From the Research
Low alkaline phosphatase (ALP) levels in the blood indicate decreased activity of this enzyme, which is normally produced by the liver, bones, and other tissues, and may signal hypophosphatasia, a condition that can be misdiagnosed as osteoporosis and incorrectly treated with antiresorptive therapy, as seen in a study published in 2023 1.
Causes and Symptoms
The condition, called hypophosphatasia, can be caused by several factors including genetic disorders, malnutrition (particularly zinc, magnesium, or vitamin B6 deficiency), certain medications (like bisphosphonates), hypothyroidism, or protein deficiency.
- In children, low ALP can be particularly concerning as it may indicate a rare inherited disorder that affects bone development.
- For adults, mild decreases in ALP are often not clinically significant, but persistent low levels warrant further investigation. Some symptoms associated with low ALP may include:
- Bone pain
- Fractures
- Dental problems
- Fatigue, as reported in 37% of patients in a study published in 2020 2
- May be completely absent depending on the underlying cause
Diagnostic Approach
If you have low ALP levels, your doctor may recommend additional tests to determine the cause, including:
- Genetic testing
- Vitamin level assessments
- Bone density scans A diagnostic approach to patients with low serum ALP was discussed in a study published in 2023, which suggested measuring several ALP substrates, such as pyrophosphate, pyridoxal phosphate, or phosphoethanolamine, to establish enzyme deficiency 3.
Treatment
Treatment depends on identifying and addressing the underlying cause, which might involve:
- Nutritional supplementation
- Medication adjustments
- Specific therapies for genetic disorders Low ALP itself is not treated but rather serves as an important diagnostic indicator. A study published in 2024 highlighted the importance of recognizing low ALP levels, even in patients with normal total ALP levels, as seen in a case of hypophosphatasia with normal alkaline phosphatase levels 4.
Clinical Significance
The prevalence of persistent low ALP in a clinical setting is 0.13%, and the recognition is very low (3%), as reported in a study published in 2016 5. It is essential to recognize low ALP levels to provide appropriate care for patients and avoid antiresorptive treatment, which can be harmful in cases of hypophosphatasia. A study published in 2023 found that persistently low ALP in osteoporosis clinic attendees is easy to identify and signals the possibility of hypophosphatasia, a condition that may be mistaken for osteoporosis and incorrectly treated with antiresorptive therapy 1.