Every day we are exposed to a wide range of potentially harmful microorganisms – such as colds, flu and even COVID. But our immune system—the network of complex pathways in our body—helps protect us from these microorganisms and other potential diseases. Basically, it recognizes foreign invaders like viruses and bacteria and immediately takes action to defend us.
Humans have two types of immunity: innate and adaptive. Innate immunity is the body’s first line of defense, consisting primarily of physical barriers (such as the skin) and secretions—including mucus, stomach acid, and enzymes in saliva and sweat—that prevent microorganisms from entering the body. It also consists of cells that attack any foreign invaders entering the body.
Adaptive immunity is a system that learns to recognize a pathogen. It is regulated by cells and organs in our body such as the spleen, thymus, bone marrow and lymph nodes. When a foreign substance enters the body, these cells and organs make antibodies and multiply immune cells specific to this harmful substance to attack and destroy it. They also remember the pathogen for future reference.
There are many things we can do to support our immune system and even improve its function. Simple changes in your diet and lifestyle can play a big role in avoiding disease.
We are what we eat
The nutrients we get from the foods in our diet play a key role in building and maintaining our immune system.
Take the amino acid arginine for example. This is necessary for the formation of nitric oxide in immune cells, which is an important defense molecule against organisms. Vitamin A and zinc are crucial for the rapid reproduction of immune cells. Vitamin C contributes to immune defense by supporting the cellular functions of both immune systems. Similarly, vitamin E has been shown to enhance immune responses in animals and humans and provide protection against several infectious diseases such as influenza, COVID, and the common cold.
A varied diet including fruits and vegetables, whole grains, nuts, seeds, dairy products as well as fish, meat or plant protein alternatives will all contain these key nutrients that support our immune health.
The vast combination of microorganisms that live in our gut – known as our microbiome – also have significant effects on our health and well-being, despite their small size. In fact, the microbiome is often referred to as the “second brain” because of the extensive relationship it has with the organs and systems of the body.
One particular role played by the microbes in our gut is to support immune function. They help control inflammation, a process the immune system uses to protect itself from harmful pathogens. Ensuring a healthy microbiome can improve immune function.
There are many ways we can support our microbiome through the foods we eat. For example, research has shown that the Mediterranean diet, which is rich in vitamins, minerals and fiber, has an anti-inflammatory effect in the gut, which can help boost the body’s immune function.
This effect can be explained by a strain of bacteria known as Faecalibacterium prausnitzii which is key to immune regulation. This bacteria tends to be low in the Western diet but abundant in the Mediterranean diet. You should also avoid too much refined grains, sugars, and animal fats, which can increase inflammation in the body and weaken the immune response.
Probiotics (supplementary mixtures of live bacteria) may also have benefits. Research has even shown a probiotic blend of bacterial strains Lactiplantibacillus plantarumand and Pediococcus acidilactici reduced the amount of virus detected in the nose and lungs as well as the duration of symptoms in patients with COVID.
Your lifestyle can also have a big impact on immune function.
For example, smoking affects both innate and adaptive immunity, causing it to overreact to pathogens and reduce immune defenses. Alcohol has also been shown to increase susceptibility to both bacterial and viral infections. It does this by changing the way our immune system fights off infections. Even moderate drinkers can have lower immunity.
Sleep is also important for maintaining immune function. Studies show that frequent, poor sleep causes inflammation in the body. This can impair the immune response, increase the risk of infection, and make infections worse. Teens who only get around six hours of sleep are also more likely to suffer from common illnesses such as colds, flu and gastroenteritis.
Stress is another known factor that has a major impact on the immune system. It’s not just chronic stress that suppresses the immune system – even short periods of stress (eg an exam) can impair immune function. Fortunately, mindfulness meditation (which can help manage stress) may be beneficial to the immune system—although it’s not entirely clear why.
Exercise has also been shown to affect immune function, with research showing that moderate-intensity physical activity in particular (such as brisk walking or ballroom dancing) can improve the immune response. However, it’s important to find the right balance because long, intense exercise without enough rest between workouts can actually impair immune function and make you more likely to catch an infection. And according to some data, this decrease can occur after just 90 minutes of moderate to high-intensity physical activity.
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Of course, vaccination remains the best way to prevent infection from many common diseases, such as the flu. But a good diet and lifestyle—along with other precautions like washing your hands or wearing a mask—help support your immune system and the effectiveness of vaccines.
Samuel J. White, Associate Professor of Genetic Immunology, Nottingham Trent University and Philippe B. Wilson, One Health Professor, Nottingham Trent University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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