Shirataki noodles are a unique food that's very filling yet low in calories.
These noodles also contain a type of fiber that has impressive health benefits.
In fact, this fiber has been shown to cause weight loss in numerous studies.
This article explains everything you need to know about shirataki noodles and their benefits.
It also provides recipes and detailed instructions about how to prepare them.
What are Shirataki Noodles?
Shirataki noodles are long, white noodles. They are often called miracle noodles or konjac noodles.
Konjac grows in Japan, China and Southeast Asia. It contains very few digestible carbs, but most of its carbs come from glucomannan fiber.
“Shirataki" is Japanese for “white waterfall," which describes the noodles' translucent appearance.
The noodles are made by combining glucomannan flour with water and a small amount of lime water, which helps the noodles hold their shape.
The mixture is boiled and then shaped into noodles or rice.
Shirataki noodles contain a lot of water. In fact, they are about 97 percent water and 3 percent glucomannan fiber. They're also very low in calories and contain no digestible carbs.
There is also a variation of shirataki noodles known as tofu shirataki noodles.
Bottom Line: Shirataki noodles are a low-calorie food made from glucomannan, a type of fiber found in the Asian konjac plant.
Shirataki Noodles Are High in Viscous Fiber
Glucomannan is a highly viscous fiber. Viscous fiber is a type of soluble fiber and one of its main characteristics is the ability to absorb water and form a gel.
In fact, glucomannan can absorb up to 50 times its weight in water, as reflected in shirataki noodles' extremely high water content (1).
These noodles move through the digestive system very slowly, which helps you feel full and delays nutrient absorption into the bloodstream (2).
In addition, viscous fiber functions as a prebiotic. It nourishes the bacteria living in your colon, also known as the gut flora or microbiome.
A recent human study found that fermenting glucomannan fiber to short-chain fatty acids produces one calorie per gram (6).
Since a typical serving of shirataki noodles contains about 1–3 grams of glucomannan, it's essentially a calorie-free, carb-free food.
Bottom Line: Glucomannan is a viscous fiber that can hold onto water and slow down digestion. In the colon, it's fermented into short-chain fatty acids that may provide several health benefits.
Shirataki Noodles Can Help You Lose Weight
Shirataki noodles can be a powerful weight loss tool.
In addition, fermenting fiber into short-chain fatty acids can stimulate the release of a gut hormone known as PYY, which increases feelings of fullness (9).
What's more, taking glucomannan before a high-carb load appears to reduce levels of the “hunger hormone" ghrelin. It was also shown to reduce fasting ghrelin levels when taken daily for 4 weeks (10).
Researchers who analyzed 7 weight loss studies found that people who took glucomannan for 4–8 weeks lost 3–5.5 lbs (1.4–2.5 kg) (1).
In one study, people who took glucomannan alone or with other types of fiber lost significantly more weight on a low-calorie diet, compared to the placebo group (11).
In another study, obese people who took glucomannan every day for 8 weeks lost 5.5 lbs (2.5 kg) without eating less or changing their exercise habits (12).
However, another 8-week study found no difference in weight loss between overweight and obese people who took glucomannan and those who did not (13).
Since these studies used 2–4 grams of glucomannan in tablet or supplement form taken with water, shirataki noodles would likely have similar effects.
Nevertheless, there are no studies available on shirataki noodles specifically.
Additionally, timing may play a role. Glucomannan is typically taken up to an hour before a meal, while the noodles are eaten as part of the meal.
Bottom Line: Glucomannan promotes feelings of fullness that may cause a spontaneous reduction in calorie intake and lead to weight loss.
Shirataki Noodles Can Reduce Blood Sugar and Insulin Levels
Because viscous fiber delays stomach emptying, blood sugar and insulin levels rise more gradually as nutrients are absorbed into the bloodstream (19).
In one study, people with type 2 diabetes who took glucomannan for 3 weeks had a significant reduction in fructosamine, which is a test that reflects blood sugar levels over a period of 2–3 weeks (17).
In another study, type 2 diabetics who took a single dose of glucomannan before a glucose load had significantly lower blood sugar levels 2 hours later, compared to their blood sugar response to a placebo (18).
Bottom Line: Shirataki noodles can delay stomach emptying, which may help prevent blood sugar spikes after meals.
Shirataki Noodles May Lower Cholesterol
Researchers have reported that glucomannan increases the amount of cholesterol excreted in the stool, so less is reabsorbed into the bloodstream (15).
A review of 14 studies found that glucomannan lowered LDL cholesterol by an average of 16 mg/dL and triglycerides by an average of 11 mg/dl (22).
Bottom Line: Studies show that glucomannan may help lower LDL cholesterol and triglyceride levels.
Shirataki Noodles May Relieve Constipation
Many people have chronic constipation or infrequent bowel movements that are difficult to pass.
In one study, severe constipation was successfully treated in 45 percent of the children taking glucomannan, compared to only 13 percent of the control group (25).
Bottom Line: Glucomannan may effectively treat constipation in children and adults, due to its laxative effects and benefits for gut health.
Potential Side Effects of Shirataki Noodles
However, it should be noted that glucomannan has been found to be safe at all dosages tested in studies.
Nevertheless, as is the case with all fiber, it's best to introduce glucomannan into your diet gradually.
In addition, glucomannan may reduce the absorption of certain medications taken by mouth, including some diabetes medications. To prevent this, make sure to take medication at least one hour before or four hours after eating shirataki noodles.
Bottom Line: Shirataki noodles are safe to consume, but may cause digestive issues for some. They may also reduce the absorption of certain medications.
How to Cook with Shirataki Noodles
Shirataki noodles can seem a bit daunting to prepare at first.
They're packaged in fishy-smelling liquid, which is actually plain water that has absorbed the odor of the konjac root.
Therefore, it's important to rinse them very well for a few minutes under fresh, running water. This should remove most of the odor.
You should also heat the noodles in a skillet for several minutes with no added fat.
This step removes any excess water and allows the noodles to take on a more noodle-like texture. If too much water remains, they will be mushy.
Here is an easy shirataki noodle recipe containing only a few ingredients:
Shirataki Macaroni and Cheese
Note: For this recipe, it's best to use shorter types of shirataki noodles like ziti or rice.
- 1 package (200 grams/7 oz) of shirataki noodles or shirataki rice.
- Olive oil or butter for greasing the ramekin.
- 3 ounces (85 grams) of grated cheddar cheese.
- 1 Tablespoon butter.
- A half teaspoon sea salt.
1. Preheat oven to 350 F (175 C).
2. Rinse the noodles under running water for at least 2 minutes.
3. Transfer the noodles to a skillet and cook over medium-high heat for 5–10 minutes, stirring occasionally.
4. While the noodles are cooking, grease a 2-cup ramekin with olive oil or butter.
5. Transfer the cooked noodles to the ramekin, add remaining ingredients and stir well. Bake for 20 minutes, remove from oven and serve.
Shirataki noodles can be used in place of pasta or rice in any dish.
However, they tend to work best in Asian recipes. The noodles have no flavor but will absorb the flavors of sauces and seasonings very well.
Here are a few more healthy shirataki noodle recipes:
Bottom Line: Shirataki noodles are easy to prepare and can be used in a variety of dishes. They're especially tasty in Asian recipes.
Take Home Message
Shirataki noodles are a great substitute for traditional noodles.
In addition to being extremely low in calories, they help you feel full and may be beneficial for weight loss.
Not only that, but they also have benefits for blood sugar levels, cholesterol and digestive health.
This article was reposted from our media associate Authority Nutrition.
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By Lynne Peeples
Editor's note: This story is part of a nine-month investigation of drinking water contamination across the U.S. The series is supported by funding from the Park Foundation and Water Foundation. Read the launch story, "Thirsting for Solutions," here.
In late September 2020, officials in Wrangell, Alaska, warned residents who were elderly, pregnant or had health problems to avoid drinking the city's tap water — unless they could filter it on their own.
Unintended Consequences<p>Chemists first discovered disinfection by-products in treated drinking water in the 1970s. The trihalomethanes they found, they determined, had resulted from the reaction of chlorine with natural organic matter. Since then, scientists have identified more than 700 additional disinfection by-products. "And those only represent a portion. We still don't know half of them," says Richardson, whose lab has identified hundreds of disinfection by-products. </p>
What’s Regulated and What’s Not?<p>The U.S. Environmental Protection Agency (EPA) currently regulates 11 disinfection by-products — including a handful of trihalomethanes (THM) and haloacetic acids (HAA). While these represent only a small fraction of all disinfection by-products, EPA aims to use their presence to indicate the presence of other disinfection by-products. "The general idea is if you control THMs and HAAs, you implicitly or by default control everything else as well," says Korshin.</p><p>EPA also requires drinking water facilities to use techniques to reduce the concentration of organic materials before applying disinfectants, and regulates the quantity of disinfectants that systems use. These rules ultimately can help control levels of disinfection by-products in drinking water.</p>
Click the image for an interactive version of this chart on the Environmental Working Group website.<p>Still, some scientists and advocates argue that current regulations do not go far enough to protect the public. Many question whether the government is regulating the right disinfection by-products, and if water systems are doing enough to reduce disinfection by-products. EPA is now seeking public input as it considers potential revisions to regulations, including the possibility of regulating additional by-products. The agency held a <a href="https://www.epa.gov/dwsixyearreview/potential-revisions-microbial-and-disinfection-byproducts-rules" target="_blank">two-day public meeting</a> in October 2020 and plans to hold additional public meetings throughout 2021.</p><p>When EPA set regulations on disinfection by-products between the 1970s and early 2000s, the agency, as well as the scientific community, was primarily focused on by-products of reactions between organics and chlorine — historically the most common drinking water disinfectant. But the science has become increasingly clear that these chlorinated chemicals represent a fraction of the by-product problem.</p><p>For example, bromide or iodide can get caught up in the reaction, too. This is common where seawater penetrates a drinking water source. By itself, bromide is innocuous, says Korshin. "But it is extremely [reactive] with organics," he says. "As bromide levels increase with normal treatment, then concentrations of brominated disinfection by-products will increase quite rapidly."</p><p><a href="https://pubmed.ncbi.nlm.nih.gov/15487777/" target="_blank">Emerging</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b05440" target="_blank" rel="noopener noreferrer">data</a> indicate that brominated and iodinated by-products are potentially more harmful than the regulated by-products.</p><p>Almost half of the U.S. population lives within 50 miles of either the Atlantic or Pacific coasts, where saltwater intrusion can be a problem for drinking water supplies. "In the U.S., the rule of thumb is the closer to the sea, the more bromide you have," says Korshin, noting there are also places where bromide naturally leaches out from the soil. Still, some coastal areas tend to be spared. For example, the city of Seattle's water comes from the mountains, never making contact with seawater and tending to pick up minimal organic matter.</p><p>Hazardous disinfection by-products can also be an issue with desalination for drinking water. "As <a href="https://ensia.com/features/can-saltwater-quench-our-growing-thirst/" target="_blank" rel="noopener noreferrer">desalination</a> practices become more economical, then the issue of controlling bromide becomes quite important," adds Korshin.</p>
Other Hot Spots<p>Coastal areas represent just one type of hot spot for disinfection by-products. Agricultural regions tend to send organic matter — such as fertilizer and animal waste — into waterways. Areas with warmer climates generally have higher levels of natural organic matter. And nearly any urban area can be prone to stormwater runoff or combined sewer overflows, which can contain rainwater as well as untreated human waste, industrial wastewater, hazardous materials and organic debris. These events are especially common along the East Coast, notes Sydney Evans, a science analyst with the nonprofit Environmental Working Group (EWG, a collaborator on <a href="https://ensia.com/ensia-collections/troubled-waters/" target="_blank">this reporting project</a>).</p><p>The only drinking water sources that might be altogether free of disinfection by-products, suggests Richardson, are private wells that are not treated with disinfectants. She used to drink water from her own well. "It was always cold, coming from great depth through clay and granite," she says. "It was fabulous."</p><p>Today, Richardson gets her water from a city system that uses chloramine.</p>
Toxic Treadmill<p>Most community water systems in the U.S. use chlorine for disinfection in their treatment plant. Because disinfectants are needed to prevent bacteria growth as the water travels to the homes at the ends of the distribution lines, sometimes a second round of disinfection is also added in the pipes.</p><p>Here, systems usually opt for either chlorine or chloramine. "Chloramination is more long-lasting and does not form as many disinfection by-products through the system," says Steve Via, director of federal relations at the American Water Works Association. "Some studies show that chloramination may be more protective against organisms that inhabit biofilms such as Legionella."</p>
Alternative Approaches<p>When he moved to the U.S. from Germany, Prasse says he immediately noticed the bad taste of the water. "You can taste the chlorine here. That's not the case in Germany," he says.</p><p>In his home country, water systems use chlorine — if at all — at lower concentrations and at the very end of treatment. In the Netherlands, <a href="https://dwes.copernicus.org/articles/2/1/2009/dwes-2-1-2009.pdf" target="_blank">chlorine isn't used at all</a> as the risks are considered to outweigh the benefits, says Prasse. He notes the challenge in making a convincing connection between exposure to low concentrations of disinfection by-products and health effects, such as cancer, that can occur decades later. In contrast, exposure to a pathogen can make someone sick very quickly.</p><p>But many countries in Europe have not waited for proof and have taken a precautionary approach to reduce potential risk. The emphasis there is on alternative approaches for primary disinfection such as ozone or <a href="https://www.pbs.org/wgbh/nova/article/eco-friendly-way-disinfect-water-using-light/" target="_blank" rel="noopener noreferrer">ultraviolet light</a>. Reverse osmosis is among the "high-end" options, used to remove organic and inorganics from the water. While expensive, says Prasse, the method of forcing water through a semipermeable membrane is growing in popularity for systems that want to reuse wastewater for drinking water purposes.</p><p>Remucal notes that some treatment technologies may be good at removing a particular type of contaminant while being ineffective at removing another. "We need to think about the whole soup when we think about treatment," she says. What's more, Remucal explains, the mixture of contaminants may impact the body differently than any one chemical on its own. </p><p>Richardson's preferred treatment method is filtering the water with granulated activated carbon, followed by a low dose of chlorine.</p><p>Granulated activated carbon is essentially the same stuff that's in a household filter. (EWG recommends that consumers use a <a href="https://www.ewg.org/tapwater/reviewed-disinfection-byproducts.php#:~:text=EWG%20recommends%20using%20a%20home,as%20trihalomethanes%20and%20haloacetic%20acids." target="_blank" rel="noopener noreferrer">countertop carbon filter</a> to reduce levels of disinfection by-products.) While such a filter "would remove disinfection by-products after they're formed, in the plant they remove precursors before they form by-products," explains Richardson. She coauthored a <a href="https://pubs.acs.org/doi/10.1021/acs.est.9b00023" target="_blank" rel="noopener noreferrer">2019 paper</a> that concluded the treatment method is effective in reducing a wide range of regulated and unregulated disinfection by-products.</p><br>
Greater Cincinnati Water Works installed a granulated activated carbon system in 1992, and is still one of relatively few full-scale plants that uses the technology. Courtesy of Greater Cincinnati Water Works.<p>Despite the technology and its benefits being known for decades, relatively few full-scale plants use granulated active carbon. They often cite its high cost, Richardson says. "They say that, but the city of Cincinnati [Ohio] has not gone bankrupt using it," she says. "So, I'm not buying that argument anymore."</p><p>Greater Cincinnati Water Works installed a granulated activated carbon system in 1992. On a video call in December, Jeff Swertfeger, the superintendent of Greater Cincinnati Water Works, poured grains of what looks like black sand out of a glass tube and into his hand. It was actually crushed coal that has been baked in a furnace. Under a microscope, each grain looks like a sponge, said Swertfeger. When water passes over the carbon grains, he explained, open tunnels and pores provide extensive surface area to absorb contaminants.</p><p>While the granulated activated carbon initially was installed to address chemical spills and other industrial contamination concerns in the Ohio River, Cincinnati's main drinking water source, Swertfeger notes that the substance has turned out to "remove a lot of other stuff, too," including <a href="https://ensia.com/features/drinking-water-contamination-pfas-health/" target="_blank" rel="noopener noreferrer">PFAS</a> and disinfection by-product precursors.</p><p>"We use about one-third the amount of chlorine as we did before. It smells and tastes a lot better," he says. "The use of granulated activated carbon has resulted in lower disinfection by-products across the board."</p><p>Richardson is optimistic about being able to reduce risks from disinfection by-products in the future. "If we're smart, we can still kill those pathogens and lower our chemical disinfection by-product exposure at the same time," she says.</p><p><em>Reposted with permission from </em><em><a href="https://ensia.com/features/drinking-water-disinfection-byproducts-pathogens/" target="_blank">Ensia</a>. </em><a href="https://www.ecowatch.com/r/entryeditor/2649953730#/" target="_self"></a></p>
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