The Hard Truth About Kidney Stones: Part 2 - Resolving Kidney Stones
Now that we have evaluated how stones are formed, let’s take a look at how we can support the kidney as you work to resolve the kidney stones.
Citrate: One of the Body's Natural Stone Inhibitors
Citrate is one of our most important defenses against calcium stone formation. Citrate binds calcium in the urine, decreasing the amount of free calcium available to combine with oxalate or phosphate. It can also interfere with crystal growth and aggregation. Low urinary citrate (hypocitraturia) removes an important protective mechanism.
Why might citrate be low?
Acid-base balance matters. Normal urinary pH ranges, but is slightly acidic at around 6.0. When renal acid excretion creates urine lower than pH 5.5, citrate is depleted. In fact acidic urine is the dominant driver of stone uric acid, calcium oxalate, and cystine stone formations.
Other ways citrate is depleted in the urine is high dietary acid load (often created by inflammatory foods), certain renal disorders, chronic diarrhea, and hypokalemia (low potassium). Medications such as carbonic anhydrase inhibitors, PPIs, thiazides, loop diuretics, ACE inhibitors, glucocorticoids and exogenous testosterone also reduce urinary citrate. This is why citrate deserves attention on a 24-hour urine analysis rather than looking exclusively at calcium and oxalate.
How can we increase urinary citrate?
Citrus fruits, particularly lemon and lime, provide citrate, while potassium citrate is commonly used therapeutically in appropriate stone formers. One of the best ways to get citrate is to juice 1-2 lemons or limes in 8 ounces of water. Not only is it a great source of citrate, when mixed with water it is a great hydration source for the kidney.
What About Probiotics?
Certain intestinal bacteria are capable of metabolizing oxalate. Oxalobacter formigenes is probably the best-known example, while Lactobacillus and Bifidobacterium species have also been investigated for their potential effects on oxalate metabolism.
The intestinal microbiome may eventually prove to be an important part of understanding oxalate metabolism. Right now, we seem to know more about flying to Mars than the microbiome of the kidney. Hopefully we continue to develop strong probiotic support for the kidney system.
Can Herbs “Break” Kidney Stones?
A number of plants have traditionally been described as lithotriptic, sometimes translated as “stone-breaking.” Phyllanthus niruri or chanka piedra is probably the best-known example and has been studied for possible effects on calcium oxalate crystallization, aggregation, urinary chemistry, and stone formation.
In a study published in PubMed in 2018, researchers prospectively studied 56 patients with kidney stones <10 mm who took chanka piedra as an infusion for 12 weeks. They found an average number of stones decreased from 3.2 to 2.0 stones per patient (p < 0.001). In patients who had hyperoxaluria, 24-hour urinary oxalate fell from 59.0 to 28.8 mg/day (p = 0.0002). The investigators concluded that P. niruri (chanka piedra) contributed to the elimination of urinary calculi.
But, here is what I want you to remember, an obstructing stone is a serious condition, not an herbal-treatment experiment you can do on your own with AI. Severe or persistent pain, fever, chills, vomiting, reduced urine output, or suspected obstruction warrants prompt medical evaluation.
Treat the Physiology, Not Just the Stone
A kidney stone is the end product of a process. By the time calcium oxalate becomes a visible stone, it has been influenced by hydration, dietary calcium and oxalate, intestinal absorption, gastrointestinal function, liver metabolism, acid-base balance, urinary citrate, genetics, and the microbiome.
That is why recurrent stone evaluation should go beyond simply analyzing the stone itself. A comprehensive evaluation may include stone composition when available, serum chemistries and kidney function, calcium and PTH when appropriate, and a 24-hour urine analysis measuring urine volume, calcium, oxalate, citrate, sodium, uric acid, pH, and other relevant markers.
The pattern matters. As naturopathic doctors, we are trained to recognize patterns. High calcium with normal oxalate tells a different story than high oxalate with low citrate. High calcium accompanied by osteoporosis raises different questions than isolated dietary hyperoxaluria. Abnormal urinary pH changes the chemistry further.
There isn't one-for-all calcium oxalate stone protocol because there isn't one pathway to calcium oxalate stone formation.
From the dinner plate, to the gastrointestinal tract, to liver, bones, and to the kidney, we have traveled through a remarkable number of systems capable of influencing whether a microscopic crystal remains harmless or becomes a kidney stone. That complexity can be frustrating. I am always here to help.