Does reducing sugar intake help prevent nephrolithiasis (kidney stones)?

From the Guidelines

Reducing sugar intake is a crucial step in preventing nephrolithiasis, as it helps lower urine calcium excretion, improves insulin sensitivity, and maintains a healthy weight. To reduce the risk of kidney stones, it is essential to limit added sugars to less than 25 grams (6 teaspoons) per day for women and 36 grams (9 teaspoons) for men, as suggested by general dietary guidelines 1.

Key Recommendations

• Limit added sugars to less than 25 grams (6 teaspoons) per day for women and 36 grams (9 teaspoons) for men
• Avoid sugary drinks like soda, fruit juices, and sweetened teas
• Read nutrition labels and choose low-sugar options
• Replace sugary snacks with whole fruits, vegetables, and unsalted nuts

Reducing sugar intake has several benefits:

1. Lowers urine calcium excretion: High sugar intake can increase calcium excretion in the urine, which is a major component of most kidney stones 1.
2. Improves insulin sensitivity: Reducing sugar intake can improve insulin sensitivity, which in turn reduces calcium and uric acid excretion in the urine.
3. Maintains a healthy weight: Obesity is a risk factor for kidney stones, and reducing sugar intake can help maintain a healthy weight.

In addition to reducing sugar intake, drinking plenty of water (aim for 2-3 liters per day) and limiting sodium intake can further decrease the risk of kidney stone formation 1. The American Urological Association recommends a fluid intake that will achieve a urine volume of at least 2.5 liters daily, and counseling patients with calcium stones to limit sodium intake and consume 1,000-1,200 mg per day of dietary calcium 1. If you have a history of kidney stones, it is essential to consult your doctor about specific dietary recommendations and potential medications to prevent recurrence.

From the Research

Reducing Sugar Intake and Nephrolithiasis

• Reducing sugar intake may help prevent nephrolithiasis (kidney stones) as some studies suggest that high sugar intake is associated with an increased risk of kidney stone formation 2.
• Consumption of sugar-sweetened soda and punch is associated with a higher risk of stone formation, whereas consumption of coffee, tea, beer, wine, and orange juice is associated with a lower risk 2.
• A diet based on adequate intake of calcium and containment of animal protein and salt can decrease significantly urinary supersaturation for calcium oxalate and reduce the relative risk of stone recurrence in hypercalciuric renal stone formers 3.
• The DASH-style diet, which is high in fruits and vegetables, moderate in low-fat dairy products, and low in animal proteins and salt, is associated with a lower relative supersaturation for calcium oxalate and a marked decrease in risk of incident stone formation 3.

Dietary Recommendations

• Restricting dietary calcium is not recommended for stone formers with nephrolithiasis, as it may increase the risk of hyperoxaluria and progressive loss of bone mineral component 4, 3.
• A low-protein, low-salt diet with high hydration is strongly advised in children with cystinuria, and a balanced consumption of fruit and vegetables and a low consumption of chocolate and cola is recommended for pediatric stone formers 4.
• In older patients, dietary counseling for renal stone prevention should consider the particular aspects of aging, including restriction of sodium intake and higher intake of potassium, magnesium, and citrate 4.

Mechanisms of Stone Formation

• The relationship between diet and the formation of renal stones is complex and involves the saturation and crystallization processes in the urine 3.
• Urinary calcium excretion is influenced by other nutrients than calcium, such as sodium, potassium, protein, and refined carbohydrates 3.
• Oxalate absorption in the intestine depends linearly on the concomitant dietary intake of calcium and is influenced by the bacterial degradation by several bacterial species of intestinal flora 3.