There’s a good reason to believe gut health is linked to skin health. Gut problems are more common in acne patients, and treating those reduces acne. With the why out of the way we should turn to how. What are the gut problems that aggravate acne and how we can treat them?

I spent the last 4 days combing through scientific literature on gut problems. In this rather lengthy post I’ll give you an overview of gut problems, what’s causing them and evidence-based advice on why eating fewer vegetables may be good for your skin.

So grab a cup of green tea, sit back and relax.

Overview of gut problems

Medically the problem is known as irritable bowel syndrome (IBS). IBS is an umbrella term for common digestive problems we all face from time to time, such as bloating, gas, abdominal pain and elimination problems (constipation and diarrhea). But in IBS patients these symptoms occur regularly whereas in healthy person they only visit occasionally. Other common symptoms of IBS include:

• Heartburn
• Chest pain
• Early satiety, meaning you’ll feel full after eating just a bit of food
• Abdominal bloating

Gut problems can also cause non-gut related symptoms, such as:

• Problems with sleep
• Weakness and fatigue
• Dizziness
• Neck and back pain
• Painful menstruation
• Pain during intercourse
• Muscle and joint pain

IBS is fairly common afflicting 12-20% of the population worldwide.

In the past doctors believed irritable bowel syndrome is psychosomatic (it’s just in your head). And certainly things like stress, emotional issues and irregularities in neurotransmitter levels play a role. But research in the past 10 to 15 years has shown that IBS also has an organic cause, namely bacterial imbalance in the gut. And in this post I’m going to focus on that, and we’ll leave stress and emotional issues for another time.

Those pesky little bacteria

In the gut-skin axis post I talked how bacterial imbalance in the gut causes leaky gut syndrome and aggravates acne. It seems that those pesky little bacteria are at it again, this time causing IBS.

Your gut provides a safe residence for billions and billions of bacteria. They digest plant fiber that your body otherwise couldn’t breakdown. In return for steady meals they manufacture nutrients, help to absorb food, fight harmful bacteria and generally keep your gut a happy place (to use such a scientific term). The vast majority of these bacteria live in the colon. The small intestine and abdomen remain relatively sterile.

Two ways this happy balance can get messed up:

• Dysbiosis. This means that the balance of bacteria in the gut gets disturbed. Normally this means harmful bacteria grow out of hands and outnumber the friendly bacteria (probiotics).
• Small intestine bacterial overgrowth (SIBO). Problems can also happen when bacteria (good or bad) migrate to the small intestine in large numbers.

Studies in IBS patients show that some form of bacterial problem is present in just about every case. Add to that the fact that antibiotic treatment usually leads to big improvements in IBS symptoms, and you have a strong case for bacterial problems as a cause in IBS.

When fiber turns bad

Fiber is generally considered as healthy, and in most cases this mainstream wisdom is right on the money. But in IBS patients fiber can cause problems. When bacteria eat fiber they ferment it and produce gases and short chain fatty acids. When the bacterial population in the gut is healthy you’ll benefit from those end-products. But when there’s an imbalance or overgrowth of bacteria things aren’t so great.

• Bloating and gas. These happen when there’s an increase in the number of gas producing bacteria in the gut.
• Smelly flatulence. This happens when there’s an increase in the number of bacteria that produce hydrogen sulfide and other smelly gases.
• Abdominal pain. Probiotic bacteria affect the nerves in the gut and moderate pain sensation. Overgrowth of harmful bacteria can thus make the gut lining excessively sensitive. Add excess gas and bloating and you get abdominal pain. The gut may also be hypersensitive to bile, which is another factor in abdominal pain.
• Constipation. Certain gases produced by bacteria can slow down things in the colon causing constipation.
• Diarrhea. Other gases can speed up things and attract more water in to the colon leading to diarrhea.

Inflammation

In most IBS cases there’s also low-grade inflammation in the gut. Harmful bacteria are always inflammatory and an increase in their number leads to more inflammation.

When harmful bacteria attaches to the gut wall, they start to break it down. Through the small cracks in the gut lining inflammatory substances can leak into the bloodstream. The body naturally doesn’t like inflammatory substances leaking from the gut. So the immune system responds by attacking the bacteria. This of course creates more inflammation.

Inflammation can hinder gut healing. So getting inflammation under control should be one of your priorities.

With enough inflammation you’ll get diagnosed with inflammatory bowel disease (IBD). The main forms of IBD are Chron’s disease and ulcerative colitis. There’s a lot of overlap between IBS and IBD symptoms, so it’s likely that IBD is just an aggravated form of IBS.

Connection to acne

Nobody knows for sure how gut problems cause and aggravate acne. We know that they do, and inflammation is the most likely culprit. Basically, anything that increases inflammation in the body can cause acne.

Gut problems also affect digestion and nutrient absorption and cause shortage of nutrients important for the skin. Finally, and this is little bit of speculation, constant flux of pathogens, inflammatory substances and ‘bad stuff’ from the colon can make the immune system trigger-happy. So it reacts too strongly to otherwise harmless bacteria on the skin.

Science-based gut healing guide

Most papers on IBS note that it’s notoriously difficult to treat. And that most pharmaceuticals do little better than placebos. That said, from everything we’ve talked so far it should be obvious that treating bacterial imbalance is the key to fixing gut issues.

There are several ways we can approach this: antibiotics, pre- and probiotics and managing fiber intake.

Antibiotics

Antibiotics are a double-edged sword. On the other hand overuse of antibiotics probably opened the door for bacterial problems. Most antibiotics aren’t very discriminating. They kill both harmful and helpful bacteria. And in my post about acne antibiotics I talked how they can cause long-term disturbances in the gut flora.

On the other hand, several studies show that antibiotics effectively reduce symptoms in IBS patients. You can kick-start the process with a course in antibiotics that wipes out lot of the gut bacteria. That way you can rebuild from a clean slate.

That said, you absolutely must follow antibiotics with probiotics and gut-friendly diet. Otherwise antibiotics might just aggravate the problem in the long run.

Probiotics

Since the harmful bacteria are behind most of the IBS symptoms it’s no surprise that treatment with probiotics shows improvements across the board. Studies have shown that probiotics can:

• Suppress inflammation in the gut
• Repair gut wall and prevent harmful bacteria from attaching to the gut wall
• Reduce pain sensitivity and alleviate abdominal pain
• Reduce and normalize intestinal gas production
• Alleviate constipation and diarrhea

The gains vary from study to study with most showing symptom improvements from 20% to 80% of the patients.

There’s just one problem.

Often the gains are strain-specific. There are hundreds and hundreds of different strains of probiotic bacteria. The genus Lactobacillus alone has over 100 different strains. Many studies make it clear that benefits from one strain often don’t apply to another strain. So we can’t conclude that all probiotics have the same benefits.

You can see where this becomes a problem. Most manufacturers don’t list specific strains included in their supplements. And we don’t yet have enough information to say which strains are best for each condition. I also suspect that the beneficial strains vary a bit from person to person, given the each of us harbors unique mixture of gut bacteria.

So you really have no way of knowing that the probiotic supplements in your local health store are going to help you.

Does this mean you shouldn’t take probiotics? Of course not. It just means we are flying a bit blind here. This is also the reason it’s a good idea to include a wide-variety of fermented foods into your diet. As different foods have different probiotic bacteria strains you’ll ensure a wider intake.

Prebiotics

There’s also the fact that probiotics rarely cause long-term changes to gut bacteria. They can help while you take them, but benefits fade away after you stop taking them. Prebiotics on the other hand are substances that encourage the growth of existing probiotic bacteria in the gut. Most common prebiotics are non-digestible fibers in fruits, vegetables, grains and legumes.

Studies on prebiotics are quite scarce, but they do show similar benefits than probiotics. But they have a possible downside. Since they are fermented they may aggravate IBS symptoms for some people, just like fiber does.

Fiber

Fiber is a bit tricky for people with gut problems. It can help the gut by providing bulk and feed the probiotic bacteria, but many sufferers say it aggravates their IBS symptoms.

We need to make a distinction between the two types of fiber: soluble and insoluble. Soluble fiber turns gel in water, and it can be fermented by gut bacteria. Insoluble fiber passes through the digestive system with minimal changes. It provides bulk for stools and can bind to toxins and chemicals in the gut.

Both soluble and insoluble fiber can be problematic for IBS patients, but more often than not insoluble fiber is the culprit. For example one study found that cutting insoluble fiber from diet eliminated excess gas from IBS patients.

Fiber for IBS has been studies several times. The overall conclusion is that fiber may be modestly helpful. Here’s a more detailed summary of studies:

• Overall IBS symptoms: Soluble helpful, insoluble possibly harmful
• Constipation: Both soluble and insoluble helpful
• Abdominal pain: Soluble and insoluble either no effect or mildly harmful

From this you might be sorely tempted to just ditch fiber from your diet. But not so fast – I told you fiber is tricky. Because fiber also promotes healthy gut flora:

• Fiber feeds and encourages the growth of probiotic bacteria.
• Animal studies show that fiber prevents SIBO, and the only human study noted that SIBO was more common in people with lower fiber intake.
• Studies on hospitalized patients show that fiber (and probiotics especially) prevents severe post-surgery infections, in medical speak it prevents bacterial translocation.

Fiber and inflammation

There’s also the fact that bacterial fermentation of fiber creates short chain fatty acids (SCFA). In proper amounts these promote gut health. SCFA benefits include:

• Acidification of gut – hinders growth of harmful bacteria.
• Anti-inflammatory – regulate immune system in the gut
• Encourage healing of lesions in the colon
• Decrease the risk of colon cancer by deactivating carcinogenic substances

Studies comparing ulcerative colitis (UC) patients to health controls show lower SCFA levels and impaired SCFA utilization among UC patients. UC is a form of inflammatory bowel disease (IBD), an aggravated version of IBS. In the same vein, introducing fiber and prebiotics increases SCFA levels and can reduce inflammation levels.

Studies using germinated barley foodstuff have been especially encouraging. It has been shown to:

• Reduce systemic inflammation in UC patients
• Reduce UC severity
• Increase probiotic bacteria concentrations in the gut
• Reduce remission of UC
• Improve constipation

In case you are wondering, germinated barley foodstuff is made from brewer’s spent grains by discarding the outer layers of the grain husk. Researchers made it in laboratory for these studies and to my knowledge it’s not commercially available. That said you should get the same benefits from germinated barley.

Other fibers that show positive results:

• Psyllium husk
• Oats

Gluten and food intolerances

IBS patients often have some degree of inflammation in the gut. It’s also been shown that worsening of inflammation aggravates IBS symptoms. So it’s no surprise that there’s research connecting IBS to gluten sensitivity, food intolerances and other gut irritants.

Italian scientists at University hospital of Palermo did an interesting study. They put 160 IBS patients on elimination diet that excluded wheat, all forms of dairy products, eggs, tomatoes and chocolate. After 4 weeks on elimination diet they found that 70 (43%) of the patients improved. Then they challenged those 40 people with wheat and cow’s milk. Out of those 40 people 30 had a negative reaction to both wheat and cow’s milk, 6 to cow’s milk alone and 4 to wheat alone.

So in that study 25% of IBS patients were sensitive to wheat, dairy or both. In other studies negative reactions to food challenge tests range from 15% to 71%. The most common problem foods are:

• Milk
• Wheat
• Eggs

In my mind it’s not completely clear whether food sensitivities cause IBS or the other way around. It’s possible that bacterial imbalance and inflammation create the ideal conditions for food sensitivity reactions. It’s possible that once the gut problems are dealt with food sensitivities also go away.

But one thing is clear. While you are healing the gut you need to avoid foods you are sensitive to. Because eating them causes further inflammation and perpetuates the gut issues.

Herbal remedies, enzymes and other stuff

Given how few successful treatments exists for IBS people veer towards alternative therapies. Luckily we have some research to evaluate their effectiveness.

Peppermint oil

Peppermint oil relaxes muscles and few studies show it improves IBS symptoms. One meta-analysis concluded peppermint oil was deemed successful in 58% of the patients vs. 29% success in placebo (the placebo effect in IBS studies is quite large). Note that peppermint oil doesn’t in anyway fix gut issues, it simply masks symptoms. So it’s not a viable long-term solution.

Other herbal remedies

Herbal preparations from Traditional Chinese Medicine and Ayurveda have been tested in few studies. Results are very mixed. Some show good results, some show no effect. It’s not surprising that some herbs alleviate symptoms, but it’s impossible to draw any conclusions since different studies use different herbs and preparations. At this point, I would recommend giving a miss to these.

Digestive enzymes

One study looked at digestive enzymes for IBS. It found significant reduction in post-meal bloating after a large fatty meal, but no improvements in gas, abdominal pain or nausea. Chuck it as ‘plausible that this could work, but we just don’t know yet’.

I didn’t see any studies on stomach acid (HCL) supplements. But given how low stomach acid levels are a risk factor in SIBO and bacterial imbalance, HCL supplements may help.

Don’t bother stuff

Here are some treatments that have been studied and very likely are useless in IBS:

• Ginger
• Aloe vera
• Acupuncture, reflexology and other ‘energy therapies’

Making sense of all this and some recommendations

I can’t blame you for feeling a bit confused at this point. We’ve covered a lot of contradicting information. So let’s see if we can make some sense of this.

The big thing to get here is the role gut flora. Abnormal gut flora produces abnormal fermentation and leads to IBS symptoms. So fiber that causes no problems for healthy people may be problematic for IBS sufferers.

Furthermore nobody has exactly the same gut flora. Each of us has unique bacterial composition in the gut. And this can cause individuals to react negative to many so-called healthy foods, see FODMAP intolerance as an example.

This means that we can make generic recommendations that more or less apply to people with gut problems. But it also means that you have to experiment and tweak things to hone down to the specific solution in your situation.

Let’s start with some general suggestions:

• Eat a wide variety of fermented foods, such as yogurt, sauer kraut, kimchi, miso, tempeh, kefir, kombucha. Usually these are very simple to prepare at home and require just little bit of preparation. For recipes and how to use fermented foods in cooking see Nourishing Traditions by Sally Fallon (just ignore all the outdated nutrition theories she promotes).
• Try supplementing with probiotics and prebiotics to encourage normalization of gut flora.
• Try eating fewer vegetables. Yes, I said it. Fewer veggies may be better for you. Studies provide evidence that some IBS patients have limited tolerance for fiber.
• Focus on foods that have predominantly soluble fiber (see below). But don’t freak out if and when you eat some insoluble fiber. You may have limited tolerance for it, but even insoluble fiber is important for healthy gut.
• Try low-FODMAP diet to see if FODMAPs are a problem for you.
• Cook hard vegetables thoroughly.
• Remove stems and other tough parts from vegetables like broccoli and cauliflower.
• Peel fruits and vegetables that high in insoluble fiber, especially apples and potatoes.
• Eliminate wheat, dairy and eggs for 3 to 4 weeks to see if they cause problems for you.

Vegetables that have lot of insoluble fiber include:

• Greens (spinach, lettuce, kale, collards, arugula, watercress, etc.)
• Whole peas, snow peas, snap peas, pea pods
• Green beans
• Kernel corn
• Bell peppers
• Eggplant
• Celery
• Onions, shallots, leeks, scallions, garlic
• Cabbage, bok choy, Brussels sprouts
• Broccoli
• Cauliflower

Vegetables with mostly soluble fiber:

• Carrots
• Winter squash
• Summer squash (especially peeled)
• Starchy tubers, yams, sweet potatoes, potatoes – except skins
• Turnips
• Rutabagas
• Parsnips
• Beets
• Plantains
• Taro
• Yuca

Experiment

Your tolerance to amounts and varieties of fiber-rich foods varies. And experimentation is the only way to get to the bottom of this. Track foods eaten and digestive symptoms in a journal. Pretty soon you should be able to note correlations between symptoms and specific foods.

Summary and take-away messages

• Some form of bacteria problem is present in most cases of gut problems. This can be disturbance in the bacterial balance (dysbiosis) or bacteria may have migrated to relative sterile small intestine (SIBO).
• Bacterial problem causes abnormal fermentation of fiber. This contributes to various bowel problems: flatulence, bloating, abdominal pain and elimination problems.
• Overgrowth of harmful bacteria and leaky gut syndrome cause chronic, low-grade inflammation. This can prevent the gut from healing.
• Eradicating bacterial problem is one of the keys to gut healing. This normalizes fiber fermentation and encourages gut healing. Antibiotics might be a good way to kick-start the process, but you absolutely must follow them with probiotics and prebiotics.
• Those with gut problems may have lower tolerance for fiber, and especially for insoluble fiber. Experiment with limited fiber intake.
• Focus on foods that are high in soluble fiber. Make sure to cook well foods that are high in insoluble fiber. Peel fruits and vegetables.
• Include a variety of fermented foods into your diet.
• Experiment with different foods and levels of fiber intake to find what works for you.
• Investigate the role of food sensitivities. Eliminate common problem foods (wheat, dairy and eggs) for 3 to 4 weeks.
• Peppermint oil may improve IBS symptoms. Digestive enzymes and stomach acid supplements may help some patients.

So that’s it for this monster of a post. I hope you found it useful. I’d love to hear questions and comments from you, especially if you have your own gut healing story or have figured out your problem foods. So please share your story in the comments below.