Although not a common item in most households in the United States, tempeh, with its distinctively nutty taste and nougat-like texture, is increasing in popularity. It easily absorbs the flavors of the other foods with which it is cooked making it adaptable to many types of dishes. Tempeh can be found in health food stores and specialty markets throughout the year.
Tempeh has been a staple in Indonesia for over 2000 years. It is a highly nutritious fermented food traditionally made from soybeans and its high protein content makes it a wonderful substitute for meat. It is typically made by cooking and dehulling soybeans, inoculating them with a culturing agent (like Rhizopus oligosporus), and then incubating the innoculated product overnight until it forms a solid cake.
A food made from fermented soybeans, tempeh provides not only the protein found in soybeans but their many other health benefits as well. The soybean is the most widely grown and utilized legume in the world, with the U.S. being responsible for more than 50% of the world’s production of this important food. Soy is one the most widely researched, health-promoting foods around. Soy’s key benefits are related to its excellent protein content, its high levels of essential fatty acids, numerous vitamins and minerals, its isoflavones, and its fiber. While a complete review of all the benefits soy foods 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?
Soybeans are regarded as equal in protein quality to animal foods. Just 4 ounces of tempeh provides 41% of the Daily Value (DV) for protein for less than 225 calories and only 3.9 grams of saturated fat. Plus, the soy protein in tempeh tends to lower cholesterol levels, while consuming protein from animal sources tends to raise them, since they also include saturated fat and cholesterol.
In addition to healthy protein, some of tempeh’s nutritional high points include:
Riboflavin: 4 ounces of tempeh provides 24% of the DV for this B-vitamin. A nutrient essential for the transfer reactions that occur to produce energy in the mitochondria, riboflavin is also a cofactor in the regeneration of one of the liver’s most important detoxification enzymes, glutathione.
Magnesium: Tempeh also provides 22% of the DV for Nature’s blood vessel relaxant, magnesium, in just 4 ounces. In addition to its beneficial role in the cardiovascular system, magnesium plays an essential role in more than 300 enzymatic reactions, including those that control protein synthesis and energy production.
Manganese and Copper: That same 4 ounces of tempeh will give you 73% of the DV for manganese and 31% of the DV for copper. These two trace minerals serve numerous physiological functions including being cofactors for the antioxidant enzyme superoxide dismutase.
Soy protein has been found in recent years to be excellent for a number of different conditions, one of the most important ones being heart disease. Soy protein has been shown in some studies to be able to lower total cholesterol levels by 30% and to lower LDL, or “bad” cholesterol, levels by as much as 35-40%. This is important because high levels of cholesterol, especially LDL cholesterol, tend to become deposited into the walls of blood vessels, forming hard plaques. If these plaques grow too large or break, they can cause a heart attack or stroke.
Some studies have even shown that soy protein may be able to raise HDL cholesterol levels. HDL cholesterol travels through the body collecting the cholesterol that has been deposited in the arteries, so it can be taken away and removed by the liver. One of the main goals of atherosclerosis treatment and prevention, therefore, is to lower LDL cholesterol levels while raising HDL levels. And soy is one food that may be able to do both at once.
In addition, soy foods like tempeh are rich in dietary fiber. When eaten, the fiber in tempeh binds to fats and cholesterol in food, so less is absorbed. In addition, tempeh’s fiber binds to bile salts and removes them from the body. Since the liver gets rid of cholesterol by transforming it into bile salts, their removal by fiber forces the liver to use more cholesterol to form more bile salts, leading to lower cholesterol levels overall.
Another condition for which tempeh can be very beneficial is diabetes, particularly type 2 diabetes. The protein in tempeh is excellent for diabetic patients, who tend to have problems with animal sources of protein. The protein and fiber in tempeh can also prevent high blood sugar levels and help in keeping blood sugar levels under control. Some diabetics even find that the effects of soy foods, such as tempeh, and other legumes on blood sugar are so profound that they need to monitor their new blood sugar levels and adjust their medications accordingly. Of course, all of this should only be done under the supervision of a doctor. Diabetes patients are especially susceptible to atherosclerosis and heart disease, which is the number one killer of persons with diabetes. Keeping cholesterol levels low with soy foods may be useful for preventing these heart problems. In addition, soy foods have been shown to lower high triglyceride levels. Triglyceride levels tend to be high in diabetic patients, and high triglyceride levels are another factor of diabetics’ increased risk for heart disease.
The fiber in tempeh also provides preventative therapy for several other conditions. Fiber is able to bind to cancer-causing toxins and remove them from the body, so they can’t damage colon cells. Tempeh, which is made from high-fiber soybeans, may therefore be able to help reduce the risk of colon cancer. As a matter of fact, in areas of the world where soy foods are eaten regularly, rates of colon cancer, as well as some other cancers, including breast cancer, tend to be low.
One of the more popular uses of soy foods lately has been in the treatment of menopausal symptoms. Soybeans contain active compounds called isoflavones that act like very weak estrogens in the body. These phytoestrogens bind to estrogen receptors and may provide enough stimulation to help eliminate some of the uncomfortable symptoms that occur when natural estrogen levels decline. Studies have shown that women who consume soy foods report a significant reduction in the amount of hot flashes that they experience. There is also some evidence that soy foods may even be able to help reduce the bone loss that typically occurs after menopause. And as women’s risk for heart disease significantly increases at menopause, soy foods’ numerous beneficial cardiovascular effects make tempeh a particularly excellent choice for frequent consumption as menopause approaches.
In epidemiological studies, genistein, a naturally occuring isoflavone found chiefly in soy foods, has been consistently linked to lower incidence of prostate cancer. A recent study of human prostate cancer cells demonstrated some of the mechanisms behind genistein’s anti-prostate cancer effects. Genistein not only induced chemicals that block cell cycling, thus preventing the proliferation of cancerous cells in the prostate, but at high concentrations actually induced apoptosis, the self-destruct sequence the body uses to eliminate worn out or abnormal cells.
Another study looked at the antioxidant effects of these isoflavones in soy, and found that genistein protected cells in healthy men from an increase in free radical production by inhibiting the activation of an important inflammatory agent called NF-kappaB and by decreasing levels of DNA adducts (a marker of DNA damage).
For many years it was only possible to find tempeh in natural foods and Asian stores. Yet, with the growing demand for soy foods, tempeh is now becoming more and more available in supermarkets throughout the country. Depending upon the store, tempeh may either be kept in the refrigerated or freezer section. In addition to plain soy tempeh, oftentimes varieties that include grains or vegetables are available.
Look for tempeh that is covered with a thin whitish bloom. While it may have a few black or grayish spots, it should have no evidence of pink, yellow or blue coloration as this indicates that it has become overly fermented.
Refrigerated tempeh can keep in the refrigerator for up to ten days. If you do not consume the whole package of tempeh at one time, wrap it well and place it back in the refrigerator. Tempeh will keep fresh for several months in the freezer.