The pH scale expresses hydrogen ion concentration, which makes a substance or environment more acidic or alkaline, on a scale of 0 to 14. Seven is neutral on the scale and lower than seven — which indicates a high hydrogen ion concentration — is acidic. Ideally, your blood should stay close to its natural pH of between 7.35 and 7.45. However, acidic foods can affect the blood’s pH and your risk of various health problems.
What Are Acidic Foods?
Acidic foods form acid in your body when they are metabolized, or broken down. It’s more accurate to refer to them as acid-forming foods to avoid confusion with foods that have a high acid content — such as lemons — but which are alkaline-forming when you consume them. The typical American diet is rich in acid-forming foods, when it would be more healthful to be between 50 and 75 percent alkaline.
Effects of Acidic Foods
When acidic foods lower the pH of your blood and body, inflammation levels rise and damage your cells, tissues and organs. Either extreme — too much acidity or alkalinity — makes your body more vulnerable to illness and disease, according to nutritionist Cherie Calbom, co-author of “Juicing, Fasting and Detoxing for Life.” She notes that consuming too many acid-forming foods contributes to health problems such as joint pain, osteoarthritis, and osteoporosis.
Acidic and Alkaline Foods
Chances are that many of your favorite foods are considered acidic foods. They include meat and animal products, such as milk, cheese and cream. Refined carbohydrates such as sugar and white flour, whole grains, fried foods and many fruits are also acidic foods. So are fried foods, junk food, coffee, tea, soda and alcohol. On the other hand, vegetables, nuts, seeds, healthy oils such as olive and flax seed, citrus fruits and most legumes are alkaline-forming foods.
It’s quite difficult to permanently change the pH of your body, according to Karina Christopher, a registered dietitian with the University of Kentucky Markey Cancer Center. Organs such as your liver and kidneys work overtime to restore your body's natural pH. So you shouldn’t obsess about eating the occasional acid-forming food. The real concern is constantly eating a diet loaded with these foods. Besides their ability to keep your body at a lower pH, most acidic foods — such as meat, dairy products and refined carbohydrates — are key culprits in weight gain, which can lead to related disorders such as obesity, type 2 diabetes and heart disease.
- “Juicing, Fasting and Detoxing for Life”; Cherie Calbom, M.S., et al.; 2008.
- Markey Menu – Nutrition for You: Acidic Foods and Cancer; Karina Christopher; July 2011