DEAR DR. BLONZ: Does putting milk in my tea (green, black or oolong) affect its antioxidant properties? I have seen and heard mixed answers on this topic. Please clarify it for me, as I do love milk in my tea. It would be very hard for me to stop this habit after so many years! -- T.L., Seattle

DEAR T.L.: First things first: Tea is a very healthy beverage choice. Population studies have suggested that compounds in tea can help reduce the risk of heart disease and other chronic ailments. Having at least one cup of tea per day, for example, has been associated with half the risk of developing a heart attack. This is thought to be due to the ability of certain compounds in tea to protect the fats in the blood (lipoproteins) from oxidation -- hence the term "antioxidants."

In relation to your question, the news is not all good, because a few studies have noted that the addition of milk seems to blunt the tea's antioxidant prowess. The final answers aren't all in, but the "milk effect" theory does seem to have some merit.

Take heart, and understand that tea is not the only antioxidant-rich substance available in our diets. As long as you have a healthful, plant-based diet overall, I encourage you to continue to enjoy your tea the way you like it. After all, eating and drinking should not always be viewed as a clinical prescription; enjoyment must have its place on the plate.

DEAR DR. BLONZ: Can soy products, such as soy milk, interfere with thyroid medication? -- R.S., Portland, Maine

DEAR R.S.: Yes, there is a valid concern here. The hormones produced by the thyroid gland regulate the metabolism in most cells of the body. Those who produce insufficient thyroid hormone are given medications that either stimulate greater production by the thyroid gland, or serve as a replacement for the hormone itself.

There is evidence that soy products can interact with the thyroid gland or its hormones, but not all soy products have the same effect. It doesn't appear that this would be a significant factor in adults eating soy as a part of a mixed diet. With thyroid medication, however, the story has an added level of complexity, because there can be a physical interaction that affects the absorption of the medication when soy is present at the same time.

It is always important to read the instructions and warnings for any medication you take. I say this because soy is not the only food with a potential interaction with thyroid medications. Many thyroid medications have specific instructions to be taken on an empty stomach to avoid potential interactions with foods. Be sure to consult your family physician, or a pharmacist, if you have any further questions.

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: At last year's annual physical, I learned that my triglycerides were over 400. Over the past year, I have been losing weight, and I also started medication for high blood pressure and high triglycerides. My levels are on the way down, but can you tell me exactly what triglycerides do in the body? -- T.L., Teaneck, New Jersey

DEAR T.L.: The role of triglycerides often confuses people. That's not surprising, given the speed with which many complex health terms have encroached upon our daily lives. The triglyceride can be thought of as the body's most concentrated package of stored energy. It is composed of three fatty acids attached to a 3-carbon (glycerol) structure, and can be a fat or an oil.

Fats and oils are usually differentiated by their states at 68 to 72 degrees F, the range referred to as "room temperature." Fats, such as butter or lard, will be solid at room temperature, while oils, such as olive, corn or canola oils, are liquid. (This definition has some wiggle room: Coconut oil, while solid at room temperature, has managed to cling to its "oil" name.) That being said, the term "fat" is generally used to refer to both the fats and oils in the foods we eat.

Triglycerides include the fats in our food, those traveling in our bloodstreams and those hanging around in the body's excess energy storage areas -- and we all know what that means.

We take in energy when we eat, after which our blood triglyceride level rises -- even if there's a limited amount of fat in the meal. This is because the body is programmed to avoid any waste of calories (energy), even if in the form of protein or carbohydrate. Excess energy will be converted into fatty acids by the liver, and then be packed into triglycerides and released into the bloodstream on its way to storage. Food fats are already in the form of triglycerides, but during digestion they are disassembled, only to be put back together after absorption. A high intake of alcohol or of sugars such as fructose, sucrose or glucose tends to increase the blood triglyceride level.

To get an accurate read on one's baseline triglyceride level, tests are usually given after a 12- to 14-hour fast. There can be lab-to-lab differences on what comprises a normal range for blood triglycerides, but generally speaking, levels above 200 milligrams per deciliter are considered high. You can read more about this at tinyurl.com/zps6kf5.

High triglycerides are now recognized as a risk factor for heart disease, which makes perfect sense when you think about it. Simply put, it is not in our best interest to have higher-than-normal levels of fats roaming around our bloodstreams. A high triglyceride level may be more of a risk factor if accompanied by an elevated blood cholesterol level.

Finally, let me offer my congratulations on your strides toward health. High triglycerides are more common in people who carry excess weight, so I wish you success in your continued efforts.

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: Forgive the basic nature of this question, but what is the difference between a vegetable and a fruit? Also, I am interested in becoming a Certified Dietary Manager. How would I go about this, and what are the requirements? -- R.K., Indianapolis, Indiana

DEAR R.K.: A vegetable is an edible part of a plant that has a soft stem. These parts can include leaves (such as lettuce), roots (carrots), bulbs (garlic), stalks (celery), seeds (peas), tubers (potatoes) and flowers (cauliflower). A fruit is the mature ovary in a flowering plant: the fleshy part of the plant that contains the seeds. This means that tomatoes, eggplant, peppers and squashes are technically fruits, even though they are commonly thought of as vegetables.

There was actually a Supreme Court decision in 1893 stating that a plant part typically eaten with the main course was a vegetable, while a plant part typically eaten as an appetizer or dessert was a fruit. (The clarification was sought by a tomato importer looking to avoid vegetable tariffs by classifying his wares as fruit.) I wonder what those justices would say if they had a chance to savor today's cuisines, many of which make use of fruits throughout the meal.

As for your interest in becoming a Certified Dietary Manager, there are a number of resident and correspondence schools that offer training. After that, gaining and maintaining certification means meeting certain career requirements and passing a nationally recognized credentialing exam. For more information, check the site for the Certifying Board for Dietary Managers: cbdmonline.org.

DEAR DR. BLONZ: What is maltodextrin made of? I have called a soup company, two cereal/bread companies and two nutrition stores, and no one knows. I ask because my grandson is allergic to barley. We associate the word "malt" with grains, so we have omitted any product with maltodextrin from his diet, just to be safe -- and it's in a lot of products. I am hoping you can tell me exactly what it is. -- M.S., Sun City, Arizona

DEAR M.S.: Maltodextrins are easily digestible carbohydrates made from starch. The starch is cooked and then broken into smaller pieces -- similar to what happens when starch is digested. As additives, maltodextrins serve as texturizers or flavor enhancers. According to FDA regulations, manufacturers should use use corn, potato or rice as the source of the starch for any maltodextrins used in foods. Note that this may not be the case for maltodextrin used in medications.

Where allergies are involved, it is best to use caution; even though there are regulations, there is no guarantee that a particular manufacturer won't use a different source for its starch. For any specific products your grandson might consume, you should consider contacting the manufacturer and requesting further information about their maltodextrin supplier.

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.