Story at-a-glance -

• Folate is the form of B9 found in leafy greens and other foods and can be directly utilized by your body. For this reason, it’s the preferred form, and is particularly important if you have liver problems
• Folic acid is the synthetic form typically found in supplements. Folic acid is not biologically active in and of itself, but provided your liver is healthy, it will convert folic acid into the active form
• Research suggests 15% of adults over the age of 50 may be deficient in folate, and the older you are, the greater the deficiency. Folate may help lower your risk for heart disease and stroke by lowering your homocysteine level
• Taking baker’s yeast, which contains folates, has been shown to minimize post-exercise immunosuppression in athletes, and folic acid supplementation can help lower the risk of cardiovascular events relating to exertion
• 2018 research found higher folic acid exposure in utero was associated with improved cortical maturation in the child, which in turn predicted a reduced risk for symptoms of psychosis

Folate (vitamin B9) is one of the B vitamins needed for healthy brain development, red and white blood cell production,1 DNA synthesis,2 various metabolic processes3 and the conversion of carbohydrates into energy,4 just to name a few of its functions.

Your body cannot produce folate, thus making it necessary to get it from your diet. Certain folate-producing probiotics (beneficial bacteria), particularly the Bifidobacterium genus, have been shown to raise folate concentrations,5 so the makeup of your gut microbiome may influence your folate status.

Folate is the form of B9 found in leafy greens and other foods6 and can be directly utilized by your body. For this reason, it’s the preferred form, and is particularly important if you have liver problems.

Folic acid is the synthetic form typically found in supplements. Folic acid is not biologically active in and of itself, but provided your liver is healthy, it will convert folic acid into the active form. I’ll discuss these differences further below.

Folate Deficiency Tends to Increase With Age

As with many other important nutrients, folate deficiency may be more common than you think. A large population study7,8 published in 2018 discovered 15% of adults over the age of 50 were deficient in folate, and the older you are, the greater the deficiency.

Rates of deficiency rose from 14% in those aged 50 to 60, rising to 23% in those older than 80, Medical News Today reports.9 Only 8% to 9% of adults over 50 had high folate status. According to the authors of the study,10 “The largest positive predictor of folate concentration was folic acid supplement use.”

Folate Is Important for Heart Health

Folate has many important health functions. It’s been shown to help prevent11 depression, seizure disorders,12 brain atrophy and other neurological problems, for example. Pregnant women need it to prevent premature birth and neural tube defects in their offspring.13

It may also help lower your risk for heart disease and stroke by lowering your homocysteine level.14 A 2016 meta-analysis15 of 30 randomized controlled trials involving 82,334 participants found folic acid supplementation lowered the risk of stroke by 10% and overall cardiovascular disease by 4%. According to the authors, “The intervention effects for both stroke and combined CVD were more pronounced among participants with lower plasma folate levels at baseline.”

The following year, 2017, a meta-analysis16 in The Lancet of 22 randomized trials came to a similar conclusion, finding folic acid in conjunction with vitamins B6 and B12 reduced the risk of stroke by 12%.

Interestingly, while this combination was not associated with any significant reduction in cardiovascular events, folic acid by itself reduced the risk of cardiovascular events by 11%, and the risk of stroke by 20%.

Folate-Rich Yeast Can Protect Athletes From Infections

Stress, as you probably know, can contribute to poor health and early death. This includes physical stress, and even physical stress you’d normally associate with health.

In the case of athletes, excessive physical stress from overtraining and lack of recovery can actually take a significant toll on their health by suppressing immune function. This is why intense and prolonged exercise makes you more prone to infections shortly afterward.

While your best bet is to make sure you sufficiently recover between workout sessions, if the damage is already done, dietary supplements like beta glucan may help get you back in the game faster.

This finding came from a 2013 study17 in the British Journal of Nutrition, in which athletes were given 250 milligrams of baker’s yeast per day for 10 days before a bout of cycling to see whether it would minimize post-exercise immunosuppression.

For clarification, beta glucan is a type of fiber found in baker’s yeast, brewer’s yeast and nutritional yeast, all of which contain B vitamins, including folate.18,19,20 (Baker’s yeast, which was used in this study, contains the folates tetrahydrafolate and 5-methyltetrahydrofolate.21) Of the three, nutritional yeast is the most palatable, though.

It turns out the baker’s yeast supplement did reduce immunosuppression after intense exercise. In fact, the athletes ended up having higher amounts of circulating monocytes two hours after intense exercise — higher in fact than their pre-workout numbers, which is quite surprising.

Another study22 from 2013 assessing the immune-boosting effects of baker’s yeast beta glucan supplementation found those who took 250 mg per day reduced the number of cold and flu symptom days postmarathon by 37%, compared to placebo. It also reduced the urinary tract infection rate in female athletes.

These findings were again confirmed in a 2017 study,23 which found oral supplementation with baker’s yeast beta glucan for 10 days significantly improved monocyte and T cell concentrations, which the researchers said “may result in a decrease in susceptibility to opportunistic infections after strenuous exercise.”

While all three studies used baker’s yeast, with its cheesy flavor, nutritional yeast is far tastier, and a personal favorite. Baker’s yeast does contain slightly higher amounts of folate — 281 micrograms per 12 grams,24 compared to 240 mcg per 16 grams for nutritional yeast25 — but nutritional yeast is still an excellent source.

Folate Protects Athletes’ Heart Health

Athletes can also put their heart health at risk if they’re overtraining. As reported by VeryWell Fit:26

“While intense workouts are typically good for our health and fitness, risk factors linked to cardiovascular disease can be increased. Chronic studies have shown that demanding workouts can place stress on our body.

Research also indicates strenuous physical activity can decrease folic acid levels and adversely affect our heart health over time. Monitoring folic acid status may protect athletes and active adults by reducing their risk of heart problems.”

Intense and prolonged training is also correlated with increased levels of homocysteine,27 which is associated with an increased risk for heart attack, stroke and neurodegenerative problems such as dementia and Alzheimer’s.

B-vitamins, including folate, have been shown to lower homocysteine levels, and research28 shows folic acid supplementation can help lower the risk of cardiovascular events relating to exertion.

Other research29 has shown folic acid supplementation improved vascular function in professional ballet dancers diagnosed with endothelial dysfunction, suggesting this is yet another way by which folate lowers your risk for heart disease. Here, the participants took 10 mg per day for four weeks.

Folate Is Important for Healthy Brain Development

Adequate amounts of folate are extremely important during periods of rapid growth, such as during infancy, adolescence and pregnancy. For this reason, in the 1990s the U.S. mandated grain-based foods to be fortified with folic acid to help prevent neural tube defects in infants born to mothers who may not have consumed enough folate.30

Optimal levels of vitamin B9 has also been shown to deter the development of psychosis and autism in children. A JAMA Psychiatry study31,32 published in 2018 compared school-age children born before the fortification mandate against young people born after, finding higher folic acid exposure in utero was associated with improved cortical maturation, which in turn predicted a reduced risk for symptoms of psychosis.

Folate may also mitigate the risk of pesticide-induced autism, research33 shows. As glyphosate disrupts your gut microbiome, it may lead to a decreased ability to produce folate and induce folate deficiency. Research by UC Davis finds taking a recommended amount of folic acid at the time of conception may lower your child's risk of pesticide-related autism. In a press release, researchers wrote:34

“In the study, children whose mothers took 800 or more micrograms of folic acid (the amount in most prenatal vitamins) had a significantly lower risk of developing autism spectrum disorder (ASD) — even when their mothers were exposed to household or agricultural pesticides associated with increased risk.

Mothers who took less than 800 micrograms and encountered household pesticides had a much higher estimated risk of having a child who developed an ASD than moms who took 800 micrograms of folic acid or more and were not exposed to pesticides.

The associated risk increased for women exposed repeatedly. Women with low folic acid intake who were exposed to agricultural pesticides during a window from three months before conception to three months afterward also were at higher estimated risk.”

The Differences Between Folate and Folic Acid

As you may have noticed in some of the quotes I included, the term “folic acid” is commonly seen and used interchangeably with the term “folate.” It’s important to realize they’re not identical, though.

As mentioned, folate is naturally found in foods as a tetrahydrofolate derivative that enters the metabolic cycle and is metabolized in the mucosa of your small intestine.35

Folic acid is an oxidized synthetic compound manufactured for dietary supplements and food fortification.36 It is initially metabolized in your liver and then enzymatically converted into its active tetrahydrofolate form.

However, if you have low activity of the required enzyme in your liver (which many do due to genetic reasons), it can result in unnaturally high levels of unmetabolized folic acid in your circulation.37,38,39 This increased level has been associated with an increased prevalence of colon cancer40 and an increased risk of prostate cancer.41

Being naturally-occurring, folate also contains all of the related isomers your body needs for optimal use. For all of these reasons, I recommend getting most of your folate from folate-rich foods rather than supplements. If you need a supplement, consider using folate products that list 5-methyltetrahydrofolate (5-MTHF) on the label, not folic acid.42

Folate-Rich Foods

Folate-rich fruits43 topping the U.S. Department of Agriculture’s list include boysenberries, plantains, mangos, oranges, papayas, lemon juice, kiwi. Among vegetables,44 asparagus, peas, turnip greens, beets and okra are among the richest sources.

Animal foods45 with folate include chicken liver,46 egg yolk, feta cheese, mozzarella and cheddar cheese, yogurt and whey. As mentioned, nutritional yeast is also an excellent source.47

Is Folic Acid OK for Kids?

My only exception to this supplement recommendation (folate over folic acid) is when it comes to children’s supplements, and there are two reasons for this exception.

As mentioned, you need healthy liver function for folic acid to be effectively converted into its active form. Whereas many adults do not have healthy liver function, and thus fare better with natural food-based folate, children tend to have healthy liver function and can easily convert the folic acid into its active form.

A second benefit of using folic acid in children’s supplements specifically is that the folic acid molecule is smaller than folate, so folate-containing pills can be made much smaller while still providing the same biological activity or strength as a larger folate-based pill. For children, the size of the pill can be a determining factor for whether they’ll be able to take it or not.