Sea vegetables are becoming increasingly popular foods among health-conscious Americans, and for good reason.
- Are an excellent source of:
- Vitamin K
- Are a very good source of:
- Pantothenic acid.
- Measurable amounts of vitamins C and E
- A vast array of other minerals
- Measurable amounts of polyphenols, such as carotenoids and flavonoids
- Fiber (many sea vegetables)
- Omega-3 fatty acids (many sea vegetables)
Sea vegetables contain the mineral vanadium, which may have a role in bone growth. Several animal studies and a few very small human studies suggest that vanadium may lower blood sugar levels and improve sensitivity to insulin in people with type 2 diabetes. In one study of people with type 2 diabetes, vanadium also lowered their total and low-density lipoprotein (LDL) cholesterol. However, the dosages used in these studies were very large and the safety of taking this much vanadium is unknown. Some other studies have shown no relationship between vanadium and blood glucose.
Despite advertising efforts, there is no proof that vanadium is useful for athletic training. Supplements containing vanadium are reported to cause stomach pain, diarrhea, nausea, vomiting, and gas. Supplements are not recommended for people on blood thinners or people with high cholesterol, anemia, an infection, a low white-blood cell count, or kidney disease.
Sometimes referred to as sulfated polysaccharides, fucoidans are starchlike molecules found in sea vegetables, particularly brown algae. They seem to impart anti-inflammatory benefits and may have antiviral activity. In fact, studies have shown that sulfated polysaccharides prevent replication of herpes simplex 1 and 2.
Assays of the fucoidans obtained from the brown seaweed Adenocystis utricularis demonstrated that two of the five fractions analyzed had potent anti-HIV-1 activity because of a blockade of early effects of viral replication. They also seem to impart anticoagulant and antithrombotic properties. Fucoidans were shown in one study to block breast carcinoma cell adhesion to platelets, an effect which might have critical implications in tumor metastasis.
Some people believe that consuming sea vegetables may reduce the risk of estrogen-related cancers by reduction of cholesterol and the modification of women’s menstrual cycles. Research on colon cancer has found that sea vegetable extracts lead to a loss of calcium-sensing receptors in colon cancer cells. However, experts point out that because it appears that sea vegetables are anti-inflammatory and are a great source of antioxidants, it would make sense that they would help prevent a wide variety of cancers.
Classification of sea vegetables
Sea vegetables are classified as:
- Green algae, including sea lettuce
- Brown algae, including kombu/kelp, wakame, arame, and hijiki
- Red algae, including agar-agar and dulse
Tips for shopping and storage of sea vegetables
Follow these shopping and storage suggestions:
- Soak many types of sea vegetables for 5–10 minutes before cooking, but it is not necessary to soak some types, such as nori and kelp flakes
- Know that it is not necessary to cook sea vegetables before eating them
- Look for tightly sealed packages of sea vegetable when shopping, ones with no visible signs of excess moisture
- Store sea vegetables in tightly sealed containers at room temperature
Safety of sea vegetables
Unfortunately, sea vegetables absorb heavy metals, just as they absorb minerals. These metals can include arsenic, lead, and cadmium. It appears that arsenic is the biggest problem, and between 2000 and 2005, England, New Zealand, and Canada issued public health recommendations advising against consumption of hijiki sea vegetables unless they were verified as containing very low levels of inorganic arsenic. This is still a recommended practice, and you should seek out certified organic sea vegetables. Some packages will report lab testing on the packaging and indicate arsenic-free status.
References and recommended readings
Cumashi A, Ushakova NA, Preobrazhenskaya ME, et al; Consorzio Interuniversitario Nazionale per la Bio-Oncologia (CINBO), Italy. A comparative study of the anti-inflammatory, anticoagulant, antiangiogenic, and antiadhesive activities of nine different fucoidans from brown seaweeds. Glycobiology [serial online]. 2007;17:541-552. Available at: http://glycob.oxfordjournals.org/content/17/5/541.abstract. Accessed April 11, 2012.
George Mateljan Foundation. Sea vegetables: what’s new and beneficial about sea vegetables. Available at: http://whfoods.org/genpage.php?tname=foodspice&dbid=135. Accessed April 11, 2012.
Trinchero J, Ponce NM, Córdoba OL, et al. Antiretroviral activity of fucoidans extracted from the brown seaweed Adenocystis utricularis. Phytother Res. 2009;23:707-712.
University of Maryland Medical Center. Vanadium. Available at: http://www.umm.edu/altmed/articles/vanadium-000330.htm. Accessed April 11, 2012.
Review Date 4/12