Chlorella is a so-called superfood that has earned a glittering reputation among its supporters as a fix-all supplement.

Chlorella is a single-celled, freshwater alga, native to Taiwan and Japan, that is naturally rich in proteins, vitamins, minerals, and dietary fiber. Its reported benefits include boosting antibody count, promoting weight-loss, and fighting cancer and other diseases.

There are various types of chlorella, each with different nutritional qualities. Those most commonly sold as food supplements are believed to have the highest nutritional value. Supplements are available as tablets, powder, or liquid extracts.

Chlorella's tough cell wall makes it rigid and impossible to digest in its natural form. It is processed before being sold so its nutrients can be properly digested.

Practical benefits include the fact that it grows quickly. Researchers have also looked at it as a possible alternative and renewable fuel source for agricultural equipment.

Alongside the nutritional content mentioned above, several studies have also suggested that chlorella has the potential to provide other health benefits.

Boosting the immune system

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Chlorella may help to reduce the risk of dementia, as well as reducing cancer risk.

Animal studies dating back decades have found that chlorella improved the ability of the immune systems of mice to fight against both bacteria and viruses.

A 2012 study was carried out to test the effects of chlorella on the salivary immune system of human subjects.

A total of 30 healthy people were given chlorella and studied over a 4-week period alongside 30 people who received a placebo. This trial was repeated 12 weeks later for another 4-week period on the same individuals.

The researchers found various positive and significant changes that suggested a strengthened immune system due to taking chlorella. However, the researchers recognized there were limitations to the study and suggested further testing was needed.

Protection against dementia

A 2009 study in mice found that chlorella played a significant role in preventing age-related mental decline. A big part of this seemed to be chlorella's antioxidant effects on the brain.

However, no human studies have been done to date.

Fighting estrogen-mimickers and reducing cancer risk

Estrogen is a naturally occurring hormone, important for the health of both men and women. There are certain estrogen-mimicking substances that can get into the body through contaminated soil, water, air, and other sources.

These mimicking substances are called xenoestrogens, and research has linked them to an increased risk of developing various types of cancer.

A 2005 study found that a laboratory culture contaminated with a xenoestrogen called BPA could be effectively treated with chlorella. In the study, the chlorella completely removed all of the estrogenic activity of the BPA from the culture.

While research needs to be carried out on animal and human subjects, chlorella may be able to reduce significantly the risk of cancers caused by estrogen-mimicking compounds.

The American Cancer Society have previously stated that there is a lack of scientific evidence showing chlorella is effective in fighting cancer or any other human diseases.

Anyone who wishes to take chlorella as a dietary supplement should be aware of potential risks from lack of oversight in its production.

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Chlorella supplements are available in liquid, tablet, or powder forms.

The exact balance of nutrients found in chlorella can vary a lot depending on the way it has been grown and processed, as well as the particular strain used.

A 2014 study found that chlorella treated with activated clay, to make it more suitable as a fuel source, lost over 70 percent of its fatty acid content. Chlorella sold in health stores should have a higher nutritional value than that being considered for fuel.

There is a lack of regulation over the safety and efficacy of supplements in the United States, however, so people should still use caution when purchasing from these retail stores.

Below are some of the nutritional benefits of chlorella.

Protein

Chlorella vulgaris, one of the most commonly used varieties, is up to 58 percent protein.

Chlorella protein is absorbed by the body almost as well as protein from eggs and milk. This is rare for plant protein sources and makes chlorella a great protein option for vegans.

Vitamin B-12

Chlorella is one of the few plant sources of vitamin B-12, as confirmed by a 2002 study.

A 2015 study found that B-12 taken from chlorella helped to improve the health markers of 17 vegans and vegetarians between the ages of 26–57 years old with a history of B-12 deficiency.

This result suggests that the body effectively absorbs the B-12 found in chlorella, making the alga a useful option for vegans and vegetarians with vitamin B-12 deficiency.

Iron

Chlorella is rich in iron and can stave-off an iron deficiency. One 2009 study found that a group of pregnant women given a chlorella supplement experienced significantly lower rates of pregnancy-associated anemia.

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Before taking supplements, it is important to ensure that they will not interact with any medication being taken, or any existing conditions.

People should be aware that every superfood could have a few potential risks and side effects associated with it. Unfortunately, chlorella is no different in this respect.

A 2003 study noted that green algae, such as chlorella, could become infected by viruses.

Some evidence has been found by researchers at Johns Hopkins University of these algal viruses infecting humans and leading to reduced mental functions.

A study dating back to 1996 found endotoxin-like properties in an extract of chlorella. Endotoxins are substances that are known to cause inflammation in humans when given in laboratory conditions. The effect depends largely on the size of the dose, however.

Chlorella is touted by its supporters as a highly nutritious dietary supplement that can make up for some of the nutrient deficiencies commonly experienced by vegetarians and vegans.

However, chlorella supplements are not regulated by the Food and Drug Administration (FDA) in the U.S. This leads to questions regarding efficacy and safety.

There is some early scientific evidence behind the claims that it might be able to improve mental function, boost immunity, and even reduce the risk of cancer. However, more studies on humans are needed to substantiate any of these claims.

One of the potential downsides to chlorella is that it may cause inflammation in some people, although the bulk of the evidence suggests otherwise.

If someone were to feel unwell while taking chlorella, they should stop immediately and consult a doctor. As there is no regulation of chlorella supplements, there is a risk of contaminants. For instance, a user might buy virus-infected chlorella and become infected.

As a dietary supplement, chlorella may have some benefits. However, given the lack of regulation in the production of these supplements, people should always use caution when taking them.