Vitamin B6, also known as pyridoxine, is one of the eight B vitamins. It is a water-soluble vitamin, meaning the body does not store it in large amounts and excretes any excess through urine. This characteristic requires a consistent supply of Vitamin B6 from dietary sources to maintain sufficient levels for bodily processes.
The Role of Vitamin B6 in the Body
Vitamin B6 functions as a coenzyme, a molecule that helps enzymes carry out their tasks effectively. It is involved in more than 100 different enzyme reactions within the body’s cells, many of which are related to metabolism. These reactions are fundamental for breaking down proteins, carbohydrates, and fats from food, converting them into energy and building blocks the body can use.
The nervous system relies on Vitamin B6 for the creation of neurotransmitters, which are chemical messengers that transmit signals between nerve cells. It aids in the synthesis of serotonin, which helps regulate mood, and dopamine and gamma-aminobutyric acid (GABA), which are also involved in mood and nerve signal transmission.
This vitamin also has a direct role in the formation of hemoglobin. Hemoglobin is the protein within red blood cells responsible for transporting oxygen from the lungs to all other tissues in the body. Without adequate Vitamin B6, hemoglobin production can be impaired, affecting the body’s oxygen-carrying capacity.
The immune system’s ability to respond to infections is also supported by Vitamin B6. It contributes to the health of the immune system by aiding in the production of lymphocytes and T-cells, which are types of immune cells that help protect the body from pathogens.
Recommended Intake and Food Sources
The amount of Vitamin B6 a person needs each day, known as the Recommended Dietary Allowance (RDA), varies based on age and sex. For adults up to 50 years old, the RDA is 1.3 milligrams. Men over 50 require 1.7 milligrams daily, while women in the same age group need 1.5 milligrams per day. Pregnant and lactating women have slightly higher needs.
Vitamin B6 is found in a wide variety of foods, making it accessible in most diets. Animal-based sources are particularly rich in this vitamin, including poultry, fish like tuna, and organ meats such as liver.
For those following plant-based diets, many vegetables, fruits, and legumes are excellent sources. Chickpeas are one of the most concentrated plant-based sources of Vitamin B6. Other valuable sources include potatoes, bananas, and fortified cereals.
Signs of Vitamin B6 Deficiency
A deficiency in Vitamin B6 is not common in the United States, as most people get enough from their diet. Skin-related issues are common, including rashes known as seborrheic dermatitis, cracks at the corners of the mouth (cheilosis), and a swollen, sore tongue (glossitis).
Neurological symptoms can also arise from a lack of Vitamin B6. These may include confusion, irritability, depression, and in severe cases, seizures. A weakened immune system is another potential sign, leading to increased susceptibility to infections. Since Vitamin B6 is involved in red blood cell production, a deficiency can also lead to a specific type of anemia called microcytic anemia.
Certain groups are at a higher risk for developing a Vitamin B6 deficiency. Individuals with kidney disease or conditions that impair nutrient absorption in the small intestine, known as malabsorption syndromes, may not get enough of the vitamin. People with alcohol dependence or certain autoimmune disorders are also more susceptible to deficiency.
Risks of Excessive Vitamin B6 Intake
It is nearly impossible to get too much Vitamin B6 from food sources alone. Toxicity is almost always the result of consuming high-dose supplements over an extended period, which can lead to serious health problems.
The primary risk associated with excessive Vitamin B6 intake is severe nerve damage, a condition called sensory neuropathy. Symptoms of this condition include pain and numbness in the hands and feet. Another significant symptom is a loss of control over bodily movements, a condition known as ataxia.
To prevent these adverse effects, a Tolerable Upper Intake Level (UL) for Vitamin B6 has been established. For adults, the UL is set at 100 milligrams per day from supplements. Other reported side effects of toxicity include painful skin lesions, sensitivity to sunlight, heartburn, and nausea.