Vitamin B6 is an essential, water-soluble vitamin which, like other B vitamins is necessary for numerous metabolic processes. Vitamin B6 plays a serious role in the metabolism of proteins and carbohydrates, in cell division and in the proper functioning of the nervous system. (2) Beside that, it’s important for the formation of dopamine and serotonin hormones so a severe deficiency may even cause depression. (3) 

It can be found in many natural foods so deficiency rarely occurs when following a balanced diet. For therapeutic purposes large dose vitamin B6 is used to treat several illnesses, for example PMS (premenstrual syndrome). (4, 5) In time, large doses can cause neuropathic disorders so daily intake should be maximized at 25 mg, just to be on the safe side. (6) 

How much vitamin B6 do we need? 

Necessary daily intake for adults is determined between 1,5-2 mg while for children lower than that, in proportion to body weight. A varied, natural diet provides about 10 mg vitamin B6 but its absorption can be hindered by numerous diseases. (1) To avoid overdosing a maximum daily intake of 100 mg has been specified, but in fact it has no further positive effect above 25 mg so it’s not worth substituting more than that. (1) 

How is it utilized in the body? 

While every form of vitamin B6 can be found in different plants, foods of animal origin mainly contain it in the form of phosphoester. To achieve absorption – like the other B vitamins – first each form has to degrade so they can be utilized, in the case of B6 it means pyridoxin, pyridoxal or pyridoxamine. In the end, active PNP and PLP coenzymes are formed from them in the body, within the cells and they are responsible for most functions of B6. (6) 

It’s true for vitamin B6 as well that several diseases can impair its absorption but with adequate concentration utilization is possible through passive transport. However, this only happens in the case of pyridoxin, pyridoxal and pyridoxamine forms. (7) 

What’s the richest source? 

Many foods contain vitamin B6 but chickpeas, salmon, tuna, potatoes and bananas are regarded as outstanding sources. (1) Most vegetables, fruit and grains contain an acceptable amount, and grains are often enriched with B vitamins as well. 

A lot of dietary supplements contain vitamin B6: it can be found in many multivitamins and B-complex products, and it’s also distributed as an individual product or combined with magnesium. These contain vitamin B6 mainly in pyridoxin form, less frequently as PLP. 

What does it help protect you from? 

In the case of vitamin B6 deficiency the production of several vital hormones, such as dopamine, serotonin or growth hormone can become insufficient. (8, 9) In time this can lead to mood changes or in more severe cases, depression. In a study, low vitamin B6 status intensified the symptoms of depression. (3) 

Presumably vitamin B6 deficiency may lead to increased cancer risk. Women with the highest vitamin B6 levels demonstrated significantly lower breast cancer risk, although further research didn’t find vitamin B6 supplementation effective. (10) (11) A similar result was found concerning colon cancer: based on a meta-analysis the risk of the disease decresed by 50% among those with the highest vitamin B6 levels. (12) 

Based on the findings of several studies vitamin B6 supplementation can abate the symptoms of premenstrual syndrome but it may be effective especially for those with vitamin B6 deficiency. (4, 5) It’s important to note that long term large doses’ neuropathy-inducing effects are emphasized in these studies as well, so do not exceed the maximum daily intake. 

It’s worth mentioning vitamin B6’s effect on the homocystein level: vitamin B6 deficiency can increase homocystein levels which probably explains that among low vitamin B6 level patients the risk of cardiovascular disease is twice as high. (13) (14) 

Fun fact 

Vitamin B6 is one of those rare vitamins whose too high intake must be avoided because it could even cause a permanent damage of the nervous system. It is particularly important not just to avoid deficiency but also to beware of overdosing. Negative effects have been verified in the case of 100 mg or higher daily doses but it’s easily possible that less than that is also problematic. Many badly created B-complex products used to simply contain a daily 100 mg of each B vitamin, including B6, luckily it’s increasingly rare. 

[The cover photo of the note shows garlic. 100 grams contain 1.2 mg of vitamin B6., which provides little over half of the daily requirement]