A brand new study from Harvard researchers, published in the journal Microbiome, arrives at some pretty compelling evidence that eating citrus fruits, such as just one orange or grapefruit per day, can lower your risk of developing depression by 20%.
The researchers believe that other citrus foods get in on the act, too, because citrus promotes a healthy gut microbiome by loading it with the bacteria F. prausnitzzi, which can profoundly influence dopamine and serotonin in the brain (in a good way), and we know all about how important dopamine and serotonin are for depression.
Now I know what you’re thinking (maybe).
How can we tell it was the F. prausnitzzi that was actually behind the lower risk of depression?
We can’t with total certainty.
But…. the researchers created a tremendous model designed to “control” for all the other possible explanations. For example, you might ask whether BMI was a key factor in the relationship and to what extent? The researchers asked that too, and there’s a way to measure that with statistical models.
And so when I say the researchers “control” for “variables” like BMI, it means the researchers get rid of a potential “confounding effect” when it comes to finding a relationship to try to arrive at what seems to be playing a major role in the relationship.
However, just because you can control for tons of things in your model, doesn’t mean you can control for every possible thing so that’s why it’s difficult to prove causation.
But you sure can suggest strong correlation that can point you in the right direction.
Hence, the researchers isolated the important role this lovely F. prausnitzzi bacteria plays in lowering the risk of depression.
Now how does it do it?
The researchers offer a few theories, based on prior research studies.
Recent experimental data support that F. prausnitzii administration in mice ameliorates anxiety and depression symptoms. Furthermore, treatment with either F. prausnitzii or its supernatant raises intestinal serotonin levels in mice [76]. Thus, the SAM cycle I pathway offers a plausible mechanism by which F. prausnitzii may influence depression. SAM is a key methyl donor involved in the synthesis of mood- and behavior-regulating neurotransmitters, including serotonin and dopamine [77]. In support of this, SAM, when used as monotherapy or in conjunction with other antidepressants, has demonstrated encouraging and generally positive results in numerous clinical trials for major depressive disorder [60, 61, 63].
Okay, so there’s a very brief look at the study (And note that the researchers think that other citrus fruits like lemon would provide the same benefit. They just didn’t look at them for the study).
So what does this mean?
A number of things.
First, depending on your ability to tolerate citrus and health conditions determining that, the bacteria alone that you get from eating citrus seems pretty helpful.
And not just for your risk of getting depression. But for all kinds of other things.
Studies have shown that F. prausnitzzi can reduce secretion of some of the worst inflammatory offenders in your body, including TNF-alpha, IL-6, and IL-12.
Elevated levels of each of those is associated with systemic development and worsening of so many diseases.
Second, this study elevates the Himalayan mountain (you pick your peak) of evidence that there’s a profound gut-brain relationship which interferes with our mental health.
Of course there are other factors involved (genetics are massive). If it was were just microbiome, then I’d have beaten this thing long ago, because I’ve tried practically every diet out there, and no serious researchers say it all has to do with gut-brain and diet.
But that relationship does play, along with many other things, a key role in mental health, as well as all manner of other diseases and again — mental health is a disease just like any other. It’s a medical condition just like any other.
I know I’m a broken record on this, but it’s impossible to dispute the decades of research showing this and vitally important for the church to universally recognize.
Third, the great tragedy is that so many Christian leaders continue to (unwittingly and with best intentions) treat mental health as if it’s a spiritual condition. I can understand that indulging in Adultery Wednesday could provoke depression, anxiety, all of that — but for the vast majority of us, this is a medical condition.
And there are so, so many in the church struggling with this disease silently, and that includes many pastors themselves.
Thus, here’s an idea for any spiritual leader that I think would really help get the sheep they so desperately want to help – well, help.
- Study up on this disease.
- Hang a picture of something like the Digestive System in your office as a reminder. (Not just that diet plays a role, but that this disease is a medical condition). You could try a pic of the Bristol Stool Chart but just maybe beta that. Or not.
- Have a list with local psychiatrists and therapists in your desk and hand out copies freely.
We simply have to address this in the church, or else this silent disease will continue to fester. Getting medical treatment saves lives, transforms marriages, enriches lives (including spiritually).
Final note: If diet doesn’t help, believe me, I get it. It’s hard to know everything that comes into play in our disease because researchers have shown it’s not just one thing. Far from it. So we have to be realistic about our disease. Some people hype diet as the cure-all for depression and, unfortunately, research has shown it’s not a panacea. But diet does play a role in affecting the gut-brain axis, which is one of the many things that can influence this physical disease of ours.
Lord bless you in this battle.
For readers in the United States…
Find a psychiatrist here.
Find a therapist here.
For readers, internationally, seek help from a local resource.
For salvation, Christ and Christ alone.
[Painting: Dish with Citrus Fruit, Van Gogh]
