CerefolinNAC (CFLN-NAC) is a prescription medical food reported to help with mild to moderate cognitive impairment [Pamlab 2017]. It contains L-methylfolate calcium (6mg), methylcobalamin (2mg), Schizochytrium (90.3mg), and N-acetylcysteine (NAC) (600mg) [Pamlab 2017]. However, dysgeusia secondary to CFLN-NAC therapy has not heretofore been described.

A 64 year-old female presented with an eight year history of progressively decreased ability to smell and taste of unknown origin. CFLN-NAC was prescribed off-label to treat her hypogeusia and hyposmia. Three days after treatment initiation, her taste sensations gradually returned and she was able to describe food as bitter, salty, sour and sweet. Also, she was able to decipher the taste of different nuts, such as almonds, macadamia, pecans, and peanuts at baseline. However, her taste sensations became distorted and she was unable to distinguish specific foods. She reported that most food tasted bland, but she was still able to sense textures of various foods describing them as, “crunchy, but without taste.” She denied any oral pain, xerostomia, hot flashes, and psychological distress. CFLN-NAC was continued for three months and her hypogeusia improved from 20% to 80%. Her dysgeusia persisted, but remitted once CFLN-NAC was discontinued.

Abnormalities in physical examination: General: scalloped tongue, decreased blink frequency, and hypokinesia. Cranial Nerve (CN) Examination: Olfaction (CN I) Testing: Alcohol Sniff Test: 8 (hyposmia). Pocket Smell Test: 2 (hyposmia). Olfactometer Identification Test: Left: 5 (anosmia); Right: 12 (hyposmia). CN III, IV, VI: saccadization on horizontal eye movement. Motor Examination: hypokinetic movements and 1+ cogwheel rigidity in bilateral upper extremities. Drift Test: bilateral abductor digiti minimi signs with cerebellar spooning. Reflexes: absent patellar and Achilles bilaterally. Hoffman’s Reflex: present bilaterally. Other: Magnetic resonance imaging (MRI) of the brain with contrast was unremarkable.

When treating taste impairments, vitamins and minerals have been found to enhance the effect of non-injured nerves, but they do not repair damaged nerves. The presence of a scalloped tongue may suggest nerve injury of unknown proportion, and can either diminish or alter taste. CFLN-NAC may have enhanced the gustatory stimulus of the non-injured nerves. This transient increase could have either caused her dysgeusia or possibly unmasked the dysgeusia secondary to a scalloped tongue. Notable impairments found in her exam evince Parkinson’s disease as a possible etiology, but structural abnormalities were not seen on brain MRI, making this unlikely. Conversely, the relatively rapid resolution after terminating CFLN-NAC strongly suggests that this is not merely a coincidence, but rather an origin. Those initiated on CFLN-NAC should be queried for new onset of dysgeusia and warrant other treatment options.

Funding Acknowledgements: Smell & Taste Treatment and Research Foundation