What are four examples of vitamins? Your essential guide

December 23, 2025 •

4 min read

Over 500,000 children globally suffer from eye conditions due to vitamin A deficiency alone. This highlights the critical role these micronutrients play in our bodies. In this guide, we will explore what are four examples of vitamins that are crucial for your body's daily functions, immune system, and overall wellness.

Quick Summary

This article outlines four essential vitamins—A, D, C, and B12—detailing their primary functions, key food sources, and the crucial roles they play in maintaining human health, from vision to nerve function.

Key Points

Vitamin A for Vision: Vitamin A is vital for good vision, especially in low light, and is found in carrots, sweet potatoes, and leafy greens.
Vitamin D for Bones: The 'sunshine vitamin' aids calcium absorption for strong bones and is made by the skin through sun exposure.
Vitamin C for Immunity: A powerful antioxidant, Vitamin C boosts the immune system, promotes collagen production for healthy skin, and aids wound healing.
Vitamin B12 for Nerves: Critical for healthy nerve function, DNA synthesis, and red blood cell production, Vitamin B12 is mainly found in animal products.
Fat vs. Water-Soluble: Fat-soluble vitamins (A, D) are stored in the body, while water-soluble vitamins (C, B12) are not and require regular consumption,.
Balanced Diet is Key: A diverse diet is the most effective way to get essential vitamins, with supplements serving as an option under medical guidance.

What Are Vitamins and Why Do We Need Them?

Vitamins are organic compounds that your body needs in small amounts for a variety of metabolic processes, growth, and development. Since our bodies cannot produce most vitamins in sufficient quantities, they must be obtained through our diet. Vitamins are broadly categorized into two groups based on how they are absorbed and stored in the body: fat-soluble and water-soluble. Fat-soluble vitamins, including A, D, E, and K, dissolve in fat and are stored in the liver and fatty tissues. Water-soluble vitamins, such as the B-complex and C, dissolve in water and are not stored in the body for long, so they must be consumed regularly.

Vitamin A: Vision and Immune Support

Often referred to as retinol, vitamin A is a fat-soluble vitamin with several critical functions. It is well-known for its role in producing the pigments in the retina, which is essential for good vision, particularly in low light. It also helps maintain healthy skin, mucous membranes, and supports a robust immune system. The body can get vitamin A from two sources: preformed retinol from animal products and provitamin A carotenoids, like beta-carotene, from plants.

Sources of Vitamin A:

Retinol: Liver, eggs, fortified milk, and cheese.
Beta-Carotene: Carrots, sweet potatoes, spinach, and leafy greens.

Vitamin D: The Sunshine Vitamin for Bone Health

Vitamin D is unique because your body can produce it when your skin is exposed to sunlight. It is a fat-soluble vitamin primarily responsible for helping the body absorb and regulate calcium and phosphorus, which are vital for building and maintaining strong, healthy bones. A deficiency can lead to soft bones (osteomalacia) in adults and rickets in children. Beyond bone health, vitamin D also supports muscle strength and immune function,.

Sources of Vitamin D:

Sunlight: Exposure to sunlight on the skin.
Foods: Fatty fish (salmon, tuna), fish liver oils (cod liver oil), fortified dairy products, and fortified cereals,.

Vitamin C: The Powerful Antioxidant

Vitamin C, or ascorbic acid, is a water-soluble antioxidant that protects cells from damage caused by free radicals. Its functions are widespread throughout the body and include promoting healthy skin, blood vessels, bones, and cartilage. It is also essential for wound healing and boosts the immune system, helping white blood cells fight infections. Furthermore, vitamin C significantly enhances the absorption of non-heme iron (the iron found in plant-based foods).

Sources of Vitamin C:

Fruits: Oranges, strawberries, kiwi, papayas, and cantaloupe.
Vegetables: Broccoli, bell peppers, kale, Brussels sprouts, and potatoes.

Vitamin B12: Nerves and Red Blood Cells

As part of the B-complex group, Vitamin B12 (cobalamin) is a water-soluble vitamin that plays a vital role in keeping your body's blood and nerve cells healthy. It is crucial for the formation of DNA during cell division and helps prevent megaloblastic anemia, a condition that can make people feel tired and weak. Unlike other B vitamins, B12 can be stored in the liver for several years, though regular intake is still necessary. Because B12 is not naturally found in plant foods, vegans and vegetarians often need to rely on fortified foods or supplements.

Sources of Vitamin B12:

Animal Products: Meat, fish, poultry, eggs, and milk.
Fortified Foods: Breakfast cereals, nutritional yeast, and plant-based milks.

Comparing Fat-Soluble and Water-Soluble Vitamins

Understanding the key differences between vitamin types is important for proper absorption and intake. This table highlights how fat-soluble vitamins (like A and D) differ from water-soluble vitamins (like C and B12),.


Feature	Fat-Soluble Vitamins (A, D, E, K)	Water-Soluble Vitamins (C, B-complex)
Absorption	Absorbed with dietary fat in the small intestine.	Dissolve in water and are absorbed directly into the bloodstream.
Storage in Body	Stored in the liver and fatty tissues.	Not stored in the body (except B12); excess is excreted via urine.
Requirement	Do not need to be consumed daily; stored reserves can last for months.	Need to be consumed regularly, preferably daily, to prevent deficiency.
Risk of Toxicity	Higher risk of toxicity due to accumulation from excessive intake.	Lower risk of toxicity as excess is typically flushed out of the body.

Conclusion: A Balanced Approach to Vitamin Intake

Obtaining adequate amounts of essential vitamins is fundamental for good health. Vitamins A, D, C, and B12 represent just a few of the crucial micronutrients that enable our bodies to function optimally, from building strong bones to supporting our immune system. The most effective way to ensure a balanced intake is to consume a varied diet rich in fruits, vegetables, whole grains, and lean proteins. For those with dietary restrictions or specific health concerns, supplements can be beneficial, but it's always best to consult with a healthcare professional before starting any new regimen. Remember, your body's complex needs are best met through a holistic approach to nutrition.

Learn more about vitamins from MedlinePlus here.

Frequently Asked Questions

The primary difference lies in how they are stored and absorbed by the body. Fat-soluble vitamins (A, D, E, K) are absorbed with fat and stored in the body's tissues, while water-soluble vitamins (B-complex, C) are not stored and must be regularly replenished,.

Vitamin D is known as the 'sunshine vitamin' because the human body produces it naturally when the skin is exposed to sunlight. This is a major source of the vitamin for many people.

Yes, vegans and vegetarians must pay close attention to their vitamin intake, especially for Vitamin B12, which is naturally found almost exclusively in animal products. Fortified foods and supplements are often necessary.

For most healthy individuals, a balanced and varied diet provides all the necessary vitamins. Supplements are typically recommended only for those with deficiencies, certain medical conditions, or specific dietary restrictions, and should be taken under a doctor's supervision.

Excess intake of fat-soluble vitamins (A, D, E, K) poses a higher risk of toxicity because they can accumulate in the body's fat stores. Acute or chronic over-supplementation of Vitamin A, for instance, can cause serious illness.

A deficiency in vitamin B12 can lead to megaloblastic anemia, causing symptoms such as fatigue and weakness. It can also result in nerve damage, leading to numbness or tingling in the hands and feet.

Vitamin C significantly enhances the absorption of non-heme iron, which is the type of iron found in plant-based foods. Including vitamin C-rich foods with iron sources can help increase the body's iron uptake.