Decreasing the chance of kidney stones

Statistics tell us that roughly one in ten people will have an episode of kidney stones in their lifetime. Most worryingly, however, the number has more than doubled in the past 50 years. Are you one of those people at higher risk and if so, how can you reduce that risk?

Pam Stuppy

As with many other conditions, some of the variables that increase kidney stone risk are beyond our control – such as genetics, aging, and medical issues that affect nutrient absorption, such as: B. Crohn’s disease. Many other risk factors can, however, be counteracted or changed by lifestyle habits.

It seems that the possibility of kidney stones increases when a person has diabetes / insulin resistance, gout, hyperparathyroidism, significant belly fat, metabolic syndrome, conditions that decrease nutrient absorption, a recent history of rapid weight loss (causing increased uric acid excretion). is overweight / obese and / or has had gastric bypass surgery.

The risk is also higher if a person has acute or chronic low fluid intake, high sodium intake, or hypertension, is taking drugs that increase the risk, has low dietary calcium intake, and is taking high doses of extra calcium (especially with Postmenopausal women). and / or anyone who takes high-dose additional vitamin C (> 1000 mg / day).

There are two main types of kidney stones. One is mainly made up of calcium and oxalates, while the other is mainly based on uric acid. Calcium oxalate stones are the most common type. If the urine in any of these substances is consistently high, the risk of stone formation increases. This is excessive when the person is dehydrated as the urine is more concentrated.

So if high extra calcium intake can lead to kidney stones, how can low dietary calcium intake also increase the risk? Because calcium is part of the body’s “electrical system” that keeps our heart and other vital organs functioning, the body has a mechanism that precisely controls the amount of calcium in the blood.

It does this with two hormones – parathyroid hormone and calcitonin. When the body senses low calcium availability, it signals the release of parathyroid hormone, which then begins to extract calcium from the bones. When the level of calcium in the blood rises to a sufficient level, calcitonin is signaled to close the calcium tap in the bones.

However, there is often some excess calcium in the blood, which the kidney then fine-tunes by sending the extra into the urine. This increased calcium in the urine can then increase the risk of kidney stones if it occurs regularly due to persistent inadequate dietary calcium intake. The process also lowers bone density, which is never a good result. Low dietary calcium intake can also increase the amount of oxalate in the urine.

The message here is to get enough calcium from your diet and stay well hydrated. Note that when there is a high calcium intake, the kidneys do the same balancing act with the excess calcium, so that consuming sufficient sources of calcium through food is better than with high-dose food supplements.

Oxalates are compounds found in a number of healthy foods – such as fruits, vegetables, beans, nuts, seeds, and whole grains. They’re also in tea, chocolate, and some beers. Oxalates can bind to excess calcium in the urine and form calcium oxalate stones.

Avoiding or limiting healthy foods containing oxalates in the diet would mean losing all of the amazing nutrients found in those foods. The alternative is to get some calcium from the diet for meals that contain oxalates. These oxalates then bind to some of the calcium and are less likely to cause a problem with stone formation. Increasing dietary intake of citrate, magnesium, and potassium can also help reduce the risk of stones – think, food sources are not dietary supplements.

Uric acid is a by-product of some protein foods like meat, poultry, and fish. A high intake of these can increase uric acid levels in the urine. These increased non-dairy animal proteins can also contribute to a more acidic environment in the body, which can increase the risk of kidney stones by increasing the excretion of calcium and uric acid in the urine and contributing to some dehydration caused by increased urine output .

Excess protein intake due to the use of extra protein can do the same thing. The balance between adequate but not excessive intake of non-dairy animal protein and higher intake of fruits and vegetables (which can contribute to a more alkaline environment) can reduce the risk of kidney stones.

High sodium intake can lead to increased calcium excretion. Research suggests that high blood pressure is a negative factor for kidney stones too. Due to its lower sodium content, higher intake of fruits and vegetables, adequate calcium, and moderate intake of animal protein, it has been found that a DASH diet can potentially lower kidney stone risk. Research is currently investigating possible positive contributions from gut microbes to reduced risk of stones. Eating a healthy high-fiber diet seems like the best way to promote beneficial gut microbes.

Studies suggest that changes in acid-base balance, urinary excretion of calcium, uric acid, and citrate are associated with insulin resistance / diabetes, overweight / obesity, metabolic acidosis, a history of bariatric surgery, and an overall high intake of fructose Sweetened drinks are linked and a diet that is high in other refined sugars.

Additionally, being overweight or obese increases inflammation and oxidative stress, both of which can increase kidney stone risk. These reactions increase concerns about long-term health problems such as an increased risk of myocardial infarction, diabetes, and chronic kidney disease progression.

Note that some drugs can increase calcium and uric acid in the urine. Examples would be some diuretics, antibiotics, epilepsy drugs, weight loss drugs, and others. Ask your pharmacist if any of your drugs increase your risk of kidney stones.

So, make a note of all risk factors for kidney stones and consider what steps you can take to reduce this risk to both short and long-term health.

Pam Stuppy, MS, RD, LD is a registered, licensed nutritionist with nutrition counseling offices in York, ME and Portsmouth, NH. She has also been a nutritionist for the Phillips Exeter Academy, hosting workshops at the national level, and providing guidance on sports nutrition. (For more information on nutrition, some tips on healthy cooking and recipe ideas, visit

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