Tofu Tofu - health care

Tofu Tofu

Although once only found in Asian food markets, this seemingly bland food can miraculously take on the flavor of its surrounding ingredients making it a highly versatile as well as highly nutritious part of a healthy diet. Tofu can now be found in your local supermarkets throughout the year.

Discovered over 2000 years ago by the Chinese, tofu is sometimes called "the cheese of Asia," because of its physical resemblance to a block of farmer's cheese. Tofu is a highly nutritious, protein-rich food that is made from the curds of soybean milk. Off-white in color, it is usually sold in rectangular blocks. Tofu is a staple in the cuisines of many Asian countries. Tofu is its Japanese name, while in China it is known as doufu.

Food Chart
This chart graphically details the %DV that a serving of Tofu provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Tofu can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Tofu, featuring information over 80 nutrients, can be found under the Food Rating System Chart.

Health Benefits
Description
History
How to Select and Store
How to Enjoy
Individual Concerns
Nutritional Profile
References

Health Benefits
All the good news about tofu being a health-promoting food is true. Tofu is a very good source of protein, specifically soy protein, as well as numerous other nutrients necessary for good health. While a complete review of all the benefits soybeans offer could easily fill a large book, recently there has been controversy as to the extent to which soybeans are a health-promoting food; we address this issue in our Q+A Are there special concerns related to soy foods?

Cardiovascular Benefits of Soy Protein

Research on soy protein in recent years has shown that regular intake of soy protein can help to lower total cholesterol levels by as much as 30%, lower LDL (bad cholesterol) levels by as much as 35-40%, lower triglyceride levels, reduce the tendency of platelets to form blood clots, and possibly even raise levels of HDL (good cholesterol).

All of this sounds very good to people trying to avoid atherosclerosis or diabetic heart disease. High LDL cholesterol levels can lead to a build up of cholesterol deposits in the blood vessels. If these deposits get too large or break, they can cause a heart attack or stroke. Triglycerides are a form in which fats are transported in the blood, so high triglyceride levels, which are often seen in diabetes, can also contribute to the development and growth of these dangerous cholesterol deposits and heart disease. And blood clots can be another major problem for people with heart disease, since they can precipitate a heart attack or stroke. Soy protein, however, can address all of these issues, leading to a greatly reduced risk of heart disease.

Soy for Smooth Sailing through Menopause

Soy has also been shown to be helpful in alleviating the symptoms associated with menopause. Soy foods, like tofu, contain phytoestrogens, specifically the isoflavones, genistein and diadzein. In a woman's body, these compounds can dock at estrogen receptors and act like very, very weak estrogens. During perimenopause, when a woman's estrogen fluctuates, rising to very high levels and then dropping below normal, soy's phytoestrogens can help her maintain balance, blocking out estrogen when levels rise excessively high, plus filling in for estrogen when levels are low. When women's production of natural estrogen drops at menopause, soy's isoflavones may provide just enough estrogenic activity to prevent or reduce uncomfortable symptoms, like hot flashes. The results of intervention trials suggest that soy isoflavones may also promote the resorption of bone and therefore inhibit postmenopausal osteoporosis.

Additionally, most types of tofu are enriched with calcium, which can help prevent the accelerated bone loss for which women are at risk during menopause. Calcium has also been found useful in rheumatoid arthritis, a condition in which calcium may help to reduce the bone loss that can occur as a result of this disease. Tofu is a good source of calcium. Four-ounces supply about 10% of the daily value for calcium and contain only 70-90 calories.

Rich in Minerals for Energy and Antioxidant Protection

Tofu is a very good source of iron, providing 33.8% of the DV for this important mineral in 4 ounces. Iron is primarily used as part of hemoglobin, a molecule essential to energy production since it is responsible for transporting and releasing oxygen throughout the body. But hemoglobin synthesis also relies on copper. Without copper, iron cannot be properly utilized in red blood cells. Fortunately, both minerals are supplied in tofu, which also contain 11.0% of the daily value for copper.

In addition to its role in hemoglobin synthesis, copper may be helpful in reducing the symptoms of rheumatoid arthritis. Copper, along with manganese (yet another trace mineral for which tofu is a very good source), is an essential cofactor of a key oxidative enzyme called superoxide dismutase. Superoxide dismutase disarms free radicals produced within the mitochondria (the energy production factories within our cells). Copper is also necessary for the activity of lysyl oxidase, an enzyme involved in cross-linking collagen and elastin, both of which provide the ground substance and flexibility in blood vessels, bones and joints. Four ounces of tofu supply 34.5% of the DV for manganese.

Want to Be "Buff"? Eat Tofu

Think a meal without meat equals a meal without protein? Think again. Four ounces of tofu provides 9.2 grams of protein, that's 18.3% of the daily value for protein, and it comes virtually free of saturated fat (less than 1 gram), and at a cost of only 86 calories.

Cardiovascular Protection from Omega-3 Fats

Fish aren't the only good source of omega-3 fatty acids. Tofu provides 14.4% of the daily value for these especially beneficial fats in just 4 ounces. Omega-3 fats have been the subject of intensive study by researchers. Omega-3 fatty acids have a broad array of health benefits. Omega-3s help prevent erratic heart rhythms, make blood less likely to clot inside arteries (which is the ultimate cause of most heart attacks), and improve the ratio of good HDL to bad LDL cholesterol. And finally, by reducing inflammation, these essential fats play a role in preventing cholesterol from clogging arteries.

Selenium—An Antioxidant, Anti-Cancer, Anti-Inflammatory Trace Mineral

Several other nutrients in tofu are helpful for other conditions. For example, tofu is a good source of selenium; 4 ounces provide 14.4% of the daily value for this trace mineral. Selenium is needed for the proper function of the antioxidant system, which works to reduce the levels of damaging free radicals in the body. Selenium is a necessary cofactor of one of the body's most important internally produced antioxidants, glutathione peroxidase, and also works with vitamin E in numerous vital antioxidant systems throughout the body. These powerful antioxidant actions make selenium helpful not only against colon cancer by protecting colon cells from cancer-causing toxins, but in decreasing asthma and arthritis symptoms and in the prevention of heart disease. In addition, selenium is involved in DNA repair, yet another way in which adequate intake of this mineral is associated with a reduced risk for cancer.

Description

Tofu is a highly nutritious, protein-rich, delicious food that is made from the curds of soybean milk. Off-white in color, it is usually sold in rectangular blocks. Tofu is a staple in the cuisines of many Asian countries. Tofu is its Japanese name, while in China it is known as doufu.

Tofu is one of the most versatile foods, serving a host of different purposes ranging from salad dressing to dessert to entrée and more. Some of its versatility is owed to its neutral taste, which gives tofu the ability to absorb the flavors of surrounding ingredients. Additionally, tofu comes in a range of consistencies that can suit a variety of different recipes. Tofu is available in either the traditional Chinese form or the silken Japanese form, with the latter having a smoother, custard-like texture. Both forms can be found in soft, firm or extra-firm textures.

The scientific name for soybean, from which tofu is made, is Glycine max.

History

Tofu originated in China about 2000 yearsw ago. While the details of its discovery are uncertain, legend has it that it was discovered by accident when a Chinese cook added the seaweed nigari to a pot of soybean milk, causing it to curdle; the result was tofu.

Tofu was introduced into Japan in the 8th century, where it was originally known as "okabe," but was not called "tofu" until the 15th century. While serving as a traditionally made dish, tofu did not gain its great widespread popularity in Japan until the 17th century.

Tofu's popularity in the West has mirrored the increasing interest in healthier foods. First gaining more widespread attention during the 1960s, tofu has been skyrocketing in popularity ever since research has begun to reveal the many significant benefits this nutrient-rich, plant-based food can provide.

How to Select and Store

Tofu is available refrigerated in individual packages or in bulk, or non-refrigerated in aseptically sealed containers. Packaged tofu should feature expiration dates, which you can use as a guideline for how long of a shelflife it will have.. Tofu varies in texture from soft to firm to extra-firm. Soft tofu has a smoother texture and is therefore better suited for salad dressings, sauces and desserts, while firm and extra-firm tofu are best for baking, stir-frying and grilling.

While aseptically packaged tofu need not be refrigerated until it is opened, all other forms of tofu should be refrigerated in their container. Once their packages are open, all types should be rinsed well, kept in a container covered with water, and placed in the refrigerator. Changing the water daily will help keep the tofu fresh for up to one week.

Tofu can also be frozen in its original packaging and will keep this way for up to five months. This process will actually alter its texture and color, making it more spongy and absorbent, and more yellowish in color. This change in physical properties is actually very suitable for certain recipe preparations.

If you are selecting tofu on the basis of fat content, the firmer tofus are usually the highest in fat, and the softest tofus, often called silky or silken, are the lowest.

If you are looking for tofu with a high calcium content, look for products that specifically say "calcium-precipitated" on the label or that include calcium sulfate in their ingredient list. This method of tofu manufacturing uses calcium to help coagulate the soy milk.

How to Enjoy

For some of our favorite recipes, click Recipes.

A Few Quick Serving Ideas:

Blend together soft tofu, olive oil, garlic and lemon juice to make a tofu aoli dip.

Scramble soft tofu together with your favorite vegetables and the spice turmeric to give it a yellow "egg-like" coloring. This delicious dish can be served as is or can be used as the basis for "tofu rancheros" by being wrapped in a tortilla and served with black beans and salsa.

Healthy Stir-Fry firm tofu with your favorite vegetables and seasonings.

Blend soft tofu with your favorite fruits (and honey or other natural sweeteners to taste) in a blender or food processor and serve for breakfast or dessert.

Add cubes of tofu to miso soup.

Individual Concerns

Allergic Reactions to Tofu

Although allergic reactions can occur to virtually any food, research studies on food allergy consistently report more problems with some foods than with others. It's important to realize that the frequency of problems varies from country to country and can change significantly along with changes in the food supply or with other manufacturing practices. For example, in several part of the world, including Canada, Japan, and Israel, sesame seed allergy has risen to a level of major concern over the past 10 years.

In the United States, beginning in 2004 with the passage of the Food Allergen Labeling and Consumer Protection Act (FALCPA), food labels have been required to identify the presence of any major food allergens. Since 90% of food allergies in the U.S. have been associated with 8 food types as reported by the U.S. Centers for Disease Control, it is these 8 food types that are considered to be major food allergens in the U.S. and require identification on food labels. The 8 food types classified as major allergens are as follows: (1) wheat, (2) cow's milk, (3) hen's eggs, (4) fish, (5) crustacean shellfish (including shrimp, prawns, lobster and crab); (6) tree nuts (including cashews, almonds, walnuts, pecans, pistachios, Brazil nuts, hazelnuts and chestnuts); (7) peanuts; and ( soy foods.

These foods do not need to be eaten in their pure, isolated form in order to trigger an adverse reaction. For example, yogurt made from cow's milk is also a common allergenic food, even though the cow's milk has been processed and fermented in order to make the yogurt. Ice cream made from cow's milk would be an equally good example.

Food allergy symptoms may sometimes be immediate and specific, and can include skin rash, hives, itching, and eczema; swelling of the lips, tongue, or throat; tingling in the mouth; wheezing or nasal congestion; trouble breathing; and dizziness or lightheadedness. But food allergy symptoms may also be much more general and delayed, and can include fatigue, depression, chronic headache, chronic bowel problems (such as diarrhea or constipation), and insomnia. Because most food allergy symptoms can be caused by a variety of other health problems, it is good practice to seek the help of a healthcare provider when evaluating the role of food allergies in your health.

Tofu and Oxalates

Soybeans, and foods made from them like tofu, are among a small number of foods that contain measurable amounts of oxalates, naturally-occurring substances found in plants, animals, and human beings. When oxalates become too concentrated in body fluids, they can crystallize and cause health problems. For this reason, individuals with already existing and untreated kidney or gallbladder problems may want to avoid eating soybean-based products like tofu. Laboratory studies have shown that oxalates may also interfere with absorption of calcium from the body. Yet, in every peer-reviewed research study we've seen, the ability of oxalates to lower calcium absorption is relatively small and definitely does not outweigh the ability of oxalate-containing foods to contribute calcium to the meal plan. If your digestive tract is healthy, and you do a good job of chewing and relaxing while you enjoy your meals, you will get significant benefits—including absorption of calcium—from calcium-rich foods plant foods that also contain oxalic acid. Ordinarily, a healthcare practitioner would not discourage a person focused on ensuring that they are meeting their calcium requirements from eating these nutrient-rich foods because of their oxalate content. For more on this subject, please see "Can you tell me what oxalates are and in which foods they can be found?"

Soybean-based Foods and Genetically Modified Organisms (GMOs)

A large percentage of the conventionally grown soybeans in the United States come from genetically modified (GM) seeds. If you are looking your exposure to GM foods, choose organically grown soybeans (and foods such as tofu, tempeh and miso made from it), since the current USDA organic regulations prohibit the use of GM seeds for growing foods to be labeled as organically grown. A wide assortment of processed food contain soy-based ingredients (such as soy protein and hydrolyzed vegetable protein); look for the organic version of these items in your foods and/or look for foods that note that they do not contain any genetically modified ingredients (sometimes this is noted on the packaged as "GMO-free"). For more on this subject, see this Q+A.

Nutritional Profile

Tofu is a very good source of manganesem, iron and protein. In addition, tofu is a good source of selenium, omega-3 fatty acids, phosphorus, copper, calcium and magnesium.

For an in-depth nutritional profile click here: Tofu.

In-Depth Nutritional Profile
In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Tofu is also available. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more.

Introduction to Food Rating System Chart
In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the nutrients for which this food is either an excellent, very good, or good source (below the chart you will find a table that explains these qualifications). If a nutrient is not listed in the chart, it does not necessarily mean that the food doesn't contain it. It simply means that the nutrient is not provided in a sufficient amount or concentration to meet our rating criteria. (To view this food's in-depth nutritional profile that includes values for dozens of nutrients - not just the ones rated as excellent, very good, or good - please use the link below the chart.) To read this chart accurately, you'll need to glance up in the top left corner where you will find the name of the food and the serving size we used to calculate the food's nutrient composition. This serving size will tell you how much of the food you need to eat to obtain the amount of nutrients found in the chart. Now, returning to the chart itself, you can look next to the nutrient name in order to find the nutrient amount it offers, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling." Read more background information and details of our rating system.

Tofu, raw
4.00 oz-wt
113.40 grams
86.18 calories
Nutrient Amount DV
(%) Nutrient
Density World's Healthiest
Foods Rating
tryptophan 0.14 g 43.8 9.1 excellent
manganese 0.69 mg 34.5 7.2 very good
iron 6.08 mg 33.8 7.1 very good
protein 9.16 g 18.3 3.8 very good
omega 3 fatty acids 0.36 g 15.0 3.1 good
selenium 10.09 mcg 14.4 3.0 good
copper 0.22 mg 11.0 2.3 good
phosphorus 110.00 mg 11.0 2.3 good
calcium 100.00 mg 10.0 2.1 good
magnesium 34.02 mg 8.5 1.8 good
World's Healthiest
Foods Rating Rule
excellent DV>=75% OR Density>=7.6 AND DV>=10%
very good DV>=50% OR Density>=3.4 AND DV>=5%
good DV>=25% OR Density>=1.5 AND DV>=2.5%

In-Depth Nutritional Profile for Tofu

References

Ensminger AH, Esminger M. K. J. e. al. Food for Health: A Nutrition Encyclopedia. Clovis, California: Pegus Press; 1986 1986. PMID:15210.
Fortin, Francois, Editorial Director. The Visual Foods Encyclopedia. Macmillan, New York 1996.
Kritz-Silverstein D, Goodman-Gruen DL. Usual dietary isoflavone intake, bone mineral density, and bone metabolism in postmenopausal women. J Womens Health Gend Based Med 2002 Jan-Feb;11(1):69-78 2002.
Wood, Rebecca. The Whole Foods Encyclopedia. New York, NY: Prentice-Hall Press; 1988 1988. PMID:15220.
Yamori Y, Moriguchi EH, Teramoto T et al. Soybean isoflavones reduce postmenopausal bone resorption in female Japanese immigrants in Brazil: a ten-week study. J Am Coll Nutr 2002 Dec;21(6):560-3 2002.