By Syed S. A.
Reviewed by Danielle Ellis, B.Sc.
Over the past few decades, algae have shown significant potential as a reservoir for diverse bioactive compounds possessing various biological activities. This has expanded their use across a range of industries, including food, animal feed, cosmetics, pharmaceuticals, and other industrial sectors.
Image Credit: catalina.m/Shutterstock.com
Image Credit: catalina.m/Shutterstock.com
From Spirulina to Seaweed: How are different types of algae integral to human diets?
Algae are photosynthetic aquatic creatures that grow through the consumption of nutrients, light, and carbon dioxide. They are a diverse group of creatures that include tiny single-celled algae and enormous kelp, as well as seaweed 1. Numerous prokaryotic and eukaryotic algae species are desirable as food sources for humans due to their inherent qualities 2,3.
Human intake of macroalgae such as seaweed and microalgae like phytoplankton dates back many years. Multicellular macroscopic aquatic plants, or macroalgae, are classified into three taxa: Phaeophyceae, or brown algae, Rhodophyta or red algae, and Chlorophyta or green algae. Microalgae, the unicellular counterpart of macroalgae, are categorized in a broader framework that includes prokaryotic cyanobacteria (blue-green algae), Euglenophyta, and Chlorophyta, which are genetically distinct from one another.
The ancient populations of Chad and the Aztec culture were already familiar with the cyanobacteria spirulina, which is currently advertised as a superfood in the West 4. In Burma, Vietnam, and India, other cyanobacteria/microalgae, like Spirogyra and Oedogonium, were eaten as food or as a supplement 4. Seaweed is a staple of daily meals in many Asian and Pacific civilizations, including Korea, Japan, and Indonesia, as well as Hawaii and New Zealand 5.
Nutritional profile of algae-based supplements
Algae provide a wide range of nutrients that are beneficial for health, including protein, sterols, and vitamins. Numerous health-promoting characteristics, including antioxidant and anti-proliferative actions in relation to algal phenolic and flavonoid concentrations, have been shown by scientific research 6-9. Produced for both humans and animals, algae and microalgae are often rich sources of fats (especially omega-3 fatty acids and carotenoids), carbohydrates, minerals, enzymes, hormones, and colors 10.
Health benefits supported by science
Algae have been shown to have multiple health benefits, including the ability to combat microbiological infections, hypertension, obesity, and diabetes, owing to their complex nutritional composition. As a result, the market for nutraceuticals generated from algae is growing quickly in the food supplement industry. A major factor in this has also been the idea of algae prebiotics and how they affect the gut microbiota 11.
Phlorotannins, polysaccharides like fucoidans, laminarins, alginates, carotenoids like fucoxanthin, and sterol–fucosterol are examples of bioactive substances found in algal species. They have demonstrated strong antidiabetic potential 11. Phloroglucinol, dieckol, and eckol are examples of marine algae that contain phenols 12. Ecklonia stolonifera, a brown alga, also contains them in ethanol extract, hexane, and aqueous fractions. These extracts have an inhibitory effect on the enzyme aldose reductase 13.
Algae have a lot of bioactive components, along with a lot of dietary fiber and nitrate, which is what causes the hypotensive impact and lower blood pressure 14. Algae have a variety of uses, one of which is their ability to lower blood pressure.
Some macroalgal peptides can hypotensively affect the human circulatory system and support a healthy heart by warding off deadly conditions like peripheral vascular disease and atherosclerosis 15. Positive outcomes for treating obesity have been demonstrated by macro and microalgae 14.
Important bioactive substances present in algae, including indole derivatives, fucoidan, fucoxanthin, phlorotannins, and fucosterol, have been demonstrated to play a function in digestion and are thought to have therapeutic potential for obesity 16.
Algae in specialized diets
Algae, with their high nutritional quotient, can become an important component of vegan and vegetarian diets. For example, In comparison to beef, which has a protein content of 22%, spirulina boasts an exceptionally high protein content ranging from 60% to 70% of its dry weight. It has twice as much protein as the best protein source that can be found in vegetables. Compared to the percentages in fish and meat from animals (15–25%), soybeans (35%), and eggs (12%), this number is much larger 17.
Image Credit: TarikVision/Shutterstock.com
Image Credit: TarikVision/Shutterstock.com
Furthermore, compared to the technique of obtaining enzymes from vegetables, the process of obtaining proteins through proteolytic enzymes is simple, and its protein digestibility ranges from 85% to 95% 18. It has been fortified with vitamin B12, an essential nutrient that is scarce in a vegetarian or vegan diet as it is exclusively present in animal sources 19.
Safety, quality, and sustainability considerations
Nutrient utilization has a significant role in the sustainability of food production in both traditional agriculture and algae farming. Fertilizers can supply the necessary combination of nitrogen, phosphorous, and potassium for the growth of algae as well as conventional crops. The Haber-Bosch method is used to create the majority of synthetic nitrogen fertilizers from atmospheric nitrogen 20. Unfortunately, because it relies on fossil fuels and significant CO2 emissions, this process is very energy-intensive and has environmental problems 21.
The growing popularity of algal biofuel production as a substitute for fossil fuels, which play a significant role in climate change, can be attributed to their efficient sequestration of CO2 into lipids that are high in energy 22. Other sustainable biofuel sources are less environmentally friendly because they take more energy to convert biomass into biofuels 23. While the core process of producing biomass will remain the same, the downstream processing required for producing algae biomass for food or feed will differ from that required for producing biomass for biofuel 24.
Challenges and misconceptions
Although there has been a little increase in the switch to alternative protein sources, there is still a long way to go before algae is widely accepted as a novel, healthful food source. This will mostly rely on various marketing techniques to educate the public about the health advantages these organisms can offer 1.
Enhancing microalgae growth rate and product synthesis, pretreating biomass, dewatering algae culture for biomass production, and improving the fermentation process in the case of algal bioethanol production are the most difficult and important problems 23.
Future trends and research
Current innovations in genetic engineering, breeding, and selection can all help algae produce more biomass and nutrients. The process of domesticating algae and producing strains with the desired characteristics has taken millennia to develop in traditional agricultural plants.
However, there is still much work to be done in this regard. Studies measuring the resource requirements and environmental effects of algae grown for human consumption are currently lacking.
Algae can play a major nutritional role in people’s meals and contribute to a more environmentally sustainable future if cultivation methods and production efficiency are refined via additional research 1.
Understanding the complexities of combining fundamental research with clinical trials and legal regulations to produce marine food products is one of the challenges confronting algae scientists. However, the most significant breakthroughs will necessitate a reconsideration of experimental and cooperative methods, and the drive for this study will only intensify as human demands on the climate system force us to go more and more to the oceans for sustainably harvested and grown food 2.
Conclusion
Protein, sterols, and vitamins are just a few of the many health-promoting substances found in algae. Numerous health benefits have been demonstrated by them, such as their capacity to fight diabetes, obesity, and hypertension. Owing to their high nutritional content, they can play a significant role in a vegan or vegetarian diet. There has been a slight increase in the use of alternative protein sources, but widespread acceptance of algae as a novel, beneficial food source is still a long way off. If growth techniques and production efficiency are improved via greater research, algae can be a significant nutritious component of people’s diets and help create a future that is more environmentally sustainable.
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