DEAR DR. BLONZ: Is there saturated fat in fish? My impression was that the fats in fish are highly unsaturated. -- F.S., Des Moines, Iowa

DEAR F.S.: Naturally occurring fats and oils are a mix of saturated, monounsaturated and polyunsaturated fatty acids. The type that is most prevalent in any given food is the one that generally gets associated with it. Olive oil, for example, is thought of as monounsaturated, but 10 percent of the fats in olive oil are saturated, and 13 percent are polyunsaturated. Now what about lard? The very mention makes one think "saturated," but with lard, the predominant fat (approximately 45 percent) is actually monounsaturated. Another 11 percent of the fat in lard is polyunsaturated, with 39 percent being saturated.

Fish are generally thought of as sources of polyunsaturated (often omega-3) fats, but they contain saturated and monounsaturated fatty acids as well. The percent breakdown depends on the variety. You can search the USDA database (ndb.nal.usda.gov) for the details.

DEAR DR. BLONZ: A number of people in my office rely on guarana pills for alertness and better concentration on the job. One has even said that guarana helps with impotence. What are your thoughts? -- S.E.D., Phoenix

DEAR S.E.D.: Guarana comes from the seeds of the South American shrub with the same name. The effects you mention, relating to alertness and concentration, have to do with the substance named guaranine, which is usually known by its more common name: caffeine. Yes, that's right: It's caffeine that's responsible for the pharmacologic effects of guarana. On a weight basis, there is more caffeine in guarana than there is in the coffee bean, the kola nut, mate or cacao (cocoa).

There is no standard concentration of caffeine in the guarana extracts used in dietary supplements. Read the label or check with the manufacturer to see how many milligrams of caffeine there are in a serving of any guarana-containing product. Use guarana as you would other sources of caffeine. There is no support, at least none that I could locate, regarding guarana as a "cure" or treatment for impotence.

DEAR DR. BLONZ: Is there a health difference between steel-cut oatmeal and longer-cooking oatmeal? Does the preparation make a health difference, too? I prepare mine by putting both the oatmeal and the water in at the same time and then cooking. -- O.M., San Jose, California

DEAR O.M.: There is no difference in health or nutrition composition between steel-cut and traditional long-cooking oatmeal. The same goes for quick-cook oats. It is the cut of the oats and the speed in which they cook, not the oats themselves, that are different. One half-cup (40 grams) of the dry oats in any of those cuts will contain about 3 grams of fat, 5 grams of protein, 27 grams of carbohydrate, 4 grams of fiber, and no sodium. Your method of preparation sounds fine.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 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 finally stopped smoking cigarettes, and my healer recommended a liquid diet to help my digestive system relax and expel all the toxins that have accumulated. Along with this came a heavy recommendation to get a colon cleanse, but I am reluctant. I know to expect some weight gain, and this is a concern. I think it is one of the reasons I have been unsuccessful at quitting in the past. I was hoping you might have some suggestions. -- S.F., San Diego

DEAR S.F.: As an active smoker, you were inhaling the solid refuse of burning tobacco, which was coming in faster than the body could cast it off. The body is always attempting to clean itself, and our lungs normally secrete mucus to entrap dust and other inhaled particles. The healthy lung then shuttles the mucus out through a series of cilia, or hairs.

But the entire process breaks down with burning tobacco: The smoke coming in contact with the cilia and sensitive lung tissues causes inefficiencies in this vital self-cleaning system. The more and longer you smoke, the messier things get inside. Mucus, tinged with tobacco byproducts, collects in the lungs, resulting in the typical hacking "smoker's" cough." Quitting smoking is one of the best steps toward healing you can take.

Once you stop (hooray!), the cleaning system begins to chip away at the backlog. It takes a while for the body to cleanse itself, and water serves as a main conduit for elimination. It makes sense to have plenty of healthful fluids, such as water and fruit or vegetable juices, working through your system. Forget the colon cleanse; there's no evidence that this does squat for smokers.

As for foods, people usually have an urge to eat more after quitting smoking, so you should have some foods around of low caloric density. Eat normally at mealtime, but be alert about the quality of your snacking. Good between-meal foods include fresh fruits, cut vegetables, whole-grain pretzels, and even sugar-free gums and candy. Other suggestions include rice cakes, air-popped popcorn, whole-grain dry cereals, raisins, etc. These foods can help fill you up without contributing an excess of calories.

If you have the OK from your (medical) doc, it may help to begin going on walks, or doing some other sort of exercise, such as bike riding, dancing or any other activity you enjoy. Not only will this help control any potential weight gain, it will be an important first step in telling your lungs and muscles to get in step with your new existence.

Don't give up if you gain a few pounds. Those can be lost later. The key is to get over the proverbial "hump" of about four weeks, after which the worst of the withdrawal symptoms will be history. There are many programs and support groups around that can be of help. E-cigarettes are not a solution, but they can serve as a bridge to getting nicotine dependence out of your life. The National Institutes of Health has an excellent reference website on smoking cessation: tinyurl.com/ybwl8ec.

Finally, you definitely need to spend some time giving yourself a good pat on the back. Set up a system of rewards, and if there is a (hopefully nonsmoking) significant other in your life, have that person be in charge of giving you gifts for every month that you stick with it. I congratulate you and wish you luck and determination as you continue down this road.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 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: Is there truth to the "raw foods" movement's claim that cooking kills the natural enzymes in foods, including vegetables, and that this removes the vital nature of the food and poisons our bodies? -- J.C., San Diego

DEAR J.C.: Raw foods contain enzymes that play a part in the metabolism of the plant while it is alive, and this includes the creation of the seed. Inside a viable seed, enzymes play a role in nourishing the growth of a new plant. Heat can destroy these plant enzymes, but -- and this is the key -- these enzymes are there for the plant, not for us.

The human body makes its own enzymes to digest the foods we eat. Our digestive process tends to destroy any enzymes already present in our food. They tend to be proteins in nature, and get treated like other proteins we might consume. The acidic environment of the stomach denatures the enzyme, then our own digestive enzymes begin the job of breaking them down to their amino acid parts in preparation for absorption.

Cooking can make certain foods easier to digest, and it can even make certain plant nutrients more bioavailable for our bodies. Appropriate cooking will "kill" anything that is alive in a food, but eating food prepared in this manner does not poison our body. Overcooking (excess heat) can destroy much of the nutritive value of a food -- and it can, if taken to an extreme, create mutagenic and carcinogenic substances -- but that is not what we are talking about here.

There is absolutely nothing wrong with eating fresh, wholesome plant foods that have not been cooked, but do it because you like the taste -- not because you fear that cooking creates poisons.

DEAR DR. BLONZ: I have a friend who is lactose-intolerant, and I was wondering if her allergy to milk means that she should not have butter. -- M.A., Marysville, California

DEAR M.A., Lactose intolerance is not the same as an allergy to milk. This type of intolerance occurs when the body does not produce sufficient amounts of an enzyme (lactase) to digest a naturally occurring carbohydrate (lactose) present in many dairy products. When a lactose-intolerant individual consumes more lactose than her body can handle, she can experience symptoms such as stomachache, bloating, gas or diarrhea. These individuals usually have no problem with butter as it contains little, if any, lactose.

A milk allergy occurs when there is a specific sensitivity to milk protein. This condition is one that should be confirmed through testing by an allergist. When an individual with a milk allergy eats a food that contains milk protein, he can -- depending on his level of sensitivity -- experience symptoms ranging from sneezing, runny nose, asthma, skin rashes, nausea, diarrhea, swelling, headache, or even a life-threatening drop in blood pressure. Butter will contain a small amount of protein and it, along with all other dairy products, should be considered off-limits for an individual with a milk allergy.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 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.