Guest article by Monica Reinagel, MS, LD/N aka “The Nutrition Diva” ™

Many people are convinced that balancing the pH of your diet will help keep you healthier. There are several popular diet books based on this idea and you can find lists of acid- and alkaline-forming foods on the Internet. Lots of you have written to ask whether this is something you need to pay attention to.

The Acid/Alkaline Theory of Health

The acid/alkaline theory of health and disease goes something like this: Every food you eat leaves a residue in the body after it is fully digested. That residue, or ash, is either acidic or alkaline. This has nothing to do with whether the food itself is acidic. Lemons, for example, are acidic, as you can tell by their pucker-factor. And yet lemons leave an alkaline residue.

To keep this from getting confusing, the preferred terminology is that a lemon is an acidic food, but not an acid-forming food. Some people believe that if we eat too many acid-forming foods our blood and/or tissues become acidic and that this promotes disease. They reason that eating more alkaline-forming foods will balance the pH in our bodies and restore health.

What are the Acid- and Alkaline-Forming Foods?

In general, fruits and vegetables are alkaline-forming, and meats and grains are acid-forming. But it gets way more complicated than that. You can find lists of acid- and alkaline-forming foods on the Internet–but I’m not entirely sure where these lists come from or how they are generated. I’ve never seen one that had any citation or source information attached to it. Furthermore, they tend to contradict one another–foods are listed as acid-forming on one website and alkaline-forming on another.

That’s one of things that makes me wonder about the validity of this theory. The other thing that I find notable is that in all the medical literature, I cannot find one study that’s ever tested this theory.

Researchers love to test theories. That’s what they do! And just about every diet theory that’s been proposed in the last thirty years has been the subject of some sort of published research. You can find studies on the effects of anti-inflammatory diets, low-carb diets, low-glycemic diets, high-protein diets, vegan diets, and Mediterranean diets. But apparently, no serious researchers have ever found the acid/alkaline theory plausible enough to look into.

Why not? After all, it’s absolutely true that maintaining the proper pH in your body is crucial–not just to staying healthy, but to staying alive at all. If your blood got even slightly too acidic or too alkaline and stayed that way for more than a few minutes, you’d be in a coma or worse. But what you eat actually has very little effect on the pH of your blood. Believe me, nature is not about to let your survival hinge on dietary discretion.We have several systems in place to maintain pH balance in our bodies, no matter what we eat.

Flushing the Evidence

If you’ve read anything about this theory, you might have come across the part where they tell you to test the pH of your urine. You can buy inexpensive pH sticks at the drug store and pee on them. If you try this, you’ll see that what you eat does change the pH of your urine. And to some, that is proof that the acid/alkaline theory is true. But actually, the reason that the pH of your urine is changing is so that the pH of your blood doesn’t. The kidneys are one of the major ways that your body maintains a constant pH.

Worrying about the pH of your urine makes about as much sense as worrying about the dirt in your trash. Both are leaving the premises. The trash is carried out to the curb and any dirt it contains isn’t going to make your house dirtier. Likewise, the urine is being flushed and isn’t making your body any more acidic.

Are There Consequences to Eating Too Many Acid-Forming Foods?

There’s a slightly more sophisticated version of this theory that acknowledges that a healthy body is able to maintain its pH no matter what you eat. However, if you eat too many acid-forming foods, the effort of maintaining pH will deplete the body’s energy or resources, leaving you vulnerable to disease. For example, another way that your body balances pH is to pull calcium from the bones. So, it follows that eating too many acid-forming foods might promote bone loss.

Again, I’ll just point out that the long-term consequences of a so-called acidic diet are purely theoretical. They have never been confirmed by any sort of direct research that links the acid/alkaline residue of the diet with health outcomes. But we certainly have plenty of indirect research. For example, the effects of high-protein diets, which are presumably high in acid-forming foods, have been studied.

In fact, you might recall a recent episode that I did on nutrition and bone health. I mentioned that high-protein diets can increase bone loss—but only in people who are calcium deficient. In other words, if you are getting enough calcium and other minerals in your diet, you’ll have more than enough to maintain your bone mass and buffer the effects of acid-forming foods.

Why You Might Want to Follow a pH Balanced Diet ANYWAY

For now, the acid/alkaline theory of disease is just that: a theory. Parts of the theory are plausible; some are a little silly. Most are untested. And, maybe one day, researchers will do some large-scale studies on the effects of dietary pH on health. When they do, I have a feeling they might discover that people who eat more alkaline foods are, in fact, healthier.

After all, what would that diet look like? It would be high in fruits and vegetables. And, unless this is the very first episode you’ve ever listened to, you can probably recite with me the many benefits of eating more fruits and vegetables.

A diet high in fruits and vegetables is going to be high in antioxidants, vitamins, minerals, and fiber. Plus, if you’re also trying to limit your intake of acid-producing foods– which are meats and grains–you’re probably going to end up cutting out a lot of foods that are also high in sugar, fat, calories, and sodium. Regardless of the pH aspect, that sounds to me like a good way to improve your health.

In other words, I don’t think anybody is going to get hurt following a pH-balanced diet, as long as the diet is otherwise balanced and nutritious. I just think that it’s an unnecessarily complicated way to get to the same old punch-line: Eat more vegetables, less junk, and nothing to excess.

About the Author: Monica Reinagel is a licensed nutritionist and author of Secrets for a Healthy Diet: What to Eat, What to Avoid, and What to Stop Worrying About. For more of Monica’s evidence-based nutrition advice, check out her weekly Nutrition Diva podcast. View the complete archive »