DEAR DR. BLONZ: In a recent column about digestion and gas, I felt you should have mentioned probiotics. I have friends who swear a daily probiotic has changed their lives. I take one also and have had good results. I enjoy your column very much. Thank you. -- S.R., Contra Costa, California

DEAR S.R.: Thank you for your comment, which raises an important topic. Most have heard of the term "microbiome," which refers to the community of microbes that live in our large intestine; it is also referred to as the intestinal flora. Despite their reputation for contributing to ill health, not all bugs are bad. Microbes, which for our discussion will include bacteria, viruses, fungi and archaea, play an important role in helping maintain the ecology in the digestive system. Clinical studies reflect their impacts on our overall health.

However, there are also ones that are not so friendly. Think of the microbiome like the Wild West without a sheriff, where survival is the name of the game. All the players seek to multiply, but it is in the interest of good health that we eat and behave in a way that keeps our microbial allies ahead of the game.

Probiotics are the friendly bacteria; a probiotic food or supplement contains these bacteria. Several probiotic strains can survive in your intestines. A related term, "prebiotic," which is addressed in greater detail below, refers to a food that facilitates the growth and survival of probiotics by providing the nourishment they require.

In the early 1900s, Elie Metchnikoff, a Russian biologist working at the Pasteur Institute in Paris, proposed that health and longevity were linked to the type of bacteria living in the intestines. In his 1908 book "The Prolongation of Life," Metchnikoff attributed the health and long lives of Balkan tribes to the bacteria used to make the yogurt that was a staple of their diet. Milk products have proven to be popular probiotic foods because they are easily cultured to grow these bacteria. The common culturing strains are s. thermophilus and l. bulgaricus.

In addition to yogurt, milk products such as kefir, low-fat acidophilus milk and buttermilk contain these bacteria and can also have added l. acidophilus or bifidus (bifidobacteria) -- friendly bacteria equipped to establish themselves as long-term residents in the large intestines. Always check the label to see what is in products you are considering. Other foods containing friendly bacteria include sauerkraut (fermented cabbage), kimchee, miso soup, tempeh and natto. The friendly bacteria are also available as a dietary supplement. For more on probiotic foods, see b.link/breafb7. For a probiotic pro and con, see b.link/ph7772f.

Prebiotics, an associated topic, are foods with elements that can bypass normal digestion. When arriving in the large intestine, they can serve as nourishment for the microbiome. Foods such as legumes, peanuts, garlic, onions, leeks, Jerusalem artichokes, wheat, barley, asparagus, rye, chicory and berries contain constituent substances that feed the intestinal flora. There are also substances known as fructooligosaccharides (FOS) and inulin, which have a special ability to reach the large intestine intact. (You may see these as ingredients in supplements.) Be sure to discuss any intestinal health issues with your physician and express your interest in opting for a probiotic with the best organisms in the best dosage for issues you face.

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 respect your expertise and skepticism, but feel the need to vent about your rejection of all that's alternative, much in the same way that medical doctors do. I hear about many successes involving alternative medical treatments, where the doctor says, "I don't know what you are doing, but keep doing it." Current medical education has fallen short in addressing alternative medicine. -- S.F., St. Paul, Minnesota

DEAR S.F.: I am not against all things new and will not reject something simply because it is "alternative." At the same time, I am not in lockstep with all things mainstream. Ours should be a system that tests, verifies and efficiently integrates new treatments. Research takes funding and time, however, and people understandably clamor for any new product as soon as they hear it might help in their situation. Evidence is not always within easy reach.

Given your question, how would you expect a medical doctor to react if a patient relates that some nontraditional therapy has "worked" for them? There is a danger, especially with social media, when people broadcast their experience with a product or treatment as being something that will work for all, but there is no clinical evidence to support the claim.

Don't lose sight of the fact that a properly nourished and cared-for body is designed to fix what it can, but it can take time. Say you are trying a series of products to find one that helps. Was the one you were using at the time things improved really the one that worked? Or was it your body's innate capacity for healing finally getting the upper hand? That is why testimonials are unreliable.

Objective clinical testing, that would ideally include the use of placebos, is needed to provide a controlled examination of whether and under what circumstances something can be effective. Be skeptical if the origin of their claims involves a product being sold by those having a financial interest in its success.

There is no question that alternative medicine has its allure. To an individual dissatisfied with the medical establishment, or to one frightened by disease, discomfort and pain, the temptation to try something that promises benefits can be irresistible.

There may be situations where it helps, but in others, it can lead to frustration compounded by a waste of one's time and money. Time is key here. With certain health conditions, delaying the initiation of proven, even if only marginally effective, medical therapy can result in tragedy, allowing for the progression of a treatable condition into something much more serious.

Those who profit from alternative treatments should shoulder the burden of substantiation before being able to make claims of success, and they should do so with research providing competent and reliable scientific evidence. At the same time, there is a definite responsibility that falls upon scientists, educators and health professionals to be objective and open-minded.

There is nothing wrong with being new and different; many of the treatments that are currently in the mainstream were once considered revolutionary. Being reflexively dismissive of alternative approaches is not the way, but where health is concerned, the concept of "let the buyer beware" takes on special importance.

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 would appreciate your thoughts on the discussion about aluminum foil that occurred at a recent dinner event. There was acknowledgment of its many uses and the plus that it is recyclable. There was also mention of a connection between aluminum and the risk of cognitive decline, such as with Alzheimer's disease, and this was a source of underlying concern. My more specific question is whether it is best to use the shiny side or the dull side of the foil when placing it next to the food. The argument in need of clarification was whether the shiny side or the dull side best reflects the heat, and also which side is best for nonstick properties. -- S.R., San Francisco, California

DEAR S.R.: Beginning with your question, the shiny and dull sides of standard or thick aluminum foil are a result of the manufacturing process. They don't reflect any different functional purpose, including differing heat or anti-stick properties. (See an explanation of how aluminum foil is made at b.link/c3wdz7m.)

There are nonstick aluminum foils that use a proprietary food-safe anti-stick coating; check with the brand to see how they achieve their effect. Nonstick aluminum foils will indicate this property on their package label, and in such products, it is the dull side that has the property. If using one, verify it retains its recyclable properties. On a more practical note, rinse food debris off any foil or other recyclable materials before placing them in the recycling bin.

The issue regarding aluminum as a risk factor for disease is somewhat more nuanced, as its primary foundation lies in epidemiology. Epidemiology, often thought of as "population studies," is the science that investigates the connection between specific events, such as the occurrence of a disease, and particular behavior patterns, including elements of diet or exercise. Epidemiological research doesn't explain what's going on; it can reveal suspects and suggest relationships that require clinical studies designed to uncover cause-and-effect relationships, often involving the use of controls, such as a placebo.

Key in epidemiology is the need to understand what causes what. An example can be seen in reports that inner-city children with iron-deficiency anemia are more likely to have lead poisoning. The population study revealed the connection, but it did not identify the cause. Scientists conducted additional studies to uncover the underlying mechanism. In this case, it was discovered that low blood iron (anemia) causes the body to absorb more lead. Inner-city children are at a greater risk for substandard nutrition, coupled with increased exposure to lead that is present in lead-based paints, which may be peeling off the walls.

In some cases, epidemiology yields strange results. I recall a classic example during a graduate course in epidemiology that physicians who eat more meat and consume more alcohol have one-third the risk of dying in a plane crash. Anomalies with no logical relationship can emerge in large population studies, and this particular finding does not justify encouraging doctors to grab a burger and a beer before they board their flight.

Regarding aluminum, there is no evidence that the use of aluminum foil causes problems when consumed at normal levels found in food, as well as those levels added through normal cooking and storage. For a more focused consideration of this aspect, please visit b.link/aluminum.

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.