Low blood levels of the enzyme alkaline phosphatase are most frequently related to malnutrition, reports WebMD. Celiac disease, a form of gluten hypersensitivity, can lead to malnutrition and a concomitant decrease in alkaline phosphatase levels. Scurvy, caused by insufficient intake of vitamin C, also reduces levels of alkaline phosphatase.
Other conditions that lead to low alkaline phosphatase levels include zinc deficiency, protein deficiency, hypophosphatasia and Wilson's disease, notes LabTestsOnline.org. Hypophosphatasia is a rare genetic disorder of bone metabolism that can cause extremely low levels of alkaline phosphatase. Insufficient intake of vitamin B-6 and folic acid are also related to low levels of alkaline phosphatase, states Dr. Jeremy E. Kaslow.
Certain medical procedures such as blood transfusions and heart bypass surgery can temporarily lower blood levels of alkaline phosphatase. Some drugs may also affect the amount of alkaline phosphatase in the body. Oral contraceptives are known to suppress levels of alkaline phosphatase in the blood. The normal concentration for a healthy adult is between 25 and 100 units per liter of blood, according to Healthline. In children, blood levels of alkaline phosphatase may be as high as 350 units per liter. Pregnant women also exhibit higher levels of alkaline phosphatase. A value below 25 units per liter in a normal adult indicates insufficient alkaline phosphatase.