Gut Check

Seaweed: The Ocean’s Forgotten Gem

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We’ve all heard the term ‘superfood’ before. In reality, despite its fancy name, ‘superfood’ is more often than not simply a marketing term used for foods that are exceptionally rich in nutrients. However, even amongst all ‘superfoods’, one in particular is especially worthy of that title – a superhero among superheroes, if you will – and that superfood we are referring to today is seaweed.

Although seaweed may seem less attractive compared to other superfoods like salmon or avocado, it is in fact unique in terms of nutrient content. Seaweed is rich in vitamins and minerals like iron, but what makes it so special is the unique carbohydrates, such as alginate and fucoidan, that cannot be found in plants that are grown on dry land — seaweed is chock-full of them.

Moreover, seaweed is extremely rich in mineral salts, particularly potassium and magnesium. This is what gives seaweed its trademark, unmistakable salty taste without the excess sodium, making it a healthy alternative to common table salt.

Having said that, our focus today is on the interesting ways seaweed positively impacts the gut microbiome, consequently leading to health benefits in unique ways.

1. Boosting SCFA production

Seaweed has been shown to increase the capacity of your gut to produce metabolites known as short-chain fatty acids, or SCFAs. SCFAs play numerous roles in the body, such as regulating the immune system and improving gut and overall body health. SCFAs also help with reducing the risk of cancer and inflammation, and protecting the gut from infection.

Research has shown that, depending on what we eat, we can indirectly increase the SCFA production capacity of our gut microbiome, such as in the case of seaweed. In a study conducted in rats, it was found that subjects who were fed a diet containing whole seaweed or seaweed derivatives had a higher amount of SCFAs present in their caecum (a pouch connected to the junction of the small and large intestines) when compared to subjects who consumed a basal diet without any supplementation – an impressive 20% increase.

2. Altering gut microbiome composition

Research also shows that seaweed boosts the levels of Bifidobacterium, widely regarded as ‘good’ bacteria, in the gut. This group of bacteria helps to prevent diarrhoea and constipation while also reducing the risk of colorectal cancer.

Another study conducted in rats compared the effects of 3 different diets on the gut microbiome. The first diet was a basal diet consisting mostly of cornstarch, corn oil, and a mineral mixture; the second was the basal diet supplemented with carbohydrates found in fruits (fructo-oligosaccharides); the third was the basal diet supplemented with carbohydrates found in seaweed (alginate-oligosaccharides). The levels of Bifidobacterium in the rats under the seaweed group were found to be a whopping 13 times higher than that of the basal group, while also being 4.7 times higher compared to the fruit group. The boost in Bifidobacterium, as seen in rats, gives further evidence to support the proposition that eating seaweed has positive implications on our overall health.

While the results from these research studies seem to be overwhelmingly positive, seaweed consumption is not without any potential risks or restrictions. For example, seaweed contains a considerable amount of iodine which, if not consumed in a regulated manner, can lead to long-term thyroid problems.

All in all, these findings undeniably show us that superfoods, not just seaweed, can positively affect our health in more ways than just providing a large amount of nutrients. However, there is still much that is unknown to us for now. More research should be done to study the exact effects and mechanisms of how different superfoods can bring about changes to our gut microbiome and positively affect our health.

Why? Because with enough information, superfoods and diet could be the next frontier in precision therapy, and the key to unlocking a more robust, more natural control over human health.

Conlon, M., & Bird, A. (2014;2015;). The impact of diet and lifestyle on gut microbiota and human health. Nutrients, 7(1), 17-44. doi:10.3390/nu7010017

Charoensiddhi, S., Conlon, M. A., Methacanon, P., Franco, C. M. M., Su, P., & Zhang, W. (2017). Gut health benefits of brown seaweed ecklonia radiata and its polysaccharides demonstrated in vivo in a rat model. Journal of Functional Foods, 37, 676-684. doi:10.1016/j.jff.2017.08.040

O’Callaghan, A., & van Sinderen, D. (2016). Bifidobacteria and Their Role as Members of the Human Gut Microbiota. Frontiers in microbiology7, 925. https://doi.org/10.3389/fmicb.2016.00925

Wang, Y., Han, F., Hu, B., Li, J., & Yu, W. (2006). In vivo prebiotic properties of alginate oligosaccharides prepared through enzymatic hydrolysis of alginate. Nutrition Research, 26(11), 597–603. https://doi.org/10.1016/j.nutres.2006.09.015

About the authors

Nigel Lee is a final year student at Temasek Polytechnic studying Biomedical Science. He is currently interning at AMILI.

Bibi Chia is the Principal Dietitian at Raffles Medical Group. She is currently serving as AMILI’s dietetics advisor. 

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