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Iced Tea, Kidney Stones & Summer Suffering

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Warning! August is the cruelest month when it comes to kidney stones.

If you have not had a kidney stone, congratulations. You do NOT want to experience the pain that accompanies passage of one of these suckers. Women have told us that passing a kidney stone is far more painful than giving birth. Strong men cry because of the pain. Do not assume you will escape unscathed. Kidney stones are amazingly common. It is estimated that 13% of men and 7% of women will develop a kidney stone sometime in their lifetime.

If you have already had a kidney stone, there is a strong chance that you could have another. One study suggested that the likelihood of experiencing another kidney stone within five years is almost 50%. Ouch! And it's not just pain and suffering. Kidney stone complications can lead to life-threatening infections and kidney damage.

So what is it about the summer and August in particular that makes you more vulnerable to kidney stones? Studies have shown that the hotter it gets the more likely people will be hospitalized because of kidney stones. Hospital admissions for kidney stone emergencies peak in August and Google searches of kidney stones also surge during the summer, peaking in August.

Guess where the kidney stone belt is? Right! The southern part of the U.S. and states where it is hot-hot hot like Arizona.

So what is it about the summer that makes people so vulnerable to kidney stones? Experts have blamed dehydration as risk factor number one and that could well be true. When your urine is concentrated (as when the volume of your pee is decreased and the color is strongly yellow) there is a greater chance you will make a stone. The most common advice to avoid kidney stones is to drink a LOT of water to keep urine dilute.

There may be another reason why kidney stones are more common in the summer, especially in the south. Consider iced tea. John Miller, MD, is an assistant professor of urology at Loyola University Chicago Stritch School of Medicine. He suggests that iced tea consumption could be associated with kidney stones because iced tea contains a substantial amount of oxalate, which turns out to be a common component of many stones. According to Dr. Miller, the more oxalate in the diet, the greater the risk of kidney stones, especially in susceptible individuals.

Now this is pure speculation, but where do people LOVE iced tea? Right again. The south! Now that's not to say that people don't love iced tea in New England or Oregon. But in the south, iced tea is to adults what mother's milk is to babies. We know folks who could easily drink 5 to 10 glasses of iced tea in a day and not think twice. Although this is still association and not causation, you will see that the map of the south where kidney stones are so common (the kidney belt) is where iced tea is the drink of choice.

Other foods high in oxalates include:

Dark chocolate
Figs (dried)
Soy (milk, burgers, tofu, yogurt, etc)
Sweet potatoes
Swiss chard
Wheat germ, wheat bran

So, what should you be drinking in August (and other months) to reduce your risk of getting a kidney stone (or having another one)? Think lemonade! Lemons are high in citrate, which grabs onto oxalates in the digestive tract and prevents their absorption into the blood stream so they are less likely to concentrate in the kidneys. In truth, there have been few well-controlled trials to prove that less oxalate equals fewer stones. But there are some data to suggest that lemonade is linked to less risk of kidney stone formation. Here are some links you may want to check out:


Here is some additional information about reducing kidney stone risk:

Q. I read a letter from someone who drank lemonade to prevent kidney stones. I've had kidney stones for six years. I've been through two lithotripsies and taken sodium bicarbonate for two years. One of the physician assistants told me a year ago to drink a shot glass of lemon juice right before bedtime. I've had two ultrasounds since then and no kidney stones show up. I just wish my urologist had told me this.

A. Kidney stones are extremely painful, so preventive measures are most welcome. Doctors sometimes prescribe potassium citrate to block the formation of kidney stones. Because lemon juice also contains citrate, doctors have considered lemonade therapy to prevent kidney stones (Journal of Urology, April 2007). This calls for one or two quarts of unsweetened or low-sugar lemonade per day.

Pure lemon juice before bedtime can be hard on tooth enamel. Be sure to rinse well!

Q. I have a friend who was told she probably got her kidney stones from taking vitamin C and calcium supplements. There isn't a daily vitamin supplement out there that doesn't contain one or the other, if not both. What's the story on this?

A. The story is complicated, because the studies have given contradictory results. Calcium supplements appear to increase the risk of kidney stones (American Journal of Clinical Nutrition, Jul. 2011).

Some people make more kidney-stone forming oxalate after large doses (2,000 mg) of vitamin C (Journal of Nutrition, Jul. 2005). The amount you would get from a multi-vitamin, however, is not likely to cause problems.

Q. I am lactose intolerant and have to take calcium supplements since I don't drink milk. I have heard that these can cause kidney stones. Someone told me I should take Tums with calcium instead of calcium carbonate. Will this make a difference?

A. An article in the Annals of Internal Medicine (April 1, 1997, p. 497) showed that foods high in calcium help protect against kidney stones while calcium supplements increase the risk of stones by about 20 percent.

Regardless of the risk, taking your supplement with meals may protect you from any purported problem. You can also lower your likelihood of a kidney stone by making sure your diet is rich in potassium and magnesium from fruits and green leafy vegetables. Drink lots of liquids for added protection, but stay away from grapefruit juice which may boost the danger.

The active ingredient in Tums is calcium carbonate, which is also
found in many calcium supplements. We don't think there is a substantial difference. We would encourage you to keep your calcium intake from supplements below 800 mg per day to be on the safe side.


Menopausal hormone replacement therapy has come under a lot of scrutiny during the last ten years because of the Women's Health Initiative. This government-funded research was designed to determine the benefits and risks of HRT. It made headlines when the data showed an increased risk of cardiovascular problems among women taking hormones. There was also an increased risk of breast cancer.

Additional data collected during this study now show that women on estrogen are more susceptible to kidney stones. Those who continued taking HRT throughout the study increased their risk of stones by 39 percent. Women's average risk of kidney stones at this age is about 5 to 7 percent. With HRT that went up to 8.5 to 10 percent. The investigators urge women and their doctors to weigh this risk when making decisions about HRT use. 

[Archives of Internal Medicine, Oct. 11, 2010]

Bottom Line:

• Do not become dehydrated (Do not let your urine get too yellow)
• Keep iced tea consumption moderate, especially in the summer
• Avoid grapefruit juice (it too is linked to stone formation)
• Drink lemonade if you are at risk of developing a kidney stone
• When in doubt drink water!
• Keep calcium intake from supplements under 800 mg per day
• Increase calcium intake from vegetables and other foods
• Consider more magnesium from green leafy veggies or from a supplement
• Consider probiotics periodically

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I find myself really confused about when and how to take supplements with drugs or other supplements. I take hydrochlorothiazide 12mg for blood pressure. I take a probiotic and also a couple of Citrucel tablets for fibre. Looks like it is not a good idea to take the diuretic with the fibre. Anyone have any suggestions on where to find info besides the manufacturer? They just tell you when and how to take their own and not the combination.
Thank you,

Do you think water high in calcium could be a factor? We are temporarily living in the Gard region of France (Centre Quaker de Congenies) where the water has high levels of calcium, so much so that we have to regularly decalcify our appliances using vinegar. Would vinegar be as helpful as lemonade?

Thanks for your wonderful unique service.

My doctor and others have recommended citric acid for preventing reoccurring kidney stones. A bit of it dissolved in a glass of water. Have you heard of this? I have had 3 or 4 stones including one which had to be removed surgically.

Oops--I just inadvertently voted a one star for this article when what I intended was five starts! Is there any way this error can be corrected? I found this article to be very, very helpful & am sorry that my mistake may skew the results.


Susan, so glad you appreciated the article. No worries about the vote. It happens all the time and probably skews the votes down on everything. That said, others will likely help undo the error a bit by voting a bit higher.

Thanks for taking time to vote.

People often start dissolving their stones during the day, but build them up again at night! It is important to drink water at night, after you got up to pee.

Good grief! All the foods listed above (beets, blueberries, dark chocolate, cocoa, figs (dried), nuts, rhubarb, soy (milk, burgers, tofu, yogurt, etc.), spinach, sweet potatoes, strawberries, Swiss chard, wheat germ, wheat bran) look like really healthy choices for antioxidants and fiber. Would your recommendation be to keep eating all of them in moderation and add lemon juice to your diet? Is lemon juice effective if cooked? Only partially kidding when thinking that lemon pie would be a great prescription for better health!

Do colas increase the risk?



Also consider southerners tend to prefer Sweet Tea, whereas northerners drink unsweetened tea.

I have also seen recommendations to take no more
than 500 mg of calcium at a time.

This is interesting and good to be aware of for sure. I question substituting lemonade, however, because of all the sugar in it, or unhealthy sugar substitutes. Of course, "sweet tea" drinkers already have the sugar in there.

Also, it makes me a little nervous to see a list of healthy vegetables listed as potentially problematic. I would hate to think that people would decide they should avoid all of those vegetables that have so much nutritional value.

Never mind the kidney stones. I just love your updated personal photo!

Does it help to put lots of lemon in your iced tea?


Can't hurt...but not sure it will completely solve the problem.

I have had about 20 kidney stones starting when I was a sophomore in college.

Finally, my urologist asked me if I wanted to stop having them, and I said yes!!!

He put me on a low dose (12 mg) of HCTZ (if you take a higher dose, you also have to take a potassium supplement).

I have not had a kidney stone since I started taking HCTZ.

I find it distressing that all of my "healthy" staples are kidney-stone producers. The only item I don't ever touch is iced tea.

Just for what it is worth, I had several kidney stone episodes starting about 25 years ago and ending about 15 years ago. I live in hot Texas. I am 74 now. I suspect that getting older seems to stop kidney stones. I do not drink much water, but do drink carbonated drinks quite a bit. Maybe the carbonation helps prevent the stones. Kind of seems like the reverse of good health, right?

What bothers me about your list of high oxalate food is that most if not all of them are foods recommended for a healthy diet.

Two questions and comments:
1)_ you say that "Kidney stones are amazingly common. It is estimated that 13% of men and 7% of women will develop a kidney stone sometime in their lifetime." Ah, 7% is common? What number would you use to describe 'uncommon'? One Percent or less?

2)_ You also say "Consider probiotics periodically." My question is why would you only consider them 'periodically'? Aren't our guts constantly cycling though all the various flora and fauna until it finds a population that's a happy camper and that one starts to take over, so it's our job to keep a more complete healthy population and then keep them up - along with the use of PREbiotics? I'm confused here.

SEVEN PERCENT is not a low probability?? (and of course 1/10, 000 is not low if you happen to be the "1"). And probiotics should only be *considered* 'periodically'(???) when you had an entire show dedicated to how good they are and how Americans should learn to eat more fermented food AND if I recall even 'seed' with PREbiotics. Now I'm REALLY confused!! Is there a way that you can rephrase some of what you said, or are PRObiotics only to be taken periodically because some other research has shows them to be - what's the word? -- NOT GOOD(?)-- if taken daily? And no Prebiotic? I'm very confused!!! My partner is going to have her heart broken as she loves beets in any way-shape-or-form civilization has ever fond to eat them!!

I do not believe that about the tea. I have been a tea drinker since my teens. I drink it all year long, and all day long, not just summertime. I drank it with sugar until my 20s, but I've been drinking it unsweetened for the last 50 years. I will never give up tea, coffee, or the wonderful vegetables that are on your list. I refuse to worry or be one of the worried well.


Congratulations! You have never had a kidney stone and hopefully you never will. We love the foods on the list too, especially beets, dark chocolate and spinach. We will continue to eat them.

But...if you ever do get a kidney stone (and we sincerely hope you don't) you will do almost anything to avoid another. The pain truly is excruciating. Reducing the amount of oxalates in your diet would be prudent in such a situation and drinking lots of water (and some lemonade) might be a wise choice.

Very helptul information! I would also add that a 2:1 ratio of calcium to magnesium will help prevent all kinds of calcium-related problems. Low body stores of magnesium increase the risk of abnormal heart rhythms, which may increase the risk of complications after a heart attack. The proper amount of magnesium is critical.

My husband and one son both have had kidneystones that required surgery (as recently as last Fall 2011.) Would limeade or lime juice work as effectively as lemons? What are the differences in the properties of the two fruits limes and lemons? Thanks so much for the article.

Thank you for this most helpful information. I have had kidney stones for a long time. My urologist keeps an eye on them. One is 80% passible, so I will follow this advice so they don't get any bigger. I also have osteoporosis and Crohn's disease. I drink 2 cups of soy milk daily because of the calcium, which is good for my bones. I hope this amount will not hurt me in terms of kidney stone formation. My osteoporosis doctor says the soy is ok, but she may not know the dangers that soy presents.

Does this include green tea? I drink a lot of green and white tea over ice but no black tea. I also eat most of the vegetables listed and dark chocolate everyday.

This comment is so far down the list that I doubt anyone will read it, but anyway I drink lots of tea every day and no stones. I put in pure lemon juice from my tree so my suggestion is to add lemon juice in your tea. Maybe that will prevent the oxalate from developing a stone.

Why just iced tea, how about hot tea?

How about Arnold Palmers (1/2 tea & 1/2 lemonade)? Seems ideal. We drink it all the time. Had a stone about 32 years ago.

In the 1990s I had 2 surgeries to remove kidney stones. My urologist said my urine was not acidic enough. Since then I do two things to help, I regularly drink two things (not at the same time) cranberry juice and REAL lemonade made from concentrate, not lemon flavored drink. An Arnold Palmer is a good way to use both tea and lemonade. Knock on wood, I have not had to have anymore surgeries.

Wow. Thanks for the ice tea warning. Last year I wound up in the ER with severe lower abdominal/back pain. Thought it was appendicities, but turned out to be kidney stones. Very painful. Don't EVER want to experience that pain again.

Lemon pie, made with stevia instead of sugar, might be very healthy!
Live a little!

Interesting article. One study does NOT prove the conclusion you come to. 7% Male and 13% Female of population are NOT what I would consider "amazingly common" numbers. I do feel for those who have had kidney stones. It would be interesting to know if there is also a similar percentage of population suffering from kidney stones in countries that imbibe hot tea (GB, Ireland, most of Asia).

What is HCTZ?

Does the same concern apply to hot tea? Black tea vs. green tea?
I read recently that green tea can actually reduce the chance of developing kidney stones.

I am what's known in our family as a "tea Jenny", meaning I drink lots and lots of it - hot tea, that is. My nephrologist said I should stay away from all teas. However, when I asked him about Roiboos (South African redbush tea), he had never heard of it. He looked it up on the internet while I was in his office and discovered it is oxalate-free and also caffeine-free. So, it is my tea of choice now.

I too love all the things on the foods-to-avoid list. I eat them anyway and drinks LOTS of water. I keep a water glass by my bed and drink the whole glass when I get up for my middle-of-the-night trip to the "loo". If I get up a second time, I drink a second glass. I haven't had another kidney stone since increasing my water intake. (I drink about 6-8 glasses of water a day, more when i work up a sweat.)

For those who have never had a kidney stone, let me try to explain the pain. I have never given birth so I can't make that comparison. However, I have heard of animals caught in leg-hold traps who have chewed off a leg rather than die in the trap. If I could have eliminated the pain of passing a kidney stone by gnawing off a limb, I would have tried to!!!!

I have been having kidney stones since I was about 7 or 8 years old. I had them about every 2 to 3 years. Finally, about 5 years ago, my urologist told me I could talk a pill the rest of my life or I could avoid oxalates. As I did not want to take a medication I chose to reduce my oxalate intake.

I avoid all dark sodas, tea, spinach, etc. and am just experiencing my first stone in five years. I had never heard about the lemonade/juice solution before so I think I will incorporate that into my regiment. As I have been told I will probably always have them if a dietary change lengthens the time between occurrences.... I'm on board.

I am interested in some insight with regards to green tea or alternative teas.

I am female, always watched my diet, exercised and drank lots of water, never soda. When the menopause hot flashes became strong I wanted something besides water. According to available research flavored seltzer seemed to be the answer and I drank tons of it. After about 8 months, a kidney stone hit out of nowhere. The emergency room nurses and doctors told me it was the C02. Haven't touched it since.

I have had a stone that needed to be removed, and while I don't ever want to have another one, eliminating all of these good foods might lead to other painful and harmful effects. Maybe moderation is the key. I take calcium citrate. Does that solve the problem of getting calcium while also consuming citrate which helps prevent stones? Also, what about the recent research coming out of Asia that says that green tea might actually prevent stones?

I have had a stone that needed to be removed, and while I don't ever want to have another one, eliminating all of these good foods might lead to other painful and harmful effects. Maybe moderation is the key. I take calcium citrate. Does that solve the problem of getting calcium while also consuming citrate which helps prevent stones? Also, what about the recent research coming out of Asia that says that green tea might actually prevent stones?

HCTZ is Hydrochlorothizide. My MD prescribes it as a mild diuretic for moderate high blood pressure.

I have been having stones for the past 37 years; first one when I was pregnant (not unusual for women who are prone to stones, I'm told). This is the first time I've seen a possible explanation for the timing of my stones. I'm always on the alert from July - Sept. for stones, but never could figure the reason. I do live in the south and tend to drink more iced tea in summer.

I have had 2 Lithotripsies but rest of stones have been small enough to pass. One interesting fact about my stones is that as I've gotten older (60+yrs) the pain isn't as bad. Whereas in my younger days I had what doctors call "kidney colic," extreme pain when stone leaves kidney and travels down the ureter, now I no longer have this type of pain. It is only painful when the stone is moving around in the kidney. Now once it leaves the kidney I have a slight pinching sensation as it travels down the ureter. I guess my point is.... hang in there, stone sufferers, as you get older it may get less painful. I do try to follow a low oxalate diet (obtained on-line) and also take magnesium supplements (per doctor orders). Thanks Peoples Pharmacy for shedding light on the late summer timing of most of my stones!

Melanie-What kind of magnesium-there are so many to choose from. And what dosage? I've taken magnesium glycinate 400 mg but not sure if this also works.

Hi, I just had a large kidney stone broken up and I mentioned to the doctor I have begun taking magnesium citrate and he said not only is it more easily absorbed, but the citrate would of course be beneficial! My understanding is that the glycinate kind is not as easily absorbed and may be harder to digest. Good luck!

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