Caffeine, alcohol, herbs and other food-related aspects

In this lesson I will discuss other food, nutrient and digestion-related factors that can have an effect on gut symptoms.

COFFEE/CAFFEINE

Whether coffee or caffeine affect the gut seems to be very individual. My advice: moderation – caffeine is not an essential nutrient (though some might disagree with me :D).

Caffeine has been linked to a higher risk of diarrhea. It is a stimulant that can induce GI contractions and stimulate stomach secretions. One study saw that coffee stimulated contractions in the colon in 29% of the study participants in 4-30 minutes after drinking it – however, what is interesting is that decaffeinated coffee had similar effects, so caffeine wasn’t probably what caused the effects. (1)

Coffee In 3 Forms

People with IBS often avoid coffee and caffeinated drinks, but studies are conflicting in that some studies connect caffeine with a higher risk of IBS and others with a lower risk of IBS. Studies also are often not considering the placebo/nocebo effect. (2-5) If you have noticed that you get IBS symptoms from caffeine, or if you drink a lot of other drinks that contain caffeine, there’s no harm in reducing or avoiding it (other than some withdrawal symptoms I know some get when they stop drinking coffee). Also think about whether you are subconsciously expecting caffeine to quicken your gut, as this can have an effect. There’s also no real evidence to confirm that caffeine could be helpful for constipation or IBS-C. (1,5) Moderate caffeine consumption is not dangerous, but FDA recommends getting a maximum 400 mg of caffeine per day, or 4-5 cups of coffee to avoid side effects (6). 

Coffee, apart from caffeine can also have effects on gut functions (7). It can be irritating to the stomach and cause heartburn, but it also contains polyphenolic antioxidants, that are linked with numerous health benefits. There is some evidence showing coffee drinking increases the beneficial Bifidobacteria in the gut, but if there is true significance, it is not known yet. It is also not clear whether it is the polyphenols in coffee that are beneficial to gut microbes, or both caffeine and polyphenols. (8)

The effects of coffee and the compounds it contains on the gut-brain connection have also been studied. Coffee and caffeine are stimulating to the nervous system by activating the sympathetic nervous system (fight-or-flight) and increasing blood pressure. However, salivary cortisol (one of the stress hormones) was not increased. (8)

Interestingly, dark roast coffee might be more gentle to the gut than light roast coffee. This is because it is suggested that lower acidity coffee, which includes dark roast coffee, might reduce the risk of heartburn (not so much the risk of diarrhea). Cold brew and espresso are other lower acidity options. (10) I was unable to find studies discussing this, but if you are a coffee lover, feel free to try lower acidity coffee and see if it makes a difference for your gut, and don’t drink coffee on an empty stomach.

ALCOHOL

Alcohol Bottles On A Shelf

While alcohol, if consumed chronically, affects gastrointestinal motility, is harmful for the gut lining, decreases nutrient absorption, and causes inflammation (11), there is no evidence that shows that alcohol causes IBS symptoms, or that avoiding alcohol would improve symptoms.

Alcohol is certainly not something we need, so avoiding it is not bad for us. Of course, on the other hand, moderate consumption is not dangerous, and sometimes perhaps it improves our quality of life. The most common recommendation is to not exceed 1 drink per day for women and 1-2 drinks per day for men (1 drink = 1 small beer or equivalent). One thing to know is that alcohol can decrease the quality of sleep even in small amounts, so since sleep is definitely connected to gut health, this is something to be mindful about. (12)

CAPSAICIN

chili pepper on a white background

This is the substance in hot peppers that causes burning in the mouth. It seems to increase blood flow in the gut, and it has antioxidant properties. (11) When it comes to IBS, occasional use seems to cause IBS symptoms in some, but when used regularly it actually could decrease pain and bloating in IBS patients. This is probably why in Asian patients with IBS, reports of pain and changes in bowel habits are less than in Western IBS patients. Capsaicin also influences the gut microbiota, which has been suggested to be protective of obesity, but whether this would affect IBS is not known.

POLYPHENOLS

Green Tea Being Poured From A Tea Pot To A Cup

Polyphenols are important health promoting compounds found in fruits, vegetables, grains, tea, coffee, and wine. They provide antioxidant effects and other beneficial health effects, e.g. by lowering chronic disease risk. The body absorbs some of the smaller polyphenols, but they mostly end up in the colon where our microbiota ferments them. This is good for the gut microbes, which in turn is good for us, as you well know. Polyphenols are being recognized as a highly important factor in the health of the microbiota, along with fiber. A list of the top 20 highest polyphenol containing foods can be found here. (13) Make sure you eat fruits and vegetables every day!

HISTAMINE

Histamine intolerance can have very similar symptoms to IBS, which is why I wanted to give a bit of information what it is. Read more below in the accordion (30, 36-39).

Histamine is a biogenic amine, an organic compound made from a certain amino acid (amino acids are the building blocks for protein). Histamine has many important functions in the body, such as influencing our immunity and inflammation, digestion, appetite and body temperature, so it is important to understand it is not a toxin, but as with most things, in very high amounts it can cause toxicity. Histamine is stored mainly in mast cells and basophils (white blood cells). Only 5% of histamine comes from food, as most of it is produced in the body. Diamine oxidase (DAO) is responsible for degrading histamine and preventing histamine in food from entering the blood circulation in the gut. The ways in which histamine levels can become increased are: 1. There are problems with the DAO enzyme (needs more research), 2. mast cells are releasing more histamine than they should due to infection, stress, allergens, trauma, or alcohol etc. 3. eating foods that have a very high amount of histamine (like spoiled food).

In histamine intolerance, fermented foods containing histamine, or foods that stimulate histamine release from mast cells (certain vegetables) increase histamine enough to not be degraded by DAO effectively. Typically, intolerance is due to the lack of DAO to degrade histamine, resulting potentially from damage to the lining of the intestines, or genetic predisposition. Alcohol seems to have a DAO blocking effect and some drugs (eg non-steroidal anti-inflammatory drugs (NSAIDs), proton pump inhibitors (PPIs), and antibiotics.) hinder histamine metabolism, which can be problematic.

Excess histamine then gets into the body, which causes an array of potential symptoms, as histamine receptors are found in various places in the body. Symptoms range from bloating, diarrhea, constipation, rash, and swelling, to headache, flushing, nausea, heart rhythm changes, nasal congestion etc. that can happen within minutes of eating a food high in histamines.

Diagnosing histamine intolerance is not simple, as many other diagnoses have overlapping symptoms and should be excluded, including IBS. In fact, there is no good objective measure that defines histamine intolerance.

Foods that contain a larger amount of histamine include fish and seafood, cheese (especially hard and semi-hard cheeses), mushrooms, processed meat, leftovers, fermented foods such as sauerkraut, and sugary beverages. Bacteria have an opportunity to produce histamine in these foods. Our microbiota includes bacteria that both degrade or produce histamine, so problems in the health of our microbiota may contribute to symptoms.

Some studies showing that people with IBS may have higher histamine levels than people that don’t have IBS. Other studies show that symptom severity in IBS correlates with histamine levels in the blood. In IBS, mast cells and gut microbes are likely the source of higher levels of histamine.

The gold-standard treatment for histamine intolerance is a low histamine diet. Also, avoiding drugs that destroy DAO enzyme, and avoiding alcohol are recommended. Over-the-counter DAO supplements may be helpful, although while there is some preliminary evidence that DAO can be helpful in histamine intolerance, some authors note that not enough is known about the risks of using DAO enzymes.

Some studies have shown that supplementation with nutrients needed in making DAO such as vitamin C, copper, and vitamin B6 may be helpful, as well as vitamin D and different flavonols. If a low histamine diet doesn’t provide relief of symptoms, H1R antihistamines may be used. Probiotics that can destroy histamine could in theory be helpful, such as species in the group Bifidobacteria, though no studies exist as of yet.

Antihistamines. Anecdotally I’ve heard of people with IBS trying antihistamines and feeling better. In terms of scientific evidence, H1-antagonists in two studies showed promise in adults with IBS and children with functional GI disorders. However, many more studies are needed to confirm whether antihistamines should be used as a treatment for IBS.

What does all this mean? Should you try to reduce the amount of histamines in your diet? Or in other ways reduce histamine blood levels? This is a relatively new area of interest in IBS. To me, if you clearly notice that some foods cause typical histamine-related symptoms, and it is easy to avoid those foods, you can try to avoid them for awhile. If, however, there are many foods that seem suspicious, avoiding all of them increase the risk of nutrient deficiency.

Remember, that histamine intolerance symptoms overlap in major ways with other GI disorders, and a definitive test is not available. Personally, histamine would be a “line of investigation” I’d consider if many other trials failed. My recommendation is rather to reduce and manage stress (to “help” mast cells) as well as following a diet that aims to keep the intestinal lining in good shape (avoid alcohol, food additives and follow a gut-healthy diet).

Before starting any drug or supplement, like supplemental DAO or antihistamines, speak with your doctor. Drugs have side effects, and supplements that are not evaluated by FDA may contain substances that are not supposed to be there.

FOOD EMULSIFIERS

These are food additives that are used to help water based and fat based components mix, and to improve food texture and stability. Western diet, which is rich in processed foods, is also rich in emulsifiers. For example, foods like ice cream, desserts, margarine, bread etc. often contain emulsifiers. (14)

Five Ice Cream Cones

Our body makes such molecules also (bile salts), but as food additives they may have a negative effect on the intestinal mucus layer, microbiota and inflammation, which are linked to the development of leaky gut, which in turn is connected to IBS. Especially polysorbate 80 and CMC (carboxymethylcellulose) have been identified to be problematic. But, these studies were done on mice, and much further research is needed. (14)

FDA considers all emulsifiers used in food “generally recognized as safe”. If you’d like to avoid emulsifiers, check food labels for polysorbate 80 and CMC, but also lecithin, mono- and diglycerides of fatty acids, carrageenan and guar gum are emulsifiers, though perhaps not worth avoiding (15). As with other restrictions, being rational is important as too many restrictions make life more difficult and can make your diet too restrictive and stressful for good health. That said, cooking and baking yourself is an easy way to limit emulsifiers as well as other food additives.

NON-NUTRITIVE SWEETENERS (NOT SUGAR ALCOHOLS)

Cola In A Glass With Red Straw

These are food additives that provide a sweet taste to food or drink without adding any calories. They have been very popular as you can enjoy your favorite soft drink with the same calorie profile as water. FDA considers them safe at the moment (the safety of food additives are assessed periodically), although there is much controversy surrounding sweeteners. When it comes to the gut, unfavorable changes in the microbiota composition have been observed with many of the sweeteners. There may be concern for intestinal inflammation, as well. (16) Studies have also shown a connection between non-nutritive sweeteners and obesity, which is highly interesting (17).

As with other food additives, we don’t need non-nutritive sweeteners for our health, and avoiding foods with sweeteners is often easier than avoiding many other additives. That said, occasional use is unlikely to cause issues in the average person. Read on about two of the most common sweeteners.

Recently there’s the increasing concern that aspartame may increase the risk of cancer and researchers recommend that children and pregnant women shouldn’t consume it at all. However, this is still highly contested among experts with many explaining that aspartame becomes broken up in the body into molecules that exist in natural foods. One study saw a link to cancer with higher overall intakes, but other studies have not found such a link. (18)

Apparently only one study exists and it found a slightly higher risk of cancer. Potential negative effects on gut microbiota seen in mice (19).

HERBS AND SUPPLEMENTS

It is common to look at herbal remedies to ease gut issues, as they seem more natural than medications. Here I’ve gathered information about the ones I’ve heard have been used for gut health purposes and whether there is any scientific evidence on their efficacy. Since the FDA and EFSA don’t control herbal products, the quality and purity of supplemental products are more difficult to verify. Look for products that are produced in CGMP-compliant facilities and tested for purity and potency, ideally by a third-party organization such as NSF International, U.S. Pharmacopeia, or Underwriters Laboratories.

Also, while we tend to think that natural, food derived supplements and herbal remedies are safe because they come from nature, it is a fact that this is not always the case. Furthermore, many herbs can have drug-herb interactions, which could mean a higher or lower potency of the drugs you are taking, which is undesirable. ALWAYS check with your health care provider if you are interested in herbs to make sure it is appropriate for you.

Below I discuss a few of the more well known herbs and supplements used for IBS.

fennel tea

Iberogast is a German liquid herbal product that contains nine different herbs. It promises to relieve IBS symptoms of most kinds, and there is some evidence that suggests it is safe and effective. (20)

Studies support the abdominal pain-relieving effects of the herb, and in the short term, it seems it can be safe and effective. Peppermint contains menthol and menthone that reduce painful spasms of the GI tract (i.e. it is spasmolytic). The supplement must be enteric coated, otherwise it won’t reach the intestines and will be broken down in the stomach. It is not suitable for people with achlorhydria (reduced stomach acidity) or liver issues. Otherwise, side effects are quite minor, the most common being heartburn. (21)

Turmeric is a root vegetable commonly used as a powdered spice in Asian cooking. It contains a substance called curcumin, known for its antioxidant and anti-inflammatory effects. Curcumin is relatively well researched compared to other herbs, although studies are not necessarily of high quality. These studies are suggesting that curcumin can improve disorders such as metabolic syndrome, type 2 diabetes and Alzheimer’s disease, and can reduce LDL cholesterol. Studies also suggest its utility in inflammatory disorders, such as IBD. For example, in rats with IBD, curcumin was seen to reduce mucosal injury. (22,23)

For IBS, only a handful of studies exist, and in a couple of studies the results showed improvement in quality of life, reduction in abdominal pain (although there was no placebo group) and activation of gut motility, when eaten in a curry. (22,23) In rats, on the other hand, curcumin slowed gut motility. (24). More recently, turmeric has been studied together with fennel in a pilot study, with the results showing a positive change in the quality of life. Another very recent study looked at curcumin with another herb (Boswellia serrata, 500 mg twice daily), and saw that after 30 days, this mixture supported the low FODMAP diet in reducing bloating in people with gut dysbiosis and IBS (25). That said, these studies are mostly preliminary, and many rigorous studies need to carried out before clear conclusions can be made. 

Curcumin is fat soluble, and not very bioavailable. Combining turmeric/curcumin with black pepper (piperine) improves its absorption into the body, and should be taken together with curcumin. Many studies are exploring other methods to improve bioavailability, such as using a complex with phospholipids or as nanocurcumin, and this is already being seen on the market of curcumin supplements. Studies also show that sometimes taking curcumin as turmeric may be more effective than using curcumin supplements. Turmeric/curcumin is quite safe, even in very high doses (up to 8 g of curcumin per day, 1 teaspoon of turmeric contains 200 mg of curcumin). People susceptible to kidney stones and iron deficiency should be cautious with high doses. Curcumin can also reduce blood clot formation, so it is not suitable for people taking medications that affect blood clotting, such as anticoagulants or selective serotonin reuptake inhibitors. (22,23,33-35)

As with all supplements, the purity of curcumin supplement can be questionable. There are no studies on specific supplements. Check with your doctor first, always, also keeping in mind if the supplement contains other herbs, like piperine from black pepper. Many turmeric and curcumin supplements exist, but I’ve simply taken turmeric with a dash of black pepper in a small amount of water (20 ml or so, less than 1 fl. oz). The taste is quite strong, but as a shot it is quick to take. Also, it’s affordable and you can find turmeric powder in any supermarket. Buy in bulk from an ethnic store for a lower price. Some supplements out there are expensive, some are third party tested (tested for purity), some are not vegetarian/vegan. Turmeric also exists as a tea. Take with food.

What is very interesting, is that studies are beginning to show curcumin’s ability to improve anxiety via the microbiome-gut-brain axis, by modifying the microbiome. For example, the beneficial bacteria Lactobacilliand Bifidobacteria increased, and Muribaculaceae that seemed to be most involved in lowering anxiety. Studies so far are done in animal models, so more research is needed to confirm these findings in humans. (26)

Fennel seed oil and its main component anethole have antimicrobial activity, a relaxing effect (spasmolytic) on intestinal muscle and it can reduce anxiety. Also, fennel seed extract may improve intestinal barrier function. In infants, fennel reduced colic without side effects. In IBS patients, two weeks of fennel therapy reduced abdominal cramps and reliance on medication. Together with curcumin, fennel seed oil showed potential to improve abdominal pain and quality of life (42 mg curcumin and 25 mg fennel essential oil 2 capsules twice a day for 30 days, then once a day for another 30 days). However, studies are few and not of high quality, but there also doesn’t seem to be safety risk involved. (27,28) You can also try a fennel as a tea.

Glutamine is an amino acid that has been found to improve the gut mucus layer, helping to reduce gut permeability. The cells of the GI tract use glutamine as energy and if there’s not enough glutamine, the gut epithelial cells can atrophy, which increases permeability. (29) There’s some evidence that glutamine is helpful in Crohn’s disease and after intestinal injury (30).

But, could this be helpful in IBS? A study showed that in people with IBS-D, whose IBS symptoms started after a gut infection, 5 g of glutamine 3 times a day improved the participants’ symptoms after the 8 week study period without adverse events (31). Another study saw that glutamine supplementation (5 g 3 times a day) with low FODMAP diet improved the results of the diet as compared to placebo (whey protein,32). It would have been interesting to see if the trend continued when the low FODMAP-diet moved into phase 2 and 3. No serious adverse effects were seen in these studies.

You’ve reached the end of the lesson, I hope you learned something new and useful! This lesson is meant to be expanded with time, so stay tuned for additions. You can also request for something to be added here and I will gladly look into it – use the contact form in the left sidebar.

You have now completed the “Diet” section of IBSwise. Amazing job! The next chapter is filled with information about perhaps the most important factor behind the evolution of IBS – stress.

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