These Vitamins Can Increase the Cancer Risk of Smoking

When it comes to vitamins, you can have too much of a good thing. Certain supplements pose risks to your health when not taken correctly.

According to a study publishing in the Journal of Clinical Oncology, B vitamins in particular are linked to increased cancer risk for men who smoke. Though smoking is already a well-known lethal health risk, smokers who reported long-term, high-dose vitamins B usage were even more likely to develop lung cancer than non-users.

B Vitamins Increase Lung Cancer Risk for Men

The study on vitamin B examined smokers and non-smokers between ages 50-76. The participants reported details on their use of vitamin B from over the past 10 years of their lives.

Researchers then accounted for other health factors like alcohol consumption, family history of lung cancer, and use of anti-inflammatory drugs to isolate the effect of vitamin B.

The results showed that taking high-doses of vitamins B6 and B12 over long periods of time led to a two to four-fold increased risk for lung cancer in men. However, this risk did not apply to women.

A high dose of B vitamins was defined as taking more than the following amounts per day:

• 20 mgs (milligrams) of B6
• 55 mcg (micrograms) of B12

B Vitamins and Health

Luckily these hazardous dosages are far greater than the amounts found in your day-to-day multivitamins.

According to the The National Institutes of Health Office of Dietary Supplements, recommended daily dosages for men ages 51 and over are only:

• 1.7 mg of B6
• 2.4 mcg of B12

However, a well-balanced diet is the best way to get a healthy amount of both these vitamins.

Vitamin B6

The body uses vitamin B6 to keep your immune and nervous systems functioning properly. Vitamin B6 is involved in several important processes, including the production of hemoglobin, which carries oxygen throughout the body.

Most people in the United States get enough vitamin B6 from the foods they eat. A few good sources of B6 include chicken, fish, eggs, potatoes, whole grains, walnuts, and non-citrus fruits.

Vitamin B12

B12 helps the body create many key components, including red blood cells and DNA. Deficiencies of vitamin B12 are also linked to depression, fatigue, and poor memory.

B12 is naturally found in most meats and animal products (like milk and eggs). While there are no natural plant-based sources of B12, there are several fortified options like cereals and non-dairy milk products (ex. soy or almond milk).

How B Vitamins Affect Cancer Risk

One of the more surprising results of the study was that using high doses of B vitamins only increased cancer risk for men.

The researchers theorize that androgen (a male hormone like testosterone) enhances the effect of B vitamins on the body. Using high doses of B vitamins over long periods of time may increase how fast cells grow. This includes the potentially cancerous cells that already exist within men who smoke.

The Best Precaution: Don’t Smoke

Despite the results of the study, additional research is needed to find the true risk caused by B vitamins at high doses.

The most important precaution for lowering cancer risk is to stop smoking and to never start.

The researchers on this study also found that men who quit smoking for at least 10 years before the study, while still taking high doses of B vitamins, did not have a higher risk of lung cancer. The risk for these men was actually equal to those who had never smoked.

B vitamins play a key role in your body’s important functions and in most cases can easily be found in a well-balanced diet.

The doses of B vitamins in everyday multivitamins are well below the potentially hazardous levels revealed by this study.

As with any supplement, take only the recommended daily amount. Talk to your doctor if you feel you might be experiencing a vitamin deficiency to find the best dose for your needs.