Ease transition to a meat-free diet

Q. I have been attempting to shift over to a vegetarian diet. I now eat a healthy, well-balanced diet with the exception of meat, but I do eat (organic) dairy products and fish at least once a week. I have heard many things concerning the lack of proteins and the lack of one kind of vitamin B. Do these stories have any validity? Should I be taking a certain supplement in addition to my multivitamin? Thanks.

A.H., Walnut Creek, Calif.

A. 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. Though some gains are connected to the lifestyle that's frequently adopted along with the new eating habits, these findings are certainly impressive.

Protein is rarely a problem for vegetarians eating a varied diet. For the vegan who gives up all animal products (meat, fish and dairy), traditional sources of essential nutrients like calcium, iron, zinc, vitamin B-12 (the "b" you were referring to), vitamin D and riboflavin (vitamin B-2) are less available. You can get all of these nutrients in foods, but if you want a supplement for added insurance, these would be the ones to look for. In your case, the inclusion of dairy and fish makes this much less of an issue.

In general, becoming a successful vegetarian means learning which foods are required for a complete diet. These food selections and combinations become very important, especially with children and pregnant or lactating women.

There are resources you can consult for more specific information. The Web site www.nutritiondata.com provides a breakdown of the foods you are considering, and it can suggest those that are rich sources of specific nutrients. There are a number of excellent books for those interested in vegetarianism.

Ones that come to mind include "The Gradual Vegetarian" by Lisa Tracy; "Vegetarian Times: Vegetarian Beginner's Guide" by the authors of Vegetarian Times magazine; "Vegetarian Cooking for Everyone" by Deborah Madison; and any of the vegetarian cookbooks by Mollie Katzen.

There are many more, and I suggest you visit your local bookstore or library, scan through what is available and find a book that fits your needs.

Q. I am doing a research project on the Pima Indians in Arizona, who have a high incidence of diabetes. Apparently, the incidence of diabetes has continued to climb yet higher over the last couple of decades, such that about 80 percent of Pima are affected. Do you have any info on this matter? Is there a clear, specific genetic component involved, or are the Pima pretty much representative of what happens when anyone has a high-carb/low-fat diet and not much exercise? Surely they have tried a low-carb diet?

D.W., Beaver Dam, Wis.

A. There is a fascinating story here. The Pima Indians appear to have a genetic component that is not faring well under their current style of eating. It is called a thrifty genotype, and it confers special advantages when the food supply is irregular and the environmental conditions are harsh.

A number of Pima Indians are found in northwest Mexico, having migrated there from the remote mountainous regions of Peru, where a good number remain. In both these areas, there is an inconsistent food supply throughout the year. The Pima in Peru and Mexico have 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.

There are Pima, however, that have migrated to the Southwest United States, where they no longer have to cope with an irregular food supply. Those Pima are suffering from 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 fascinating insight into the potential interplay between diet, genetics and disease.