DEAR DR. BLONZ: Our daughter has eaten mostly vegetarian throughout her teens. She is not a vegan -- she eats seafood and dairy -- and she has been happy and healthy with her diet. Now comes an ideal opportunity to study in Chile, a country not known for its vegetarian proclivities. She will live and work in a rural area, and will need to conform to the normal dietary patterns of her host family.

Is there a "best" way to reintroduce meats such as chicken, beef and pork into a body that hasn't been exposed to them in years? We are concerned that initially she will be unable to digest this food, and it may leave her feeling quite sick. We'd like her to adjust her diet before she leaves home. Do you have any idea how long we should allow for her system to readjust to meat? Should we supplement her diet with protease enzymes? If so, for how long? Is there any possibility that her genes for producing proteases are permanently turned off?

Our daughter is quite enthusiastic about this opportunity and will do whatever it takes. We've got a few months until she leaves, and are most anxious for her transition to be as comfortable as possible. Any advice you can give us would be most appreciated. -- S.T., Seattle

DEAR S.T.: You need to give the human body a bit more credit. I do not believe that your daughter will have much difficulty making the transition -- at least not from a physiological standpoint. If she has been consuming fish and dairy products, or any food containing protein, she has already been using the relevant digestive "machinery." This includes the acid environment in the stomach and the protein-digesting enzymes needed for meats. There is no basis to believe that enzyme supplements would provide any advantage. She may get exposed to some novel fruits, vegetables, spices and herbs, and caution may be needed with public water in some areas, but it is unlikely that your daughter will have much difficulty digesting the meat in her diet, or that it will make her sick.

Chileans do eat meat, but there is a great variety of foods to sample. The basic Chilean diet focuses on bread, beans, potatoes and meat, but there is a long coastline and fish are plentiful in many cities. There are many soups and stews that combine corn, meat or chicken, and a variety of vegetables. Much will depend on the family your daughter lives with, but it is very likely that they will be interested in helping her feel at home.

Your daughter's attitude seems totally appropriate and on target. You could always slowly reintroduce meat as a condiment, say as a part of a sauce, to help her out. Then, over time, gradually have more meat-centered meals. Have her chew her food thoroughly and drink appropriate fluids. I expect her time in Chile will be a positive and enriching experience that will last a lifetime.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 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.

DEAR DR. BLONZ: Omega-3 fats are touted when naturally present, and are now being promoted when added to other foods. Are all omega-3s the same? In terms for a non-science major, please explain what the "omega" represents and why these fats are being promoted. -- J.S., Phoenix

DEAR J.S.: To explain the meaning of the "omega," we will need to consider a bit of structure. I will do my best to make it digestible.

First, we need to consider that fats and oils are similar in structure, the main difference being that fats are solid at room temperature (around 68 to 72 degrees F), while oils are liquid. For simplification, I will use the term "fat" for both. Think of fats as long chains of carbon atoms. In addition to being bound to each other, carbon atoms along the chain can have up to a pair of hydrogen atoms (though there are different rules for the carbons at the chain's end). If all the carbons in the chain have a pair of hydrogens, the fat is said to be "saturated," i.e., saturated with hydrogens.

When hydrogens are missing, adjacent carbons form a double bond. When this happens, the fatty acid is "unsaturated." When there is one double bond between adjacent carbons, the fat is "monounsaturated." Olive oil is an example of a food fat that's rich in monounsaturates. (Check tinyurl.com/zzbxdpz for a picture of a saturated and monounsaturated fatty acid.) When there is more than one double bond, the fat is "polyunsaturated." (On a side note, you may now better understand the terms "hydrogenation" and "partial hydrogenation," as these refer to the adding of hydrogens to unsaturated fats to change their performance characteristics.)

The term "omega" is used to signify the location on the carbon chain where the first double bond occurs. An omega-3 fatty acid is an unsaturated fat where the first double bond involves the third carbon atom from the end of the chain.

The significance is that our body requires omega-3 fats, but cannot make them on its own. We also require omega-6 fats, where the first double bond is on carbon number 6. Both types are considered "essential fatty acids," so we need to get them from our diet.

Linoleic acid is an omega-6 fat found in vegetable oils such as corn, safflower, soy and sesame, and it is also found in many nuts and seeds. Fish oils contain EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), both omega-3 fatty acids. Other omega-3s can be found in flaxseed, canola, soy and walnuts, but the EPA and DHA from fish are based on longer chains of carbons, which gives them unique characteristics. The body can make the longer omega-3 fats from the shorter ones, but it does not do it efficiently. This is why fish consumption is often promoted as an important part of a healthful diet.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 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.

DEAR DR. BLONZ: I am asking you to weigh in on a discussion at my workplace. Assuming that a well-balanced breakfast isn't an option, would it be better to have a pastry for breakfast or no breakfast at all? -- S.Q., San Francisco

DEAR S.Q.: Your question presents a choice between two undesirables. I favor having breakfast over nothing, but feel the need to improve your eating options. Granted, some people do not eat breakfast, opting instead for some variation of "coffee and" for a morning meal. Regardless of whether this is due to preference, habit, poor time-management or a combination, the fact is that the body hasn't received essential nutrients since the previous day.

We depend on food for energy, but our choices need to provide the essential vitamins, minerals and other phytochemical substances that contribute to our health. Many nutrients do not hang around for long periods, which is why it's important to eat healthful foods periodically throughout the day. Research has demonstrated how breakfast can encourage alertness, enhance mental performance, and help stabilize our blood-sugar level throughout the day. Sure, your body can adapt to a lack of morning sustenance, but don't assume that that's you at your best.

A pastry breakfast would not be a problem if it were an occasional event. The nature of the "pastry" could also be a factor. I say this because I find it difficult to give any sort of thumbs-up to a breakfast consisting solely of sweetened bread that was deep-fried, then frosted with sugary goop. While the addition of caffeinated coffee will provide temporary stimulation, it is somewhat deceiving in that it shifts the nutrient burden to the next meal. Better to replace your pastry with a muffin, perhaps made with a modicum of whole grains and containing dried fruit. Another option would be a handful of nuts, seeds and dried fruit. Add fresh fruit, such as a handful of berries, or a glass of juice and/or some sort of milk, and you now have a variety of nutrients to start the day.

DEAR DR. BLONZ: A recent column on allergies and shellfish was in need of some minor correction. "Shellfish" is something of a "basket term" -- mostly to differentiate the critters from the ocean (that we eat) that don't have fins and scales from "them's that does." They're not a family, at least not in the phylogenetic/taxonomic sense.

Clams, oysters and scallops (not to mention limpets, barnacles, octopi, cuttlefish and squid) are phylum Mollusca, while crabs, lobsters and shrimp are phylum Arthropoda. Family is designated further down, so to speak. These two phyla could not be more dissimilar in most ways, except for the fact they both live in the ocean!

Allergies to one set do not necessarily imply allergies to the other -- and possibly not even to other members of the phyla. It may be possible to be allergic to clams, for instance, but not to octopus or squid (calamari). Just thought I'd clear that up, since I learned about taxonomy at an early age from the late, great Leonard J. Waxdeck of Piedmont (California) High School, one of the finest marine biology teachers ever! -- K.H., San Rafael, California

DEAR K.H.: Thanks for this information. And isn't it wonderful to recall the impact of those special teachers in our lives?

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 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.