DEAR DR. BLONZ: Are the natural flavors the same as what you would find in that actual food? For example, orange is one of my favorites; when a food labeled "all natural" says it is made with actual oranges but also lists "natural flavors" or "natural orange flavor" as an ingredient (I've seen both), is that referring to the oranges? -- M.R., Dover, Delaware

DEAR M.R.: Flavors come from collections of chemicals, whether made by nature or constructed in a lab. To copy the flavor from the naturally grown food for a processed food, flavor chemists identify nature's compounds at play. Precise, synthetic versions can be used to construct the desired flavor. The task, ironically, becomes more complex if the copy is to be a "natural" flavor. In that case, the compounds must come from natural sources such as fruits, vegetables, herbs, spices, meat, dairy or fermentation products, with no requirement that they come from the food whose flavor is being copied.

Why not use, or copy, the flavor substances in the actual food? While this seems preferable, it's impractical on any large scale. And, as flavors go, the natural ones are typically weaker when removed from their natural foods. Many are unstable and break down during processing, transport and storage. In addition, natural flavors may interact with other ingredients in a recipe, or even with the packaging material. There's also a question of uniformity. While fresh foods grown by nature can vary in flavor, processed foods must answer to a higher authority: the consumer. Biting into a less-sweet orange won't stop you from eating oranges, but an undesired taste in a processed food made with "natural orange flavor" might cross it off your shopping list for good. And, since opinions about taste vary, one company's version of a "natural" orange, or any other flavor, may taste nothing like another's.

Also consider that, from the plant's perspective, flavor is a short-term requirement, just long enough to get the fruit selected so its seeds can reach the soil. Energy is the most vital commodity; there is no need to invest more to keep flavors going when the energy priority is to fuel development until the plant can emerge, spread its leaves and begin getting energy from the sun on its own.

A good advertising campaign might persuade a consumer to try a product, but repeat business and ultimate success in the marketplace depend to a large extent on how it tastes. With today's demand and the level of expertise, we can no longer assume that a processed food product is more wholesome just because it uses natural flavors, or that it's inferior if the flavoring is artificial.

As for processed foods, always check the label to see what you are buying. While it may seem desirable to have "natural" or "nothing artificial" on the label, there's no automatic nutrition, taste or safety advantage that those with natural flavors hold over their synthetic counterparts. But, of course, we can avoid the flavoring issue altogether by sticking with fresh whole foods, which should be the main players in our diet.

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: Please explain more about placebos and controls and whether they can actually bring about health benefits. -- G.B., Anderson, South Carolina

DEAR G.B.: When early research results confounded expectations, scientists began to suspect that effects could occur simply because they were believed to be due -- even if no active ingredients were present in the treatment being given. (Key side note: And, yes, this may shed light on what's going on with "miraculous claim" supplement products that lack objective testing, but go heavy on product promotion. It is why potential customers should demand clinical evidence, rather than testimonials, before they buy.)

Scientists began using placebo controls in their studies to provide inactive treatments that appeared and tasted similar to the active treatments. When only the subjects do not know what treatment they are receiving, it is a "single-blind" study. However, many subjects wanted to know which group they were in, so they tried to pick up clues from anyone working on the research. Researchers often asked subjects at the end of the study whether they had learned which group they were in and how they had come to know it. When subjects have such knowledge, it thwarts the reliability of findings.

Quality researchers stepped in to design studies in which no one -- from the subjects, to those administering the treatments, to the researchers conducting the analyses -- could know who was in which group. Codes are used and are not broken until all the data has undergone final analyses. When placebos are used and nobody knows who's getting what, it's called a "double-blind, placebo-controlled" study, a premier method in clinical research.

An interesting side story was when an important concept was discovered using control treatments. In one study, grapefruit was used to mask the taste of a drug being tested so that subjects could not discern between the active treatment and the placebo. In this study, they found unusual results in the placebo group, revealing the profound impact grapefruit can have on drug absorption and metabolism. This finding led to our understanding and caution about the "grapefruit effect" with certain medications (see b.link/8mqcd for more).

DEAR DR. BLONZ: Is there any basis to the advice that the body shouldn't have fruits and vegetables at the same meal? Is this nothing more than a widely circulated, long-standing myth? If so, it dies hard. Thank you. -- A.S., Raleigh, North Carolina

DEAR A.S.: There is no one way of eating that works for everyone. We all have our quirks and preferences, food-prep abilities, social circumstances and takes on the physiological rules of the day. If there were to be a generalization in this matter, though, it would be that there is no evidence that fruits and vegetables have to be consumed separately.

Our digestive system is well-designed for mixed meals, having specific areas for the sequential breakdown, processing and absorption of the food's nutrients. The "die hard" aspect relates to period romances with misinformation from folklore that preceded evidence and our understanding of how things work in the body. For a more detailed view of our digestive system, see b.link/vq7rpkz.

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: 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.