Sulfa, Sulfites, Sulfur – Which Is Which! I’m Allergic To One Of Them…
We often hear people tell us in somber, deathly serious tones “I have to be really careful – I’m allergic to sulfur. I took a sulfa drug once and the doctor told me if I ever took it again I could have a reaction and die!”
It is tragic that so many well-meaning doctors are so woefully ignorant of basic inorganic and organic chemistry – they must have skipped those classes – and they have terrified generations of patients with their unfounded warnings.
Let’s look at the truth about these substances:
Sulfur (chemical symbol: S) is a naturally occurring non-metallic element that comprises 0.25% of the human body. It is the 8th most prevalent element in the body. (1)
Elements found in the human body at their approximate amounts:
- Oxygen (65%)
- Carbon (18%)
- Hydrogen (10%)
- Nitrogen (3%)
- Calcium (1.5%)
- Phosphorus (1.0%)
- Potassium (0.35%)
- Sulfur (0.25%)
- Sodium (0.15%)
- Magnesium (0.05%)
- Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine, Manganese, Cobalt, Iron (0.70%)
- Lithium, Strontium, Aluminum, Silicon, Lead, Vanadium, Arsenic, Bromine (trace amounts)
Sulfur is an essential mineral, meaning that the body MUST have it. Sulfur is found in two amino acids, cysteine and methionine. Methionine is an essential amino acid. (2)
Sulfur is a component of many proteins, vitamins and hormones. Sulfur-containing compounds in humans include methionine, cysteine, homocysteine, cystathione, S-adenosylmethionine (SAMe), taurine, thiamin, biotin, alpha-lipoic acid (ALA), coenzyme A, glutathione (GSH), chondroitin sulfate, glucosamine sulfate, fibrinogen, heparin, metallothionein, and inorganic sulfate. (3)
There is no such thing as a sulfur allergy, just as there is no such thing as an allergy to oxygen , carbon or calcium, all of which also occur in the human body in high amounts. Anyone who was truly allergic to sulfur would find it impossible to live!
Sulfate (SO4) is a molecule which contains sulfur and oxygen. It occurs in nature and is found in most natural water including rain water. It is also the form of sulfur most commonly used to fertilize plants. (4) Sulfate may have a laxative effect that can lead to dehydration, especially in infants. Adults become “acclimatized” to high sulfate levels. (5) The current U.S. EPA national Secondary Maximum Contaminant Level for sulfate, is 250 mg/L (U.S. EPA, 1990).
Sulfite (SO3) is another molecule that contains sulfur. Sulfite is used on foods and some wines as antioxidants, and can cause asthmatic reactions. Sulfites are rare in medications.
Sulfites are used as preservatives on vegetables, especially vegetables in salad bars. This is probably the most common source of sulfite allergy reactions.
Sulfa drugs (for example the sulfonamide class of antibiotics), contain sulfur but allergies and other reactions are not from the sulfur per se. Rather, the complex sulfonamine molecule can form proteins that are allergenic in some individuals. The sulfur atom is NOT the allergenic agent and being allergic to sulfa drugs does NOT imply having an allergy to sulfur.
Sulfa antibiotics include Septra®, Bactrim® and Pediazole®.
So, yes, you may have had a reaction to a sulfa-type drug some time in the past. Many drugs, especially antibiotics of this type, are complex molecules that have plenty of potential to cause allergy-like reactions. And it is quite possible that you are sensitive to sulfites as they are used commonly on vegetables and in wines and many other foods as preservatives. Many people share these sensitivities, to the extent that many products must be labeled to indicate that they contain sulfites.
But is incredibly unlikely for anyone to be allergic to sulfur – it is as important to our lives as water and oxygen!
1. Reference: H. A. Harper, V. W. Rodwell, P. A. Mayes, Review of Physiological Chemistry, 16th ed., Lange Medical Publications, Los Altos, California 1977.
2. Reeds PJ. “Dispensable and indispensable amino acids for humans.” J. Nutr. 130 (7): 1835S–40S, 2000.
3. Parcell Stephen. Sulfur in Human Nutrition and Applications in Medicine. Alternative Medicine Review Volume 7, Number 1 2002.
4. Sulfate -vs- Elemental Sulfur Part I: There Is A Difference. Educational brochure by Agri-Facts ™
5. Wilkes University Center for Environmental Quality, Environmental Engineering and Earth Sciences. “Sulfates and Hydrogen Sulfide -That Rotten Egg / Sulfur Smell – Sulfate Reducing Bacteria “(SRB).
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