Benefits and side effects of tofu

Tofu can be prepared on a small scale in more traditional kitchens but is also more widely produced and readily sold in markets. Irrespective of where the tofu is produced, the key steps to tofu making are the same. The main principles of preparing tofu are:

• Preparation of soy milk from soybeans: Soybeans are cleaned, soaked, boiled, grinders and then filtered to produce soy milk.
• Coagulation of soy milk to form bean curd: Much like curdling animal milk to create dairy-based cheeses, tofu is created by coagulating soy milk. A coagulant is added to the soy milk that solidifies it in small chunks or curds. 
• Pressing of soy milk curds to form tofu blocks or cakes: The curdled soy milk is removed from the bean curd and the bean curd is pressed into blocks or cakes. By removing the required amount of extra fluid desired firmness of tofu can be achieved.

Traditionally, tofu is classified on the basis of its consistency of firmness. These include:

• Silken tofu: This is the softest type of tofu as it is made without curdling the soy milk. The consistency of silken tofu is akin to cream and it is almost jelly-like on the tongue. Silken tofu is a good vegan substitute for baking in addition to more traditional recipes. When using silken tofu, there is no need to press it, simply drain the extra fluid and proceed. 
• Firm tofu or block tofu: This type of tofu holds its shape better and is pressed into blocks as part of its processing. Block tofu too comes in varying degrees of firmness that depends on its water content and how long it has been pressed for. Types of block tofu include:
  • Soft block tofu
  • Medium block tofu
  • Firm block tofu
  • Extra-firm tofu

Soft and medium tofu is more crumbly and better suited for recipes that do not require it to hold its shape. Firm and extra-firm tofu has very little fluid content in comparison to the former two and can hold its shape even at high temperatures, making it the perfect paneer or meat substitute in any dish. 

• 3. Flavoured tofu: Tofu on its own is quite bland and picks up the flavours of the recipe very well. Some preparations of flavoured packaged tofu are also available in the market.
  • Smoked tofu: Extra firm tofu is soaked in tea leaves that impart to it a rich smoky flavour.
  • Seasoned tofu: Tofu is packaged with marinades like soy sauce, garlic or sesame to pack a greater punch of flavour when cooking.
  • Fried tofu: Fried pre-packaged tofu absorbs sauces, seasoning and gravies very well.

Nowadays, many new types of tofu are being produced that incorporate spices, nuts or vegetables within the pressed tofu block itself. Masala tofu is easily available in many parts of India.

Tofu is an excellent source of protein and provides adequate daily energy to the body while being comparatively low in fats. Although it only contains modest amounts of vitamins, it is a good source of minerals like iron, calcium, manganese and copper. Thus, adding tofu to the daily diet can be beneficial for those suffering from iron deficiency anemia and prevents osteoporosis as well. Tofu, like other soy-based products, is rich in phytoestrogens and isoflavones that have estrogen-like activity in the body. Estrogen is a naturally occurring sex hormone in the body, in larger quantities in females and smaller in males. Phytoestrogens, present in soy proteins, are plant estrogens also responsible for lowering the “bad cholesterol” levels (low-density lipoproteins and triglycerides) in the body. The Food and Drug Administration (FDA, USA) has even stated that “25 grams of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease". While the health benefits of plant estrogens are manifold, excessive prolonged consumption can pose health risks as well.

100 grams of uncooked soy tofu contains: 

• Energy: 76 kcal
• Total fat: 4.8g
• Saturated fat: 0.7g
• Sodium: 7mg
• Total carbohydrates: 1.9g
• Dietary fiber: 0.3g
• Sugar: 0.6g
• Protein: 8.1g
• Calcium: 350mg
• Potassium: 121 mg
• Iron: 5.36mg

Tofu is an important way to boost one’s nutrition through diet, owing to its high protein and low fat content along with natural plant oestrogens, isoflavones and minerals like iron, calcium, manganese and copper. Some benefits of eating tofu regularly include the following:

• Tofu is an important source of plant-based protein, especially for vegetarians and vegans. Protein is needed by the body to build, grow and repair itself and its connective tissue components like hair, skin, nails, bones, muscles and more.
• It is a good source of energy while being comparatively low in fat. About 100 grams of regular uncooked tofu contains 4.8 grams of fat, whereas 100 grams of regular uncooked paneer contains 22 grams of fat. Therefore, tofu is apt for people trying to reduce weight, control blood lipids or cut back on fat consumption.
• Being a good source of iron, a 100 gram serving of tofu fulfils more than one-third of the daily recommended iron requirement. It can be added to the diet for people suffering from iron deficiency anemia.
• Phytoestrogens are plant oestrogens present in soy protein that exert a beneficial effect on the blood cholesterol levels. Although they have not been shown to increase “good cholesterol” (high-density lipoprotein) levels, they are known to reduce “bad cholesterol” (low-density lipoproteins and triglycerides) levels.
• The cardioprotective effect of phytoestrogens of tofu stems from the lowered cholesterol levels and less atherosclerotic plaque buildup. At least 25 grams of tofu, or other soy products, should be consumed daily for a benefit to be observed.
• Isoflavones present in the soy protein of tofu have an antioxidant action on cells and can help prevent free radical damage and potential cancer development. Earlier, it was assumed that isoflavones, similar in chemical structure to estrogen, could induce breast cancer but now the consensus is that moderate consumption of soy products can have a protective effect against breast and prostate cancer.
• The fall in blood estrogen levels of women undergoing menopause leads to many uncomfortable symptoms like irregular menstrual (vaginal) bleeding, hot flashes, mood swings, weight gain, vaginal dryness and frequent urinary tract infections. By naturally boosting the estrogen levels in the body through diet, some of these symptoms can be managed to a certain extent.
• It is good for patients with chronic kidney disease and type 2 diabetes mellitus as soy protein in tofu promotes less excretion of protein through urine.
• Tofu is made from soybeans, which are a type of legume, and therefore naturally gluten-free. Tofu is a good addition to the diet for people with gluten sensitivity or celiac disease.
• Tofu has been shown to prevent age-related brain diseases and preserve cognitive function when consumed daily.
• Although not as rich in calcium as paneer, tofu is still a good source of the mineral. Adding calcium-rich foods to the diet is important to build calcium stores to boost bone and teeth health and prevent osteoporosis.
• Tofu also contains selenium, a mineral with a key role in the nourishment of hair.

Although tofu is considered a superfood for many substantial reasons, excessive and prolonged consumption of soy products is associated with its own set of health risks. Possible side effects of eating too much tofu include: 

• Breast cancer: Some evidence suggests that eating too much tofu, and other soy products rich in estrogens, can increase the risk of estrogen receptor positive (ER+) breast cancer. Moderate consumption of tofu, for example, two servings a day, is not thought to be harmful.
• Feminisation or reduction of fertility in males: Too much estrogen in the male body can cause mild feminisation with the development of male breasts (gynecomastia), loss of hair or reduction of fertility. 
• Should not be eaten when on Monoamine Oxidase Inhibitors (MAOI): MAOIs are drugs used to treat mood disorders and Parkinson’s disease that prevent the breakdown of an amino acid called tyramine, which is present in soy products, in the body. High tyramine levels can cause dangerous spikes in blood pressure.
• Excessively processed tofu products like tofu sausages may contain a lot of added salt or additives and should be avoided.

Over the last two thousand years, tofu has continued to remain an integral part of Asian cuisine. Much more recently, it has also gained notoriety in the West and cuisines of other cultures, including those of the Indian subcontinent. Tofu is not only a delicious meat substitute for those who are following a plant-based or vegan diet, but it is also a very good source of daily protein and energy. Although tofu can even be enjoyed after simply steaming, some more tasty and healthy recipes using tofu include:

• Stir-fries: The easiest way to incorporate tofu in one's diet would be by cutting it up in small cubes, adding some chopped vegetables and lightly tossing it in a pan with seasoning of one's choice.
• Soups: Tofu can be added to any soup – a popular choice is miso soup, which has its own host of health benefits. The tofu does not need to be cooked separately as the steam from the soup will cook it. 
• Tofu scramble: A vegan substitute for the popular breakfast dish scrambled eggs or egg bhurji can be made using tofu and seasoning well.
• Salad: Uncooked or stir-fried tofu can be added to a salad. Although it may sound unusual, tofu can be eaten raw. As tofu is cooked in the various steps of processing, it is not considered uncooked.
• Popular Indian paneer recipes: Firm or extra firm tofu can be used as a substitute for paneer in every recipe that usually calls for paneer. Tofu is prepared the same way as paneer; however, softer varieties of tofu may need to be pressed first to remove excess water content. Tofu should be salted and seasoned well as it does not have a taste of its own.
• Baking: Silken tofu and soft tofu are popular agents added to confectionery and baked goods owing to their soft consistency and creamy texture.

Moderate amounts of tofu in the daily diet of those without a history of allergy to other legumes or soy can be beneficial, especially for vegetarians and vegans, by increasing protein intake and reducing cholesterol levels. Excessive tofu consumption is not recommended.