Introduction

Mackerel is one of the top eleven fish species worldwide due to its content of omega-3 polyunsaturated fatty acids (ω-3 PUFAs), especially docosahexaenoic acid (DHA) and oleic acid. It is proven that applying PUFAs topically, taking it as a supplement or eating it as a part of the diet is beneficial. Its health benefits are especially seen in chronic cases, and typically those related to the joints, such as arthritis. Joint health is as important as the rest of one’s health; according to research, it increases health concordance with others around us and also improves our health.

Mackerel profile

The content of PUFAs in Mackerel fish is found to be 2.7-7.5 grams per meal, and according to the American Heart Association, these levels meet the recommended nutritional amount required per person. A high concentration of acids, such as palmitic acid, monounsaturated fatty acids (MUFAs), and oleic acid, were found in oils extracted from mackerel fish and study results have proved that the eicosapentaenoic acids (EPA), alongside other acid contents in mackerel, are believed to support and highly protect the nervous system. A new trial on “chub mackerel” proved that elevated levels of vitamin B12 and Selenium were found in chub mackerel compared to other mackerel species.

PUFA content differs from one species of mackerel to another; but they all contain a certain amount of PUFA, although may be of different levels. 

For example, the Atlantic mackerel contains:

• 0.1% linolenic acid
• 0.9% EPA
• 1.6% DHA
• 2.6% other PUFAs

 The oily mackerel contains:

• 1.7% EPA
• 2.9% DHA

For other “less oily” types of mackerel, there was found to be:

• 0.4% EPA
• 0.74% DHA

Results from both animal and human studies show that PUFAs have immunomodulatory importance. This means they have features enabling them to interact with many inflammatory conditions, including:

1. Crohn’s disease
2. Psoriasis
3. Ulcerative colitis
4. Asthma
5. Inflammatory bowel
6. Lupus
7. Cystic fibrosis
8. Rheumatoid arthritis

In cases of rheumatoid arthritis, mackerel supports immunity and lowers inflammation mediators resulting in:

• Significant decrease in early morning joint swelling and stiffness after 3 months of therapy
• Reduced progression of rheumatoid arthritis
• Reduced joint pain
• Reduced length of time to tire
• Increased strength
• Reduced use of non-steroidal anti-inflammatory drugs (NSAID)

Joint inflammation and Omega-3 fatty acid’s role in repair and maintenance of cartilage

In the United States, there are almost one million cases of individuals exposed to cartilage injury annually. This often leads to serious conditions and complications, increasing the rate of mortality in the worst-case scenario, and causing disabilities in the other.

Additionally, full restoration or treatment of these types of injury remains a huge therapeutic challenge, because of the limited self-regenerative ability of the articular cartilage. This low self-healing ability of cartilage is caused by how they are formed, which is described as multilayered, avascular, and abneural.

Rheumatoid arthritis is one of the most common autoimmune degenerative inflammatory conditions that is known to progress in the joints systemically. Many f cells are involved in the joint inflammation process. Some are, but are not limited to, B and T lymphocytes, macrophages and cytokines with chemokines, which are released causing hyperplasia, inflammation and damage to both bones and cartilage. Inflammation has been proven to be regulated by PUFAs, like omega-3 supplements. PUFAs, especially the two; DHA and EPA, which are found mainly in mackerel’s fats, are remarkable in reducing inflammation rates in cases of osteoarthritis.

PUFAs reduce inflammatory reactions by inhibiting the synthesis of chemical mediators involved in the inflammatory process. Omega-3 can relieve symptoms of arthritis, as well as other autoimmune diseases. Omega-3 plays a huge role in the reduction of pro-inflammatory cytokines levels with downregulation of damage to the bones’ cartilage or subchondral bone within the joints.

Omega-3 can work specifically by modifying the cell membrane to change its formation and function, while also interfering with various pathways. This mechanism of action leads to interactions with some pro-inflammatory chemical signals. Even the smallest amount of PUFAs, g can have a huge impact in the case of f arthritis. 

PUFAs also have an important role in reducing osteoarthritis progression. And preventing rheumatoid arthritis, specifically by improving the health and performance of muscles or by enhancing their metabolism and decreasing muscle atrophy. 

PUFAs, mainly EPA and DHA, can produce anti-inflammatory metabolites called resolvins that reduce inflammation. Omega-3 was tested on mouse models with rheumatoid arthritis, and it was discovered to decrease the plasma levels of inflammatory mediators. 2.4 grams of PUFAs per day in day, in arthritis, will produce increased levels of resolvins. This supports synovial fluid, decreases swelling, and reduces redness. These results have also been confirmed in humans.

Mackerel as the best source of PUFAs: A study

A recent study published in 2021, analysed a specific type of mackerel - the blue mackerel. This study described the lipid content of mackerel, looking at phospholipids and fatty acids. 

The exact distribution of the fatty acids, found in the by-product of the blue mackerel was measured by location, which were::

• Head
• Skin
• Roe
• Male gonad

The results showed that the roe, the mackerel's eggs, contained the most and the best source of Phospholipid and Omega-3 PUFAs (EPA and DHA), especially the N-3 Phospholipid.

The methods to concentrate PUFAs, and the importance of mackerel’s waste

Some of the ways to concentrate PUFAs are:

1. Solvent fractionation
2. Winterisation
3. Molecular distillation

Through these processes, EPA and DHA concentrations may reach up to 30%, whilst higher levels (up to 80%) may be possible through combinations of esterification, hydrolysis or fluid extraction. The lipid content of the waste ratio is (1.4: 40.1%), where oil concentration depends on the species. This explains how the waste of mackerel plays an important role in the source of PUFAs.

Summary

Mackerel’s PUFA content meets the recommended nutritional amount required per person daily. Studies have shown the important role of PUFAs in preventing rheumatoid arthritis, improving the health and performance of muscles or enhancing metabolism thus, decreasing muscle atrophy. Evidence highlights that increased intake of PUFAs will positively impact health.

Jean Carpentier, a nutritional columnist in the USA Weekend magazine, states that untreated injuries in athletes or any other individual may lead to complications. Carpentier not only highlights the importance of the daily consumption of food rich in different lipids and oils, but he also lists some anti-inflammatory foods, including mackerel, that are useful for diet and sports injury recovery.

Moreover, more studies are required to update the current guidelines for the United Kingdom, for the intake of Omega-3 PUFAs. This will ensure that individuals can receive every possible benefit they can.