DEAR DR. BLONZ: I enjoy eating artichokes, but am skeptical of the claim I read that they can help cleanse the arteries. I would appreciate a comment about this. Also, are artichokes best if eaten raw or steamed? Is the expensive canned version just as healthy? How often should artichokes be eaten, and how much at a time? -- T.T., Walnut Creek, California

DEAR T.T.: This is a good time to be discussing artichokes, as spring is their peak season. The artichoke is in the same family as the sunflower and the thistle. The globe-shaped “vegetable” that we eat is actually the immature bud of a beautiful seven-inch purple flower. That helps explain why springtime, when flowers typically emerge, is when we see artichokes at farmers’ markets. (If you were planning to attend, the annual Artichoke Festival in Monterey, California -- where you can sample anything and everything artichoke -- has been postponed until August.) If left to bloom, the artichoke loses its appeal as a food, but the blossom can serve nicely as a table decoration.

Artichokes are not typically consumed raw, but are eaten after being steamed, boiled or baked, at which point they can be enjoyed hot or cold. Those that come canned are also excellent.

The artichoke is high in vitamin C and fiber, and is a good source of folate and magnesium. The artichoke plant contains several beneficial phytochemicals, some of which are antioxidants and others that may be of help to the liver.

One compound, cynarine, encourages the production of liver bile, which is used to emulsify ingested fats (lipids) during digestion. This plays a role in how we handle dietary cholesterol, but it’s not the same as “artery cleansing” -- no facts to back that claim. Another compound, silymarin, is a mixture of substances also found in milk thistle (an artichoke relative, as mentioned). It has been shown to have liver-protective properties, and the liver makes cholesterol when the body needs it. (Interesting side point: Even if we had no cholesterol in our diet, the liver would make all we needed.)

But it is important to understand that while the part of the artichoke that’s eaten may contain some phytochemicals, most tend to be found in the leaves of the plant. If a website mentions “evidence” to support a claim, be sure to check the source to see what part of the plant was used in the research.

How often should you eat artichokes, you ask? Let your palate be your guide. The artichoke does indeed have healthful attributes, but it is one player in what should be a grand cast of whole-food characters.

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: From the standpoint of nutrition and energy level, is it best to stick with three meals per day, or spread those same foods into smaller meals throughout the day? -- S.T., Dallas, Texas

DEAR T.X.: The overall nutrition status is not significantly different, because the same foods will be eaten. That said, several studies have shown that midmorning and midafternoon meal breaks can enhance work performance -- but the explanation may be more psychological than nutritional.

Interestingly enough, the subjects in those studies who had not eaten a nutritious breakfast showed the greatest improvement. Their typical “coffee and a quick bite” morning meal gave them a jump-start for the day, but only enough dietary energy to last a couple of hours. The caffeine effect was responsible for much of that. For them, having a midmorning break resulted in a needed energy boost.

A complete breakfast, in the studies, included a source of protein, complex carbohydrates and some fat. Those who ate that at one sitting did not report any significant change if they broke that food into two smaller meals. Multiple meals may help break up the tedium of the workday, but the nutrients absorbed by the body are comparable.

Having several meals throughout the day, often dubbed “grazing,” may have potential benefits for dieters. But grazing also has drawbacks, one of which is that it becomes more difficult to keep a handle on total food intake. Besides, when any time can be mealtime, one might be susceptible to errant snacking -- a pitfall of the unsuccessful dieter.

DEAR DR. BLONZ: As a physician, I am always questioning the description of over-the-counter drugs and herbal supplements as nothing more than “harmless placebos” if they do not work as intended.

The American Society of Anesthesiologists and other medical organizations have put out alerts and printed brochures concerning the potentially undesirable effects of these substances, and the ways they can complicate health conditions and affect other medications. When patients do not consider supplements and OTC meds as drugs, they may not mention them when asked about their drug histories. This could be serious: For example, some supplements might affect the way the blood clots, which would be especially risky during surgery. Unfortunately, the FDA and other government agencies probably don’t get much publicity to warn about such things.

Always be upfront with your health care team about all that you take. An essential ally in this is your pharmacist, as they have records of your prescribed medications. If using multiple pharmacists, be sure they are aware of all you are taking. -- R.B., Phoenix, Arizona

DEAR R.B.: Thanks much for your important note. There is no question that OTC drugs, and herbal or other dietary supplements, can raise the risk of health complications, especially during surgery. Patients need to be forthcoming about everything they are taking, and anesthesiologists and surgeons, or their nurses, need to ask the right questions prior to any procedure. In the same way, medical doctors need to inquire about such substances before writing new prescriptions. Pharmacists must also be given this information so that they have the ability to check for interactions. There are online drug-interaction sites, including drugs.com and rxlist.com, where you can enter all the things you are taking or considering, and see whether there are issues to consider.

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 am hoping to learn more about the history of chemicals used as food additives. With the advent of controlled atmospheres to limit spoilage, why are additives even needed? -- S.L., Tulsa, Oklahoma

DEAR S.L.: There is definitely confusion about food additives: about how they work and why they are needed. Fresh, whole foods remain on the top of the priority list, but food additives -- which include preservatives, flavors and colors -- should not be automatically feared. To be sure, they are a mixed lot, but the more you learn, the more you may find that some deserve appreciation.

Some additives are naturally occurring substances, while others are synthesized in a laboratory. All are chemicals, but the same can be said for everything we eat, whether it comes fresh from the garden or in a package on your grocer’s shelf. And what may surprise you is the fact that whether an additive is “all-natural” or chemically manufactured has little bearing on its safety. This is a big and controversial topic, but seeing as you asked about history, that will be my focus.

If you think that food additives are an invention of modern science, think again. For thousands of years, people have added substances to food to maintain or enhance its appearance and taste, and to preserve its shelf life. Cosmetic color additives have been traced as far back as 5000 B.C.; the use of salt as a preservative dates back to 3000 B.C.; sulfite preservatives were used by the ancient Romans; and the use of herbs and spices to enhance taste and appearance, and often to conceal spoilage, has been around since biblical times.

Beginning with the industrial revolution, more and more people moved from the farm to the city. There were more mouths to feed with less land, and food had to be transported greater distances. All this brought about a greater need for foods and food products to remain fresher for longer, and be able to withstand a wider variety of storage conditions. Through the use of food additives, processors could begin to offer a year-round supply of safe, wholesome and convenient foods.

But were they safe? Could just anything be used as an additive? For a long time, there was little control over what was added. Unscrupulous food purveyors could get away with using questionable chemicals to make already-spoiled foods take on the appearance and taste of a more wholesome product. It wasn’t until 1889 that a USDA chemist named Harvey Wiley began to examine the widespread use of additives. His work led to the Pure Food and Drug Act of 1906; the Food, Drug and Cosmetic Act of 1938; and eventually to the Food Additives Amendment of 1958. These laws formed a protective framework that remains in place today.

Today’s food additives are strictly regulated. The testing of a new additive can take several years, and includes a comprehensive battery of chemical and animal testing for a wide variety of potential effects and interactions. The Food and Drug Administration decides on additives’ safety, and regulates their use in foods.

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.