DEAR DR. BLONZ: As temperatures begin to rise, I turn to cooking outside on the grill. Every year I get reminded of the potential dangers of barbecuing and wanted some input about the formation of carcinogens. -- L.G., Tulsa, Oklahoma

DEAR L.G.: Now that warmer weather is in the forecast, the grills of America will spring into action. Cooking food this way does have its “dark” side in that along with adding good taste, it can add potential risk factors. But let’s flesh out this serving of risk by seeing how it fits with other behaviors we face every day.

A key issue is that when you use high heat for cooking protein foods such as meat, pork, chicken or fish, mutagens can form as the food is charred. A mutagen is a substance with the ability to cause mutations, or changes, in a cell’s genetic material. Mutations occur all the time, and most don’t amount to much because our immune system is designed to hustle them away before they mess things up. The danger is certain types of mutations occurring in an unfortunate sequence, in the wrong place and time with the body’s immune system in a state of vulnerability. This can result in a healthy cell turning cancerous.

A key issue with grilling is when fat drippings hit the heat source and become the potent carcinogen “benzopyrene,” which can rise in the smoke and get deposited on the food. (A carcinogen is a substance that causes a mutation shown to cause cancer.) Our immune system is still on the scene, but the greater your exposures, the greater your risk.

Now that we know what can happen when you cook on the grill, let’s discuss its relative risk. No, this is not the risk that your relatives will drop by unannounced; it’s a way to consider one hazard in relation to others. The classic article by Dr. Richard Wilson in Technology Review provides an interesting list of behaviors that increase the odds of death by one in a million. These include: traveling 10 miles by bicycle or 300 miles by car; rock climbing for 1.5 minutes; smoking 1.4 cigarettes; canoeing 6 minutes; having one chest X-ray in a good hospital; spending 20 minutes being a man aged 60; and eating 100 charcoal-broiled steaks.

Bikers, drivers, canoers, rock climbers and especially males over 60 would feel that these risks are acceptable. Given this, the relative risk of eating grilled steaks, while it should be acknowledged, might seem a bit less onerous. The point here is not to dismiss risk in a cavalier manner. If you char your foods, these substances can be formed. If you eat charbroiled foods, they can enter your body. But there are steps to lessen this risk. For example, don’t place the food directly over the heat to prevent the drippings from generating smoke. (Check more ways to reduce the risks when grilling at b.link/fs82gp.)

Finally, don’t lose sight of that big picture. If you are worrying about grilling while sitting in the sun without sunscreen, or are smoking, overweight, with untreated high blood pressure, and with an inactive lifestyle eating an unhealthful diet, your priorities are all wrong. These factors represent a greater risk than the chicken on the grill.

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 continue to hear that the vitamins in foods are superior to those in dietary supplements, but supplement companies claim that theirs are “whole food” supplements -- the same as what you get from food. Does the human body make a distinction? -- G.Q., St. Louis, Missouri

DEAR G.Q.: A vitamin is a vitamin, whether it comes from food or is made in a lab. To the body, that vitamin is an essential chemical that it cannot make on its own in sufficient quantities to satisfy its needs.

That answers your main question, but the discussion does not stop there. If your question had been whether it’s better to get our essential nutrients from foods or out of a bottle, my response would be different.

For perspective, consider that many tales of nutrient discovery have begun as medical studies where animals’ health went awry for unknown reasons. The design of such studies usually includes an experimental group, which receives the treatment being studied, and a control group that receives no treatment. (For the purpose of this example, we will assume that the treatment being studied has nothing to do with nutrition.) To keep the focus on the potential effect of the treatment, both groups receive a similar diet -- usually one that contains all the nutrients known to be essential at the time.

Studies like these might not start as detective stories, but that is what they often become when the control group’s animals fail to thrive in some way. This is the group that should have coasted through the study with no issues.

At that point, attention turns to the conditions of the experiment to see if something there might be responsible. In the early days of nutrition research, it was often discovered that the animals’ supposedly complete diets were missing something. Researchers then isolated and described the needed compounds, which, after extensive study, joined the list of essential nutrients. (For more on the early history of nutrition, see b.link/2nkycj.)

These days, we have good methods to determine what amount of a nutrient is needed to prevent a deficiency, and we have learned that there are, indeed, circumstances where certain people need to supplement. However, science is still working on understanding how nutrients work together, such as how the ratio between two essential nutrients can also affect our metabolism. For example, the amount of zinc in relation to copper may be just as important as the levels of these nutrients individually.

In addition, there is still work to be done on the interactions between nutrients, medications and herbs with the aging process, stress and various other health problems.

“Modern” science will always have an aura of “the epitome of knowledge,” but we are far from knowing all there is to know about health and nutrition. So, while the body might not distinguish between nutrients in food versus identical substances in a supplement, the package most likely to contain the supporting cast for any nutrient is the whole food in which it is produced.

Our lives are a snapshot in time, but whole foods are the packages that continue to be perfected through successive generations. We get the benefit of this noblest of nature’s forces when we head first for the produce aisle, rather than thinking we can get the equivalent from a supplement.

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 enjoy seafood of all types, but I am concerned that some are high in cholesterol. One of the attractions of seafood is that it is generally low in saturated fat, and heart disease runs in my family. How concerned should I be about the high cholesterol levels in some kinds of seafood? -- S.L., San Diego

DEAR S.L.: Animal-derived foods do contain cholesterol; most seafood contains about the same amount as skinless poultry and other sources of lean meat. The most notable exceptions are shellfish, which include crustaceans (shrimp, crab and lobster) and mollusks (clams, oysters, mussels, octopus and scallops).

Shellfish are great sources of low-fat, high-quality protein, but they contain compounds called sterols that are in the same family as cholesterol. Older analytical methods lumped these sterols together with cholesterol, resulting in shellfish being pegged as high-cholesterol foods. Newer testing methods uncovered the oversight. We now know that shellfish have more cholesterol than other fish, but they are not as rich in cholesterol as was once thought. It was also discovered that the non-cholesterol sterols in shellfish can play a role in inhibiting the absorption of the dietary cholesterol that is present.

The connection between dietary cholesterol, blood cholesterol and heart disease is not always clear. Every milligram of cholesterol in our foods does not end up cruising around the bloodstream looking for trouble. Most of the cholesterol in the bloodstream, it turns out, is manufactured by the liver as needed. When cholesterol is absorbed from food, the liver is programmed to make less.

In some people, however, this coordination malfunctions. (Blood tests know as lipid profiles can help reveal this -- another reason to be screened periodically.) Such individuals have to pay closer attention to the type and level of fat and cholesterol in their diets. Lifestyle can also play a role. One problematic nutrient in this scenario is excess sugar. Too much sugar will contribute to a range of health problems, as well as elevated triglycerides and cholesterol.

Fish, especially fatty fish such as salmon, sardines and anchovies, are good sources of healthful long-chain omega-3 fats (EPA and DHA). Assuming there are no allergies or other restrictions, seafood -- including shellfish -- is a healthful category of foods to include in your diet.

DEAR DR. BLONZ: How much does pressure-cooking vegetables deplete their vitamins and minerals? -- S.B., Chicago

DEAR S.B.: Cooking and storing foods can deplete nutrients, to some degree. The actual nutrient losses during cooking depend on several factors, including temperature, cooking time, type of food, size of the food pieces and amount of water used, if any. The amount of loss will vary with the nutrient.

Water can dilute and deplete some of the water-soluble vitamins if the cooking water is discarded. Heat, regardless of its source, can affect fat-soluble vitamins. Because cooking in a pressure cooker typically uses less water and shorter cooking times, more water-soluble nutrients remain.

The most cooking-stable of the nutrients are the minerals. Unless a relatively large amount of water is used and discarded when preparing foods with small particle sizes, most minerals tend to end up on the plate.

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.