DEAR DR. BLONZ: If I were to take herring that is sold in a wine sauce and rinse it in water to remove the salt, does it lose any of the healthful omega-3 fatty acids? I enjoy eating herring, and want the fats, but prefer not to have the salt. -- M.M., Washington, D.C.

DEAR M.M.: Herring are a rich source of omega-3 fatty acids, and these fats will still be there after a salt-removal swim.

The level of omega-3 fats in herring is impressive: A study in an issue of the Journal of Agriculture and Food Chemistry reported that the sought-after EPA and DHA omega-3s represent more than 12 percent of the fatty acids in herring. Pacific herring were found to have slightly higher levels than those swimming in the Atlantic, but both types were higher than the level of essential omega-3s in sardines, salmon, tuna and trout. Read more about the different omega-3 fats at tinyurl.com/y9vd9mbo.

DEAR DR. BLONZ: Is it safe to put raw chicken in a slow cooker and cook it on low for eight hours or so? I am very hesitant and afraid it will be full of bad bacteria. -- S.G., San Diego

DEAR S.G.: A properly functioning slow cooker, or Crock-Pot, will cook foods between 170 and 280 degrees, which is sufficient to bake bacteria out of existence. The meat should be fully defrosted before it goes into the cooker. Fill the cooker at least halfway, but no more than two-thirds full. Cut the larger pieces of chicken into small chunks to ensure thorough cooking.

Finally, steam helps the process, so keep the lid in place. If you are going to be around, cook on high for the first hour, then lower the temperature to that called for in the recipe.

DEAR DR. BLONZ: In a recent column, you equated lactose and lactate. This is wrong! Lactose is a disaccharide. Lactate is the ionized form of lactic acid, a three-carbon organic acid. Lactic acid is a fermentation product of sugars, including lactose, and is found in sour milk, yogurt, pickles, saurkraut, etc. It is used as a preservative in many foods. It’s not going to contribute to symptoms of lactose intolerance. -- S.R., via email

DEAR S.R.: You are correct, and thanks for pointing out that error. “Lactates,” used as additives in certain foods, are completely different from lactose, the carbohydrate found in dairy products that can cause problems for lactose-intolerant individuals. Thanks for the careful read.

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: Whenever our grandchildren come to visit, they immediately launch into this game where they go through the refrigerator and all our cabinets and try to find foods that are out of date. It is something that my daughter taught them and encourages them to do. (They found us eating something out of date at one visit.) The kids check the “sell by” dates of our canned goods and dairy products and toss anything that has expired. I have found, or should I say “not found,” eggs just over the line, and was unsure whether they were still safe. Aren’t some of these items still usable for some time after the dates have passed? -- A.G., Walnut Creek, California

DEAR A.G.: The breakdown of food is a gradual process and does not take place on one particular day. The accuracy of any dating system relies on the proper handling of foods from field to plate. If there’s been any mishandling by the manufacturer, trucker, supermarket or consumer, the flavor and safety of the product can be compromised.

The presence of all these variables means that these are not precise systems; what we sense with our eyes, nose and palate should overrule any freshness dates on a product. Unfortunately, there is no one federal standard for food dating, so we have to cope with a variety of different systems on products. The various systems provide instructions for the retailer and the consumer.

“Sell by” dates are for the retailer, and represent the last date at which the product should appear on the supermarket shelf. Perishable foods such as dairy products, meats and bread use this method for freshness dating. The “sell by” date allows time for normal home use. Let your daughter and grandkids know that properly stored eggs, for example, can be good for four to six weeks after their “sell by” date.

An “expiration,” “use by,” or “do not use after” date represents the last date at which the product would be of sufficient quality to be consumed, according to the manufacturer/producer. This does not necessarily mean the item will become dangerous after that point; it represents the producers’ advisory that it might not be of the same quality as when it was made. For example, yeast or refrigerated dough products might not rise as expected if used beyond the expiration date.

If you are going to buy their foods, manufacturers want you to enjoy them so you’ll become a repeat customer. As a result, most foods contain some sort of freshness date, as this is the manufacturer’s estimate of the last date at which their product will have retained its flavor and quality. These items are marked with “best if used by,” or similar terminology. Soft drinks, for example, tend to lose flavor over time, so their freshness date tells you when they are at their best. Cereals and canned goods also use this type of dating.

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: You wrote about flax recently, and I bought some, ground it in my coffee grinder, and have been adding it to my diet on a daily basis. I have two questions and was hoping that you might be able to help. First, what is the recommended daily amount? I have found anything from 1-3 tablespoons as a guideline. I want to take enough to get the benefits, without taking too much. Secondly, and more importantly: A physician quoted online said that men should avoid flaxseed based on a study by the University of Virginia School of Medicine, which found that the oil “may promote the growth of prostate tumors in someone with prostate cancer.” Is this a valid concern? Does it apply to ground flaxseed? Is the risk worth the health benefits? -- P.P., San Jose, California

DEAR P.P.: Fats and oils represent nature’s most concentrated sources of energy. Fat is the storage material of choice in the plant world, ideal when there is a need to pack a lot of energy in a small space. Seeds tend to be light in weight and small in size, yet contain sufficient energy to fuel a plant’s initial growth until the sprout can poke out of the soil, into the sunshine, and begin to make energy on its own. Seeds need protections for this purpose. The primary defense is the seed coat, but also important are the phytochemical substances that protect the fat from various environmental, insect or microbiological elements.

Flaxseed oil is highly unsaturated: About 60 percent of the fatty acids in flax are polyunsaturates. Of concern with prostate cancer is alpha-linolenic acid (ALA), an omega-3 polyunsaturated fatty acid that is plentiful in flax. Research has reported a significant relationship between the intake of ALA and the risk of various aspects of prostate cancer.

A key point here is the fact that when flaxseed oil is removed from the seed and separated from its phytochemical bodyguards, the chances of the oil breaking down and causing health problems may increase. With whole flaxseed, you get the entire package of fats, fiber and the variety of phytochemical compounds and antioxidants, known as lignans, naturally present in flax. These are not normally present in flaxseed oil. You can, however, find flaxseed oil products that include these compounds along with the oil.

Whole flaxseed has not been associated with an increased risk of cancer. In fact, there is evidence that this whole food has cancer-fighting abilities.

The message here is that we need to make sure that the fats we eat are well protected by having them as a part of a whole food. Eating whole greens, vegetables, fruits and certain seeds allows those foods to bring along their full variety of healthful components.

When eating flaxseed, cracking or grinding the seeds makes sense, as the fibrous protective coats of intact seeds tend to pass through undigested. One tablespoon of ground flaxseed contains about 1.6 grams of omega-3 fatty acids, which is in the range recommended for adults by the Institute of Medicine. (If not used immediately, ground flax should be refrigerated in a tightly sealed container.) In the end, if you have concerns about prostate cancer or any other cancer, be sure to discuss your choices with your physician, or the dietitian with whom he or she works.

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.