Abstract
Bariatric surgery (BS) is one of the most common and efficient surgical procedures for sustained weight loss but is associated with long-term complications such as nutritional deficiencies, biliary lithiasis, disturbances in bone and mineral metabolism and an increased risk of nephrolithiasis, attributed to urinary metabolic changes resultant from low urinary volume, hypocitraturia and hyperoxaluria. The underlying mechanisms responsible for hyperoxaluria, the most common among all metabolic disturbances, may comprise increased intestinal oxalate absorption consequent to decreased calcium intake or increased dietary oxalate, changes in the gut microbiota, fat malabsorption and altered intestinal oxalate transport. In the current review, the authors present a mechanistic overview of changes found after BS and propose dietary recommendations to prevent the risk of urinary stone formation, focusing on the role of dietary oxalate, calcium, citrate, potassium, protein, fat, sodium, probiotics, vitamins D, C, B6 and the consumption of fluids.
Highlights
Obesity is one of the most important worldwide public health challenges predisposing to severe comorbidities such as diabetes mellitus, cardiovascular disease, cancer, sleep apnea and hypertension [1].Considering the difficulties regarding diet therapy as a long-term control of morbid obesity, bariatric surgery (BS) translated into an efficient method for sustained weight loss [2].BS procedures comprise restrictive techniques like gastric banding and sleeve gastrectomy, malabsorptive techniques such as biliopancreatic diversion and duodenal switch, or a combination of both as in a Roux-en-Y gastric bypass (RYGB), one of the most common surgical procedures performed over the last years
BS is considered an efficacious technique with benefits concerning the treatment of comorbidities of the morbidly obese patients, it may bring long-term complications such as nutritional deficiencies, biliary lithiasis, disturbances in bone and mineral metabolism and an increased risk of nephrolithiasis [3,4]
A low-oxalate diet is recommended to prevent hyperoxaluria and stone formation after BS, the lack of information about oxalate content in foods can be an obstacle while trying to restrict oxalate from the diet
Summary
Obesity is one of the most important worldwide public health challenges predisposing to severe comorbidities such as diabetes mellitus, cardiovascular disease, cancer, sleep apnea and hypertension [1]. BS is considered an efficacious technique with benefits concerning the treatment of comorbidities of the morbidly obese patients, it may bring long-term complications such as nutritional deficiencies, biliary lithiasis, disturbances in bone and mineral metabolism and an increased risk of nephrolithiasis [3,4]. Such a risk is estimated to be around 7.6% in bariatric patients until 5 years after surgery, which represents almost a two-fold increase in risk if compared with morbidly obese patients [5,6], showing the greatest risk in malabsorptive procedures, intermediate risk in standard.
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