The Gut-Brain-Skin Axis

 When I was a child I was obsessed with several things, but two of them were Motown Oldies and aliens. I also had a bad habit of hearing things rather strangely. A good example would be the song "It's in his kiss" by Betty Everett. For quite some time I thought it was actually "It's in his skin." Since I was also into aliens I kept thinking about would would be in his skin besides baby aliens? I must have seen that scene from Alien when my mother wasn't looking...

Today I found a paper that is about how your skin isn't just a reflection of whether or not aliens are gestating within you, but whether you have a healthy gut. This paper has almost all of the real food/paleo blogospheres interests: probiotics, cod liver oil, leaky gut, acne, stomach flora, depression, and aliens. Just kidding about the aliens. Unless you consider our gut flora aliens...who knows?

Acne vulgaris, probiotics and the gut-brain-skin axis - back to the future?

Either way, the authors have put together many interesting puzzle pieces to lend support to the idea that the bacteria in your gut are connected to the condition of your skin and your mood. 

So first there is the association. I bet you are thinking that "of course people with acne aren't happy because acne sucks." But there are a lot of other medical conditions that probably suck more like epilepsy and diabetes. Mental health impairment scores, a measurement of distress, are higher for acne sufferers than from people with these conditions and many other unpleasant illnesses. The gut connection has also been documented, for example in a student of 13,000 adolescents that found that people with acne were more likely to experience stomach problems, in particular abdominal bloating. These and other studies are shining a light on this connection, but it has been theorized for a very long time. The authors of this paper particularly pay homage to a 1930 paper by dermatologists John H. Stokes and Donald M. Pillsbury that contained this hypothesis. 

I would like to get ahold of this paper and have requested it at school. One of the main reasons is it apparently contains evidence that many people with acne have low stomach acid AKA hypochlorhydria. The idea that many people have a sub-clinical form of condition is popular in alternative health circles and I've looked for evidence for some time and it seems to be poorly studied. 

Also, 80 years ago these dermatologists were thinking about stress altering gut bacteria and this leading to leaky gut (abnormal intestinal permeability)!! Whoa. These doctors were ahead of their time.

The lack of research into stomach acid in otherwise "healthy" people is unfortunate, but the growth of heartburn in America has given us some research that we can make some inferences with. For example, half of people on proton pump inhibitors, a heartburn medicine that gives you low stomach acid on purpose, have small intestinal bacterial overgrowth. Wow, I'm so glad I got off those...SIBO is connected with leaky gut pretty well in the medical literature.

 SIBO has also been connected with depression. Most research needs to be done on specifically connecting acne to SIBO, but it's clearly something to investigate. 

Studies found that people with acne have circulating endotoxins from gut bacteria in their blood, which healthy controls did not have. These endotoxins belong in the gut, not in the blood and it's likely they got there through abnormal intestinal permeability. Eventually the body develops reactions to these toxins, which have been connected to depression and anxiety. 

 There is also evidence that decreased digestive transit time can be caused by stress and this increased time can lead to bacterial overgrowth as well. Constipation has been connected to acne in several studies. Other studies showed that people suffering from constipation have low levels of good bacteria. 

So what did they do about this issue in 1930? Their prescription was for fermented milk and cod liver oil...sounds kind of Weston A. Price-ish huh? But wait! Doesn't dairy CAUSE acne? Well Cordain and other paleo authors who have made that connection have rightfully said that dairy contains IGF-1, which IS connected to acne. BUT fermentation reduces this 4-fold. And studies on dairy and acne show the connection doesn't hold for fermented dairy. Dairy also contains the anti-inflammatory protein lactoferrin, which has shown to decrease acne. 

A Russian study showed that drinking milk fermented with lactobactillus reduced acne and an Italian study showed that a probiotic with freeze-dried L. acidophilus and B. bifidum did the same. Saccharomyces cerevisiae has been found to improve both acne and constipation, as well as to improve the integrity of the gut lining. Surely more studies need to be done, but it sounds promising. 

Interestingly probiotics might also help with depression. One study found that depression patients had low levels of lactobactillus. Some other studies have shown depression can respond positively to probiotic treatment. Why? They have been found to increase tryptophan levels, alter serotonin and dopamine turnover (those are the neurotransmitters that antidepressants alter), decrease negative response to stress, increase omega-3 tissue levels, decrease internal lipid oxidation and other good stuff. Unfortunately some of these studies were on mice, so we need more human studies. But there have been a few studies in humans and they have shown positive effects. 

The authors of the paper make a valuable point which is that in many folk health theories there is a focus on things rotting in the gut which causes constipation which causes all manner of problems. Usually the thing they blame is meat. This has led to way too much focus on what ends up being a symptom which is ironically caused by things not rotting in your gut. But rotting is kind of a mean term for the valuable services that gut bacteria perform. They will rot your body, but that happens AFTER you die...

This research is especially important because common treatments for acne include some seriously harsh drugs with terrible side effects, as well as antibiotics, which might end up making other problems worse since they decrease all bacteria instead of improving the gut ecology. 

Isn't it crazy that little tiny weird bacteria can affect your appearance and mood so much? Maybe I was right about the aliens...