Dr. Ron’s Research Review – February 3, 2010

© 2010


This week’s research review focuses on food additives and sulfites, with molybdenum as the supplement of choice.

Sulfite Sensitivity

Sulfite sensitivity is caused by a relative deficiency of the enzyme sulfite oxidase. According to FDA estimates, only 1% of our population suffers from sulfite sensitivity and those suffering from true sulfur sensitivity is even less than this. (Vally, Misso et al. 2009)

Sulfite sensitivity is a condition characterized by asthma-like symptoms, including wheezing, chest tightness, coughing, extreme shortness of breath, and even loss of consciousness. Other symptoms include flushing, angioedema, itching, hives, contact dermatitis, swelling of eyes, hands and feet, nausea and diarrhea, and anaphylactic shock.

Many people, although not severely sulfite sensitive, will exhibit the “red-wine stuffy nose” after drinking just a single glass of red wine. Others get a characteristic alcohol flush on the face and neck when drinking red wine, beer, or hard liquor. (2006)


Sulfite oxidase is an oxidoreductase class enzyme that catalyzes the reaction from sulfite to sulfate.  This is a mitochondrial molybdohemoprotein meaning molybdenum is a necessary co-factor in the synthesis of this enzyme.  Not enough molybdenum, not enough sulfite oxidase is produced possibly resulting in sulfite sensitivity. (2006)


Articles and Abstracts

Molybdenum – monograph

            (2006) Download

Although molybdenum was first identified as an element over two centuries ago, its biological importance was not appreciated until researchers demonstrated it had a direct role in animal metabolism. Molybdenum has since been identified as an essential trace element for nearly all plants and animals, occurring as a cofactor in three important enzymatic reactions that take place in virtually all forms of life. Clinically, molybdenum deficiency is rare, but inborn errors of metabolism resulting in deficiencies of the molybdoenzymes have been described. Dietary intake of molybdenum is generally sufficient, with legumes such as lentils, beans, and peas being the richest source. Nuts, grains, cauliflower, and leafy vegetables are also good sources, whereas animal products and fruit are low in molybdenum. Molybdenum content of plant-based foods is dependent on the amount of molybdenum in the soil in which they are grown. Molybdenum supplementation may be of therapeutic benefit in patients with molybdoenzyme deficiency, sulfite sensitivity, Wilson's disease, and certain types of cancer, and in those receiving total parenteral nutrition.


Food Additives and Sensitivities

            (Rangan and Barceloux 2009) Download


Clinical effects of sulphite additives

            (Vally, Misso et al. 2009) Download

Sulphites are widely used as preservative and antioxidant additives in the food and pharmaceutical industries. Topical, oral or parenteral exposure to sulphites has been reported to induce a range of adverse clinical effects in sensitive individuals, ranging from dermatitis, urticaria, flushing, hypotension, abdominal pain and diarrhoea to life-threatening anaphylactic and asthmatic reactions. Exposure to the sulphites arises mainly from the consumption of foods and drinks that contain these additives; however, exposure may also occur through the use of pharmaceutical products, as well as in occupational settings. While contact sensitivity to sulphite additives in topical medications is increasingly being recognized, skin reactions also occur after ingestion of or parenteral exposure to sulphites. Most studies report a 3-10% prevalence of sulphite sensitivity among asthmatic subjects following ingestion of these additives. However, the severity of these reactions varies, and steroid-dependent asthmatics, those with marked airway hyperresponsiveness, and children with chronic asthma, appear to be at greater risk. In addition to episodic and acute symptoms, sulphites may also contribute to chronic skin and respiratory symptoms. To date, the mechanisms underlying sulphite sensitivity remain unclear, although a number of potential mechanisms have been proposed. Physicians should be aware of the range of clinical manifestations of sulphite sensitivity, as well as the potential sources of exposure. Minor modifications to diet or behaviour lead to excellent clinical outcomes for sulphite-sensitive individuals.




(2006). "Molybdenum - monograph." Altern Med Rev 11(2): 156-61.

Rangan, C. and D. G. Barceloux (2009). "Food additives and sensitivities." Dis Mon 55(5): 292-311.

Vally, H., N. L. Misso, et al. (2009). "Clinical effects of sulphite additives." Clin Exp Allergy 39(11): 1643-51.