Brown seaweed is a nutritious superfood that's been a part of the traditional diets of many Asians. Sometimes referred to simply as kelp, this family of underwater algae can be seen by the naked eye (macroalgae) and are capable of photosynthesis, just like plants on land.
Numerous studies have linked the consumption of brown seaweed to a variety of health benefits. Seaweeds in general are a great source of essential nutrients, having 10 times the amount of minerals found in plants that grow in soil. Because of this, people who regularly consume seaweed rarely suffer from mineral deficiencies.
Studies have found that seaweeds have the unique ability to absorb and concentrate certain substances from seawater. For instance, kombu, the tough, leathery, dark-brown seaweed often used in Japanese cuisine, has been reported to have 30,000 times the concentration of iodine as the surrounding seawater. Many different types of kelp also contain up to 30 times higher concentrations of potassium.
Aside from minerals, seaweeds contain an abundance of soluble and insoluble fiber, which humans need to maintain a healthy digestive system. Soluble fiber feeds the good bacteria in your gut and is said to help reduce fat absorption, lower blood cholesterol and stabilize blood sugar levels. Insoluble fiber, on the other hand, helps prevent intestinal blockages and promotes regular bowel movement.
Other health-supporting compounds found in brown seaweed include polysaccharides, proteins, polyphenols, phytosterols, polyunsaturated fatty acids (omega-3s) and carotenoids. Among these, the carotenoids in brown seaweed, specifically the xanthophyll, fucoxanthin, have attracted the interest of researchers for their beneficial effects.
Aside from having antioxidant, anti-inflammatory, anti-obesity and antidiabetic properties, fucoxanthin has been found to have potent anticancer activities, making it a promising natural compound for cancer therapy.
Fucoxanthin from brown seaweed can suppress the growth of different types of cancer cells
Fucoxanthin is an accessory pigment and the major carotenoid found in the chloroplasts of brown seaweed. A powerful antioxidant and free radical scavenger in its own right, fucoxanthin can also enhance the activity of antioxidant enzymes. Animal studies have shown that fucoxanthin can suppress inflammation by reducing the expression of pro-inflammatory chemicals.
Carotenoids like fucoxanthin are absorbed in the intestine in the same manner as dietary fats. Once ingested, fucoxanthin is broken down by digestive enzymes into fucoxanthinol. In cell culture studies, both fucoxanthin and fucoxanthinol have shown the ability to inhibit the proliferation of prostate and colorectal cancer cells, with fucoxanthinol being slightly more potent than its precursor at lower concentrations.
In a recent study published in the International Journal of Molecular Sciences, French researchers looked at existing evidence of fucoxanthin's anticancer activities and enumerated the different mechanisms underlying its beneficial effects. They noted that fucoxanthin can effectively stop the growth of different types of cancer cells by:
Interrupting the cell cycle
The cell cycle is a series of events that occurs in cells which allow them to grow and divide. Studies show that fucoxanthin halts cancer cell cycle progression at the interphase, where cells are said to grow, replicate their chromosomes and prepare for cell division.
Fucoxanthin has been shown to work via this mechanism on leukemia, Burkitt lymphoma, Hodgkin's lymphoma, bladder cancer, melanoma, gastric cancer, colon cancer, prostate cancer, neuroblastoma, liver cancer, cervical cancer and bone cancer cells.
Inducing apoptosis and autophagy
Apoptosis is a form of programmed cell death that occurs naturally as a component of normal cell turnover. This process is also a normal part of development and aging and is even used by the body as a defense mechanism to eliminate damaged cells.
Autophagy, meanwhile, is a process by which cells destroy old, damaged components, such as abnormal proteins and other biomolecules. Cells then recycle these broken-down components for use in important cell functions during times of stress or starvation.
According to the French study, fucoxanthin and its metabolite, fucoxanthinol, can induce apoptosis in cancer cells by triggering the excessive production of free radicals called reactive oxygen species and suppressing the expression of apoptosis inhibitors.
Several reports have also noted that fucoxanthin-induced autophagy often precedes apoptosis, suggesting that autophagy could be a promoter of apoptosis in cancer cells. Fucoxanthin has been shown to reduce the viability of gastric cancer cells by inducing both autophagy and apoptosis.
Suppressing angiogenesis
Angiogenesis is the process by which new blood vessels are formed. This process is vital to the growth of tumors and cancer cells because the new blood vessels give them access to more nutrients and oxygen from the blood. Tumor/cancer cells are known to release chemicals that promote angiogenesis.
Multiple studies have shown that fucoxanthin and fucoxanthinol can inhibit angiogenesis, effectively stopping the growth and proliferation of breast cancer cells. Fucoxanthin's anti-angiogenic effect has also been shown to suppress the growth of malignant tumors.
Causing DNA damage
As a potent antioxidant, fucoxanthin can protect cells from oxidative damage caused by free radicals. Fucoxanthin has also been found to reduce DNA damage caused by exposure to ultraviolet rays.
But researchers have proposed a novel way of using fucoxanthin for cancer therapy: reducing the viability of cancer cells by damaging their DNA with high enough concentrations of fucoxanthin.
One Japanese study successfully augmented DNA damage in leukemia cells by treating them with fucoxanthin and fucoxanthinol, causing the cells to undergo apoptosis. They observed a similar effect in breast cancer, colorectal cancer and colon cancer cells.
Interestingly, fucoxanthin proved to be selective for cancer cells and remained non-toxic to normal cells, even at concentrations where it showed anticancer activity. This shows the huge potential of this seaweed compound as a novel and relatively safe natural treatment for cancer.
Fucoxanthin also has antidiabetic and anti-obesity effects
In addition to fighting cancer, fucoxanthin from brown seaweed can help reduce body weight and blood sugar levels. Studies show that fucoxanthin's anti-obesity effects may be related to its upregulation of mitochondrial UCP1, a protein that promotes fat-burning.
UCP1 is normally found in brown adipose tissue, the type of body fat that helps burn calories by generating heat (thermogenesis) to regulate your body temperature. Fucoxanthin has been found to increase the expression of UCP1 in white adipose tissue, the type of fat linked to obesity. This not only increases mitochondrial respiration (cell metabolism) but also promotes the burning of fat for energy.
While increasing UCP1 in white fat cells, studies show that fucoxanthin can also decrease their expression of pro-inflammatory signaling molecules. These molecules are believed to contribute to insulin resistance, Type 2 diabetes and cardiovascular disease. By improving the sensitivity of cells to insulin, fucoxanthin promotes cell uptake of glucose from the blood, which helps lower blood sugar levels.
Because of these beneficial effects, researchers believe that fucoxanthin from brown seaweed can be used for the prevention of obesity, diabetes and metabolic syndrome.
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