Vitamin B6 deficiencies are rare in the United States, but there are some groups that might be at risk. Carter says individuals with impaired renal function may have lower levels of plasma B6 concentrations. Those with autoimmune disorders (such as rheumatoid arthritis, celiac disease, and Crohn's disease) and alcohol dependence could be at risk as well. "Vitamin B6 deficiency is also associated with hypochromic, microcytic anemia due to impaired heme synthesis," says Carter. "A deficiency of vitamin B6 also impairs niacin synthesis and inhibits metabolism of homocysteine, which may result in high levels of homocysteine, a risk factor for heart disease. While supplementation with vitamin B6, folate, and vitamin B12 has been shown to lower plasma homocysteine concentrations, current evidence showing lowered risk against heart disease is conflicting."
While most people will get enough vitamin B6 from their diet, Agyeman adds that in some cases, under the supervision of a healthcare professional, some groups like women of childbearing age and the elderly might benefit from taking higher amounts of vitamin B6 from supplements.
Usually if you're vitamin B6 deficient, you also might not be getting enough of the other B complex vitamins like folate and B12. Rueven explains that signs of a deficiency include weakness, fatigue, cheilosis (scaling on lips and cracks on the corner of the mouth), glossitis (swollen tongue), a weakened immune system, neurological problems such as confusion and depression, and a rash on the face, neck, and shoulders.