DEAR DR. BLONZ: Could you tell me if roasted or raw would make any difference with nuts, health-wise? What about the difference between oil roasting and dry roasting? One proponent of raw peanuts states that one half-cup of raw peanuts has 430 calories, but processed into peanut butter, a half-cup contains 780 calories. How can this be? -- S.S., Malibu, Calif.
DEAR S.S.: You are mixing volume with weight. There is space between those peanuts in the half-cup, which weighs about 73 grams. Contrast this with a half-cup of peanut butter, which weights 129 grams. If you were to look at similar weights of these two foods, the caloric content would be comparable.
When you roast nuts, or any food for that matter, it can bring about flavor-enhancing chemical reactions. With nuts, this can be accomplished with or without oil. Dry roasting requires specially designed ovens and utilizes hot air. Salt, paprika or other flavorings can then be added if desired.
Although dry-roasted nuts contain no added oils, there will only be a nominal difference in overall fat content as compared to oil-roasted nuts. This is because half the weight of the nut, and over 70 percent of its calories, come from its fat content. A honey-roasted nut will contain less fat per serving because some of the weight is taken up by the sugary coating. In terms of nutritional value, the high heat process will destroy some of the folate and thiamin (vitamin B1), but the other nutrients are unharmed.
Raw peanuts will have a different taste from roasted ones, but a comparable fat content. One item of interest is a study in the October 2000 issue of the Journal of Allergy and Clinical Immunology, which reported that raw peanuts provoked less of an allergic response in sensitive individuals than roasted peanuts. However, as there raw peanuts carry a slightly higher risk of microbiological contamination, they are not recommended for individuals with compromised immune systems. Raw peanuts should be stored in the refrigerator. Only buy them from sources that sell a lot of them, and avoid places where the raw peanuts might have been sitting around for a long time in a bulk bin.
DEAR DR. BLONZ: Can you explain why the vitamins and minerals in a dietary supplement expire? What is the best way to store these products? -- S.H., Arlington Heights, Ill.
DEAR S.H.: Vitamins are reactive compounds that play an integral role in the chemical reactions that comprise our metabolism. Although mineral supplements tend to be quite stable, vitamins can slowly lose their potency over time. The factors that encourage breakdown are humidity, temperature and light. Formulas that contain fat-soluble nutrients tend to break down the fastest. The best way to store products is in a tightly sealed container in a cool, dark place. Many supplements include moisture-absorbing capsules or packets to help maintain product quality. Product expiration dates indicate when the vitamins can be assured of full potency -- assuming that the product has been appropriately stored.
Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to email@example.com. Due to the volume of mail, personal replies cannot be provided.