In my video Alkaline Diets, Animal Protein, and Calcium Loss I presented evidence challenging the notion that our body is buffering the acid formed from our diet with calcium from our bones. How then is our body neutralizing the acid? Maybe with our muscles! Our blood gets more acidic as we age and our kidney function declines, and this may be a reason we lose muscle mass as we get older. As a pair of researchers note: "The modern Western diet based on animal products generates an acid load that may cause a lifespan state of unnoticed and growing metabolic acidosis." This chronic low-level diet-dependent metabolic acidosis might contribute to the progressive shrinking of our muscle mass as we age.
Muscle wasting appears to be an adaptive response to acidosis. When our muscles break down, amino acids are released into the bloodstream. Our liver can then take these amino acids and make something called glutamine, which our kidneys can use to get rid of excess acid. And indeed, in a three year study I profile in my video, Testing Your Diet with Pee and Purple Cabbage, those over age 65 eating alkaline diets were better able to preserve their muscle mass, which the researchers think may be because the alkaline-producing fruits and vegetables helped relieve the mild acidosis that occurs with the ingestion of the standard American diet.
So what should we think about the latest review's question, "Does an alkaline diet benefit health?" If the question is "Does a diet low in meat, eggs, and dairy--all acid-producing--and high in fruits and vegetables with lots of dark green leafies benefit health?" then of course the answer is yes, an alkaline diet benefits health. But if the question is "Does it matter what our 'peeH' is (whether our urine is acid or alkaline) regardless of what actually goes into our mouth?" then the answer is... still yes, but the accepted benefits of having alkaline urine appear limited to two areas: lower risk of kidney stones and better uric acid clearance.
We've known about kidney stones and alkalinity for a while, but the uric acid data is new. Researchers have found that alkalization of the urine is effective for removing uric acid from the body. If you remember from my video Flesh and Fructose, uric acid is bad stuff (potentially increasing one's risk of fatal stroke, heart disease, and death), so clearing more from your system is a good thing.
Those eating plant-based diets appear then to have an advantage in this regard. The average vegetarian diet is alkaline producing, and the average meat-eating diet is acid producing. Even though there are some acid-forming meat-substitutes, like some of the Quorn products, they're not as bad as something like tuna, and they're typically consumed in smaller quantities than meat consumers consume meat. Since the protein in plants is usually accompanied by much more potassium (which is alkalinizing), there is good reason to try to meet protein needs from plant sources. And when researchers actually measure urine pH, those eating strictly plant-based diets have the greatest advantage, with significantly more alkaline urine than omnivores.
How can we tell what our urine pH is? Well we can be all boring and order some pH paper strips to pee on. Or... we can use what everyone should have right now in their crisper, a purple cabbage. Everyone should have a red or purple cabbage in their fridge since it is not only one of the single best nutrition bangs for our buck, but we can also do science with it!
First, either boil some purple cabbage until the water turns deep purple or (a quicker and safer way since there's no hot liquids) blend some raw with water in a blender and strain out the solids. Then what you can do with that royal purple liquid is pour it in the toilet bowl after you urinate. (You can imagine how much fun kids have with this!)
If it stays purple, your urine is acidic and you should eat more dark green leafy vegetables. If the toilet bowl turns pink, your urine is really acidic, so you should definitely eat more dark green leafy vegetables. We're looking for blue. If it turns blue that means your urine is neutral or even basic. If it's sky blue, you should... continue to eat more dark green leafy vegetables. Now I have a low-flow toilet, so there's very little water in the bowel to start with. The effect might not be as dramatic if diluted in a larger quantity of water. For a step-by-step tutorial, see my video Testing Your Diet with Pee & Purple Cabbage.
Cherries may also help lower uric acid levels: Gout Treatment with a Cherry on Top.
Why do I always go on and on about dark green leafy vegetables? Check out my 58 videos on greens and find out! : )
-Michael Greger, M.D.
Image Credit: your neighborhood librarian / Flickr