Know Your Stones...Protect Your Kidneys
Author: Betty Kovacs, MS, RD
Medical Editor: William C. Shiel Jr., MD, FACP, FACR
Do you know your kidney stone?
The unfortunate thing about kidney stones is that once you have had one there
is a significant chance that you will have another one. Fortunately, there are
things that you can do that may help prevent future occurrences.
One of the keys to prevention is to learn about your previous kidney stones.
If you pass a stone and can save it, your doctor can have it analyzed to
determine precisely what kind of stone it was. Your doctor may order blood and
urine tests as well. The tests will be checking your urine volume and levels of
acidity, calcium, oxalate, sodium, citrate, creatinine, and uric acid. Knowing
what caused your stone will make preventing future stones more likely.
How can your diet increase the risk for calcium stones?
Approximately four out of five kidney stones are calcium stones. These stones
are often a combination of calcium and oxalate, but can also be a combination of
calcium and phosphate or a combination of all three. A great deal of research
has uncovered dietary factors that can lead to the development of these stones.
The beef about animal protein: Protein is an essential nutrient needed
for numerous functions in our body. The average American consumes about twice
the RDA for protein each day with the majority of it coming from animal sources.
Some research has shown a link between kidney stones and diets high in animal
protein, while others have found no difference in stone formation in animal
versus plant protein consumption. If the majority of your meals contain a source
of meat (for example, chicken, turkey, eggs, beef, seafood, pork, or dairy foods), then
the recommendation would be to cut back on the quantity and/or frequency that
these are consumed. Here are some ways to get protein from plant sources:
- Soy cheese
- Tofu
- Beans
- Chic peas
- Lentils
- Soy milk
- Whole grains
- Vegetables
- Nuts (if oxalates are not a problem)
Shake off the salt. Research is clear on the fact that the sodium
found in salt can cause problems by increasing the amount of calcium that you
excrete in your urine, which in turn increases your risk of another kidney stone
developing. The recommendation is to consume a maximum of 2,000 to 3,000 milligrams
(mg) of
sodium a day. The main source of sodium in our diets comes from processed and
prepared foods. The sodium is used as a preservative and taste enhancer in foods
such as canned foods, frozen foods, and cold cuts. Many of these products are
now available in low-sodium versions, so be sure to read the label. The food
label guidelines for sodium are as follows:
- Sodium-free: less than 5 mg per serving
- Very low sodium: 35
mg or less per serving or, if the serving is 30 grams (g) or less or 2
tablespoons or less, 35 mg or less per 50 g of the food
- Low-sodium: 140 mg or
less per serving or, if the serving is 30 g or less or 2 tablespoons or less,
140 mg or less per 50 g of the food
- Light in sodium: at least 50% less
sodium per serving than average reference amount for same food with no sodium
reduction
- Lightly salted: at least 50% less sodium per serving than
reference amount
- Reduced or less sodium: at least 25% less per serving
than reference food
The salt that you add while cooking or eating can easily put you over your
limit for the day. Each teaspoon of salt contains about 2,300 mg of sodium. Some
techniques for keeping your sodium intake down are:
- Prepare food yourself when possible
- Choose fresh or frozen vegetables
- Limit or avoid processed, cured or pickled foods
- Try sodium free seasonings
for flavor. Some great options are pepper, fresh garlic, garlic power, fresh
onion, onion powder, lemon juice and vinegar
- Replace high sodium sauces with
dry mustard, vinegar, or homemade low sodium sauces
- When eating out, ask for
the sauce on the side and add it sparingly
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