13 Essential Vitamins and their Functions

There are several ways to improve your health, and one of the main ones is through your diet. Eating nutritious foods ensures that you have adequate macronutrients (protein, fat, and carb) and micronutrient intakes.

Micronutrients are vitamins and minerals necessary for the body to function properly – in small amounts. Deficiency in specific vitamins can disrupt your metabolism, causing illness and affecting your health as you age.

What are Vitamins?

Before we jump into practice, you must understand the concept of vitamins. Vitamins are necessary substances for the development, growth and functioning of cells.

In total, there are 13 vitamins considered essential – with distinct characteristics and functions – and they can be divided into two types:

Fat-Soluble Vitamins

These are vitamins that are more easily digested by the body when ingested with fat. There are only four fat-soluble vitamins (A, D, E, and K), and they are stored in muscle, fat and liver.

Water-Soluble Vitamins

These vitamins are not stored by the body – except for vitamin B12 –, so you have to consume them regularly to maintain adequate levels. On the other hand, when you ingest them excessively, the surplus is discarded in the form of urine.

There are nine water-soluble vitamins – Vitamin C and all B vitamins.

13 Essential Vitamins: Functions and Sources

It is essential to say that although vitamins are healthy for the body, you should not take them without consulting your doctor or a specialized professional. While most vitamins are not dangerous, overconsumption of certain micronutrients can cause severe illness.

You should also prioritize getting vitamins and minerals through fresh food. No supplement will be as complete and nutritious as a food in its natural form. Consult your doctor before making any decision that could affect your health!

Now, let’s get down to business:

Vitamin A

Vitamin A is stored in the liver until your body needs it. Some of the best sources of Vitamin A are meat (especially liver), fish, and dairy products.

According to the Recommended Dietary Allowances, men between 19 and 50 years old should consume 900 mcg of Vitamin A daily, while the recommendation for women in the same age group is 700 mcg.

It is essential for several physiological processes such as:

Daily replacement of skin cells.
Maintenance of superficial tissues, or epithelia, such as the skin, intestine, bladder, inner ear and eye.
Ensure that specific tissues can produce mucus and protect themselves from infections.
Supports several body systems, such as the immunological.
Helps keep your eyesight healthy in low-light conditions.

Vitamin A Deficiency

The increased risk of serious infections is one of the main consequences of lack of vitamin A. This condition provides a continuous cycle of infections, being one of the known causes of infant mortality.

Vitamin B1 (Thiamine)

Vitamin B-1 is essential for the growth and proper functioning of several cells. As the liver is not capable of storing large amounts, it is important to ingest it daily.

The recommended daily intake is 1.2 mg for 19-year-old men (and older) and 1.1 mg for women of the same age group. Some of the best sources of vitamin B1 are pork, salmon, green peas, and flax seeds.

Vitamin B1 Deficiency

Some of the symptoms of vitamin B1 deficiency are:

Muscle weakness.
Low immunity.
Weight loss.
Confusion and memory loss.

Vitamin B2 (Riboflavin)

Vitamin B-2, or riboflavin, can be consumed by eating vegetables and meat. The body stores small amounts of this micronutrient in the heart, liver and kidneys – while the excess is excreted in the urine.

Some of the best sources of Vitamin B-2 are beef liver, dairy products, breakfast cereals (usually fortified with riboflavin), and beef. The recommended daily consumption is 1.3 mg for men between 19 and 50 years and 1.1 mg for women in the same age group.

Vitamin B2 is essential for specific physiological processes, such as:

Production of energy.
Growth, development and proper functioning of cells.
Metabolism of fats, drugs and steroids.

Deficiency of Vitamin B2

Some of the symptoms of vitamin B2 deficiency are:

Skin diseases.
Hyperemia, or excess blood.
Edema of the mouth and throat.
Lesions and abnormalities in the mouth (such as angular stomatitis and cheilosis).
Loss of hair.
Reproductive problems.

Vitamin B3 (Niacin)

Vitamin B-3, or Niacin, is another essential micronutrient for the body’s physiological processes. Some of the primary sources of vitamin B3 are animal sources such as liver, chicken breast, turkey, and fish (like tuna and salmon).

The recommended daily consumption is 16 mg NE for men over 19 years old and 14 mg NE for women of the same age group.

Some of the main functions of Vitamin B3 are:

Helping various enzymes in the body.
Convert nutrients into energy.
Boost levels of good cholesterol (HDL).
Create and repair DNA.
Exert antioxidant effects.

Deficiency of Vitamin B3

Some of the main symptoms of vitamin B-3 deficiency, or niacin, are:

Depression.
Fatigue.
Headache.
Memory loss.
Hallucinations.

Vitamin B5 (Pantothenic Acid)

Vitamin B-5, or pantothenic acid, is another essential micronutrient, which can be ingested as a food or supplement. Some of the best sources of vitamin B5 are salmon, avocado, chicken breast, among others.

Pantothenic acid is responsible for helping in several physiological processes related to the construction and metabolism of fatty acids, possibly having antioxidant effects and helping to reduce cholesterol. Although there are indications, science has yet to explore this field further.

The recommended daily consumption is 5 mg for men and women over 19 years old.

Vitamin B5 Deficiency

Some of the symptoms of vitamin B-5 deficiency, or pantothenic acid, are:

Fatigue.
Headache.
Disturbed sleep.
Nausea, vomiting and stomach cramps.
muscle cramps
Burning sensation in feet or hands.

Vitamin B6 (Pyridoxine)

Vitamin B-6, or pyridoxine, is a very versatile micronutrient that participates in more than 100 enzymatic reactions in your body, mainly concerning protein metabolism.

Vitamin B6 also influences immune function and participates in the process of cognitive development and maintenance of homocysteine levels – an amino acid that can be nocive in high concentrations.

Some of the best sources of Vitamin B-6 are salmon, tofu and meats in general, such as beef, pork, and chicken breast. The recommended daily intake is 1.3 mg for men and women aged 19 to 50 years.

Deficiency of Vitamin B6

It’s important to mention that people with light vitamin B6 deficiencies may not experience symptoms for months or even years. Pyridoxine deficiency is usually associated with:

Microcytic anaemia.
Dermatitis with cheilosis.
Glossitis.
Depression.
Low immunity.

Vitamin B7 (Biotin)

Vitamin B-7, popularly known as biotin, plays a crucial role in breaking down fats, carbohydrates and proteins.

Although it is commonly marketed as a micronutrient that can help improve skin, nails and hair, there is little scientific evidence to support this theory. The fact is that biotin deficiency can cause hair loss and skin and nail problems, but there are no conclusive studies to indicate that its supplementation can improve these conditions.

This lack of evidence means there is no recommended daily intake but an AI (Adequate Intake) of 30 mg per day for men and women aged 19 and over.

Deficiency of Vitamin B7

Some of the symptoms of biotin deficiency are:

Thinning hair.
Brittle nails
Scaly skin rashes around the mouth, nose, and eyes.

Vitamin B9 (Folate or Folic Acid)

Vitamin B-9, also known as folate or folic acid, can also be consumed in foods and supplements. Some of its primary functions are:

Support protein metabolism.
Help form DNA and RNA.
Helps to break down homocysteine, an amino acid that can have a harmful effect if present in the body in large amounts.
Production of healthy red blood cells.
Fundamental during pregnancy and fetal development.

Some of the best sources of folate are lentils, asparagus and kidney beans. The recommended daily intake is 400 mcg DFE for men and women over 19 years old.

Vitamin B9 Deficiency

Vitamin B9 deficiency is quite rare, as it is present in many foods. Some of the conditions that can increase your risk are bowel surgery, alcoholism, and pregnancy.

Symptoms may include:

Megaloblastic anaemia.
Weakness and fatigue.
Shortness of breath.
Irregular heartbeat.
Hair loss and pale skin.
Mouth sores.

Vitamin B12 (Cyanocobalamin)

Vitamin B-12, or cyanocobalamin, is a micronutrient that helps produce DNA and keeps the body’s blood and nerve cells healthy.

Some of the best sources of Vitamin B12 are clams, beef, sardines, animal liver and kidney. The recommended daily intake for adult men and women is 2.4 mcg.

Vitamin B12 Deficiency

Some of the symptoms of Vitamin B-12 or cyanocobalamin deficiency are:

Tiredness and weakness.
Pale skin.
Heart palpitations.
Loss of appetite and weight loss.
Infertility.
Mental disorders such as depression and dementia.

Vitamin C (Ascorbic Acid)

Vitamin C, or ascorbic acid, is a potent antioxidant essential in infection control and wound healing.

This micronutrient helps your body produce collagen, besides various hormones and chemical messengers that act on the nerves and brain. Vitamin C also plays a vital role in the immune system, stimulating the activity of white blood cells.

Some of the best sources of Vitamin C are oranges, lemons, bell peppers, and broccoli. The recommended daily consumption is 90 mg for men over the age of 19 and 75 mg for women of the same age group.

Vitamin C Deficiency

Some of the symptoms of vitamin C deficiency are:

Scurvy.
Fatigue and malaise.
Delayed healing of skin wounds.
Bleeding or swelling of gums.
Hair loss.
Iron deficiency.

Vitamin D

Vitamin D is an essential micronutrient that helps the body absorb calcium, besides being necessary for healthy muscles and nerves. Vitamin D also supports the immune processes so that your body can eliminate invaders such as viruses and bacteria.

Most foods do not contain Vitamin D naturally, so the most common way to consume it is through fortified foods (such as dairy and breakfast cereals) and supplements. Still, some other sources of Vitamin D are fatty fishes such as trout, salmon and tuna, besides fish liver oil.

Your body can also produce it in short periods of exposure to the sun (about 15 minutes), so you don’t need to overdo it when sunbathing. Avoid the hottest periods of the day, and always use appropriate sunscreen – that suits your skin.

The recommended daily intake for adults between 19 and 70 years old is 15 mcg or 800 IU.

Vitamin D Deficiency

Some of the symptoms of Vitamin D deficiency are:

Rickets (children): a painful disease that weakens and deforms the bones.
Osteomalacia (teens and adults): a disease that causes bone pain and muscle weakness.

Vitamin E

Vitamin E is a powerful antioxidant whose function is to eliminate free radicals that can damage your cells. It also improves your immune system and your heart health.

Some of the best sources of vitamin E are wheat germ oil, sunflower seeds, and almonds. The recommended daily intake is 22 mg for men and women aged 14 and over.

Vitamin E Deficiency

Although Vitamin E deficiency is rare in the U.S., it can develop in people who have digestive disorders or problems with fat absorption.

Some of the symptoms of disability are:

Retinopathy.
Peripheral Neuropathy.
Ataxia.
Decreased immune function.

Vitamin K

Vitamin K is a micronutrient present in different body parts. It helps produce essential proteins for bone development and blood clotting.

Some of the best sources of Vitamin K are kale, spinach, broccoli, and brussels sprouts. Adequate Intake (AI) is estimated at 120 mcg for men aged 19 (and over) and 90 mcg for women of the same age group.

Vitamin K Deficiency

Although Vitamin K deficiency is rare in adults, some of the symptoms are:

Prolonged blood clotting.
Bleeding.
Bleeding.
Osteoporosis or osteopenia.

William Ferrari

Founder and Editor of TheLifesty. Passionate about Health & Fitness and enthusiast about changes. Interested in everything that improves the quality of life.