Bone Health and Vitamin and Mineral Deficiencies

Anyone who must adhere to a diet that restricts or eliminates natural foodhas the potential to experience vitamin and micronutrient deficiencies. Teens and adults with PKU have also been found to have difficulties with bone health, such as decreased bone mineral density (BMD) and bone strength. The amino acid (AA) formulas and medical foods that were first developed in the 1960s to address the requirements of people with PKU have been improved, but some may not have enough vitamins and minerals. In particular, your levels of vitamins B6 and B12, calcium, folate, and iron may still be deficient if you are not consuming supplements of these vitamins and minerals.

Preventing low bone density is imperative to prevent fragile bones and fractures. The cause of these bone problems are not known, although they are often associated with the low-Phe diet, and are potentially related to the high acidity of the AA formula people with PKU have to consume. Difficulty absorbing protein, calcium, and vitamin D may also cause decreased bone density and strength.

The new dietary guidelines for PKU recommend that your metabolic clinic do a yearly routine biochemical panel to help monitor your health and any changes.  If any of these tests come back abnormal, further testing may be warranted to check for vitamin and mineral deficiencies.  In addition, it is now recommended that you receive a DXA radiological scan every five years.

Some research has also found that people with PKU who drink and eat foods made with glycomacropeptide (GMP) retain more AAs and protein in their blood.