There's a new super green food in town that you will be hearing a lot about. It's called Wolffia globosa, better known as duckweed although it's also is called watermeal and water egg. While it's said to be the smallest aquatic plant on earth, Wolffia, is touted to be the next generation food source that's packed with protein and research is revealing it may also be a vegetarian source of vitamin B12. In a world quickly moving away from meat and toward healthier plant-based options, does Wolffia globosa deserve a seat at the dinner table? And what about duckweed supplements? Are they safe?
What is Wolffia Globosa?
Wolffia globosa, also known as duckweed is one of 38 species of the water lental family. Edible water lentils are green aquatic plants with flowers that float on the water or just underneath it. They are able to float due to air pockets that provide buoyancy. Wolffia globosa is sometimes called the world's smallest plant because it's only 0.4 to 0.8 mm in size. For centuries, the plant has been eaten as food in countries such as Thailand, Myanmar, and Laos. Wolffia globosa is also the only member of the duckweed genus that is found in China.
Where Can You Purchase Wolffia Globosa?
As the popularity and consumer demand grow, it's probable it will be available for sale at local health food and nutrition stores. You can also grow your own if you prefer. Duckweed may also be an ingredient in plant-based green powder drink mixes too. The best way to know if it's an ingredient is to check the Supplement Facts labels of green drinks. Check here to see if it's available on Amazon.
Wolffia Globosa Nutrition Information
This strain of duckweed is composed of:
- 43% to 46% protein
- 35% to 40% carbohydrates
- 9.5% to 12% fat
According to samples submitted to the European Food Safety Association (EFSA), 3.5 oz (100 grams) of duckweed contains the following vitamins and minerals, micronutrients, and phytonutrients:
|Beta carotene||20,000 mcg to 70,000 mcg|
|Niacin||6 mg to 7 mg|
|Thiamin||0.6 to 0.9 mg|
|Vitamin B12||2 mcg to 4 mcg|
|Pantothenic acid||0.3 mg to 0.8 mg|
|Vitamin B6||0.3 mg to 1.27 mg|
|Vitamin C||7 mg to 270 mg|
|Vitamin D2||0 to < 4 IU|
|Vitamin D3||0 to <4 IU|
|Alpha-tocopherol||16 mg to 30 mg|
|Beta tocopherol||0.3 mg to 0.4 mg|
|Gamma tocopherol||0 mg to 0.1 mg|
|Vitamin K 1||5 mg to 11 mg|
|Vitamin K 2||0.1 mg to .02 mg|
|Total polyphenols||382 mg to 700 mg|
|Total catechins||16.5 mg to 121 mg|
|Zeaxanthin||0.03 mg to 0.16 mg|
|Caffeic acid||44 mg to 110 mg|
|Ferulic acid||3.33 mg to 3.97 mg|
|p-coumaric acid||3.33 mg to 7.73 mg|
|Oxalic acid||230 mg to 637 mg|
The plant also contains omega-3 fatty acids of which alpha-linolenic acid has the highest concentration averaging 3.9%. The EFSA points out that the level of vitamin K1 (phylloquinone) is much higher than in other green leafy vegetables. Consuming, vitamin K-rich foods may be a hazard for people who take blood thinner medications like Coumadin (warfarin) so double-check with your physician and pharmacist.
Is Wolffia Globosa A Vegetarian Source Of Vitamin B 12?
Vitamin B12 (cyanocobalamin) is an essential nutrient that's well known for its role in producing red blood cells. Those who are deficient in vitamin B12 can suffer from anemia which causes people to fatigue easily. While energy depletion is well known, deficiency in B12 can also manifest itself in several other ways such as:
- reduced appetite
- nausea and diarrhea
- weight loss
- muscle weakness
- problems walking and maintaining balance
- being short-tempered and irritable
- having a faster-than-normal resting heart rate
- experiencing feelings of tingling or numbness in the feet and hands
Some also wonder if vitamin B12 deficiency may play a role in depression. Those at greater risk of having a B12 deficiency include people over 50, alcoholics, vegans, those who take the diabetes drug, metformin, and people who've undergone bariatric weight loss surgery.
While B12 is a water-soluble vitamin, it's an odd nutrient because humans can stockpile it for future use. The liver of healthy people stores about 1-2 years of this vitamin but if it's not replenished, deficiency eventually results. While animal foods have traditionally been seen as good sources, this option is unacceptable for vegans.
Fortunately, B12 is found in shiitake mushrooms, tempeh, spirulina, and fermented black tea but what other foods contain this nutrient? When researchers analyzed a strain of Wolffia globosa called Mankai, it was discovered it also contains B12. In fact, one cup of Mankai is about 21% vitamin B12.
More to the point, the vitamin appears to be able to be absorbed by the body too, so it is active B12. Mankai Wolffia globosa has also been shown to raise B12 levels in the body better than pea protein or cheese. Claiming superiority over pea protein is not a big accomplishment since peas do not contain vitamin B12. Cheese does contain it though.
The Problem With Woffia & B12 Levels
In this study, Wolffia globosa failed to boost B12 levels significantly higher than they were at the start of the study. In other words, B12 levels rose, but they did not increase significantly more. This indicates Mankai duckweed supplements may be inferior to vitamin B12 supplements or foods and may not be appropriate for vegans. Mankai is a trademarked name of Wolffia globosa, registered with the Hinoman LTD company that makes Wolffia supplements and funds much of the research on this edible plant. They also own the patent too (US Plant Patent number PP29977).
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Can Wolffia Globosa Boost Iron Levels and Help Anemia?
Like other plants such as spinach and kale, Mankai duckweed is high in phytates which can inhibit iron absorption. Thus, in theory, a diet high in duckweed may put people at a higher risk of anemia. To test if this really happens, researchers recruited 294 overweight, not-anemic men and women and split them into the following 3 groups:
- Exercise (mostly aerobic exercise)
- Low-calorie Mediterranian diet + exercise
- Mediterranian diet + 16 oz daily duckweed protein shake + exercise
The Results: those who supplemented with Wolffia Globosa plant shakes:
- Lost more body weight
- Had higher iron levels than the exercise group but not significantly higher than the Mediterranian diet group + exercise
- Had significantly higher hemoglobin levels (compared to at the start of the study)
- Ferritin levels declined in all groups compared at the start of the study
Based on this study, it was concluded that drinking duckweed plant shakes did not reduce iron levels even though the plant contains high levels of iron-blocking phytates.
This study also revealed that in rats, Mankai reversed anemia. Can it also reverse anemia in people? None of the people in this study were anemic so more research is needed.
What About Weight Loss?
As to the question of Wolffia Globosa helping with weight loss, here is the weight reduction after 6 months:
- Duckweed shakes + Mediterranian diet + exercise: lost 13.6 pounds
- Mediterranian diet + exercise: lost 12 pounds
- Exercise-only group: lost 3.3 pounds
As you can see, the weight loss was only about 1.6 pounds more when people added Duckweed plant shakes to the Mediterranean diet.
Can Duckweed Improve Gut Microbiome Health?
In a separate portion of the above study, researchers wanted to see if duckweed had any effects on gut health. They did this by giving some people fecal microbiome transplants and monitoring changes in gut bacteria during weight loss. The research team documented that duckweed shakes appeared to favorably stabilize the gut microbiome during weight loss. However, this did not prevent people from regaining body weight after the study had ended and they returned to their old lifestyle habits. Based on this, duckweed supplements -by themselves- might not be effective for maintaining weight loss.
What About Lowering Cholesterol Levels and Being Heart Healthy?
Some research suggests the supplement may significantly reduce total cholesterol levels by about 25%. While impressive, this doesn't address the more important question which is whether eating more Wolffia globosa can reduce the risk of heart disease or heart attacks. Studies also need to shed light on whether this edible aquatic plant lowers bad LDL cholesterol levels.
How Much Protein Does Wolffia Globosa Have?
People exploring the benefits of a plant-based diet and meat alternatives may have heard claims about Duckweed protein being the next generation food source. Indeed, in southeast Asia, duckweed is often called a “vegetable meatball.” Another reference to its protein comes from Thailand where it's referred to as “eggs of the water.”
Wolffia globosa contains all 9 essential amino acids, including the branch chain amino acids (BCAAs), leucine, isoleucine, and valine. That's important because humans cannot manufacture essential amino acids. Duckweed also contains 6 conditionally amino acids too.
In addition, 89% of the protein consumed is digested. Further bolstering the rich in protein claims is research that finds 45% of the dry weight of duckweed is protein. So does Wolffia globosa live up to its meat substitute reputation? When researchers gave 36 men, a meal containing three different proteins:
- Pea protein
- Cheese protein
- Mankai Wolffia globosa protein
After 3 hours, all of the protein-based meals raised essential amino acid levels although when it came to the branch chain amino acids (leucine, isoleucine, and valine) cheese raised BCAA levels more than Mankai Wolffia duckweed protein. Another possible problem is that since pea protein does not naturally contain B12, how did the pea protein meal raise levels of this nutrient?
Does Wolffia Globosa Duckweed Help Diabetes and Elevated Blood Sugar?
Duckweed may offer benefits for people with hyperglycemia and type II diabetes. When researchers gave 20 overweight men and women with abdominal obesity -some of whom had prediabetes and type II diabetes – low-fat meal replacement protein shakes made from either Mankai Wolffia globosa or yogurt, it was discovered after 2 weeks, those who drank the duckweed shake at dinner time had lower blood sugar levels afterward.
Lower postprandial blood sugar levels may benefit people with metabolic syndrome, one of the hallmarks of type II diabetes. It's not yet known if Mankai lowers hemoglobin A1c levels. So how did duckweed reduce blood sugar levels? It may be because it has more fiber than yogurt does (9 grams vs. 5 grams). The polyphenols in duckweed may have reduced sugar levels too.
Duckweed Plant Shake vs. Yogurt Shake Nutrition Breakdown
|Duckweed plant shake 75 g (2.7 oz)||Yogurt shake 100g (3.5 oz)|
|carbs||35 g||35 g|
|protein||12 g||11 g|
|fat||20 g||19 g|
|fiber||9 g||5 g|
The meal replacement shakes also contained 1 banana and 28 grams (1 oz) of walnuts
People drinking the duckweed shake also rated it as more satiating than the yogurt shake too. This may mean it curbs appetite.
Duckweed, BPH, and Prostate Health
Preliminary evidence from animals, suggests Wolffia globosa significantly reduces the size of the prostate gland. In theory, this may be good news for men dealing with benign prostate hyperplasia (BPH), a condition of enlarged prostates that often affects men over 50. While encouraging, more research is needed to see if duckweed reduces BPH symptoms (like nighttime urination) or if it should be an active ingredient in men's health supplements.
Wolffia Globosa Side Effects, Adverse Reactions, and Contraindications
Human studies have not reported negative side effects from this editable plant. Duckweed has also been eaten as food for centuries. So far research does not show toxic effects on human cells either. Does this mean duckweed is safe? Probably yes when consumed as a source of food. While the same may also be true for dietary supplements of Wolffia globosa, this should be investigated further.
Factors that could influence safety may include the water and environment the duckweed is grown in. Like all green foods, Wolffia can collect toxins from the environment in which it is grown. Thus, companies need to ensure environmental toxins are kept below safe thresholds.
Duckweed Quick Takeaways On Side Effects and Considerations
- Speak to your doctor and pharmacist if you take any medications
- Duckweed supplements are not intended for children
- Avoid duckweed supplements if you are pregnant or breastfeeding
- Stop consuming this green food at least 2 weeks before having surgery
- Vitamin K is important for the blood clotting process. Since duckweed contains high levels of vitamin K1 compared to other green leafy vegetables, supplements could lead to vitamin K intakes of at least 2.4 mg per day. At this dosage, the European Food Safety Association (EFSA) speculated duckweed supplements may interfere with blood thinner medications such as warfarin, also known as coumadin.
- A kilogram (2.2 pounds) of Duckweed contains 116.5 mg of manganese which is much more than found in similar weights of other foods such as nuts and seeds (11.9 mg), chocolate (8.9 mg), and bread (8 mg). While manganese is an essential trace nutrient, animal research suggests elevated manganese intake could be harmful to the brain, producing Parkinson's' disease-like symptoms. This has not been documented in people who eat Wolffia globosa as a food. There is no RDA for manganese but intakes for adults of 1.8 to 2.3 mg per day have not shown negative side effects.
What Are The Pros & Cons Of Wolffia Globosa Duckweed?
|Research exists||Unknown if B12 levels rise enough to be suitable for vegans|
|Contains protein||Supplements may be expensive|
|Contains essential fatty acids||Probably doesn’t help weight loss|
|Has vitamin B12|
|Contains all 9 essential amino acids|
What's The Verdict On Eating Wolfia Globosia Or Using Supplements?
So far, the research on duckweed supplements shows it has vitamin B12 and protein, and essential omega-3 fatty acids which may make it suitable as an alternative plant-based food source. The research on duckweed supplements is also interesting although I'd like to see a few other investigations to better flush out whether its B12 content can prevent or reverse deficiency in vegans. Like other “superfoods,” you've heard about, there's bound to be lots of hype surrounding Makaki duckweed supplements so listen to your gut instincts about claims sounding too good to be true. If you have any questions, post them below.