Micronutrients are needed by the body to support metabolic processes and to optimize health and well-being. One of these micronutrients includes vitamin B6.
Vitamin B6 is a group of B vitamins necessary for catabolic and metabolic processes within the body. Pyridoxine, or vitamin B6, is essential for the brain’s normal development and in making the immune system and nervous systems healthy. It is a water-soluble vitamin, and excess amounts are excreted through the urine.
Pyridoxine promotes brain health and other functions of the body. It is linked to carbohydrate, protein, and fat metabolism and the development of neurotransmitters and red blood cells.
Since the body does not naturally produce vitamin B6, this micronutrient should be obtained from food or supplementation.
Many people can obtain vitamin B6 from their diet. However, certain people can experience vitamin B6 deficiency.
People at risk of vitamin B6 deficiency include the following:
- People with kidney disease
- Those with autoimmune intestinal disorders such as Crohn’s disease, ulcerative colitis, and celiac disease
- People with autoimmune inflammatory conditions, including rheumatoid arthritis
- People who are dependent on alcohol
The conditions of people at risk of vitamin B6 deficiency interfere with the absorption of vitamin B6.
What are the food sources of vitamin B6?
Vitamin B6 can be found in certain plants and animal foods. You can source vitamin B6 from these foods:
- Poultry products
- Fortified cereals
- Tuna
- Beef liver
- Salmon
- Chickpeas
- Vegetables and fruits such as bananas, dark leafy greens, oranges, papayas, and cantaloupe
Latest research studies have shown that vitamin B6 may play a role in reducing depression and anxiety in those with or without vitamin B6 deficiency.
What is the appropriate dose for vitamin B6?
Recommended Dietary Allowance (RDA) for males and females slightly differ. For males and females aged 4-8 years old, the RDA is 0.6 mg/day, while for male and female children aged 9-13 years old, the RDA increases to 1.0 mg/day. Males, 14-18 should take 1.3 mg/day of vitamin B6 and 1.3 mg/day for those aged 19-50. Males 51 years old and older should take 1.7 mg/day.
Females 14-18 years old have an RDA of 1.2 mg/day, and 1.3 mg/day for those 19-50. Women who are 51 years old and older should take 1.5 mg/day. Pregnant women are advised to take 1.9 mg/day and 2.0 mg/day when breastfeeding their infants.
People who are deficient in vitamin B6 have the following symptoms:
- Cracks at the corner of the mouth and scaling of the lips, which are called dermatitis with cheilosis
- Swollen tongue or glossitis
- Weakened immune function
- Depression and confusion
- Electroencephalographic abnormalities
- Microcytic anaemia
Benefits of vitamin B6
A body of evidence from animal to human studies has documented the benefits of vitamin B6. Here are some benefits supported by studies conducted in recent years.
Vitamin B6 and depression and anxiety
In a study [1] recently published in the journal Human Psychopharmacology, researchers from the University of Reading found that high doses of vitamin B6 could reduce depression and anxiety.
The study, led by David T Field, recruited 478 young adults who were either Bachelor of Science or Master of Science students. The participants were recruited over five years in successive cohorts. The mean age of the students was 23.0 years old (+/- 7.2 years). The students were grouped into two experimental groups and a control group. 3
Participants in the first group received vitamin B6 at 100 mg daily for 30-35 days. The second group received vitamin B12 at a dose of 100 micrograms daily for the same period, while the third group only received a placebo for the same time.
Results showed that those who received B6 significantly reduced their self-reported scores on depression and anxiety compared with those in the B12 and placebo groups. Although those in the B12 group demonstrated significant reductions in depression and anxiety, these reductions were minor compared with those in the B6 group.
The study’s findings indicated that vitamin B6 supplementation could potentially treat depression and anxiety. However, the dosage used for the B6 supplementation was high at 100 mg/day. In the study, none of the participants in the B6 group complained of any adverse effects of the supplement. This suggested that dosage at this level may be therapeutic and safe for at least 30-35 days.
Further analysis of the study showed that vitamin B6 increases the production of gamma-aminobutyric acid (GABA) by acting as a coenzyme in its production. GABA is known to have inhibitory effects on the nervous system. As an inhibitory neurotransmitter, it can calm the brain by limiting the nerve signals of excitatory neurons or blocking certain impulses in the brain. This calming effect can help with stress, depression, and anxiety.
Vitamin B6 and cancer
Vitamin B6 may play a role in the prevention of cancer. Evidence [2] from published studies has shown that people deficient in vitamin B6 are at an increased risk of developing cancer. These studies point out that vitamin B6 is an antioxidant and has anti-inflammatory properties. These properties are needed to prevent DNA damage, which is one of the causes of cancer. However, not all studies found a significant correlation between low levels of vitamin B6 and certain forms of cancer.
Vitamin B6 and cognitive function
Cognitive function may decline with age. Cognitive impairment may be due to genetic and environmental factors. Impairment of cognition is often accompanied by memory problems, which in turn can impact an individual’s overall health and well-being.
A study [3] that recruited 70 men aged 54 to 81 found that people with higher serum concentrations of vitamin B6 were more likely to have high scores in memory tests. In contrast, those with lower vitamin B6 serum concentrations in their body tend to have low scores in memory tests.
However, the findings on vitamin B6 and cognitive functioning are not consistent. A systematic review [4] conducted by Balik and colleagues from the Tufts-New England Medical centre in Boston demonstrated insufficient evidence that vitamin B6 can improve cognitive functioning, especially among older adults.
The review evaluated 14 clinical trials. However, these research studies were of low quality, had small sample sizes and evaluated different clinical outcomes. The heterogeneity in outcomes made it challenging to examine if vitamin B6 alone could improve the cognitive function of the research participants.
Despite the conflicting evidence on whether vitamin B6 can lead to improvements in memory and cognitive functioning, the antioxidant properties of vitamin B6 might explain why this is linked to better cognition.
It has been shown that memory loss and cognitive impairment could be due to cellular ageing and oxidative stress. Since vitamin B6 can delay cellular ageing and fight oxidative stress, it is believed that appropriate doses of this vitamin can slow the progression of cognitive impairment or prevent its occurrence.
Vitamin B6 and cardiovascular disease
When combined with folic acid or vitamin B5 and vitamin B12, vitamin B6 is thought to prevent cardiovascular diseases by lowering homocysteine levels.
However, there is conflicting evidence on the effectiveness of vitamin B6 in reducing the risk of cardiovascular diseases and all-cause mortality. Research studies provide little evidence that vitamin B6 supplementation reduces the risk and severity of a stroke and cardiovascular diseases.
Vitamin B6 and premenstrual syndrome
A meta-analysis of nine studies [5] that recruited almost 1,000 women showed a correlation between vitamin B6 and relief from premenstrual syndrome. However, the correlation is weak, suggesting that vitamin B6, when used alone, is insufficient to relieve premenstrual syndrome symptoms. Further, the studies included in the review are of low quality.
There is a need to conduct more extensive trials to confirm the relationship between vitamin B6 and premenstrual syndrome. Larger trials in the future help elucidate how vitamin B6 relieves symptoms of premenstrual syndrome. Some signs of premenstrual syndrome include the following:
- Mood swings
- Bloating or pain in the stomach
- Trouble sleeping and tiredness
- Breast tenderness
- Feeling irritable, anxious or upset
- Spotty skin
- Greasy hair
- Headaches
Prevention and treatment of anaemia
Vitamin B6 acts as a coenzyme in producing haemoglobin in the blood cells. Due to this role, vitamin B6 has been hypothesized to prevent or treat anaemia caused by a deficiency in haemoglobin.
Haemoglobin is a protein found inside the red blood cells that deliver oxygen to different cells in the body. Low levels of haemoglobin would lead to low oxygen levels in the blood. Insufficient haemoglobin levels lead to feelings of tiredness and weakness.
Hence, supplementation with vitamin B6 may treat or prevent anaemia.
Promotion of eye health
Vitamin B6 has been linked to preventing diseases such as age-related macular degeneration (AMD). It has been shown that high levels of circulating homocysteine in the body can lead to AMD.
A study [6] showed that supplementation with vitamin B6, folic acid, and vitamin B12 could prevent the risk of AMD. It should be noted that AMD is the leading cause of vision loss in older people. To improve eye health, you should take appropriate levels of vitamin B6.
Take-home message
Vitamin B6 remains a vital micronutrient and a member of the vitamin B family. It is thought to play a role in cognitive function and memory. Some of the benefits of this micronutrient include reducing the risk of cardiovascular diseases and certain forms of cancer.
Taking too high doses of vitamin B6 should only be done under the supervision of a medical practitioner. Always consult your doctor when taking vitamin B6 supplementation to ensure that you take the proper dosage over time.
Longevity can be achieved by taking appropriate amounts of micronutrients and macronutrients in the body. Taking vitamin B6 supplementation or eating foods high in vitamin B6 might lengthen lifespan and improve the health span of different population groups.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9787829/
[2] https://pubmed.ncbi.nlm.nih.gov/22116703/
[3] https://pubmed.ncbi.nlm.nih.gov/8602585/
[4] https://pubmed.ncbi.nlm.nih.gov/17210874/
[5] https://pubmed.ncbi.nlm.nih.gov/10334745/
[6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2648137/
