DEAR DR. BLONZ: As an Oakland, California, resident, I appreciate each of your columns in the East Bay Times. The recent column on protein was timely, as I am a 71-year-old, just over a hip replacement, and working via lifting, cycling, and yoga to gain and maintain muscle mass. In your response to a recent question about protein, you stated that "active individuals may benefit from up to ... 27 grams of protein for every 30 pounds of weight." By my calculations, as a lean 153-pound male, that equates to about 135 grams of protein per day. That amount seems very high and unreachable for anyone other than a professional bodybuilder. Is your recommended grams per 30 pounds a misprint or miscalculation? I would appreciate a response so I can target my nutrition on a daily basis. -- D.P., Oakland, California

DEAR D.P.: Thanks for your kind comments. No recalculation is needed for that level, which was described as being for "athletes and intensively active individuals." That would characterize competitive weightlifting/powerlifting, Ironman, long-distance cycling, and military basic training types of workouts -- things that would be done five to six days a week. The food/calorie intake is high at that level of physical demand; the need for protein is up as well. You will have to decide where you fit with your routines, but please understand that excess dietary protein, i.e., more than the body needs, is not a health asset.

Having recently undergone a total knee replacement and relying on physical therapy, with a 3x weekly workout and steam at the Y, I am now back with a much better knee! I continue to eat well, but I did not see the need for extra protein during that process. I wish you the best with your recovery.

DEAR DR. BLONZ: In a recent column on protein, you failed to address an important side element in the question. The writer mentioned that the gym offered collagen protein drinks for building muscles. Collagen protein is not ideal for muscle building due to its amino acid content, specifically that it is low in leucine, an essential amino acid, compared to the levels in milk/whey protein. -- D., El Cerrito, California

DEAR D.: You raise a valid point, but it would not be an issue unless collagen was a primary protein in the diet. If one is already getting their requirement for high-quality (complete) protein, the difference between a collagen drink and a different type, such as whey, or a vegetarian source, would make little difference.

That element might have added unnecessary complexity to the main issue involving the value of extra protein. There is some research on the value of added collagen for connective tissue, but most of these studies involve individuals with marginal protein intakes. You are correct that whey, which comes from dairy, would be a preferred source when supplementary protein is needed, but there are attractive vegetarian sources as well. Consider checking the essential amino acid contents of any product you are considering.

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: This is about a solution to the stomach problems that were experienced by my daughter. We were not sure whether it was some medical condition, stress, or even a food allergy. At a periodic wellness visit with our family physician, many questions were asked, including whether she had gum and sugar-free mints. I remember you had written about this, and that she always chews sugarless gum, but I never made the connection. This turned out to be the answer. I wanted to pass along that since she stopped, her stomach problems have disappeared. -- S.A., Martinez, California

DEAR S.A.: My hat's off to the family doctor and to your family for having periodic wellness visits. The sweeteners most commonly used in sugarless gums and mints are xylitol, mannitol and sorbitol, all members of the sugar alcohol family. Even though they are indeed carbohydrates considered to be sugars, they merit the "sugarless" label because, despite their sweet taste, they don't promote tooth decay. Sugar alcohols possess this quality because, unlike other carbohydrates, the bacteria in and around our teeth cannot metabolize them to produce the enamel-destroying acid associated with tooth decay.

One negative characteristic of sugar alcohols is that they attract water when they're in the digestive tract. Substances with this quality contribute to digestive upset that includes diarrhea and cramping. Also, sugar alcohols are not efficiently absorbed, so they tend to remain in the digestive tract and reach the large intestine. There, they serve as food for our microbiome, many of which produce intestinal gas as a byproduct.

The symptoms are mild when small amounts are consumed, or if they are eaten with or soon after a meal. If, however, larger quantities are consumed, such as several mints or sticks of sugarless gum, and if they are eaten on an empty stomach, the result can be the type of upset your daughter experienced. Read more about sugar alcohols and how they are shown on food labels at b.link/e7gfcew.

DEAR DR. BLONZ: I wanted to say thanks for an earlier column in which you covered positive benefits from chocolate. My question is whether the antioxidants you described are in the cocoa powder or in the cocoa fat. If it is in the fat, would that mean that the only way to get the benefits is to have full-fat chocolate? -- D.M., Benicia, California

DEAR D.M.: Research on chocolate has indeed identified the presence of beneficial compounds. These compounds, known as flavonoids, are found in the cocoa solids, not the cocoa butter. This means that they are in the cocoa powder, and, of course, in the whole chocolate confection. Dark chocolate, which has more cocoa solids, tends to contain more flavonoids than milk chocolate, and white chocolate (no cocoa solids) contains very few flavonoids, if any.

As for whether having cocoa powder is a "better" way of getting the benefits of the chocolate, that, I think, is a matter of personal preference. There are plenty of foods with wonderful attributes. Eat chocolate because you enjoy it, not because you think it's good for your health.

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: We had great-tasting grilled frozen swordfish steaks at a friend’s place, prepared according to the package instructions. I would appreciate your comment on whether this is a good fish to have, given concerns about mercury content. My main question comes from my learning that the leftovers had inadvertently been left in a sealed container on the counter overnight, rather than being put in the freezer as planned. My friend told me she put them in the freezer the next morning. I questioned the wisdom of this, and she told me that the original grilling would have killed the existing bacteria on the uncooked fish, and that freezing (even if begun the next morning?) would kill any bacteria that might have grown during the night. Then, when it came time to have the leftovers, reheating would finish the job. I questioned this, and she said it was a common practice, and no one had ever gotten sick. Is this a safe? Does freezing kill bacteria? Not to mention what it might taste like, and the general safety of swordfish.

-- W.N., Portland, Oregon

DEAR W.N.: You certainly are a good friend, and I hope you will pass this reply to your neighbor before they consider having those leftovers. Freezing would not kill bacteria in this situation; all that freezing does is to suspend the growth of microorganisms. It is essential to realize that freezing does not make food fresher than it was before it was frozen. Whenever a food is defrosted, bacterial growth resumes exactly where it left off. Eating foods left out on the counter is an unnecessary roll of the food-safety dice. There could be no guarantee of safety, even after reheating the next day. The idea of them being in a sealed container on the counter provides no reassurance, as cooling foods can draw the bacterial wild card of external air into the container while the food is temperature-sensitive. In my considered opinion, the best course of action would be to discard the items.

As for the healthfulness of eating swordfish, it provides an excellent source of protein, vitamins D and E, most of the B vitamins, along with omega-3 fatty acids. There are, however, real concerns about its mercury content. Fish are the main dietary source of this toxin for humans. As healthful as fish can be, estimates in the scientific literature are that about 90% of the mercury in our bodies comes from fish, typically from varieties high up on the marine food chain. The most commonly consumed higher-mercury fish include swordfish, shark, orange roughy, tilefish and certain types of tuna. (Side note: Salmon is not a fish of concern in this regard.)

Mercury is distributed throughout a fish, so cleaning and the method of preparation can’t solve the problem. It’s best to have no more than one serving per month of any high-mercury fish. Pregnant women and children should be at the lower end of that range, if you get my meaning. For more on mercury in fish, see b.link/pb677p5. Low- or no-mercury fish can be consumed more frequently. Check seafoodwatch.org for fish recommendations.

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.