DEAR DR. BLONZ: I don’t like overcooked vegetables like broccoli and cauliflower, so I choose to have them raw or cut up in a salad. I tend to stay away from the stems, but wanted to know: How much of these plants should be eaten to provide health benefits? -- T.S., Milwaukee, Wisconsin

DEAR T.S.: The budding broccoli and cauliflower florets at the top of the plant contain the most vitamins, minerals and phytochemicals. This makes sense, as this is the part of these plants that, if allowed to grow, develops into the flowers and seeds for the next generation. Plants have evolved to have significant nutritive and defensive assets in the parts involved with seed development, to help assure the success of the next generation.

As you work your way toward the stem, you transition to parts that are more structural (i.e., dietary fiber) than anything else. From the standpoint of healthful eating, this should be viewed as an additional asset rather than a negative. Dietary fiber is an essential part of healthful eating, and the average fiber intake in the U.S. is about 15 grams a day, which is half the recommended level from the foods we eat. The risk for chronic diseases, such as diabetes, obesity, heart disease, constipation and colon cancer tend to be inversely related to the level of dietary fiber in our diet. We continue to learn about the impact of the microbiome, the population of bacteria that live in our colon, on our health. A healthful, high-fiber diet is also associated with beneficial effects on our gut microbiome, which can also benefit our immune system. I encourage you to give those stems a second chance.

Let’s accept that most people in this country need more dietary fiber. If there are no health issues to the contrary, the goal should be to get fiber from foods, not supplements. But, eating the uncooked stems of cruciferous vegetables such as broccoli and cauliflower might pose a bit of a challenge. Consider steaming them a bit. Other possibilities are to grate the broccoli and cauliflower stems and create a vegetable slaw, or cut them into thin slices and have them sit in a marinade to pick up flavors. For more on dietary fiber, check out b.link/fiber57 and b.link/fiber93.

DEAR DR. BLONZ: Are California wines as good for the heart as French wines? -- S.C., Lafayette, Louisiana

DEAR S.C.: To my knowledge there's been no study that has performed a head-to-head comparison. But research studies on the benefits of wine have come from both sides of the Atlantic. I'd think it safe to assume that the wine made from grapes in both areas would have comparable effects. An important point not to lose here is the fact that diet and lifestyle carry more weight in determining one's state of health than any possible contribution alcohol might make.

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 have been interested in taking niacin for my cholesterol but am concerned that it might be harmful. I get some pretty bad rashes when I take it, like an allergic reaction, but I can’t imagine that I might be allergic to a vitamin. Is this normal and safe? -- H.C., Berkeley, California

DEAR H.C.: Doubtful that you are allergic to niacin, which is indeed an essential nutrient. The daily value for niacin for adults and children (aged four or older) is 16 milligrams per day. What you are probably experiencing is appropriately referred to as a "niacin flush." This is nothing more than a dilation of the small blood vessels near the skin that can occur when a high dose of niacin is taken, usually about 10 times the daily value. It varies from individual to individual, and some can experience a “flush” at much lower doses. You can avoid the flush effect by lowering your intake of niacin, taking it in divided doses, or opting for an extended-release form. There are flush-free forms of niacin, such as nicotinamide or inositol hexanicotinate, but the evidence does not support these as having the same cholesterol-lowering effect. Niacin (also known as vitamin B3, or the related compounds nicotinic acid and nicotinamide) is required for normal cell metabolism and energy release from carbohydrates. Niacin also plays a role in the synthesis of hormones and DNA. Food sources include organ meats, poultry, seafood, nuts, green vegetables and legumes. For more on niacin and its use regarding cholesterol, check b.link/medlineplus54.

DEAR DR. BLONZ: I recently got lightheaded and blacked out. I have no idea why. Could it be from dehydration? Not enough salt? The reason I was not that concerned is that I am in good shape and I bike and run. I have had problems with heat exhaustion in the past. Just curious what you might think it was. I had been getting dizzy when I got up from sitting earlier in the day after a hefty workout. I got up and stood for a minute, and next thing I knew, I was on the floor. Not a big deal, I think I was out for only a few seconds. Any thoughts? -- W.R., via email

DEAR W.R.: I am not a physician, and I have no real handle on other health issues in your life; my advice is that such episodes need to be checked out by your physician. There can be risks in delay, so why take a chance? That said, there can be many explanations for an unexpected loss of consciousness. You have mentioned a few. It could have been a freak intersection of factors that ended up leading to a rapid drop in blood pressure (vasovagal episode). Staying hydrated is important, and if you tend to perspire heavily, it is reasonable to replenish fluids and lost electrolytes when exercising. Anemia is also a possibility. I encourage you to find out what is involved with your situation now, with the help of your doctor.

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: Cereals and fruit have been a part of my breakfast for decades, but about two days after switching to a new brand of cereal, I started to feel that I had become violent, moody and so depressed. I could hardly pick myself up off the floor. Of course, I stopped eating the cereal, and the symptoms did fade. The cereal is the only new food I can recall. Could this have caused this reaction? Any help would be greatly appreciated. -- S.C., Sacramento, California

DEAR S.C.: The first thing to do was to stop consuming any suspect item(s), but also to make a note of any novel experiences or exposures, including eating out, that occurred during this time. It is good that your problem went away, but the cereal, while reasonable to suspect, may not be the answer. It could have been any of a number of things, from something you ate -- including food poisoning -- to an insect bite, to a reaction to a medication you are taking. Given the nature of the reaction, it is in your best interest to do more checking. You don’t want to take on a food fear if it’s not responsible. Consider contacting your family physician or a specialist competent in the areas of allergy and immunology. Seeking assistance makes sense as it is never a good idea to experiment on oneself, especially when missteps might evoke the type of reaction you describe. If your health professionals believe that a food is a likely suspect, they can help you strategize whether and how to test suspect item(s) or to look elsewhere for clues. Uncovering suspect food reactions is a bit of a detective game, and a knowledgeable approach is key. I have heard from many individuals who have written foods or food components off their menu based on faulty logic. You can read more about food allergies and untoward reactions to food components at the website for the American Academy of Allergy, Asthma, and Immunology: b.link/food32. Also, check out the Food Allergy Network: www.foodallergy.org.

DEAR DR. BLONZ: Is it true that black pepper is very bad for you and that it is not eliminated by the body and collects in the kidneys? -- L.A., via email

DEAR L.A.: It is important to appreciate that nature represents a difficult environment, and successful plants will have evolved to produce a custom collection of phytochemicals to assure their growth and continued reproduction. Along these lines, there are compounds in black pepper (Piper nigrum) that might pose a problem, but only if an excessive amount of crushed peppercorns was a big part of your diet. Assuming there are no contaminants in the pepper, and that there is no individual sensitivity to its components, there is no evidence that black pepper is bad for you when used as a seasoning. The idea that something in black pepper collects in the kidneys does not jibe with any information that I have ever seen.

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.