- The study found that the risk of gallstones increased with the increase in BMI, and when BMI levels were higher than a certain level, vegetarians had a higher risk of gallstones than non-vegetarians.
- The incidence of gallstones was positively correlated with the intake of starch and added sugar in the diet, and even a small amount of alcohol consumption could increase the risk of the disease in women.
- There was no significant difference between the four vegetarian patterns and the formation of gallstones; the older the age, the higher the risk of gallstones.
As medicine explores the field of health, researchers have found that meat has some kind of negative effect on the human body, so many people have started to follow the vegetarian diet pattern for the sake of health care.
However, a new problem has arisen-people who have been vegan for a long time have developed gallstones. Is this phenomenon true or alarmist?
Cause of gallstones
Excessive saturation and crystallization of cholesterol and bile pigment, cholestasis in the gallbladder do not empty, is the cause of gallstones.
When it comes to gallstones, we have to understand the relationship between bile, liver and gallbladder.
The liver is responsible for the secretion of bile, which is discharged through the common hepatic duct into the gallbladder for storage. When the fat we ingest reaches the duodenum (the upper part of the small intestine), endocrine cells in the duodenum release chemical signals (cholecystokinin) to the gallbladder, which receives the signals and starts to contract. Bile is released through the common bile duct to the small intestine to facilitate digestion of fat and absorption of fat-soluble vitamins.
Bile is composed of bile acids, bile salts (chemicals that combine bile acids with two amino acids-glycine and taurine), endogenous cholesterol (secreted by the liver), lecithin, and bile pigments (red blood). Cell degradation products).
If the liver secretes too much cholesterol, or because of liver damage and other diseases resulting in too much bile pigment, consumption can not be deposited in the gallbladder, it is easy to crystallize into a lump, that is, gallstones.
If Cholecystokinin release blocked, it will lead to bile can not be emptied in time, stagnation in the gallbladder makes bile concentration further increased, but also easy to induce gallstones. [1-3]
Gallstones and BMI
Studies have shown that vegetarians have a higher risk of gallstones when their BMI exceeds 22.4 than non-vegetarians
Could a vegetarian diet lead to gallstones? Scientists at Oxford University did a related study. The study followed nearly 50,000 vegetarians and non-vegans for 14 years, recorded their indicators and analyzed them, and finally reached the following conclusions: 
- Of the nearly 500,000 subjects, 1,182 were diagnosed with gallstones (2.4%).
- The prevalence of gallstones increased with BMI, both for vegetarians and non-vegetarians.
- Vegetarians have a higher risk of gallstones after a BMI of 22.4 or higher than non-vegetarians. When BMI was between 18.5 and 22.4, vegans and non-vegetarians had a similar risk of gallstones. Vegans have a lower risk of gallstones when BMI is less than 18.5.
- The risk of gallstone disease is not significantly correlated with the intake of energy, fat and protein, but will increase with the increase of the intake of starch.
- The risk of gallstone disease increases with the increase of added sugar intake.
These findings, however, are based on the fact that gallstones already show symptoms. You know, some people can get gallstones without any symptoms, unless they are tested by ultrasound, CT, MRI, etc. So the Oxford study is incomplete. Let’s look at another study.
A research group in Taiwan examined the relationship between vegetarianism and gallstones. The study lasted for 3 years and observed 1,721 subjects of vegetarian habits. Besides recording and analyzing their various indicators, ultrasound detection was also used to diagnose the occurrence of gallstone disease.
- Of the 1,721 subjects, 141 were tested for gallstones (detection rate of 8.2%).
- The older you are, the higher the risk of gallstone disease.
- For women, even small amounts of alcohol increase the risk of gallstones.
- The higher BMI, the greater the risk of gallstones.
- There was no difference in the risk of gallstones in the four vegetarian diets.
It seems that the vegetarian diet is not as healthy as we thought.
Both studies have confirmed that the risk of gallstones increases with the increase in BMI, and the first study found that the risk of gallstones for vegetarians is higher than that for non-vegetarians as BMI approaches the upper limit of health (23.9). Why is that?
In fact, a vegetarian diet does not necessarily mean a healthy BMI.
Vegetarian diets emphasize the lack of animals and animal-derived ingredients on the plate, and do not exclude foods high in fat (especially saturated fatty acids), sugar and calories, such as potato chips, wine, cakes and cookies.
Plus, a vegetarian diet doesn’t mean a healthy diet. A vegetarian diet can also be low in fiber and high in refined starches, such as rice and fine flour lacking in whole grains, vegetable or fruit juices instead of whole fruits and vegetables, and removing husks from starchy vegetables such as potatoes.
All of these diets set the stage for BMI and body fat to slowly exceed the normal range.
As for the prevalence of gallstones, both studies did not give a reason for the increase in BMI. However, other studies have confirmed that excessive body fat, especially abdominal fat, can cause excessive secretion of endogenous cholesterol, leading to excessive cholesterol in the gallbladder, and thus precipitate and crystallize, eventually forming stones. 
For vegans who aim to lose weight, there is no guarantee of absolute safety. They may turn off fatty foods to reduce their energy intake. If there is no stimulation of dietary fat, the duodenal secretion of cholecystokinin will be insufficient, causing the bile to be difficult to empty, stagnate in the gallbladder and gradually form stones.
Studies have shown that losing more than 1.5kg a week can increase the risk of gallstones.  
How to prevent and manage gallstone disease?
From a preventive point of view, both vegetarians and non-vegetarians should maintain a balanced daily intake of nutrients, natural dietary fiber, regular exercise, ensure good quality sleep and avoid long-term high-intensity stress.
For those who need to lose weight, it should be under the guidance of professionals, with a scientific approach to gradually achieve the goal of weight loss, to avoid the rebound caused by excessive weight loss and repeated weight loss.
From the point of view of treatment, whether symptomatic patients or symptomatic patients, as long as they have gallstone disease, we should strictly abide by the digestive physician’s treatment, to avoid a gradual deterioration of the condition.
Nutrients that vegetarians need to supplement.
1. Vitamin B12.
As it is mainly found in meat, it is not available to vegetarians (especially veggies) on a daily basis and should be supplemented with a reliable vitamin B12 supplement under the guidance of a nutritionist.
Although it exists in both meats and plants, the absorption and utilization of iron in meats is relatively high. So vegetarians can add more vitamin C-rich ingredients to their diet because vitamin C helps iron absorption. Vitamin C is widely found in fruits, vegetarianism need not worry about the lack of the body, but do not use fruit juice to replace the whole fruit.
Egg vegetarians eat enough calcium to meet their needs, but veggies are at risk for calcium deficiency. In the selection of plant source calcium, we should also frequently select the absorption of relatively high utilization of food materials, such as kale, Chinese cabbage, green radish and so on. In addition, every day also need to bask in the sun, help the body to synthesize vitamin D, to promote the absorption and utilization of calcium.
2. Mahan LK, Raymond JL. Krause’s food & the nutrition care process.; 2017.
3. Gropper S, Smith J, Carr T. Advanced Nutrition And Human Metabolism. 6th ed. Belmont: Wadsworth; 2013.
4. McConnell T, Appleby P, Key T. Vegetarian diet as a risk factor for symptomatic gallstone disease. Eur J Clin Nutr. 2017, 71 (6): 731-735. Doi:10.1038/ejcn.2016.252.
5. Chen Y, Chiou C, Lin M, Lin C. The Prevalence and Risk Factors for Gallstone Disease in Taiwanese Vegetarians. PLoS ONE. 2014, 9 (12): E115145. Doi:10.1371/journal.pone.0115145.
7. Tsai C, Leitzmann M, Willett W, Giovannucci E. Prospective study of abdominal adiposity and gallstone disease in US men. Am J Clin Nutr. 2004, 80 (1): 38-44. Doi:10.1093/ajcn/80.1.38.
8. Bj? Rntropn P. International Textbook Of Obesity. Chichester: John Wiley & Sons; 2001.
9. EASL Clinical Practice Guidelines on the prevention, diagnosis and treatment of gallstones. J Hepatol. 2016, 65 (1): 146-181. Doi:10.1016/j.jhep.2016.03.005.
10. Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. J Acad Nutr Diet. 2016, 116 (12): 1970-1980. Doi:10.1016/j.jand.2016.09.025