood'. The list below shows widely cited food sources for each of the 13 essential vitamins.
- Vitamin A: sweet potatoes, carrots, spinach, liver, and dairy products.
- Vitamin C: citrus fruit, bell peppers, strawberries, and broccoli.
- Vitamin D: oily fish such as salmon and sardines, plus fortified milk and fortified plant-based drinks.
- Vitamin E: sunflower seeds, almonds, and vegetable oils.
- Vitamin K: leafy greens such as kale and spinach, plus fermented foods like natto.
- Vitamin B1 (thiamin): whole grains, pork, legumes, and sunflower seeds.
- Vitamin B2 (riboflavin): milk, yogurt, eggs, and fortified cereals.
- Vitamin B3 (niacin): poultry, tuna, peanuts, and brown rice.
- Vitamin B5 (pantothenic acid): chicken, avocado, mushrooms — and small amounts in most foods.
- Vitamin B6: chickpeas, salmon, potatoes, and bananas.
- Vitamin B7 (biotin): cooked eggs, nuts, seeds, and sweet potato.
- Vitamin B9 (folate): leafy greens, asparagus, beans, lentils, and fortified grains.
- Vitamin B12: meat, fish, eggs, dairy, and fortified foods.
People who follow vegan or predominantly plant-based diets pay particular attention to vitamin B12, because reliable natural plant sources are limited and fortified foods or supplements are commonly recommended in official guidance. The B vitamins as a group appear across many different food groups, and our vitamin B collection provides a closer look at each of them.
Upper limits: how much is too much?
Every vitamin has a level beyond which intake stops being simply 'more' and becomes a safety question. For several vitamins, expert bodies have set a Tolerable Upper Intake Level (UL) — the maximum daily amount from food and supplements combined that is unlikely to cause adverse effects in almost all healthy people. Established upper levels exist for vitamin A, vitamin C, vitamin D, vitamin E, niacin (vitamin B3), vitamin B6, and folate. For the remaining vitamins no UL has been set, usually because the data are limited rather than because unlimited intake is automatically safe.
In practice, staying below the upper level is rarely difficult through food alone. It becomes more relevant when high-dose products are combined — for example, a multivitamin plus separate high-strength single vitamins — so it is worth adding up your total intake from all products you use. Supplement labels list the amount per serving, and the % Daily Value helps you see how a product relates to general adult targets.
Two practical cautions apply. First, more is not automatically better: intakes above the UL are not known to add benefit and may, for some vitamins, raise safety concerns over time. Second, some vitamins can interact with prescription medicines, so anyone taking medication should mention their supplement use to a doctor or pharmacist. These are general safety considerations rather than medical advice; a qualified professional can assess your individual situation.
Meeting your vitamin requirements in practice
For most healthy people, the starting point is a food-first pattern: plenty of vegetables and fruit, whole grains, quality protein sources, and dairy or fortified alternatives, with oily fish and nuts or seeds in the mix. Eating across all the main food groups on a regular basis is the most reliable way to approach the full set of 13 vitamins, because different foods carry different nutrients.
Where diet falls short — due to restricted diets, limited sun exposure, specific life stages, or simply personal preferences — fortified foods and supplements can help fill the gap. A multivitamin is one option some people use as a broad daily baseline, though it is a supplement to a varied diet rather than a replacement for it. Our multivitamins guide covers ingredients, usage, and safety considerations in more detail.
A simple way to use this page: check the adult values above, scan the food-source list for the vitamins you may be eating less often, and read the label of any supplement you already take to see where it fits. If you suspect a deficiency or have a health condition, seek personalized advice from a qualified professional rather than self-prescribing high doses.
Frequently asked questions about vitamin requirements
What are the daily requirements for vitamins?
They are the reference values — mainly RDAs and Adequate Intakes — that expert bodies such as the U.S. NIH and European EFSA publish for each vitamin, broken down by age, sex, and life stage. For healthy adults, examples include 90 mg of vitamin C per day for men and 75 mg for women, and 2.4 mcg of vitamin B12 for all adults. The full adult list appears above; the official tables add detail for children, teenagers, older adults, and pregnancy.
What are the five must-have vitamins?
There is no official 'top five' — all 13 essential vitamins are needed, and each has its own place in the diet. Public health guidance most often highlights vitamin D, folate, vitamin B12, vitamin A, and vitamin C, because these are the vitamins most frequently addressed in fortification programs and life-stage advice. Which ones deserve your attention depends on your diet, age, and circumstances rather than on a universal list.
How can I get all 13 essential vitamins?
Through variety: build meals from all the main food groups, include vegetables and fruit of different colors, choose whole grains, and rotate protein sources such as fish, eggs, dairy or fortified alternatives, and legumes. Fortified foods can help cover common gaps such as vitamin D and vitamin B12, and supplements can be useful where intake is consistently low. If you want a structured check, compare your weekly meals against the food-source list above.
Vitamin requirements are the foundation for almost every other question about vitamins: how much to take, whether a supplement is needed, and what a balanced daily intake looks like. Use this page as your reference point, and explore the individual vitamin guides and articles on this site for deeper detail on specific nutrients, sources, and safety considerations.
