If you’ve never had kidney stones, keep doing what you’re doing. If you have, here’s some interesting info.
Basically, as long as you are hydrated, your kidneys are usually able to cope with everything you do and drink. But large crystallized compounds called kidney stones can form under the following conditions:
1: Not enough calcium in your diet, or coming into the kidneys, to bind to the little oxalates and push them along. So potentially you have a big gang of lonely oxalates hanging out temporarily in your kidneys. If you pee them out, you’re okay. But if you don’t, they get together and form crystals as soon as other stuff shows up.
2. Too much calcium without enough water, which turns into calcium crystals in the kidneys, that don’t get out if they get too big. (And then when oxalates come along, they bind to these crystals, and suddenly you have a really big kidney stone.) Calcium oxalate crystals being formed in your digestive system is normal, but having them form in your kidneys is the most common kind of kidney stone.
3. Too much cystine in your kidneys, period. Cystine, an essential amino acid, usually isn’t a problem unless you have cystinuria, a fairly rare genetic disease that messes with absorption.
4. Too much calcium phosphate in your kidneys without enough liquid. Those lonely calcium crystals can also get together with phosphates and make calcium phosphate crystals, or even join calcium phosphate with existing calcium oxalate crystals. This means you have a lot of calcium and not enough oxalates in your tummy… and something else going on. Urinary tract infections, but also other kidney problems or hyperthyroidism.
5. Uric acid crystals that actually turn into stones. Bad, bad dehydration is what causes this, or really acidic urine, or certain diseases. They can actually treat it short term with baking soda/bicarbonate of soda antacid!
6. Struvite stones = magnesium ammonium phosphate. Caused by really alkaline urine, which doesn’t usually happen unless you have an infection somewhere. They give people stuff to neutralize the pH and deal with the stuff in the stones.
If this isn’t a good recap of what I’ve read, read up on it for yourself.
So basically, it benefits you to eat/drink lots of calcium, so that the oxalates bind to it in your tummy instead of in your kidneys.
And you should drink a fair amount of water every day, so that all the various kinds of crystals do not form in your kidneys, and don’t get to the point that they are big masses that don’t dissolve easily.
And you should urinate and clear things out, because otherwise your kidneys will just work hard to concentrate everything into uric acid crystals, while all the other crystals have more time to get together and cause trouble.
If people know they tend to get specific kinds of kidney stones, their doctors will have specific recommendations. (There seem to be a lot of ins and outs, often based on what you are already taking in vitamins, prescription drugs, etc. Excess Vitamin C can turn into oxalates, and Vitamin D pills often include extra calcium.)
But what else helps?
The juice of citrus fruit and melons contain citrates, which can also bind to calcium in your kidneys and help you pee it out, and thus keep oxalates moving on out of the kidneys instead of making stones. This is one reason why lots of multivitamins and electrolyte drinks contain potassium citrate.
Nuts, potatoes, chocolate, black tea, beets, rhubarb, bran flakes, currants, leeks, summer squash, sweet potatoes, tomato soup, grits, tofu, Concord grapes, and spinach are high in oxalates. But they also tend to make you urinate, which usually is good for kidneys. So you have to think about levels. Eat/drink calcium with them, basically, and don’t pig out every day.
(In the UK, where people usually drink tea with milk or cream, they don’t have to worry about black tea oxalates as much. But remember, almond milk is also a nut.)
Or you could look up other tonics to encourage urination, that don’t include oxalates. (Just don’t use peppermint tea, as some people have good luck with it, but it seems to bring on kidney stones in others.) “Palo azul” or “azul tea” is a bark-based tea that is supposed to do wonders, but I don’t know anything about it. Green tea or oolong tea is a lot easier to find, and apparently fights stone formation. (They are both low in oxalates, because of how they are processed after picking.)
Eating too much meat or too many carbs and sugars, all at once, can stress out your kidneys. Don’t do that, or don’t do it for days and days in a row.
Don’t stress out. Some people’s kidneys don’t work well when they’re unhappy, angry, anxious, etc. (Probably stress hormones.)
Resveratrol fights kidney inflammation and helps your kidneys keep pushing junk out. It’s found in peanuts (a nut!), cocoa (chocolate!), grapes, blueberries, strawberries, mulberries, bilberries, and cranberries. In grapes, it’s only present in the skins, which is why red wine has resveratrol and white wine mostly does not. (The skins are strained out of white and rose wine at an earlier point in production.) But your body metabolizes resveratrol and doesn’t grab a lot of it, which is why there are pills.
Drink water and go to the bathroom regularly. Seriously. Then you don’t have to remember this stuff.