If you asked the average person to point to their gallbladder, the odds are pretty high they might make a vague indication toward somewhere south of their neck but miss the mark, that is unless they’ve had painful gallstones in the past.
Gallstones are actually quite common, affecting an estimated 25 million people in the US alone, according to the National Institutes of Health.
But most often people have no symptoms. Although most people have no symptoms, some are not so lucky and feel a mix of symptoms including pain in the upper abdomen and back, and nausea. Often, the only long-term way to remedy the problem is with surgical removal of the gallbladder. Women and people over the age of 40 are more likely to develop gallstones as are people with Indigenous American or Mexican ancestry. (See sidebar for more information about gallstones among people with Indigenous American ancestry.)
Higher and to the Right
Gallstones and Indigenous Americans
A few studies have shown that the incidences of gallstones are much higher among those with Indigenous American ancestry — this includes people with Latino ancestry who typically have a mix of European, African, and Indigenous American ancestry.
But why would people with Indigenous American ancestry have a higher likelihood of developing gallstones?
While dietary factors play a role, so too does genetics. This may in part be due to variants in two genes — ABCG8 and TRAF3. A variant in ABCG8 is known to cause a release of excess cholesterol into bile, and a variant in TRAF3 is thought to contribute to increased inflammation in the gallbladder. Both variants were found to be more common among certain populations with Indigenous American ancestry and increase the likelihood of developing stones. It’s possible that the variants conferred an evolutionary advantage for Indigenous people living in the Americas, but modern diets that include more red meat, saturated fats, and sugars undercut that advantage.
Looking at our own data from customers who consented to participate in research, Samantha Ancona Esselmann, Ph.D., a 23andMe Product Scientist, found that Latino participants report higher incidence of gallstones at every age bracket. And again, Latinos typically have some Indigenous American ancestry.
As a side note, Samantha noticed something in the data related to statistics called the “Simpson’s Paradox.” Because 23andMe’s Latino research participants tend to be much younger than our participants with primarily European ancestry, and because gallstones tend to be heavily age-dependent, the first pass at the data seems to show a higher percentage of European participants reporting gallstones. But by controlling for age, Samantha confirmed a much higher incidence of gallstones among Latino 23andMe participants.
Beyond the implications this has for people with Indigenous American ancestry, it’s another important example of how understanding your genetic ancestry can help you better understand your health.
Before diving a little deeper it’s worth understanding a bit about this tiny organ that’s nestled up against your liver. (For those navigating their own body map, this is in the upper right portion of your abdomen.)
The gallbladder helps store bile, produced in the liver, that in turn assists the body in breaking down and digesting fat. In other words, it’s important for digestion. Things can get mucked up in the gallbladder when stones are formed. The formation of stones in and of itself may not result in symptoms but in some cases, these little masses that form, which can be as small as a grain of sand or as large as a golf ball, can block the outlet of the gallbladder causing severe pain. This often happens after a particularly fatty or large meal. In some cases, this sort of gallbladder attack lasts longer than a few hours and is accompanied by a fever and chills. This is often an indication of something more serious and may require surgery to remove the gallbladder.
Going Deeper
So, why do some people develop gallstones, and how do you prevent them? Well like a lot of conditions, your chances of developing gallstones is influenced by both genetic and non-genetic factors.
The good news is that simply maintaining a healthy lifestyle including keeping a healthy weight, exercising regularly, and eating a diet high in fiber, low in unhealthy fats, refined carbs, and sugars can go a long way toward lowering your risk. Your genetics also plays a role.
As part of 23andMe+ Premium, an annual membership with 10+ exclusive reports and features delivered to you throughout the calendar year, we now offer a report that estimates the likelihood of developing gallstones. This report is based on a statistical model that considers 6,950 genetic markers. The model also includes ethnicity and sex to calculate an estimate. The data used in the model comes from 23andMe customers who consented to participate in research.
Taking Action
Understanding more about your genetics can be a good next step in learning about your chances of developing gallstones. Remember to talk with your healthcare provider before making any major lifestyle changes. That said, maintaining a healthy weight, eating a diet that is low in saturated fat, refined carbs, sugars, and getting plenty of exercise can go a long way toward reducing your likelihood of developing gallstones.
To learn more about 23andMe+ Premium membership, go here.
***23andMe health predisposition reports include both reports that meet FDA requirements for genetic health risks and reports which are based on 23andMe research and have not been reviewed by the FDA. The test uses qualitative genotyping to detect select clinically relevant variants in the genomic DNA of adults from saliva for the purpose of reporting and interpreting genetic health risks. It is not intended to diagnose any disease. Your ethnicity may affect the relevance of each report and how your genetic health risk results are interpreted. Each genetic health risk report describes if a person has variants associated with a higher risk of developing a disease, but does not describe a person’s overall risk of developing the disease. The test is not intended to tell you anything about your current state of health, or to be used to make medical decisions, including whether or not you should take a medication, how much of a medication you should take, or determine any treatment. For important information and limitations regarding each genetic health risk report, visit 23andme.com/test-info/.