Chlorella is a single-celled freshwater alga that's also known by names such as sun chlorella, freshwater seaweed or green algae. The whole plant is used in making medicines and supplements, such as tablets, liquid extracts and powder. It's a popular treatment in Japan for a variety of health conditions, but there's not enough scientific research to support claims of its effectiveness in treating a wide variety of conditions such as colds, high blood pressure, high cholesterol and cancer.
The American Academy of Pediatrics has no official policy or any recommendations about the safety or effectiveness of chlorella for children, and chlorella gets no mention on medical websites such as those sponsored by Mayo Clinic, Cleveland Clinic and the National Institutes of Health. The American Cancer Society notes that most of the research on chlorella has been conducted in Japan, and the U.S. Food and Drug Administration has warned at least one website to stop making unproven claims about the benefits of chlorella.
Chlorella contains a lot of chlorophyll, which is the chemical that gives plants their green color. The alga is considered a good source of protein, fats, carbohydrates, fiber, vitamins and minerals. The supplement is widely used in Japan, but there has been limited scientific testing in the U.S. and there has not been enough independent testing to determine appropriate doses for adults and children. It's important to check with a doctor before using chlorella to figure out what may be a safe dose for you or your children.
Chlorella can produce a number of side effects, especially during the first week a child or adult is using it. Some of the common side effects include diarrhea, gas, nausea, stomach cramping and green stools. It has also caused allergic reactions, such as asthma and other dangerous breathing problems. People who take chlorella also may become more sensitive to the sun and increase their risk of sunburn. If you experience any allergic reactions while taking chlorella, contact a doctor immediately.
Anyone who is sensitive to iodine should be careful about using chlorella, as well as those with a weakened immune system or an immune system disorder. Chlorella may make the immune system more active, which could decrease the effectiveness of medications designed to suppress the immune system. People on blood-thinning medications should avoid chlorella. In addition, women who are pregnant or breast-feeding their children should not use chlorella. Little is known about the effect of chlorella for long-term use.