Signs of a vitamin deficiency vary by the vitamin and severity of the deficiency. Symptoms can occur in the neurological, cardiovascular, and gastrointestinal systems.

Vitamins help the body grow and ensure its systems function correctly. However, inadequate intake or the ability of the body to absorb vitamins may lead to a deficiency. This can result in a host of symptoms that vary in severity.

This article looks at common vitamins and deficiencies, signs and symptoms of each deficiency, diagnosis, treatment, and when to contact a doctor about deficiencies.

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There are 13 essential vitamins:

The Centers for Disease Control and Prevention (CDC) conducts a bi-yearly, cross-sectional study of the U.S. population called the National Health and Nutrition Examination Survey (NHANES).

According to 2020 research citing NHANES results, the following percentages of people had deficiencies in key vitamins:

  • 45% for vitamin A
  • 46% for vitamin C
  • 95% for vitamin D
  • 84% for vitamin E

The specific symptoms a person experiences may depend on which vitamin(s) are at inadequate levels.

Signs of a vitamin A deficiency

According to a 2022 review, vitamin A deficiency is relatively common in developing countries. It is the primary cause of eye diseases.

Clinical symptoms of vitamin A deficiency may include:

  • xerophthalmia, which results in dry eye
  • Bitot spots, which cause dried conjunctiva on the eye
  • night blindness
  • keratomalacia (cornea cloudiness) and permanent blindness

The presence of other conditions may raise the risk of vitamin A deficiency, such as:

People should discuss any symptoms they experience with a doctor to determine the possible cause.

Read more about vitamin A deficiency.

Symptoms of a vitamin B deficiency

Deficiencies in various B vitamins may have overlapping and differing signs and symptoms.

Thiamine (B1) deficiency

The initial symptoms of B1 deficiency may include:

Thiamine deficiency may affect the cardiovascular, nervous, and immune systems, such as:

With prolonged deficiency, people may experience:

Riboflavin (B2) deficiency

Riboflavin deficiency may include the following signs and symptoms:

Niacin (B3) deficiency

Niacin deficiency results in a condition called pellagra. It causes various symptoms, but the most common are:

The condition may affect people’s neurological, gastrointestinal, and integumentary (skin) systems.

Neurological and psychiatric symptoms may include:

Dementia and delirium may occur as pellagra advances.

Gastrointestinal symptoms may include:

Possible skin effects include:

  • Skin burning sensation: Sun-exposed areas may develop rash-like areas of skin burning on both sides of the body.
  • Malar rash: Also known as a butterfly rash, this can occur on the hands, feet, and neck.

Pantothenic acid (B5) deficiency

According to the National Institutes of Health (NIH), pantothenic acid deficiency is very rare in the United States.

Severe deficiency may cause:

B6 deficiency

Common signs and symptoms of moderate deficiency include:

Severe deficiency may result in seborrheic dermatitis and anemia.

However, since these symptoms may also occur in other health conditions, it can be challenging for healthcare professionals to diagnose vitamin B6 deficiency.

Biotin (B7) deficiency

Biotin deficiency leads to a range of signs and symptoms, including neurological and skin changes. Neurological symptoms may include:

Intestinal symptoms may also develop, such as:

  • nausea
  • vomiting
  • appetite loss

Other biotin deficiency effects include ketoacidosis, lactic acidosis, and organic aciduria.

Learn more about biotin deficiency.

Vitamin B9 (folate) deficiency

A deficiency in vitamin B9 can cause various issues, including:

  • weakness
  • fatigue
  • difficulty concentrating
  • heart palpitations
  • headache
  • shortness of breath
  • soreness and ulcers on the tongue
  • GI symptoms
  • changes in hair and nail pigmentation

B12 deficiency

People can develop B12 deficiency through a lack of B12 in the diet, a condition called pernicious anemia, or when taking certain medications.

Symptoms include:

  • fatigue
  • heart palpitations
  • pale skin
  • weight loss
  • numbness and tingling in the extremities

Learn more about B12 deficiency.

Signs of a vitamin C deficiency

Common signs of vitamin C deficiency may include:

  • gingivitis (inflammation of the gums) with bleeding
  • periodontal (gum) disease
  • tooth loss
  • mucocutaneous petechiae
  • ecchymoses, or bleeding into the skin
  • hyperkeratosis, or skin thickening
  • alopecia, also known as hair loss
  • corkscrew hairs, which are twisted or coiled hair shafts resulting from impaired collagen production
  • swan neck hairs, which are hair shafts that bend at multiple points due to weakened hair follicles
  • perifollicular hemorrhages, which is bleeding from the tissues surrounding hair follicles
  • nail-related changes, such as koilonychia (spoon-shaped nails) and splinter hemorrhages (red streaks under the nails)

If someone experiences any of the above symptoms, it is important to consult a doctor. A doctor can determine whether the symptoms are from a vitamin C deficiency or other condition.

Inadequate vitamin C intake is also called scurvy. It is a rare condition but reversible with prompt treatment. Signs and symptoms of scurvy may include the previously listed symptoms as well as the following:

Signs of a vitamin D deficiency

Most people with vitamin D deficiency do not have symptoms. However, mild and chronic deficiency may lead to:

A prolonged and severe vitamin D deficiency may cause:

Children with a vitamin D deficiency may experience:

If a caregiver notices any of these symptoms in a child, they should consult a doctor for prompt diagnosis and treatment.

Learn more about vitamin D deficiency.

Signs of a vitamin E deficiency

Possible symptoms of a vitamin E deficiency include:

  • ataxia
  • difficulty with upward gaze
  • hyporeflexia, which is the loss of skeletal muscle reflexes

Severe symptoms include:

Less common symptoms include muscle weakness and visual-field constriction.

Find out more about the signs of a vitamin E deficiency.

Signs of a vitamin K deficiency

The absence of vitamin K may contribute to:

  • bleeding disorders
  • impaired bone development
  • cardiovascular diseases

Vitamin K deficiency may cause bleeding at venipuncture sites. This is where a person gets blood drawn.

Newborn babies with low vitamin K levels who do not receive prompt treatment are at risk of vitamin K deficiency bleeding, which causes excessive bleeding.

People should speak with a medical professional if they notice any of these symptoms. A doctor can help prevent any possible complications of vitamin K deficiency.

Learn more about vitamin K deficiency.

Because vitamin deficiency symptoms may overlap with other conditions, it is important to get an accurate diagnosis from a doctor and not self-diagnose.

To make a diagnosis of a vitamin deficiency, a doctor takes into account a person’s signs and symptoms during a physical exam. In most cases, they will order a blood test to measure vitamin levels in a person’s blood.

Not all vitamin levels can be easily tested in routine clinical settings. In some cases, a doctor may refer a person to a specialist.

If a person has any of the symptoms described above, it is a good idea to contact a doctor.

Left untreated, some deficiencies can cause long-term complications. Prompt diagnosis and treatment can help prevent serious effects.

Signs and symptoms of a vitamin deficiency vary by the vitamin and severity of the deficiency. A number of these symptoms may overlap with other conditions, so it is important a person receives an accurate diagnosis from a medical professional.

Common signs and symptoms of all deficiencies affect the neurological, cardiovascular, and gastrointestinal systems. People may also experience symptoms affecting their eyes, skin, brain, and oral health.

The usual line of treatment for vitamin deficiencies may include daily supplementation. The type of treatment differs depending on individual circumstances.