Most people believe that tomatoes are linked with kidney stones. But are tomato seeds really to be blamed? We asked Dr Hemal Shah, Senior Nephrologist, Secretary, Amar Gandhi Foundation, Mumbai whether tomatoes are harmful for the kidneys. Here is what he has to say.
Do tomatoes cause kidney stones?
No. It is myth that tomatoes cause kidney stones. Tomatoes are one of the most commonly eaten vegetable in the world and if it was responsible, then the number of people suffering from kidney stones would be alarming.
Then how did this myth arise?
Tomatoes contain oxalates, which are responsible for the formation of kidney stones. However, what people fail to understand is this quantity of oxalates in tomatoes is not enough to cause kidney stones because 100g of tomatoes contain only around 5mg of oxalates. Also people diagnosed with kidney stones are advised to limit and not completely shun tomatoes from their diet.
Can changing the diet prevent kidney stones?
Not all kidney stones are made up from the same crystals. It can be formed due to calcium oxalate or other oxalate crystals, uric acid, struvite stones and cystine stones. However, oxalate crystals are the most common types of kidney stones.
Just as eliminating tomatoes from your diet will not help, it is a common misconception that that some foods such as meat increase the risk of kidney stones.
For example, if it is caused due to excess uric acid in the body, then medications will be recommended. Foods that are rich in purine content such as animal proteins from fish and meat are restricted. However, in this case, diet does not play a major role and hence, cutting down on these foods might fail to improve the condition unless supported by medications.
Also, if you suffer from oxalosis, an inborn error of metabolism, where kidneys fail to eliminate calcium oxalate crystals from the body and thus, these gets accumulated in the body leading to stone formation then diet modification will not suffice.
Although a diet low in oxalates will be prescribed to patient suffering from this condition, medications form the major line of treatment.
So what causes kidney stones?
An underlying health problem, deficiency of certain enzymes or metabolic problems can put you at risk of kidney stones. You might need medications to treat these underlying condition.
Tips to prevent kidney stones
-In India, the number one cause of kidney stones is poor hydration. This could be due to weather or availability of pure drinking water. Hence, whether you have a desk job or field work, ensure you drink at least 2-3 litres of water/fluids every day.
-Most people tend to drink a litre of water in the morning and a litre at night, which is not good for the kidneys. Instead, you need to religiously drink fluids throughout the day to dilute the urine and thus, prevent kidney stones in the long run.
-If the kidneys are not functioning properly or if you suffer from diabetes and hypertension, then a diet low in proteins is advised, which means restricting non-vegetarian food, dal, milk and milk products is advised.