DEAR DR. BLONZ: You have written about high-fructose corn syrup (HFCS), which many of my purist friends consider to be the equivalent of dietary poison. Are they correct in this view? I have read elsewhere that some commercial use of HFCS was originally motivated by the cost/sweetness ratio of the product, particularly with the tariff on imported sucrose and its effect on U.S. sugar prices.

I appreciate your reminders about the beneficial effects of striving for balance in our food consumption; they are refreshing and well-stated. -- F.S., Lafayette, California

DEAR F.S.: The sugar/carb/corn syrup issue can best be appreciated through an understanding that the body gets off-course when overloaded with sweets. When added fructose -- not the sugar naturally present in fresh fruit -- is a major player in any too-sweet diet, a number of unhealthful biochemical shifts tend to occur.

A review article in the American Journal of Clinical Nutrition looked at the potential role of sugar (fructose) in the epidemics of hypertension, obesity, diabetes, kidney disease and cardiovascular disease. The paper suggested that high intakes of fructose are likely to be playing a role, and that certain groups, such as African Americans, are particularly susceptible. The paper correctly points out, however, that there are also illnesses associated with excessive sodium from salt, and with excessive protein.

The issue is not so much that people should reject and run away from any and all sources of HFCS. Bypassing HFCS in favor of an artificial sweetener is not the answer. My read of the evidence is that the way to get ahead of the game is to cast off as many sweetened, processed foods as possible, and stick with the real.

DEAR DR. BLONZ: I am allergic to sulfa antibiotics. Is the sulfur compound produced when eating asparagus also harmful? Should I stop eating it? Which other, if any, vegetables contain compounds of sulfur? -- N.H., Fremont, California

DEAR N.H.: Sulfur is an essential element; sulfa drugs, also called sulfonamides, are particular sulfur-containing compounds. These are not the same as the sulfur naturally found in foods. Methionine, for example, is an essential amino acid that contains sulfur, and is in all complete proteins, as well as nuts, seeds, beans and grains.

DEAR DR. BLONZ: I have a question about mixing fats. I sometimes mix a small quantity of unsaturated fat, such as canola or a mixed-blend oil, with butter when I bake cookies, piecrusts, etc. Would I be inadvertently getting a trans fat result in this simple home blend? -- M.H., San Diego

DEAR M.H.: What you are doing does not present a problem. Trans fats are formed through a multistage, timed industrial process involving high pressure and specialized catalysts. It would be impossible to duplicate this in the kitchen.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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: How do imitation crab meats compare with regular crab in terms of omega-3 fats? I asked my local fish store and was told that imitation crab comes from pollock, and I heard this is a low-mercury fish. I don’t buy it to pretend that it is crab; I buy it because it’s the only way that I can find pollock locally. And it is generally inexpensive, so that makes it a good buy. But does the processing of the pollock -- including the coloring and the flavor infusion -- change any of the omega-3 levels? -- F.M., Tulsa, Oklahoma

DEAR F.M.: While a good source of protein, and low in mercury, pollock is considered a moderate to low source of omega-3 fats -- comparable, actually, to that found in crab. A 3-ounce serving of Dungeness crab contains 383 milligrams of omega-3 fats, while a similar serving of Alaskan pollock contains 418 milligrams. For comparison with other fish, this is about one-fourth the level found in wild salmon.

While pollock isn’t particularly high in omega-3s to begin with, turning it into imitation shellfish (also called surimi) will reduce the levels even further. To make the fish look and taste like crab or lobster, they are typically deboned, rinsed, minced, flavored, colored and reformed to resemble the muscle fiber and taste impression of the desired variety. It is not a process that’s kind to omega-3 fats. A 3-ounce serving of surimi made from pollock will contain only 26 milligrams of omega-3 fatty acids.

DEAR DR. BLONZ: What are the nutritional consequences of discarding the liquid that separates from yogurt in the container? Since discovering Greek yogurt on my trip to Greece last year, I find I prefer the thicker consistency. However, I like to achieve this by purchasing American yogurt, allowing it to settle and then removing the liquid. However, I’m unsure whether I am losing valuable nutrients with this practice. -- A.A., Denver

DEAR A.A.: The liquid on top is mostly water, but also contains whey. Whey contains a bit of protein, some carbohydrates and a few water-soluble nutrients, including calcium, that remain in solution.

The texture of Greek-style yogurt comes from being strained to eliminate extra liquid. More liquid gets removed with Greek yogurt than from pouring out the liquid from a standard type; this explains why, even if you pour off the liquid and spoon out a serving, you will find some water there the next time you open up the container. Greek-style yogurt has less calcium, but a higher proportion of protein per weight.

But all things considered, when compared with the overall healthfulness of yogurt, the nutritional consequences of going Greek or pouring off the liquid from a standard type is not significant. Go with the type that best pleases your palate. Another yogurt plus is that it’s often better tolerated than milk by those with lactose intolerance. This is explained by the fact that active yogurt bacteria produce a lactose-digesting enzyme.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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 very concerned: My recent wellness check revealed that my total cholesterol was 242. I’m a 37-year-old, 150-pound white male. My triglyceride level is 71, HDL is 88, LDL is 110 and my fasting glucose is 90. There is no history of heart disease in my family. I am an avid athlete, landscaper and marathon runner, and am even sponsored by a shoe company, having had some success in races. I have been doing daily runs at an intense level for over a decade.

Food-wise, I eat a balanced diet, and rarely eat meat and animal products. I’d like to know what you think is going on, and get your suggestions for lowering my numbers. -- J.F., Boston

DEAR J.F.: You describe great habits, and you eat well. I can’t offer medical advice, but if these numbers do not jibe with previous data, you can always ask your doctor for a retest. Numbers can vary from test to test, and from lab to lab.

Your HDL is in great shape, and your triglyceride number is also in the low-risk range. There are some doctors, however, who care only about your LDL value. It’s important to discuss this with your physician. Other tests, such as C-reactive protein (for heart disease risk) and hemoglobin A-1C (for blood sugar) can provide more information, if needed. In addition, there are many websites providing information about blood cholesterol. Check out Medline from the U.S. National Library of Medicine (medlineplus.gov, search “cholesterol”).

Regarding your exercise habits, it is not always in our best interests to push “intense” on a daily basis. Have you ever considered working with a trainer? Doing the same intense workout every day can overwork the body, and landscaping work demands that your joints remain in good shape. There might be some benefit to alternating your workouts, such as running every other day and doing complementary exercises, such as yoga, tai chi or resistance training, on the alternate days.

An unfortunate fact of life is that the body becomes less forgiving as we transition to midlife. Our habits determine when midlife begins and how long it lasts. It is likely that you have already gotten subtle reminders that youthful flexibility doesn’t last forever, even for one who maintains an active lifestyle. Even those who stay active need to refine their workouts as the years go by. This is not a bad thing, and by doing so, you can remain injury-free and at the top of your game. Let me know how things turn out.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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.