Red marine algae vs. kelp

Updated July 19, 2017

In recent years so-called superfoods have become increasingly popular, both to target specific illnesses and for overall health. Seaweed and sea vegetables are regularly cited as belonging to the group of superfoods, and are rich in vitamins, minerals, amino acids and other essential nutrients not found in land vegetables. Both kelp and red marine algae have distinct nutritive properties that may help with specific complaints as well as general well-being.


Kelp is a large seaweed that is actually a species of brown algae. Although green in colour, kelp is differentiated from the blue-green algae such as chlorella and spirulina, which also have proven health benefits. All are rich in chlorophyll. Chlorophyll is found in all plants, and is said to have a range of beneficial effects, such as anti-inflammatory. Chlorophyll is very similar in structure to the haemoglobin in blood, but carries magnesium rather than iron. Kelp is also rich in other minerals, such as selenium. Alternative heath practitioners such as Linda Page and Paul Pitchford strongly endorse the use of sea vegetables for their health-giving properties.


Kelp is known particularly for its high iodine content. Iodine is known to be a potent antifungal agent, and according to the author Paul Pitchford, has shown some effectiveness against yeast infections (candida). Iodine also affects the metabolism, having a direct action on the thyroid gland. An excess of kelp can lead to the potentially serious conditions of either hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid), and patients with thyroid disorders are warned against kelp consumption.

Red Marine Algae

Red marine algae is not so well known as kelp, but is increasingly sold as a health supplement. The red pigment in the algae are xanthophylls, of which some (e.g. lutein) have been shown to have certain health benefits. Certain varieties of red marine algae have been shown to be effective against asthma and cancer, as well as being valuable sources of dietary proteins, amino acids and essential fatty acids. Certain types of red marine algae have been shown to be effective against the herpes virus.


However, while kelp is just one of about 1,500 species of brown marine algae, there are around 4,000 species of red algae. The many different types of red marine algae contain different micronutrients, and although they are all sold in health stores as "Red Marine Algae," they do not all produce identical effects. The species Gigartina skottsbergii is one variety of red algae that has been shown to have antiviral effects against the herpes virus.


Marine algae are a valuable source of nutrients and may help cure many illnesses as well as improve overall health. However, there is a lack of clarity in the types of red marine algae on sale, and some species of algae such as kelp are known to have potential side effects (i.e. thyrotoxicosis). While judicious users can safely incorporate marine algae into their diet, there may be grounds for caution if taking mega-supplements.

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About the Author

Eve Roberts has written and published professionally since 1998. She has a PhD in humanities and has published articles in magazines, books and journals. She has worked in the health food and education sectors.