Vegan diets and kidney stones: What you should know

Veganism and Health

Australian star Liam Hemsworth declared he interrupted his vegan diet after suspecting that it may have been a factor for his kidney stones condition and hospitalisation. However, it is well known that the relation between diet and health conditions can hardly be generalised, as it depends on the eating habits of every individual. 

Miley Cyrus’ former boyfriend, best-known for his roles in The Hunger Games, The Last Song and The Expendables 2 said: ‘The first two years, I felt great. My body was strong, my cardio was high’. But suddenly, last year, he started ‘feeling lethargic’ and he was diagnosed with kidney stones. Knowing this condition is highly related to eating habits, he decided to change his diet, as he was told that otherwise, there would be a chance to get another one. Apparently, he thought that a plant-based diet did not work for him anymore, and he consequently had to ‘reassess it’. He also specified that his personal diet was particularly high in proteins and oxalates, one of the main causes of kidney stones. 

Veganism and Kidney Stones

Nevertheless, there are conflicting opinions about this topic. In a recent article published  by Harvard Medical School, it is possible to read that a diet based on animal products may lead to kidney stones, for ‘it boosts the level of uric acid’. More in general, it seems that an excessive intake of proteins can be triggering, as well as food containing a high amount of oxalate and phosphor: if combined with calcium, these substances can be a factor for the formation of stones. Beets, chocolate, spinach, rhubarb, tea, and most nuts are known to be particularly rich of these two substances. 

The doctors’ opinion

Doctor Susan Levin, Director of Nutrition Education for the Physicians Committee for Responsible Medicine, kindly agreed to explain the relation between kidney stones and diet, as well as the best ways to prevent this condition. 

First of all, can we say that there is a link between a vegan diet and kidney stones?

‘There’s nothing specific about a vegan diet and kidney stones. In fact, a plant-based diet may offer significant protection against stone formation. The risk factors include a family history of kidney stones, dehydration, Western-style diets, like high sodium, animal protein, and sugar, obesity, and certain medications or health conditions. We can say that most kidney stones are calcium oxalate stones. Oxalates appear to be problematic primarily in persons with low calcium intake. A vegetarian diet may offer significant protection against stone formation.’

Which are the best ways to prevent the formation of kidney stones?

‘To reduce the risks of kidney stones, the following evidence-based recommendations should be considered: 

• Drink plenty of water. Published guidelines suggest that daily water intake should be high enough to achieve at least 2.5 L of urine volume in order to prevent kidney stones.
• Reduce intake of animal protein and sodium. Diets high in animal protein are associated with increased risk of stone formation; conversely, protein restriction causes a reduction of urinary calcium oxalate and urate. It’s unclear if plant protein would lead to the same problem.
• Limit high-oxalate foods. American Urological Association guidelines recommend that clinicians counsel patients with calcium oxalate stones and relatively high urinary oxalate to limit intake of oxalate-rich foods and maintain normal calcium consumption.  However, a recent review of diets that are considered optimal for prevention of nephrolithiasis (i.e. kidney stones) concluded that the benefits of oxalate restriction are unproven, except for bariatric surgery patients.
• Get calcium from foods (versus supplements). Calcium intake from foods lowers the risk for calcium oxalate stones.
• Limit soft drinks. Sugar-sweetened drinks, including sodas and fruit punch, appear to increase the risk for kidney stones.
• Avoid of high-doses of vitamin C.’