Bile

Overview

Bile is central to digestion and the body's detoxification system. Made from cholesterol, it's used to carry excreted hormones like estrogen and cortisol out of circulation, and also to emulsify fats in the small intestine. When bile flow falters, estrogen gets reabsorbed (and accumulates), fat-soluble vitamins go unabsorbed, gallstones form, and the gallbladder (where bile is released) spasms or stops contracting. Almost every gallbladder problem traces back to two underlying conditions: low thyroid function and excess estrogen.

Key Points

• The liver excretes estrogen and other hormones into the bile, and fiber is what keeps them from coming back. The liver inactivates hormones by attaching glucuronic acid or sulfuric acid to make them water-soluble. Some leaves through the kidneys, but a large fraction goes into the bile. Without enough fiber to bind it in the gut, the estrogen is reabsorbed and returned to the liver, creating a chronic excess of circulating estrogen and slowing the liver further. Raw carrot, well-cooked oat bran, mushrooms, and bamboo shoots (insoluble fiber) all bind bile and reduce reabsorption.

• Estrogen drives the entire spectrum of gallbladder and bile pathology. Estrogen slows liver metabolism and changes the composition of bile so it tends to precipitate cholesterol, forming sludge and stones. It also causes spasms in smooth muscle, including the duct leading out of the gallbladder, so a stone may be unable to pass. In pregnancy, when estrogen is extremely high, this pattern shows up clearly. The same calcium-deficient, vitamin D-deficient bile that produces gallstones also contributes to stones in the kidneys, calcified arteries, and other soft-tissue calcifications.

• Thyroid and progesterone are the two hormones that make the gallbladder work properly. Ray noticed that people he knew with gallbladder disease were chronically hypothyroid, especially those who ended up in surgery. Progesterone relaxes the gallbladder, while estrogen causes it to spasm. Taking thyroid clears up gallbladder dysfunction quickly and predictably, within a few days fat tolerance often returns and the whole system normalizes.

• Endotoxin damages the gallbladder and corrupts bile. Lipopolysaccharide from intestinal bacteria reaches the gallbladder along with incompletely detoxified estrogen, inflaming the system leading into the gallbladder and the duct leading out. Endotoxin weakens the contractile function of the gallbladder muscle while estrogen causes spasm of the duct. Together they create the conditions for stagnation, stone formation, and acute gallbladder crises in which a stone cannot be expelled or bile builds up under pressure.

• Bile acids are made from cholesterol by the 5-alpha-reductase enzyme family. Bile acids are steroid-like molecules. The same enzyme system that produces dihydrotestosterone and allopregnanolone is required to synthesize them. Drugs that inhibit 5-alpha-reductase, such as finasteride, can therefore interfere with bile acid production as a side effect, which means impaired digestion of fats on top of their effects on hair and prostate tissue.

• Bile acids trigger serotonin production in the gut almost as strongly as endotoxin does. This is one of the strongest mechanistic arguments against very high fat diets, even when the fat is saturated. Every fat-containing meal releases bile, and that bile signal directly stimulates the enterochromaffin cells to make serotonin. People who chase the "saturated-fat-is-perfect" message often miss this, because bile-driven serotonin is independent of PUFA exposure.

• Bile acids interfere with the absorption of protein. When fat intake is high, large amounts of bile gets released, which directly impairs protein digestion. Stacking very high fat with very high protein in the same meal works against itself. This is one of the reasons the roughly 33/33/33 macronutrient split is more sensible than extreme high-fat or high-protein approaches.

• Glycine and taurine are required to produce bile acids and should arguably be classified as essential amino acids. Bile acids are synthesized from cholesterol conjugated with one of these two amino acids. Without sufficient glycine or taurine, bile production fails, and without bile, fat-soluble vitamins (A, D, E, K) cannot be properly absorbed. Most people cannot make enough glycine endogenously to be optimally healthy, and dietary intake is usually low because the muscle meats that dominate Western diets are low in glycine.

• Long-chain saturated fats stimulate bile release and form chylomicrons that route absorption through the lymphatic system. Fats with chain lengths over 14 carbons (palmitic and stearic acid being the main ones) combine with bile acids to form chylomicrons. These bypass the portal vein and the liver's first-pass metabolism, dumping into systemic circulation through the thoracic duct. Shorter fats (under 12 carbons, including coconut oil at 12) go to the liver instead. The lymphatic route is anti-inflammatory and some of these fatty acids directly antagonize the endotoxin receptor TLR4.

• Bitter herbs stimulates bile flow. Gentian, burdock root, dandelion root, wormwood, and traditional formulas like Swedish bitters often increase bile production and the digestion of fats. Bitter receptors exist not just on the tongue but in the stomach, liver, and respiratory tissues, and activating them produces a calming, anti-inflammatory effect through the whole body. These can be useful while the underlying thyroid and estrogen problem is being corrected. However, a lot of these treatments are estrogenic themselves and are more of a short-term plaster rather than an actual fix.

• CCK is what triggers gallbladder contraction in response to fat and protein. Cholecystokinin is secreted when fats and proteins enter the small intestine, and it stimulates the gallbladder to release bile. CCK also activates corticotropin-releasing hormone in the brain, which is why eating fat and protein can turn on anxiety and stress. The opposite peptide, GIP (Gastric Inhibitory Polypeptide), is secreted in response to sugar and produces a calming, insulinotropic effect.

• Without a gallbladder, the answer is to eat less fat, not to compensate. A small amount of fat is needed to absorb vitamin A and vitamin D, but a fatty meal is what triggers the gallbladder reflex, so a fairly low-fat diet with moderate-sized meals works well. People without gallbladders generally do better eating this way. Coconut oil's medium-chain fats do not require bile to be absorbed, but it is still better not to repeatedly trigger reflexes that the missing organ would normally handle.

• Roughly two-thirds of Americans have some form of liver disease, which compromises bile production and downstream digestion. Non-alcoholic fatty liver disease, NASH, cirrhosis, and alcoholic fatty liver are widespread. They reduce the liver's capacity to make bile, detoxify estrogen, and clear endotoxin. A compromised liver means compromised bile, which means compromised fat-soluble vitamin absorption, which feeds back into worse liver function. Tolerance to caffeine is used in some countries as a clinical liver test.

Notable Quotes

"Without exception, the people I've known who've had gallbladder disease, especially surgery, were extremely hypothyroid chronically and that usually goes with too much estrogen that can cause spasms anywhere in the smooth muscles starting with the gallbladder and the duct."

[Ray Peat — How to Fix Your Digestion]

• "Estrogen is the main thing that slows down liver metabolism and changes the balance of components in the bile, tending to create stones."

[Ray Peat — Q&A on Reverse T3, HCG, EMF and Viruses, Boosters, Kid's Vaccines, Lung Failure and More]

"Progesterone relaxes it (the gallbladder). Estrogen tends to cause spasms."

[Ray Peat — Ask Your Herb Doctor: Skin Cancer 3]

"The fiber binds the estrogen which your liver is producing and excreting in the bile, and prevents it from being reabsorbed so immediately you can see a decrease in your estrogen level a day or two after eating a raw carrot."

[Ray Peat — Ask Your Herb Doctor: Heart Part 1]

"Bile has been used very traditionally as an aid to digestion, and they can be dangerous. But I think with moderate use with a meal, for some people, they can improve digestion."

[Ray Peat — Hormone Replacement, Thyroid, Frequent Snacking, Chronic Fatigue Q&A]

"Bile acids actually interfere with the absorption of protein"

[Georgi Dinkov — Why You May Need More Carbs in Your Diet – Interview With Georgi Dinkov]

"Bile acids have been shown to trigger serotonin production in the gut almost to the level that endotoxin will do"

[Georgi Dinkov — Digestion and Mood [Generative Energy #10]]

"Long chain saturated fats stimulate the release of bile acids and the formation of something called chylomicrons to increase the absorption of these saturated fats through the lymphatic system and distribute them around the body."

[Georgi Dinkov — Georgi Dinkov, Brad Marshall on Obesity Causes and Solutions (July 11, 2022)]

Important Things To Consider

High-fat diets cause more gut serotonin, even when the fat is entirely saturated. This is counterintuitive for people who have absorbed the message that saturated fat is universally protective. The bile-serotonin mechanism is independent of PUFA. Saturated fat is still vastly preferable to PUFA, but total fat load matters too, because consuming fat triggers bile release and downstream serotonin synthesis.

Don't go high fat and high protein in the same meal. The bile released to handle the fat will impair the absorption of the protein. This is a practical reason standard dietary advice points toward roughly equal macronutrient distribution rather than extreme ratios.

Choosing the right fat can ease liver burden. Stearic acid and palmitic acid (over 14 carbons) form chylomicrons and route through the lymphatic system. Coconut oil (mostly 12-carbon medium-chain) does not. PUFA does not give the same anti-inflammatory effect at the TLR4 receptor and should be minimized regardless. For practical purposes: butter, ghee, beef tallow, and animal fats from grass-fed sources are the right choices for the lymphatic pathway.

Bile acid salt supplements can be dangerous. While bile salts have been used traditionally as a digestive aid and can help some people when taken in moderate amounts with a meal, they are strong substances and should not be assumed safe for general use. The fact that they help in some cases does not make them benign.

Light, clay-colored stools signal a serious gallbladder problem. This is a deep-seated issue that very often goes with high estrogen. Correcting the underlying liver metabolism with thyroid generally resolves it within days, restoring fat tolerance.

Fasting is not the answer for a poorly functioning gallbladder. Intense fasting protocols are not advisable for gallbladder dysfunction. The actual fix is to address low thyroid and the high estrogen-to-progesterone ratio that is causing the compromised gallbladder.

Low-thyroid people have hair-trigger gallbladders. Even a small amount of fat can trigger a strong gallbladder reaction in someone who is hypothyroid. Increasing saturated fat too quickly in a person with biliary insufficiency can produce nausea, aching, and a feeling of inflammation. The underlying metabolic state needs to be corrected first.

An overloaded glucuronidation pathway pushes more estrogen into bile, where it can be reabsorbed. When the liver's main detoxification routes are saturated, more hormone is excreted through the bile. Without adequate fiber, these hormones simply circulates. Adequate carbohydrate, protein, and B vitamins are needed for the liver to keep up with this work.

5-alpha-reductase inhibitors can suppress bile acid synthesis. Because bile acids are steroid-like molecules made by the same enzyme family as dihydrotestosterone and allopregnanolone, drugs that inhibit 5-alpha-reductase, such as finasteride, can impair digestion in addition to their effects on hair and prostate.

Liver health determines bile quality. With NAFLD prevalence near 67% in the US population, most people are operating with some degree of compromised bile production. Caffeine, vitamin K2, taurine, and glycine are the four substances Georgi most consistently names as protective and restorative for the liver. Aspirin and niacinamide also help by improving glucuronidation and inhibiting fatty acid synthase.