Vitamin B6 Introduction
Vitamin B6, or pyridoxine, is a very active water-soluble vitamin. It exists in the forms of; pyridoxal, pyridoxol, pyridoxamine. These biologically active forms of the vitamin play a fundamental role in its ability to work as a coenzyme for amino acid (protein) synthesis. This particular coenzyme is critical in a variety of amino acid processes.
The coenzyme form of the Vitamin B6 is pyridoxal phosphate (PLP). PLP is responsible for the conversion of the amino acid –tryptophan- to the vitamin B2, or niacin; antibody, and hemoglobin molecule synthesis; and plays a key role in the regulation of certain enzymes in the Central Nervous System. This B-compound coenzyme may also prove critical in the formation of DNA and RNA, or the body’s genetic material or genetic code.
Vitamin B6 is often times supplemented in conjunction with Vitamin B9, and B12, to control homocysteine levels in the blood.[1] This important amino acid has been connected to many chronic illnesses including the number one chronic disease and killer of adults in America, heart disease.
Vitamin B6 Food Sources
Intestinal bacteria manufacture the remaining half of all Vitamin B6 synthesized in our bodies.
| Food | Serving Size | %DV * |
|---|---|---|
| Ready-to-eat cereal, 100% fortified, 3/4 c | 2.00 | 100 |
| Potato, Baked, flesh and skin, 1 medium | 0.70 | 35 |
| Banana, raw, 1 medium | 0.68 | 34 |
| Garbanzo beans, canned, 1/2 c | 0.57 | 30 |
| Chicken breast, meat only, cooked, 1/2 breast | 0.52 | 25 |
| Ready-to-eat cereal, 25% fortified, 3/4 c | 0.50 | 25 |
| Oatmeal, instant, fortified, 1 packet | 0.42 | 20 |
| Pork loin, lean only, cooked, 3 oz | 0.42 | 20 |
| Roast beef, eye of round, lean only, cooked, 3 oz | 0.32 | 15 |
| Trout, rainbow, cooked, 3 oz | 0.29 | 15 |
| Sunflower seeds, kernels, dry roasted, 1 oz | 0.23 | 10 |
| Spinach, frozen, cooked, 1/2 c | 0.14 | 8 |
| Tomato juice, canned, 6 oz | 0.20 | 10 |
| Avocado, raw, sliced, 1/2 cup | 0.20 | 10 |
| Salmon, Sockeye, cooked, 3 oz | 0.19 | 10 |
| Tuna, canned in water, drained solids, 3 oz | 0.18 | 10 |
| Wheat bran, crude or unprocessed, 1/4 c | 0.18 | 10 |
| Peanut butter, smooth, 2 Tbs. | 0.15 | 8 |
| Walnuts, English/Persian, 1 oz | 0.15 | 8 |
| Soybeans, green, boiled, drained, 1/2 c | 0.05 | 2 |
| Lima beans, frozen, cooked, drained, 1/2 c | 0.10 | 6 |
| * DV = Daily Value. DVs are reference numbers based on the Recommended Dietary Allowance (RDA). They were developed to help consumers determine if a food contains very much of a specific nutrient. The DV for vitamin D is 400 IU. The percent DV (%DV) listed on the nutrition facts panel of food labels tells adults what percentage of the DV is provided by one serving. Percent DVs are based on a 2,000-calorie diet. Your Daily Values may be higher or lower depending on your calorie needs. Foods that provide lower percentages of the DV will contribute to a healthful diet. |
Vitamin B6 Uses
Studies suggest Vitamin B6, to be effective in the prevention and treatment of numerous physical and psychological afflictions. In combination with B9 (folate), pyridoxine may be the most important nutrient in the regulator of mood in our psyches’.[3] Through clinical application we know that B6, alone, produces serotonin which dramatically increases our chances of preventing depression.[4] Between 15-39% of all Americans suffering from depression may have low folate levels. Combined with B9 and B12, pyridoxine may be used to treat symptoms of clinical depression and overall “cognitive function” in individuals suffering from this psychological disease.[5] These anti-stress hormones produced by pyridoxine, particularly serotonin, may also aid in the stressors associated with Human Immunodeficiency Syndrome, or even A.I.D.S.[6, 7]
In conjunction with a healthy diet, pyridoxine, may reduce the risks of having diseases associated with the heart.[8] This is in direct correlation to the lowering of homocysteine levels in the blood. The supplementation of Vitamins B6, B9, and B12 may also be important in eliminating the risk factors associated with atherosclerosis.[9]
A clinical study, including pyridoxine alpha-ketoglutarate (a particular compound of Vitamin B6), has proven its unique ability to control blood sugar levels in those suffering from diabetes. A recent study focused on fasting blood sugar levels in relation to Vitamin B6 supplemented in the diet. There proved to be significant reductions of those individuals supplementing with pyridoxine alpha-ketoglutarate, than those receiving placebo, or nothing at all.[10]
The demographic of women concerning proper supplementation of pyridoxine has not been overlooked. Studies have shown lower levels of B6 to be associated with eating disorders, and increased Premenstrual Syndrome (PMS) symptoms.[11, 12] Supplementation with pyridoxine proved more successful than placebo at alleviating (mainly) depression in both eating disorders and stressors related to PMS. Lower levels of B6 in both men and women, however, have also been associated with rheumatoid arthritis and osteoporosis in various clinical applications.[13, 14]
Because of pyridoxine’s ability to produce essential brain chemicals, it has been used as an effective aid in the combatant against Attention Deficit/Hyperactivity Disorder (ADHD) amid children.[15] Neurological chemicals such as dopamine, serotonin, and norepinephrine are dependent upon B6 for proper development and regulation. Supplementation with Vitamin B6 in children suffering from ADHD may improve overall hyperactive and cognitive behavior.[16]
Vitamin B6 Dosages
The RDA for Vitamin B6 was revised in 1998 and is in direct relation to the amount of protein consumed in an individual’s diet. This is due to amino acid metabolism by pyridoxine.
| Age (years) | Men | Women | Pregnancy | Lactation |
|---|---|---|---|---|
| 19-30 | 1.3 mg/day | 1.3 mg/day | ||
| 50+ | 1.7 mg/day | 1.5 mg/day | ||
| All Ages | 1.9 mg/day | 2.0 mg/day |
Vitamin B6 Toxicities and Deficiencies
Vitamin B6 Deficiencies
Pyridoxine deficiency is among the most common of all deficiencies in humans. The United States Department of Agriculture (U.S.D.A.) has reported that some “80 %” of Americans consume less than the Recommend Dietary Allowance for Vitamin B6.[17]
Although it is more stable than most B-complex vitamins, this deficiency continues to be prevalent among western societies. These deficiencies include and are not limited to:
- Depression
- Mental confusion
- Itchy/scaly skin
- Inflamed mucous membranes of mouth
- Convulsions in infants
- Seizure
- Abnormal ECGs (electroencephalograms)
- Change in red blood cells (hypochromic/microcytic anemia)
- Changes in tryptophan metabolism
Vitamin B6 Toxicities
“Mega-doses” of Vitamin B6 can lead to toxicity in humans, although it is rare. The main sign of pyridoxine overdose is the destruction of our sensory nerves. This leads to the loss of feeling in the extremities (i.e. fingers, legs, etc.).
References
1. Malinow MR, Bostom AG, Krauss RM. Homocyst(e)ine, diet, and cardiovascular disease. A statement for healthcare professionals from the nutrition committee, American Heart Association. Circulation. 1999;99:178-182.
2. Clinical Nutrition Service, Warren Grant Magnuson Clinical Center, National Institutes of Health (NIH), NIH. Vitamin E December. 9. 2002. http://www.cc.nih.gov/ccc/supplements/
3. Alpert JE, Fava M. Nutrition and depression: the role of folate. Nutr Rev. 1997;5(5):145-149
4. Bernstein AL. Vitamin B6 in clinical neurology. Ann NY Acad Sci. 1990;585:250-60.
5. Bell IR, Edman JS, Morrow FD, et al. Brief communication: Vitamin B1, B2, and B6 augmentation of tricyclic antidepressant treatment in geriatric depression with cognitive dysfunction. J Am Coll Nutr. 1992;11(2):159-163.
6. Rall LC, Meydani SN. Vitamin B6 and immune incompetence. Nutr Rev. 1993;51 (8): 217-225
7. Kelly GS. Nutritional and botanical interventions to assist with the adaptation to stress. [Review]. Altern Med Rev. 1999 Aug;4 (4): 249-265
8. Rimm EB, Willett WC, Hu FB, et al. Folate and vitamin B6 from diet and supplements in relation to risk of coronary heart disease among women. JAMA. 1998;279:359-364.
9. McKinley MC, McNulty H, McPartlin J, et al. Low-dose vitamin B-6 effectively lowers fasting plasma homocysteine in healthy elderly persons who are folate and riboflavin replete. Am J Clin Nutr. Apr2001;73(4):759
10. Passariello N et al. Effects of pyridoxine alpha-ketoglutarate on blood glucose and lactate in type I and II diabetics. Int J Clin Pharmacol Ther Toxicol. 1983;21(5):252-256.
11. Rock CL, Vasantharajan S. Vitamin status of eating disorder patients: Relationship to clinical indices and effect of treatment. Int J Eating Disord. 1995;18:257-262.
12. Brush MG, Bennett T, Hansen K. Pyridoxine in the treatment of premenstrual syndrome: a retrospective survey in 630 patients. Br J Clin Pract. 1998;42:448–452.
13. Kremer JM, et al. Nutrient Intake of Patients with Rheumatoid Arthritis is Deficient in Pyridoxine, Zinc, Copper, and Magnesium. J Rheumatol. Jun1996;23(6):990-94.
14. Weber P. The role of vitamins in the prevention of osteoporosis – a brief status report. International Journal of Vitaminology and Nutrition Research. 1999;69(3):194-197.
15. Baumgaertel A. Alternative and controversial treatments for attention-deficit/hyperactivity disorder. Pediatr Clin North Am. 1999;46(5):977-992.
16. Kidd P. Attention deficit / hyperactivity disorder (ADHD) in children: rationale for its integrative management. Altern Med Rev. 2000;5(5):402-428.
17. Pao EM, Mickle SJ. Problem Nutrients in the United States. Food Technology. 1981;35:58-62.
