Green-lipped mussel: harnessing the power of marine ingredients
This popular nutritional component has been gaining traction in the pet supplement arena due to a belief in its anti-inflammatory properties.
As the focus shifts to a more holistic approach to pet care, the demand for high-value bioactive nutritional products is increasing. Is green-lipped mussel a contender for such multimodal therapy?
A short history
The green-lipped mussel (Perna canaliculus) is named after the green edges, or ‘lips’, to its shell and is indigenous to coastal New Zealand.
The health benefits of green-lipped mussels (GLM) have been studied since the 1970s, around the time commercial farming of GLM began. This interest was seemingly peaked by the observation that the indigenous Māori people of New Zealand (who have been eating green-lipped mussels for centuries) had a lower incidence of arthritis when compared with the people inhabiting inland communities.
Health benefits
GLM is currently used in some joint health supplements, due to its proposed effects on inflammation and cartilage repair.
Anti-inflammatory
Green-lipped mussel is high in certain omega-3 fatty acids that have anti-inflammatory properties, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Multiple studies have proven that these fatty acids offer a degree of protection against inflammation, osteoarthritis and cardiovascular disease in humans by modulating cellular signaling pathways. EPA and DHA are structurally similar to arachidonic acid and so can effectively compete as a substrate for enzymes in the pain pathway.
While oily fish also provides an excellent source of EPA and DHA, the omega-3 fatty acid eicosatetraenoic acid (ETA) is unique to GLMs, as is the nutrient profile. ETA is reported to possess stronger anti-inflammatory effects than other omega-3 fatty acids, although more research is needed here. Other important nutrients found in GLM include vitamins and minerals with antioxidant properties, such as vitamin C, zinc, magnesium, copper and selenium.
A review led by researchers at the Cawthron Institute in New Zealand showed that the vast majority of studies on dogs provide evidence that the addition of GLM extract to the diet can alleviate some of the symptoms of osteoarthritis. Some studies showed improvement in mobility after only 4 to 6 weeks of GLM supplementation. While this is certainly promising, it’s important to bear in mind that there is much variation in study design as well as the type of GLM extract used, and the results often rely on subjective assessment.
Heat processing can destroy the bioactivity of GLM, so careful processing techniques are required. A study published in 2013 in the Canadian Journal of Veterinary Research showed that low-temperature processed GLM powder was effective in reducing arthritic signs in dogs when incorporated into main diet or processed treats.
Chondroprotective
Green-lipped mussel also contains glycosaminoglycans, which form part of the building blocks of cartilage. It has been hypothesized that glycosaminoglycans may help to stimulate the production of cartilage matrix and inhibit the activity of enzymes that degrade cartilage. Some studies exploring this theory have shown that incorporating GLM into a complete diet can relieve some symptoms of arthritis in dogs.
Any side effects?
GLM is generally considered safe and there are no known side effects. However, as with all nutritional products, it’s important to consider the source and the quality. Mussels can be contaminated with heavy metals, pesticides and organic pollutants, for example.
Sustainability profile
Shellfish farming is considered one of the most sustainable forms of aquaculture. One study in a report from Aquaculture New Zealand showed that shellfish farming has a lower carbon footprint (per 100g of protein) than all other animal protein sources in New Zealand. Naturally, processing comes at an additional environmental burden, with drying of marine products and extraction of lipid fractions adding environmental and carbon costs.
Practicalities: addition to pet food
There’s a strong body of evidence for the benefits of adding GLM to the diet of dogs with osteoarthritis. The nutrients present in GLM may work synergistically to reduce inflammation and further cartilage damage, while supporting regeneration of cartilage and synovial fluid.
Furthermore, the evidence is promising, and continually mounting, for the more widespread benefits of omega-3 fatty acids – and GLMs offer an excellent source of these. While the evidence is currently limited for the benefits of the other nutrients, the wide safety margin makes GLM an excellent choice of nutraceutical.
Reducing reliance on medication
While studies on GLM products have mostly been promising, they don’t show the same efficacy as non- steroidal anti-inflammatory drugs. However, they may reduce the need for conventional medication and may even offer a gastro-protective effect, making them ideal for use alongside conventional medication. In fact, a great number of dog owners are already feeding their dogs joint supplements containing GLM, indicating that diets already enriched with GLM could prove very popular and convenient.
Given the source, harvest method, manufacturing process and dose of GLM could all affect the concentration of key bioactive compounds, more randomized, controlled and non-subjective clinical trials are needed in pets. This could serve to further prove the benefits of GLM and determine optimum formulation and dosing.
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