Apple juice doesn’t taste very acidic, but it does retain the raw apple’s acids. These acids are active in your body, where they help produce energy and support metabolism. As long as your apple juice is 100-percent unsweetened juice, it contributes to your daily fruit intake. But don’t drink too much juice because it doesn’t contain the fiber you’ll get from raw apples, and prolonged exposure to the acids can erode tooth enamel.

Apple Juice Acidity

Apple juice has about the same level of acidity as orange juice, but it doesn’t have the same acidic bite because the two have different acid profiles. The primary acid in orange juice is citric acid, while apple juice is high in malic acid, which tastes less bitter than citric acid 3.

Even though apple juice contains about six acids, only a few are present in significant amounts, according to a 2005 report in the Journal of Food Composition and Analysis 2. After malic acid, the next most predominant acids are quinic and chlorogenic acids, followed by a small amount of citric acid 3.

Malic Acid Boosts Energy

When cells in your body produce energy, they follow a step-wise chain of reactions. Each step requires the interaction of specific compounds before the next step can begin. All steps must be completed in order to synthesize energy. Malic acid is needed to complete one of the steps 3. Because malic acid has such an essential job, your body makes its own rather than relying on dietary sources 3.

Malic acid shows promise for treating calcium kidney stones, reported the Journal of Endourology in February 2014 34. It’s also used together with magnesium to help reduce pain caused by fibromyalgia and to relieve the exhaustion of chronic fatigue syndrome 5. More research is needed to verify malic acid’s ability to improve all of these health conditions, however 3.

Quinic Acid Supports Metabolism

Quinic acid is the second most abundant acid in apple juice. When healthy volunteers took quinic acid, researchers at Lund University in Sweden found that levels of nicotinamide and tryptophan also increased, according to an article in Phytotherapy Research in March 2009 7.

Nicotinamide is the form of niacin the body uses to make enzymes that metabolize carbs, fats and protein. The amino acid tryptophan is converted into serotonin, which helps regulate mood and sleep cycles 7.

Chlorogenic Acid for Diverse Benefits

Your cup of apple juice also contains chlorogenic acid, which is an antioxidant naturally produced by plants. Chlorogenic acid is the subject of ongoing studies because it's one of the primary acids found in coffee.

When chlorogenic acid was given to laboratory mice, they lost weight and their levels of triglycerides went down, according to a report in Food and Chemical Toxicology in March 2010. Chlorogenic acid also shows promise for lowering the risk of diabetes by preventing peaks in blood sugar, according to studies cited in Evidence-Based Complementary and Alternative Medicine in August 2013.