Vitamin B6 is involved in countless reactions in the body and is therefore essential for a healthy body. For example, vitamin B6 supports the body with inflammation and functions as an important substance for optimal brain function.
This article is intended to clear up ambiguities and provide you with enough information that you have clarity about the topic of vitamin B6 overdose. All statements made here are backed by scientific studies, so that the topic of vitamin B6 can be objectively examined
the essentials in brief
- Vitamin B6 is one of the organic compounds, some of which cannot be produced by the body itself. It must be obtained from food or supplements because the body cannot produce it on its own.
- The risk of a vitamin B6 overdose is low in healthy people if they do not take any additional vitamin B6 supplements.
- A vitamin B6 overdose can cause nerve damage in the body. This damage can include fatigue, lethargy, dermatitis, numbness, and paralysis.
What is vitamin B6?
As the name suggests, vitamin B6 belongs to the class of "B vitamins". Vitamins are vital organic compounds for humans, some of which cannot be produced by the body itself. Vitamin B6 is one of the vitamins that the body has to absorb through food because it cannot synthesize it itself.
The bioavailability of vitamin B6 is not the same in all foods. If you are not able to absorb enough vitamin B6 through food, you should resort to supplements. (Image source: engin akyurt / unsplash)
The function of vitamin B6 in the body cannot be scientifically explained precisely, but it is associated with various processes as a contributing substance. (1,2,11)
Vitamin B6 is absorbed in the intestine and converted in the liver into the active form, pyridoxal-5-phosphate, P-5-P for short. In this form, it plays a role in over 150 enzymatic reactions in the body. For example, it is said to play an important role in inflammation. (10)
How does vitamin B6 work in the body?
Vitamin B6 mainly regulates central processes in the body's metabolism. The body needs it in order to be able to convert and incorporate proteins. It also plays a role in fat metabolism. Vitamin B6 contributes to the formation of messenger substances in the nerves and thus affects the entire immune system. (1,2,11)
How much vitamin B6 should I take daily?
A person needs a certain amount of vitamin B6 every day so that they can function optimally in the long term and remain healthy. The following table gives guide values for different age groups and genders:
| Old | RDA | UL |
|---|---|---|
| 0 - 1 years | 0.1-0.2mg | 30 mgl |
| 2 - 8 years | 0.5mg (0.4mg) | 40 mg |
| 9 - 18 years | 1.0mg (0.8mg) | 80 mg |
| 19 - 50 years | 1.3 mg | 100 mg |
| over 50 years | 1.7mg (1.5mg) | 100 mg |
| Pregnant women | 1.9 mg | 100 mg |
(3)
The number of mg (milligrams) given above is recommended for daily use. The figures in brackets represent the guide values for women, the numbers outside the brackets for men. These are only guidelines and a doctor should always be consulted in the event of health problems. The abbreviation "RDA" stands for "Recommended Dietary Allowance" and the abbreviation "UL" stands for "tolerable upper intake level". (3)
When and for whom is it useful to take vitamin B6?
In general, it can be said that people with an increased need or a vitamin B6 deficiency should make sure that they consume enough vitamin B6 through a balanced diet.
The table in the "How much vitamin B6 should I take daily" section also clearly shows that people over the age of 20 need more vitamin B6 than children. In addition, doctors can prescribe treatments with vitamin B6 if there is an increased need. (3)
See the sections below for information on exceptions.
What foods contain vitamin B6?
Vitamin B6 can be absorbed into the body through various foods. The following table shows some foods, divided into three groups with high vitamin B6 content to low vitamin B6 content, each per 100 grams of each food:
| 1.2 - 0.9mg/100g | 0.9 - 0.6mg/100g | 0.6 - 0.4mg/100g |
|---|---|---|
| lobster | Potato Chips | goose |
| Salmon | Sesame seeds | veal fillet |
| sardine | mackerel | Chickpeas |
(3)
The first column contains foods with a high vitamin B6 content. The values here range from 1.2 to 0.9 mg of vitamin B6. The middle column lists foods with a moderate vitamin B6 content. The proportion of vitamin B6 ranges from 0.9 to 0.6 mg. The third column shows foods with a rather low vitamin B6 content. Here the values are in a range between 0.6 to 0.4 mg vitamin B6 per 100 grams.
What role does vitamin B6 play in athletes?
Vitamin B6 is sometimes associated with physical performance and it is unclear whether there is a connection between vitamin B6 and sport and how this connection is shown.
Vitamin B6 has no performance-enhancing effect.
A study examined the relationship between supplements containing vitamin B6 and physical performance in athletes. A short-term deficiency has not shown any negative effects on health.
However, supplements also had no significant impact on strength or endurance in the tested athletes. But what can be said is that a vitamin B6 deficiency has negative effects on performance and, above all, coordination. (4.10)
How do I know if I have a vitamin B6 overdose?
If you consume too much vitamin B6 over a long period of time, various symptoms can appear, which can be used to conclude that you have a vitamin B6 overdose. However, some symptoms are not very specific and may have other causes. If you have health problems, you should definitely consult a doctor.
What are the typical symptoms of a vitamin B6 overdose?
The following symptoms were regularly found in test persons during examinations and can be classified as "typical" for vitamin B6 overdose and the resulting nerve damage:
- fatigue
- lethargy
- dermatitis
- numbness
- signs of paralysis
This list is also not final. Furthermore, other symptoms associated with a vitamin B6 overdose may also occur individually. (3)
Is a vitamin B6 overdose harmful?
Vitamin B6 overdoses usually only occur if you take vitamin B6 supplements in addition to normal food. This overdose cannot then be broken down by the body via the urine and can be harmful to the body.
In most cases, however, a short-term overdose does not cause any permanent damage. (3.11)
Is a vitamin B6 overdose reversible?
If you have a vitamin B6 overdose and notice it early on, you can usually take quick action to lower your vitamin B6 level again.
If you suspect an overdose, see a doctor.
Although there are studies that deal with harmful effects, surprisingly little is known about the effects of vitamin B6 in the body. Many studies can determine the influence of vitamin B6 on certain processes, but cannot say exactly how strong this influence is.
In most cases, certain effects only occur in connection with other substances that occur in food, for example, together with pyridoxal-5-phosphate. (3.11)
How can a vitamin B6 overdose occur?
Vitamin B6 overdoses usually only occur - as already indicated above - if you take supplements in addition to normal food.
Salmon contains a lot of vitamin B6, which you need for a healthy body. Vitamin B6 helps the body, for example, to break down fat and create the body's own energy reserves. (Image Source: David B. Townsend / unsplash)
Your body's tolerance is also relatively high, as you can see from the table in the "How much vitamin B6 should I take daily?" section. can see. Nevertheless, it can happen that you have an overdose of vitamin B6 in your body. This phenomenon will be discussed in the following sections.
What forms can vitamin B6 be taken in?
Vitamin B6 can be taken as a supplement in addition to normal food. Supplements come in two categories:
Vitamin B6 in tablet form
Vitamin B6 in tablet form often has a high bioavailability. The tablets can be taken without any aids and usually have a very long shelf life.
However, many people find it uncomfortable to swallow a pill and therefore need liquid so that they can be swallowed well.
Vitamin B6 in liquid form
Vitamin B6 in liquid form is suitable for people who do not like swallowing tablets. It can simply be mixed into a drink and drunk a teaspoon daily.
In most cases, vitamin B6 supplements in liquid form do not last as long as comparable products in tablet form. Additionally, dosing can be more difficult because you have to measure the amount with a teaspoon.
In studies, the bioavailability (how well or poorly the body can absorb a certain substance) of vitamin B6 in food and supplements has hardly differed. (5)
How should vitamin B6 be dosed during pregnancy?
Pregnant women have a higher need for nutrients because they also have to take care of the growing child. This also includes vitamin B6.
A study showed that many of the women examined, who hardly differed in terms of age and state of health, have a vitamin B6 deficiency. Researchers have concluded that it may be advisable for a woman to consider taking vitamin B6 supplements during pregnancy.
It has also been shown that women treated with vitamin B6 during pregnancy had fewer symptoms such as nausea and vomiting. (6.7)
Who is particularly at risk for a vitamin B6 overdose?
People who have a lower tolerance for vitamin B6 are particularly at risk of a vitamin B6 overdose. These are children, the elderly and people with certain diseases.
Sometimes a short-term overdose is accepted.
Vitamin B6 treatments are sometimes prescribed to prevent or treat heart disease, for example, because studies have shown that vitamin B6 could have a positive effect on heart disease. (8th)
A possible link between vitamin B6 and cancer has also been found. Vitamin B6 could play a role in minimizing the risk of cancer.
However, it is still unclear exactly what role it plays and in which other diseases it has an influence. This means that people who take vitamin B6 supplements for cancer treatment are also at an increased risk of vitamin B6 overdose. (9)
Conclusion
Vitamin B6 is an essential nutrient that cannot be produced by the body itself, but which we need for a healthy body. Many effects of vitamin B6 are already known, but many are still unknown.
Unfortunately, the symptoms of can not always be clearly identified because they can be quite different from person to person. Vitamin B6 is available in supplements but does not normally need to be taken if you eat a balanced diet. Vitamin B6 has no proven performance-enhancing effect and an overdose can lead to unpleasant to harmful effects.
References
- Ueland PM, McCann A, Midttun Ø, Ulvik A. Inflammation, vitamin B6 and related pathways. Mol Aspects Med. 2017;53:10-27. doi:10.1016/j.mam.2016.08.001
- BirdRP. The Emerging Role of Vitamin B6 in Inflammation and Carcinogenesis. Adv Food Nutr Res. 2018;83:151-194. doi:10.1016/bs.afnr.2017.11.004
- Institute of Medicine. 1998. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: The National Academies Press. https://doi.org/10.17226/6015.
- EJ van der Beek, W van Dokkum, M Wedel, J Schrijver, H van den Berg. Thiamin, riboflavin and vitamin B6: impact of restricted intake on physical performance in man. J Am Coll Nutr. 1994;13(6):629-640. doi:10.1080/07315724.1994.10718459
- Lindschinger M, Tatzber F, Schimetta W, et al. A Randomized Pilot Trial to Evaluate the Bioavailability of Natural versus Synthetic Vitamin B Complexes in Healthy Humans and Their Effects on Homocysteine, Oxidative Stress, and Antioxidant Levels. Oxid Med Cell Longev. 2019;2019:6082613. Published 2019 Dec 12. doi:10.1155/2019/6082613
- Sharifzadeh F, Kashanian M, Koohpayehzadeh J, Rezaian F, Sheikhansari N, Eshraghi N. A comparison between the effects of ginger, pyridoxine (vitamin B6) and placebo for the treatment of the first trimester nausea and vomiting of pregnancy (NVP). J Matern Fetal Neonatal Med. 2018;31(19):2509-2514. doi:10.1080/14767058.2017.1344965
- Lumeng L, Cleary RE, Wagner R, Yu PL, Li TK. Adequacy of vitamin B6 supplementation during pregnancy: a prospective study. Am J Clin Nutr. 1976;29(12):1376-1383. doi:10.1093/ajcn/29.12.1376
- Jayedi A, Zargar MS. Intake of vitamin B6, folate, and vitamin B12 and risk of coronary heart disease: a systematic review and dose-response meta-analysis of prospective cohort studies. Crit Rev Food Sci Nutr. 2019;59(16):2697-2707. doi:10.1080/10408398.2018.1511967
- Mocellin S, Briarava M, Pilati P. Vitamin B6 and Cancer Risk: A Field Synopsis and Meta-Analysis. J Natl Cancer Inst. 2017;109(3):1-9. doi:10.1093/jnci/djw230
- Rosenberg J, Ischebeck T, Commichau FM. Vitamin B6 metabolism in microbes and approaches for fermentative production. Biotechnol Adv. 2017;35(1):31-40. doi:10.1016/j.biotechadv.2016.11.004
- Ford TC, Downey LA, Simpson T, McPhee G, Oliver C, Stough C. The Effect of a High-Dose Vitamin B Multivitamin Supplement on the Relationship between Brain Metabolism and Blood Biomarkers of Oxidative Stress: A Randomized Control Trial. nutrients. 2018;10(12):1860. Published 2018 Dec 1. doi:10.3390/nu10121860