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Introduction

Cartilage is a flexible part of connective tissue found between bones in the human body.

However, sharks have very different bone compositions and their skeleton is made up purely of cartilage.

Shark cartilage is now available as a dietary supplement and can be considered a powdered form of a shark’s skeleton.

This supplement has been studied as a treatment for a variety of medical conditions over the last 30 years, especially as an anti-cancer treatment.

Because manufacturers of cartilage products are not required to show evidence of anticancer or other biologic effects, it is unclear whether any of these products have therapeutic potential.

Some human studies have analyzed the effects of shark cartilage products, usually administered either topically or orally.

Shark Cartilage Health Benefits

Shark Cartilage May Protect Against Cancer

Shark cartilage was first theorized to be an anti-cancer treatment due an old idea that sharks were not affected by this disease [1].

A popular book was even published in 1992 titled ‘Sharks Don’t Get Cancer’. However, this theory has turned out to be false — sharks do get cancer.

Despite this, many people still believe shark cartilage can prevent cancer by either killing cancer cells directly, stimulating the immune system, or by blocking the formation of new blood vessels which tumors need for unrestricted growth (angiogenesis) [2].

However, these theories are based on weak, if any, real evidence. For instance, the idea that shark cartilage can inhibit the formation of new blood vessels is only based on the fact that cartilage does not contain blood vessels [3]. Hardly a ground-breaking scientific theory!

Other evidence suggests that the glycosaminoglycan component of shark cartilage acts as an angiogenesis inhibitor [4]. Glycosaminoglycans in cartilage may have anti-inflammatory effects and stimulate the immune system. It is proposed that these benefits may synthesize breakdown products that are toxic to tumor cells [5].

However, lab studies have actually shown that shark cartilage extracts can produce a proinflammatory response in human blood cells. This could pose a health risk for consumers, particularly those with an underlying inflammatory disease [6].

Based on the available evidence, shark cartilage should not be used as an anti-cancer treatment.

Shark Cartilage May Aid Joint Health

The type of cartilage derived from a shark is a type of connective tissue composed of chondroitin sulfate, protein substances, calcium, sulfur, and collagen.

In particular, collagen is the main structural protein found in connective tissues within human joints and is the most abundant protein in the human body.

Some research suggests collagen supplementation is a potential therapeutic agent for the management of osteoarthritis and maintenance of joint health [7]. Collagen supplementation is also thought to inhibit bone collagen breakdown [8].

Chondroitin is another major constituent of connective tissue and is the main glycosaminoglycan within cartilage.

Glycosaminoglycans provide an integral role for the structural and functional component of human joints. Supplementing with this substances can increase protein synthesis in cartilage cells and also reduce the production of pro-inflammatory molecules, thus reducing cellular death within connective tissue [9].

Some clinical studies suggest that chondroitin supplementation can even slow down joint space narrowing and cartilage degeneration, especially within elderly individuals [10].

However, it is key to note that the studies on collagen and chondroitin supplementation has not been sourced from sharks, and it should not be presumed that shark cartilage offers the same benefits. More evidence is needed to clarify this relationship.

Shark Cartilage Safety And Side Effects

There is a large safety issue regarding the intake of shark cartilage.

This supplement contains a neurotoxin called beta-methylamino-L-alanine (BMAA) that has been linked to neurodegenerative diseases such as Alzheimer’s.

The presence of this neurotoxin in sharks is because fish at the top of the oceanic food chain are the ones which continuously accumulate toxins in their system over time. This is explained by sharks consuming large amounts of sea creatures that feed on BMAA-containing algae – generating high concentrations of this toxin (transfer from prey to predator).

Interestingly, a study even found that brain samples of people that died from Alzheimer’s or Lou Gehrig’s disease had BMAA levels as high as 256 ng/mg, and some researchers hypothesize that toxins from fish may be a contributing factor [11].

Shark cartilage is found to have 144-1,836ng/mg of in seven shark species, including hammerhead, blacknose, nurse and bull sharks [12] – much higher than the expected concentrations in humans.

It is likely for this reason that the National Cancer Institute previously stopped their own research on shark cartilage supplements because when they found the preparations contained high levels of BMAA.

Reported side effects of shark cartilage include:

  • Altered taste perceptions
  • Nausea
  • Itching
  • Diarrhea
  • Constipation
  • Indigestion
  • Dizziness
  • Swelling of the hands and feet
  • Lethargy
  • Loss of appetite
  • Change in blood sugar levels

Conclusion

Shark cartilage is a dietary supplement consisting of powdered shark skeleton.

Many have claimed that shark cartilage may prevent the formation of cancer, and potentially aid in joint health by inhibiting collagen breakdown and increasing protein synthesis in cartilage cells.

However, shark cartilage contains a neurotoxin called beta-methylamino-L-alanine (BMAA) that has been linked to neurodegenerative diseases. For this reason, the consumption of shark cartilage is not recommended for use by any individual – at least until a lot more research has fully analyzed its safety.

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Fact Checked


This article has been reviewed and fact-checked by a certified nutritionist, and only uses information from credible academic sources.