I have been practicing intermittent fasting for 2 years, following the 16:8 method. This means I don't eat anything or drink calorie-containing, especially sugary, beverages from 8 PM until 12 PM the next day. In other words, I haven't had breakfast for 2 years straight. Many people often ask me if I'm not afraid of getting gallstones from skipping breakfast for so long. It's hard to explain in just a few words, so today, let's delve into this issue thoroughly.
Let's conduct an in-depth analysis using images, starting with the gallbladder and bile.
The gallbladder is a small, pear-shaped organ located beneath the liver. Bile produced by the liver is stored in the gallbladder. Eating stimulates the gallbladder to contract, squeezing bile out through the bile ducts, passing through the pancreas, and then entering the small intestine to help digest fats.
Bile contains water, cholesterol, bile salts, lecithin, and bilirubin. Cholesterol is a precursor to bile salts. Under the action of cholesterol 7-alpha-hydroxylase, cholesterol is converted into cholic acid, which then combines with glycine or taurine to form bile acids. These acids combine with sodium or potassium to form bile salts. Bile salts and lecithin have both lipophilic and hydrophilic groups, allowing them to act like surfactants, wrapping and dispersing fats in food. This makes it easier for pancreatic enzymes to bind to and break down fats for absorption.
Used bile salts are absorbed into the blood from the terminal ileum and re-enter the liver for bile synthesis.
It is essential to explain this process in detail because any issue at each step can potentially lead to gallstones.
Gallstones are precipitates of certain components of bile, with cholesterol gallstones accounting for about 75%, black pigment stones for 20%, and brown pigment stones for 5%.
The higher the concentration of cholesterol or pigments in bile, the more likely gallstones are to form. Bile salts help dissolve cholesterol and pigments, thus inhibiting the formation of stones. Therefore, the proportion of various components in bile is crucial.
Not eating breakfast means prolonged fasting. Without food intake, the gallbladder does not contract, and bile remains in the gallbladder for an extended period. The gallbladder absorbs water from the bile, increasing the concentration of cholesterol and other components.
In a 1981 study, it was found that among young women with gallstones, the proportion of those who skipped breakfast was higher compared to those without gallstones. This gave rise to the notion that "skipping breakfast promotes gallstones." You'll find that almost all related popular science references cite data from this study.
However, it's difficult to find academic research linking gallstones to breakfast after this point. The 1981 study had a small sample size, and its results were not very conclusive. For example, they found this difference only in young women and not in older women. Additionally, the study did not analyze variables such as the dietary structure, genetic background, and lifestyle habits of these young women. Simply put, the evidence is very insufficient, and it is completely unfounded to conclude that "skipping breakfast leads to gallstones" based on this study.
In fact, whether in textbooks or publicly published academic papers, breakfast or fasting is not considered a major risk factor for gallstones. The recognized risk factors are gender, age, pregnancy, genetics, diabetes, dyslipidemia, obesity, and overnutrition.
Factors That Contribute to Gallstones
Gender is an important factor in gallstone formation. Across all age groups, women have a higher prevalence of gallstones than men. Before age 50, the prevalence of gallstones in women is two to three times higher than in men. Pregnancy is another risk factor for cholesterol gallstones, with the risk increasing with the frequency and number of pregnancies. These factors are related to sex hormones. Estrogen increases cholesterol secretion and decreases bile salt secretion, while progesterone reduces gallbladder emptying. Both of these factors promote stone formation. Women undergoing hormone replacement therapy or taking contraceptives are also more likely to develop gallstones for the same reasons.
Older adults are 4 to 10 times more likely to develop gallstones than younger individuals. This is because the activity of cholesterol 7-alpha-hydroxylase decreases, making cholesterol less effectively converted into bile salts.
The role of genetics should not be underestimated, with approximately 25% of the risk of gallstones being genetically determined. For example, mutations in the gene for liver cholesterol transport protein ABCG8 increase the likelihood of developing gallstones.
The proportion of gallstones is higher in diabetes patients. Even without diabetes, individuals with high insulin levels are more likely to develop gallstones. This is related to insulin resistance, as it leads to gallbladder motility disorders. When bile is not effectively expelled, it becomes concentrated, facilitating stone formation.
Other risk factors include obesity, rapid weight loss, high cholesterol (non-HDL cholesterol), and lack of exercise. All these factors are related to an increased concentration of cholesterol in bile.
Therefore, instead of worrying about whether you eat breakfast, you should be more concerned about whether you have insulin resistance, whether you are overweight, if your LDL cholesterol is high, whether you should continue taking hormone medications, and whether you sit for long periods each day.
How to Reduce the Risk of Gallstones?
Supplementing with Vitamin C
Vitamin C can increase the activity of cholesterol 7-alpha-hydroxylase in bile, promoting the conversion of cholesterol into bile acids.
It's beneficial to consume nuts in moderation each day because the unsaturated fatty acids in nuts can inhibit the formation of cholesterol stones. Additionally, the fiber in nuts can promote intestinal health, thereby aiding in the recycling of bile salts.
Drinking coffee is also highly beneficial for reducing the risk of gallstones. The active ingredients in coffee can stimulate the release of cholecystokinin, enhancing gallbladder contraction and improving gallbladder mucosal function. Coffee can also promote the recycling of bile salts in the intestines, thereby diluting and dissolving cholesterol. In other words, coffee can reduce the risk of gallstones from various angles.
Engaging in regular exercise, gradual weight loss (less than 1.5 kg per month), reducing sugar intake, and consuming foods high in fiber and calcium are lifestyle changes that can help reduce the risk of gallstones. As for the relationship between fasting and gallstones, there is currently no consensus.
On one hand, prolonged fasting can increase the concentration of cholesterol in the gallbladder. On the other hand, fasting can reduce insulin resistance, adjust intestinal function to promote bile salt recycling, and help in weight loss, all of which can inhibit stone formation. Therefore, more research data is needed in the future to make a definitive judgment.
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