In our latest question and answer, the pharmacist discusses whether or not Avena sativa interacts with antidepressant medication.
Can I take Avena sativa safely along with my prescribed antidepressant and anxiety medications (SSRI, SNRI, bupropion, etc)?
Avena sativa, more commonly known simply as oat, is not known to interact with antidepressant medication.
However, some preliminary studies show that Avena sativa (oat) may have inhibitory effects on an enzyme known as monoamine oxidase–B (MAO-B), which could increase levels of the neurotransmitter dopamine in the brain.
Theoretically, this increase in dopamine could in some way influence or interact with pharmaceutical drugs that also affect this neurotransmitter, like Wellbutrin (bupropion).
Nevertheless, there haven't been any large-scale studies evaluating the safety or efficacy of Avena sativa (oat) in treating depression and no interaction studies have completed between it and common antidepressant drugs.
Overall though, a significant interaction between Avena Sativa and antidepressants (even Wellbutrin) is unlikely, for numerous reasons.
First of all, most antidepressants don't affect dopamine.
SSRIs (selective serotonin reuptake inhibitors), the most commonly used class of antidepressants, affect serotonin while SNRIs (serotonin-norepinephrine reuptake inhibitors) affect serotonin and norepinephrine, not dopamine.
As it concerns Wellbutrin (bupropion), which does affect dopamine, the antidepressant effects of the drug are not thought to be solely due to its influence on dopamine concentrations (it also affects norepinephrine and likely other areas in the brain as well).
Even if Avena sativa (oat) does increase dopamine concentrations, it isn't thought to be to a clinically significant degree where it would influence the effects or actions of Wellbutrin (if anything, it may augment its effects).
Additionally, Avena sativa (oat) is widely consumed and there have been essentially no reports, even anecdotal, of it causing any significant interactions with any pharmaceutical agent, let alone antidepressants.
So, while you can feel pretty confident there is no interaction here, I'll discuss the topic in more detail in the sections below.
Avena sativa, better known simply as 'oat', is a cereal grain. Avena sativa, a breakfast staple for many, doesn't simply contain a few key nutrients, like carbohydrates and proteins.
Analysis of Avena sativa shows that it is composed of a wide range of constituents, including:
Avena sativa has been extensively studied for its health benefits is some areas, but not others (like depression, improved cognitive performance, and sexual enhancement).
Where Avena sativa seems to really shine is in its ability to lower cholesterol levels, decrease the risk of cardiovascular disease and lower blood sugar. This is likely largely due to the soluble fiber contained in Avena sativa.
For lowering cholesterol, for example, studies show that consuming whole oats, which contains the soluble fiber beta-glucan, significantly reduce total cholesterol and LDL. For each gram of beta-glucan consumed (contained in about 15 grams of oats), total cholesterol decreases on average by 1.4 mg/dL and LDL by about 1.2 mg/dL.
The fiber content of Avena sativa is so well-studied that per FDA guidelines, food products containing whole oats can market the health claim that they reduce the risk of heart disease (if they contain at least 750 mg of soluble fiber per serving).
As stated, oats have been purported to have other health benefits as well, like improved sexual and cognitive performance. Even though studies do show that it can increase blood flow and nitric oxide levels, as well as may improve cognitive processing, these effects are far from being conclusive.
In terms of Avena sativa treating depression, preliminary data suggests it may have some effect on increasing dopamine levels by its effects of MAO-B (monoamine oxidase–B).
MAO-B is an enzyme that is involved with the metabolism (i.e. breakdown) of the neurotransmitter dopamine, which is known to play a key role in a variety of neurological processes and diseases.
Inhibiting MAO-B, which studies show Avena sativa may do, could increase levels of dopamine, due to a decrease in the metabolism of the neurotransmitter.
Lab studies have shown that Avena sativa likely has some inhibitory effect of MAO-B and EEG tests in rats showed certain changes in electrical frequencies in the brain that are known to be influenced by dopamine.
In terms of what this means in terms of physiological changes, there have been studies done in humans that have examined whether or not Avena sativa could improve cognitive performance (partly as a result of an increase of dopamine).
One such study concluded the following:
Taking 1600 mg of oat herb extract [from Avena sativa] may acutely improve attention and concentration and the ability to maintain task focus in older adults with differing levels of cognitive status.
There haven't been any studies, however, testing the actual effectiveness of Avena sativa in treating depressive disorders in humans and none that have compared it to traditional antidepressant drugs.
Avena sativa isn't known to interact with any drugs, let alone antidepressants.
However, since Avena sativa does contain a good amount of fiber, it may alter the absorption of some, and shouldn't be taken at the same time as those that are recommended to be taken on an empty stomach, like levothyroxine.
As it concerns antidepressants specifically, there theoretically could be a concern with Wellbutrin (bupropion)
Since Avena sativa could increase dopamine levels (via MAO-B inhibition), it could alter our response to pharmaceutical antidepressants that affect dopamine, (like Wellbutrin).
We don't have a full understanding of how Wellbutrin works but know that it inhibits the reuptake of dopamine and likely norepinephrine as well.
Studies also show that the administration of dopamine and norepinephrine-blocking drugs reduce the antidepressant effects of Wellbutrin, so we certainly know this mechanism is important.
Wellbutrin is not known to have any effects on MAO-B though, and small increases in dopamine (if they occur to a significant extent at all in humans after consuming Avena sativa) likely won't have any negative effects or alter how the drug works to a clinically significant extent.
Overall, you can feel pretty confident that Avena sativa doesn't interact with antidepressant medication.