Upset stomach is an umbrella term that often describes general GI discomfort. While the stomach may be the primary issue, other areas of the digestive tract cause problems as well. Symptoms include abdominal pain or discomfort, bloating, nausea, or a full feeling after eating.

Technically speaking, the proper way to refer to these issues when they’re persistent is a functional gastrointestinal disorder(FGID). This term more accurately captures the scope of the problem. Theoretically, any organ of digestion may be the culprit.

Unfortunately, doctors don’t always find an organic cause of FGID in people. The stomach seems fine, the pancreas and liver work well, and there’s nothing to see in the colon.

However, there’s a big blind spot when it comes to a potentially hidden cause of FGIDs. Since there’s no direct connection between the musculoskeletal system and digestion, no one looks for muscle imbalance as a cause of FGID.

But, the abdominal cavity is packed pretty tight with organs, fascia, muscle and other tissues. As a result, tightness, weakness or general irritation of muscle may impede GI function.

Interestingly, a recently published report in children found that a common culprit in lower back pain may have a role in FGIDs.

Upset stomach in children with no known cause

In this observational study, children aged 2-18 presenting with an FGID and no organic cause received massage therapy. The massage therapist assessed the children for a tight psoas muscle. Those with a tight psoas received treatment to address psoas tenderness and tension.

The psoas muscle is a postural muscle that flexes the hip. In addition, it also cradles the organs of digestion.

A total of 122 children underwent treatment with 96 completing it and achieving normal psoas tone, 16 stopping treatment, and 10 continuing past publication. Of the 96 who completed treatment, complete resolution of digestive symptoms occurred in 88(92%). Abdominal pain, nausea, reflux, vomiting, and bowel upset were the predominant symptoms that resolved.

Long term follow up indicated that 75% remained symptom free, with the remaining seeing some level of sustained improvement. Consequently, in those who saw a recurrence of symptoms, stretching the psoas provided relief for many, and follow-up treatments were necessary for some. All 10 of the patients still receiving treatment saw improvement.

The average number of treatments for those who saw resolution was 5.

Conclusion

The findings of this paper are interesting and provide evidence that musculoskeletal issues may play a role in causing upset stomach. Therefore, it’s a good idea to consider massage therapy in those with FGIDs with no organic cause.

However, this brings up a few considerations. First, since this is an observational study, we can’t state tightness in the psaos causes FGIDs. But, in those who have no known cause and see no resolution of symptoms, massage therapy may be a useful approach with limited problems.

Second, if a tight psoas does cause FGIDs, how does it do this? A couple of suggestions in the paper include:

• Inflammation of the irritated psoas may impair nerve function in the gut
• A tight psoas may obstruct blood vessels and nerves of the inferior mesenteric artery and ganglion
• A tight psoas may manifest as a product of stress
• Since there is no control group, it could be placebo

An alternative to these suggestions is that manual manipulation of the psoas also stimulates the digestive tract. As you can see from this image, the psoas sits behind the organs of digestion:

Given this orientation, you cannot palpate the psoas without manipulating the colon and small intestine. Therefore, it may be stimulation of the digestive structures that improves upset stomach, and not the psoas.

Regardless of how it works, addressing a tight psoas may be a useful approach in those with an FGID of unknown origin.