DEAR DR. BLONZ: In doing a research paper on health issues faced by indigenous peoples, I came across the issue of the Pima American Indians in Arizona, who have a very high incidence of Type 2 diabetes. Is this a genetic issue, or a dietary and lifestyle issue? -- J.D., Casa Grande, Arizona

DEAR J.D.: It’s both. The Pima appear to have a genetic component that is not serving them well under the current style of eating in the United States. It is called a thrifty genotype, and it provides survival advantages when there is an irregular food supply by conferring maximum efficiency in the processing and utilization of dietary energy (calories).

Pima Indians live in northwest Mexico and the southwestern U.S., having migrated there from remote mountainous regions in Peru, where a good number remain. In these areas, there is an inconsistent food supply throughout the year. Over the millennia, the Pima in Peru and Mexico adapted to the sparse availability of food in these regions, and as a group, they tend to be slim and do not suffer from Type 2 diabetes.

The Pima who migrated to what is now the United States, however, no longer have to cope with an irregular food supply, and are now experiencing an epidemic of obesity and Type 2 diabetes attributable to this environmental change in their diet.

Insulin resistance and hyperinsulinemia have been identified in the Americanized Pima Indian population. Scientists from around the world continue to study this population because it offers a rare insight into the independent roles of genes and environment on the risk of disease. Studies continue to report on the critical roles of food selection and increased physical activity in helping reduce the risk of Type 2 diabetes in this population. There is an interesting discussion on this topic at b.link/pima85.

DEAR DR. BLONZ: I need to up my level of dietary fiber. I want something convenient, but I am seeking taste, not cardboard. What do you consider to be the best foods that are rich in fiber? -- N.F., San Jose, California

DEAR N.F.: Americans tend to eat rather low on the fiber scale, and population studies continually find that increased consumption of dietary fiber is associated with a range of health benefits.

In terms of convenience, there’s no better way to start the day than with a bowl of fiber-rich whole-grain cereal topped by some fresh or dried fruit. Setting the requisite time aside in the morning to have a healthful breakfast can be an important adjunct to your health.

With or without the cereal, dried fruits are on my list of excellent fiber-filled foods. They are an often-overlooked fiber source with a great variety of rich fruit flavors, and the fact that they are dried gives them an extended shelf life. Combining them with various nuts and seeds, even tossing in a few dark chocolate chips and coconut flakes, makes a healthful, fiber-rich snack or mini-meal that can be available throughout the day. This mix is also a great real-food option for your child’s lunchbox.

Next, we have vegetables, whole grains and legumes (beans), all of which have a high fiber content. No cardboard on that list. Fiber supplements can have a role, but first, focus on foods naturally high in fiber. They come with an assortment of other important nutrients and phytochemicals. For more, check the FDA’s fact sheet on dietary fiber at b.link/pdf34.

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: On a TV show, I watched a hospital nutritionist cook a chicken breast by putting it in a resealable plastic bag, submerging it in a pan of water, bringing the water to a boil, turning off the heat and letting the pot rest for two hours. I am skeptical of this method, because it doesn’t seem that the meat stays hot enough for long enough to be safe. In fact, it sounds like a recipe for promoting bacterial growth, not to mention the dubious wisdom of boiling a plastic bag. What do you think of this cooking method? -- A.M., Castro Valley, California

DEAR A.M.: First, it should be noted that, while it may sound similar, the method you describe is different from “sous vide” -- an established cooking method gaining popularity in recent years. (More on sous vide below.)

The main concern with any poultry, no matter how it’s cooked, is salmonella bacteria. In the process you describe, a chicken breast is put in a plastic bag, which is then put into a pan of water that’s brought to a boil (212 degrees F). That’s well over the temperature needed to kill those bugs. However, meats are only as safe as the least-cooked portion, and chicken breasts come in a range of sizes and thicknesses.

Our question, then, becomes: Once the heat is turned off, is the thermal mass of the pan and the boiled water sufficient to raise the internal temperature throughout the entire piece of chicken to a level sufficient to zap the bacteria?

According to the FDA, the safe minimum temperature for poultry is 165 degrees F (see b.link/food51). But it should be understood that time is a factor, as well as temperature. For example: Most recommendations say to cook poultry until a thermometer reaches at least 165 degrees F in the thickest part of the meat. It will then be safe to eat. But if the poultry is cooked to 145 degrees F and kept at that temperature for at least nine minutes, you could accomplish the same elimination of bacteria. That, however, requires closer attention to the cooking process, not a one-time temperature read. (Check out the interesting discussion of time and temperature poultry cooking at b.link/chicken97.)

So, how can we be assured that the technique you saw will produce chicken that is safe to eat? That TV technique presents risk variables, with no real way of assuring the safety of the results. The bag must be a material suitable for boiling, and since air is not a great conductor of heat, there must be a step to draw all air out of the bag, such as with a vacuum-sealing device. Handling must eliminate risks of cross-contamination from surfaces that touched the uncooked poultry. Another variable is how rapidly the water temperature drops after boiling. It will cool at one speed if using a metal pan in a cool room, and another if resting post-boil on a conductive surface that drains the heat.

These factors -- the bag material, the presence or absence of air, the chance of cross-contamination, and the water-cooling speed -- are all potential risks. So without testing, this is not a method I could recommend.

You might instead consider the sous vide method. Here, the food is put into a bag, the air is removed, and the bag gets submerged in water that is then heated to around 145 degrees F and kept there for one to four hours. The advantage here is that the sous vide device heats the water to a specific temperature, then circulates and maintains it for a set period. (For more on sous vide, see b.link/vide10.)

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: Six months ago, I moved into a wonderful apartment that included some furnishings. The kitchen table appears to be constructed from an old painted door. It is beautiful and solid, but what concerns me is that that I noticed a powder on the surface when I moved in. I keep the table clean and have always used a tablecloth, but one of my friends told me that there could be lead in the old paint, and that this could be dangerous -- pointing out that the tablecloth and my cleaning would not provide any real protection.

I need more information about this risk, and about how best to determine whether there is any lead on this door. There are no children in the apartment, but I do have a dog and want to be certain that neither the dog nor I am in danger. -- J.S. Anderson, South Carolina

DEAR J.S.: You are right to be concerned about lead. This potentially toxic substance can enter the body in a number of ways, the most common being the consumption of substances containing lead, or the inhalation of lead in dust. Lead poisoning in children, for example, is often related to the consumption of leaded paint chips that peel off walls and other surfaces, or by putting toys that contain lead dust in their mouths. (This could also be an issue with dog toys, in your case.) For adults, leaded water pipes are a common source of lead poisoning. Others include cooking in, or eating on, pottery that is rich in lead; consuming food or liquids that have been stored in leaded containers; and working in industries that use lead compounds.

For you, a prudent first step is to determine whether there is any lead on the door, or elsewhere in the apartment. There are products to help with this, many available at your local hardware store, or online. I have used the LeadCheck swabs made by 3M, but there are other brands, and any can provide the information you need. Most involve a color indicator that reacts to the presence of lead, changing to a specific color if lead ions are present. The tests are simple and straightforward, and will let you know instantly if your painted table -- or any surface or object -- presents a risk.

There are blood tests to determine if the body has been exposed to excessive lead. Speak with a physician for a precise evaluation. The body can rid itself of lead, albeit slowly. The first step is to identify and stop the exposure.

The symptoms of lead poisoning in adults can include anemia, fatigue, depression, high blood pressure, heart failure, abdominal pain, gout, kidney failure, wrist or foot weakness or reproductive problems. In children, lead poisoning symptoms include anemia, fatigue, decreased appetite, digestive problems, sleeplessness, learning problems and lowered I.Q.

The Environmental Protection Agency has information on a variety of issues relating to lead: epa.gov/lead.

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.