DEAR DR. BLONZ: In an interview, a well-known doctor (and author of several books) said that fructose was a "demon" to be avoided because it causes glucose to be created and leads to insulin resistance. He said that the consumption of fruits should be limited, since they are a big source of fructose. Hearing this was a bit strange given that fruits -- along with vegetables and other plant-based foods -- are the main parts of my diet.
Why would a noted physician say such things? I thought the interviewer was too accommodating and did not ask any challenging follow-up questions. I am in my middle years, and I have developed daily workout routines and walks to keep off the excess pounds. I am interested in what you have to say about fructose. -- S.P., New York City
DEAR S.P.: In recent years, there has been more fact-checking of political presentations and statements. But in the health and nutrition arena, information ranging from the dependable to the dubious still flows freely -- with the consumer left in charge of telling the difference.
Cautions against the excessive intake of sweeteners containing fructose make sense; these include sucrose (table sugar), high-fructose corn syrup, invert sugar and honey. The essential word, however, is "excessive," as valid arguments should not be aimed at fructose in general.
To explain, insulin is our "I am fed" hormone; it gets released from the pancreas in response to rising glucose in the bloodstream, which is typically an indication of a recent meal. Once the blood glucose level drops to its normal range, the release of insulin also drops. (Having sweets on an empty stomach is a risky routine because it sends an unhealthful curveball to this system.)
Habitually taking in too much sugar, including fructose, can contribute to insulin resistance, which is a condition where the body becomes less responsive to insulin, forcing the pancreas to produce more. Overweight individuals are at higher risk for developing insulin resistance. The condition is associated with several health problems, including Type 2 diabetes. (Read more at b.link/6yddqk.)
Excess fructose can be more harmful than excess glucose in that the fructose structure allows it to bypass the controls in place for glucose. That excess encourages the production of triglycerides, which can build up in the liver and raise the risk of "fatty liver" -- a condition associated with the excessive consumption of fructose and other sweets.
There is, however, no basis (or evidence) to malign fructose when not consumed in excess, especially when it is the fructose naturally present in fruits. Fructose tastes sweeter than glucose and is about 1.5 times sweeter than table sugar (sucrose), and this means fewer grams of fructose are needed to achieve comparable levels of sweetness.
My compliments for your efforts to avoid excess weight. The process of gaining weight can overwork the pancreas until it simply can't keep up, resulting in diabetes. Between 80% and 90% of adults with Type 2 diabetes are overweight. This also helps explain why many with the condition can experience improvements when they become more physically active, lose a few excess pounds and shift to a plant-based, whole-food diet that -- yes -- includes fruit.
Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to firstname.lastname@example.org. Due to the volume of mail, personal replies cannot be provided.