Don’t Get Stoned this Summer


Takeaway First

Kidney stones are on an upswing as the days get warmer. Quite a few of our patients are passing stones at our clinic in New York. There are many things you can do to prevent kidney stones, but above all: drink tons of water.

Kidney stone facts:

Kidney stones are most common in Caucasian men and least common among African-American females.

Calcium kidney stones are made of 80% calcium oxalate (CaOx).

It has been suggested that kidney stone risk increases in hot climates.

Frequent or intense exercise can cause an increase in kidney stone formation.

While only about 10% of men will develop kidney stones in their lifetime, that percentage goes up to 30% if there is a family history.

What exactly are kidney stones?

Kidney stones are exactly what they sound like. They are stones (little rocks, but sometimes not so little—ouch!) that form when minerals accumulate in your kidneys. Most of the time these stones pass through the system without causing much pain or discomfort. Other times, if the stone become bigger than 3 mm, they pass with excruciating pain.

I mean, EXCRUCTIATING PAIN. If you have ever passed a stone, you know what I’m talking about.

Women patients who have passed stones and delivered babies have said delivering babies is like a walk in a park compared to passing a kidney stone.

The pain often starts at the lower back (flank), and it radiates down to the groin. This pain is caused by pressure in a part of your body between your kidneys and bladder called the ureter, which itself is only 3-4 mm wide.

What increase your likelihood to make stones?

Other than genetic causes (where your body simply likes to make stones), there are two main causes: being overweight and dehydration.

So, yes, losing weight and drinking tons of water can really help.

What else can you do to stop making kidney stones?

Drink a ton of water. You should urinate 2 liters of urine every day.

Take 500 to 1000mg of magnesium citrate every day.

Take Vitamin B6—25 mg daily. A B6 deficiency increases urinary oxalate, which may lead to kidney stones.

When magnesium is used in conjunction with vitamin B6, it has an even greater effect.

Drink lemon juiceabout one-half cup of pure lemon juice (enough to make eight glasses of lemonade) every day. Lemon juice raises citrate levels in the urine which protects against calcium stones.

Drinks to avoid: orange and grape juice and soda. You do not need to avoid coffee and alcohol, but DO NOT need to be avoided, but remember that these cause dehydrationso drink, drink, drink (water, that is).

What to do if you are a kidney stone former (that you thought you shouldn’t do)

Forget about eating a low-oxalate diet. My patients who eat a lowoxalate diet become fat and increase their risk of heart disease and cancer. This approach is disastrous for overall health because many protective foods high in oxalates are vegetables, fruits and nuts – all things I highly recommend. In fact, recent research has demonstrated that a diet high in fruits and vegetables DECREASES the risk of kidney stones (Turney et al. 2014).

It has been suggested that people who form kidney stones should avoid vitamin C supplements, because vitamin C can convert into oxalate and increase urinary oxalate. Initially, these concerns were questioned because the vitamin C was converted to oxalate after urine had left the body. However, newer trials have shown that as little as 1 gram of vitamin C per day can increase urinary oxalate levels in some people, even those without a history of kidney stones.

In one case report, a young man who ingested 8 grams per day of vitamin C had a dramatic increase in urinary oxalate excretion, resulting in calcium-oxalate crystal formation and blood in the urine. On the other hand, in preliminary studies performed on large populations, high intake of vitamin C was associated with no change in the risk of forming a kidney stone in women, and with a reduced risk in men. This research suggests that routine restriction of vitamin C to prevent stone formation is unwarranted.

Bottom line on preventing kidney stones?

Drink 4 to 8 cups of lemonade made with a least a half a cup of freshsqueezed lemon.

Drink enough water, about 10 glasses a day, and aim to produce about two liters of urine.

Take magnesium citrate, potassium citrate and vitamin B6 supplements.

Avoid drinking grapefruit juice.

Eat plenty of ALL fruits and vegetables. If you get kidney stones frequently, then avoid only spinach and almonds which are very high in oxalates. But eat plenty of the others.


Gershoff S, Prien E. Effect of daily MgO and vitamin B6 administration to patients with recurring calcium oxalate kidney stones. Am J Clin Nutr 1967;20:393-399.

Will E, Bijvoet O. Primary oxalosis: clinical and biochemical response to high-dose pyridoxine therapy. Metabolism 1979;28:542-548.

Turney BW1, Appleby PN, Reynard JM, Noble JG, Key TJ, Allen NE.Diet and risk of kidney stones in the Oxford cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC). Eur J Epidemiol. 2014 May;29(5):363-9.


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