By supplement · 26 guides

Explore vitamins A, B, C, D, E, and K — their health benefits, food sources, daily requirements, and safe supplementation.

Latest guide
Folate and folic acid are both forms of vitamin B9, but they're absorbed differently. Learn how to choose folate-rich foods, understand supplement labels, avoid unnecessary high doses, and get the right amount of folic acid to support a healthy pregnancy.
8 min read · 5 sources · Oct 26, 2026

What happens to vitamins after you eat? Discover how your body absorbs fat-soluble and water-soluble vitamins, and which everyday habits can support nutrient absorption.
12 min read · Updated Oct 27, 2026

Vitamin B12 deficiency can affect your energy, nerves, and concentration. Discover what causes low B12, who's most at risk, how to recognize the symptoms, and why early diagnosis matters for preventing long-term nerve damage.
11 min read · Updated Oct 27, 2026

Vitamin D helps your body absorb calcium, but do you need both as supplements? Discover how they support bone health, which foods provide them, and how to avoid unnecessary supplementation.
10 min read · Updated Oct 27, 2026

Vitamin B6 supports protein metabolism, nervous-system function, hemoglobin formation, and immune health, while foods like chickpeas, fish, poultry, potatoes, and bananas can help meet daily needs.
9 min read · Updated Oct 27, 2026

B vitamins can usually be taken at flexible times, with or without food, but supplement doses and overlapping products matter more than the exact hour of the day.
10 min read · Updated Oct 27, 2026

A varied diet can provide most B vitamins through foods such as fish, meat, eggs, dairy, legumes, whole grains, nuts, seeds, and vegetables, while vitamin B12 needs special attention in vegan diets.
10 min read · Updated Oct 27, 2026

B vitamins help the body use energy from food, but they do not provide calories or act like stimulants. Extra B vitamins are most useful when a deficiency is present.
9 min read · Updated Oct 27, 2026

B vitamins support energy metabolism, blood formation, DNA production, and nervous-system function, but a B-complex supplement is not necessary for everyone.
10 min read · Updated Oct 27, 2026

Vitamin B12 supports red blood cell formation, DNA production, and nervous-system function, while food sources, absorption, and deficiency risk can vary widely between individuals.
8 min read · Updated Oct 27, 2026

Folate supports DNA production, healthy cell division, and red blood cell formation, while folic acid plays a key role before and during early pregnancy.
10 min read · Updated Oct 27, 2026

What vitamin B7 (biotin) does, how much you need each day, the best food sources, deficiency signs, hair and nail claims, and supplement safety.
10 min read · Updated Oct 27, 2026

What vitamin B3 (niacin) does, how much you need each day, the best food sources, pellagra and deficiency risks, and what to know about supplements and niacin flush.
9 min read · Updated Oct 27, 2026

What vitamin B5 (pantothenic acid) does, how much you need each day, the best food sources, deficiency risks, and what to know about supplements and safety.
7 min read · Updated Oct 27, 2026

What vitamin B2 (riboflavin) does, how much you need each day, the best food sources, deficiency signs, and what to know about supplements.
9 min read · Updated Oct 29, 2026

What vitamin B1 (thiamin) does, how much you need each day, the best food sources, deficiency risks, and what to know about supplements.
7 min read · Updated Oct 27, 2026

What research and nutrition guidance show about getting vitamins from food, which nutrients may need extra attention, and when fortified foods or supplements can help.
5 min read · Updated Oct 26, 2026

Discover the difference between fat-soluble and water-soluble vitamins, how your body absorbs and stores them, and why both matter for your health.
5 min read · Updated Oct 26, 2026

What vitamin E does, how much you need, the best food sources, how it is absorbed, signs of deficiency, and what to know about supplements and safety.
6 min read · Updated Oct 26, 2026

What water-soluble vitamins are, how the B vitamins and vitamin C differ, their main functions and food sources, and what to know about supplements, deficiency, and safety.
7 min read · Updated Oct 26, 2026

What the 13 essential vitamins are, how fat-soluble and water-soluble vitamins differ, what each vitamin does, key food sources, and when supplements may be useful.
10 min read · Updated Oct 26, 2026

What vitamin A does, how retinol differs from beta-carotene, daily needs, food sources, deficiency signs, supplement safety, and the risks of excessive intake.
8 min read · Updated Oct 26, 2026

Discover what makes vitamins A, D, E, and K different, how your body absorbs them, where to find them in food, and why the right amount matters.
6 min read · Updated Oct 26, 2026

What vitamin K does in the body, how much we need each day, the difference between K1 and K2, and what to know about food sources and supplements.
7 min read · Updated Oct 26, 2026

What research shows about vitamin C, how much we need each day, the best food sources, and its role in immunity, collagen, iron absorption, and colds.
7 min read · Updated Oct 26, 2026

What research shows about vitamin D, how much we need each day, how sunlight and food provide it, and what to know about D2, D3, calcium, and K2.
7 min read · Updated Oct 29, 2026
Vitamins are essential organic nutrients that your body needs in small amounts to support normal growth, metabolism, and overall health. There are 13 essential vitamins, divided into two main groups: fat-soluble vitamins (A, D, E, and K), which can be stored in the body, and water-soluble vitamins (vitamin C and the eight B vitamins), which generally require regular replenishment.
Most vitamins must come from food, although your body can also produce vitamin D when your skin is exposed to sunlight. Explore our guides to learn what each vitamin does, where to find it, how much you need, and when supplementation may be helpful.
What essential vitamins do, where to find them, and how much adults need each day.
| Vitamin | Main role | Food sources | Adult daily need |
|---|---|---|---|
| Vitamin A | Vision, immune function | Carrots, liver, eggs | 700–900 mcg RAE |
| Vitamin B6 | Metabolism, nerve function | Fish, poultry, chickpeas | 1.3–1.7 mg |
| Vitamin B9 (Folate) | DNA synthesis, cell division | Leafy greens, lentils | 400 mcg DFE |
| Vitamin B12 | Nerves, red blood cells | Meat, fish, dairy | 2.4 mcg |
| Vitamin C | Collagen, antioxidant activity | Peppers, kiwi, citrus | 75–90 mg |
| Vitamin D | Calcium absorption, bone health | Fatty fish, fortified foods | 15–20 mcg |
| Vitamin E | Antioxidant protection | Nuts, seeds, oils | 15 mg |
| Vitamin K | Blood clotting, bone health | Kale, spinach, broccoli | 90–120 mcg* |
What each vitamin does and where to get it: the map of the whole topic.
The B vitamins and vitamin C: what they do and why you need them regularly.
What a B-complex covers, and who actually needs one.
Vitamins A, D, E and K: how they are absorbed and why fat matters.
Most people can meet their vitamin needs through a varied diet. Supplements may help when intake is inadequate or specific nutritional needs are higher.
High doses don’t automatically provide extra benefits. Excessive amounts of certain vitamins, particularly vitamins A and D, can be harmful.
Even vitamins that aren’t stored extensively in the body can cause side effects at high doses. Excess vitamin B6, for example, can damage nerves.
The 13 essential vitamins are A, C, D, E, K, and eight B vitamins: B1, B2, B3, B5, B6, B7, B9, and B12. Each plays a different role in supporting normal growth, metabolism, and body function.
Vitamins help your body convert food into energy, maintain healthy tissues, support immune function, and carry out many other essential processes. For example, vitamin A supports vision, vitamin D helps maintain bone health, and vitamin K contributes to normal blood clotting.
Everyone needs adequate amounts of essential vitamins, but not everyone needs daily supplements. A varied diet can provide many of these nutrients. Individual supplementation needs depend on factors such as age, dietary restrictions, pregnancy, and existing health conditions.
Symptoms vary depending on the vitamin involved. Possible signs include fatigue, weakness, changes in vision, or neurological symptoms. These can also have other causes, so symptoms alone cannot confirm a deficiency. A healthcare professional can determine whether testing is appropriate.
Many people can obtain adequate vitamins through a varied diet. However, some individuals may need fortified foods or supplements. For example, people following vegan diets need a reliable source of vitamin B12, while vitamin D needs can depend on dietary intake and other individual factors.
Yes. Excessive amounts of certain vitamins can cause adverse effects. Too much preformed vitamin A can damage the liver, while high doses of vitamin B6 may cause nerve damage. Safety limits vary by vitamin, form, age, and individual circumstances.
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