Overview

What is pyridoxine?

Pyridoxine, also known as vitamin B6, is a water-soluble compound. Pyridoxine helps to store the energy that your body extracts from carbohydrates and proteins that you eat. In addition, pyridoxine also has the following important roles:

• Aiding in neurological development: pyridoxine aids in the process of synthesising your brain cells (neurons)
• Aiding in the process of synthesising haemoglobin: Haemoglobin is a very important protein found in the red blood cells, which carries oxygen to all the body cells, tissues and organs. This is essential for your continued survival
• Aiding in immune function: your immune system is essential for your body to defend itself from infection¹

What is pyridoxine deficiency?

Pyridoxine deficiency occurs when your body is not receiving enough pyridoxine.¹ This can occur if you are not receiving enough pyridoxine in your diet, or there may be other causes, known as secondary causes, such as:

• Medications: certain medications that you are taking may cause pyridoxine deficiency
• Pregnancy: being pregnant means that you need more pyridoxine and if your body is not receiving enough this can lead to a deficiency
• Kidney function: having impaired kidney (renal) function
• Liver function: having impaired liver (hepatic) function
• Malabsorption in the gastrointestinal tract: pyridoxine may not be absorbed during digestion in your gastrointestinal tract
• Alcohol: excessively drinking alcohol¹

How common is pyridoxine deficiency?

Your body can not store vitamin B6. Therefore, it is very important that your body is receiving your recommended daily intake of vitamin B6, which is primarily done via your diet. Pyridoxine deficiency affects approximately 10% of those in America, hence why awareness and how to prevent this condition is important.¹

Causes of pyridoxine deficiency

What are the main causes of pyridoxine deficiency? 

Whilst this article has already listed some of the main causes of pyridoxine deficiency in the previous section, this section will delve deeper into some of the other causes.

Dietary insufficiency

The cause of pyridoxine deficiency could be that your diet does not have pyridoxine-rich foods. The following foods are rich in pyridoxine:

• Grains
• Non-citrus fruits, for example, bananas
• Vegetables
• Nuts
• Fish
• Fortified cereals
• Legumes
• Soy products
• Beans, for example, soya beans, chickpeas
• Poultry, for example, chicken and turkey
• Pork
• Some types of fish
• Milk¹

How much pyridoxine do you need dailyThe daily dietary requirements for pyridoxine are as follows, for adults aged 19-64:

• Those assigned female at birth: 1.2 milligrams per day
• Those assigned male at birth: 1.4 milligrams per day

Malabsorption

Gastrointestinal disorders

Pyridoxine deficiency can arise due to malabsorption syndromes, such as the following:

• Crohn’s disease: Crohn’s disease is a chronic inflammation of your gastrointestinal (GI) tract. This inflammation is believed to result in your GI tract having a reduced ability to absorb pyridoxine from your foods when food passes through your GI tract during digestion. This results in pyridoxine deficiency as pyridoxine cannot be adequately extracted and absorbed into your body²
• Ulcerative colitis (UC): UC is a chronic condition where your rectum and colon become inflamed. Similar to Crohn’s disease, the inflammation in the colon and rectum results in a reduced ability to absorb pyridoxine in your gut²
• Coeliac disease: the treatment for coeliac disease involves eating a gluten-free diet, which can be deficient in pyridoxine as you are avoiding eating foods such as grains for example, which contain pyridoxine

Surgery affecting the small intestine

Surgery such as bariatric surgery (weight loss surgery) can affect your small intestine. Your small intestine has the following parts: the duodenum, jejunum and the ileum. At different parts of the small intestine, B vitamins are absorbed. 

However, a type of bariatric surgery, known as a roux-en-Y gastric bypass, causes your food to bypass your small intestine during digestion. In the jejunum, the B vitamin pyridoxine is absorbed from your food. 

However, due to bariatric surgery causing your food to bypass the small intestine, pyridoxine is poorly absorbed from your food, resulting in pyridoxine deficiency.³

Increased requirements

Pregnancy

For those assigned female at birth (AFAB) who are pregnant, and between the ages of 19-50, the recommended daily intake of pyridoxine is 1.9 milligrams, which is a higher recommended dose than for non-pregnant individuals. Due to pregnant individuals needing more pyridoxine, a deficiency can occur  if the mother-to-be does not increase the daily dose of pyridoxine. 

Pyridoxine has been demonstrated in several studies to be important in foetal development and reduces the incidence of pre-eclampsia and preterm birth (birth before the baby has reached full term).⁴

Lactation

Those who are breastfeeding also need an increased amount of pyridoxine, which is approximately 2 milligrams per day. This increased requirement can lead to pyridoxine deficiency if the mother is unaware of how much pyridoxine is needed, and does not increase the daily dose.⁵

Medications

Taking oral contraceptives has been shown to reduce the level of pyridoxine found in your blood plasma.⁶ 

Taking another medication, known as isoniazid, which is used to treat tuberculosis, can also result in pyridoxine deficiency. This in turn can result in neuropathy, where your nerve cells die.⁷  

Symptoms of pyridoxine deficiency

Neurological symptoms

Neurological symptoms include:

• Irritability
• Confusion
• Seizures

Psychiatric symptoms

Psychiatric symptoms include:

• Depression
• Cognitive change

Dermatological symptoms

Dermatological symptoms include:

• Seborrheic dermatitis with cheilosis: where your lips have scaling and there are cracks at the corners of your mouth
• Glossitis: Glossitis is when your tongue is swollen

More symptoms

More symptoms include the following:

• Microcytic anaemia: this type of anaemia occurs when your red blood cells are too small compared to a normal-sized red blood cell⁸
• Your immune system becomes weakened, meaning that you are more susceptible to disease and infection¹

Diagnosis of pyridoxine deficiency

Blood tests for vitamin B6 levels

Blood tests can be conducted, however, blood tests alone cannot confirm the diagnosis of pyridoxine deficiency. 

Review of dietary history and symptoms

Typically,  diagnosis looks at the physical symptoms you present, due to pyridoxine deficiency typically resulting due to a secondary cause, not a lack of pyridoxine in your diet.  

Your response to pyridoxine supplements will also be looked at when coming to a diagnosis. 

Treatment of pyridoxine deficiency

Supplementation

Typically, pyridoxine deficiency is treated with pyridoxine supplements. Usually taking 50-100 milligrams of pyridoxine daily will correct pyridoxine deficiency in adults. These supplements can include the following:

• Multivitamins
• Supplements that contain different B vitamins, including pyridoxine
• A pyridoxine-only supplement

However, please consult with your healthcare provider first, as the cause of your pyridoxine deficiency can impact the treatment you receive. For example, if your deficiency is due to you taking the tuberculosis medication isoniazid, you will be prescribed 30-50 milligrams of pyridoxine daily instead of 50-100 milligrams. 

Prevention of pyridoxine deficiency

Ensuring you have a balanced diet, with foods that are rich in pyridoxine will prevent pyridoxine deficiency. For example, foods rich in pyridoxine include fish, poultry, grains, cereals, non-citrus fruits and potatoes.¹

Summary

• Pyridoxine deficiency, also known as vitamin B6 deficiency is when you are deficient in the vitamin pyridoxine
• Pyridoxine is an important vitamin, aiding in the synthesis of brain cells, metabolism, your immune system’s function, and synthesising haemoglobin which carries oxygen to all your body cells
• Pyridoxine deficiency can be caused by excessive alcohol consumption, not enough pyridoxine in your diet, pregnancy, breastfeeding, taking certain medications, gastrointestinal disorders, disorders of the kidney or liver
• Pyridoxine deficiency can cause microcytic anaemia, depression, irritability, confusion, dermatitis with cheilosis, a weakened immune system and glossitis
• Pyridoxine deficiency is diagnosed using a combination of methods, including looking at the symptoms you are presenting and taking blood tests to measure the pyridoxine levels in your blood plasma
• Pyridoxine deficiency is typically treated with pyridoxine supplements which typically contain 50-100 milligrams of pyridoxine to ensure that enough of this vitamin is being absorbed into your bloodstream
• Ensuring that you are having enough pyridoxine in your diet can aid in preventing pyridoxine deficiency in some instances