Alkaline phosphatase, or ALP, refers to a type of enzyme that can be found in all forms of human tissue. This substance comes in several varieties that differ in their chemical composition, depending on which part of the body they are manufactured in, though it is chiefly found in your liver and bones. ALP is involved in many different biochemical reactions; if you have lower than normal levels of alkaline phosphatase, this may potentially indicate a health issue or genetic condition.
Protein and Calorie Deficiencies
One of the chief causes of lowered alkaline phosphatase levels is malnutrition and low caloric intake. Other disorders that lead to a specific deficiency in nutrients such as protein, vitamin C, folic acid, or vitamin B-6 can also directly lower your ALP. Conditions that can cause these deficiencies include celiac disease, scurvy, gastrointestinal absorption disorders and hypochlorhydia, as well as maintaining an unbalanced diet in general.
Hypophosphatasia
Hypophosphatasia is a rare genetic condition involving deficient ALP activity. Mutations in the gene that governs ALP synthesis cause the body to produce an abnormal version of the enzyme. This leads to low ALP activity and levels. And since abnormal ALP cannot be used in critical biochemical processes such as mineralization, patients tend to have weakened bones and teeth. Some also have skeletal abnormalities, respiratory problems and high levels of calcium in the blood, which can be life-threatening for infants and young children.
Cardiac Surgery and Other Reasons
In a study published in 1995 in "Clinical Chemistry," male participants who underwent cardiac surgery and used a cardiopulmonary bypass pump were particularly prone to lowered ALP levels. Cardiac surgery patients experienced an average drop of around one-half their total ALP levels before surgery. Other reasons for lowered ALP include blood transfusions, pernicious anemia, and a mineral deficiency in the body's levels of zinc or magnesium, MedlinePlus reports.
Testing ALP Levels
Since measuring alkaline phosphatase depends on taking a blood sample, it is often done simultaneously with a conventional blood test or with several other tests called a liver panel, as Lab Tests Online reports. ALP levels usually go up immediately after eating, especially if you've eaten fat-laden foods; therefore, you will be asked to refrain from eating and drinking for 10 hours prior to the test. Aside from this, no other special preparation is needed. Certain medications can interfere with accurate measurement, so be sure to inform your doctor prior to the test. An ALP level of 25 to 100 U/L is considered normal for adults. Children have a higher requirement, around 350 U/L, due to rapid bone growth.
