Algae have been traditionally consumed in Asia for many years, and are now also gaining popularity in the West. Edible algae are a nutritionally dense food, containing a range of vitamins and minerals, phytochemicals and omega-3 fatty acids. Edible algae are often classified in three categories---Chlorophyta, Pharophyta and Rhodophyta, or green, brown and red. The different classes contain different levels of nutrients.
Vitamins
Algae are rich in the water-soluble vitamins thiamine, riboflavin, niacin, B6 and C. The first three vitamins are important in the conversion of foods into energy; vitamin B6 is essential in the metabolism of proteins and amino acids; and vitamin C, an antioxidant, is important in wound healing and collagen synthesis. Algae also contain the fat-soluble vitamin A, which plays important roles in vision, immune function and bone health. Brown algae tend to be the richest in vitamins and minerals.
Minerals
Algae are a rich source of iodine, potassium, iron and calcium. Iodine is a particularly important mineral, as apart from algae, the only other important source are fish and shellfish. Vegetarians and people who do not regularly consume fish are therefore at risk of iodine deficiency, and algae are an ideal substitute. According to "McCance and Widdowson's the Composition of Foods," dried algae often contain iodine at much higher levels than what's found in fish. Iodine is important for thyroid function, potassium helps to reduce blood pressure, iron is essential for healthy red blood cells, and calcium is the main mineral found in bones.
Omega-3
Omega-3 polyunsaturated fatty acids are a type of fat that have been associated with various health benefits including protection from heart disease, as reported in the June 2010 issue of "BMC Cardiovascular Disorders." The most effective omega-3 fats are Docosahexaenoic acid, DHA, and Eicosapentaenoic acid, EPA. The main source of EPA and DHA are fish and fish oils, as these fatty acids are not found in terrestrial plants. However, algae are a very good source of EPA and DHA, and in fact this is where fish get them in the first place. Supplemental forms of algal EPA and DHA are also available for vegetarians who want to increase their intakes.
Fiber
Like terrestrial plants, algae are a good source of fiber, a nutrient that can help in weight control, improves bowel health and protects against chronic illness, as reported in "Manual of Dietetic Practice." It has recently been found that a type of fiber---alginate----found in brown algae may be particularly effective in the management of obesity. In fact, the August 2008 issue of "Nutrition Research" reported that a 1.5 g dose of alginate may be enough to reduce the uptake of cholesterol and glucose in overweight male subjects.
References
- "McCance and Widdowson's the Composition of Foods: Summary Edition, 6th Edition"; Food Standards Agency; 2002
- "BMC Cardiovascular Disorders"; Omega-3 fatty acids in high-risk cardiovascular patients: a meta-analysis of randomized controlled trials; Fillion KB et al.; June 2010
- "Manual of Dietetic Practice, 4th Edition"; T. Briony and J. Bishop; 2007
- "Nutrition Research"; Alginate reduces the increased uptake of cholesterol and glucose in overweight male subjects: a pilot study; Paxman JR; August 2008
