Can Sharks Cure Cancer?

It has been long believed that sharks are immune to cancer, and that they hold the secret to curing it.

Sharks are fish with no bones. Their bodies are made up almost entirely of cartilage, which is a firm and flexible connective tissue that weighs less than bones and helps the animals swim faster. Scientists believe that sharks don’t get cancer because of their cartilage, and some people believe that shark cartilage has the ability to slow or stop the growth of cancerous cells in humans.

Since the publication of Dr. William I. Lane’s bestselling book Sharks Don’t Get Cancer: How Shark Cartilage Could Save Your Life in 1992 and the airing of 60 Minutes news segment showing a study of cancer patients in Cuba who had gone into remission after being treated with shark cartilage, worldwide interest in the treatment sky-rocketed. Even though the National Cancer Institute concluded that the results of the Cuban study were “incomplete and unimpressive,” shark cartilage pills have been promoted heavily as an alternative to conventional cancer treatments. However, studies since then have proved that these pills hardly work.

The idea that sharks don’t get cancer is a myth. While sharks have a low rate of disease, they are not entirely immune to getting sick, especially when they are exposed to toxins in the waters they inhabit. Perhaps the fact that most sharks spend their lives in some of the least contaminated areas on earth has a lot to do with their lack of disease, but that isn’t a good indicator of their cartilage being a cure for cancer.

The American Cancer Society states, “The consensus of available scientific evidence does not support claims that whole shark cartilage supplements are an effective treatment for cancer in humans.” It adds that while some experiments using shark cartilage have slowed the growth of new blood vessels in lab cell cultures and in animals, the effects on humans are unknown. In patients with advanced-stage cancers, a clinical trial proved that cartilage supplements had absolutely no effect.

Most of the shark cartilage products sold in the U.S. are dietary supplements that come in the form of pills and powders. These products have not been tested for their effectiveness and safety. They have also not been tested to find out how they interact with other medicines and foods. Although cartilage supplements are not drugs, and thus are free from FDA regulation, the Food and Drug Administration has fined and sometimes forced manufacturers to remove their products from the market for making false claims about the pills’ cancer-fighting abilities. According to the American Cancer Society, shark cartilage pills can affect liver function and slow the process of healing in people recovering from surgery. The pills are also not recommended for women who are pregnant or breast-feeding and those with seafood allergies.

Shark cartilage is taken from the heads and fins of sharks. The growing demand for cartilage pills is increasing the unnecessary killing of millions of sharks around the world. Shark populations are dwindling. The International Union for Conservation of Nature (IUCN) has already listed some shark species such as the hammerhead as endangered. North American populations of sharks have shrunk by 80% in the past decade. Since sharks take a long time to reproduce, overfishing is contributing to their rapid decline in numbers.

Sharks are amazing creatures. They’ve dominated our oceans for millions of years, since long before dinosaurs stepped foot on land, and they have survived five mass extinctions. Sharks are also vital to ocean eco-systems. As top predators feeding on the dead and dying animals, they help keep our oceans clean. Let’s hope there comes a day when these beautiful creatures are no longer exploited in the name of alternative medicine, especially one that doesn’t work.

You can help sharks by supporting conservation groups such as Ocean Conservancy and Shark Savers and urging lawmakers to restrict overfishing of shark populations.