Stress, thyroid function, and the brain’s GABA system form a tightly connected feedback loop. Because each system affects the others, disruptions can create a cycle of stress sensitivity, cognitive fog, and emotional imbalance. Understanding this interconnected network allows clinicians and patients to approach symptoms more holistically—focusing on stress regulation, thyroid support, and nervous system balance to restore harmony across the entire neuroendocrine system.
Laura Lewis, MS
In the United States, alcohol consumption is on the decline [1]. While changes in economics and culture definitely play a role in younger generations avoiding this particular toxin, the mounting evidence and education surrounding the negative health impacts of alcohol support this shift. While its impacts are numerous, here, we will discuss the connection between alcohol and folic acid. Whether or not you possess an MTHFR mutation, alcohol can interfere with your functional folate levels and stand in the way of optimal physical and mental wellness.
Let’s break down how alcohol interferes with folate (especially synthetic folic acid), why this matters more than you might think, and what you can do to protect your health.
The Relationship Between Alcohol and Folic Acid
Low folate levels are a clinical feature of alcoholism [2]. As scientists have worked to better understand folate metabolism, they have also uncovered many of the mechanisms behind the ways in which alcohol inhibits a healthy folate status.
When a healthy person consumes foods or supplements containing folate or synthetic folic acid (vitamin B-9), it first must be converted to a form that can be absorbed through the walls of the small intestine. Folate is then shuttled by the blood to the liver where it must again be absorbed and further processed into L-methylfolate so it can be used by the rest of the body. Excess folate is regulated and controlled by the kidneys and gets excreted in urine [2].
How Alcohol Interferes with Folate
Drinking alcohol affects folate status in a few different ways:
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It reduces absorption in the gut. Alcohol irritates the intestinal lining, which can reduce your ability to absorb folate efficiently from both food and supplements. Specifically, alcohol damages the intestinal epithelium, particularly in the jejunum where folate absorption is most active. Chronic alcohol use disrupts the expression of reduced folate carrier (RFC) and proton-coupled folate transporter (PCFT), both essential for folate uptake [2,3].
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It increases folate excretion. Alcohol is a diuretic, which means you lose more folate through your urine, sometimes before your body has a chance to use it. This effect, compounded by liver impairment, leads to lower serum and tissue folate levels [3].
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It damages the liver. Your liver plays a central role in converting folic acid to its active form. Chronic alcohol use can impair liver function, reducing your ability to metabolize folate properly. It reduces the efficiency of important enzymes and the availability of glutathione (an important antioxidant) and impedes proper methylation [3,4].
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It adds metabolic stress. Processing alcohol consumes NAD+ and generates acetaldehyde, requiring more antioxidant activity and methylation-dependent repair to recover from oxidative stress. This process depletes nutrient reserves, including L-methylfolate [3,5].
Together, these effects can lead to a functional folate insufficiency, even if you’re consuming “enough” folic acid from supplements or fortified foods.
Why Folate Matters
Folate is a B vitamin (vitamin B9) that’s essential for [6]:
- DNA and RNA synthesis
- Cell division and repair
- Detoxification and liver support
- Neurotransmitter production (aka: mood regulation)
- Healthy pregnancy and fetal development
How Does a Folate Insufficiency Affect the Body?
Folate insufficiency may be difficult to detect without a blood test, but not because it is a superfluous nutrient. In fact, folate is necessary for function in nearly every cell of the body, constantly, and can be the rate-limiting factor in crucial metabolic processes.
As your cells divide and grow to replace old, damaged cells, a critical step is correctly copying the DNA. DNA provides instructions for the new cell and those that come after it. Without folate and its coenzymes, DNA cannot be copied. The expression of the proper genes for continued growth and function may not take place [6]. Improper DNA methylation is likely to lead to a less-functional or mutated developing cell [6].
During pregnancy, folate is especially important, as the cells of the growing baby are so rapidly dividing and growing. Chronic and heavy alcohol use in pregnancy leads to reduced folate transport to the fetus [7].
Folate is critical to the metabolism of several important amino acids, including methionine, cysteine, serine, glycine, and histidine [6]. The synthesis of methionine from homocysteine requires not only folate (as L-methylfolate) but also vitamin B-12. Insufficient levels of folate or B-12 can result in decreased synthesis of methionine and high levels of homocysteine, which poses several serious health risks [6]. Normal homocysteine levels are associated with a healthier cardiovascular system and longevity of mental health.
Folate is also necessary for the production of red blood cells with a normal size and shape. Healthy, normal blood cells are necessary for the efficient delivery of oxygen throughout the body [8].
The Added Risk of an MTHFR Mutation
If you have an MTHFR mutation (such as the common C677T or A1298C variants) your body may struggle to convert folic acid into the active form your cells need: L-methylfolate. This means, at baseline, you have reduced enzyme efficiency for processing folic acid [9]. When you pair this issue with alcohol use, which blocks absorption and ramps up demand, functional folate levels can be depleted quickly.
For example, one clinical study reported that women with MTHFR C677T genotype (either homo- or heterozygous) typically had a lower folate status and a higher homocysteine levels than those with functional MTHFR when consuming alcohol, even at moderate levels [9].
For people with an MTHFR mutation, this combination can raise the risk of [6]:
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Low energy and mood changes
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Elevated homocysteine levels (a cardiovascular risk marker)
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Impaired detoxification
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Fertility struggles
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Increased neural tube defect risk in pregnancy
That’s why many health experts recommend avoiding synthetic folic acid altogether if you have an MTHFR mutation. Opt instead for active L-methylfolate to meet daily folate requirements. While it cannot make up for the deleterious effects of alcohol, L‑methylfolate does not require enzymatic conversion by the liver, is highly absorbable, and can be used to support various aspects of health and methylation immediately upon absorption [10].
What You Can Do
While giving up alcohol is a health-forward trend, the majority of adult Americans still enjoy alcoholic beverages from time to time, and chronic alcohol abuse is still a rampant health concern in the US [3]. If you choose to drink regularly, have a history of folate insufficiency, or a known MTHFR mutation, it’s worth taking extra steps to support your folate status.
Here’s what can help:
- Limit alcohol intake, especially around times when your folate needs are high (pregnancy, stress, recovery, or illness).
- Opt for L-methylfolate instead of folic acid, so the liver is not burdened with enzymatic conversion (especially if you have an MTHFR mutation).
- Support your liver with a balanced diet, antioxidants, and methylation-supportive nutrients.
- Get a blood test for homocysteine levels or MTHFR status if you have symptoms of depletion or folate insufficiency.
Can I Take Folate Supplements if I Drink Alcohol?
You are unlikely to experience an immediate adverse reaction between alcoholic beverages and folate supplements.
However, alcohol and folic acid don’t work as a team for anyone, and this is especially important if you have an MTHFR mutation. If you choose to drink, you now know that the absorption of your folate may be impaired by alcohol use. Alcohol depletes your body’s folate stores, makes it harder to activate folic acid, and increases your risk for folate insufficiency-related health issues. Furthermore, folate does not counteract the damage done to your body by alcohol.
Speak candidly with your doctor about your alcohol use to determine if your body is able to healthfully process the amount of alcohol you regularly consume, or whether cutting back (or cutting out) alcohol would be a smart choice for your quality of life. Choosing the right form of folate (L-methylfolate) is a beneficial step while being mindful about your alcohol intake will go a long way in protecting your mood, metabolism, and long-term wellness.