Vitamin B6 (Pyrodoxin)
B6 is just one of the eight water-soluble B Vitamins
responsible for metabolizing fats and proteins and converting carbohydrates into usable blood sugars. B6
itself is composed of three chemical forms, namely pyridoxine, pyridoxamine and pyridoxal, all of which are found in food sources. Pyridoxamine and pyridoxal are natural components of animal sources, while pyridoxine is normally found in both plant and animal foods.
B6 is involved in over 100 enzymatic functions, including the conversion of the amino acid tryptophan into niacin, vitamin B3
.Pyridoxine is also well known for its beneficial and calming effects on the nervous and immune systems.
Role of B6 in red blood cell metabolism
B6 plays a key role in red blood cell metabolism and cellular growth. It is responsible for the production of hemoglobin, a compound within the red blood cells that carries oxygen to body tissue. B6 also increases the amount of oxygen carried within the heamoglobin, thereby also increasing overall vitality. B6 assures lymphoid organ health, (thymus, spleen and lymph nodes), which is necessary for the production of white blood cells, directly responsible for fighting off infections and ultimately enhancing the immune system. Studies show that a B6 deficiency decreases this antibody production, ultimately resulting in a suppressed immune system.1
Role of B6 in red blood sugar regulation
Typically, B6 regulates blood sugar levels by maintaining glucose levels within normal ranges. It is common knowledge among researchers that when the body does not receive enough nourishment in the form of calories, it must use stores of carbohydrates and other nutrients to regulate these glucose levels. B6 is a necessary element in this conversion process and a shortage of the vitamin, will limit the body’s ability to maintain healthy blood sugar levels, often resulting in such symptoms as lightheadedness.
Ironically, studies show that taking B6 supplements will not increase the effectiveness of this process in those people who are already well nourished.2 Because B6 is directly related to glucose regulation, it is not surprising that many health care professionals are prescribing the vitamin in cases of diabetes. In one study that examined the effects of B6 on blood sugar levels in diabetics, pyridoxine alpha-ketoglutarate (a specific form of B6) showed remarkable result after just one month of treatment.3
Role of B6 in synthesis of neurotransmitters
Pyridoxamine plays a large part in the manufacturing of DNA and RNA, the body’s basic genetic makeup. B6 is also a key player in the synthesis of specific neurotransmitters such as serotonin and dopamine in the brain and nerve cells. In an effort to understand the relationship between B6 and serotonin one study looked at people who suffer from depression and migraine headaches, conditions that typically show lower serotonin levels than those of healthy individuals. To date, these studies have not found that B6 is helpful in relieving this symptoms.4
B6 is a significant precursor to the regulation of healthy nerve and muscle cells, it is very important for adequate mental functioning and nerve conduction. In cases of alcoholism that have resulted in neuropathy, B6 is shown to improve and prevent symptoms of abnormal nerve sensations in the arms and legs.5 Studies also continue to look into the possible effectiveness of B6 in other neurological conditions such as seizures, chronic pain and Parkinson’s disease.
B6 may also show promise in cases of Attention Deficit/Hyperactive Disorder (ADHD). Researchers know that B6 is extremely important for normal brain development and functioning. It is key to the synthesis of neurotransmitters found in the brain, such as serotonin, dopamine and norepinephrine. In one study, methylphenidate (a common ADHD drug) was compared to B6 in regard to effectiveness in reducing symptoms of the disorder. It was found that pyridoxine was actually better and more effective for improving behavior in these hyperactive children.6
Vitamin B6 for depression
Today, because of the vitamin’s positive effects on the immune system and its ability to calm the nervous system, B6 is considered the ‘anti-stress’ vitamin, improving the body’s ability to cope in demanding or stressful conditions.
Depression is normally linked with a deficiency in vitamin B9 (folic acid). Studies confirm that between 15 and 30 percent of people suffering from depression also present with low folic acid blood levels. Accordingly, those with the lowest levels of folic acid tend to also experience the deepest depression. In studies homocysteine levels reveal a more accurate reading of folate than regular blood tests, so when folate levels do not return to normal even after increased supplementation, often B6 and B12 are required to lower these homocysteine levels and improve depression.7
Vitamin B6 reduces the risk of heart diseases
Numerous studies show that a diet that is consistently low in these B6 rich foods will significantly raise the risk of heart disease. Researchers believe that B6 in combination with Vitamin B9
and Vitamin B12
will help regulate levels of the amino acid homocysteine, normally found in the blood. Elevated levels of homocysteine have been shown to damage the coronary arteries and promote platelets (blood clotting cells) to bind and create clots.7
The American Heart Association now recommends eating a proper diet, rich in B vitamins, instead of adding further vitamin supplements, however it also notes that in some situations where homocysteine levels are already elevated, and there is a family history of heart disease, it may be prudent to add B6 supplements.
B6 has shown positive results in cases of nausea associated with pregnancy. A review of recent studies concludes that in fact, B6 may help to reduce the severity of the symptoms, especially during the early stages of pregnancy.8
Vitamin B6 for premenstrual syndrome
Many supplements play a part in reducing the symptoms of premenstrual syndrome. In the past, the majority of studies have not shown B6 to be helpful in this area, however, an in-depth review of the studies completed to date, has now concluded that B6 may in fact, be more helpful than a placebo in controlling and improving symptoms of PMS, especially depression.9 As well, independent reports from healthcare professionals and women who have used B6 for this purpose also claim their symptoms have decreased in intensity and frequency after B6 use. It should be noted however, that any decrease in symptoms could take up to three months.
Many studies are now looking to B6 in cases of eating disorders such anorexia and bulimia. It has been revealed that in 20 percent of anorexia cases admitted to hospital, Vitamin B2 and Vitamin B6 levels were significantly low. Other studies conclude that as many as 33 percent may also suffer from a deficiency in both B2 and B6. Researchers state that diet alone can make vital changes in the B vitamin levels, but in some cases it may be necessary to supplement these vitamins, especially in cases where symptoms such as depression are quite severe.
Since B6 levels are much lower in cases of HIV, osteoporosis, burn victims and rheumatoid arthritis, supplementation of the vitamin could be very helpful for reducing the symptoms as suggested by preliminary studies. In cases of carpal tunnel syndrome (CTS) there are still conflicting results, so further research is needed to fully understand the effects of B6 in this situation.
Vitamin B6 deficiency is rare in the US however; those at risk tend to be the elderly who may not receive a proper diet or the nutrients it provides. Symptoms of B6 deficiency may take some time to appear and usually don’t manifest until well after the body has become depleted. The most common symptoms are dermatitis (skin disorders), glossitis (swollen, painful bright red tongue), convulsions, confusion and depression. In some cases anemia may also result.
Natural sources of Vitamin B6
Vitamin exists in its three natural forms found in a variety of foods including; beef liver, lentils, chicken, turkey, shrimp, salmon, tuna, soybeans, nuts, brown rice, carrots, sunflowers seeds, wheat germ, avocados, peanut butter, pork, whole grains, bananas and an array of vegetables.
Too much B6 on the other hand is also problematic and can result in nerve damage. Although it is reversible once excess sources of B6 are removed form the diet, according to the Institutes of Medicine; doses in the range of 500 mg per day can cause neuropathy. It is for this reason that the Food and Nutrition Board of the Institute of Medicine has established a tolerable intake level for adults of up to 100 mg per day. The recommended dose of B6 however, for women over 51 is only 1.5 mg and for men over 51, it is only 1.7 mg. It is stressed as well, that supplementation is rarely needed if proper nutrition is followed.
B6 has many drug interactions so it is best to speak with a health professional prior to using it, especially if you are taking any medications or are pregnant or nursing.
- Chandra R and Sudhakaran L, “Regulation of immune responses by Vitamin B6”, NY Acad Sci, 1990; 585:404-423
- Leyland DM and Beynon RJ, “The expression of glycogen phosphorylase in normal and dystrophic muscle”, Biochem J ,1991; 278:113-7.
- 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.
- Bernstein AL. Vitamin B6 in clinical neurology, Ann N Y Acad Sci, 1990;585:250-60
- Vinik AI, “Diabetic neuropathy: pathogenesis and therapy”, Am J Med, 1999; 107:17S-26S.
- Kidd P, “Attention deficit / hyperactivity disorder (ADHD) in children: rationale for its integrative management”, Altern Med Rev, 2000;5(5):402-428.
- Alpert JE, Fava M, “Nutrition and depression: the role of folate”, Nutr Rev, 1997;5(5):145-149
- Selhub J, Jacques PF, Bostom AG, D'Agostino RB, Wilson PW, Belanger AJ, O'Leary DH, Wolf PA, Scaefer EJ, Rosenberg IH, “Association between plasma homocysteine concentrations and extracranial carotid-artery stenosis”, N Engl J Med, 1995, 332:286-291.
- Jewell D, Young G, “Interventions for nausea and vomiting in early pregnancy (Cochrane Review)”, Cochrane Database Syst Rev, 2002;(1):CD000145.
- 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.