DEAR DR. BLONZ: As one with lactose intolerance, I pay the price with unwanted digestive gas if I eat dairy products that contain lactose. I now have milk without lactose, but wondered why lactose-free dairy is not made into yogurt or cottage cheese. I haven't found such products at the market, and they would be excellent additions to the selection. -- J.D. Tulsa, Oklahoma

DEAR J.D.: This would be a good discussion to have with a local store manager. As background, most people are born with the ability to produce their own lactase, which is the enzyme that breaks lactose down before absorption. But some of us lose the ability to produce sufficient lactase as we become adults. In these individuals, lactose consumption can give rise to G.I. upset.

The bacteria used to make cultured dairy products, like yogurt or cottage cheese, produce their own lactase, which allows them to use lactose as fuel. Culturing organisms can also use other carbohydrates, meaning that unsweetened products are likely to have more lactose broken down for fuel.

Lactase present in the "active" cultures continues its work until it, as a protein, is broken down in stomach acid. Dairy products do contain acid-buffering compounds (many of which are calcium-based), so this breakdown is slowed a bit. But this is not an "all gone" phenomenon; yogurt and cottage cheese are considered to be very low-lactose, not lactose-free, foods.

There are now lactose-free alternatives for those who cannot tolerate much more than zero grams. I am lactose-intolerant, but can handle small amounts of it. I have been using an organic, plain, whole-milk kefir -- either regular or lactose-free -- for my morning cereal (usually high-fiber, whole-grain granola with fresh fruit). Kefir might be thought of as a pourable yogurt; it is made with culturing organisms similar to those found in yogurt.

There are also nondairy options to sidestep the lactose issue entirely. Finally, there is the option of taking a lactase supplement with a meal to assist with the lactose stragglers.

DEAR DR. BLONZ: I understand weight-bearing exercises are beneficial for the bones. My mother has recently recovered from a stroke and can no longer walk. She is doing exercises daily, but not of the aerobic variety -- they are arm or leg exercises, performed sitting down, with light weights strapped to her ankle or wrist. We are also using stretch bands to work her muscles. Are these the same as weight-bearing exercises? --W.L., Detroit

DEAR W.L.: Congratulations on your mother's progress, and kudos for your help. I trust she is taking it slowly.

Strength training using weights is indeed considered a weight-bearing exercise. Given her condition, these activities sound reasonable, and may be her best option. Most other weight-bearing exercises involve movements such as walking or jogging, where the weight of the body is repeatedly applied and then removed from the long bones of the legs.

Stretch bands also work the muscles, but they have different tensions and need to be used properly. It is best to work with your mother's health professional, especially with a physical therapist who has expertise in this area.

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: You mentioned that excess dietary protein could increase mineral losses in a recent column. Can you say more about that? Is excess protein hard on the kidneys that have to filter out all that nitrogen, too?

Many Americans do eat excessive protein, whether because of high-protein diets like paleo, our addiction to and overindulgence in meat, or the intense marketing of protein shakes/bars. Are we harming ourselves via mineral loss while also damaging the environment by raising and consuming so much meat? -- L.F., Pleasant Hill, California

DEAR L.F.: Proteins, which are made up of chains of amino acids, are involved in many functions (for details, see b.link/m6n36h). There is, however, no practical way for the human body to store unused protein for later use.

When we consume more protein than the body needs, the excess gets converted to energy (fat) -- something the body is quite efficient at storing. But before this conversion can take place, the amino group must be removed from every amino acid. This becomes "ammonia" waste, which ends up in queue for disposal through the urine. As long as we are adequately hydrated and nourished, there shouldn't be any problems having our kidneys carrying out this routine assignment.

Amino groups on their own have negative charges, meaning they need to pair with positively charged "escorts" before they can leave the body through the urine. Calcium ions have a positive charge and can serve this purpose, but they are not the primary or only choice for this role. There are plentiful positive buffering compounds in any balanced diet with healthful amounts of fruits and vegetables. If, however, little else is around, calcium -- which is always present in the blood -- can get the call. If significant calcium leaves the body in this way, hormones will cause calcium to be pulled from the bones to maintain the required blood level.

The bottom line is that some calcium can indeed be lost when one eats a high-protein diet, but this will be more of an issue with diets lacking the recommended balance of plant foods. Unfortunately, the people who overdo it with protein often lack such well-balanced diets.

Finally, as to your last point: Shifting from a diet that is heavy on animal/protein foods to one that is more plant-based is, indeed, healthier for the environment. A paper in the August 2015 journal Public Health Nutrition studied this topic. The paper reported that producing a pound of protein from beef required approximately 18 times as much land, 10 times the water, nine times the fuel, 12 times the fertilizer and 10 times the pesticides as producing the same amount of protein from legumes, such as kidney beans.

We should all be aware that even minor dietary shifts to include more plant foods can help us all, if done by enough of us.

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 READERS: I am encouraging all who can, and haven’t, to get vaccinated against the SARS-CoV-2 virus and the disease known as COVID-19 that’s wreaking havoc around the world. The longer significant numbers of people refuse to take the shot, the greater the risk that increasingly nasty variants can emerge. Even more worrisome, the unvaccinated risk serving as vectors to infect their own families, friends, and any vulnerable people around them.

I have followed the research behind the vaccines' development, and have confidence in their safety and efficacy. This is good science, marvelously developed with fantastic speed.

Personal freedoms notwithstanding, we must all act responsibly. Who wants to get sick or be responsible for making those around us ill to express some twisted point? Please step up and contribute to the end of the pandemic rather than fostering its continuance.

DEAR DR. BLONZ: I am interested in the "complementary protein" approach to vegetarianism, as my family has decided to move in that direction. One of the motivations for the shift was an online presentation we attended about how this way of eating can help slow climate change. The switch has been difficult, and I would greatly appreciate knowing your position on the subject. -- J.T., via email

DEAR J.T.: Proteins are composed of chains of individual amino acids bound together and folded into three-dimensional arrangements specific to their function. Our body can make most, but not all, of the 20 amino acids it uses; nine need to be provided in the foods we eat. These nine essential amino acids (EAAs) are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. When we eat protein, the enzymes of digestion break it into its amino acid parts -- a necessary step before absorption. We need a regular supply of all the EAAs to make our protein, but it makes no difference whether they come from a “protein” food that has them all or from a combination of other foods with one or more amino acids that, combined, provide what the body requires.

The environmental motivation behind your family’s decision is on solid ground. Current estimates place the carbon footprint of a vegetarian diet at about half that of a meat-heavy diet.

One other item: Your overall health could also benefit from this shift. Health statistics for groups of vegetarians include lower rates of heart disease, obesity, obesity-related diabetes, colon cancer, lung cancer, breast cancer, hypertension, osteoporosis, kidney stones, gallstones and diverticular disease. These data are also affected by lifestyle changes that often accompany a shift to new, healthful eating habits.

Finally, there can be some bumps, both at home and out socially, when making major changes to your eating habits. This does not have to be an all-or-nothing project. Any move toward bringing a greater proportion of plant foods to the family plate is a healthful one.

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.