DEAR DR. BLONZ: Are you aware of any research about the health benefits of tupelo honey, particularly in regard to diabetes? An article promoting its use said that its "high-levulose, low-dextrose ratio" makes it safe for people with diabetes. Has there has been any research on that? -- G.N., Anderson, South Carolina
DEAR G.N.: That article uses some less-common names for the substances in question, but that doesn't change things. Levulose is more commonly known as fructose, or fruit sugar, and dextrose is more commonly known as glucose (human blood sugar). Most honey contains fructose and glucose as separate compounds, each known as a monosaccharide (with "saccharide" coming from the ancient Greek for "sugar"). High-fructose corn syrup, and the compound known as invert sugar, are the same in this respect. Table sugar, also known as sucrose, differs from honey because the glucose and fructose are attached as a single compound known as a disaccharide.
Honeys tends to have more fructose than glucose, and tupelo honey tends to have more fructose than other types of honey. But does this make that honey safe for people with diabetes? Doubtful, as it's still an added sweetener that becomes glucose in a body that is not handling glucose well. A study in the August 2006 issue of the Journal of the American Dietetic Association reported that different kinds of honey with varying amounts of fructose and glucose do not differ significantly in their impact on blood sugar.
Adjustments can be made for using a small amount of honey as a minor ingredient in a mixed meal. But simple sugars such as honey, whether tupelo or a different type, will impact blood sugar level -- even more so if consumed on an empty stomach. If you have specific questions about your particular situation, it will pay to consult with a registered dietitian.
DEAR DR. BLONZ: When I checked, 1 cup of baked potatoes (150 grams, or about 3.5 ounces) contains about 20 milligrams of vitamin C. You, along with other nutrition experts, have mentioned that heat can destroy vitamin C, and baking involves significant amounts of heat. Is this an inconsistency? Are cooked potatoes still a good source of vitamin C? -- J.V., Salt Lake City, Utah
DEAR J.V.: The high heat involved in cooking potatoes does indeed destroy some nutrients, including vitamin C and thiamin (vitamin B1). There is, however, no inconsistency here: The nutrient levels in USDA data tables account for the reduction in vitamin C from the cooking process.
DEAR DR. BLONZ: Is there any problem with having calcium and vitamin C at the same meal? I have read that they counteract each other. If that is true, it would affect my typical breakfast, which includes high-fiber cereal, fresh fruits and yogurt or kefir. This also made me wonder why they would include calcium in some orange juice products. -- S.F. Tulsa, Oklahoma
DEAR S.F.: There is no incompatibility here; these nutrients go well together. If anything, vitamin C can help keep calcium in solution and facilitate absorption; this helps to explain why calcium-fortified orange juice was developed as a nondairy source of calcium.
Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.