Discussing the difference between acidic and acid-forming foods, explains how the body maintains pH balance, and evaluates the potential health benefits and misconceptions surrounding pH-balancing diets.
Discussing the difference between acidic and acid-forming foods, explains how the body maintains pH balance, and evaluates the potential health benefits and misconceptions surrounding pH-balancing diets.
Hello and welcome to the Nutrition Diva podcast. I’m your host, Monica Reinagel, and today I thought we’d take a closer look at claims that an alkaline diet will help keep you healthier. There are slew of diet books out there, claiming that balancing the pH of your diet will balance your body chemistry, prevent disease, heal your gut, help you lose weight, and generally optimize your health. You’ll also find extensive lists of alkaline and acid-forming foods, and even pH-strips to test the pH of your saliva and urine.
Let’s sort fact from fiction, starting with a few facts.
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.
In general, fruits and vegetables are alkaline-forming, whereas meats and grains are acid-forming. The devil, of course, is in the details. And if you go poking around online, you’re likely to run into a lot of contradictory advice: foods that are listed as acid-forming on one website listed as alkaline-forming on another.
Sometimes, this is because of confusion between the pH of the food itself and the pH of its ash. Or, it may be due to wellness influencers who don’t really understand the science and end up cutting and pasting bad information from some other influencer’s misinformed materials. (There’s a lot of that going around in the world of wellness influencers.)
Anyway, some people believe that if we eat too many acid-forming foods our blood and/or tissues become acidic and that this promotes disease. Therefore, we can balance the pH in our bodies and restore health by eating more alkaline-forming foods.
It’s absolutely true that maintaining the proper pH in your body’s tissues 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 your dietary discretion. We have several systems in place to maintain pH balance in our bodies, no matter what we eat.
The kidneys help by filtering out excess acids from the blood and excreting them in urine. 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.
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.
The lungs also help by regulating the amount of carbon dioxide (CO2) in the blood. When you exhale, your lungs expel CO2, which is acidic. By adjusting how fast and deep you breathe, your lungs can quickly increase or decrease the blood's acidity, keeping pH levels within a healthy range. Together, these systems ensure that the body’s pH remains balanced and stable.
There’s a slightly more sophisticated version of the acid-alkaline 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 resources, leaving you vulnerable to disease.
For example, another way that your body balances pH is to pull calcium from the bones–although because this works much more slowly than your lungs or kidneys, it’s definitely a secondary strategy. However, it’s plausible that over time, an acid-forming dietary pattern might promote bone loss. And several studies have attempted to test this hypothesis.
Cited: Acid Balance, Dietary Acid Load, and Bone Effects-A Controversial Subject - PubMed (nih.gov)
In 2018, researchers writing in the journal Nutrients reviewed the evidence on this question, examining the relationship between dietary acid load and bone health, particularly focusing on osteoporosis.
On the one hand, studies show that when blood pH is at the low end of that rather narrow "normal" range maintained by the kidneys and lungs, cells called osteoclasts (which dissolve bone) are activated and cells in charge of forming bone (osteoblasts) are inhibited. And, clinical human studies have shown that supplementing with an alkaline substance (essentially, an antacid) can improve calcium balance and reduce bone resorption markers in the short term.
(Ironically, chronic use of antacids can negatively impact bone health because they make your body is less able to absorb calcium.)
On the other hand, meta-analyses have found no significant long-term effects of dietary acid load on bone mineral density or fracture risk–the real world consequences that we’re concerned about. The truth is that other factors, such as age, genetics, exercise habits, and overall nutrient intakes probably have a much bigger influence on our bone health than the acid load of our diets.
With all of that said, however, there may still be good reasons to eat a pH-balancing diet. It just may have less to do with pH than people believe. After all, what would that diet look like? Well, 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. And, if if you’re also trying to limit your intake of acid-producing foods, you’re probably going to end up reducing your intake of sugar, refined grains, and processed meats. 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.
Finally, I don’t think there’s any need to spend money on fancy alkaline water. Not only is there little evidence to support its benefits, but good old mineral water can provide many of the same benefits.
And as for supplements that claim to alkalize the body: Although they might have a minor, transient impact on blood pH, nudging it toward the top end of the normal range, alkalizing supplements are likely to have a much more dramatic–and not necessarily beneficial--impact on the pH of the stomach. The stomach needs to be a very acidic environment in order to optimize digestion and absorption of nutrients, including those that support bone health.
If you have a question you'd like me to answer, you can email me at nutrition@quickanddirtytips.com You can also leave me a message at 443-961-6206
If you could use some help actually putting all of the healthy diet advice we talk about on this show into action in your daily life, you might enjoy my other podcast. It’s called the Change Academy, and we focus on the science of habits and behavior change. You can find it on all the major podcast platforms. Just search for Change Academy.
Nutrition Diva is a Quick and Dirty Tips podcast. Our team includes Brannan Goetschius, Nathan Semes, Davina Tomlin, Holly Hutchings, and Morgan Christianson.
That's all for this episode. Thanks for listening! I'll see you next week.