When metabolized, all foods produce alkalizing or acidifying compounds that temporarily and minutely affect the body’s homeostasis. A food’s acid content isn’t indicative of its pH nature in the body. Eggs, for example, have slightly alkaline, or basic, pH values, but are acid-forming in the body. Likewise, many high-acid foods — including tomatoes — are moderately to highly alkalizing in the body. A diet that regularly emphasizes alkaline-forming foods, such as tomatoes, supports the body’s natural state of alkalinity and contributes to important alkali reserves.
Acid Content
The pH scale, which runs from 0 to 14, values the acid content of a substance relative to other substances. Pure water has a neutral value of 7, while alkaline substances have higher values, and acidic substances have lower values. The organic acid content of most vegetables, fruits, grains, dairy products, meat, poultry and fish is high enough to give them pH values in the acidic range. Foods with values between 4.6 and 7 are considered low-acid, while high-acid foods have values below 4.6. Depending on state of ripeness, the pH of a fresh red tomato can range from 4.2 to 4.9. Riper, juicier tomatoes are more acidic and have lower pH values.
Metabolic Process and pH
The metabolic process affects a food’s pH nature in the body. Almost all vegetables, for example, have slightly acidic pH values but are alkaline-forming in the body. This is because most vegetables and fruits contain potassium citrate, a mineral compound that’s metabolized into potassium bicarbonate, which is a good source of alkalizing bicarbonate, according to “The Acid Alkaline Food Guide.” The compounds produced by alkalizing foods, including tomatoes, help maintain the proper, distinctive pH values of all bodily fluids. Healthy, oxygen-rich arterial blood has a slightly alkaline pH range of 7.35 to 7.45, while the pH of urine and saliva can fluctuate from about 5 to 8, or higher, throughout the day.
Chronic Acidosis
Cells and tissues require a slightly alkaline environment to function properly. When you eat acid-forming foods, your body uses alkaline compounds to buffer and remove the excess acids. These alkaline compounds can come from alkalizing foods eaten in the same meal, or from your body’s alkaline reserves. The body has a limited capacity for acid removal each day, so a diet rich in acid-forming foods can cause acid buildup in tissues, where it's stored for later removal. Diets rich in acid-forming foods, including processed foods, meat, dairy products, alcohol, coffee and most grains, can deplete critical alkaline reserves over time, causing a more serious acid buildup known as chronic low-grade metabolic acidosis. This condition can set the stage for diseases and conditions including cancer and chronic fatigue, according to “The Encyclopedia of Healing Foods.”
Considerations
Several factors influence the alkalizing potential of alkaline-forming foods. Riper, juicier tomatoes are more alkaline-forming in the body than less ripe fruits. Similarly, overripe tomatoes are slightly less alkalizing than those at the peak of ripeness. Refrigeration slightly diminishes alkalizing potential, as does cooking. Organic tomatoes are more alkaline-forming than conventional varieties, because pesticides reduce the alkalizing nature of all foods. Most vegetables, fruits and herbs, in addition to a few grains, legumes and nuts are alkaline-forming in the body. A diet of 70 to 80 percent alkaline-forming foods helps prevent acid overload and maintain a balanced body pH.
References
- “The Encyclopedia of Healing Foods”; Michael Murray, N.D., et al.; 2005
- “The pH Balance Diet”; Bharti Vyas, et al.; 2007
- “The Acid Alkaline Food Guide”; Dr. Susan E. Brown, et al.; 2006
- Oklahoma State University: The Importance of Food pH in Commercial Canning Operations; William McGlynn
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