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An alkaline diet touts impressive health benefits but unraveling it can be a bit tricky. Is it worth your time? Our nutritionist breaks down the science.

An alkaline diet (also referred to as a pH diet, acid-based diet, or acid-alkaline diet) has become a popular eating approach, and to fully understand the concept behind it, you’ve got to think back to middle school chemistry class when you learned about the pH scale. Used to indicate how acidic or basic a substance is, the pH scale ranges from 0 to 14—with 0 being the most acidic and 14 being the most basic or alkaline. For reference, lemon juice has a pH around 2, baking soda around 9, and blood at 7.4.

What is an Alkaline Diet?

The premise behind alkaline diets is that when foods are consumed and broken down for energy, the leftover residue or ash is either acidic or basic. It’s this ash that alters the body’s internal environment and pH level. Proponents suggest that people today overconsume acid-producing foods. The result is that the ash from these foods creates an acidic environment which lowers the body’s pH increasing susceptibility to weight gain and chronic diseases. An alkaline diet advocates eating foods that leave a more basic or alkaline ash to reduce acidity and to neutralize the body’s internal environment.

Alkaline Diet Food List

Photo: Victor Protasio

The goal of alkaline diets is to reduce intake of acid-producing foods and increase intake of more basic or alkaline-producing foods. However, this isn’t as simple as it may seem because a food’s pH value doesn’t determine a food’s effect in the body. In fact, foods often associated as being “acidic”—such as citrus fruits and tomatoes—actually have an alkaline effect in the body.

Instead, you have to look at a food’s potential renal acid load (PRAL) to determine a food’s effect in the body. PRAL is a measure of how a food affects the pH of urine that the kidneys excrete. Foods that increase pH are considered more alkaline, and should be your predominant food choices to keep the your body from being too acidic. Here’s a general breakdown of food groups:

Foods with an alkaline or acid-reducing effect

  • Vegetables and fruits
  • Some nuts and legumes
  • Most whole and sprouted grains

Foods with acidic or acid-producing effect:

  • Red meats, processed meats, poultry and fish
  • Fried foods
  • Refined grains and refined grain or yeast-based products
  • Food and drink with added sugars

Most alkaline diets suggest that 80% of a person’s food intake should consist of alkaline foods, while acid-producing foods can make up the other 20%. Foods that tend to have no effect on acidity—like oils, butter, egg whites, whole milk and some dairy like cottage cheese—are okay to consume in moderation.

Potential Benefits of an Alkaline Diet

Research continuously points to eating a more plant-based diet for overall health and disease prevention, and plant foods like vegetables, fruits, legumes, nuts, and whole or sprouted grains are the staple components in alkaline diets. These foods are also packed with nutrients for minimal calories, which could also help with weight loss and management. Another positive health benefit of following an alkaline diet is eating less high-fat meats, processed meats, added sugars, fried foods, and refined grain products, all of which have been suggested to minimize health risks.

Alkaline Diet Misconceptions

Nutrient concerns usually dominate this section of my diet reviews (i.e. the Military Diet), but this isn’t the case with alkaline diets. Instead, my biggest concerns are the misconceptions and faulty science associated with alkaline diets. Here are three of the biggest ones.

You Can Change the pH of the Body.

Your body’s pH holds steady at 7.4, and it has numerous feedback mechanisms to ensure this is very tightly maintained. Various areas within the body have different pH levels to function effectively. (The stomach’s acidic digestive juices are an example; acid is needed in the stomach to initiate protein digestion and kill harmful microbes.) But even while this is going on, the blood’s pH stays at 7.4, and the foods consumed do not change that. Foods may affect the pH of urine that is produced, but urine pH isn’t used as a measure of the body’s pH.

You Need to Test Urine to Measure the Body’s pH.

Alkaline diets often suggest buying urine test strips to monitor the pH of the body, but as explained above, the pH of urine isn’t a measure of the body’s pH level. Testing urine may give you a good indication when you have eaten foods with a greater PRAL because the pH will likely indicate greater acidity. However, unless someone suffers from a kidney condition, I’m not really sure why this is necessary or how this information is useful—and no, you shouldn’t consume a spoonful of baking soda to neutralize your urine’s pH, as one alkaline diet suggested.

Cancer Cells Grown in Acidic Environments.

Alkaline diets promote the idea that acidity in the body causes cancer, a theory that stems primarily from research looking at individual cells in varied pH environments in a lab. But, there are no studies directly linking foods that have an acidic effect in the body with cancer. In fact, the American Institute for Cancer Research says that “the acidity or alkalinity of foods is not important” in terms of cancer prevention. And there’s limited research to suggest that eating a more alkaline diet has much impact on health at all. Yes, research suggests that diets high in plant foods are correlated with reduced risk of various cancers, as well as other chronic diseases. But, these risk reductions are associated with the antioxidants, phytochemicals and fiber in plant foods—not because these foods create a more alkaline environment in the body.

Bottom Line

Most all Americans would benefit from eating more plant foods—not to mention drastically cutting down on red meat, fast food, and added sugars—so the food choices encouraged in alkaline diets are healthy.

However, an alkaline diet takes healthy eating and makes it more complicated than it has to be. The bulk of research says that health benefits from plant foods like fruits, vegetables, and nuts stem from their nutrients and disease-fighting compounds–not from their alkalizing effect. My take from research is to keep emphasizing a more plant-centric diet, and don’t waste time worrying about your body’s pH—especially by using urine test strips!

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