Phytochemicals (Lesson 11, Part A)

Phytochemicals - Yet Another Reason to Eat Your Plant Foods

Introduction

Eating more broccoli, tomatoes, citrus fruits, onion, soybeans and other plant foods may help to protect you against several chronic diseases such as heart disease and cancer.

And it is not just because of the nutrients they contain. It is more likely because of the chemicals found in these foods - phytochemicals.

Activity:

Think about the different colors in a rainbow and where you would place different foods.

What are Phytochemicals?

Phytochemicals (pronounced fi-toe/chemicals) are naturally occurring components in fruits, vegetable, legumes and grains. They are non-nutrients because they are not considered essential at this time; however, phytochemicals have many beneficial functions in the body such as getting rid of free radicals.

The term phytochemicals means chemicals found in plants. They give a plant its color, flavor and smell and are a part of a plant's natural defense system. It is these defense qualities in phytochemicals that have researchers intrigued because those same qualities may also benefit humans. Researchers believe phytochemicals could go a long way in helping to reduce the risk for several chronic diseases including heart disease and cancer.

How Do Phytochemicals Work?

There are thousands of different phytochemicals with possible health benefits of which only a fraction have been studied. Much of the research done on phytochemicals has been with animals or in test tubes. Within the last few years, scientists have studied many of the phytochemicals' effects in humans. Many studies have also been done either retrospectively or prospectively. A large group of individuals is studied, data on food intake and disease conditions are assessed and relationships are drawn.
 
The Nurses' Health Study, established in 1976 by Dr. Frank Speizer, and the Nurses' Health Study II, established in 1989 by Dr. Walter Willett, are among the largest prospective investigations into the risk factors for major chronic diseases in women. The studies have grown to include a team of clinicians, epidemiologists and statisticians at the Harvard Medical School, Harvard School of Public Health, Brigham and Women's Hospital, Dana Farber Cancer Institute, Boston Children's Hospital and Beth Israel Deaconess Medical Center. Many of the conclusions drawn based on these studies support increased intake of photochemicals for combating chronic diseases.

For example, when it comes to heart disease, some studies suggest certain phytochemicals called flavonoids may inhibit LDL cholesterol production, and this will lead to reduced cholesterol levels, (LDL, the bad cholesterol involved in depositing fat inside your arteries). Flavonoids are found in broccoli, grapefruit, onions, citrus fruit, tea and soybeans. They may also help prevent blood clotting, which can reduce the risk for a heart attack or a stroke. More than 4,000 different flavonoid substances have been found; about 900 are present in human diet.

Other phytochemicals, known as sulfur compounds, are believed to reduce cholesterol production in your body, make platelets in the bloodstream less sticky and even help keep your blood pressure down. Sulfur compounds are found in garlic, leeks and onions.

The cancer connection occurs when phytochemicals work to keep healthy cells in your body from being damaged. Protected cells are less susceptible to an attack by a cancer-causing agent. Ellagic acid, found in grapes, is believed to be one such bodyguard to your cells. Several phytochemicals, such as limonene and caffeic acid, may help to reduce cancer risk by shuttling cancer-causing elements out of your body before they can cause damage.

Where Can You Find Phytochemicals?

Fruits, vegetables, legumes and whole grains are full of phytochemicals. In fact, orange juice has 59 known phytochemicals; broccoli has at least 40, and the herb tarragon has 70. Some of the plant foods you find these chemicals in are:

Cruciferous vegetables

The cruciferous vegetables are one of the most important groups of vegetables from health perspective. The cruciferous vegetables are broccoli, cauliflower, cabbage, brussels sprouts, bok choy and kale. They contain many phytochemcials that have been linked to lower cancer risk, such as glucosinolates, crambene, indole-3-carbinol and isothiocyanates.

Cruciferous vegetables may help to regulate enzymes that defend against cancer. Compounds in cruciferous vegetables can stop the growth of cancer cells in various cells. They help against cancers of breast, endometrium, lung, colon, liver, colon and cervix.

Soy Foods

Soybeans contain several types of phytochemicals. Soy contains several different phytochemicals that have been associated with relief of symptoms of menopause, decreasing bone resorption and decreasing risk of developing certain types of cancers, kidney and cardiovascular diseases. In the United States, we have a range of soy products to choose from. The popularity of soy has grown since the health benefits of soy have become widely known.

What are the Health Benefits of Soy?

Recent research suggests that soy protein and its phytochemical compounds may help to prevent some of the major chronic diseases, including heart disease, cancer and osteoporosis, as well as reduce the symptoms of menopause. Researchers speculate that the synergistic effect of the soluble fiber, phytoestrogens, saponins, phytate and other components may be responsible for the health benefits of soy foods.

What are Some Soy Foods?

Soybeans and soy products, such as soybean oil, soy flour and soy protein, are used extensively in a variety of foods found in a typical supermarket. Soy beverages, tofu, textured soy protein and soy flour can be used as foods or incorporated into many dishes, baked goods and other foods. The soybean and its components give foods sound nutrition, good taste, a long shelf-life and a competitive price. Many of the products available are listed below.

Soy oil accounts for 79% of the edible fats and oils used annually in the United States. Soybean oil contains 61% polyunsaturated and 24% monounsaturated fatty acids, totaling 85% unsaturated fatty acids. Soybean oil is particularly rich in linoleic and linolenic fatty acids. Soybean oil is a chief component of mayonnaise, margarine, salad dressing and vegetable shortening.

Soy flour is the simplest form of soy protein. The flour is produced by grinding and screening defatted soy flakes. Soy flour is about 50% protein. Soy flour can be found in baked goods, noodles, cereals, pancake flour, frozen desserts and instant milk drinks.

Soy isolates are developed through a chemical process in which most of the protein is withdrawn from the defatted flake. The resulting product contains about 90% protein and little moisture. Soy isolates are the chief component of many dairy-like products, including processed cheese, soymilk, infant formula, non-dairy frozen desserts and coffee whiteners. They are used to add texture to meat products and are valued for their emulsifying properties.

Soy concentrates contain about 65% protein and retain most of the bean's dietary fiber. Concentrates also add texture and help foods retain moisture. Surimi, protein drinks, soup bases and gravies contain soy concentrates.

Soybeans, especially the outer hull, are an excellent source of dietary fiber (six grams fiber per one cup cooked). When soybeans are processed, the hull is removed and then processed further to create a fiber additive for breads, cereals and snacks. Soybeans contain both soluble and insoluble fiber. Soluble fiber may help lower serum cholesterol and control blood sugar. Insoluble fiber increases stool bulk, may prevent colon cancer and can help relieve symptoms of some digestive disorders.

Whole soybean foods such as full-fat flour is made from whole soybeans and therefore has the same fat, protein and dietary fiber content as the whole bean. Full-fat flour is used for doughnut mixes, pie crusts, pancake batters and other baked goods.

Soymilk is made from ground soybeans that are mixed with water to form a milk-like liquid. It is consumed by dairy-sensitive individuals as well as strict vegetarians who eat no animal proteins. Soymilk is an excellent source of protein, B-vitamins and iron, and, if fortified, provides adequate calcium. It has low levels of saturated fat and no cholesterol.

Textured soy protein (known commonly as TSP or TVP) is made from defatted soy flour which is compressed and dehydrated into a product rich in protein and fiber, low in fat and sodium. TSP is used as a meat enhancer, extender and substitute.

Mainstays of healthy diets throughout the East for centuries, Asian whole soybean foods are slowly gaining acceptance in the United States as a unique source of nutrition that can help reduce saturated fat in the diet. Whole soybean foods are high in protein, fiber and unsaturated fat, and rich in vitamins and minerals. They also show many anticarcinogenic properties related to the unique benefits of soy isoflavones.

Tofu (soybean curd) is a bland, cheese-like cake formed from soymilk by adding a coagulant (typically calcium sulfate) to the milk to form curds that are then shaped and pressed into cakes. Depending on the coagulant used, tofu is rich in minerals and is an excellent source of high-quality protein, polyunsaturated fats (including linoleic and linolenic acids), B vitamins and iron. Versatile and nutritious, tofu can be used in soups, salads, pastries, sandwiches and spreads. It can also be used as an alternative to yogurt or soft cheese.