What Does ‘Alkaline’ Really Mean?

The word ‘alkaline’ is all over Instagram and health food labels—but as trendy as it is (and cool as it sounds), do you know what it actually means?

Let’s take a trip back to high school chem class. Remember the pH scale? In case you forgot, it’s a way of measuring how acidic or basic (a.k.a. alkaline) something is. Lemon juice, for example? Pretty darn acidic. Bleach? That’d be a base.

The pH scale ranges from zero to 14. Anything below 7.0 is considered acidic, while anything above 7.0 is considered alkaline, explains Jennifer Stagg, naturopathic physician and author of Unzip Your Genes: 5 Choices to Reveal a Radically Radiant You. (A pH of seven is considered neutral.)

Depending on their function, certain parts of your body are more acidic or alkaline. Think of it like how your body maintains a certain temperature to work properly. For example, your blood has a slightly alkaline pH of around 7.4, says nutritionist Vanessa Rissetto, R.D. (This helps your body carry out all of the metabolic reactions and processes necessary for it to function properly, says Stagg.) Meanwhile, your stomach is very acidic (anywhere from 1.5 to 3.5) because it has to break down food, says Rissetto.

Should The pH Scale Influence Your diet?

That’s where the concept of the alkaline diet comes in. The fad, beloved by celebs, is based on the idea that eating certain foods and avoiding others can help your body (specifically your blood) maintain a health-promoting pH.

Here’s the thing: The logic falls flat. The theory that chowing down on high-alkaline foods to help regulate your blood’s pH is totally incorrect, says Rissetto. “Food can’t change the acidity or alkalinity of your blood,” she says. Why? Just like your body works to maintain a proper body temperature, it also regulates the pH of your blood. (Remember the term ‘homeostasis?’ If not, it’s the state of balance in which your body functions at its best.)

What your diet can determine, however, is the pH of your urine, she says. There may be some benefit to having urine that’s slightly alkaline, such as a potentially lower risk for kidney stones, according to Stagg. But that whole homeostasis thing applies here, too: Highly acidic urine can be a sign of uncontrolled diabetes, while highly alkaline urine can indicate a UTI or kidney failure, says Rissetto.

The Alkaline Diet Menu

Still, the alkaline diet is pretty dang popular—and can be pretty dang healthy, too. On the diet, you eat tons of fruits, veggies, nuts, and seeds that have high pHs. Spinach, kale, leafy greens, broccoli, avocado, celery, and cucumber are some of the most alkaline foods out there, says Stagg. Meanwhile, foods like artichokes, Brussels sprouts, cauliflower, leeks, peas, pumpkins, onions, watercress, and summer squash, are more mildly alkaline, says Rissetto.

Off the menu are acidic foods like eggs, dairy, meat, most grains, alcohol, and caffeine. (Soy, which is high alkaline, is one of the main protein sources on this diet.) The alkaline diet is similar to a vegan diet in that it’s plant-based and pretty restrictive, says Stagg.

Related: 7 Plant-Based Protein Sources

Alkaline Foods And Your Health

Alkaline diet advocates have suggested that the benefits of eating this way include everything from weight loss to less chronic pain to a lower risk of high blood pressure. The thing is, though, it’s not the foods’ high pHs that are responsible for these health benefits. It’s the fact that they’re plants.

Plant foods are generally packed with important nutrients, like vitamins, minerals, and antioxidants. “Large-scale studies on plant-based diets have shown improved outcomes on most measures of chronic disease like cardiovascular disease and certain types of cancer,” says Stagg.

And the weight loss? Also credited to the fact that the foods allowed on the alkaline diet are incredibly healthy, says Rissetto. (They also tend to pack a lot of fiber, which helps you feel fuller for longer.)

There are even alkaline-branded waters, which often add minerals like potassium and magnesium (which are high-alkaline) added, says Stagg. Again, the pH levels of these minerals don’t matter, but our body does need the minerals for optimal function, especially after losing them through sweat during exercise, she explains

Plus, the restriction of processed foods (and the added sugars in them) on the alkaline diet also benefits our health. Case in point: A study published in JAMA Internal Medicine found that those who got more than 10 percent of their daily calories from added sugar had a higher risk of dying from heart disease than those kept their consumption of the sweet stuff low. So, alkaline diet or not, passing on candy bars and soda is just a good idea.

The Bottom Line

Your body can take care of its various pH levels perfectly fine on its own, thank you very much, but incorporating aspects of an alkaline diet—like loading up on fresh fruits and greens—into your daily life certainly can’t hurt.

Related: Finds a greens supplement to up your intake of the good stuff.