High Iron Content and Bioavailability in Humans from Four Species of Marine Algae ,

Abstract

Searching for economical, nonconventional sources of iron is important in underdeveloped countries to combat iron deficiency and anemia. Our objective was to study iron, vitamin C, and phytic acid composition and also iron bioavailability from 4 species of marine algae included in a rice-based meal. Marine algae (Ulva sp, Sargassum sp, Porphyra sp, and Gracilariopsis sp) were analyzed for monthly variations in iron and for ascorbic acid and phytic acid concentrations. A total of 96 subjects received rice-based meals containing the 4 species of marine algae in different proportions, raw or cooked. All meals contained radioactive iron. Absorption was evaluated by calculating the radioactive iron incorporation in subjects' blood. Iron concentrations in algae were high and varied widely, depending on the species and time of year. The highest iron concentrations were found in Sargassum (157 mg/100 g) and Gracilariopsis (196 mg/100 g). Phytates were not detected in the algae and ascorbic acid concentration fluctuated between 38 microg/g dry weight (Ulva) and 362 microg/g dry weight (Sargassum). Algae significantly increased iron absorption in rice-based meals. Cooking did not affect iron absorption compared with raw algae. Results indicate that Ulva sp, Sargassum sp, Porphyra sp, and Gracilariopsis sp are good sources of ascorbic acid and bioavailable iron. The percentage of iron absorption was similar among all algae tested, although Sargassum sp resulted in the highest iron intake. Based on these results, and on the high reproduction rates of algae during certain seasons, promoting algae consumption in some countries could help to improve iron nutrition.

The iron content and ferritin contribution in fresh, dried, and toasted nori, Pyropia yezoensis

“…24) Together with the good bioavailability of iron in red alga Porphyra sp. (a native species of Venezuela), 15,16) nori can be considered as a good nutritional iron source. Since the dried and toasted nori samples were made from the raw thalli used in this study, these results reflect the true transition of iron concentration during the food processing.…”

“…However, the iron content values of preceding studies 17,18) tend to be lower (2-12 mg/100 g dry weight) 17) than that of the present results, available database, and another study measuring the iron contents in various algae, including red macroalga (Porphyra sp.). 15) To clarify the relationship between the grades of nori and iron contents, further encompassing study is required.…”

“…14) Garcia-Casal et al assayed the iron contents in several types of coastal macroalgae such as Ulva sp., Sargassum sp., Porphyla sp., and Gracilariopsis sp., which are classified as a green alga, a brown alga, and red algae (the last two species), respectively. 15,16) As a result, they have high iron contents compared with other food materials derived from plants, and all of them showed good iron absorption rates for human. 15,16) Traditionally, Japanese and people in other eastern countries have consumed coastal macroalgae as an indispensable ingredient.…”

“…15,16) As a result, they have high iron contents compared with other food materials derived from plants, and all of them showed good iron absorption rates for human. 15,16) Traditionally, Japanese and people in other eastern countries have consumed coastal macroalgae as an indispensable ingredient. Among the edible algae, susabinori or simply called nori (Porphyra yezoensis), red macroalga is one of the most important species, which is extensively cultured on the surface of coastal region in Japan, Korea, and China.…”

Effect of Use Fresh Macro Algae (Seaweed) Ulva fasciata and Enteromorpha flaxusa With or Without Artificial Feed on Growth Performance and Feed Utilization of Rabbitfish (Siganus rivulatus) fry

“…Ulva is a good source of protein, pigments, minerals and vitamins, and is especially rich in vitamin C [18,19] and, in recent years, Ulva species have become important macro algae, which have been investigated as a dietary ingredient for a wide range of fish species.…”