Large studies like the China Study (and numerous other studies, including the Oxford Study and repeated studies on Seventh-Day Adventists) have clearly shown health benefits from a vegetarian diet. As a whole, the research on diet and health shows better protection from disease when a vegetarian versus non-vegetarian diet is followed. We believe that the research lends support to any personal decision to follow a vegetarian diet and that a high-quality vegetarian diet can provide outstanding nourishment and health.
However, we still chose to include lean meat and poultry in the World's Healthiest Foods for three basic reasons: (1) these foods have research-tested health benefits, (2) they are a rich source of certain nutrients that are often found deficient in the average U.S. diet, and (3) some people really enjoy these foods and feel much better when they are included as part of their diet. We don't believe that lean meats and poultry are for everyone, or that they are a required in a diet. Nor do we think about them in the same way that we think about vegetables, fruits, legumes, whole grains, nuts, or seeds. But the potential benefits of lean meat and poultry in a healthy diet are many. Here are more details about those benefits and your best way of obtaining them.
In the average U.S. diet, about one half of the zinc and about one-quarter of the iron come from meat, particularly beef. While you cannot rely on lean meats to meet all of your zinc and iron needs and still need to include other zinc- and iron-rich foods in your overall diet, lean meats can make a major contribution for both nutrients. Perhaps the most dramatic example of meat as a key nutrient source, however, is vitamin B12. The average U.S. diet only provides less than half of the DV for this nutrient, and lean beef can provide exactly half of the DV for vitamin B12 in one 4-ounce serving. Of course, there are other very good sources of vitamin B12 in the World's Healthiest Foods (like salmon), and good sources of zinc (like sesame seeds or pumpkin seeds) and iron (like lentils, or dark green leafy vegetables) as well.
Fortunately, research studies have shown that you can eat lean cuts of beef and still enjoy the full benefits of its zinc and iron and vitamin B12. If you enjoy beef and do well when it is included in your diet, these findings are important. They make it clear that you can enjoy these nutrient benefits of lean beef while simultaneously avoiding potentially unwanted levels of saturated fat and total fat in non-lean cuts.
Unlike many former research studies on meat that did pay attention to the difference between high-fat and low-fat meats, recent studies have looked at these types of meat and come up with some often unexpected findings. For example, did you know that when a moderate amount of lean beef (5-6 ounces cooked) is substituted for foods like breads and pastas and rice in the diet, there's a slight decrease in the likelihood of inflammation and oxidative stress? Since unwanted inflammation and oxidative stress are risk factors for heart disease and type 2 diabetes, this research suggests that individuals who enjoy a moderate amount lean beef can do so without worrying it increasing their risk of these two potential health problems. Similarly, in recent research where two-thirds of all daily protein came from either lean beef, lean poultry, or lean fish, lean meats were found to help lower levels of total cholesterol and LDL cholesterol as effectively as lean fish. (The lean fish did provide one health benefit that the lean meats did not, however, and that was the increasing of HDL cholesterol.)
These lean meat studies stand in clear contrast to studies on meat in which fattier meats and processed meats are included. In those studies, the higher saturated fat content of fatty meats almost always shows a trend toward increased disease risk, especially coronary heart disease. The take-away message here seems especially clear: if you enjoy meats and decide to include them in your diet, stick with lean cuts only and keep the amounts to a moderate level.
If you're trying to decide between lean red meat (like beef round steak) and lean poultry (like skinned chicken breast), there's evidence that moderate amounts (6 ounces or less) of both can work equally well in lowering LDL cholesterol level (if your LDL cholesterol is too high). In addition, although the evidence is not as strong and involves some mixed findings in various studies, there may be a potential for lean meats to slightly raise your HDL cholesterol as well. i On balance, these findings are good news for anyone with cholesterol problems who would like a variety of meat options and still wants to follow a program like the National Cholesterol Education Program's Step 1 Diet.
If you enjoy meat and feel better when meat is part of your diet, lean meats can make important nutrient contributions to your weekly diet. In addition, if kept to a moderate level of 5-6 ounces and woven into a healthy overall diet, lean meats can do a good job of keeping your heart disease and type 2 diabetes risk factors in check. The key here is lean! Fattier meats provide excess saturated fat and total fat and increase your disease risk factors. Stick with cuts of beef like top round, bottom round, or eye of round, and white meat poultry including skinned chicken breast. If you feel like you do better with no meat whatsoever in your diet, you can omit lean meats completely and still stay optimally healthy; just make sure that some of the key nutrients provided by lean meats — like protein, zinc, vitamin B12, and iron — are provided in ample amounts from the foods you choose.