DEAR DR. BLONZ: What part does palmitate play when added to powdered milk? -- A.P., Sonoma, Calif.
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, or retinol palmitate. You can also see palmitate in other compounds, such as ascorbyl palmitate, which is a combination of palmitic acid and vitamin C (ascorbic acid). 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 small amount of vitamin A added to the product.
DEAR DR. BLONZ: Do you have any preference of dietary supplement forms -- for instance, capsules vs. tablets? For someone getting up in years, can the body absorb one form better than the other? -- R.R., San Diego, Calif.
DEAR R.R.: It really 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 always pose questions to a company you are considering, asking them to provide data on these issues. Such information should be readily available.
DEAR DR. BLONZ: I have some questions relating to sweeteners. I read that fructose is sweeter than sucrose, and 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? -- K.E., Walnut Creek, Calif.
DEAR K.E.: There are definite differences in the level of perceived sweetness between the various 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 relative sweetness of 1.7, which means it is 70 percent sweeter than sucrose. When compared to sucrose, less fructose would be needed to achieve the equivalent level of sweetness. This highlights one of the health 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 relative 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 relative sweetness of 1.3, or 30 percent greater than sucrose.
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