What We’re Learning About Genes, Vitamins, and Prevention

If you carry a BRCA1 gene mutation, you may already know that your risk of breast and ovarian cancer is higher than average. But what if certain vitamins, and even other genes, could influence that risk?

Two studies, one from Poland and one from Canada, are offering new insight into how folic acid and a gene called MTHFR may play a role in reducing cancer risk for BRCA carriers, particularly those with BRCA1 mutations.

It’s important to note that the evidence on this topic is currently highly limited and should be taken with caution. However, the few studies that have taken place have shown significant results.

Why Folate Matters

Folic acid (the synthetic version of folate) is a B vitamin that helps your body make and repair DNA. This is especially important if you carry a BRCA1 mutation, because BRCA1 is involved in DNA repair. Getting enough folate may support your body’s ability to repair damage that could otherwise lead to cancer.

But here’s the twist: not everyone processes folic acid efficiently. The MTHFR gene plays a key role in converting folic acid into its active form. Some people have common MTHFR variants (like 677T or 1298C) that reduce the ability to convert folic acid to activated folate. That means even if you’re taking folic acid, your body may not be making full use of it — and this could affect your cancer risk.

What the Studies Found

Polish Study (2012):

Looked at blood folic acid levels and MTHFR gene types in 297 BRCA1 carriers.
Moderate folate levels (53–83 mcg/L) were associated with a 45% lower cancer risk.
Women with the MTHFR 1298AA genotype and high folic acid levels had a 75% reduced risk.
Those with 1298AA or AC genotypes had the most protection with moderate levels.

Canadian Study (2019):

Studied 129 BRCA1/2 carriers with breast cancer and 271 without.
Women who took any folic acid supplements had a 55% lower risk of breast cancer.
Moderate supplement users had a 61% lower risk (OR 0.39), while high-dose users had a 46% lower risk — though this wasn’t statistically significant.
Protective effects were seen only in BRCA1 carriers.

How Much Folate Might Be Helpful?

The protective blood levels seen in studies are often achievable through diet and daily supplements.

Here’s a general guide:

Broad Recommendations

Start low: Begin with 400 mcg unless your provider suggests more.
More isn’t always better: The studies show moderate levels are most protective.
5-MTHF (methylated folate) is recommended for those with MTHFR variants, since it’s already in its active form.

Key Takeaways

Moderate folate levels are linked to lower cancer risk in BRCA1 carriers — especially those with certain MTHFR gene types.
Folic acid supplements (400–800 mcg) may be helpful, but higher doses don’t necessarily offer more benefit.
MTHFR testing may be useful if you’re BRCA1-positive and considering supplements.
Methylated folate (5-MTHF) is a safer and more effective option for people with MTHFR variants.
Always talk to your healthcare provider before starting or changing your supplement routine.

References

Durda K, Jakubowska A, Kąklewski K, Jaworska K, Gupta S, Byrski T, Huzarski T, Gronwald J, Cybulski C, Dębniak T, Tołoczko A, Ashuryk O, Lubiński J. Folic acid and cancer risk in BRCA1 carriers. Hered Cancer Clin Pract. 2012 Apr 20;10(Suppl 3):A6. doi: 10.1186/1897-4287-10-S3-A6. PMCID: PMC3395393.
Kim SJ, Zhang CXW, Demsky R, Armel S, Kim YI, Narod SA, Kotsopoulos J. Folic acid supplement use and breast cancer risk in BRCA1 and BRCA2 mutation carriers: a case-control study. Breast Cancer Res Treat. 2019 Apr;174(3):741-748. doi: 10.1007/s10549-018-05118-3. Epub 2019 Jan 2. PMID: 30603998.

Can Folate Help Lower CancerRisk in BRCA1 Carriers?