What is vitamin B6?
There is no one vitamin B6. Rather, vitamin B6 or pyridoxine is a collective term for three chemical compounds: pyridoxine, pyridoxal and pyridoxamine. All compounds occur naturally and can be metabolically converted into the other form.
Pyridoxal phosphate and pyridoxamine phosphate are also assigned to vitamin B6 as active forms of the chemical compounds. Since vitamin B6 is used in orthomolecular medicine primarily in the form of pyridoxine and pyridoxine hydrochloride, vitamin B6 is therefore generally referred to as pyridoxine.
Vitamin B6 effect
In the form of pyridoxal-5-phosphate, vitamin B6 plays a crucial role in the metabolism as a coenzyme of different enzymes. Pyridoxal-5-phosphate is particularly active in protein and amino acid metabolism. It is involved in the conversion of amino acids and causes the production of so-called biogenic amines. These include neurotransmitters (messengers) such as dopamine, serotonin or γ-aminobutyric acid.
The formation of myelin, the covering of the nerve cells, and the production of important components of the cell membrane also depend to a certain extent on an adequate supply of vitamin B6.
The vitamin is also involved in the formation of the red blood pigment hemoglobin. Hemoglobin not only gives blood its red color, it also transports oxygen and carbon dioxide in the blood.
Vitamin B6 also serves to break down the amino acid homocysteine, which is known in connection with the hardening of the arteries (arteriosclerosis), heart attack and stroke.
For some time now, it has also become apparent that the body needs the vitamin for immune defense. Recent test results showed that vitamin B6 didn't just carry out a coenzyme function. Rather, it is suspected that it acts directly on the receptor, e.g. the binding site, of steroid hormones.
Steroid hormones include sex hormones such as estrogen, progesterone and testosterone, but also glucocorticoids such as the stress hormone cortisol. As a result, the vitamin can significantly influence the active properties of the hormones.
So in summary, vitamin B6 is important for:
- the amino acid metabolism
- the production of neurotransmitters
- the formation of the red blood pigment hemoglobin
- the regulation of the immune system
- the function of the hormonal system
- the fat metabolism and growth
Vitamin B6 deficiency
In contrast to a vitamin B12 deficiency, which is estimated to affect up to 33 percent of the population depending on age and gender, a vitamin B6 deficiency is much less common.
The National Consumption Study II from 2008 shows that 12 percent of men and 13 percent of women do not achieve the recommended daily intake of this vitamin. Generally speaking, a lack of vitamin B6 (which includes the compounds pyridoxine, pyridoxal and pyridoxamine) is not shown separately, but in connection with other vitamin B deficiency diseases.
Vitamin B6 deficiency - who is particularly at risk?
Sub-optimal B6 values are especially found in risk groups such as:
- Underweight people
- Older people who do not eat enough food
- People on a radical diet
- People with high alcohol consumption or alcohol abuse
- People suffering from an autoimmune disease or chronic inflammation
Pregnant as well as breastfeeding women and patients with kidney diseases such as a renal insufficiency or chronic uremia are also at a higher risk of deficiency due to an increased vitamin requirement. It is also important to note that certain medicines can increase the need for vitamin B6.
Therefore, patients taking hydrazide-containing tuberculostatic agents, phenytoin, D-penicillamine or L-dopa should pay more attention to their diets so that they do not suffer from a B6 deficiency.
This is how a vitamin B6 deficiency indicates itself
The organism's storage capacity for vitamin B6 is between 4 and 6 weeks. Even a slight lack of the vital substance can result in serious symptoms. As with the other B vitamins, a deficiency in B6 is primarily noticeable through a loss of vitality.
Just like with a vitamin B12 deficiency, a so-called angular cheilitis can also occur with a B6 deficiency. These are small and quite painful tears in the corners of the mouth. Wounds or ulcers can also occur in the oral cavity.
People with a vitamin B6 deficiency can suffer from diarrhea, loss of appetite, vomiting and anemia. However, the deficiency symptoms particularly often affect the nervous system.
In the event of a severe deficiency, the peripheral nerves can degenerate, so that the movement sequences of the body can no longer be controlled properly. Paralysis and other disorders of movement coordination (ataxia) occur. Other neurological disorders that can appear as deficiency symptoms include:
Vitamin B6 dosage
The recommended daily intake of vitamin B6 is provided by the DGE as 1.2 to 1.6 mg. The values fluctuate depending on gender and age. Daily protein intake and the presence of chronic underlying diseases also play a role in the calculation of the dosage.
With a low pyridoxine diet and symptoms that indicate a vitamin B6 deficiency, a substitution with a daily dose of 5 to 25 mg is recommended for at least 3 weeks. A maintenance dose of around 3 mg can be taken daily.
A vitamin B6 substitution of 50 to 300 mg per day can also be useful for the prophylaxis of drug-related deficiency symptoms while taking medications such as isoniazid, cycloserine, theophylline or hydralazine.
For the prevention of cardiovascular diseases, the D-A-CH-Liga homocysteine recommends a supplementation of around 25 mg per day even with slightly increased homocysteine levels in the blood.
Daily Vitamin B6 requirement
According to the DGE (German Nutrition Society), the daily intake of the following amounts of vitamin B6 is necessary to prevent a deficiency.
- Infants 0 to under 4 months: 0.1 mg
- Infants 4 to under 12 months: 0.3 mg
- Children 1 to under 4 years: 0.4 mg
- Children 4 to under 7 years: 0.5 mg
- Children 7 to under 10 years: 0.7 mg
- Children 10 to under 13 years: 1.0 mg
- Children 13 to under 15 years: 1.4 mg
- Adults 15 to under 19 years: 1.2 to 1.6 mg
- Adults 19 to under 65 years: 1.2 to 1.5 mg
- Adults 65 years and older: 1.2 to 1.4 mg
- Pregnant women from the 4th month: 1.9 mg
- Breastfeeding women: 1.9 mg
Interpretation of the guidelines
The recommendations of the German Nutrition Society are primarily aimed at healthy people. The daily requirement is calculated so that a healthy person does not develop a vitamin B6 deficiency.
As a coenzyme, B6 is involved in many metabolic processes and plays a role in managing inflammation, among other things. Accordingly, people who suffer from a chronic or acute inflammation have an increased need for vitamin B6.
It should also be noted that the body only has a small amount of the vital substances ingested from food. Vitamin B6 is mainly absorbed in the small intestine and especially in the empty intestine (jejunum). In a healthy person, the intake rate is 70 to 75 percent.
If there are bad settlements or inflammation in the small intestine, the uptake rate may decrease. Some of the vitamin is also produced by intestinal bacteria to increase the amount of pyridoxine available. Diseases of the gastrointestinal tract counteract this B6 synthesis, which significantly increases the need for vitamin B6 from food.
Vitamin B6 overdose
Vitamins are vital for the human body. They support various bodily functions and are part of the essential metabolic processes. But when taking vitamin preparations, the motto 'a lot helps a lot' does not apply. An overdose of vital substances can lead to unwanted side effects. Is an overdose possible even when taking vitamin B6 and how can you recognize this?
Overdose only when taking large amounts
Symptoms of an overdose of vitamins only appear when vitamin B6 is taken in higher doses over a period of 12 to 40 months. With long-term intake of 1000 mg to 6000 mg vitamin B6, neurological disorders can occur.
These show themselves above all through movement coordination disorders (ataxia). People affected by this move uncoordinated and suffer from excess movements. Skin discomfort such as ant walking or numbness in the extremities can also occur.
Other symptoms of an overdose are painful skin lesions and stomach and intestinal complaints such as nausea, diarrhea or heartburn. To safely avoid overdosing, the Food and Nutrition Board (FNB) recommends not adding more than 100 mg of vitamin B6 per day.
Vitamin B6 for vegans and vegetarians
Around 75 million people worldwide are on a vegetarian diet and do not eat meat or meat products. More and more people are also deciding to go vegan. The reasons for this are diverse. The decision to forego meat and other animal products can be culturally, ethically or financially justified.
A diet without animal products can also make sense from a health perspective. The vegetarian or vegan lifestyle can reduce the risk of typical diseases of civilization such as diabetes mellitus or arteriosclerosis.
A balanced vegetarian or vegan diet usually fully covers the need for nutrients and vital substances such as minerals, trace elements and vitamins. The only exception is vitamin B12, which has to be added to a vegan diet through food supplements or fortified foods. In contrast to vitamin B12, vitamin B6 can be found in plant foods as well as in foods of animal origin.
Plant based vitamin B6 sources
Good plant based vitamin B6 sources are starchy vegetables such as potatoes and various fruits. The plant based vitamin sources hardly rank behind the animal counterparts in regards to the B6 content.
For example, while a serving of beef liver contains about 0.9 mg of B6, a serving of chickpeas has a B6 content of about 1.1 mg. In addition to this, vitamin B6, which is found in plants, is relatively heat-stable.
Animal foods in particular lose vitamin B6 when they are heated up. A vegetarian or vegan diet is therefore not a risk factor for a vitamin B6 deficiency.
Vitamin B6 and PMS
In the days before menstruation, many women suffer from physical and psychological problems. This is called premenstrual syndrome or PMS. In addition to pain and fatigue, typical PMS symptoms are water retention and a depressive mood.
It is estimated that every third woman of childbearing age has PMS complaints. Various studies provide evidence that the additional intake of vitamin B6 can counteract with these symptoms.
Although the general symptoms are reduced, the intake of pyridoxine hydrochloride and other B6-containing food supplements has a particularly significant influence on the mood swings that can occur as part of the PMS.
The vitamin has a considerable share in the production of the neurotransmitters serotonin and dopamine. Among other things, these are responsible for psychological and mental well-being.
By influencing the messenger metabolism, vitamin B6 can presumably raise and/or stabilize the mood before and during menstruation.
Especially when magnesium and vitamin B6 are combined for a period of at least 2 months, there is a significant effect with regard to symptoms such as depression, mood swings, tiredness and irritability.
Vitamin B6 and insomnia
Sleeplessness, also called insomnia, is always characterized by too little sleep. Those affected have problems falling asleep and/or wake up several times during the night and stay awake.
Likewise, tingling legs (restless legs) or snoring can disturb their sleep. The hormone melatonin plays a crucial role in the sleep-wake regulation. It is produced in the pineal gland in the brain from the neurotransmitter serotonin. In addition to serotonin and melatonin, the messenger substance dopamine is involved in the sleep process.
Vitamin B6 deficiency can lead to sleep disorders
In its active form P5P, vitamin B6 is involved in the synthesis of neurotransmitters such as dopamine and serotonin. The messenger substance serotonin is formed from the amino acid tryptophan.
The body needs folic acid to convert tryptophan into the serotonin precursor 5-hydroxy-tryptophan (5-HTP). Vitamin B6 is necessary for 5-HTP to produce serotonin.
The conversion of the amino acid L-3,4-dihydroxyphenylalanine (L-DOPA) into dopamine can only be done using vitamin B6. An adequate supply of vitamin B6 therefore contributes to a balanced neurotransmitter household. Dopamine, serotonin and melatonin are necessary for falling asleep, facilitate the transition to deep sleep and reduce waking up at night.
Vitamin B6 and Restless Legs Syndrome
2 to 10 percent of the population suffer from the so-called Restless Legs Syndrome (RLS). It is a neurological disease that is characterized by an urge to move around and an abnormal sensation in the legs.
Typically, these symptoms occur primarily in rest situations and are accordingly a common cause of sleep disorders. The entire group of B vitamins, also vitamin B6, play a crucial role in the functioning of the nervous system and can therefore alleviate the symptoms of the disease.
Experts also suspect that Restless Legs Syndrome (in part) is caused by a disorder in the dopamine metabolism. Therefore, so-called dopamine agonists are used to treat the disease, which act like the neurotransmitter dopamine on the receptors.
Vitamin B6 can be helpful to stimulate dopamine synthesis. Especially people who have to take the medication lurasidone due to a bipolar disorder can benefit from an additional B6 intake. Lurasidone is an atypical neuroleptic that is a common side effect of RLS.
Vitamin B6 and depression
Depression is a multifaceted clinical symptom. The causes and triggers of the mental illness are still unclear. In addition to psycho-social aspects such as past traumatic experiences or chronic stress, neurobiological aspects such as an imbalance in neurotransmitters in certain brain regions or a lack of micronutrients are also repeatedly discussed.
The link between homocysteine, depression and vitamin B6
In various studies, there was a distinct association between an elevated level of homocysteine in the blood and the appearance of depression symptoms. Homocysteine is a naturally occurring amino acid that is created as an intermediate product in the so-called methionine metabolism.
If there is too much homocysteine in the blood, this promotes the development of various diseases. In addition to folic acid and vitamin B12, vitamin B6 plays a crucial role in lowering homocysteine levels. With the help of vitamin B6, homocysteine can be converted into the much more harmless amino acid cysteine. With the intake of vitamin B12, folic acid and vitamin B6, the homocysteine level can be significantly reduced.
Via the neurotransmitter household, vitamin B6 is heavily involved in regulating mood and also memory. This is one reason why the vitamin is used as a therapeutic aid in the treatment of depression. Vitamin B6 contributes to the production of the neurotransmitters serotonin, norepinephrine and dopamine, among other things.
A vitamin B6 deficiency can lead to disturbances in the neurotransmitter household and thus to significant functional restrictions in nerve function. This way, an insufficient supply of vitamin B6 can contribute to the development of neurological and psychological disorders such as depression.
The study also suggests that vitamin B6 can support therapy with antidepressants. The antidepressants not only work faster with additional intake of vitamin B6, B12 and folic acid, there are also fewer relapses.
Contradictory study results?
There is always evidence of a positive effect of vitamin B6 on depressive moods, but not all studies can confirm this. For example, a study from 2016 showed that vitamin B6 prevented depression, especially in women.
In men, a high vitamin B12 level was more protective. However, the positive effect of vitamin B6 on depression in women couldn't be confirmed in various studies on postpartum depression.
In summary, it can be said that the actual importance of vitamin B6 in the development of depression has not yet been fully proven. However, the studies indicate that dietary supplements with vitamin B6 or also vitamin B12 and folic acid may be suitable as a supportive treatment and to prevent mental illnesses.
Vitamin B6 - Dementia and Alzheimer's
Dementia is a neurological disease that is characterized by the progressive loss of mental abilities. Dementia mainly affects people older than 65 years of age. The best known and most common form is Alzheimer's dementia (AD), which is also known as Alzheimer's disease.
Around 1.6 million people with dementia live in Germany, 2/3 of them are diagnosed with Alzheimer's. 300,000 new cases occur each year - due to demographic change, this number is expected to increase further.
How does Alzheimer's disease develop?
With Alzheimer's disease, there is a slowly progressive loss of nerve cells in the brain. The areas that are responsible for memory, language and orientation are especially affected.
The 2 proteins ß-amyloid and tau, which clump together to form so-called plaque, play a major role in the loss of the nerve substance. The failure of the nerve cells also affects the signal transmission in the still healthy brain tissue. The reasons for this are a lack of production of the transmitter acetylcholine and the excessive release of the messenger glutamate.
It is believed that dementia in general and Alzheimer's in particular are caused by both genetic and epigenetic factors. In addition to omega fatty acids and vitamins B12, B9, C, A and D, vitamin B6 is also assigned to factors that can reduce the risk of dementia.
Can vitamin B6 help with dementia and Alzheimer's?
Various studies with older people and people with dementia show that taking vitamin B6, mostly in combination with vitamin B12 and folic acid, can alleviate the symptoms of the neurodegenerative disease.
B vitamins can reduce the amount of ß-amyloids in the blood, which are the main constituent of senile plaques and thus also the main cause of Alzheimer's disease and other dementia diseases.
Taking 20 mg of vitamin B6 per day (in combination with 0.5 mg of vitamin B12 and 0.8 mg of folic acid) showed positive effects on cognitive abilities in one study. The supply of vital substances slowed the breakdown of the brain substance (atrophy) and thus improved memory performance.
With her study, Douaud et al. was also able to show that the supplementation of B vitamins can slow the dementia-typical atrophy of the gray mass of the brain.
Epilepsy and vitamin B6
The term epilepsy includes various neurological diseases with a diverse range of symptoms. Basically, it is epilepsy when repeated epileptic seizures occur in a patient.
0.5 to 1 percent of the population suffer from epilepsy - making the disease one of the more common neurological disorders. An epileptic seizure is a spontaneous discharge of nerve cells or nerve cell assemblies in the central nervous system that occur in seizures.
In the nervous system, there is an imbalance between the effects of the neurotransmitters GABA and glutamate. This increases irritability and reduces the seizure threshold.
Vitamin B6 dependent epilepsy
Epilepsy dependent on vitamin B6 is also known as pyridoxine-dependent epilepsy or PDE for short. It is characterized by seizures, which occur in babies just a few hours after birth.
In some cases, the baby can even suffer from seizures in the womb. Newborns also show neurological abnormalities between the individual attacks. The cause of this are congenital defects in the vitamin B6 metabolism or congenital defects that are associated with an inactivation of the vitamin.
If epilepsy is suspected of being vitamin B6-dependent, patients receive 50 to 100 mg of pyridoxine injected into the vein. The symptoms improved significantly in 85 percent of the newborns. Patients with PDE have to substitute vitamin B6 all their lives.
Interactions between B vitamins and epilepsy
In patients with epilepsy, there are often deficits in the vitamin balance. For example, epileptics usually have a poor supply of vitamin B12; in men, the vitamin B6 level is also noticeable.
One reason for this deficiency condition is the medication that patients take against epilepsy. Valproate, in particular, can negatively affect the supply of vital substances when taken for a long time. For long-term epileptics, the vitamin level should therefore be checked at regular intervals.
Vitamin B6, homocysteine and epilepsy
In animal experiments, the researchers succeeded in provoking epileptic seizures in rats with an injection of homocysteine. Homocysteine and other sulfur-containing metabolites such as homocysteic acid are apparently able to stimulate the so-called NMDA receptors.
If these glutamate receptors are overstimulated, an epileptic attack can be triggered. Homocysteine also reduces the availability of the substance adenosine, which acts as an anticonvulsant in the organism, e.g. as protection against tonic-clonic seizures.
Because antiepileptic drugs can significantly affect both folate, B12 and B6 metabolism, epileptics often have elevated homocysteine levels in their blood. These can be reduced by taking vitamin B6, B12 and folic acid. A vitamin B6 therapy can therefore relieve epileptic seizures not only in vitamin B6-dependent epilepsy, but also in other forms of the neurological disease.
Vitamin B6 and cancer
In the European Union, cancer is the second leading cause of death directly after cardiovascular diseases. Around 1/5 of all deaths are attributable to cancer. Every year, 2.5 million people in Europe fall ill to this disease.
The reasons for this are diverse. For example, toxins such as those found in cigarettes can significantly increase the risk of cancer. WHO estimates that up to 30 percent of all cancers can be attributed to an improper and unbalanced diet. In gastrointestinal tract cancer, the proportion is as high as 70 percent.
Can vitamin B6 reduce the risk of cancer?
A large-scale study from 2017 with 27,853 participants over the age of 45 examined the relationship between the intake of B vitamins through food and dietary supplements and the risk of breast cancer. Adequate intake via food and dietary supplements correlated significantly with a lower risk of breast cancer.
In other studies, higher serum levels of the vitamin in the blood correlated with a lower risk of lung cancer. There also appears to be a significant connection between vitamin B6 and colorectal cancer.
However, it seems to make a difference which form of the vitamin is added. In a study from 2018, Matsuo et al. examined the effect of vitamin B6 on the growth and proliferation of melanoma cells.
Malignant melanoma is a malignant tumor of the skin's pigment cells. The study showed that vitamin B6 in the form of pyridoxal could slow cell growth and proliferation. In contrast, the growth-inhibiting effect of vitamin B6 in the form of pyridoxine was rather weak.
Damage to DNA due to a lack of nutrients?
A possible explanation for the connection between a vitamin B6 deficiency and an increased risk of cancer can be found in the statements by molecular biologist and professor of biochemistry Bruce Ames. He researched the effect of micronutrients on human DNA and found that a lack of nutrients such as vitamin B6, vitamin B12, folic acid or vitamin C leads to DNA damage.
If there is a lack of nutrients, the chromosomes are more unstable and tend to break. The effect of vitamin and mineral deficiency on DNA is even comparable to the damaging effects of radioactivity and various cancer-causing chemicals.
Vitamin B6 as a risk factor for lung cancer?
An Ohio State University study opposes the above described positive study results. Researchers evaluated data from more than 77,000 men and women and examined the relationship between taking supplements and cancer risk.
It was shown that the intake of vitamin B6 and vitamin B12 in men led to an almost double risk of lung cancer. Smokers even had an almost three-fold risk when taking vitamin B6 as a single preparation. This effect could not be demonstrated in women.
However, the results of the study are not without controversy. Firstly, the increased risk only applies to doses of more than 20 mg vitamin B6 per day over a period of 10 years. On the other hand, the researchers in this study only relied on the test persons' statements, but did not verify them. It is therefore unclear how much vitamin B6 the study participants actually consumed.
So far, no concrete connection between vitamin B6 and cancer has been scientifically proven, but there are numerous indications that a good supply of vitamin B6 can have a protective effect. It is therefore advisable to ensure a sufficient vitamin B6 level.
Vitamin B6 in pregnancy, lactation and child development
The supply of B vitamins is particularly important during pregnancy. The need for vitamin B6 is slightly increased during pregnancy and breastfeeding. According to the recommendations of the DGE, pregnant and lactating women should consume around 1.9 mg of vitamin B6 daily.
Pyridoxine not only supports the metabolism of the unborn child in the conversion of fats, carbohydrates and proteins, but also plays a role in the development of the brain, the nervous system and the production of red blood cells (erythrocytes).
Vitamin B6 against morning sickness
Especially in the first 3 months of pregnancy, many women suffer from nausea and vomiting. The feeling of being unwell and nausea appear increasingly in the morning and are often perceived as extremely stressful.
In a review from 2016, researchers summarized medication for the treatment of nausea during pregnancy and evaluated their effectiveness. There were indications that ginger and vitamin B6 can alleviate the unpleasant morning sickness.
In case of mild to moderate morning sickness, a B6 substitution with a dosage of 3 times 10 mg to 3 times 25 mg per day is recommended in consultation with the treating gynecologist.
Danger to the unborn through vitamin B6?
There is some evidence in the scientific literature that taking vitamin B6 in the first few months of pregnancy can lead to birth defects in the unborn child. However, more extensive research suggests that taking 100 mg of vitamin B6 per day in the first few months of pregnancy does not adversely affect the health of the unborn child or the birth weight.
Embryotox, the pharmacovigilance and advice center for embryonic toxicology of the Charité-Universitätsmedizin Berlin, only recommends a substitution with vitamin B6 during pregnancy if there are actually therapeutic indications, such as a treatment with isoniazid or neuropathic pain.
According to Embryotox, a daily dose of 80 mg should not be exceeded permanently for the treatment of nausea during pregnancy. It should always be kept in mind that due to active placental transport, the concentrations in the unborn child are approximately twice as high as in the mother.
Vitamin B6 can disrupt milk production
The results of some studies suggest that higher doses of vitamin B6 (200 to 600 mg daily) can disrupt milk production. However, an overview study from 2017 does not confirm this connection. Seven studies were examined with a total of 1,155 participants, 271 of whom were taking pyridoxine.
Only 2 studies showed a connection between the intake of vitamin B6 and a reduced milk production. The other studies were unable to demonstrate any lactation-inhibiting effects of the vitamin. With a usual dose of up to 20 mg per day, no effects on milk production are likely to be expected.
Vitamin B6 in foods
Vitamin B6 is one of the vital substances that is ubiquitous. This means that they are found in almost every animal and plant based food. While pyridoxine is primarily a component of plant based foods, pyridoxal, pyridoxamine and the associated phosphoric acid esters are found particularly in foods of animal origin.
Vitamin B6 occurrence in food (given in mg per 100 g)
- Chicken: 0.50
- Beef: 0.50
- Beef: 0.50
- Pork liver: 0.59
Milk, dairy products and egg
- Buttermilk: 0.04
- Yogurt: 0.05
- Quark: 0.08
- Egg: 0.12
- Cucumber: 0.04
- Asparagus: 0.06
- Savoy cabbage: 0.20
- Lamb's lettuce: 0.25
- Potatoes: 0.30
- Carrots: 0.30
- Brussels sprouts: 0.30
- Halibut: 0.42
- Sardine: 0.97
- Lobster: 1.18
- Salmon: 0.98
- Oatmeal: 0.16
- White bread: 0.02
- Brown rice: 0.28
- Bran: 0.73
- White beans: 0.41
- Peas: 0.12
- Chickpeas: 0.54
- Lentils: 0.60
- Soybeans: 1.00
While the B6 from plants is relatively heat-stable, the cooking losses for the vital substance from animal foods are up to 45 percent. When sterilizing milk, you can expect a vitamin loss of around 40 percent.
It should also be noted that pyridoxal, pyridoxamine and the phosphoric acid esters are extremely sensitive to UV light. The vitamin B6 content in a clear glass bottle of milk that is exposed to sunlight is reduced by half within a few hours.
Even with careful handling of the food and proper storage, a loss of around 20 percent must be taken into account. A healthy diet with sufficient fruit and vegetables and a balanced composition of meals with various ingredients usually still covers the recommended daily requirement.
Side effects of vitamin B6
No side effects are expected if the appropriate dosage regulations are observed. Long-term use of tablets or capsules in too high a dose may cause nausea, vomiting and neurological symptoms. In individual cases, the skin's sensitivity to light is increased. High doses of vitamin B6 can lead to increased sleepiness, shortness of breath and apathy in infants.
Vitamin B6 interactions
Vitamin B6 interacts with various medications that affect the vitamin B6 levels.
Interactions with the medication Cycloserine
The broad-spectrum antibiotic Cycloserine, which is primarily used to treat tuberculosis, is associated with an increased excretion of vitamin B6 via the kidney. It is believed that the loss of the vitamin through the kidney is at least partially responsible for the neurotoxicity of the drug. Substituting vitamin B6 while taking the antibiotic can counteract side effects.
Vitamin B6 and anti-epileptics
Medications for epilepsy with the active ingredients valproate, carbamazepine and phenytoin can lower the vitamin B6 level in the blood and at the same time increase the homocysteine level. This significantly increases the risk of seizures for epileptics.
Theophylline and Vitamin B6
Theophylline is an active ingredient from the group of anti-asthmatics, which is used to treat bronchial asthma and COPD (chronic obstructive pulmonary disease). Patients treated with theophylline medication have a lower concentration of vitamin B6 in the blood. This can lead to neurological disorders when taking medication.
Vitamin B6 and oral contraceptives
Approximately 6 million women in Germany regularly take the contraceptive pill. Depending on the preparation, the hormone preparations contain various combinations of estrogens and progestogens. Various studies indicate that contraceptives for women lead to deficits in micronutrients.
In addition to vitamin B6, vitamins B2, B12, C, magnesium and zinc are particularly affected. It is believed that the loss of B6 is due to an increased consumption of B6-dependent enzymes. The low B6 values may also be based on an acute inflammatory process that is triggered by the pill.
For example, women who take oral contraceptives often have elevated levels of inflammation in the blood. The estrogen-induced B6 deficiency can lead to disorders in the neurotransmitter metabolism and negatively affect the function of the central nervous system. This can manifest itself as depression, nervousness or irritability. All 3 symptoms are common side effects of oral contraceptives.
A randomized, placebo-controlled intervention study by Fäth-Neubauer et al. demonstrated that nutritional supplementation can subjectively improve the quality of life of women who take the pill. This self-assessment of women could actually be demonstrated with a measurable improvement in vitamin and serotonin status.
Interactions and synergy effects with other vitamins and nutrients
Vitamin B6 reacts and interacts with a variety of nutrients and vital substances. For optimal utilization of the individual vitamin, it is advisable to add nutrient combinations. The absorption and the effect of the individual substances can often be improved this way.
Vitamin B6, vitamin B12 and folic acid
Both vitamin B6, vitamin B12 and folic acid are involved in the so-called one-carbon metabolism. This C1 metabolism involves various biochemical reactions in which chemical compounds with a single carbon atom are transferred.
The organism needs the 3 vitamins to deactivate the harmful homocysteine and thus prevent nervous system disorders and cardiovascular diseases. While the vitamin B12 makes homocysteine harmless for the time being through direct methylation, the folic acid ensures that this condition is preserved.
Vitamin B6 also contributes to a conversion into a harmless form of the amino acid. So that the C1 metabolism works smoothly, the interaction of all 3 vitamins is necessary. Similar synergy effects are evident when vitamin B6 is combined with other B vitamins such as vitamin B3 (niacin) and vitamin B7 (biotin).
Vitamin B6 and magnesium
Magnesium is one of the essential minerals and must therefore be supplied to the body from the outside. The mineral is involved in cell division, nerve function and muscle contraction. Bone build-up and regulation of the heart activity is also closely related to the magnesium supply.
A magnesium deficiency can lead to muscle cramps, depression, fatigue, dizziness or irregular heartbeat. For an improved absorption of magnesium from the intestine into the blood and into the body cells, it is advisable to take the mineral in combination with vitamin B6.
Vitamin B6 test
If you suspect a vitamin B6 deficiency, it is advisable to have the vitamin level in the blood tested. People who are at an increased risk of a vitamin B6 deficiency should also have the vitamin levels checked at regular intervals.
How is vitamin B6 tested?
In order to assess the supply of vitamin B6, the pyridoxal phosphate content in the blood is determined. The reference values vary depending on the laboratory. In addition to the blood test, a urine test can also be performed. The substance cystathionin in the urine is measured as a marker for a B6 deficiency.
The formation and breakdown of cystathionin is catalyzed by enzymes that require vitamin B6 as a cofactor. An increase in cystathionine in the urine can thus be seen as a clear indication of a functional vitamin B6 deficiency.