Beware of the B vitamin-cancer connection

B vitamins do amazing things for your body. B12, for example, keeps your neurological health intact and wards off two of the most serious brain diseases—Alzheimer’s and Parkinson’s disease.

B12 and the B vitamin folate have also been shown to reduce the symptoms of schizophrenia. And B12 is even tied to better bone health.

All of these are great reasons to get your daily dose of B vitamins. But, it seems, you can get too much of a good thing when it comes to B vitamins…

A recent study tied long-term, high-dose B vitamin supplementation to an increased risk of a life-threatening disease — lung cancer.

Think before you supplement…

Researchers from Ohio State University recently found that taking high doses of B6 and B12 supplements for 10 years or more can increase the risk of lung cancer in men.

Men who took up to 20 mg of B6 or 55 mcg of B12 for 10 years had a 30 to 40 percent higher risk of developing lung cancer.

More specifically, men who smoked and took high-dose B6 supplements tripled their lung cancer risk, while smokers who took high-dose B12 supplements quadrupled their risk. Yikes!

And this isn’t’ even the first time high doses of B vitamins have been linked to a heightened cancer risk…

A 2009 study found that people with heart disease who took folic acid and B12 supplements had a 21 percent higher risk of developing cancer. And once again, the heightened cancer risk primarily applied to lung cancer.

Now, it’s important to note that people in both studies were taking a heck of a lot of B vitamins… way more than recommended. The men in this latest study, for example, were taking 11 times the recommended amount of B6 and 23 times the recommended amount of B12 for a whopping 10 years.

That said, both studies are a perfect reminder to supplement cautiously…

Because, the fact is, a lot of B vitamin supplements on the market do contain higher than recommended doses of these otherwise healthy vitamins.

What to do about B…

The last thing this study should do is scare you away from B vitamins… far from it! You still need enough B to keep your brain and body happy.

The secret to B vitamins (like many other vitamins) is sensible supplementing…

Too little can cause problems, but too much can clearly have some serious consequences as well. The recommended dose of B6 is 1.3 to 1.7 milligrams per day, and the recommended dose of B12 is 2.4 micrograms per day.

Another crucial tidbit of information to take away from study is that the heightened cancer risk came from taking individual B6 and B12 supplements — not from taking a multivitamin or from eating B vitamin-rich foods. So those are the safest ways to get enough B vitamins without ramping up your cancer risk.

And FYI for the women out there, the increased cancer risk didn’t seem to apply to us. But that doesn’t mean you should take B vitamins with abandon. Researchers are doing more studies to make sure women really are safe from the B vitamin-cancer connection.

In the meantime, you can keep taking a high-quality, whole-food multivitamin and eat plenty of foods filled with B vitamins, like:

  • Grass-fed milk
  • Eggs
  • Brown rice
  • Fish
  • Legumes
  • Chicken
  • Turkey
  • Mushrooms
  • Grass-fed beef
  • Pumpkin seeds
  • Beets
  • Dark, leafy greens
  • Papaya
  • Oranges
  • Cantaloupe
  • Bananas

And if you do decide to take a B6 or B12 supplement for one reason or another, opt for the whole food variety over the synthetic B vitamin supplements you’ll find in most drug stores. And always be cautious about taking too much for too long.

Editor’s note: When it comes to cancer, your best bet is to know all of your options. Dr. Michael Cutler lists more natural ways to avoid and beat cancer, including the best minerals, herbs, supplements, foods and proven therapies allowed in other countries — but denied to you by American mainstream medicine — all in his comprehensive cancer guide, Surviving Cancer! To get your copy today — plus 3 FREE reports — click here!


  1. Clear link between heavy vitamin B intake and lung cancer — MedicalXpress. Retrieved August 23, 2017.
  2. High doses of vitamin B tied to lung cancer risk, study says — CNN. Retrieved August 23, 2017.
  3. Folic Acid, B12 May Increase Cancer Risk — WebMD. Retrieved August 23, 2017.
  4. Three of the B Vitamins: Folate, Vitamin B6, and Vitamin B12 — Harvard T.H. Chan School of Public Health. Retrieved August 23, 2017.


Jenny Smiechowski

By Jenny Smiechowski

Jenny Smiechowski is a Chicago-based freelance writer who specializes in health, nutrition and the environment. Her work has appeared in online and print publications like Chicagoland Gardening magazine, Organic Lifestyle Magazine, BetterLife Magazine,, and