Vitamin B9, or folate, is good for you. In fact, it’s essential for your body to function properly. It plays a key role in the manufacture of blood cells in your bone marrow, it helps produce the molecules DNA and RNA, and it facilitates your body’s use of carbohydrates for energy.

Folate in foods

If you’re a healthy male, and your eating patterns are wholesome, chances are you’re getting all the folate you need. Vitamin B9 occurs naturally and abundantly in vegetables, especially dark green leafy veggies (spinach, kale, etc.), asparagus, broccoli, Brussels sprouts and kidney beans. You also get folate from bananas, avocados, oranges and orange juice. Your body goes through several steps to fully convert folate to a bioactive form called folic acid that your body can metabolize. The National Institutes of Health states that only 50% of the folate in food is bioavailable when consumed; plus, the body does not store it. Therefore, synthetic (manmade) folic acid is used to supplement or fortify foods because it is estimated to be at least 85% bioavailable.

Thus, if you’re already consuming foods high in folate, you may be getting more vitamin B9 than you realize due to the prevalence of food products fortified with folic acid. It’s commonly added to enriched grains/grain flours and fortified cereals. You only have to read ingredients to see how widespread folic acid is. It is also used in multivitamins or as a separate over-the-counter supplement. Some studies have demonstrated that folic acid in take in the U.S. is excessive^[i], and may have possible undesirable effects on health.^[ii]

On the other hand, folate absorption differs among people, and among foods, making it hard to measure and standardize intake amounts. Also, there are people whose conditions (either health or living conditions) result in a deficiency of folate or folic acid, leading to symptoms such as certain types of anemia, muscle weakness, fatigue, mouth sores, cognitive problems, confusion, and depression.

Folic acid and prostate cancer

When it comes to cancer, there is mixed evidence on the role of folic acid. According to the University of Alabama, “Some studies show that folic acid blocks cancer in its early stages. The evidence for prevention is strongest for colorectal cancer. But getting too much folic acid could have the opposite effect by causing cancer cells to grow more easily.”

What about prostate cancer (PCa)? There is some published evidence based on population data and animal studies that excessive bioavailable folate “…may increase the growth of prostate cancer due to its interaction with a high level of expression of PSMA (prostate specific membrane antigen…which is expressed in nearly all prostate cancers and is a marker of disease aggression.”^[iii] In one experiment, a small number of PCa patients on active surveillance consumed reduced levels of dietary folic acid with no apparent ill effects in terms of vitamin deficiency. Over 12 weeks, the average PSA dropped slightly, but was considered insignificant. Thus, the study failed to substantiate that reducing folic acid would lower the risk of PCa growth or progression.^[iv]

Should you take folic acid supplements? This question is probably best handled between you and your doctor, since folate bioavailability has wide variance. The American Cancer Society informs us, “A 10-year study showed that the risk of prostate cancer was increased in men who took 1 milligram (mg) supplements of folic acid. However, the risk of prostate cancer was lower in men who had enough folate in their diets.”

When it comes to the health of your prostate, and PCa risk, in my opinion the key word is excessive. Knowing that there are higher levels of folic acid in the food supply should be heeded. Overall, we have consistently recommended heart health, anti-inflammatory diets as food patterns that promote general wellness. Such diets already consist of foods rich in folate in forms that are bioavailable.

That said, if you have concerning symptoms of folate deficiency, talk to your doctor. A small number of people have a genetic mutation that interferes with metabolizing folic acid, and it can be tested for. Also, symptoms of deficiency overlap with symptoms of many other ways in which health can be compromised, so only a clinical evaluation can determine the underlying problem.

The best advice? Get plenty of balanced nutrition, and when in doubt, consult with a professional regarding supplementation, be it folic acid or anything else.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

[i] Choumenkovitch SF, Selhub J, Wilson PW, Rader JI, Rosenberg IH, Jacques PF. Folic acid intake from fortification in United States exceeds predictions. J Nutr. 2002 Sep;132(9):2792-8.
[ii] Patel KR, Sobczy?ska-Malefora A. The adverse effects of an excessive folic acid intake. Eur J Clin Nutr. 2017 Feb;71(2):159-163.
[iii] Ullevig SL, Bacich DJ, Gutierrez JM, Balarin A et al. Feasibility of dietary folic acid reduction intervention for men on active surveillance for prostate cancer. Clin Nutr ESPEN. 2021 Aug;44:270-275.
[iv] Ibid.