"It is of use from time to time to take stock, so to speak of our knowledge of a particular disease, to see exactly where we stand in regard to it, to inquire what conclusions the accumulated facts seem to point to, and to ascertain in what direction we may look for fruitful investigations in the future." Sir William Osler
The cause and management of "dry eyes" challenge ophthalmologists and primary care physicians. This symptom was unexpectedly and repeatedly encountered among patients manifesting other reactions to products containing aspartame, a sweetener currently being consumed by 54% of adults in the United States. This complaint was encountered in both the routine questioning of apparent aspartame reactors and a computerized, 9-page survey of such individuals. Many also volunteered difficulty in wearing contact lenses due to decreased tears, dry mouth (xerostomia), joint pains, confusion and memory loss - all specifically attributed to the use of aspartame products.
The completed questionnaires were analyzed with the assistance of the Management Information System staff at the Good Samaritan Hospital, West Palm Beach, Florida.
The causative or contributory role of aspartame was indicated by these clear-cut clinical correlates: (1) prompt and gratifying improvement of ocular and other symptoms following the cessation of aspartame, generally within several days; and (2) their recurrence shortly after resuming such products. This sequence predictably recurred after rechallenge with aspartame, known or inadvertent.
These observations have been duplicated by more than a score of patients complaining of dry eyes in subsequent aspartame reactors. There were related problems. For example, a physician who consumed considerable diet sodas developed a type of corneal dystrophy generally associated with the chronic use of certain drugs (e.g., indomethacin).
Computerized correlations between aspartame-associated dry eyes, and "marked memory loss," "severe depression" and "severe mental confusion" were done on the first 362 aspartame reactors who completed the questionnaire. (There was a 30.8% response to the initial mailing of 1,177 forms.) The correlates were as follows:
Other complaints offered by the larger cohort had considerable significance, with particular reference to the Sjogren syndrome. They included excessive thirst due to dry mouth (xerostomia) in 65 (12%), and severe joint pains in 58 (11%). It is noteworthy that three-fourths of patients in this and the large series of aspartame reactors were women averaging 50 years, a phenomenon also encountered in the Sjogren syndrome.
Case 2 - A 36 year-old businesswoman complained of recent difficulty wearing contact lenses. She had been consuming considerable amounts of soft drinks and gum containing aspartame. These and other symptoms - including lightheadedness, headache and leg cramps - abated within two weeks after all aspartame products were avoided.
Case 3 - a 61 year-old female court reporter developed dry eyes and bilateral blurring of vision. Other recent complaints included marked memory loss, severe headache, dizziness, extreme irritability, and atypical facial and joint pains. As a result, she had been making many errors at work. The patient improved "immediately" when she ran out of aspartame-containing beverages, and resumed regular sodas. She therefore deduced that aspartame products had been causing her problems. Her previous daily consumption included 4 cans of aspartame soft drinks, 2 glasses of aspartame hot chocolate, and 6 packets of an aspartame tabletop sweetener.
Two reactors who complained of "thick saliva" developed enlargement and tenderness of the parotid glands. The secretory structures of the salivary glands presumably had been affected by aspartame, as well as the lacrimal glands. The affinity of aspartame for salivary glands were demonstrated experimentally by the prompt uptake of isotopically-labelled aspartame.
The Sjogren or sicca syndrome affects an estimated 2% of the adult population. The reduction or absence of lacrimal and salivary secretions results in dry eyes and dryness of the mouth. (The diagnostic lipstick-on-teeth sign consists of lipstick adhering to the upper front teeth). This disorder is presently regarding as a chronic autoimmune disorder resulting from lymphocyte-mediated destruction of these glands and changes in the points.
A vicious cycle is likely to ensue if considerable aspartame-containing beverages are consumed because of the intense thirst created by severe dryness of the mouth. Weiffenbach et al. demonstrated that taste impairment is not a necessary consequence of salivary gland dysfunction among patients with "dry mouth" caused b the chronic absence of saliva. Accordingly, such individuals may come to prefer the taste of aspartame in satisfying their chronic thirst, with perpetuation of the sicca syndrome.
The systemic and central nervous system sequelae of the Sjogren syndrome underscore the potential importance of these findings. Cognitive impairment and lamenting features have been reported by one-fourth of Sjogren patients. Severe confusion and memory loss also were noted in 157 (28.5%) aspartame reactors in the present series. Indeed, many reactors in their third and fourth decades asked, "Could I be developing early Alzheimer's disease?" The prompt and impressive regression of their confusion and memory impairment after abstinence from aspartame proved reassuring.
Several phenomenon may explain cerebral dysfunction associated with aspartame use. They include flooding of the brain with large amounts of phenylalanine (50% of the aspartame molecule), disturbances of neurotransmitters (especially dopamine), other effects of its three chemical components (phenylalanine, aspartic acid, methanol), methanol-induced cerebral edema, and glucopenia due to increased insulin release and concomitant decreased food intake in an attempt to lose weight.