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Study: Do Vitamin B supplements alter breast cancer risk for women with BRCA mutations?

Vitamins are an essential part of our diet. Vitamin supplements are often used to improve general health. This study explores how vitamin B supplements may affect breast cancer risk in women with BRCA mutations. (5/17/19)

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Contents

At a glance In-depth
Findings     limitations            
Guidelines Resources                           
Questions for your doctor  


STUDY AT A GLANCE

This study is about:

whether B vitamins lower or raise breast cancer risk in women with mutations.

Why is this study important?

Vitamin supplement use is a common. Women with a BRCA mutation can adjust use of vitamins, which may have an impact on breast cancer risk.

Study findings: 

This is a small study that looked at vitamin B supplement use among 400 women in Canada who had a mutation in or .

  • Women who took supplements that included folic acid (synthetic Vitatmin B9), Vitamin B complex, multivitamins, folic-acid specific, or prenatal vitamins - had decreased breast cancer risk compared to women who had never used these supplements if prior child birth history was considered Women who took these supplements had a 55% decrease in risk.
     
  • The decreased risk of breast cancer was observed in women who took moderate levels of folic acid (Vitamin B9) at 8-80 mcg/day or moderate levels of Vitamin B12 (.02-.34 mcg/day).
     
  • Vitamin B6 supplements did not significantly affect breast cancer risk.
     
  • Vitamin B significantly impacted women with BRCA1 mutations, but not women with BRCA2 mutations.

What does this mean for me?

If you are a woman with a BRCA1 mutation, use of Vitamin B9 (folic acid) and/or Vitamin B12 supplements may lower your breast cancer risk. This study suggest that folic acid taken at a level available in over-the-counter supplements may have an impact on breast risk in women with a BRCA mutation. It is important to note that current breast cancer risk-reducing guidelines for BRCA mutations carriers do not address the use of vitamin supplements. Experts do not recommend that women at high risk for breast cancer rely only on diet, exercise or nutritional supplements to lower their risk for cancer.

It is also important to know that the United States Food and Drug Administration () regulates vitamins and other supplements as foods and not as drugs. This means that companies that make and sell vitamins do not have the same strict oversight. Speak with your health care provider before beginning any supplements. If you do decide to take supplements, look for reputable companies.  

What do the guidelines say?

Experts have created national guidelines that outline the medical options for women at high risk for breast cancer. These guidelines include:

  • Increased screening for breast cancer
  • Medications to reduce breast cancer risk
  • Risk-reducing mastectomy

You can read more about the guidelines here.

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Posted 5/17/19

Expert Guidelines

The American Cancer Society (ACS) guidelines on exercise, nutrition and weight for cancer prevention recommend the following: 

Diet and nutrition

  • Follow a healthy eating pattern, including:
    • foods that are high in nutrients in amounts that help you acheive and maintain a healthy body weight.
    • a variety of vegetables, fiber-rich legumes (beans and peas) and whole fruits in a variety of colors. Consume at least 2½ to 3 cups of vegetables and 1½ to 2 cups of fruit each day, depending on your calorie requirements. 
    • whole grains rather than refined grains. At least half of the grains you eat should be whole grains. 
  • A healthy eating pattern that limits or does not include:
    • red and processed meats.
    • sugar-sweetened beverages. 
    • highly processed foods and refined grain products.
  • It is best not to drink alcohol. People who choose to drink alcohol should:
    • have no more than 1 drink per day (women) or 2 drinks per day (men).

Exercise

  • Exercise regularly.
    • Adults should get at least 150 minutes of moderate-intensity activity (equal to a brisk walk) or 75 minutes of vigorous activity (heart rate is increased, breathing is faster and you are sweating) each week, preferably spread throughout the week.
    • Physical activity has been shown to lower the risk of several types of cancer, including breast, endometrial, and colon. It also reduces the risk of other serious diseases including diabetes and heart disease.

Weight

  • Achieve and keep a healthy weight.
    • Being overweight or obese is a risk factor for many cancers, including breast, colon, endometrial and pancreatic. You can control your weight through regular exercise and healthy eating.

Other experts, including the following, also provide guidelines for exercise, nutrition and health: 

Updated: 07/19/2022

Questions To Ask Your Doctor

  • Is it appropriate for me to use Vitamin B supplements?
  • How much Vitamin B should I take?
  • What impact will vitamin use have on my health? on my breast cancer risk?
  • Will increasing the Vitamin B in my diet make a difference?
  • Can you refer me to a nutritionist?

Open Clinical Trials

The following are breast cancer screening or prevention studies enrolling people at high risk for breast cancer:

Additional risk-management clinical trials for people at high risk for breast cancer may be found here.

Updated: 05/28/2025

Peer Support

FORCE offers many peer support programs for people with inherited mutations. 

Updated: 08/06/2022

Find Experts

The following resources can help you locate a nutritionist near you or via telehealth

Finding nutritionists

  • You can find a registered dietician in your area through Eatright.org, the website for the Academy of Nutrition and Dietetics. Search for nutritionists by specialty, including "cancer," "weight management" and "heart health."

Related experts

  • The Livestrong at the YMCA program includes a free 12-week membership and fitness training with certified exercise experts. You can search by zip code for a program near you.  

Other ways to find experts

  • Register for the FORCE Message Boards and post on the Find a Specialist board to connect with other people who share your situation. 
  • The National Cancer Institute (NCI)-Designated Comprehensive Cancer Centers have specialists to manage the symptoms and side effects of cancer prevention or treatment. 
  • FORCE partners with Savor Health® to provide free, personalized, evidence-based nutrition support 24/7 and “on-demand" through their text-based Intelligent Nutrition Assistant (Ina®). You can subscribe here.

Updated: 11/20/2023