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Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is an intestinal disorder that causes characteristic symptoms including abdominal pain, cramping, diarrhea, and constipation but without any other signs of another condition causing these symptoms.

  • Overview
  • Action Plan
  • Ask The Doctor
  • Read & Watch
  • Success Stories
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The prevalence of irritable bowel syndrome (IBS) is approximately 10-15% in the U.S.,1 and most of them haven’t even been diagnosed officially. IBS is more common in females than males. Symptoms of IBS vary from person to person, ranging from mild to severe. Symptoms of IBS may include:

  • Diarrhea/Loose stools
  • Constipation/painful defecation
  • After-meal fecal urgency
  • Alternation between loose stools and constipation, but usually one predominates the other
  • Abdominal pain, often improved after a bowel movement
  • Gas/Bloating
  • Mucus in stool
  • Heartburn
  • Nausea
  • Exaggerated menstrual symptoms
  • Fibromyalgia symptoms (widespread aches and pains)
  • Symptoms exaggerated with stress

The SAD diet, which is predominantly processed foods and animal products, sets the stage for chronic digestive disturbance and unfavorable digestive health. Digestive muscle cramping, bacterial imbalances, and hormonal triggers from conventional foods eventually lead to chronic discomfort and digestive disturbance. The overgrowth of non-favorable bacteria in the intestines, as well as the overall imbalance of intestinal flora, all seem to play a role. Investigators have noted that the more fiber in one’s diet, the better off they are with their IBS symptoms. For some reason which we don’t fully understand, many with IBS report that they are either sensitive to gluten, fructose, and fructans, which are found in a variety of fruits and vegetables. To resolve this problem nutritionally, not only do sufferers need to eat a healthful Nutritarian diet, but many have to avoid wheat, avoid the high fructose fruits, and make the minor adjustments to get the best result. Most can recover in a few months.

  1. Hungin AP, Chang L, Locke GR, et al. Irritable bowel syndrome in the United States: prevalence, symptom patterns and impact. Aliment Pharmacol Ther 2005, 21:1365-1375.

Action Plan


  • A Nutritarian eating style, focusing on vegetables, beans, fruits, nuts, and seeds should be the foundational approach to addressing IBS, but in some cases, this alone may gradually improve symptoms over time, so be patient.
  • Plant foods contain a combination of soluble and insoluble fiber. Soluble fiber may be especially protective.1 Beans, chia seeds, and steel cut oats are rich in soluble fiber; whole grains (other than oats) contain primarily insoluble fiber.2 Raw vegetables  may need to be introduced gradually. Chew all food to a liquid-like consistency before swallowing.
  • Wheat, dairy, and fructose may be triggers for IBS symptoms.3 If symptoms continue or are not fully resolved by following a Nutritarian eating style, then consider the following:
  • Eliminate gluten and dairy products.
  • Reduce intake of moderate-to-high FODMAP-containing fruits and vegetables, such as apples, pears, and artichokes.4
  • If constipation is the primary symptom, focus on drinking sufficient amounts of water between meals in addition to getting adequate soluble fiber.
  • Avoid caffeine and other stimulants.


  • Dr. Fuhrman’s general supplement protocol for adults (see Vitamin Advisor for details) includes:

  • Additional supplements:

    • Probiotics: IBS is associated with alterations in the gut microbiome.3,5 Studies have reported probiotic supplements reduce abdominal pain, bloating and other IBS symptoms, but further studies are needed to determine the optimal dose and species of probiotics most effective for IBS.6-8

    • Peppermint oil has a natural anti-spasmodic effect on the smooth muscle of the gastrointestinal tract. Studies have reported improvements in abdominal pain and overall symptoms.9 

For supplement recommendations personalized to you, your health condition and goals, visit the Personalized Vitamin Advisor and answer a few questions.


  • Research suggests exercise improves IBS symptoms, possibly by improving alterations in gut motility.10-12

Other Considerations

  • Stress, which may be a contributing factor to IBS symptoms. Meditation could be a helpful stress-reducer, and counseling may help build an overall strategy for dealing with stress.

Find additional help

ONLINE: All members of can search the Ask the Doctor archives for discussions on this topic. Platinum and Diamond members can connect with Dr. Fuhrman by posting questions in the forum. Not a member? Join now.

IN PERSON: Book a stay at Dr. Fuhrman’s Eat to Live Retreat in San Diego, California. With options ranging from one, two and three months (and sometimes longer) you will be under Dr. Fuhrman’s direct medical supervision as you hit the “reset” button on your health. For more information: (949) 432-6295 or [email protected]

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  1. Moayyedi P, Quigley EM, Lacy BE, et al. The effect of fiber supplementation on irritable bowel syndrome: a systematic review and meta-analysis. Am J Gastroenterol 2014, 109:1367-1374. doi: 10.1038/ajg.2014.195

  2. Higdon J, Drake VJ: Fiber. In An Evidence-based Approach to Phytochemicals and Other Dietary Factors New York: Thieme; 2013: 133-148

  3. Chey WD, Kurlander J, Eswaran S. Irritable bowel syndrome: a clinical review. JAMA 2015, 313:949-958. doi: 10.1001/jama.2015.0954

  4. Muir JG, Gibson PR. The Low FODMAP Diet for Treatment of Irritable Bowel Syndrome and Other Gastrointestinal Disorders. Gastroenterol Hepatol (N Y) 2013, 9:450-452. doi:

  5. Rajilic-Stojanovic M, Jonkers DM, Salonen A, et al. Intestinal microbiota and diet in IBS: causes, consequences, or epiphenomena? Am J Gastroenterol 2015, 110:278-287. doi: 10.1038/ajg.2014.427

  6. Hoveyda N, Heneghan C, Mahtani KR, et al. A systematic review and meta-analysis: probiotics in the treatment of irritable bowel syndrome. BMC Gastroenterol 2009, 9:15. doi: 10.1186/1471-230X-9-15

  7. Liang D, Longgui N, Guoqiang X. Efficacy of different probiotic protocols in irritable bowel syndrome: A network meta-analysis. Medicine (Baltimore) 2019, 98:e16068. doi: 10.1097/MD.0000000000016068

  8. Niu HL, Xiao JY. The efficacy and safety of probiotics in patients with irritable bowel syndrome: Evidence based on 35 randomized controlled trials. Int J Surg 2020, 75:116-127. doi: 10.1016/j.ijsu.2020.01.142

  9. Alammar N, Wang L, Saberi B, et al. The impact of peppermint oil on the irritable bowel syndrome: a meta-analysis of the pooled clinical data. BMC Complement Altern Med 2019, 19:21. doi: 10.1186/s12906-018-2409-0

  10. Chey WD, Rai J. Exercise and IBS: no pain, no gain. Gastroenterology 2011, 141:1941-1943. doi: 10.1053/j.gastro.2011.09.030

  11. Johannesson E, Ringstrom G, Abrahamsson H, Sadik R. Intervention to increase physical activity in irritable bowel syndrome shows long-term positive effects. World J Gastroenterol 2015, 21:600-608. doi: 10.3748/wjg.v21.i2.600

  12. Johannesson E, Simren M, Strid H, et al. Physical Activity Improves Symptoms in Irritable Bowel Syndrome: A Randomized Controlled Trial. Am J Gastroenterol 2011. doi: 10.1038/ajg.2010.48

Ask The Doctor

The following are sample questions from the Ask the Doctor Community Platinum and higher members can post their health questions directly to Dr. Fuhrman. (All members can browse questions and answers.)


I have been following a Nutritarian diet for a little over two years. I have been diagnosed with IBS and have occasional bouts with constipation, and the constipation, bloating, and gas have not stopped.

  1. I have been working on diet issues to try and resolve the gas problem. Considering that methane tends to lengthen transit time, would a product like Beano have any effect on alleviating the constipation?
  2. I noticed fructose, high fructose corn syrup, apples, pears etc. on the FODMAPS list mentioned in the IBS webinar. I don’t use added sugar but do eat the fruit on the list. I also use a lot of artificially sweetened breath mints. Could the artificial sweeteners and fruit be responsible for part of the constipation and bloating? Is stevia an acceptable artificial sweetener?

If you still have bowel problems on a Nutritarian diet, then you should be more vigilant avoiding the entire FODMAPS load. Beano is not the answer. The goal is to reduce the FODMAP load significantly, depriving the bacteria of a food source, which will reduce methane production. You should also avoid all polyols- these artificial sweeteners are another source of the problem. Both the fruit and the sweeteners are likely responsible for bloating and constipation. You should avoid all high fructose fruits. You can use stevia occasionally, but not every day.

Remember, for you it is the FODMAP load that is important. Most people can do well giving up the list discussed during the webinar. You should chew each bite very well, making sure you maximize the release of important phytochemicals like ITCs from your greens. You should also add the probiotic. If you continue to have symptoms after a period of a few months, we can reassess.