Diet And Gallstones

Diet is one of the most effective ways to overcome gallstone symptoms. Many people follow the wrong dietary approach, however, in the form of the traditional low-fat, high fibre diet. Rather than making symptoms better, this often makes them worse.

Following a Mediterranean-style way of eating that contains healthy fats, such as those found in olive oil and oily fish is far more beneficial. It’s also important to eat plenty of fruit and vegetables which are rich in vitamin C and other antioxidants.

Gallstones are common

As many as one in six people carry at least one gallstone within their gallbladder. Of these, one in five will eventually experience colicky, upper abdominal pain as a result. The remaining four out of five gallstone carriers may never know they harbour these potential pain-bombs, or may discover they own them as an incidental finding during routine health screening or investigations for another condition. Of those with ‘silent’ gallstones, the annual risk of going on to develop symptoms is estimated at around one in twenty-five.

How gallstones form

Every day, your liver produces between 750ml and 1500ml of bile. This bitter-tasting, green-yellow fluid contains water, bile pigments, bile acid salts, cholesterol and lecithin. The relative concentrations of these substances determine whether or not bile becomes supersaturated, so that some of the dissolved ingredients crystallise out to form stones. This can happen when:

  • The liver secretes excessive amounts of cholesterol
  • The liver secretes low levels of bile salts or lecithin which help to make cholesterol soluble
  • Bile stays too long in your gallbladder so more water is absorbed
  • The gallbladder walls are thickened or inflamed and unable to contract properly.

When bile starts to crystallise, it produces a gel-like suspension of cholesterol crystals or bilirubinate salts known as biliary sludge. These small crystals act as the seed for more crystals to form.

If your gallbladder empties normally, these cholesterol crystals may be ejected along with bile and flushed away. If gallbladder emptying is impaired, however, these tiny grains may clump together, or slowly enlarge to form gallstones.

As the make-up of your bile changes on a daily basis, the growth of a gallstone is a stop-and-start process in which layers slowly build up – rather like a pearl grows around a grain of sand inside an oyster.

Seventy per cent of gallstones consist mainly of cholesterol in the form of cholesterol monohydrate crystals.

Up to thirty per cent of gallstones are mainly composed of bile pigments (in the form of calcium rubinate plus calcium carbonate and calcium phosphate).

Gallstones and low-fat diets

Your gallbladder contracts when food reaches the first part of your small intestines, especially when you eat fatty food. This triggers the release of stored bile which emulsifies fats and breaks them down so they are easier to digest and absorb.

Following a low-fat diet may appear to make sense as this reduces gallbladder contraction. You may be advised to do this if your gallstones are getting pushed into the bile ducts to trigger severe pain. If you aren’t experiencing gallstone pain, however, a diet that is too low in fat can actually increase the risk of gallstones in the long-term.

When you follow a low-fat diet, your gallbladder does not contract as much as usual. Only around 20% to 30% of the bile it contains is squirted into your intestines on a daily basis, instead of the more usual 70% to 80%.

Bile therefore becomes pooled within the gallbladder, water is absorbed and the bile thickens to form a sludge. This reduces the amount of cholesterol and bile pigments that can stay dissolved within the bile and the excess starts to precipitate out. This can trigger the formation of new stones or enlarge those already present. So, rather than going too low on fat, it’s better to concentrate on eating a sensible amount of healthy fats.

Gallstones and monounsaturates

Monounsaturated fats such as those found in olive oil, macadamia nut oil and avocado oil are processed in your body in a way that lowers ‘bad’ LDL-cholesterol while having a neutral effect on your ‘good’ HDL-cholesterol (the one you want more of to protect against heart disease). This has a beneficial effect on the level of cholesterol balance may help to reduce cholesterol gallstone formation.

Gallstones and omega-3s

Omega-3s polyunsaturated fatty acids (found in flaxseed, walnut and fish oils) are converted in your body into substances that reduce the amount of cholesterol secreted into your bile. They also reduce any low-grade inflammation that can thicken the gallbladder wall to reduce its ability to contract effectively.

Gallstones and nuts

Nuts provide healthy polyunsaturated fats, monounsaturates, fibre, vitamins, minerals (including magnesium), antioxidants and substances known as plant sterols that have a cholesterol-lowering action.

A US study followed over 80,700 female nurses for twenty years and found those who ate nuts five or more times per week (including peanuts – a legume – and peanut butter) were 34% less likely to develop gallstones to need gallbladder surgery than those who rarely or never ate nuts. When other factors were taken into account, such as saturated fat intake, weight, smoking status, alcohol and caffeine consumption, eating nuts at least five times a week was associated with a 15% lower risk of needing a cholecystectomy.

A similar study involving male health professionals found that frequent nut consumption (5 or more times per week) was associated with a 30% reduced risk of gallstone disease than men who rarely ate nuts.
As a healthy snack, nuts and nut butters are certainly ones to go for.

Brazil nuts have an exceptionally good cholesterol-lowering action.

Gallstones and vegetarian meals

A plant-based diet provides high levels of fibre, vitamin C, magnesium and plant sterols all of which help to protect against gallstone symptoms. This won’t reduce the risk altogether, but vegetarians are half as likely to develop gallstone symptoms compared with omnivores – their risk of developing gallstones is one in eight, compared with one in four for omnivores.

Just increasing your intake of fruit and vegetables without cutting back on meat also has a protective effect. Vegetable protein, in itself, appears to inhibit gallstone formation. Soy protein in particular has a beneficial effect on cholesterol synthesis in your liver, so the concentration of cholesterol in your bile is reduced, and the rate at which cholesterol crystals precipitate out of bile is decreased.

The US study mentioned above, that followed over 80,700 female nurses for twenty years, also found that, after taking other risk factors into account, women with the highest vegetable protein intake were 21% less likely to need their gallbladder removed than those with the lowest intake. The amount of animal protein and total protein they ate did not significantly affect these results, suggesting that any increased consumption of vegetable protein can reduce the risk of cholecystectomy in women.

Gallstones and fibre

Soluble fibre such as pectins (found especially in apples and carrots) and gums (found in oat bran and soy beans) bind to cholesterol and bile salts in the gut to reduce their re-absorption.

Bran fibre also has an effect on intestinal bacteria in your large bowel, so that when they break down bile acids, they produce less deoxycholic acid – a secondary bile acid that is reabsorbed and makes bile more conducive to stone formation.

Adding 10g to 50g fibre supplements to your diet, every day, can lower the cholesterol saturation of bile within four to six weeks.

Researchers from Harvard looked for any association between fibre intake and the risk of cholecystectomy in almost 70,000 women aged from 35 to 61 years who were followed for 16 years. After taking all other risks factors into account, they found that women with the highest fibre intake were 13% less likely to undergo removal of their gallbladder than those with the lowest fibre intake.

Every 5g increase in total fibre intake reduced the risk by around 6% on average, with insoluble fibre proving more protective than soluble fibre. For those who ate the most fruit and vegetables (a major source of insoluble fibre), the risk of needing a gallbladder removal was 21% lower than those eating the least. Green leafy vegetables, citrus and other vitamin C-rich fruits and vegetables were most protective, along with cruciferous vegetables (members of the cabbage family).

Gallstones and cholesterol-rich foods

The amount of cholesterol you obtain from your diet depends on the amount of animal-based products you eat. Typical diets provide 500mg to 1000mg cholesterol per day, of which the richest sources are liver, caviar, prawns, meats and egg yolk (although eggs also supply vitamins, minerals and lecithin which have beneficial effects so you don’t want to avoid eggs altogether).

The more cholesterol you eat, the more cholesterol gets secreted into your bile – although this partly depends on your genes. Inheriting ‘good’ genes means your liver production of LDL-cholesterol should reduce as  dietary cholesterol intake increases, but this mechanism is faulty in many people. When more cholesterol is secreted into bile than can remain in solution, some cholesterol will precipitate out to seed the formation of new gallstones, or to enlarge any that are already present. It therefore makes sense to limit your cholesterol intake.

Click here to read about the best cholesterol-lowing supplements.

Gallstones and carbohydrates

People who eat the most refined sugar (eg sucrose, fructose) and carbohydrates (eg white bread) have a higher than normal risk of developing gallstones even if they are not overweight.

Researchers from Harvard followed almost 70,000 women aged from 35 to 61 years for 16 years. After taking all other risks factors into account, they found that women with the highest carbohydrate intake were 35% more likely to undergo removal of their gallbladder than those with the lowest carbohydrate intake.

Overall, there is good supporting evidence that cutting back on carbohydrates in general, and following a low glycaemic diet, helps to protect against gallstone disease.

Gallstones and vitamin C

Vitamin C is vital for converting cholesterol into bile acids. It does this by acting as a cofactor for an enzyme (7 alpha-hydroxylase) that regulates the conversion. If vitamin C is lacking, the conversion slows, and the balance between bile cholesterol versus bile acids (which help keep cholesterol dissolved) shifts to promote gallstone formation.

When German researchers looked at the dietary habits of both men and women, they found that taking vitamin C supplements reduced the risk of gallstone disease by 66%. Out of 232 people who regularly took vitamin C supplements, only 11 (4.7%) developed gallstones compared with 156 of 1897 who did not take vitamin C supplements (8.2%).

Another study, in which volunteers booked to undergo surgery to remove their gallbladder (laparoscopic cholecystectomy) took 500 mg vitamin C, four times a day (ie 2g per day in total) for two weeks beforehand, showed the time taken for cholesterol to precipitate out of their bile was significantly longer than in similar patients who did not take vitamin C (7 days versus 2 days). This strongly suggests that regular use of vitamin C supplements may help to reduce cholesterol gallstone formation.

Aim to eat more vitamin C-rich foods and/or consider taking a supplement. Food sources of vitamin C include most fruit and vegetables especially guava, citrus fruit, berries, blackcurrants, capsicum peppers, kiwi fruit and dark green leaves.

Gallstones and magnesium

Magnesium is obtained from beans (especially soy), nuts, whole grains (processing removes most of their magnesium content), seafood and green leaves. Dark chocolate, drinking water in hard-water areas, mineral seasoning salt and yeast are also important sources.

Low magnesium intakes are common and affect an estimated one in ten people. A magnesium-deficient diet has an adverse effect on cholesterol balance and increases the risk of gallstones. This may relate to its role in regulating the movement of fluid and ions in and out of cells, and its effects on muscle dilation and gallbladder contraction.

A US study that followed over 42,700 male health professionals for fifteen years found those with the highest magnesium intake from food (greater than 409mg per day) were 33% less likely to develop gallstone disease than those with the lowest intake (less than 288mg per day). When other factors were taken into account (such as age, weight, smoking, exercise, medication, alcohol, fibre) the protective effect was only slightly reduced to a 28% lower relative risk.

Aim to eat more magnesium-rich foods, and/or consider taking a magnesium supplement.

Click here to read my Expert Health Review of the best magnesium supplements.

Gallstones and artichoke

The succulent leaves and stems of Globe artichoke contain several unique substances with similar liver regenerating properties to milk thistle.

A randomized, placebo-controlled trial involving 20 men with acute or chronic digestive symptoms found that taking 320 mg artichoke extracts increased bile secretion by over 127 per cent after 30 minutes, 151 per cent after 60 minutes and by 94 per cent after 90 minutes.

Artichoke extracts also block the synthesis of excess cholesterol in the liver. Taking artichoke extract for 16 weeks can lower total cholesterol levels by 14% with the effects seen within four weeks.

Gallstones and milk thistle

Milk thistle has also been used medicinally for over two thousand years to treat liver and gallbladder problems, including gallstones. Its seeds contain a powerful mixture of antioxidants which promote liver cell function, including the secretion of bile, by maintaining levels of an important liver antioxidant called glutathione. In women, it also helps the liver metabolise oestrogen more efficiently which may also reduce gallstone formation.

By increasing the amount of bile produced, milk thistle decreases its concentration which may reduce new gallstone formation. Preliminary studies suggest it may even help to shrink cholesterol gallstones by increasing the bile acid pool, but little research has occurred in this area, and it is not possible to say how effective it is.

NB Increased bile flow could lead to jaundice if a stone is obstructing the bile ducts. Seek advice before using these tablets if you have persistent gallbladder pain.



Derived from my book Overcoming Gallstones: Nutritional, Medical and Surgical Approaches, available for Kindle and in paperback

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