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Home Nutritional Supplements Spirulina & Kelp
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Spirulina and kelp
Spirulina & Kelp

Health enthusiasts are looking to the lakes and seas for algae and plant proteins that are powerful food supplements.  Spirulina and kelp have inspired hope as well as hype, but these aquatic plants do actually contain various beneficial substances.

What they are?

Spirulina and kelp are two very different types of aquatic algae.  The smaller of the two, spirulina (also known as blue-green algae) is actually a single-celled microorganism, or microalgae, that closely resembles a bacterium.  Because its spiral-shaped filaments are rich in the plant pigment chlorophyll, spirulina turns the lakes and ponds it grows a dark blue-green.  Kelp is another beneficial protector – one that comes from the sea.  Derived from various species of brown algae known as focus or Laminaria, this long-stemmed seaweed is a prime source of iodine, crucial in preventing thyroid problems.

What they do?

Spirulina and kelp have been used medicinally for thousands of years in China.  Their devotees make many claims – ranging from increased libido to reduced hair loss – but most of these remain highly speculative.  The algae do, however, have some confirmed powers.

Major Benefits

Because it is a prime source of chlorophyll, spirulina is ideal for combating one of life's most troublesome complaints: bad breath.  It can be an extremely effective remedy, provided the condition is not due to gum disease or chronic sinusitis.  Many commercial chlorophyll breath fresheners contain spirulina as a key ingredient.

The high iodine content of kelp makes it useful for treating an under-active thyroid that's caused by a shortage of iodine.  Kelp is also marketed as a weight-loss aid but it is probably effective only in the extremely rare cases when weight gain is secondary to an iodine-deficient, underactive thyroid.  For the treatment of thyroid disorder, it should be taken only under a doctor's close supervision.

Additional Benefits

Sometimes spirulina and kelp are included in vegetarian and macrobiotic diets.  Spirulina contains protein, vitamins (including B12 and folic acid), carotenoids and other nutrients.  In addition to iodine, kelp provides carotenoids, as well as fatty acids, potassium, magnesium, calcium, iron and other nutrients.  However, the concentrations of all these substances appear to be fairly low.  There are many less expensive – and better tasting – sources of vitamins and minerals than spirulina and kelp, including a range of common garden vegetables.

Various other claims are made for kelp and spirulina – that they boost energy, relieve arthritis, enhance liver function, prevent heart disease and certain types of cancer, boost immunity, suppress HIV and AIDS, and protect cells against damage from X-rays or heavy metals, such as lead.  But most studies on these supplements have been done in test tubes or with animals, and more research is needed.

Common Uses


  • Combats bad breath.
  • Adds proteins, vitamins and minerals to the diet.


  • Treats underactive thyroid.
  • Provides essential nutrients.


  • Capsule.
  • Tablet.
  • Powder.
  • Tincture.
  • Liquid.


  • Kelp may aggravate the condition of patients already taking medication for thyroid disorders.
  • Reminder:  If you have a medical condition, talk to your doctor before taking supplements.

How to take it?


To freshen the breath with spirulina:  Use a commercial, chlorophyll-rich 'green' drink (the label will often say if the chlorophyll is derived in part from spirulina) or mix 1 teaspoon of spirulina powder in half a glass of water.  Swish the liquid around the mouth, then swallow it.  Alternatively, chew a tablet thoroughly, then ingest it.  Repeat three or four times a day, or as needed.

To use kelp for an underactive thyroid:  Use only when recommended by your practitioner.  Powder forms dissolve easily in water, though some people don't like the taste.  Tablets, capsules and tinctures are equally effective.  fish may be a good option.

Guidelines for use:

Take with food to minimize the chances of digestive upset.  Pregnant or breast-feeding women may want to avoid kelp because of its high iodine content, though spirulina seems to be very safe.

Possible side effects

Occasionally, nausea or diarrhoea develops in those taking spirulina or kelp; if this side effect occurs, lower the dose or stop using it.  Up to 3% of the population is sensitive to iodine and may experience adverse reactions to long-term ingestion of kelp – including a painful enlargement of the thyroid gland that disappears once the kelp is discontinued.  This condition is most common in Japan, where seaweed is a dietary staple.

Facts and Tips

  • Don't harvest your own spirulina or kelp from the wild.  Coastal or aquatic colonies of the algae may be contaminated with industrial waste or sewage and contain concentrated levels of lead, mercury, cadmium, or other dangerous toxins.

Shopping Hints

    • Look for commercial breath fresheners that contain spirulina as one of the first listed ingredients.  Its rich chlorophyll content makes it a safe and effective natural way to freshen your breath.
    • Always check the expiry date on a packet of kelp, because the iodine content may decline with storage.  In one test, no iodine could be detected in kelp tablets that had been on a shelf for a year and a half.
    • Iodised salt has helped to relived many of the problems associated with iodine deficiency, such as goiter, but it's best to obtain your dietary requirements from natural sources of iodine.