Digestive and gastrointestinal problems are not commonly thought of when you mention obstructive sleep apnea. I used to think this way as well until I met Lorraine, a woman in her 30s who was thin and healthy looking on the outside. However, she hated waking up in the mornings due to her severe, throbbing headaches, and felt like she only slept for two hours, despite sleeping eight hours. She also had years of chronic diarrhea, bloating, and stomach cramping that came on just after eating.
She was found to have mild obstructive sleep apnea, but couldn’t tolerate CPAP and dental appliances. After a long discussion and after trying a number of conservative options, she decided to undergo surgery to address obstruction behind her soft palate and tongue.
Three months after surgery, her headaches, fatigue and sleep problems improved significantly, and her sleep study didn’t show any more apneas. What caught my attention, however, was that she reported that all her gastrointestinal problems went away completely.
It’s well known that obstructive sleep apnea is strongly linked to high blood pressure, diabetes, heart attack, and stroke. When I went to the literature, I found only a few studies looking at sleep apnea and gastrointestinal issues and sleep apnea. As expected, the most common condition that came up was acid reflux.
Before I begin describing these studies, it’s important to look at what happens when you’re under chronic stress. Having untreated obstructive sleep apnea or upper airway resistance syndrome can cause a stress response on your body. I had a major revelation when I read Robert Sapolsky’s book, Why Zebras Don’t Get Ulcers. The main concept that I got out of his book was that if you’re being chased by a tiger, that last thing you want to do is to reproduce or digest.
Then there’s a story about a civil war soldier who suffered a major abdominal blast injury, leaving his intestines completely exposed. Doctors noted that when he was in a good mood, the bowels looked pink and vibrant. During painful procedures, the bowels looked dark and dusky. This story supports Zapolsky’s tiger example that during times of acute stress, blood flow and nervous system activation is diverted away from the bowels, in favor of your heart and core muscles, so you can fight or run.
Similarly, people with obstructive sleep apnea will have chronic, low-grade degrees of physiologic stress, diverting blood flow and nutrient supply away from the gut. Now imagine if you ate a meal. The normal digestive processes of acid secretion, bile formation, peristalsis (rhythmic movement of the muscles) and absorption is going to be impaired. Imaging what can happen when you place food in your stomach. It can cause bloating, pain, indigestion, diarrhea or constipation.
Here are 5 gastrointestinal conditions that have documented associations with sleep disturbances or obstructive sleep apnea.
1. Irritable Bowel Syndrome (IBS)
The example I gave in the beginning of this piece is a young woman with IBS. In a small study from Soroka and Ben-Gurion Universities in Israel, researchers found increased sleep fragmentation, 2x higher arousal index, and lower levels of slow wave (deep) sleep in subjects with IBS. Not too surprisingly, 3/6 of the subjects with IBS had OSA. The remainder probably had upper airway resistance syndrome (UARS).
Researchers from Rush University compared sleep quality in patients with inflammatory bowel disease (IBD, Chron’s or ulcerative colitis), irritable bowel syndrome (IBS), and controls. The average AHI was 7-8 vs. < 1 in controls. Thirteen percent of all participants had obstructive sleep apnea. Of note, the arousal index was twice as high for people with IBD and IBS vs. controls.
3. Celiac Disease
Although there are reports of sleep apnea improving after going on a gluten-free diet, a study from the University of Naples found that a gluten-free diet didn’t improve sleep quality scores in celiac patients. In a blog I wrote a while back on celiac disease, I made the observation that every patient I know with celiac symptoms (whether celiac disease, or gluten sensitivity) has small jaws with very narrowed airways.
4. Colon cancer
It’s been shown that lack of sleep or too much sleep ups your risk of colon cancer. In this landmark study from Spain, obstructive sleep apnea was linked to higher rates of cancer (all types). Of note, this increased risk was seen only in men less than 65 years of age. Lower levels of oxygen were found to correlate better with increased cancer risk than the AHI. The most common type of cancer was colon cancer. The other common cancers seen were prostate, lung and breast cancers.
5. Acid reflux
One of the basic tenets of obstructive sleep apnea is its’ strong association with acid reflux. There have been tomes of studies describing how obstructive sleep apnea can aggravate reflux and vice versa. Studies have shown that treating OSA can help reflux symptoms and treating reflux can lower OSA severity scores. Vacuum-like negative pressures created in the chest wall from apneas is a simple explanation for this condition. What comes up is not only acid, but bile, digestive enzymes and bacteria. There are documented reports of pepsin (a digestive enzyme) in middle ear, sinus and lung washings. Imagine what these substances can do to your teeth, especially if you are a mouth breather with lower levels of saliva which has alkaline properties.
Sleep physicians have observed that the most common symptom of jet lag is constipation. Your digestive system is strongly linked with your circadian and sleep patterns. Add to this repeated choking episodes from obstructive sleep apnea or upper airway resistance syndrome and it’s not surprising that we’re finding these associations.
If you suffer from any of the the above conditions, how has treating sleep apnea (using CPAP, dental appliances or surgery) helped? Please enter your response in the area below.