DEAR DR. BLONZ: What do you know about coral calcium? I was at a lecture where the speaker attributed anti-cancer properties to this so-called “unique” form of calcium. I just sat and shook my head, but was never given an opportunity to question the claims. I remain very suspicious, but wanted to ask you if there is any substance there. -- C.B. Seattle

DEAR C.B.: Coral calcium might be considered “unique” in that it comes from the structural matrix of ocean coral, but there is no evidence that it provides anything more significant or miraculous than “regular” calcium, an essential mineral nutrient.

The origins of coral calcium as a dietary supplement include an association with the long life of the people on the island of Okinawa. There have been unscientific statements about how these people’s intake of coral calcium has prevented or cured a veritable laundry list of diseases. There is also talk of coral calcium neutralizing toxic materials, and bringing the body into balance due to its alkaline (as opposed to acidic) nature. These statements are all sales pitch, and no evidence. A case brought by the Federal Trade Commission reflects these issues (tinyurl.com/m4t8d2y), but the products continue to be sold and the nonsense lives on.

Coral calcium is a type of calcium carbonate, the most common form of calcium supplements. And guess what? All forms of calcium carbonate are already alkaline. This is why it’s a common ingredient in many antacids. There is nothing special about the alkaline properties of coral calcium. As for the ability to “neutralize toxins” and cure or prevent disease, again, there is no evidence of efficacy.

As with all essential minerals, we need calcium. No surprise there. But there’s nothing miraculous about this particular type. You were right to be skeptical.

DEAR DR. BLONZ: What are the best food sources for niacin, thiamin and riboflavin, and what do these nutrients do? -- D.F., Charlotte, North Carolina

DEAR D.F.: All three of these B-vitamins are essential nutrients, ones that must be provided by the diet, as the body cannot produce them in sufficient quantities by itself. They are all involved in facilitating the release of energy, i.e., calories, stored in proteins, fats and carbohydrates.

Thiamin, also known as vitamin B1, is also required for normal functioning of the heart and nervous system. Food sources of thiamin include animal products (eggs, poultry, fish, meats and organ foods), whole grains, legumes, nuts, potatoes, and any food fortified with this vitamin. Niacin, also known as vitamin B3, is also required for normal cell metabolism and in the synthesis of hormones and DNA. Food sources include organ meats, poultry, seafood, nuts, green vegetables and legumes.

Riboflavin, also known as vitamin B2, is important for the health of the skin, the lining of the digestive system, and the lungs. Food sources include liver, enriched milk and milk products, meats, seafood, enriched grains, asparagus, broccoli, avocados, Brussels sprouts, eggs and green leafy vegetables. For more information on these and other vitamins, see medlineplus.gov/vitamins.html.

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: If oxidation starts when air hits the cut surfaces of foods, then shouldn’t one avoid all the produce items that come cut and ready to use? Such as pre-chopped celery, carrot sticks and sliced mushrooms? -- P.M., Pima, Arizona

DEAR P.M.: Consumers are demanding more fresh, natural and convenient foods, but it is important to consider that fresh fruits and vegetables are living tissues that continue to “breathe” and metabolize after harvest. While this does not imply a need to avoid ready-cut produce, we should have some basic understanding of the process so that we can be smart shoppers.

Plant cells contain many enzymes, some of which are tucked away in special locations in the cell, walled off from the rest of the cellular contents. They remain there “on assignment,” so to speak -- the plant relies on these enzymes to metabolize (break down) what gets brought in. The products of these enzymatic actions get released for use by the rest of the cells, and the plant in general. The housing of powerful breakdown enzymes in special sub-cellular locations keeps them from acting on the plant’s vital components.

When a plant food is sliced or peeled, or if the plant has aged and dehydrated, there can be a break in the protective subcellular membranes insulating the cellular contents from their own breakdown enzymes. The liberated enzymes can begin to act and initiate breakdown on whatever cellular contents they come in contact with. This causes an apple or banana to brown when cut or peeled.

Oxidation is another way that foods can break down, this often coming from a reaction with oxygen. Cutting or slicing does expose cut surfaces to air and oxygen, but the effects can vary according to the type of food and the way in which the food is cut, packaged and stored.

There can be slight changes in quality and nutrient losses, but these tend to be minor. Vegetables and fruits tend to contain their own antioxidants that can help stave off damage. It will be obvious if the damage is significant, as the food will be unattractive and unpalatable. Color and flavor components are vulnerable to the attacks.

Companies that make use of minimal types of processing often rely on low temperatures, special washes and oxygen-scavenging systems to slow breakdown. There is even “active packaging” and controlled atmospheres that can safely maintain product freshness.

Ready-to-eat products tend to be more expensive, but in exchange, you should get a wholesome, convenient food. Be sure to observe freshness dating, and let your eyes and nose be your guides to assure you are getting the best product.

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 have questions about surimi. I’m reading that it is a white fish that’s been washed and ground until it becomes gelatin in nature. Then it gets processed with artificial colors and flavors to resemble shellfish, most commonly crabmeat. Does this mean that the surimi used in ceviche and sushi would be raw like the fish it replaces? Should I be concerned about this? -- F.F., San Jose, California

DEAR F.F.: Surimi -- the literal meaning in Japanese being “ground meat” -- is a generic name for a type of processed seafood that was first developed in Japan, but is now widely available. Surimi is made up of less-expensive varieties of fish, such as Pacific whiting, hake and pollock, that get deboned, rinsed and minced until they’re nothing more than a bland and colorless mass. The surimi is then formed, flavored, cooked and colored to resemble more expensive fish varieties, such as crab, lobster, scallops, shrimp and even lox.

Novel processing techniques are used to put the finishing touches on surimi. In one interesting method, surimi is extruded in filaments that are then woven and glued together to resemble the texture and appearance of crabmeat muscle fibers. Amidst a salad with many ingredients, a surimi-based seafood can be difficult to distinguish from the genuine article. Because of this, shoppers should always check labels, or ask the deli attendant to verify that they’re getting the expected product.

Surimi differs from fish in that it contains a number of ingredients such as sugar, carbohydrate-based binding agents, and flavorings (which may or may not include glutamate). Surimi is low in fat like standard shellfish; however, the sodium level can be higher, and because of the added carbohydrates, surimi contains about one-third less protein.

Whatever its form, surimi is already fully cooked and ready to eat, so enjoy ceviche or sushi with no concerns in that regard. Assuming the final product has been kept under proper refrigeration, any risk of food poisoning from surimi is minimal.

DEAR DR. BLONZ: I sort my dietary supplements into multicompartment containers with snapping lids, using one compartment each day, so that I don’t have to mess with all the bottles. Is there a problem keeping them together like this? What about storage in the refrigerator? -- P.T., Phoenix

DEAR P.T.: Moisture and heat can decrease the shelf life of supplements. It is best to store supplements in a cool, dry place, avoiding extreme temperatures. Most bottles contain a moisture-absorbing packet to help preserve the product; perhaps you can distribute them into the daily containers. The bottom line, though, is that if you are dealing with short-term storage in a well-sealed container, there is little to be concerned about.

Storing in the refrigerator is usually not necessary, and raises the risk of exposure to moisture through condensation. Keep in mind that there may be specific products where storage in the refrigerator (or freezer) is recommended. Be sure to read each label for specific directions.

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.