What is Vitamin B6 Deficiency?
Vitamin B6 is a crucial nutrient found in the cells of all living things. As a water-soluble vitamin, we can find it in various foods such as meat, fish, nuts, beans, grains, fruits, and vegetables. Any multivitamin preparations for adults and children usually include Vitamin B6, and food industries often inject it into processed foods and nutritional powders as a supplement.
With six different natural forms, or “vitamers,” Vitamin B6 exists within mammals. The most common of these are pyridoxine, pyridoxal, and pyridoxamine. These forms vary slightly in their chemical construction. For instance, pyridoxamine is different from pyridoxine and pyridoxal because it contains an extra amine group and a particular type of phosphate ester. The most significant types of vitamin B6 are the active forms called pyridoxal 5’phosphate (PLP) and pyridoxamine 5’phosphate (PMP). Meats mostly contain these ester types, while plants typically contain the less readily absorbed pyridoxine. Multivitamin supplements usually contain pyridoxine.
As a helper molecule, or “coenzyme,” vitamin B6 plays a part in over 100 different enzyme-driven reactions. These include reactions related to carbohydrate, protein, and fat metabolism and are involved in processes that produce glucose and breakdown glycogen. Vitamin B6 is crucial in certain chemical reactions that begin the synthesis of porphyrins and plays a role in cognitive development, affecting neurotransmitter synthesis. It also contributes to immune function through its role in creating interleukin-2 (IL-2) and is vital for making hemoglobin.
Vitamin B6 is also crucial for developing fetuses and is necessary for adequate brain development, which continues into infancy. The recommended daily intake of vitamin B6 varies based on age and life stage, with pregnant and breastfeeding women needing more than others.
What Causes Vitamin B6 Deficiency?
Eating a balanced diet with a variety of foods can help prevent a deficiency in vitamin B6. Foods that are rich in this vitamin include fish, organ meats, poultry, potatoes, grains, fortified cereals, soy products, legumes, and non-citrus fruits.
A deficiency in vitamin B6 often goes hand-in-hand with other vitamin B deficiencies, such as those of folic acid and vitamin B12. People who struggle with alcohol dependence, obesity, and malnutrition due to low protein-energy are among those who are likely to have low levels of active vitamin B6 in their bodies. Expectant mothers, especially those with pregnancy complications like preeclampsia and eclampsia, as well as people with conditions that interfere with nutrient absorption like celiac disease and inflammatory bowel disease are prone to vitamin B12 deficiencies.
Other groups at risk for vitamin B6 deficiency are those who do not consume enough or have increased metabolic requirements, such as people with kidney problems or autoimmune disorders. Those with chronic kidney failure, particularly individuals undergoing blood filtering or fluid replacement treatments, often have low levels of the active form of vitamin B6 in their blood, and may show signs of its deficiency. People with autoimmune diseases like rheumatoid arthritis break down vitamin B6 quickly in their bodies. Both of these groups need a higher daily dosage of vitamin B6.
Certain medications may result in a deficiency in vitamin B6. For instance, tuberculosis patients on medication called isoniazid (INH) may need more vitamin B6, as the drug can block the actions of this vitamin. Penicillamine and levodopa are other drugs that can affect B6 metabolism. Some antiseizure medications, including valproic acid, carbamazepine, and phenytoin, can cause the body to use up B6 faster, leading to a deficiency.
Risk Factors and Frequency for Vitamin B6 Deficiency
According to the Centers For Disease Control (CDC), around 10% of Americans likely have a vitamin B6 deficiency, which makes it one of the most typical nutritional deficiencies. Although overt symptoms are less common than mild deficiencies, it’s still a considerable issue.
People can have low vitamin B6 levels due to various reasons, like consuming less than required, poor absorption in the gut, problems with liver and kidney function, lack of adequate nutrition, and certain drug reactions. Risk groups, particularly those dealing with food scarcity or who live in developing regions, could have a greater likelihood of low dietary intake.
- The body is unable to store vitamin B6 because it’s water-soluble, which means it needs to be consumed every day.
- The body absorbs vitamin B6 more effectively from meat than plants, which may impact those on a wholly plant-based diet. This group might need additional vitamin supplements.
- The form of vitamin B6 often found in multivitamin supplements is pyridoxine hydrochloride.
Signs and Symptoms of Vitamin B6 Deficiency
When a newborn baby experiences seizures, it’s important to look at the mother’s nutrition and the possible presence of a rare genetic disorder that impacts how the body processes the vitamin B6, called pyridoxine. Seizures related to this disorder don’t respond well to regular seizure medications but do respond quickly to a medicine related to vitamin B6. Even though this genetic condition is quite rare, it should always be considered when an infant is having seizures.
Once a child grows beyond infancy, a doctor should consider a range of factors including:
- Initial symptoms the patient presents with
- Past medical conditions and surgeries
- The use of any medicines or supplements
- Dietary habits
There are those who may have slightly low vitamin B6 levels and do not exhibit symptoms. A moderate vitamin B6 deficiency could present a number of symptoms like inflammation and cracking of the lips, changes in mental state, and peripheral neuropathy (a condition affecting the nerves in the extremities). These symptoms may not be unique to a vitamin B6 deficiency, but could also occur due to other medical conditions. A severe deficiency can result in skin disease and anemia.
Past medical history can expose illnesses that may lead to a vitamin B6 deficiency. For instance, conditions that impair nutrient absorption such as inflammatory bowel disease, celiac disease, or surgeries that affect the intestines like weight-loss surgery could potentially cause a vitamin B6 deficiency. Symptoms like feeling weak, changes in mental state, a tingling sensation in the extremities (paresthesias), or skin-related symptoms can suggest a diagnosis.
In a detailed physical examination, a doctor may discover skin conditions, lesions in the mouth’s mucous lining, weakness, motor disorders, and signs of peripheral neuropathy (nerve disease).
Testing for Vitamin B6 Deficiency
If you have a lack of vitamin B6, you may not have clear symptoms, especially in the early stages of deficiency. Some indications, however, can include newly developed sensitivity disturbances, changes to thinking or mood, anemia, skin inflammation in adults, or seizures in infants. If these symptoms are present, it could point to a significant lack of vitamin B6.
To assess your vitamin B6 levels, doctors can measure substances called B6 vitamers in several bodily fluids, such as blood, red blood cells, and urine. The most common way of assessing vitamin B6 status is by measuring the concentration of plasma PLP. This is a direct marker that indicates the amount of vitamin B6 in your liver and is not highly affected by diet change. If your levels are above 30 nmol/l, this is considered normal, 20-30 nmol/l is borderline, and less than 20 nmol/l means you may not have enough vitamin B6. But this test may not be readily available and the results could take some time.
An alternative way of checking your vitamin B6 levels is by measuring how much xanthurenic acid is excreted in the urine after a specific amount of tryptophan is given. Higher levels may mean that you don’t have enough active vitamin B6 needed to process the amino acid tryptophan. Generally, excretion of xanthurenic acid should be less than 65 mmol/day after a 2-gram tryptophan dose. If it’s higher than that, it could suggest abnormal tryptophan processing due to insufficient vitamin B6.
Another test for vitamin B6 status can be measuring erythrocyte transaminase activity. This is a functional test that demonstrates the status of the vitamin B6, and it can be more precise, especially for critically ill patients. If the amount of urinary 4-pyridoxic acid excreted is above 3.0 mmol/day, this could indicate that your short-term vitamin B6 status is adequate.
Treatment Options for Vitamin B6 Deficiency
For people with vitamin B6 deficiency or those suffering from certain diseases, the dosage of this vitamin will depend on their age and how severe their symptoms are. Vitamin B6 can be taken orally or through injections. If a newborn is suspected to have seizures due to a lack of vitamin B6, they should receive 100 mg of the vitamin through an injection. Lifelong treatment is needed for infants diagnosed with this condition. The amount recommended to take each day varies, it can be between 5 to 20 mg per kg of body weight or up to 500 mg each day.
The amount of vitamin B6 a person needs in their diet (often called the recommended dietary allowance or RDA) adjusts as a person gets older. The RDA for children is between 0.5 to 1 mg each day, and up to 1.7 mg for men over 50 and 1.5 mg for women over 50. If a woman is pregnant, the RDA is 1.9 mg, and this increases to 2 mg while breastfeeding. If a person has a deficiency, taking a vitamin B6 supplement and eating a balanced diet can be sufficient treatment. Eating foods like whole grains, vegetables, meat, fish, nuts, and egg yolks can provide enough vitamin B6 for most people. On average, adults eating these types of food can expect to receive about 6 to 10 mg of vitamin B6 daily from their diet, and this is about 75% effective in the body. Yet, note that cooking and food processing techniques can reduce this by 10 to 50%.
For conditions like intense vomiting during pregnancy, taking 25 mg of vitamin B6 three times a day can help improve symptoms. For Premenstrual Dysphoric Disorder, taking between 50 and 100 mg of vitamin B6 can relieve symptoms. This can be more effective when combined with calcium.
It’s important to note that some drugs, like Isoniazid (or INH) used to treat tuberculosis, can cause a vitamin B6 deficiency. People being treated with INH should also take vitamin B6. The suggested dose can be between 6 to 50 mg daily. If a vitamin B6 deficiency develops and causes damage to the nervous system, the dose may need to be between 100 to 200 mg.
If a person has taken too much INH, causing severe seizures, vitamin B6 treatment can be life-saving. The dosage should match the amount of INH a person has taken, up to a maximum of 5 grams. The first dose can be between 1 to 4 grams, given through an injection, followed by 1 gram doses every 30 minutes.
Vitamin B6 can also help in emergencies related to certain types of poisoning. In cases of ethylene glycol poisoning, 50 mg of vitamin B6 aids in converting harmful substances to non-toxic ones. For Gyromitra mushroom poisoning, administering 25 mg/kg of vitamin B6 through an injection can prevent or control seizures.
What else can Vitamin B6 Deficiency be?
When we talk about symptoms caused by Vitamin B6 deficiency, it’s tricky because they can look like many other conditions. For example, mouth sores or inflammation – also known as cheilosis, stomatitis, and glossitis – can also appear with low levels of other vitamins like thiamine and folic acid. Anemia is another condition that needs to be considered, and sometimes a person can have more than one health issue contributing to their symptoms.
Additionally, vitamin B6 deficiency can cause psychiatric symptoms like depression and confusion, but these symptoms could also be caused by entirely different health problems. To get to the bottom of it, doctors need to carefully review the patient’s medical history and carry out a thorough physical examination. Only then can they reach the right conclusion about what might be causing the symptoms.
What to expect with Vitamin B6 Deficiency
A lack of Vitamin B6 can be successfully managed with appropriate intake of pyridoxine, either orally or through an injection. This deficiency can also be prevented by having a diverse diet or taking oral supplements. When Vitamin B6 deficiency is suspected, identified and treated promptly, especially in those with medical conditions that require more than the usual recommended dosage, the outcome is generally excellent.
Possible Complications When Diagnosed with Vitamin B6 Deficiency
Eating foods high in vitamin B6 doesn’t have any known negative effects. However, if you take high doses of vitamin B6 as a supplement, you could end up with permanent damage to your peripheral nerves and sensory nerves.
Preventing Vitamin B6 Deficiency
People with kidney problems, alcohol addiction, difficulty absorbing nutrients, and the elderly have a heightened risk of lacking sufficient vitamin B6. They should be sure to take vitamins appropriate to their age and health status. Those having weight loss surgery might also lack this essential vitamin due to their body not properly absorbing nutrients. Close monitoring is essential for these individuals, as their needs for vitamin B6 may increase.
In wealthier countries like the U.S., the chance of a severe vitamin B6 deficiency is relatively low unless people have a poor diet or chronic illnesses. However, in less wealthy areas worldwide, it’s important to check for a lack of vitamin B6 if people show symptoms like mouth sores, long-term skin rashes, or nerve problems.
Patients taking the drug Isoniazid should be educated on the importance of taking extra vitamin B6 to prevent its deficiency. If these patients show symptoms of deficiency, especially after six months of treatment, they should be tested to ensure their vitamin B6 levels are adequate.