DEAR DR. BLONZ: I read that fructose is sweeter than sucrose, so fewer grams of fructose would be needed to achieve an equivalent sweet taste. Is this the case? What is the difference between sugar, invert sugar and honey?
DEAR K.E.: There are differences in the level of perceived sweetness between sweet-tasting substances. Sucrose, or table sugar, is a double sugar made up of glucose linked to fructose. It is used as the sweetness standard, being assigned the value 1.0. Fructose, also called fruit sugar, has a sweetness of 1.7, which means it is 70 percent sweeter than sucrose. When compared with sucrose, less fructose would be needed to achieve an equivalent level of sweetness. This highlights one of the advantages of eating fresh fruits: You get more sweetness per calorie, plus all the other nutrients found in the fruit. Glucose by itself is less sweet than sucrose, having a sweetness of 0.7. Invert sugar, honey and sucrose are similar in that they are all made up of glucose and fructose. The difference is that with invert sugar and honey, the glucose and fructose are not linked. This affects the degree of sweetness, with invert sugar and honey having a sweetness of 1.3, or 30 percent greater than sucrose.
DEAR DR. BLONZ: What part does palmitate play when added to powdered milk?
DEAR A.P.: Palmitate is a salt of palmitic acid, a saturated fatty acid. It is found in a number of foods, but its name comes from the fact that it comprises about 45 percent of the fats found in palm oil. Palmitic acid becomes "palmitate" when combined with other compounds. In milk, the vitamin A, or retinol, is combined with palmitic acid and the resulting compound can be called vitamin A palmitate. In the human body, palmitic acid makes up about 25 percent of the fats found in breast milk. It's also present in lung surfactant, a substance that coats the insides of our lung surfaces and allows us to breathe. The amount of palmitate added to powdered milk is negligible. It is only there as an escort for the added vitamin A.
DEAR DR. BLONZ: Do you have any preference of dietary supplement forms? For someone getting up in years, can the body absorb one form better than another?
DEAR R.R.: It comes down to a matter of personal preference. There are good powdered supplements, as well as products that are in capsule and tablet form. With few exceptions, taking supplements at mealtime makes sense. The mixing that goes on during digestion should give either form sufficient opportunity to dissolve and be absorbed. I have heard that some people don't "trust" tablets because they feel they will pass through without dissolving, but companies formulate their products to dissolve. You can pose questions to a company you are considering, asking them to provide data on these issues. Information should be available.
Kensington resident Ed Blonz has a Ph.D. in nutrition from UC Davis. Email him at email@example.com.