Table of contents
1 Common vitamin deficiency symptoms and their potential cause
2 Vitamin A: for eyes and skin
3 Vitamin B1: essential for carbohydrate metabolism
4 Vitamin B2: for skin, brain, hair, blood and nerves
5 Vitamin B3: for your immune system
6 Vitamin B5: for a stable hormone balance
7 Vitamin B6: for the production of red blood cells
8 Vitamin B9: prevents heart disease
9 Vitamin B12: for DNA synthesis
10 Vitamin C: is needed for the production of collagen
11 Vitamin D: strengthens the bones
12 Vitamin E: neutralizes unstable molecules
13 Vitamin K: essential for blood clotting
14 Frequently asked questions about vitamins

If you're looking for ways to improve your quality of life, you've come to the right place! Vitamins are micronutrients that are essential for your well-being. We explain which vitamins are available and where you can get them reliably.

By definition, vitamins are foods that your body needs to carry out various vital functions. All vitamins are essential for your body and, as the name suggests, essential for your everyday vitality. Only vitamin D and vitamin B3 can be produced by your body. Most vitamins must be taken through your diet. In this article, we explain what role vitamins play in your body, how much you should take and how potential deficiency symptoms can manifest themselves.

Common vitamin deficiency symptoms and their potential cause

Symptom Deficiency of
Lack of concentration Vitamin D
Tiredness Vitamin D, Vitamin B12
Rash on areas that are often exposed to the sun Vitamin B3
Slight bruising/ bruises Vitamin K, vitamin C
Dementia Vitamin B1, vitamin B3, vitamin B12
Sensitive bones Vitamin D
Painful, very red or swollen lips Vitamin B2, vitamin B3, vitamin B6
Inflammation of the tongue Vitamin B2, vitamin C
Abnormal tingling or numbness Vitamin B1
Joint swelling or pain Vitamin C
Cognitive deficits Vitamin B1, vitamin B3, vitamin B6, vitamin B12
Impaired night vision Vitamin A
Clouding of the cornea/blurred vision Vitamin A
Numbness Vitamin B1, vitamin B12
Frequent bleeding gums or tooth loss Vitamin C

Vitamin A: for eyes and skin

Vitamin A produces the pigments in our eye retina. In addition to the eyes, vitamin A is essential for the health of the skin. The recommended daily intake for adults is approx. 1.0 mg for men and 0.8 mg per day for women.1

What vitamin deficiency symptoms can occur with vitamin A?

Vitamin A deficiency is the leading cause of preventable blindness in children. A lack of vitamin A can cause the following symptoms:

  • Xerophthalmia: dry, thickened conjunctiva and cornea
  • Night blindness
  • Keratinized growths (metaplasia) on the conjunctiva that lead to blurred vision2

Natural sources of vitamin A

  • Sweet potatoes (961 μg/ 100 g)
  • Carrots (852 μg/ 100 g)
  • Tuna (757 μg/ 100 g)
  • Pumpkin (558 μg/ 100 g)
  • Spinach (524 μg/ 100 g)
  • Honeydew melon (169 μg/ 100 g)

Vitamin B1: Essential for carbohydrate metabolism

Vitamin B1 is particularly important for carbohydrate metabolism.3 It helps to break down and release energy from food. It is therefore indirectly extremely important for the general health of the skin, hair, muscles, brain and nerves.4 The need for vitamin B1 decreases slightly with age. The recommended daily intake of vitamin B1 for adults is between 1.1 and 1.3 mg/day.5

What vitamin B1 deficiency symptoms can occur?

Vitamin B1 deficiency leads to beriberi disease, which is particularly common among alcoholics. It leads to peripheral neuropathy. People with this disease have impaired sensory, motor and reflex functions.6

Natural sources of vitamin B1

  • Both fresh and dried fruits
  • Linseed (1.6mg/100g)
  • Salmon (0.3mg/100g)
  • Peas (0.3mg/100g)
  • Tofu (0.2mg/100g)
  • Brown rice (0.2mg/100g)7

Vitamin B2: for skin, brain, hair, blood and nerves

Similar to B1, B2 is extremely important for the health of the skin, brain, hair, blood and nerves, as it also plays an important role in our body's energy metabolism. Men need about 1.3-1.4 mg, women about 1.0-1.1 mg, and pregnant women about 1.3-1.4 mg of vitamin B2 per day.8

What vitamin B2 deficiency symptoms can occur?

Vitamin B2 deficiency is extremely rare, but the consequences can be varied and serious. In addition to insufficient intake, endocrine abnormalities (such as thyroid hormone deficiency) and various diseases can be caused by vitamin B2 deficiency.9 Signs and symptoms of vitamin B2 deficiency include skin disorders, hyperemia and edema of the mouth and throat, torn corners of the mouth, cheilosis (swollen, cracked lips), hair loss, sexual problems, sore throat, itchy and red eyes, and liver and nerve damage.[10,11]

Natural sources of vitamin B2

  • Almonds (1.1mg/100g)
  • Salmon (0.5mg/100g)
  • Mushrooms (0.5mg/100g)
  • Spinach (0.5mg/100g)
  • Eggs (0.5mg/100g)

Vitamin B3: for your immune system

Vitamin B3 is very important for the energy utilization of our food and for the health of our skin, blood cells and brain. It plays a central role in the function of the nerves and liver.12 In adults, the daily requirement of vitamin B3 decreases slightly with age. Men need approx. 14-16 mg per day, women approx. 11-13 mg per day and pregnant/breastfeeding women approx. 14-16 mg per day.13

What vitamin deficiency symptoms can occur?

Severe vitamin B3 deficiency leads to a condition called pellagra. Pellagra causes a skin rash or brown discoloration when skin has been exposed to sunlight. The skin also develops a rough, sunburn-like appearance14 In addition, pellagra can cause a noticeably red tongue and changes in the digestive tract leading to vomiting, constipation or diarrhea. Neurological complaints of pellagra include depression, apathy, headaches, fatigue, memory loss that can lead to aggressive behavior, and visual hallucinations.15

Natural sources of vitamin B3

  • Tuna (22.1mg/100g)
  • Peanuts (14.4mg/100g)
  • Chicken breast (9.5mg/100g)
  • Portobello mushrooms (6.3mg/100g)
  • Brown rice (2.6mg/100g)

Vitamin B5: for a stable hormone balance

Vitamin B5 is not only important for energy metabolism, like other B vitamins, but also helps in the production of neurotransmitters, steroid hormones, fatty acids and haemoglobin. Adolescents and adult men and women require 6 mg of vitamin B5 per day from the age of 14.16

What vitamin B5 deficiency symptoms can occur?

As vitamin B5 is found in almost all foods, a deficiency is rare, except in people with severe malnutrition.17 When someone suffers from a vitamin B5 deficiency, it is usually accompanied by a deficiency of other nutrients, so it is difficult to identify the effects specific to a vitamin B5 deficiency. Vitamin B5 deficiency occurs almost exclusively in individuals who were taking vitamin B5 metabolic antagonists18

Natural sources of vitamin B5

  • Sunflower seeds (7 mg/ 100g)
  • Shiitake mushrooms (3.6 mg/ 100g)
  • Salmon (1.9 mg/ 100g)
  • Avocados (1.4 mg/ 100g)
  • Sweet potatoes (0.5 mg/ 100g)

Vitamin B6: for the production of red blood cells

Vitamin B6 helps to regulate homocysteine levels (blood levels of the amino acid homocysteine) and can reduce the risk of heart disease. It supports the conversion of tryptophan into niacin and serotonin, a neurotransmitter that plays a central role in sleep, appetite and mood. Vitamin B6 helps in the formation of red blood cells and influences cognitive abilities and immune function.19 Adult men have a daily requirement of 1.6 mg of vitamin B6 per day. Women 1.4 mg per day or 1.5-1.8 mg per day if pregnant or breastfeeding20

What vitamin B6 deficiency symptoms can occur?

An isolated deficiency of vitamin B6 is extremely rare and is usually associated with low concentrations of other B-complex vitamins, such as vitamin B12. A vitamin B6 deficiency causes biochemical changes that become more and more obvious as the deficiency progresses.

Vitamin B6 deficiency is associated with anemia, dermatitis with cheilosis (scaling of the lips and cracks at the corners of the mouth) and glossitis (swollen tongue), depression and confusion, and a weakened immune system. People with a mild deficiency may have no deficiency signs or symptoms for months or even years. In infants, vitamin B6 deficiency leads to irritability, abnormal hearing loss and convulsive seizures.21 End-stage renal disease, chronic renal insufficiency and other kidney diseases can also cause vitamin B6 deficiency.22

Natural sources of vitamin B6

  • Salmon (0.9 mg/100g)
  • Tofu (0.5 mg/ 100g)
  • Bananas (0.4 mg/ 100g)
  • Potatoes (0.3 mg/ 100g)
  • Sweet potatoes (0.2 mg/ 100g)

Vitamin B9: prevents heart disease

Vitamin B9 is essential for the production of red blood cells, can lower homocysteine levels (blood levels of the amino acid homocysteine) and thus reduce the risk of heart disease. It helps prevent birth defects of the brain and spine when taken early in pregnancy. Adult men and women need about 300 µg of vitamin B9 per day. Breastfeeding women approx. 450 µg and pregnant women approx. 550 µg per day.23

What vitamin B9 deficiency symptoms can occur?

Isolated vitamin B9 deficiency is uncommon and usually coexists with other nutrient deficiencies, as it is closely associated with poor nutrition, alcoholism and malabsorptive disorders. Megaloblastic anemia, characterized by large, abnormal blood cells, is the primary clinical sign of vitamin B9 deficiency.25 Symptoms include fatigue, feelings of weakness, difficulty concentrating, irritability, headaches, palpitations and shortness of breath.26Vitamin B9 deficiency can cause pain on the tongue and oral mucosa, changes in skin, hair or fingernail pigmentation, and increased homocysteine concentrations in the blood.27

Natural sources of vitamin B9

  • Soybeans (311 μg/ 100 g)
  • Lentils (181 μg/ 100 g)
  • Asparagus (149 μg/ 100 g)
  • Spinach (146 μg/ 100 g)
  • Broccoli (108 μg/ 100 g)

Vitamin B12: for DNA synthesis

Vitamin B12 supports the reduction of homocysteine levels (blood levels of the amino acid homocysteine) and can therefore reduce the risk of heart disease, just like vitamin B9. It contributes to the formation of red blood cells and DNA. Vitamin B12 helps with the formation of new cells, the breakdown of some fatty acids and promotes the growth of nerve cells.28 The daily requirement for vitamin B12 for adult men and women is approx. 4.0 µg per day. Pregnant women need approx. 4.5 µg and breastfeeding women approx. 5.5 µg.29

What happens with vitamin B12 deficiency

Vitamin B12 deficiency is characterized by fatigue, general weakness, anemia, loss of appetite and weight loss.30 Neurological problems, such as numbness and tingling in the hands and feet, can occur31 Other symptoms of vitamin B12 deficiency include depression, confusion, balance problems, dementia, poor memory and pain in the mouth or on the tongue. The neurological symptoms of vitamin B12 deficiency can also occur without anemia, which is why early diagnosis and intervention is important to avoid incurable damage.32

Natural sources of vitamin B12

  • Mussels (98.9 μg/ 100 g)
  • Tuna (10.9 μg/ 100 g)
  • Beef (7.5 μg/ 100 g)
  • Eggs (1.1 μg/ 100 g)
  • Milk (0.5 μg/ 100 g)

Vitamin C: is required for the production of collagen

Our body needs vitamin C to form collagen33, a connective tissue that is needed to heal wounds and supports the blood vessel walls. Vitamin C helps in the formation of neurotransmitters (noradrenaline and serotonin). It is also an antioxidant and neutralizes unstable molecules that can damage cells and thus cause cancer34 Adult men need approx. 110 mg, women 95 mg, pregnant women 105 mg and breastfeeding women 125 mg of vitamin C per day.35

What vitamin C deficiency symptoms can occur?

An acute vitamin C deficiency develops relatively quickly compared to other nutrient deficiencies. Vitamin C deficiency leads to scurvy36 The time course of scurvy formation varies greatly, but the first signs can already appear within a month.37

Initial symptoms may include fatigue, malaise and inflammation of the gums38 As vitamin C deficiency progresses, collagen synthesis is disrupted and connective tissue is weakened, leading to petechiae, joint pain, poor wound healing or hyperkeratosis.39 Other signs of scurvy include depression as well as swollen, bleeding gums and loosening or loss of teeth due to tissue fragility and capillary weakness (due to the lack of collagen).40

Natural sources of vitamin C

  • Guava (228 mg/ 100 g)
  • Paprika (128 mg/ 100 g)
  • Kiwi (93 mg/ 100 g)
  • Strawberries (59 mg/ 100 g)
  • Oranges (53 mg/ 100 g)

Vitamin D: strengthens the bones

Vitamin D helps to stabilize normal calcium and phosphorus levels in the blood, which strengthens bones. It also supports the formation of teeth and bones. Vitamin D can be synthesized naturally in the body if you are regularly exposed to the sun. If an adult gets hardly any sunlight in their daily life, they should take about 20 µg per day in the form of a dietary supplement.41

These are the typical vitamin D deficiency symptoms

Rickets and osteomalacia are the classic vitamin D deficiency diseases. In children, vitamin D deficiency causes rickets, a disease characterized by a lack of mineralization of bone tissue, resulting in soft bones and skeletal deformities.42

In adults, vitamin D deficiency can lead to osteomalacia, which results in bone weakness. Symptoms of bone pain and muscle weakness may indicate inadequate vitamin D levels, but such symptoms may be subtle and go undetected in the early stages.43

Natural sources of vitamin D

  • Salmon (16.7 μg/ 100 g)
  • Mushrooms (that have been in the sun) (31.9 μg/ 100 g)

Vitamin E: neutralizes unstable molecules

Vitamin E is an antioxidant that neutralizes unstable molecules that can damage cells. It also protects vitamin A and fatty acids from damage. The need for vitamin E decreases with age. Adult men need about 12-15 mg per day and women about 11-12 mg per day.44

What vitamin E deficiency symptoms can occur?

As the digestive tract needs fat to absorb vitamin E, people with fat absorption disorders are more likely to have a deficiency than people without such disorders.45 Vitamin E deficiency symptoms include retinopathy, peripheral neuropathy, skeletal muscle myopathy, ataxia, and immune system impairment.46

Natural sources of vitamin E

  • Sunflower seeds (26.1 mg/ 100 g)
  • Almonds (25.6 mg/ 100 g)
  • Avocados (2.1 mg/ 100 g)
  • Spinach (2.1 mg/ 100 g)
  • Butternut squash (1.3 mg/ 100 g)

Vitamin K: essential for blood clotting

Vitamin K activates various proteins and calcium and is therefore particularly essential for blood clotting. The recommended daily dose of vitamin K for adult men is approx. 70-80 µg per day. An adult woman needs approx. 60-65 µg per day and approx. 60 µg per day if she is breastfeeding or pregnant.47

What vitamin deficiency symptoms can occur?

Bleeding is the classic sign of vitamin K deficiency, although these effects only occur in severe cases. Because vitamin K is needed for the carboxylation of osteocalcin in bone, vitamin K deficiency can reduce bone mineralization, contributing to osteoporosis or an overall reduction in bone density.48

Natural sources of vitamin K

  • Cabbage (419 μg/ 100 g)
  • Broccoli (141 μg/ 100 g)
  • Cabbage sprouts (140 μg/ 100 g)
  • Asparagus (51 μg/ 100 g)
  • Kiwi (40 μg/ 100 g)

Frequently asked questions about vitamins

Which vitamins are lacking in fatigue?

Vitamin B12, C and D deficiencies can cause tiredness. However, as vitamin C deficiency is very rare in developed countries, you should keep an eye on your vitamin B12 and vitamin D levels in particular. Vitamin B12 deficiency inhibits the production of red blood cells, which impair oxygen transport in the body.49 This makes you feel tired or sluggish. Even a small deficiency of vitamin D can lead to fatigue and a general feeling of poor well-being.50

Which vitamins am I missing?

You may find our symptom table may help you to find out which vitamin deficiency you could be suffering from. Nevertheless, you should always discuss any suspicious symptoms or complaints with your doctor. He or she can check for a suspected deficiency by means of a blood test.

Which vitamin deficiency causes dry skin?

One of the best-known symptoms of a vitamin D deficiency is dry skin. Vitamin D is particularly important for the health of your skin as it stimulates receptors that are responsible for the formation of the skin barrier, which is essential for protecting the skin.51

What are the symptoms of vitamin B deficiency?

There are many different B vitamins that fulfill different functions in the body. It is important not to pigeonhole them all, as deficiencies of these different vitamin B variations can lead to different symptoms. Our symptom table should give you a good overview.

What do vitamins do in the body?

Vitamins enable a wide variety of functions in our body. Without vitamins, our body would not be able to perform vital tasks such as converting food into energy, building and maintaining bones, teeth, muscles, skin, blood and hair, as well as maintaining the functionality of our brain, eyes, nervous and immune systems.

Which vitamins for listlessness?

A deficiency of many different vitamins and minerals can lead both directly and indirectly to listlessness. The lack of motivation is often accompanied by tiredness and concentration problems. A lack of B vitamins, vitamin D or the minerals iron and magnesium can cause listlessness particularly quickly.52

Which vitamins to take together Table?

To provide your body with the best conditions for efficient absorption of nutrients into the blood, you should consider taking the following nutrients in combination. Some nutrients complement or interfere with each other's function in your body - so depending on what and when you eat, you may gain or miss out on the benefits of these healthy foods (and supplements).

Calcium and vitamin D
Most of the ingested calcium in our bodies is stored in our bones and vitamin D helps with the absorption, transportation and deposition of this calcium in our bones.53

Vitamin D and healthy fatty acids
Vitamin D is one of the fat-soluble vitamins. This means that it must be mixed with fat in order to be absorbed by the body. It is therefore advisable to combine vitamin D-rich foods with a high-quality fat such as olive oil, linseed, avocado, fish, chia seeds or nuts.54

Iron and vitamin C (especially for vegetarians)
Iron can be obtained from plant and animal foods. Although plant foods contain a lot of iron, it can often only be absorbed to a limited extent due to other substances - such as oxalic acid in spinach. Vitamin C compensates for this absorption-inhibiting effect as it promotes iron absorption.55

Wie merkt man dass man Vitaminmangel hat?

Symptome eines Vitaminmangels können sehr vielfältig sein und hängen vom jeweiligen Vitamin ab. Häufige Anzeichen sind Müdigkeit, Konzentrationsschwäche, Infektanfälligkeit, trockene Haut, brüchige Nägel und Haare, Muskelschwäche oder Stimmungsschwankungen. Da diese Symptome auch bei anderen Erkrankungen auftreten können, ist bei Verdacht auf einen Vitaminmangel eine ärztliche Abklärung mit einem Bluttest ratsam.

Welcher Vitaminmangel ist am häufigsten?

In Deutschland ist laut nationaler Verzehrsstudie eine unzureichende Versorgung mit Vitamin D am weitesten verbreitet, vor allem in den Wintermonaten. Da Vitamin D hauptsächlich durch Sonnenbestrahlung der Haut gebildet wird, haben viele Menschen einen Mangel, wenn sie sich zu wenig im Freien aufhalten. Auch Folsäure, Jod und Eisen zählen zu den kritischen Nährstoffen, bei denen häufig eine Unterversorgung besteht.

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