A study published recently in JAMA Network Open found that very high intake of vitamins B6 and B12 from supplements (much higher than the Recommended Dietary Allowances) was associated with increased risk of hip fracture in women. In this prospective cohort study, 75,864 postmenopausal women in the U.S. were followed for 30 years. Vitamin B6 intake of 35 milligrams (mg) per day or higher (versus less than 2 mg/day) and vitamin B12 intake of 30 micrograms (mcg) per day or higher (versus 5 mcg/day) were associated with increased fracture risk. Women with high intake of both vitamins from supplements had an almost 50 percent higher risk of hip fracture compared with women with low intake of both vitamins.
The Recommended Dietary Allowance for vitamin B6 is 1.3 mg/day for women and men ages 19 to 50 years. This target increases for individuals over 51 and women who are pregnant or lactating, but never passes 2 mg/day. The Recommended Dietary Allowance for vitamin B12 is 2.4 mcg/day for women and men 14 and older. Most people do not need supplements to reach these levels, as these vitamins are commonly found in many foods. It is very difficult to get excessively high levels from diet alone. Even for people who may be at risk for vitamin B12 insufficiency, such high levels of supplementation are unlikely to be necessary.