PH: Acid vs. Alkaline: What’s the Big Deal? Acidity and alkalinity is measured on the pH scale, which ranges from 1 to 14. Our blood is very tightly maintained at a pH between 7.35 and 7.45, slightly alkaline. Very small fluctuations can occur, but if the blood moves out of this range in either direction very serious health problems occur. The ONLY foods that create alkalinity in the body are vegetables and fruits. That’s it. ALL other foods create acidity on some level.