Tofu is one of those foods that sparks debate. Some can't rave enough about its versatility and health benefits. Others think it is a genetically-modified poison to be avoided at all costs. This may leave you wondering whether tofu should be a part of your diet or not.
This article takes a detailed look at tofu and its health effects, both good and bad.
What is Tofu?
Tofu is a food made of condensed soy milk that is pressed into solid white blocks. It originated in China and the process is quite similar to how cheese is made.
Rumor has it that a Chinese cook discovered tofu more than 2,000 years ago by accidentally mixing a batch of fresh soy milk with nigari.
Nigari is what remains when salt is extracted from seawater. It is a mineral-rich coagulant used to help tofu solidify and keep its form.
This is what fresh tofu looks like:
Most of the world's soybeans are currently grown in the U.S. and a very large proportion is genetically modified.
Although genetically modified foods are controversial, research has so far not found them to be harmful to human health (1).
However, if you're worried about it, simply opt for non-GMO, organic tofu brands.
Bottom Line: Tofu is made from condensed soy milk, in a process similar to how cheese is made. Whether made from GMO soybeans or not, tofu is generally considered safe for human consumption.
Tofu Contains Many Nutrients
Tofu is high in protein and contains all the essential amino acids your body needs. It also contains fats, carbs and a wide variety of vitamins and minerals.
One 3.5-oz (100-gram) serving of tofu contains:
- Protein: 8 grams.
- Carbs: 2 grams.
- Fiber: 1 gram.
- Fat: 4 grams.
- Manganese: 31 percent of the RDI.
- Calcium: 20 percent of the RDI.
- Selenium: 14 percent of the RDI.
- Phosphorus: 12 percent of the RDI.
- Copper: 11 percent of the RDI.
- Magnesium: 9 percent of the RDI.
- Iron: 9 percent of the RDI.
- Zinc: 6 percent of the RDI.
This comes with only 70 total calories, which makes tofu a highly nutrient-dense food.
However, the micronutrient content of tofu can vary, depending on the coagulant used to make it. Nigari adds more magnesium, while precipitated calcium increases the calcium content.
Bottom Line: Tofu is low in calories, but high in protein and fat. It also contains many important vitamins and minerals.
Tofu Also Contains Antinutrients
Like most plant foods, tofu contains several antinutrients.
These include:
- Phytates: Phytates can reduce the absorption of minerals such as calcium, zinc and iron.
- Lectins: Lectins are proteins that can cause nausea and bloating when uncooked, improperly cooked or eaten in excess.
However, soaking or cooking soybeans can inactivate or eliminate some of these antinutrients.
Sprouting soybeans before making tofu reduces phytates by up to 56 percent and trypsin inhibitors by up to 81 percent, while also increasing protein content by up to 13 percent (2).
Fermentation can also reduce anti-nutrients. For this reason, make sure to add fermented probiotic soy foods to your diet, such as miso, tempeh, tamari or natto.
Bottom Line: Tofu contains antinutrients like trypsin inhibitors, phytates and lectins. It is possible to degrade these antinutrients, which increases the nutritional value of tofu.
Tofu Contains Beneficial Isoflavones
Soybeans contain natural plant compounds called isoflavones.
These isoflavones function as phytoestrogens, meaning that they can attach to and activate estrogen receptors in the body.
This produces effects similar to the hormone estrogen, although they are weaker.
The two main isoflavones in soy are genistein and daidzein and tofu contains 20.2–24.7 mg of isoflavones per 3.5-oz (100-gram) serving (3).
Many of the health benefits of tofu are attributed to the high isoflavone content.
Bottom Line: All soy-based products contain isoflavones, which are believed to have various health benefits.
Tofu May Reduce the Risk of Heart Disease
Only a few studies specifically look at tofu's effects on heart health.
However, research has shown that a high intake of legumes, including soy, is linked to lower rates of heart disease (4).
We also know that soy isoflavones can reduce blood vessel inflammation and improve their elasticity (5).
One study found that supplementing with 80 mg of isoflavones per day for 12 weeks improved blood flow by 68 percent in patients who were at risk of stroke (6).
Taking 50 grams of soy protein per day is also associated with improved blood fats and an estimated 10 percent lower risk of heart disease (7).
What's more, in post-menopausal women, high soy isoflavone intake was linked to several heart protective factors. These included improvements to body mass index, waist circumference, fasting insulin and HDL cholesterol (8).
Finally, tofu also contains saponins, compounds thought to have protective effects on heart health (9).
Animal studies have shown that saponins improve blood cholesterol and increase the disposal of bile acids, both of which can help lower heart disease risk (10).
Bottom Line: Whole soy foods like tofu can improve several markers of heart health. This may lead to a reduced risk of heart disease.
Tofu is Linked to Reduced Risk of Some Cancers
Studies have looked into the effects of tofu on breast, prostate and digestive system cancers.
Tofu and Breast Cancer
Research shows that women who eat soy products at least once a week have a 48–56 percent lower risk of breast cancer (11, 12).
This protective effect is thought to come from isoflavones, which have also been shown to positively influence the menstrual cycle and blood estrogen levels (13, 14).
It seems that exposure to soy during childhood and adolescence may be most protective, but that's not to say that intake later in life is not beneficial (15).
In fact, research shows that women who ate soy products at least once a week throughout adolescence and adulthood had a 24 percent lower risk of developing breast cancer, compared to those who ate soy during adolescence alone (16).
One often-heard criticism of tofu and other soy products is that they may increase breast cancer risk. However, a two-year study in which post-menopausal women consumed two servings of soy per day failed to find an increased risk (17).
Other studies report similar findings, including a review of 174 studies, which found no link between soy isoflavones and increased risk of breast cancer (18, 19, 20).
Tofu and Cancers of the Digestive System
One study observed that higher intakes of tofu were linked to a 61 percent lower risk of stomach cancer in men (21).
Interestingly, a second study reported a 59 percent lower risk in women (22).
What's more, a recent review of 633,476 participants linked higher soy intake to a 7 percent lower risk of cancer of the digestive system (23).
Tofu and Prostate Cancer
Two review studies found that men consuming higher amounts of soy, especially tofu, had a 32–51 percent lower risk of developing prostate cancer (24, 25).
A third review agrees with this, but adds that the beneficial effects of isoflavones may depend on the amount consumed and type of gut bacteria present (26).
Bottom Line: Research indicates that soy has a protective effect against breast, digestive and prostate cancers.
Tofu May Reduce the Risk of Diabetes
Over the past 10 years, several cell and animal studies have shown that soy isoflavones can have benefits for blood sugar control (27, 28).
In one study of healthy post-menopausal women, 100 mg of soy isoflavones per day reduced blood sugar levels by 15 percent and insulin levels by 23 percent (29).
For diabetic post-menopausal women, supplementing with 30 grams of isolated soy protein lowered fasting insulin levels by 8.1 percent, insulin resistance by 6.5 percent, LDL cholesterol by 7.1 percent and total cholesterol by 4.1 percent (30).
In another study, taking isoflavones each day for a year improved insulin sensitivity and blood fats, while reducing the risk of heart disease (31).
However, these findings are not universal. A recent review of 24 human studies found that intact soy protein—as opposed to isoflavone supplements or protein extracts—was more likely to lower blood sugar (32, 33).
Bottom Line: Tofu may have positive effects on blood sugar control, but more studies are needed to confirm this link.
Other Potential Health Benefits of Tofu
Due to its high isoflavone content, tofu may also have benefits for:
- Bone health: Scientific data suggests that 80 mg of soy isoflavones per day may reduce bone loss, especially in early menopause (34, 35).
- Brain function: Soy isoflavones may have a positive influence on memory and brain function, especially for women over 65 (36).
- Menopause symptoms: Soy isoflavones may help reduce hot flashes. However, not all studies agree (37, 38, 39, 40, 41).
- Skin elasticity: Taking 40 mg of soy isoflavones per day significantly reduced wrinkles and improved skin elasticity after 8–12 weeks (42).
- Weight loss: In one study, taking soy isoflavones for 8–52 weeks resulted in an average weight loss of 10 lbs (4.5 kg) more than a control group (43).
Bottom Line: Due to its high isoflavone content, tofu may have benefits for a variety of health conditions. However, more research is needed.
Tofu May Cause Problems for Some People
Eating tofu and other soy foods every day is generally considered to be safe. That being said, you may want to moderate your intake if you have:
- Kidney or gallbladder stones: Tofu contains a good amount of oxalates, which may worsen oxalate-containing kidney or gallbladder stones.
- Breast tumors: Due to tofu's weak hormonal effects, some doctors tell women with estrogen-sensitive breast tumors to limit their soy intake.
- Thyroid issues: Some professionals also advise individuals with poor thyroid function to avoid tofu due to its goitrogen content.
However, not all researchers agree. Some even say that consuming soy foods like tofu can benefit people with kidney stones (44).
In addition, a recent report from the European Food Safety Authority (EFSA) concluded that soy and soy isoflavones pose no concerns for breast and uterine cancers or thyroid function (45).
Nevertheless, researchers agree that infants should not be exposed to soy isoflavones, which may disrupt the development of reproductive organs (26, 46).
Although this has not been studied well in humans, some animal studies suggest that high amounts of soy may interfere with fertility (47, 48).
Bottom Line: Eating tofu is safe for most people. If you're worried about negative health effects, then double-check with your healthcare provider.
How to Select Tofu or Make Your Own
Tofu can be purchased in bulk or individual packages, refrigerated or not.
You can also find it dehydrated, freeze-dried, jarred or canned.
Generally, not a lot of processing is necessary to make tofu, so choose varieties that have short nutrition labels.
You can expect to see ingredients like soybeans, water, coagulants (such as calcium sulfate, magnesium chloride or delta gluconolactone) and maybe some seasoning.
Once opened, tofu blocks need to be rinsed prior to being used.
Leftovers can be stored in the refrigerator, covered with water. Stored this way, tofu can be kept for up to one week—just make sure you change the water often.
Tofu can also be frozen, in its original package, for up to five months.
Finally, making your own tofu is also a possibility. All you need are soybeans, lemon and water. If you'd like to give it a try, check out this simple video:
Bottom Line: Tofu can be found in a variety of shapes and forms. Homemade tofu is also surprisingly easy to make.
Tofu is a Healthy Food
Tofu is high in protein and many healthy nutrients.
Eating tofu may protect against a variety of health conditions, such as heart disease, diabetes and even certain cancers.
This article was reposted from our media associate Authority Nutrition.
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In a new study, my colleagues Anisha Patel, Francesca Weaks and I estimate that approximately 61.4 million people in the U.S. did not drink their tap water as of 2017-2018. Our research, which was released in preprint format on April 8, 2021, and has not yet been peer reviewed, found that this number has grown sharply in the past several years.
Other research has shown that about 2 million Americans don't have access to clean water. Taking that into account, our findings suggest that about 59 million people have tap water access from either their municipality or private wells or cisterns, but don't drink it. While some may have contaminated water, others may be avoiding water that's actually safe.
Water insecurity is an underrecognized but growing problem in the U.S. Tap water distrust is part of the problem. And it's critical to understand what drives it, because people who don't trust their tap water shift to more expensive and often less healthy options, like bottled water or sugary drinks.
I'm a human biologist and have studied water and health for the past decade in places as diverse as Lowland Bolivia and northern Kenya. Now I run the Water, Health, and Nutrition Laboratory at Pennsylvania State University. To understand water issues, I talk to people and use large datasets to see whether a problem is unique or widespread, and stable or growing.
An Epidemic of Distrust
According to our research, there's a growing epidemic of tap water distrust and disuse in the U.S. In a 2020 study, anthropologist Sera Young and I found that tap water avoidance was declining before the Flint water crisis that began in 2014. In 2015-2016, however, it started to increase again for children.
Our new study found that in 2017-2018, the number of Americans who didn't drink tap water increased at an alarmingly high rate, particularly for Black and Hispanic adults and children. Since 2013-2014 – just before the Flint water crisis began – the prevalence of adults who do not drink their tap water has increased by 40%. Among children, not consuming tap has risen by 63%.
To calculate this change, we used data from the National Health and Nutrition Examination Survey, a nationally representative survey that releases data in two-year cycles. Sampling weights that use demographic characteristics ensure that the people being sampled are representative of the broader U.S. population.
Racial Disparities in Tap Water Consumption
Communities of color have long experienced environmental injustice across the U.S. Black, Hispanic and Native American residents are more likely to live in environmentally disadvantaged neighborhoods, with exposure to water that violates quality standards.
Our findings reflect these experiences. We calculated that Black and Hispanic children and adults are two to three times more likely to report not drinking their tap water than members of white households. In 2017-2018, roughly 3 out of 10 Black adults and children and nearly 4 of 10 Hispanic adults and children didn't drink their tap water. Approximately 2 of 10 Asian Americans didn't drink from their tap, while only 1 of 10 white Americans didn't drink their tap water.
When children don't drink any water on a given day, research shows that they consume twice as many calories from sugary drinks as children who drink water. Higher sugary drink consumption increases risk of cavities, obesity and cardiometabolic diseases. Drinking tap water provides fluoride, which lowers the risk of cavities. Relying on water alternatives is also much more expensive than drinking tap water.
A4: Choosing to drink fluoridated tap water over sugar-sweetened beverages to quench thirst is vital to protecting… https://t.co/3tm8wuWjeZ— Oral Health Watch (@Oral Health Watch)1600795750.0
What Erodes Trust
News reports – particularly high-visibility events like advisories to boil water – lead people to distrust their tap water even after the problem is fixed. For example, a 2019 study showed that water quality violations across the U.S. between 2006 and 2015 led to increases in bottled water purchases in affected counties as a way to avoid tap water, and purchase rates remained elevated after the violation.
The Flint water crisis drew national attention to water insecurity, even though state and federal regulators were slow to respond to residents' complaints there. Soon afterward, lead contamination was found in the water supply of Newark, New Jersey; the city is currently replacing all lead service lines under a legal settlement. Elsewhere, media outlets and advocacy groups have reported finding tap water samples contaminated with industrial chemicals, lead, arsenic and other contaminants.
Many other factors can cause people to distrust their water supply, including smell, taste and appearance, as well as lower income levels. Location is also an issue: Older U.S. cities with aging infrastructure are more prone to water shutoffs and water quality problems.
It's important not to blame people for distrusting what comes out of their tap, because those fears are rooted in history. In my view, addressing water insecurity requires a two-part strategy: ensuring that everyone has access to clean water, and increasing trust so people who have safe water will use it.
Chart: The Conversation / CC BY-ND. Source: AWWA / Morning Consult. Get the data
Building Confidence
As part of his proposed infrastructure plan, President Joe Biden is asking Congress for $111 billion to improve water delivery systems, replace lead pipelines and tackle other contaminants. The plan also proposes improvements for small water systems and underserved communities.
These are critical steps to rebuild trust. Yet, in my view, the U.S. Environmental Protection Agency should also provide better public education about water quality testing and targeted interventions for vulnerable populations, such as children and underserved communities. Initiatives to simplify and improve water quality reports can help people understand what's in their water and what they can do if they think something is wrong with it.
Chart: The Conversation / CC BY-ND. Source: AWWA / Morning Consult. Get the data
Who delivers those messages is important. In areas like Flint, where former government officials have been indicted on charges including negligence and perjury in connection with the water crisis, the government's word alone won't rebuild trust. Instead, community members can fill this critical role.
Another priority is the 13%-15% of Americans who rely on private well water, which is not regulated under the Safe Drinking Water Act. These households are responsible for their own water quality testing. Public funding would help them test it regularly and address any problems.
Public distrust of tap water in the U.S. reflects decades of policies that have reduced access to reliable, safe drinking water in communities of color. Fixing water lines is important, but so is giving people confidence to turn on the tap.
Asher Rosinger is an assistant professor of biobehavioral health, anthropology, and demography and director of the Water, Health, and Nutrition Laboratory at Penn State University.
Disclosure statement: Asher Rosinger receives funding from the National Science Foundation on an unrelated project. This work was supported by the Ann Atherton Hertzler Early Career Professorship funds, and the Penn State Population Research Institute (NICHD P2CHD041025). The funders had no role in the research or interpretation of results.
Reposted with permission from The Conversation.
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