Debunking – and Validating – the Alkaline Diet

Gwyneth Paltrow does it. So do Jennifer Aniston, Victoria Beckham, and Jared Leto. Tom Brady does as well. The trend of eating foods with a high pH (more “basic”) and avoiding foods that are acidic is commonly known as the “Alkaline Diet.” Does it work? As usual, it’s complicated.

First of all, let’s have a quick review of terms like pH, acids, and bases. “pH” refers to “potential of hydrogen” in an aqueous (watery) substance. If that substance is 0-7, it is said to be acidic. If it’s exactly 7, it’s neutral. If it’s 7-14, it’s considered to be basic.

The major claim of this diet approach is that by eating foods with a high pH your body, particularly your blood, will avoid becoming too acidic. As a result, it will be easier to control weight and inflammation, as well as reduce the risk of serious health conditions such as osteoporosis, stroke, kidney stones, and cancer.

Sounds great, right? So, where’s the hang-up?

For starters, there’s no evidence that the pH of the food we eat has any effect on the pH of our blood. The pH of our blood is very tightly controlled by our body and is always slightly alkaline/basic (7.35-7.45). If it’s not in that range, it’s due to a medical condition and is a critical health issue. In other words, if the pH of our food changed the pH of our blood then a large serving of tomato sauce (which is acidic) might put each of us in the hospital.

The pH of our urine can vary, and can even be affected by what we eat; but since it’s excreted from the body, there’s no reason to think its pH has any impact on our health and what’s going on in the rest of our body.

What about our stomachs? They’re always acidic, very much so in fact. Typical pH of the stomach is 1.5-3.5. Even when you eat alkaline foods, your stomach stays acidic. Again, this is something our body needs to maintain so that the stomach’s acids can break down the food we eat to prepare nutrients for digestion.

So what does eating an alkaline diet actually do? It doesn’t change the pH of any body system of consequence. At the same time, many people do see health benefits. Why might that be?

Perhaps looking at the list of foods in the alkaline category will give us a clue. Most websites touting the benefits of an alkaline diet have a chart listing which foods fall into the alkaline and acidic categories. Which foods are alkaline? It’s almost all fresh fruits and vegetables!

So what this whole craze is really about is eating more fresh fruits and vegetables? Has anyone ever recommended that before?

Yes. Registered dietitians have been touting the benefits of these foods for a long time (including me). So have the Dietary Guidelines for Americans. So has the DASH diet. And many more.

My point is that this is not a novel concept; it’s just a new way to market it. It’s also deceptive, by suggesting that the real benefit of eating these foods is changing your body’s pH. The problem is, we don’t like to hear the same things we’ve always heard: “eat lots of veggies.” Instead, we like to have strict, dogmatic rules to follow to feel that we are in on some kind of nutritional secret. It’s more of a thrill that way. If you prefer that approach, that’s fine. Just know that those strict rules get old really quickly and that apples, berries, melons, nuts, seeds, and eggs, despite being acidic, are actually quite nutritious.