Sunday, November 25, 2007

Meat vs. the Alternative

Just a few short days ago, I sat down to enjoy Thanksgiving dinner at a friend's house and discovered that she was serving a dish known as "Tofurkey." It looked and smelled like turkey, but as you may have guessed, it tasted nothing like the traditional Thanksgiving bird. Not that it tasted bad, mind you, just different.

The popularity of what are commonly referred to as "meat alternatives" (such as Tofurkey) is on the rise. Alternatives to meat include such products as tofu (made from soybean curd) eggs, seeds, nuts, legumes and complementary vegetables and grains. According to one source, sales of meat alternatives have increased by almost 89 percent during the past four years. It's estimated that over 12 million people in the U.S. are vegetarians and greater than 77 million are working to decrease their intake of red meat. Different reasons for this trend include growing concerns about the ethical treatment of animals, global ecology, and health and wellness. The health benefits of choosing meat alternatives over meat may be related to dietary fat intake and phytonutrients present in foods of plant origin. Many animal products tend to be high in saturated fat. Epidemiological studies suggest that those who consume large amounts of animal products high in this type of fat are at a much greater risk for developing certain types of cancer, heart disease, diabetes and arthritis.

Even so, meat is considered an important part of a well-balanced diet because it is a good source of protein and is needed for growth and maintenance of a healthy body. Proteins are comprised of amino acids, nine of which are essential to human beings. The body either cannot make or cannot synthesize enough of these particular amino acids and must be obtained in the diet. The importance of a complete array of essential amino acids cannot be stressed enough. They are the "building blocks" of proteins within the body, the functions of which include fluid balance, immune function, muscle growth and maintenance, and structure. In addition to protein, meat is a valuable source of nutrients such as iron and vitamin B12. The downside is that certain types of meat are also high in saturated fats.

If you are thinking about incorporating meat alternatives into your diet, one factor to consider when choosing a product is protein quality, a term which encompasses completeness, complementarity and digestibility. Food choices that are low or deficient in certain amino acids are considered poor quality. In general, most animal-derived products are complete proteins. Eggs contain high-quality proteins and are considered references for measuring other types of protein. Similarly, yogurt, milk and cheese are also good alternatives to meat. Proteins of plant origin tend to be lacking one or more amino acid, which brings us to the idea of complementarity. It is usually necessary to combine certain plant foods in order to obtain a complete array of amino acids. Such combinations include beans and rice, or tortillas and refried beans. Digestibility refers to a protein's ability to be broken down into component amino acids and absorbed by the body. This characteristic is dependent mainly upon configuration and other factors in foods eaten with it. Because meat contains a substance known as intrinsic factor, it is more easily absorbed and digested than plant sources. It is very important to consider all aspects of protein quality when planning meat-free diets.

Can foods of plant origin provide us with enough protein to make it worth our while? Yes. The recommended daily allowance for protein is 0.8 grams per kilogram of body weight per day for adults, or approximately 15 percent of the daily caloric intake. That's roughly 75 grams of protein per day for someone consuming 2,000 calories. In terms of protein content, one 50-100 gram serving of meat is equivalent to one or two eggs, two tablespoons of peanut butter or 1/3 cup of tofu. Beans in particular are great alternatives because they contain no cholesterol, are high in soluble fiber and vitamin A, and are good sources of protein. In fact, tofu contains more protein than steak on a per-weight basis. However, the protein in meat has a higher bio-availability than that in plants. But with over 70 different varieties of tofu to choose from, many different tastes can be accommodated. Many commercially available products are now available, many of which are soy-based and include items such as texturized vegetable protein and tofu.

Plant-based foods also contain phytonutrients, substances that have generated quite a lot of interest in the nutrition field in recent years. Things like bioflavonoids, carotenoids, isoflavones and others are considered phytonutrients. Some, such as carotenoids have been studied extensively and are known to act as antioxidants. Others include genistein and lycopene, and are under further investigation. The isoflavone genistein is derived from soy and is believed to help lower cholesterol, prevent certain types of cancer and decrease bone loss after menopause. Lycopene is found in tomatoes and may help prevent prostate cancer. These are just a few examples of the potentially beneficial phytonutrients found in foods of plant origin. So even if you enjoy meat too much to ever become a vegetarian, consider trying a meat alternative on occasion. Who knows, you may find that products like Tofurkey are pretty tasty.

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