Anchovies: an introduction

According to the World Health Organisation (WHO), incorporating fish into your diet brings a variety of health benefits, such as anti-inflammatory support and reduced risk of cardiovascular disease.¹ This is due to their low fat content and high levels of beneficial proteins and micronutrients (vitamins and minerals).² They are also the primary source for the essential long-chain polyunsaturated fatty acid, known more commonly as omega-3.

Anchovies (Engraulis encrasicolus) are small saltwater fish that you’ll often find preserved in oil and packed into tins at the supermarket.³ Anchovies are enjoyed as food globally, being a notable mainstay of the Mediterranean diet.^3,4 This diet, by no coincidence, has been shown to be the best diet for directly and positively affecting the body’s immune system and intestinal microbiome.

In this article, you will learn how eating anchovies can give your immune system a boost in 3 key ways due to their rich nutritional profile. These 3 immunoregulatory mechanisms are:

• Immunoregulation and Anti-inflammation
• Antioxidant Effects
• Promotion of a Healthy Gut Microbiome

The basics of the immune system

Broadly speaking, the immune response is composed of two parts that work together to prevent and fight against infections from pathogens. Pathogens are germs such as bacteria, viruses, parasites, and fungi. The two parts of the immune system are the innate immune system and the adaptive immune system.

The innate immune system is your body’s first line of defence against pathogens. It is found in some capacity in all animals, and it has ancient evolutionary roots dating back around 1 billion years.⁵ 

The innate immune system consists of physical barriers like the skin and mucus, as well as specialised immune cells that are ready to act upon a breach in these barriers.⁶ Innate immune cells include macrophages, neutrophils, and natural killer (NK) cells. These cells act non-specifically, which means that they recognise and respond to a wide range of pathogens. Macrophages and neutrophils are part of a group of immune cells called ‘phagocytes’, whose role is to engulf invading pathogens to destroy them physically. NKr cells help to release proteins called chemokines and cytokines, which guide other immune cells into the area and activate them.

The adaptive immune system is more targeted than the innate one.⁷ It adapts itself to counteract and destroy specific invading pathogens that have been discovered by the innate system. It then provides long-term resistance over months or years by generating “memory cells”. Without this system, vaccines against infections such as influenza or COVID-19 would not work. 

The key adaptive immune cells are T cells and B cells, which are leukocytes (white blood cells) found in your blood. The primary function of B cells is to produce antibodies, which are proteins that bind to specific pathogens and opsonise (weaken) them. T cells are broadly categorised as CD4 T cells (“Helper” T cells) and CD8 T cells (“Cytotoxic” T cells), which provide cellular support and pathogen-killing functions, respectively.⁷

The call-to-arms from the innate response and the targeted pathogen-killing of the adaptive response leads to inflammation, which presents itself as redness, swelling, and heat around the infected area of your body.⁸ On the other hand, the regulation and resolution of these immune processes is called anti-inflammation.

Inflammatory and anti-inflammatory responses are both essential, and one cannot exist without the other. Eating anchovies as part of a balanced diet will provide your body with key nutrients that assist in maintaining the balance of the immune system and boosting its effectiveness.

Immune boost 1: immunoregulation and anti-inflammation

Anchovies are packed with nutrients that are essential for optimal immune system function and regulation by anti-inflammation, most notably zinc.⁹ Zinc directly supports the production and activation of phagocytes, leukocytes, and antibodies. It is also used as a catalyst for many of the proteins that are produced by and interact with immune cells, notably transcription factors (which transcribe genetic information from DNA).¹⁰ Humans and animals that are zinc-deficient show significantly-reduced antibody levels in the blood, which increases their susceptibility to infections and exacerbates symptoms, and is directly linked to increased mortality rates.11 Humans that are mildly Zinc-deficient present with constant mild inflammation and immune activation, which is dangerous when left unregulated12. The link between dietary Zinc and proper immunoregulation is so clear in fact that Zinc is considered one of the most essential nutrients in proper immune system functionality. Other such nutrients found in anchovies that assist with regulation and anti-inflammation, similarly to Zinc, are Magnesium and Vitamin B12.

Part of Zinc’s anti-inflammatory properties is as a signalling molecule within immune cells.¹³ Immune cells interact with each other and with pathogens a lot, through proteins such as cytokines and via receptors on their surfaces. When a cell receives information from the extracellular environment, signalling molecules pass this information into the cell and stimulate the appropriate response, such as the production of antibodies or triggering a self-destruct mechanism called apoptosis (a vital anti-inflammatory process). Signalling works in a cascade-like fashion, where the movement of one signalling molecule triggers the movement of others, and so on.¹⁴ Zinc has been shown to be an effective signalling molecule, but other main ones you get from anchovies are Calcium and Vitamin D.

Anchovies are one of the best ways to get essential “good” fatty acids into your diet, such as Omega-3. Similarly to Zinc, Omega-3 is also highly beneficial when it comes to immunoregulation and anti-inflammatory responses, particularly in the resolution phase of inflammation by interacting with enzymes that stimulate immune responses called COX-2 enzymes.¹⁵ However, Omega-3 also brings great antioxidant effects.

Immune boost 2: antioxidant effects

Oxidation is a chemical reaction that occurs when electrons move from one molecule to another, resulting in the production of substances called Reactive Oxygen Species (ROS; also known as free radicals) that are structurally unstable, highly reactive, and can damage cells and DNA.¹⁶ ROS are not always bad, and in fact can contribute to pathogen-killing and cell-signalling functions in the innate and adaptive immune responses.¹⁷ However, ROS levels need to be carefully maintained; otherwise, the immune system will destroy itself. The main method of ROS maintenance is through antioxidation.

Levels of ROS-induced damage to your cells are visible through the production of oxidative stress markers. Measuring levels of these stress markers is how scientists analyse the interplay between diet and oxidation, because the ROS themselves are too unstable and unpredictable to measure reliably.¹⁸ Omega-3 neutralises ROS by allowing them to oxidise the Omega-3 itself, thus reducing the potential damage that the ROS could cause elsewhere; this is known as scavenging.¹⁹ Omega-3 also directly encourages endothelial cells to produce less ROS by inhibiting enzymes that catalyse oxidation, notably Nox enzymes.¹⁹ Another antioxidant nutrient that you get from anchovies is Vitamin E, which has similar ROS-scavenging properties to Omega-3.²⁰

Selenium is a trace chemical element, like Zinc, found in anchovies, that has powerful antioxidant properties. Selenium is a key molecular building block of enzymes that contribute towards antioxidation in the body,²¹ and Selenium-deficient animal mouse models demonstrate over-production of ROS and decreased activity of immune cells to proliferate, communicate, and destroy pathogens.²² It is these antioxidant effects that mean dietary Selenium, Omega-3, and Vitamin E have the tangible benefits of reducing susceptibility to infectious diseases, heart disease, and cancer in humans.²²

Immune boost 3: promotion of a healthy gut microbiome

Inside the body’s intestines lives a microscopic world of organisms such as bacteria, fungi, and viruses, called the Gut Microbiome. The diversity between each person’s own Gut Microbiome is astounding, and there are still many of these microbes that have not yet been scientifically categorised.²³ Your individual Gut Microbiome is influenced by a range of factors, including genetics, lifestyle, age, and diet. Whilst everybody’s Gut Microbiome is unique, many of these microorganisms work together to perform broadly similar functions that contribute towards an individual’s health.²³ An imbalanced, unhealthy Gut Microbiome may lead to gastrointestinal, cardiovascular, and neurological conditions.²⁴

As of 2024, the interplay between the Gut Microbiome and the immune system is the subject of much interest in the scientific community. There is no doubt that a healthy Gut Microbiome has immune-boosting benefits, as 70-80% of immune cells are found in the intestines²⁵ and interact with microorganisms constantly. For example, these microorganisms stimulate T Cells to generate important inflammatory proteins, maintain the structural integrity of mucus and epithelial cells, which act as physical barriers, and outcompete invasive pathogens for nutrients needed for survival.²⁵

With diet being an important part of shaping your Gut Microbiome, eating anchovies can give your immune system a real boost, largely due to their abundance of the long-chain polyunsaturated fatty acid discussed already: Omega-3. The mechanisms through which Omega-3 benefits the Gut Microbiome are still being understood (although the link is clearly established) – but it seems the main benefit of Omega-3 is in maintaining the optimal ratio of Firmicutes to Bacteroidetes bacteria (two of the dominant microorganisms in the gut), as well as decreasing the levels of ‘bad’ bacteria that produce lipopolysaccharides (LPS, a dangerous bacterial toxin) such as Bifidobacterium.²⁴ By helping a healthy Gut Microbiome to flourish through the consumption of Omega-3-rich anchovies, you can improve your immune system’s capability to produce, activate, and maintain Innate and Adaptive immune cells in a regulated manner.

Summary

Anchovies are rich in nutrients that support and boost the functioning of your immune system. The most important nutrients discussed are Zinc, Selenium, and Omega-3, with a focus on how they impact 3 key areas of immune system support: immunoregulation and anti-inflammation, antioxidant benefits, and the promotion of a healthy Gut Microbiome. The mechanisms involved include interacting with innate and adaptive immune cells, scavenging unstable substances from oxidation reactions, and fostering a balanced ratio of beneficial intestinal microorganisms.

Whilst it is possible to take nutritional supplement tablets, there is the risk of accidentally overdosing and unbalancing your body’s homeostasis, which may be exacerbated in certain individuals such as pregnant women and those taking medication. Consult a Healthcare Practitioner if you are curious about taking supplements for Zinc, Selenium, Omega-3, or any other nutrient.

For a natural method of acquiring these immune-boosting nutrients, there are few more well-balanced sources than eating anchovies (in moderation). Anchovies are a great way to support your immune system and promote a healthy body.