If you missed Part 1 of this series, you can find it here.
Digestive distress is the most common problem I see in people switching to a Paleo diet. This can range from mild gas and bloating, to changes in stool frequency and consistency (i.e. constipation, diarrhea or alternating between the two), to severe heartburn or abdominal pain. There are three primary reasons people experience these symptoms when they transition to a Paleo diet:
- Low stomach acid.
- Decreased enzyme production.
- Intestinal inflammation.
I’ll cover each of these in more detail below. Before I do that, it’s worth pointing out that in the vast majority of cases, people who have digestive issues on Paleo also had them before. They may have consciously or unconsciously compensated for them by limiting animal proteins (if they have low stomach acid), eating more simple carbohydrates (decreased enzyme production) or limiting intake of fibrous vegetables and fruits (intestinal inflammation). This doesn’t mean the diet they were on before was necessarily more gut-friendly; the symptoms were being managed, but the underlying problems weren’t addressed.
Low stomach acid
Stomach acid is a prerequisite to healthy digestion. The breakdown and absorption of nutrients occurs at an optimum rate only within a narrow range of acidity in the stomach. If there isn’t enough acid, the normal chemical reactions required to absorb nutrients is impaired.
Stomach acid plays a key role in the digestion of protein, carbohydrates and fat. When food is eaten, the secretion of stomach acid (HCL) triggers the production of pepsin. Pepsin is the enzyme required to digest protein. If HCL levels are depressed, so are pepsin levels. As a result, proteins don’t get broken down into their component amino acids and peptides. These undigested proteins putrefy in the gut, and may cause gas, bloating, heartburn and other digestive issues.
At the same time, proteins that escape digestion by pepsin may end up in the bloodstream. Since this is not supposed to happen, the body reacts to these proteins as if they were foreign invaders, causing allergic and autoimmune responses.
Low stomach acid also impairs carbohydrate digestion. Stomach acid (HCL) supports the breakdown and absorption of carbohydrates by stimulating the release of pancreatic enzymes into the small intestine. If the pH of the stomach is too high (due to insufficient stomach acid), the pancreatic enzymes will not be secreted and the carbohydrates will not be broken down properly. As Dr. Norm Robillard explained in his book Heartburn Cured, undigested carbohydrates provoke an overgrowth of bacteria in the small intestine (a.k.a. “SIBO”) which in turn leads to increased gas production and acid reflux. (I’ve written an entire series on low stomach acid and GERD, so check that out if you haven’t already.)
There are numerous causes of low stomach acid. The most common are:
- H. pylori infection. This is extremely common; studies suggest that 1 in 2 people are infected globally. (1) H. pylori suppresses stomach acid production as a survival strategy.
- Stress. Chronic stress has been shown to decrease stomach acid production.
- Acid suppressing drugs. Long-term use of Prilosec, one of the most potent acid suppressing drugs, reduces the secretion of hydrochloric acid (HCL) in the stomach to near zero. (2)
- Low animal protein (i.e. vegetarian/vegan) diet. I haven’t seen studies on this, but my clinical and personal experience suggest that eating a diet low in animal protein decreases stomach acid secretion over time.
- Age. Numerous studies have shown that stomach acid secretion declines with age. In one study researchers found that over 30 percent of men and women past the age of 60 suffer from atrophic gastritis, a condition marked by little to no acid secretion. (3) Another study found that 40% of women over the age of 80 produce no stomach acid at all. (4)
Imagine this scenario: you’ve been on a vegetarian diet for a few years and under a lot of stress at work. You switch (literally overnight) to a Paleo diet where you are now eating meat at least once and often twice a day. Is it any surprise that your digestive system may not respond well to this? The combination of a vegetarian diet, chronic stress and possibly an H. pylori infection would significantly reduce your stomach acid, and thus ability to digest animal protein.
Decreased enzyme production
Digestive enzymes break down larger molecules in the food we eat into smaller molecules that can be absorbed across gut lumen into our bloodstream. They’re found primarily in the mouth (saliva), stomach and small intestine, and are categorized according to the food substrate they break down:
- Proteases and peptidases break down proteins into peptides and amino acids.
- Lipases break fats into fatty acids and a glycerol molecule.
- Carbohydrases break carbohydrates into simple sugars (i.e. glucose/fructose).
- Nucleases break nucleic acids into nucleotides.
If your enzyme production is insufficient, you can’t break down or absorb protein, fat or carbohydrates properly. It’s not hard to imagine that this could lead to digestive issues, is it?
The primary causes of poor enzyme production are:
- Low stomach acid. The pH (acidity) of the chyme (partially digested food in the stomach) must be in a particular range in order to stimulate enzyme production when it enters the small intestine. If the pH is too high due to low stomach acid, enzyme production will be inhibited.
- Stress. Once again, chronic stress rears its ugly head.
- Micronutrient deficiency. Enzymes don’t work alone; they require other nutrients (vitamins and minerals) which act as “co-enzymes”. If your diet is low in certain micronutrients (i.e. B12, iron & zinc for vegetarians/vegans, or magnesium, selenium, vitamin C for those on a standard American diet), or you’re not absorbing them properly due to low stomach acid, your enzyme production will be impaired.
- Western diet. Highly processed, refined and cooked foods contain no enzymes at all. Raw fruits and vegetables are rich in enzymes.
- Age. Some evidence suggests that enzyme production also declines with age.
Decreased enzyme production almost always occurs together with low stomach acid, which creates a digestive double-whammy.
Inflammation is part of the body’s response to harmful stimuli such as pathogens, irritants or damaged cells. It is a crucial aspect of our body’s protective system, and we wouldn’t live very long without it. It is only when inflammation becomes chronic that it becomes a problem. Chronic inflammation in the gut can lead to constipation or diarrhea, gas, bloating and abdominal pain, as well as extra-intestinal symptoms like skin rashes, muscle and joint pain and even depression.
One of the little known manifestations of gut inflammation that may be one reason people struggle when adopting a Paleo diet is a sensitivity to insoluble fiber found in certain fruits, vegetables and nuts and seeds. As I discussed in this article, there are two primary types of dietary fiber: soluble, and insoluble. While soluble fiber can be soothing for the gut, consuming large amounts of insoluble fiber when your gut is inflamed is a little bit like rubbing a wire brush against an open wound. Ouch.
Like low stomach acid and decreased enzyme production, gut inflammation has numerous causes. The most common include:
- Gut infections. Parasites, pathogenic and opportunistic bacteria, and fungi can all cause a low-grade, chronic inflammatory condition.
- Autoimmune disease. Inflammatory bowel disease, including ulcerative colitis and Crohn’s disease, are conditions where the immune system mounts an inappropriate attack against intestinal tissue.
- Western diet. Gluten, sugar, refined flour and other highly processed and refined foods can inflame the gut.
- Environmental toxins. Pesticides and other chemicals like BPA have been shown to disturb inflammatory cytokine production.
- Intestinal dysbiosis. An imbalance of good and bad bacteria, including SIBO (small intestine bacterial overgrowth), can create an inflammatory state.
Note that only two of these causes are exclusively related to diet: environmental toxins and western foods. The others are potentially modifiable by diet, but diet is not the primary cause. If you continue to experience digestive issues after a 30-day trial of the Paleo diet, chances are you have some gut inflammation and one or more of these causes is present. There are some dietary tweaks that can help (which I’ll discuss below), but ultimately the most important thing is to address the underlying cause, and that will probably require additional support (i.e. supplements or medications) above and beyond dietary changes.
First steps in fixing your gut
A discussion of how to fix the gut could fill an entire book. (Indeed, I plan to write that book after my first book.) While I obviously can’t go into that kind of detail here, I can give you some “first steps” that have proven to work well in my practice.
Restore stomach acid production
The first step in restoring stomach acid production is addressing any factors that are inhibiting it. This means getting tested for H. pylori if you suspect it, taking steps to manage chronic stress and avoiding acid-suppressing drugs.
The next step is to take hydrochloric acid (HCL). I describe the rationale and protocol for this in detail in my article called Get Rid of Heartburn in Three Simple Steps, but the short version is this: taking HCL can often help kick start the body’s own acid production. Most patients I’ve treated only need to take HCL for somewhere between 3-6 months, and are then able to gradually titrate off it. A minority of patients, such as elderly people with atrophic gastritis or people that have been on PPIs for many years, may need to remain on HCL indefinitely. That is a much better option than the alternative, which is to suffer from digestive problems as well as the potentially serious consequences of low stomach acid (such as decreased nutrient absorption, bacterial overgrowth, increased susceptibility to infection and even a higher risk of gastric cancer).
Be aware that HCL should always be taken with pepsin — or, better yet, acid-stable protease — because it is likely that if the stomach is not producing enough HCL, it is also not producing enough protein digesting enzymes.
Another way to stimulate acid production in the stomach is by taking bitter herbs. “Bitters” have been used in traditional cultures for thousands of years to stimulate and improve digestion. More recently, studies have confirmed the ability of bitters to increase the flow of digestive juices, including HCL, bile, pepsin, gastrin and pancreatic enzymes. (5) The following is a list of bitter herbs commonly used in Western and Chinese herbology:
- Gentian root
- Beet root
- Goldenseal root
- Milk thistle
- Yellow dock
Bitters are normally taken in very small doses – just enough to evoke a strong taste of bitterness. Kerry Bone, a respected Western herbalist, suggests 5 to 10 drops of a 1:5 tincture of the above herbs taken in 20 mL of water.
Replace digestive enzymes
As I mentioned above, the single most important step in increasing digestive enzyme production is by restoring stomach acid production. This will give the chyme entering the small intestine the proper pH level (acidity), which is what stimulates the pancreas to produce enzymes. Managing chronic stress and ensuring adequate micronutrient (co-enzyme) intake are also important. Raw, fermented foods like sauerkraut, kim chi, kefir or beet kvaas are rich in enzymes and should be consumed regularly if tolerated.
Supplemental nutrients can be helpful for immediate relief. These include:
- Ox bile. While not technically an enzyme, ox bile is one of the most effective supplements for improving fat absorption.
- Acid stable protease. Improves protein digestion; acid-stable protease is able to survive the low pH of gastric juices to further aid in protein assimilation.
- Pancreatin. A mixture of enzymes produced by the pancreas, including lipase (fat digesting), protease (protein digesting) and amylase (carbohydrate digesting).
- Bromelain. An enzyme found in pineapple that helps with protein digestion, and may have systemic anti-inflammatory effects.
- Ginger. A time-tested digestive remedy.
As with HCL, in most cases you will only need to take these nutrients temporarily, until you are able to address the underlying issues. But they can be incredibly helpful in the meantime.
This one is a little harder to give a quick overview of, because there are so many potential causes, and some of those causes require a fairly complex approach. What I can do is give you a few general tips that are helpful in most circumstances, regardless of the cause.
The first step would be trying some tweaks to your existing Paleo or “real food” diet. (You are on a Paleo or “real food” diet, aren’t you? If not, that is the first step.) There are three tweaks I’ve found to be helpful, and they’re listed in the order I suggest you try them:
- Take it easy on the veggies. Some vegetables (and fruits) are quite high in insoluble fiber, which as I mentioned above, can be very irritating to an inflamed gut. One of the easiest ways to address this is to simply reduce the quantity and variety of vegetables you eat. I know this will sound like heresy to some of you, but keep in mind that while vegetables are nutrient-dense foods, a little goes a long way, and there are other more nutrient-dense foods like organ meat and meat. Read this article if you need more info and a pep talk.
- Try a low-FODMAP diet. FODMAPs are specific types of carbohydrate that are poorly digested by certain people, particularly those with dysbiosis and SIBO. Read my article on FODMAPs for more info on how to do this.
- GAPS diet. The GAPS diet is a comprehensive, anti-inflammatory, gut-healing diet. It’s especially helpful with SIBO, dysbiosis, and inflammatory bowel disease (IBD). Check out this article for a primer.
Putting it all together
There’s no question that healing digestive issues can be a confusing and time-consuming process. In my experience it usually takes a good 3-6 months to unravel a chronic digestive issue — and sometimes longer. This may not be the news you were looking for, but setting realistic expectations will help you to stick with a therapeutic approach long enough for it to work.
The changes I suggested in this article should give you a good head start. I’d also recommend checking out a new line of supplements that Robb Wolf and I created specifically to address the challenges we’ve seen people experience as they adopt a Paleo diet — including digestive problems. One of my biggest frustrations as a clinician has been finding supplements that contain exactly the ingredients I want and don’t contain the ingredients I don’t want. For example, in the case of a digestive supplement, I wanted something that had HCL, acid-stable protease, carbohydrate and fat digesting enzymes, cholagogues to stimulate bile production, and bitters to stimulate acid secretion — with the right doses and forms of each — but that product didn’t exist. So I decided to create it myself. You can learn more about it here, and it will be available for purchase (along with the other products in the “Paleo Transition” pack) next week.
Now I’d like to hear from you. Have you experienced digestive issues on a Paleo diet? What have you found to be helpful?
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