Gut Microbes and Cushing’s Syndrome
We’ve noted in prior posts that gut microbes play an essential role in treating Cushing’s syndrome with lignans and melatonin. Specifically, without the right mix of bacteria in the gut, the body cannot metabolize lignans into the substances needed for treating Cushing’s syndrome. In fact, it is our belief that in most cases where lignans and melatonin treatment fails to show improvements in the syndrome, this is the reason. So, replenishing the gut microbe using probiotics is essential for a successful treatment outcome, especially for dogs recently treated with antibiotics, indoor dogs and dogs that don’t enjoy a varied diet.
In this post, we wanted briefly to highlight research that shows an altogether different connection between the microbes in an animal’s gut and Cushing’s syndrome. Specifically, whether differences in the gut microbe can themselves contribute to or worsen Cushing’s syndrome. To shed light on this question, researchers obtained and compared stool and blood samples from both healthy and Cushing’s human patients. Their results were published in an article in the journal Frontiers in Endocrinology.
The stool samples revealed significant differences in the microbial populations in Cushing’s patients compared to healthy patients. Specifically, Cushing’s patients had decreased diversity of gut microbes, and the microbes that were present were significantly different than those present in healthy patients. Cushing’s patients had higher concentrations of bacteria (Proteobacteria) found, in other studies, to play a role in causing insulin resistance and other features of metabolic deterioration and to be linked to obesity and diabetes (type 2 diabetes mellitus). Cushing’s patients also had more of a bacteria (Escherichia-Shigella) that has previously been associated with inflammation, insulin resistance and increased cardiovascular risk. Indeed, the study found that higher levels of both those bacteria were correlated with greater likelihood of a Cushing’s patient also having metabolic abnormalities (such as insulin resistance and diabetes).
By contrast, higher concentrations of Firmicutes and Lachnospira bacteria were associated with lower levels of metabolic syndrome in Cushing’s patients. (Our probiotic contains five different strains of Lactobacillus, which is a well-studied genera of Firmicutes. We do not include any Lachnospira, as other studies have found those bacteria to contribute to diabetes.) Other studies of a range of Firmicutes bacteria have also found it to lower metabolic risks, including reductions in prediabetes, diabetes and obesity, and increased insulin sensitivity and energy expenditure.
As expected, the blood work revealed that the Cushing’s patients had higher levels of the diabetes marker HbA1C (commonly known as “A1C”) and triglyceride levels and lower HDL cholesterol (the “good cholesterol”) levels. Cushing’s patients also had higher blood pressure levels. The connection between Cushing’s syndrome, metabolic conditions and hypertension have been well-established by this point, and we have long strongly recommended monitoring Cushing’s dogs for signs of diabetes or other metabolic disorders and of hypertension.
Key Takeaways
This is one of many studies that shows the importance of tending to your dog’s (and your own!) gut microbes, whether they have Cushing’s syndrome or not. But for those with Cushing’s syndrome or that are susceptible to it, such as aging dogs, it is especially important. Whether changes in the gut microbiome are caused by Cushing’s syndrome or vice versa has not yet been established. And while the research is not nearly advanced enough to specify which specific strains of bacteria are best for staving off Cushing’s syndrome, metabolic disorders and hypertension, we can glean from this study that, in general, the more diversity of bacteria within the gut, the better. You can improve your dog’s microbiome with the same sources of probiotics that can help humans–probiotic supplements, yogurt (just make sure the yogurt contains live or active cultures and is unsweetened (including with artificial sweeteners)) and other fermented foods and fresh fruits and vegetables of all kinds.