Science

New study shows promise that Sargassum sp. improves blood biochemistry profiles

Marine algae have anti-oxidant, anti-inflammatory, antidiabetic, and anti-cancer potential. Sargassum sp. is a type of brown algae that possess pharmacological properties, such as anti-oxidant, anti-inflammatory, anti-hypertensive, anti-bacterial, and anti-viral activities. These pharmacological properties are a result of the biological activity of metabolites such as alkaloids, steroids, terpenoids, saponins, polyphenols, phlorotannin, and fucoidan.

In a recent study, researchers used a rat model to assess treating in vivo stress (swimming model) with Sargassum by measuring levels of glucose, triacylglycerol, total cholesterol, and cortisol, and liver histopathology.

The results were very promising. Rats fed Sargassum (450 mg/kg) has similar results as when treated with diazepam (0.18 mg/kg). The Sargassum treatment improved blood glucose, triacylglycerol, total cholesterol, and cortisol levels and liver histology by decreasing the severity of inflammation.

This news couldn’t come at a better time. Sargassum is currently overrunning beaches due to ocean warming and eutrophication. Even better, this study simply used dry powdered Sargassum. There were no costly extraction methods, meaning anyone simply eating Sargassum could potentially benefit.

This work was published in the journal of Preventive Nutrition and Food Science.

Why do cooked seaweeds turn green?

Seaweeds, like any vegetable, can be prepared in a number of ways. They can be eaten raw, fried, baked, boiled, and dried. Each method changes the texture, taste, and in some cases, color.

If you haven’t seen the magic like color change of cooked seaweeds, watch the video below.

Here you see someone blanching kelp, where it turns from brown to bright green in seconds. This happens whenever a brown or red seaweed is heated, but why? As you probably remember from high school biology, plants get their green color from the light harvesting pigment chlorophyll. Seaweeds are no different, red, green, and brown seaweeds contain chlorophyll. However, brown and red seaweeds have additional pigments that give them a different colors; red seaweeds have phycoerythrin while brown seaweeds have fucoxanthin (image below).

It turns out that chlorophyll has a higher melting point (~150 C) than phycoerythrin and fucoxanthin. When Seaweeds are added to boiling water (100 C) the other pigments melt and dissolve leaving behind the bright green chlorophyll. This trick is used for the iconic seaweed salad (wakame). Just as in the video above, wakame starts out brown and is blanched to attain the attractive bright green color.

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Animals fed an algae rich diet produced more nutritious milk.

You truly are what you eat, or what your food eats. A recent study in the Journal of Animal Feed Science wanted to see if feeding goats algae would affect their milk production or quality. In the study, the researchers used the marine microalga Schizochytrium limacinum because of it’s known high fatty acid content of DHA.

Forty dairy goats were tested with varying diets for 31 days, and some groups were supplemented with the algae. The researchers concluded the algae feeding had no negative effect on milk yield and milk composition. However, the microalgae inclusion considerably increased DHA concentration in milk. Additionally, the n-6/n-3 ratio was also more favorable in the microalgae supplemented groups. The 6:3 ratio was reduced from 2.3 to 1.25 indicating higher levels of omega-3’s.

While this study used microalgae, there is considerable research currently on feeding cattle seaweeds for methane reduction. An interesting additional benefit may be more nutritious milk as seaweeds are also rich in omega-3’s.

Seaweeds are one of the best things to eat to help preserve biodiversity and the planet

Last month, the United Nations released a report on biodiversity and ecosystems that found 1 million plant and animal species are currently facing extinction.

The World Wildlife Fund argues dietary monotony leads to a decline in biodiversity since many animals can’t thrive on land that has been transformed to farmlands. Did you know that 75% of the global food supply comes from just 12 plant and five animal species?

In response to this issue, the WWF published “Future 50 Foods,” a list of “foods we should eat more of because they are nutritious, have a lower impact on our planet than animal-based foods, can be affordable, accessible, and taste good.”

On this list there are two seaweed recommendations, wakame, and nori. While the authors clearly selected these on market availability, the same arguments can be made for a variety of seaweeds available by seaweed farms and local foragers.

Variety is the spice of life, but now it seems like it also might be what saves species diversity.

seaweeds to combat hypertension

On Tuesday the Central Marine Fisheries Research Institute (CMFRI) came out with a nutraceutical product, developed from seaweeds, to combat hypertension (high blood pressure).

CadalminTM AHe was developed from seaweeds, commonly available in the Indian coastal waters.

Kajal Chakraborty, the Senior Scientist at the CMFRI who developed the product said, "The extract contains 100 per cent natural marine bioactive ingredients from selected seaweeds by a patented technology, and would be made available in 400 mg capsules. This nutraceutical does not have any side effects as established by detailed preclinical trials. The institute is in the process of developing more health products from the underutilized seaweeds. Efforts are on for standardizing and promoting seaweed farming all along the Indian coasts as a livelihood option for the coastal communities. This is expected to compensate for the dip in income for the fishermen during lean seasons."

Seaweeds have been shown in other studies to reduce hypertension, just as other health foods such as fruits and vegetables. However, the researchers at CMFRI have focused on an underutilized resource that could also have strong positive economic impacts.

Fucoidan used in diet therapy for the prevention and treatment of diabetes mellitus

A new article just published in the Journal of Pharmacy and Pharmacology, reviewed the primary research surrounding fucoidan and its health benefits. Fucoidan is a complex polysaccharide found in many species of brown seaweed. It is said to be an antioxidant, antibacterial, antiviral, anticoagulant, anti-inflammatory, and antitumor. The researchers admit, “such a wide range of biological effects of fucoidan causes mistrust, therefore legitimate to ask a myth or reality.” The study focused on the antidiabetic properties of fucoidan, by reviewing preclinical studies on invitro models (on separate cell systems) and in vivo (on various laboratory animals) and the first phase of clinical trials—tolerability and safety as well as pilot studies were conducted on the second phase of clinical trials.

The review concluded that sulfated polysaccharide fucoidan promotes maintaining homeostasis of glucose due to the decrease rate of its absorption in the gut and increase in utilization of muscle fibers, which leads to the prevention of the development of glycaemia and lipedema. The positive effect fucoidan at diabetes mellitus linked to its antioxidant properties and ability to reduce manifestations of apoptosis, in particular, beta cells of pancreas, which save the ability of cells to secrete insulin. And therefore, fucoidan should be clacified as a functional food for diet therapy for the prevention and treatment of diabetes mellitus.

Fucoidan is currently available on the market as a supplement, or you could consume it as people in Japan and Korea have for centuries, by eating brown seaweeds.

The race to the methane-free cash cow

Methane is a greenhouse gas many times more potent than carbon dioxide, and livestock accounts for about 14.5% of climate-warming emissions worldwide, according to the United Nations' Intergovernmental Panel on Climate Change. For the past decade, researchers have been investigating the causes and remedies of methane produced by cattle. Between 2016 and 2018 the topic heated to a boil with the discovery that adding seaweed to cattle feed reduced methane burps, especially the red macroalga, Asparagopsis taxiformis.

The race is on!

Scientists all over the world are now intensively working on how to maximize the economic and environmental effectiveness. Researchers are pointing to the bromoform produced by Asparaopsis as the key compound that blocks the production of methane in cows, sheep, goats and other ruminant animals. By changing growing conditions, such as nitrogen and phosphorous, the bromoform concentration can be more than doubled.

Experts are currently debating in which stage to grow the seaweed. The practical considerations include not only the cost of cultivation but its carbon footprint. If growing the seaweed and shipping it to farms generates considerable amounts of greenhouse gas, the process could cancel out the benefits of reducing methane.

Growing Asparagopsis would likely require doing so in tanks of sterilized seawater to prevent contamination of the clingy plant material. That means using some form of energy to pump in air and nitrogen. The problem is it's going to be expensive. The ultimate goal is the most scalable and lowest cost method of production, and to achieve this some point to offshore farming rather than in tanks on land.

There is still some uncertainty with respect to the cattle as well. Will seaweeds reduce methane indefinitely, are there any negative effects to the animals, and will the cows voluntarily eat seaweed infused feed? To address these questions, Ermias Kebreab, an animal science professor at UC Davis, is currently conducting a 6 month feeding trial with cattle.

Many of the outstanding questions will be answered soon enough. Whether motivated by profits or global warming, the race is on to patent recipes for growing, scaling, and processing seaweed for animal feed.

The man who discovered umami

Did you know we owe seaweed for helping discover umami?

Kikunae Ikeda a Japanese chemist and professor at Tokyo Imperial University had been studying a broth made from seaweed and dried fish flakes called dashi. Through numerous chemical assays, Ikeda had been trying to isolate the molecules behind its distinctive taste. In a 1909 paper, Ikeda claimed the flavor in question came from the amino acid glutamate, a building block of proteins. He suggested that the savory sensation triggered by glutamate should be one of the basic tastes that give something flavor, on a par with sweet, sour, bitter, and salt. He called it “umami”, riffing on a Japanese word meaning “delicious”.

Ikeda’s paper was not well received, and it took over a hundred years for the term “umami” to be internationally recognized. Over the decades, scientists began to put together how umami works. Each new insight brought the claim put forth by Ikeda into better focus. The discovery that made umami stick was about 20 years ago, showing that there are specific receptors in taste buds that pick up on amino acids. Multiple research groups have now reported on these receptors, which are tuned to specifically stick onto glutamate.

Ikeda, found a seasoning manufacturer and started to produce his own line of umami seasoning. The product, a monosodium glutamate (MSG) powder called Aji-No-Moto, is still made today. (Although rumors have swirled periodically that eating too much MSG can give people headaches and other health problems, the US Food and Drug Administration has found no evidence for such claims. It just makes food taste more savory.)     

While other food items have umami flavors, it was seaweed that gave the term life.

A new book, “Enzymatic Technologies for Marine Polysaccharides” contains an interesting chapter on seaweeds called, “The manufacture, characterization, and uses of fucoidans from macroalgae.

Fucoidans are sulfated, complex, fucose-rich, polymers found in brown seaweeds, most notably the order Fucales known as the fucoids. The chapter details extraction methods and uses in food supplements, pharmaceuticals, bio-materials, cosmetics, and animal/ agricultural applications.

The authors claim that most fucoidan available on the market are for dietary supplementation, however, they admit that the molecule species is hard to identify and robust identification assays should be employed in any bioactive study. There is a new interest in animal health relating to fucoidan, and could be an emerging market.

Focoidans are considered safe and have a variety of uses, again showing how a completely sustainable resource (seaweeds) have a variety of revenue streams.

Seaweed inspired organic sunscreen

As we leave winter behind, it will soon be time to dust off the sunglasses and purchase a bottle of your favorite sunscreen.

Sunscreens have received a lot of bad press lately, either because of their ability to damage skin or because they wash off into the ocean and are toxic to marine life. An Icelandic company Taramar has been working to address these issues. Taramar focuses on skin health by the use of natural molecules found in plants. Recently they turned their attention to seaweed.

Their result was the TARASÓL UV filter which lacks preservatives and is safe for the skin and body.

Professor Gudrun Marteinsdottir, founder and CEO of Taramar, says, “TARASÓL is the result of years of basic research in marine biology and nutritional science leading to new knowledge on the functional properties of seaweed.″

Taramar has not disclosed the molecule from seaweed. However, we know that plants have developed ways of avoiding UV damage and this could be a good way to harness what nature already knows to produce a safe organic alternative to traditional sunscreens.

Operation Crayweed: restoring Sydney's underwater forests.

Sydney Australia used to have a rich coastline teeming with life, and crayweed (Phyllospora comosa) stretched far and wide. Crayweed is a brown macroalga that forms dense bushy habitat for a variety of marine life. Sometime back in the 80s, crayweed largely disappeared, and much of the inhabitants with it. While the cause of the crayweed reduction was unclear, many point to prolonged poor water quality.

The water quality in Sydney has improved, but the crayweed didn’t bounce back as expected. Thus enters Operation Crayweed, an effort to restore the natural population of crayweed around Sydney. The group settles crayweed onto mats, then divers deploy and secure the mats so the crayweed can naturally spread.

Below is a wonderful video outlining the effort. What a good way to rebuild an ecosystem, from the bottom up! Read more about Operation Crayweed at http://www.operationcrayweed.com/

Seaweed in your garden: a good fertilizer and potential pest control

Many people around the world for centuries have known that seaweeds are an excellent fertilizer. Recently people have been reporting another benefit of using seaweeds in their garden, pest control.

When these reports started rolling in, researchers began experimenting on apple orchards, and so far have some conflicting data. One experiment in Washington found mite populations reduced when seaweed extracts were applied to the apples. However, in Vermont, another team found no difference in mite population but did report a reduction of maggots.

While the research remains inconclusive, many garden enthusiasts swear by it. Some claim that the timing of application is important, depending on where you are geographically and the type of pests you encounter.

Liquid seaweed is a common store item that can be used as fertilizer and pest control.

Further research into the mechanisms of these deterrents is needed. If conclusive, seaweeds could be an excellent organic pesticide for home or industrial use.

New review published on bioactive metabolites within seaweeds

A new review of bioactive metabolites in seaweeds was just published in Aquaculture. The review focused on carotenoids, polyunsaturated fatty acids, phycocolloids and sterols along with their chemical ecology.

Seaweeds are commonly harvested and consumed because of their high vitamin and antioxident content. However, secondary metabolites are widely used in the pharmaceutical and commercial sector for the production of algae derived phycocolloids like carrageenan, algin, steroids, lectins, agar, and carotenoids.

The review concluded that “seaweeds have a wide range of bioactive secondary metabolites which exhibits different pharmacological activity like anticancer, an-tifungal, anti-inflammatory, and antioxidant activity. The secondary metabolites obtained from the seaweeds are also widely used as healthier food ingredients in the manufacture of nutraceuticals throughout the world. The presence of diverse pharma-cologically effectual bioactive metabolites in the natural seaweeds makes it unique and indispensable in the identification of lead molecule for the new drug discovery.”

Pseudoscience in food health is extremely prevalent on the internet and social media. Rigorous studies and reviews on bioactives like these can help consumers separate true from perceived health benefits of their food.

New study examines the lipid profile of the sugar kelp (Saccharina latissima)

A recent study titled ”Polar lipid profile of Saccharina latissima, a functional food from the sea” was just published in the journal, Algal Research.

Saccharina latissima is a brown alga (kelp). It is known by the common name sugar kelp, and also sea belt or Devil's apron, due to its shape. Sugar kelp grows relatively fast and large (about 5 meters, or 16 feet long), and its ability to be grown on a long line also makes it an appealing species for near shore cultivation. Indeed sugar kelp farms have been on the rise within the USA.

The researchers examined all the lipids within sugar kelp important for either nutrition or other commercial use. They reported high levels of PUFAs (polyunsaturated fatty acids), such as the highly prized omega-3s, EPA and DHA that are typically sourced from fish oils. Western diets present high levels of omega-6 PUFAs, with a nutritional ratio omega-6/omega-3 greater than 2, which has been associated with increased risk of mortality due to cancer, cardiovascular, inflammatory and autoimmune diseases. However, marine macroalgae, such as S. latissima, present a much higher prevalence of omega-3 PUFAs than land vegetables. A diet rich in omega-3 PUFAs can reduce Omega-6/Omega-3 ratio, being nutritionally more healthful and contributing to the prevention of chronic diseases

Scientists sequence the genome of popular Japanese seaweed (Cladosiphon okamuranus) in preparation for climate change

Each year, thousands of tons of seaweed is harvested along the coast of Okinawa, Japan. However, scientists are warning that anthropogenic climate change will lower the annual yield and create a demand for new farming methods.

Researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) have sequenced the genome a popular brown seaweed, mozuku (Cladosiphon okamuranus). As pollution and rising temperatures changes the ocean, this data may provide critical information for local seaweed farmers.

“My future plan is to establish new methods for cultivation of this species,” said Dr. Nishitsuji. “Using those markers, we can do cross-breeding. This is a popular method for making new varieties of land plants, especially wheat and potatoes, but in the case of seaweed, no one has succeeded in cross-breeding.”

As the ocean changes, seaweed farmers will need these genetic tools to enhance breeding programs.

The study can be viewed here at Scientific Reports

Using macroalgae as an indicator of ocean conditions through time.

Researchers in Japan recently published a study in the Journal of Oceanography on using position-dependent radiocarbon as an indicator of oceanographic conditions during algal growth.

The macroalga Undaria pinnatifida grows in a predictable way, older growth at the top and the new growth is at the bottom (image below)

undaria_growth.jpg

The researchers hypothesized that the age of the Undaria tissue would correlate with ocean conditions through time. Inorganic carbon ∆14C was tracked in tissues and ambient water through time. The study concluded that inorganic carbon in the Undaria tissues did correlate with oceanic samples through time.

They concluded that this technique “provides a new tool to better understand the role of oceanographic conditions in sustaining coastal ecosystem productivity.”

It will be interesting to see this new approach applied to other species, such as Pterygophora californica, which can live upwards of 15 years.

Flexible Conductors from Brown Algae for Green Electronics

Researchers recently published about novel conductors in Advanced Sustainable Systems. What makes these conductors so novel is they are made from brown algae or kelps.

Alginate from brown seaweeds are are used to make a flexible sodium alginate film. Ultrathin gold layers are then added to the alginate film. The resulting foils are thin, easy to handle, and shape, while showing good conductive properties.

The researchers believe this novel use of sodium alginate conductors is a “very promising candidate to be employed in green electronics, thanks to the reduced energy consumption required for their fabrication, the absence of toxic components or chemicals that are derived from oil, and the possibility to disassemble the devices at the end of their life in environmentally friendly conditions.”

The research can be viewed here

Carrageenan extracted from red seaweeds could be used as an antifungal

A recent study, published in the Journal of Applied Phycology, assessed if carrageenan could be used as an antifungal.

Carrageenan is a sugar extracted from some red seaweeds that is commonly used in a variety of food products as a thickening agent. A previous post went into great detail about carrageenan traits, uses, and impact on human health.

The recent study examined kappa/iota carrageenan belonging to the gametophyte phase and a hybrid xi/theta carrageenan in the tetrasporophyte phase of Chondracanthus teedei  applied to a few species in the genus Alternaria. Alternaria species are known as major plant pathogens. They are also common allergens in humans, growing indoors and causing hay fever or hypersensitivity reactions that sometimes lead to asthma.

Carrageenan induced the formation of swollen hyphal segments upon exposure to as little as 125 and 60 μg mL−1. These results are similar as to those induced by antifungals targeting the fungal cell wall.

The researchers concluded that carrageenan from Chondracanthus teedei  causes physical alterations of the cell wall in Alternaria sp. indicating antifungal activity.