I’m learning that some of my friends have suffered the ravages of kidney stones. That made me curious.  Why and how would the body even make such a by-product?  I had to dig into this. I’m sharing what I learned…

What are “stones” and why do we make them?

You’ll know you have one if it is large enough to be felt when you urinate, at least those that are about the size of a tiny seed, (approaching about 0.5 mm. or larger in diameter). Likely those and even slightly larger ones will pass without any, or very little, pain, just enough of a sensation to provoke your curiosity. Even if there is no pain, if you do notice that you are experiencing some kidney stones, you’d be wise to discuss the matter with your doctor before they grow larger and especially before they become so large that they may get stuck. The larger ones can really mess up your day. Early detection and early identification by your doctor of stone type may help you to make some very slight adjustments to your choice of foods and beverages in such a way as to completely avert a future episode and crisis.

The larger-sized stones are often passed with a noticeable amount of discomfort and even blood in the urine. Danger arises if they don’t pass. You may need heavy-duty pain medications or surgical intervention including, but not limited to, blasting them into tiny pieces using microwaves or lasers.

How and why are they formed?

These are the most common types of kidney stones (See End Note 1):

  • calcium oxalate – high calcium excretion and/or high oxalate excretion.
  • calcium phosphate – high pH urine resulting from high calcium in urine and alkaline urine.
  • uric acid – caused by urine that is acidic for long periods of time, from consistently eating too much animal protein, I.E., meat, fish, and shellfish.
  • Struvite – caused by infections in the kidneys.
  • Cystine – caused by cystine escaping the kidneys into the bladder to form crystals.

According to Dr. John McDougall,(See end Note 2), up to 5% of the population may be affected by kidney stones. Of those who are, more than 80% of the time, those stones are of the calcium type mentioned above, with men experiencing the greater incidence of stone formation.

Dr. McDougall goes on to mention a study showing that high dietary protein is the likely cause that separates the high incidence in industrialized countries from the much lower incidence in underdeveloped countries. [The likely rationale being that industrialized countries can afford to buy and consume animal proteins more often and in larger quantities than can the much poorer nations.] Dr. McDougall explains that high protein intake causes the body to excrete calcium from the bones as well as increasing other substances that make their way into the urine, presenting higher than normal levels of calcium in the urine where it can then form stones.

Generally speaking, too much calcium, oxalic acid, and/or uric acid in one’s urine can cause stones. The highest acid loads are provided by red meat, poultry, fish, and eggs. Some cheeses and grains provide acid. Phosphoric acid from colas is another source.” (See end Notes 1 and 2)

The body is designed to keep the blood within a very precise acid-alkaline range. When acid levels in the blood get too high, then, as Dr McDougall reminds us, “…The bones dissolve…to neutralize the acid…” (See end Note 2)

The following advice also comes to us from the National Institute of Health website (See Note 1):

Body weight, genetics, food types and fluid intake may be noteworthy factors involved in affecting stone formation. It also suggests that, if you are susceptible to stone formation, drastically reduce, or avoid these potential, stone-forming foods:

  • Beets, chocolate, spinach, rhubarb, tea, and most nuts are rich in oxalate.
  • Colas are rich in phosphate.

Recommendations based on the specific type of kidney stone include the following:

  • Calcium Oxalate Stones:  reduce sodium,  animal protein,  such as meat, eggs, and fish, get enough calcium from food or taking calcium supplements with food, avoid foods high in oxalate: spinach, rhubarb, nuts, and wheat bran.  [“Vegans with stones” take note.]
  • Calcium Phosphate Stones:  reduce sodium,  animal protein,  get enough calcium from food or taking calcium supplements with food.
  • Uric Acid Stones:   limit  animal protein.

SODIUM (salt from your shaker or extensively used in the packaging industry for canned and convenient foods) causes the kidneys to excrete calcium into the urine.

People who have had kidney stones should drink enough water and other fluids. Some studies suggest citrus drinks like lemonade and orange juice, because they contain citrate, helps by preventing crystals from growing into stones.


  1. “Diet for Kidney Stone Prevention” by National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/health-topics/urologic-disease/diet-for-kidney-stone-prevention/Pages/facts.aspx
  2. “Protein Causes Kidney stones” by Dr. McDougall. The MCDOUGALL NEWSLETTER. April-May 1999. https://www.drmcdougall.com/newsletter/apr_may.99.2.html