The Cap’n Kidney Crunch Diet: A Serious Solution to End-Stage Renal Failure?

“You got to be careful of fruit,” said the doctor who came to see Nicole in the ER. “I like to eat fruit. But it’s really high in potassium. Not good if you’re on dialysis.”

As I related in the last four blog posts, after waking up in a semi-paralyzed state (and nearly suffering heart failure), my wife had been rushed by ambulance to the big city hospital in London, Ontario. As her kidneys went kaput ten years ago, she relies on a dialysis machine to keep her alive. Sadly, that $30,000 machine, the size of a large bar fridge, doesn’t do as good a job as those 155 grams of kidney tissue her mother gave her for free. Especially since dialysis only happens three times a week. Kidneys work 24/7.

Prior to the ER drama, Nicole had eaten “too many” (if you don’t go pee) potassium-rich yams. The potassium overload interfered with the way her nerves conduct signals to her muscles, gut and heart. But the doctor assumed she’d been testing the 30 Bananas a Day diet, not merely baked yams with ginger for breakfast.

“Actually,” said Nicole. “I don’t eat any fruit.”

Nicole has a bit of an intolerance to fructose sugar in fruit. Gives her gas.

“Well,” said the doctor. “Healthy food tends to have a lot of potassium.”

I guess that’s what makes it healthy.

Nicole’s first nephrologist (kidney doctor) actually advised her to eat Cap’n Crunch. No wonder dialysis patients are so confused over what to have for breakfast. Organic yams, deadly! Processed cereal, life saver?

Wikipedia says: “Cap’n Crunch is a product line of corn and oat breakfast cereals introduced in 1963…” But if you look on the official  Cap’n Crunch website you’ll see that it actually contains more refined sugar than oat flour. Could someone please update Wikipedia to say:  “…a product line of corn, sugar and oat breakfast cereals introduced in 1963…”?

Of course, Captain Crunch does contain plenty of (added and synthetic) vitamins and minerals. They had to throw in some supplements so that the RDI of nutrients wasn’t 0% all the way down the list. Please note, however, that these so-called nutrients come after salt and “Yellow 5” food colouring on the ingredient list. That could either mean there’s an awful lot of salt and food colouring added or not many nutrients (even fake nutrients) after all.

Yellow 5, by tho way, has been linked to hyperactivity, asthma, migraines, thyroid cancer, anxiety, clinical depression, blurred vision and (this sounds neat) purple spots on the skin, according to But it wouldn’t hurt your kidneys, I’m sure.

To their credit, The Quaker Oats Company doesn’t brag about Cap’n Crunch’s vitamin content on their site. How could they? The cereal contains more of the preservative butylated hydroxytoluene (BHT) than it does of artificial vitamins B₉ and B₂. Tokyo Metropolitan Research Laboratory of Public Health published a study showing that BHT injected into rats caused “some damage” to the kidneys as well as the liver.

So how could a concoction of white sugar, oxidized flour and a renal-damaging chemical be the ideal breakfast for people so ill they require dialysis to stop from dying? Easy! One (2 cup) bowl of Cap’n Crunch contains less than 140mg of potassium. Compare that to an equal portion of baked potatoes which tops 2490mg.

Of course, even 2490mg doesn’t surpass the most conservative limit (I’ve seen) for dialysis patients of 3000mg per day. But it’s not easy living off a mere 500 calories of potatoes per day.

So what’s a dialysis patient to do? Die quickly eating a modicum of garbanzo beans and sweet potatoes? Or die slowly feasting on Cap’n Kidney Crunch (as the website boasts, it’s “an easy snack that goes great with couch time, anytime”)?

Fortunately, the conundrum isn’t so black-and-white. Up until our (dire) experiment with a higher-potassium diet, Nicole had been managing to keep her potassium level between 5-6mEq/L. Yes, a bit out of normal range, but it never seemed to cause any problems. We decided to just go back to that diet, less a few ingredients.

Back to that harrowing day at University Hospital… Upon receiving dialysis treatment in the ER, Nicole’s potassium levels returned to normal. And so did she. By 7pm we were ready for the 90 minute taxi ride home through heavy snowfall. Boy, we missed that ambulance ride which raced us there in 45-minutes, sound gun firing.

“Remember, stay away from the fruit,” the doctor said as we left.

Actually, blueberries were one of the first foods we added to Nicole’s diet the next day. Despite their reputation as a “nutritional powerhouse” blueberries are even lower than the good Captain when it comes to potassium. One cup (half-bowl) contains only 114mg.

Today, however, it seems the National Kidney Foundation omits Cap’n Crunch from their list of breakfast cereal recommendations for the “next time you want to get a healthy start to your day.” Oddly, still on their list are Fruit Loops, Frosted Mini-Wheats and, yes, even Trix (“Silly rabbit! Trix are for kids…kidney patients!).

In a future blog post I will show you what Nicole has been eating since the near-death-by-yams experience. Her potassium level has remained safely below 5mEq/L. And she’s able to maintain this normal potassium level eating whole, natural, vegan dishes, not processed, sugary cereals.

What About Nutrient Deficiencies? Many people are concerned that a low-potassium, vegan diet can lead to nutrient deficiencies. If whole foods are used, I don’t think this is likely (or even possible). See What’s Worse: Deficiency or Excess?

About the Author: John C. A. Manley researches and writes about alternative treatments for type-1 diabetes and its many complications. His wife, Nicole, of 15 years has had type-1 diabetes for four decades. Together they have lowered her HgbA1c below 5.5%, regained thyroid function, increased kidney function and reversed gastroparesis. Read more about their journey out of the T1D matrix or subscribe to their Diabetic Dharma blog..