Jewish World Review July 16, 2002 / 7 Menachem-Av, 5762
Dr. Ed Blonz
Dear L.B.: Sulfites are effective preservatives against bacteria and molds. They can also help prevent discoloration (oxidation) in some foods, be used as a dough conditioner, discourage unwanted growth of microorganisms in wine, and help maintain the stability and potency of certain medications. Sulfite preservatives include sodium sulfite, potassium sulfite, sodium metabisulfite, potassium metabisulfite and sulfur dioxide.
In the past, they were commonly used to keep fruits and vegetables looking fresh, and they are currently used in dried fruits to allow a longer shelf life. Without sulfiting agents, fruit would need to be dried to a leather-like consistency to assure protection against mold.
Sensitivity to sulfite preservatives can develop at any point in life, and, if you are sensitive, eating food with sulfites might cause headaches, hives or shortness of breath. Sulfites are safe for most people, but the Food and Drug Administration estimates that one out of 100 people is sulfite-sensitive, and that 5 percent of those who have asthma are at risk of suffering an adverse reaction to sulfites.
In response to consumer concerns about sulfite sensitivity, the FDA has banned their use on fresh fruits and vegetables (except potatoes), but they are still used in dried fruits, beer and wine. If sulfiting agents are present, food manufacturers must disclose this fact on the label. When foods are sold in bulk, it is the store manager's responsibility to see that there is some sort of sign or label to indicate when sulfites have been used in a particular product.
Caution makes sense for those with sulfite sensitivity -- particularly those who have asthmatic reactions. The appropriate medications should be on hand when eating out or trying new foods.
DEAR DR. BLONZ: Is there any scientific information on tupelo honey? The article posted on the Internet by the manufacturing company claims that the honey's high levulose/low dextrose ratio makes it safe for some diabetics to eat it. I wonder if there has been any research on these claims. -- N.G., Carlsbad, Calif.
Dear N.G.: Levulose is another name for fructose (fruit sugar), and dextrose is the same as glucose (human blood sugar). Most honeys have more fructose than glucose, but it would appear that tupelo honey tends to have more fructose than other varieties.
Does this make it safer for diabetics? It's doubtful. There is no magic (or science) here. Adjustments can be made for a small amount of honey when it's used as a minor ingredient, but a simple sugar such as honey -- whether it is tupelo honey or clover honey -- can have a dangerous impact on a diabetic's blood-sugar level. Those with type 1 (insulin-dependent) diabetes need to be especially wary. If you have specific questions for your particular situation, it would pay to consult with a registered dietitian.
DEAR DR. BLONZ: One cup of cooked potatoes (150 grams, or about 3.5 ounces) is supposed to contain about 15 milligrams of vitamin C. This amount is what should be in baked potatoes or French fries, according to the U.S. Department of Agriculture. The nutritional authorities with whom I have checked tell me that heat destroys vitamin C, yet cooking baked (and French-fried) potatoes exposes them to a lot of heat. Are these "heated" potatoes still a good source of vitamin C? I would appreciate your comments regarding this inconsistency. -- V.J., Mill City, Ore.
Dear V.J.: The intense heat involved in the preparation process does indeed destroy a number of vitamins, including vitamin C and thiamin (vitamin B1). There is no apparent inconsistency here, as the USDA figures reflect about a 50-percent reduction of the amount of vitamin C found in a raw potato. Baked potatoes and French fries have about the same amount of vitamin C.
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