Vitamin B6 is a vitamin that belongs to the vitamin B complex group, which plays a role in converting food into energy. Seven forms of the vitamin are known, with the three most common being pyridoxal, pyridoxine, and pyridoxamine. All foods contain either pyridoxine, pyridoxamine, or pyridoxal in some amount. Meats, whole grains, beans, and some fruits tend to be plentiful in B6, but a large enough serving of vegetables can also provide a healthy dose. Vitamin B6 is known to support a wide range of activities in the nervous system and also provides maintenance of red blood cells. It also might reduce cardiovascular disease risk by helping to control levels of homocysteine, (an amino acid) in the blood. Vitamin B6 may also play a beneficial role in individuals with anemia, in women who are pregnant, and among those suffering from depression.
Vitamin B and risk of stroke:
Vitamin B, homocysteine (Hcy), and risk of stroke:
Inflammation is a protective response that elevates blood markers that are useful in predicting the onset of neurodegenerative diseases (such as diabetes, cardiovascular and Alzheimer’s disease). One of these markers is called homocysteine (Hcy). Researchers looked at the relationship between Hcy, vitamin B and risk of stroke in patients with severe hyperhomocysteinemia (HHcy) in this meta-analysis. It was thought that lowering Hcy with folic acid, vitamin B6, and vitamin B12 would improve a patient’s clinical outcomes. Results demonstrate that supplementation with these vitamins did in fact decrease Hcy and showed a tendency toward lowering the risk of stroke. Since HHcy is common among the elderly, authors conclude Hcy is a potential marker in age-related neurodegenerative diseases. (1)
Vitamin B6, vitamin B12, folic acid and homocysteine:
Lowering of homocysteine, an amino acid, with folic acid and vitamins B6 and B12 had a modest, but beneficial effect on stroke prevention or fatal stroke among a population at high risk for cardiovascular disease. Results from this five-year research trial that randomly assigned 5,522 adults with heart disease to either placebo or a daily combination regimen of 2.5 mg. of folic acid (vitamin B9), 50 mg vitamin B6 and 1mg of vitamin B12 found that daily supplements of folic acid, vitamin B6, and B12 for 5 years reduced the risk of stroke by 25%. However, no noticeable effect was observed during the first 3 years of supplementation. During a five-year follow-up period, stroke occurred in 258 of the participants (4.7%). The risk was lower in those who followed the vitamin regimen. The average homocysteine concentration decreased by 2.2 micromol/L in the vitamin therapy group and increased by 0.80 micromol/L in the placebo group. Those who benefited the most from the vitamin treatment included people: younger than 69, with higher cholesterol and homocysteine levels at the start of the study, from areas where folic acid-fortified food isn’t available, who weren’t receiving anti-platelet drugs or cholesterol-lowering drugs at the start of the study. (2)
Vitamin B6 and homocysteine (Hcy):
Human studies have found that homocysteine (Hcy), an amino acid, at a mild to moderately elevated level is associated with the an elevated risk of neurodegenerative diseases such as Alzheimer’s disease, vascular dementia, cognitive impairment or stroke. Numerous studies in recent years investigated the role of Hcy as a cause of brain damage. A meta-analysis of 8 randomized treatment trials (n=37,485) looking at the link between B-vitamins (folic acid, vitamin B6 and/or B12) and risk of stroke, cancer, and vascular diseases found a non-significant decrease in the risk of stroke from B-vitamins. In a separate study, stroke risk was reduced after 3 years of treatment. Patients with no history of stroke and not taking folic acid reported a 25% decrease in the risk of stroke and a decrease in Hcy of 20% or more was associated with a 23% decrease in stroke risk. In studies of folic acid and stroke risk, folic acid was found to have a slight benefit, but the results were not significant. Results were better when folic acid was tested in combination with other vitamins (B6 and B12), though still not major. (3)
Vitamin B and anemia:
Researchers conducted a systematic review of studies looking at the relationship of vitamin supplementation on anemia. Vitamin B6 treats sideroblastic anemia in which a genetic defect or bone marrow disorder produces abnormal ringed sideroblasts instead of healthy red blood cells. (4)
Vitamin B and antiepileptic drugs (AEDs):
Phenytoin and carbamazepine, enzyme-inducing antiepileptic drugs (AEDs), were found to be associated with vitamin B6 deficiency. This study reports that 48% of those taking inducing AEDs were vitamin B6 deficient, compared to only 9% of control subjects. After discontinuation of inducing AEDs and with 6-weeks or more of treatment on levetiracetam, lamotrigine, or topiramate, non-enzyme-inducing AEDs, vitamin B6 deficiency affected only 21% of participants. There was no evidence of folate or vitamin B12 deficiency in any of the participants. (5)
Vitamin B deficiency and depression:
Vitamin B deficiency among depressive patients of Turkish (n=47) and Dutch (n=28) descent was examined to determine the relationship between the frequency of vitamin B deficiency and depression. Depression was diagnosed using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders. The Beck Depression Inventory (BDI) and the 21-item Hamilton Depression Rating Scale (HAM-D-21) were used to determine severity of symptoms. Levels of vitamin B6 and B12, folic acid and homocysteine (tHcy) were measured at baseline. Results indicate patients with vitamin B12 deficiency and hyperhomocysteinemia had significantly higher BDI scores than those with normal levels. (6)
Vitamin B deficiency and pregnancy:
Vitamin B6 deficiency has been associated with early gestational diabetes, neurologic disease in babies, pre-eclampsia, and hyperemesis gravidarum. (7)
Common Highest Vitamin B6 Containing Foods:
| KELLOGG, KELLOGG’S ALL-BRAN Original, 1/2 cup | 3.600 mg |
| GENERAL MILLS, TOTAL Raisin Bran, 1 cup | 2.076 mg |
| KELLOGG, KELLOGG’S PRODUCT 19, 1 cup | 2.070 mg |
| KELLOGG’S ALL-BRAN COMPLETE Wheat Flakes, 3/4 cup | 2.030 mg |
| GENERAL MILLS, Whole Grain TOTAL, 3/4 cup | 2.000 mg |
| KELLOGG, KELLOGG’S SPECIAL K, 1 cup | 2.000 mg |
| Chickpeas, mature seeds, canned, solids and liquids, 1 cup | 1.135 mg |
| KELLOGG’S RAISIN BRAN, 1 cup | 1.124 mg |
| GENERAL MILLS, WHEATIES, 1 cup | 1.111 mg |
| KELLOGG, KELLOGG’S FROSTED FLAKES, 3/4 cup | 1.108 mg |
| Fish, salmon, sockeye, cooked, dry heat, 1/2 fillet | 1.074 mg |
| KELLOGG, KELLOGG’S COCOA KRISPIES, 3/4 cup | 1.017 mg |
| Malted drink mix, chocolate powder, prepared with whole milk, 1 cup | 1.015 mg |
| Malted drink mix, chocolate, with added nutrients, powder, 3 heaping tsp | 0.917 mg |
| GENERAL MILLS, LUCKY CHARMS, 1 cup | 0.903 mg |
| Malted drink mix, natural, with added nutrients, powder, 4-5 heaping tsp | 0.889 mg |
| Fish, tuna, yellowfin, fresh, cooked, dry heat, 3 oz | 0.882 mg |
| MORNINGSTAR FARMS Burger Style Crumbles, frozen, 1 cup | 0.880 mg |
| Beef, variety meats and by-products, liver, cooked, pan-fried, 3 oz | 0.873 mg |
| Malted drink mix, natural powder, prepared with whole milk, 1 cup | 0.861 mg |
| Rice, white, long-grain, parboiled, enriched, dry, 1 cup | 0.836 mg |
| Turkey, whole, giblets, cooked, simmered, 1 cup | 0.792 mg |
| KELLOGG, KELLOGG’S RICE KRISPIES, 1-1/4 cup | 0.776 mg |
| Potatoes, hashed brown, home-prepared, 1 cup | 0.736 mg |
| GENERAL MILLS, CHEERIOS, 1 cup | 0.717 mg |
| Nuts, chestnuts, european, roasted, 1 cup | 0.711 mg |
| Buckwheat flour, whole-groat, 1 cup | 0.698 mg |
| KELLOGG, KELLOGG’S CRISPIX, 1 cup | 0.696 mg |
| GENERAL MILLS, KIX, 1-1/3 cup | 0.690 mg |
| Fish, swordfish, cooked, dry heat, 1 piece | 0.652 mg |
| Fast foods, potato, french fried in vegetable oil, 1 large | 0.629 mg |
| Potato, baked, flesh and skin, without salt, 1 potato | 0.628 mg |
Adapted from: Nutritive Value of Foods, United States Department of Agriculture, Agricultural Research Service, Home and Garden Bulletin Number 72. May be accessed at: https://www.ars.usda.gov/SP2UserFiles/Place/12354500/Data/SR25/nutrlist/sr25w415.pdf and http://www.nal.usda.gov/fnic/foodcomp/Data/HG72/hg72_2002.pdf
Summary and Conclusion: Vitamin B6
- The primary physician should screen patients at risk for hyperhomocysteinemia (high homocysteine level) by sending a blood test for homocysteine level. A meta-analysis by Herrmann W, et al found that lowering homocysteine with folic acid, vitamin B6, and vitamin B12 showed a tendency toward lowering the risk of stroke (1).
- A prevention evaluation by Saposnik G, et al in the HOPE-2 trail demonstrated that 2.5 mg. of folic acid (vitamin B9), 50 mg vitamin B6 and 1mg of vitamin B12 daily for 5 years reduced the risk of stroke by 25%. Interestingly, no noticeable effect was observed during the first 3 years of the supplements. The risk of stroke was lower in those who followed the vitamin regimen. Those who benefited the most included: younger than age 69, patients with higher cholesterol and homocysteine levels at the start of the study, those from areas where folic acid-fortified food isn’t available, and those who weren’t receiving anti-platelet drugs or cholesterol-lowering drugs. (2)
- Vitamin B6 is useful for treating sideroblastic anemia (4).
- Mintzer S, et al found that 48% of subjects taking antiepileptic drugs were vitamin B6 deficient (5).
- Patients with lower B12 levels and higher homocysteine levels had more severe depression than those with normal levels. (6)
- Ensure adequate intake of vitamin B6 in pregnancy. Vitamin B6 deficiency has been associated with early gestational diabetes, neurologic disease in babies, pre-eclampsia, and hyperemesis gravidarum (7).
- To enhance vitamin B6 intake from foods, see the following links: Nutritive Value of Foods, United States Department of Agriculture, Agricultural Research Service, Home and Garden Bulletin Number 72. May be accessed at: https://www.ars.usda.gov/SP2UserFiles/Place/12354500/Data/SR25/nutrlist/sr25w415.pdf and http://www.nal.usda.gov/fnic/foodcomp/Data/HG72/hg72_2002.pdf
References:
1.Herrmann W, Obeid R. Homocysteine: a biomarker in neurodegenerative diseases. Clin Chem Lab Med. 2011 Mar;49(3):435-41. http://www.ncbi.nlm.nih.gov/pubmed/21388339
2.Saposnik G, Ray JG, Sheridan P, McQueen M, et al. Heart Outcomes Prevention Evaluation 2 Investigators. Homocysteine-lowering therapy and stroke risk, severity, and disability: additional findings from the HOPE 2 trial. Stroke. 2009 Apr;40(4):1365-72. http://www.ncbi.nlm.nih.gov/pubmed/19228852
3.Herrmann W, Obeid R. Homocysteine: a biomarker in neurodegenerative diseases. Clin Chem Lab Med. 2011 Mar;49(3):435-41. https://www.seekinghealth.com/media/Homocysteine%20Biomarker%20Neurodegenerative%20Diseases.pdf
4.Fishman SM, Christian P, West KP. The role of vitamins in the prevention and control of anaemia. Public Health Nutr. 2000 Jun;3(2):125-50. http://www.ncbi.nlm.nih.gov/pubmed/10948381
5.Mintzer S, Skidmore CT, Sperling MR. B-vitamin deficiency in patients treated with antiepileptic drugs. Epilepsy Behav. 2012 Jul;24(3):341-4. http://www.ncbi.nlm.nih.gov/pubmed/22658435
6.Güzelcan Y, van Loon P. Vitamin B12 status in patients of Turkish and Dutch descent with depression: a comparative cross-sectional study. Ann Gen Psychiatry. 2009 Aug 13;8:18. http://www.ncbi.nlm.nih.gov/pubmed/19674486
7.Hovdenak N. Haram K. Influence of mineral and vitamin supplements on pregnancy outcome. Eur J Obstet Gynecol Reprod Biol. 2012 Oct;164(2):127-32. http://www.ncbi.nlm.nih.gov/pubmed/22771225
8.Nutritive Value of Foods, United States Department of Agriculture, Agricultural Research Service, Home and Garden Bulletin Number 72. May be accessed at: https://www.ars.usda.gov/SP2UserFiles/Place/12354500/Data/SR25/nutrlist/sr25w415.pdf and http://www.nal.usda.gov/fnic/foodcomp/Data/HG72/hg72_2002.pdf