With the exception of pure water, which is neutral, all food is either acid-forming or alkaline-forming when metabolized in the body. Consuming a diet that emphasizes alkaline-forming foods over acid-forming foods helps support a balanced body pH, or the state of homeostasis necessary for bodily function and optimal health. Many highly acid-forming foods, such as baked goods and processed foods, supply little more than empty calories while temporarily increasing the body's acid load. Other slightly to moderately acid-forming foods, including most nuts, many whole grains and a few fruits, are nutrient-dense, health-promoting components of a balanced diet.
Cranberries are rich in quinic acid and contain significant amounts of malic and citric acids. This high acid content translates to a low pH — freshly extracted, unsweetened cranberry juice is valued between 2.3 and 2.5 on the pH scale, depending on the fruit’s state of ripeness. Comparatively, fresh lemon juice is similarly acidic, with an average pH of 2.3. Fresh lime juice is slightly more acidic, valued between 1.8 and 2.0, and fresh grapefruit juice is slightly less acidic, with a pH value of 3.0. The freshly extracted, unsweetened juices of oranges and pineapples are less acidic among the common fruit juices, each having a median pH value of about 3.6.
Metabolic Process and pH
A food’s acid content doesn’t determine whether it becomes acid or alkaline forming — its pH nature in the body is a product of the metabolic process. Often, a food's acid content contrasts its effect in the body. For example, whole eggs are alkaline, but they’re moderately acid-forming in the body. Similarly, chocolate cake has an alkaline pH, but is highly acid-forming in the body. Angel food cake and watermelon have a comparable, slightly acidic pH range of about 5.2 to 5.6. In the body, however, watermelon is highly alkaline-forming, while angel food cake is highly acid-forming. Most citrus fruits are acidic, but have an alkaline effect in the body. Cranberry juice itself is very acidic, but it’s only moderately acid-forming in the body.
Most fruit is alkaline-forming in the body. Cranberries, dates, plums, pomegranates and prunes are the exceptions — all are slightly to moderately acid-forming. Cranberries, plums and prunes are acid-forming in the body because the types of acids they contain convert to hippuric acid in the liver, which cancels out the alkalizing effects of the sodium, magnesium and potassium present in these fruits. All of the most alkaline-forming fruits contain high to moderate amounts of acids, but these acids don’t negate the effects of the alkalizing compounds. Highly alkaline-forming fruits include watermelon, cantaloupe, honeydew melon, papaya, mangoes, figs, kiwi fruit, lemons, limes, pineapple, apples, blackberries, strawberries, raspberries, peaches, apricots, pears, oranges, tangerines and bananas.
Cranberry juice is useful in preventing urinary tract infections because cranberries contain proanthocyanidins, or PACs, which prevent bacteria — including E. coli, the bacteria responsible for up to 90 percent of urinary tract infections — from adhering to and infecting the urinary tract. Adding sugar to cranberry juice cuts its acidity by increasing its pH value because the pH of refined sugar is much less acidic than that of cranberry juice. However, adding sugar to cranberry juice makes the juice highly acid-forming in the body because sugar is highly acidifying. Instead, cut the acidity in cranberry juice with unsweetened apple cider or unsweetened apple juice, both of which are alkaline-forming.
- “Encyclopedia of Healing Foods”; Michael Murray et al.; 2005
- “Acid Alkaline Food Guide”; Dr. Susan Brown et al.; 2006
- “The pH Balance Diet”; Bharti Vyas et al.; 2007
- “Alkalize or Die”; Dr. Theodore Baroody; 1991
- Oklahoma State University: The Importance of Food pH in Commercial Canning Operations
- Stockbyte/Stockbyte/Getty Images
This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or JillianMichaels.com.