Bariatric Surgery FAQ

Gastric Bypass and Kidney Stones

Gastric Bypass and Kidney Stones - Bariatric Fusion

Gastric Bypass surgery is becoming an increasingly popular and safe treatment for weight management and obesity. Roux-en-Y surgery, gastric band, and sleeve gastrectomy are all types of bariatric surgery that are commonly offered to those struggling with severe obesity.

Bariatric surgery offers life-long benefits, however, many people are unaware that malabsorptive surgeries increase the risk of kidney stones.

Studies have shown that 10 years after gastric bypass surgery, there is a 14% increase in the incidence of kidney stones. However, with proper management, kidney stones can be prevented.

In this article, we discuss what kidney stones are, symptoms and how they form after bariatric surgery. We also cover the methods of detecting and preventing kidney stone formation after bariatric surgery.

What This Article Covers:

What Are Kidney Stones?

The kidneys play a role in filtering waste from the body and excreting it through urine. Not only do they filter waste, they help make red blood cells, keep bones healthy, control pH levels in the body, and control blood pressure.

When the kidneys cannot remove certain waste from the body, sometimes there is build up of oxalates, causing stones to form.

Some kidney stones can be small enough that you can pass them without knowing. However, larger stones can cause a number of symptoms, including pain, as they pass through the urinary tract.

Individuals that are at a higher risk of kidney stones are those with a history of them, decreased water intake, high protein diet, obesity, and some medications. Men have also been seen to have an 11% risk when compared to women with a 9% risk.

Gastric Bypass and Kidney Stones

Kidney Stones and Bariatric Surgery

The formation of kidney stones can be a common side effect in malabsorptive bariatric surgeries and less likely in restrictive bariatric surgery, like gastric band.

The higher risk in malabsorptive surgeries, such as gastric bypass, is due to the rearrangement of the gastrointestinal tract. The majority of oxalate absorption happens in the intestines. When a large amount of the intestines are bypassed, higher levels of oxalate can accumulate in the urinary tract. In turn, this increases the risk of stones forming.

Symptoms of Kidney Stones

There are several symptoms that may indicate the formation of kidney stones. Early detection is key in decreasing stone formation, so it’s important to know what to look out for.

Symptoms include:

  • Cloudy urine and strong smell
  • Lower back pain
  • Lower abdomen pain, like a lingering stomach ache
  • Blood in the urine
  • Fever and chills

Preventing Kidney Stones

Unfortunately, when a stone has formed, the treatment is to pass it through the urine. Typically, you are recommended to increase your water intake. There is medication that may be available and if there is sign of infection or serious concern, surgical intervention may be done.

In the long-term, kidney stones can increase the risk of kidney disease as well as reoccurring stones. Taking preventative action to avoid kidney stones is going to be essential in preventing long-term issues. Gastric bypass forums are a great resource for people dealing with similar problems.


Changes in diet will depend on the type of kidney stones you have. The most common kidney stones form from oxalates after bariatric surgery, which can come from the food we eat.

High levels of oxalate can come from foods, like peanuts, spinach, beets, chocolate, and sweet potatoes. If kidney stones are forming due to high oxalates, it is advised to monitor your intake of these foods in order to reduce the risk.

Some people believe calcium is the enemy in this case, but this is incorrect. Calcium binds with oxalates. So, for oxalates that are not adequately absorbed after bariatric surgery, the binding of calcium can move things along. Eating calcium-rich and high oxalate foods in the same meal can cause binding to happen in the stomach, resulting in lower risk of oxalate stones. Do not decrease calcium intake as this can actually increase your risk of kidney stones.

Low or excessive vitamin intake can increase the risk of kidney stones. The correct balance of vitamin and mineral intake after surgery can play a role in stone prevention.

Limiting sodium intake can also help. Not only does sodium contribute to kidney stones, but it also increases blood pressure. This has a negative effect on the positive long-term effects of bariatric surgery.


Staying hydrated is the best way of keeping things regulated. Water will flush out the kidneys and dislodge buildup.

For bariatric patients, it is recommended to increase fluid consumption between meals and not with meals. Be wary of certain beverages that contain high oxalates, such as coffee, tea, and soy milk.

Early Detection

Early detection can make all the difference when it comes to preventing kidney stones. Catching a stone early will give you the chance to make the necessary diet and lifestyle changes to keep things manageable.

Ignoring the signs of kidney stones can result in worsening symptoms and long-term complications.


If you are considering bariatric surgery, it is important to know the risks and complications that may occur after surgery. It is essential to follow preventative measures for gallstones, kidney stones, and vitamin and mineral deficiencies.

With the proper lifestyle choices, dietary and supplement regimens, you can decrease the risk of symptomatic kidney stones and other complications in order to maintain quality of life.

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**This blog is for information and education purposes only. This information is not intended to substitute professional medical advice, diagnosis, or treatment. Please consult with your physician or another qualified health provider with any questions in regards to a medical condition.

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