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Too Much Vitamin B Could Be Bad for Your Bones

Danielle Zickl
Photo credit: Thomas Barwick - Getty Images

From Bicycling

  • According to new research published in JAMA Network Open, consuming high doses of vitamin B supplements could up your odds of a hip fracture.
  • The recommended daily allowance for vitamin B12 is 2.4 micrograms (mcg), and the recommended daily allowance for vitamin B6 is 1.3 milligrams (mg).
  • Adhering to the above recommended daily allowances and cross-training can help guard against hip fractures and fractures of other kinds as well.

As an athlete, it’s essential to get the right nutrients so that you can perform at your best. One of them is vitamin B, which plays a role in everything from your energy levels to your heart health to your muscle tone to your brain function.

However, it’s not a case where more is better: Getting too much of this nutrient could put your bones at risk, new research suggests.

The study, published in JAMA Network Open, included 75, 864 postmenopausal women who participated in the Nurses’ Health Study between 1984 and 2014. They were each mailed an initial questionnaire and then one every two years that asked about updates of their medical histories, lifestyles, diets (and supplement use), and disease diagnoses. Additionally, the women were asked to provide information about any hip fractures that occurred.

After reviewing all the data, researchers found a connection between high doses of B6 and B12 supplements and hip fracture occurrences. The group with the highest fracture risk had a high intake of both vitamin B6 and B12—a daily intake of 35 mg or more of vitamin B6 and 20 mcg or more of vitamin B12.

Specifically, taking 35 mg or more of B6 was linked to a 29 percent higher chance of hip fractures compared to those who took in less than 2 mg per day. As for B12, those who consumed 30 mcg or more of it were 25 percent more likely to have a hip fracture than those who took in less than 5 mcg a day. Taking both B6 above 35 mg and B12 above 20 mcg was linked to a 50 percent higher chance of hip fractures.

The researchers aren’t 100 percent sure what the connection between these vitamin B supplements and hip fractures are, but they do know that excessive B6 consumption causes neurological symptoms, “so we may speculate that women who had very high intakes of B6 were more prone to falling,” lead study author Haakon E. Meyer, M.D., Ph.D., a professor in the department of community medicine and global health at the University of Oslo, told Bicycling.

Meyer also notes that previous research has shown that high doses of B6 might speed up bone loss by acting against certain hormones that play a role in maintaining bone mass density.


Because long-term supplementation was more strongly associated with fractures (as opposed to short-term supplementation), Meyer said he can’t rule out the long-term effects on consumption for any population—not just postmenopausal women. However, hip fractures are predominately an issue in elderly individuals, he said.

Rather than taking supplements, Meyer advises getting your vitamin B from foods.

“A varied, healthy diet is recommended and will cover most needs, and the doses associated with increased fracture risk was much, much higher than what can be achieved by eating a normal diet,” he said. (It’s also higher than you’d typically see in a normal multivitamin, too—those in this study were likely also taking high doses of standalone B6 and B12.)

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According to the National Institutes of Health (NIH), adults should get 2.4 micrograms (mcg) of vitamin B12 per day and 1.3 milligrams (mg) of vitamin B6 per day.

Foods rich in vitamin B12:

  • 3 oz of clams, cooked (84.1 mcg)
  • 3 oz of beef liver, cooked (70.7 mcg)
  • 3 oz of rainbow trout, cooked (5.4 mcg)
  • 3 oz of sockeye salmon, cooked (4.8 mcg)
  • 1 cup of low-fat milk (1.2 mcg)
  • 1 large hard-boiled egg (0.6 mcg)
  • 3 oz of chicken breast, roasted (0.3 mcg)

Foods rich in vitamin B6:

  • 1 cup of chickpeas, canned (1.1 mg)
  • 3 oz of beef liver, pan fried (0.9 mg)
  • 3 oz of yellowfin tuna, cooked (0.9 mg)
  • 3 oz of sockeye salmon, cooked (0.6 mg)
  • 3 oz of chicken breast, roasted (0.5 mg)

While patients with certain medical conditions and vitamin deficiencies may require higher doses, otherwise healthy people should avoid high-dose vitamin supplementation. Check with your doctor before taking any supplements in doses above the recommended daily allowance, Meyer said.

To keep your bones strong and guard against fractures of any kind, try adding some type of cross-training to your regular routine. Since cycling isn’t a weight-bearing activity, running, plyometrics, or weight lifting in your off time can help reduce your risk of these kinds of injuries.

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