Introduction

Maintaining a healthy diet, full of good fats and other nutrients, is key in protecting yourself against cardiovascular diseases. One such heart-healthy food is herring, a fish that is packed with essential nutrients and offers a delicious and effective means of protecting and improving heart health. This article will discuss how herring could benefit your health and how to incorporate it into your diet, as well as highlight any precautions and alternative options.

Overview: heart health

The cardiovascular system is made up of your heart and blood vessels, it pumps blood throughout your body, delivering oxygen and nutrients to your organs and tissues. To maintain a strong cardiovascular system, certain factors must be maintained, including healthy blood pressure, cholesterol, and blood lipid levels. This can largely be achieved by living a healthy lifestyle, for example, avoiding smoking and excessive alcohol consumption, eating a well-balanced diet, and exercising regularly.

If an individual develops high blood pressure (hypertension), high LDL (“bad”) cholesterol (hypercholesterolemia), or high lipid levels (hyperlipidaemia), it can lead to the development of, potentially life-threatening, cardiovascular diseases, such as:

• Coronary heart disease (CHD): a condition characterised by a narrowing or blockage within the coronary arteries, which supply oxygen-rich blood to the heart. This narrowing is often caused by a process called atherosclerosis, whereby fatty substances, known as atherosclerotic plaque, build up on the artery walls. This reduces blood flow to the heart, leading to chest pain (angina), shortness of breath, and in severe cases, heart attack
• Strokes or transient ischaemic attack (TIA): strokes are medical emergencies and can result in death. They occur when blood flow to the brain is disrupted, leading to neurological symptoms such as weakness, speech difficulties, and vision problems. They can result from blocked arteries (ischemic stroke) or ruptured blood vessels (haemorrhagic stroke). In comparison, TIAs, often called mini-strokes, are brief episodes of reduced blood flow to the brain, typically resolving within minutes to hours without causing permanent damage. However, TIAs are warning signs of increased stroke risk
• Peripheral arterial disease (PAD): a condition characterised by narrowing or blockage of the arteries outside the heart, most commonly in the legs. This narrowing reduces blood flow to the limbs, leading to symptoms such as leg pain, cramping, and weakness, especially during physical activity. PAD is often caused by atherosclerosis and is a significant risk factor for heart attack, stroke, and other cardiovascular complications
• Aortic disease, such as abdominal aortic aneurysm (AAA): is a condition characterised by the abnormal enlargement of the aorta, the main blood vessel that supplies blood to the abdomen. AAA typically develops slowly and without symptoms, and it often goes undetected until it ruptures, which can lead to severe internal bleeding and a medical emergency. Atherosclerosis and high blood pressure can increase the risk of this condition developing, by damaging and weakening the aorta walls

Although there is likely a genetic element to many cardiovascular disorders, genetic risks can be mitigated through lifestyle choices, for example, research shows that those who are genetically predisposed to hypertension can reduce their risk by 33% by following a healthy diet.¹

Herring’s role in heart health

Research consistently demonstrates the health benefits of eating fish. Herring is a type of fatty fish, which is exceptionally beneficial for heart health due to its rich content of unsaturated fats, particularly omega-3 fatty acids, called eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fats play crucial roles in maintaining cardiovascular health, reducing blood pressure, and promoting healthy cholesterol levels by supporting reverse cholesterol transport, the process in which excess cholesterol is removed from peripheral tissues and transported to the liver for excretion.^2,3,4

Herring is also an excellent source of protein, which is an important macronutrient for building muscle mass and maintaining a healthy body composition. Additionally, this fish contains various vitamins and minerals, such as:

• Selenium: a mineral with powerful antioxidant and anti-inflammatory properties. Selenium plays a crucial role in protecting thyroid, immune system function, and cells from oxidative damage. Adequate selenium may also help reduce the risks of cardiovascular disease
• Vitamin D: an important vitamin for maintaining healthy bones and teeth, and normal immune function. It is also thought to play a part in promoting cardiovascular health and mental health, with vitamin D deficiency being associated with instances of hypertension, cardiovascular mortality, and depression
• Vitamin E: a vitamin with antioxidant properties, which helps to maintain a healthy immune system skin, and eyes, as well as supporting cardiovascular health by preventing the oxidation of LDL cholesterol, which can contribute to atherosclerosis

However, it is important to note that vitamins and minerals are only required in very small amounts and excessive intake can have adverse effects, so they should only be consumed in moderation as part of a balanced diet.^5-17

Incorporating herring into your diet

Herring is a highly nutritious food and a great source of various heart-healthy fats, vitamins, and minerals. If you are considering introducing more herring into your diet, there is a wide array of simple and tasty options, some ideas include:

• Fresh, grilled herring: purchase fresh herring fillets, add olive oil (another heart-healthy ingredient), lemon juice, salt, pepper, chili flakes, or any other seasonings you desire. Grill until cooked through and slightly crispy on the outside. Serve with vegetables, such as green beans, and rice or potatoes
• Pickled herring: this is a common dish in many countries, such as Norway and Poland, and often involves pickling herring in ingredients, such as vinegar, salt, sugar, and other seasonings
• Smoked herring (kippers): hailing from the UK, kippers are a smoked form of herring, which take on a copper colour. They are traditionally eaten for breakfast, grilled with butter (however, you could switch this out for olive oil), and served with eggs

Be aware that some of these options can sometimes contain high levels of sodium, which can increase cardiovascular risk if consumed in excess, so it is important to eat in moderation.^18,19

Precautions and alternatives

When consuming fish, it is important to consider potential contamination by heavy metals, such as mercury, which has been linked to a wide range of health issues, including cardiovascular problems. This is particularly relevant in large, predatory fish, as they are more likely to contain higher concentrations of mercury. However, herring has low levels of mercury that many other types of fish.^20,21,22

Overall, herring is considered a relatively low-mercury fish and the average person should be able to safely eat in moderation, no more than once or twice per week. However, higher-risk individuals, such as young children and pregnant or breastfeeding women, should be cautious.²³

However, there are alternative sources of omega 3s, selenium, vitamin E, and vitamin D available for vegans, vegetarians, and those who simply prefer an alternative option:

• Omega 3s: these can be found in vegetarian sources, such as flaxseed oil, however, this provides alpha-linolenic acid (ALA), which has low bioavailability. The best sources of omega 3s contain EPA and DHA, as this is the most bioavailable form. Aside from fish sources, EPA and DHA can be found in algal oil. Therefore, a good vegetarian source of omega 3 comes in the form of algal oil supplments²⁴. Another benefit of algal oil is that it can be farmed in much more strictly controlled environments than fish, reducing chances for environmental contamination
• Selenium: this mineral can be found in meats, particularly organ meats, other animal sources, including eggs and dairy, and non-animal sources, such as Brazil nuts and grains²⁵
• Vitamin E: This vitamin is abundant in many non-animal sources, such as wheat germ oil, sunflower seeds, almonds, peanuts, and hazelnuts²⁶
• Vitamin D: this vitamin can be absorbed through sun exposure as well as through the diet. Some of the major dietary sources include eggs, mushrooms, and fortified milks²⁷

Summary

Herring has numerous health benefits, particularly for reducing cardiovascular risk. This is largely due to its high content of omega-3 fatty acids, which help to prevent atherosclerosis, along with various other vitamins and minerals, which have antioxidant, anti-inflammatory, and immune-supporting effects. However, like most fish, herring often contains mercury, which damages health, albeit in relatively low concentrations. Therefore, it is important to weigh up the pros and cons of eating herring for your health and keep in mind that alternative sources of these nutrients are available.