One cup of canned chickpeas, for instance, provides 1.1 milligrams of vitamin B6, while three ounces of roasted chicken breast supplies 0.5 milligrams.
Most dietary supplements also tend to contain more than what you need in a day — for some B6 supplements on the market, for example, it can be about 20 to 200 times as much. Taking such high doses of B6 supplements probably won’t cause any negative side effects in the short term, Dr. Tucker said, but the National Institutes of Health recommends that adults take no more than 100 milligrams per day. Taking much more than that, about 1,000 milligrams or more each day for long periods of time, could cause weakness, numbness and pain in the hands and feet; loss of muscle control; and nausea, though most symptoms subside once you stop taking such high doses.
Experts say that if you’re concerned you’re not getting enough vitamin B6 in your diet, ask your doctor for a blood test. If you are borderline or mildly deficient, you may have only minor symptoms, or none at all, and no complications. But if the deficiency becomes severe or prolonged, that could lead to more serious conditions, like microcytic anemiadepression, confusion, fatigue and weakened immunity, which can clear up after B6 levels are restored.
Certain medications or lifestyle habits may also contribute to a B6 deficiency. “The diabetes medication metformin, some hypertension medications, certainly alcohol, tend to cause loss of B6 in the body so that you end up retaining less B6 than you need,” Dr. Tucker said. Heavy drinkers, smokers and those who are taking certain medications should be much more mindful of their B6 levels, she added. People with kidney or malabsorption syndromes like chronic kidney disease, celiac disease, ulcerative colitis or Crohn’s disease may also be prone to B6 deficiency.
Keep in mind that those who are deficient in B6 also tend to be deficient in other B vitamins, Dr. Tucker said, so if you need to supplement your diet, you may be better served by taking a B-complex supplement, which usually contains all eight of the B vitamins in one dose.
But if you’re not deficient, Dr. Tucker added, you probably don’t need to take a supplement.
“I would always endorse a food-first approach,” Ms. Eastwood agreed. “If you are perhaps feeling more fatigued, you don’t feel quite yourself, and you’re aware that you maybe don’t eat a lot of food that contains B6,” then that might indicate you need to turn to more B6- rich food.