Nutrition and immunity
During flu season or when people are sick, people often seek out special foods or vitamin supplements that are thought to boost immunity. Popular examples are vitamin C and foods such as citrus fruits, chicken soup and honey tea. However, the structure of our immune system is complex and depends on the right balance of many factors, not just diet and any particular food or nutrient in particular. However, a balanced diet of a range of vitamins and minerals along with healthy lifestyle factors such as adequate sleep, exercise and low stress levels prepares the body most effectively to fight off infection and disease.
What is our immune system?
On a daily basis, we are constantly exposed to potentially harmful microbes of all kinds. Our immune system, which is a network of complex steps and pathways in the body, protects us from these harmful microbes as well as from certain diseases. It recognizes foreign invaders like bacteria, viruses and parasites and takes immediate action. Humans have two types of immunity: innate and adaptive.
Innate immunity is the first line of defense against pathogens that try to enter our bodies through protective barriers. These barriers include:
- skin that protects against most pathogens
- mucus that traps pathogens
- stomach acid that destroys pathogens
- Our sweat and tears contain enzymes that help make antibacterial compounds.
- cells of the immune system that attack all foreign cells that enter the body
Adaptive or acquired immunity is a system that learns to recognize a pathogen. It is regulated by the cells and organs of our body like spleen, thymus, bone marrow and lymph nodes. When a foreign substance enters the body, these cells and organs produce antibodies and lead to the multiplication of immune cells (including various types of white blood cells) that are specific to this harmful substance. attack and destroy it. Our immune system then remembers and adapts to the foreign substance so that if it enters again, these antibodies and cells will be even more efficient and quick to destroy it.
other conditions that trigger an immune response
Antigens are substances that the body labels as foreign and harmful, which trigger the activity of immune cells. An allergy is a type of antigen and includes grass pollen, dust, food components, or pet dander. Antigens can cause a hyperactive response in which too many white blood cells are released. The sensitivity of people to antigens varies greatly. For example, a mold allergy causes symptoms of wheezing and coughing in a sensitive person, but does not cause a reaction in other people.
Inflammation is an important, normal step in the body’s innate immune response. When pathogens attack healthy cells and tissues, a type of immune cell called a mast cell retaliates and releases a protein called histamine that causes inflammation. The inflammation can cause pain, swelling, and fluid to help flush out pathogens. Histamine signals the release of even more white blood cells to fight off pathogens. However, prolonged inflammation can lead to tissue damage and suppression of the immune system.
Autoimmune diseases such as lupus, rheumatoid arthritis, or type 1 diabetes are partly hereditary and cause hypersensitivity, in which immune cells attack and destroy healthy cells.
Immunodeficiencies can suppress or completely disable the immune system and can be genetic or acquired. Acquired forms are more common and include AIDS and cancers such as leukemia and multiple myeloma. In these cases, the body’s defenses are so diminished that the individual becomes more susceptible to disease from invading pathogens or antigens.
What factors can inhibit our immune system?
- Aging: As we age, our internal organs may become less efficient; Immune organs such as the thymus or bone marrow produce fewer immune cells needed to fight infection. Aging is sometimes associated with micronutrient deficiencies, which can worsen weakened immune function.
- Environmental toxins (smoke and other particles that contribute to air pollution, excessive alcohol consumption): These substances can inhibit or suppress the normal activity of immune cells.
- Overweight: Obesity is associated with low-grade chronic inflammation. Adipose tissue produces adipocytokines, which can contribute to inflammation. [1] The research is preliminary, but obesity has also been identified as an independent risk factor for influenza virus, possibly due to impaired function of T cells, a type of white blood cell.
- Poor diet: Malnutrition or a lack of one or more nutrients in the diet can reduce the production and activity of immune cells and antibodies.
- Chronic diseases: Autoimmune and immunodeficiency diseases attack and potentially disable immune cells.
- Chronic mental stress: Stress releases hormones such as cortisol, which suppresses inflammation (inflammation is necessary to activate immune cells) and white blood cell activity.
- Lack of sleep and rest: Sleep is the body’s recovery time, during which a type of infection-fighting cytokine is released; Too little sleep lowers these cytokines and other immune cells.
Is there any diet to increase immunity?
Adequate nutrient intake as part of a diverse diet is essential for the health and function of all cells, including immune cells. Certain dietary patterns may better prepare the body for microbial attacks and excessive inflammation, but individual foods are unlikely to provide special protection. Each phase of the body’s immune response depends on the availability of several micronutrients. Examples of nutrients important to immune cell growth and function include vitamin C, vitamin D, zinc, selenium, iron and protein (including the amino acid glutamine). [3,4] They are found in a variety of plant and animal foods.
Diets that are limited in variety and low in nutrients, such as those consisting mostly of highly processed foods and lacking in minimally processed foods, can negatively affect a healthy immune system. It is also believed that a Western diet high in refined sugar and red meat and low in fruits and vegetables may contribute to disruption of healthy intestinal microbiota, leading to chronic intestinal inflammation and associated immune suppression.
The microbiome is the internal metropolis of trillions of microorganisms or microbes that live in our bodies, mostly in the gut. This is an area of intense and active research as scientists increasingly discover that the microbiome plays an important role in immune function. The intestine is the main site of immune activity and production of antimicrobial proteins. [6,7] Diet plays a large role in determining what types of microbes live in our gut. A fiber-rich diet rich in fruits, vegetables, whole grains and legumes supports the growth and maintenance of beneficial microbes. Some beneficial microbes break down the fibers into short-chain fatty acids, which have been shown to stimulate immune cell activity. These fibers are sometimes called prebiotics because they feed the microbes. Therefore, a diet consisting of probiotic and prebiotic foods may be beneficial. Probiotic foods contain live beneficial bacteria, while prebiotic foods contain fiber and oligosaccharides that nourish and support healthy colonies of these bacteria.
- Probiotic foods include kefir, yogurt with live active cultures, fermented vegetables, sauerkraut, tempeh, kombucha, kimchi and miso.
- Prebiotic foods include garlic, onions, leeks, asparagus, Jerusalem artichokes, dandelion greens, bananas and seaweed. However, a more general rule of thumb is to eat a variety of fruits, vegetables, beans and whole grains for nutritious prebiotics.
Chicken Soup as Medicine?
A bowl of hot chicken soup is a popular go-to when we’re not feeling well. Is there any scientific evidence that it helps in healing? The short answer is no; There are no clinical trials showing that chicken broth speeds up recovery compared to other foods. But if you break it down to its ingredients, it’s a really worthwhile remedy that’s worth a try. firstly, chicken soup is light and soothing to the stomach when we feel less hungry. Second, it provides the body with fluids and electrolytes to help prevent dehydration, which can easily occur with a fever. Finally, a traditional chicken soup recipe contains a variety of immune-boosting nutrients: protein and zinc from the chicken, vitamin A from the carrots, vitamin C from the celery and onions, and antioxidants in the onions and herbs. It’s a delicious and comforting food to eat when you’re not feeling well and doesn’t require a prescription.
Do Vitamins or Herbal Supplements Help?
Certain nutritional deficiencies can alter the body’s immune response. Animal studies have shown that deficiencies in zinc, selenium, iron, copper, folic acid and vitamins A, B6, C, D and E can alter the immune response. [8] These nutrients help the immune system in several ways: by acting as an antioxidant to protect healthy cells, by supporting the growth and activity of immune cells, and by producing antibodies. Epidemiological studies show that people who are malnourished are at greater risk of bacterial, viral, and other infections.
Vitamin D in the spotlight
Vitamin D’s role in regulating the immune system has led researchers to explore two parallel lines of research: whether vitamin D deficiency contributes to multiple sclerosis, type 1 diabetes and other so-called “autoimmune” diseases, In which the body’s immune system attacks its own organs and tissues? And could vitamin D supplements help boost our body’s defenses against infectious diseases like tuberculosis and seasonal flu?
Eating a good quality diet, as shown on the Healthy Eating Plate, can prevent deficiencies in these nutrients. However, there are some populations and situations in which a variety of nutritious foods cannot always be eaten or which have an increased need for nutrients. In these cases, vitamin and mineral supplements can help make up for nutrient deficiencies. Studies have shown that vitamin supplements can improve the immune response in these groups. [8-10] Low-income households, pregnant and lactating women, infants and young children, and the critically ill are examples of risk groups.
The elderly are at particular risk. The immune response typically declines with age because the number and quality of immune cells decline. This causes a higher risk of adverse outcomes if older people develop chronic or acute diseases. In addition, about a third of older people in industrialized countries suffer from nutritional deficiencies. [8] Some causes include loss of appetite due to chronic illness, depression, or loneliness; Many medications that can interfere with nutrient absorption and appetite. Malabsorption due to intestinal problems. and hypermetabolic conditions in acute or chronic conditions leading to increased nutrient requirements. Dietary variety may also be limited by budgetary constraints or low interest in single-person cooking; bad teeth; Mental Disorders; or the lack of transportation and public resources for healthy eating.
In these cases, a generic multivitamin/mineral supplement providing the Recommended Dietary Allowance (RDA) may be used unless directed otherwise by a physician. Supplementation at megadoses (in many cases exceeding the recommended daily allowance) does not appear to be advisable and may sometimes be harmful or even suppress the immune system (as with zinc). Remember that vitamin supplements should not be viewed as a substitute for a good diet because no single supplement has all the benefits of a healthy diet.
Herb
Several herbal supplements have been suggested to boost immune function. What does the study say?
- Echinacea: Cellular studies have shown that Echinacea can destroy the influenza virus, but limited human studies have failed to identify the active components of Echinacea. Taking echinacea after a cold has not been shown to shorten its duration, but taking it topically may offer a small chance of protection against a cold.
- Garlic: The active ingredient in garlic, sown allicin, is thought to have antiviral and antimicrobial effects on colds, but there are no high-quality clinical trials comparing garlic supplements to a placebo. A Cochrane review found only one trial of acceptable quality with 146 participants. Those who took a garlic supplement for 3 months had fewer colds than those who took a placebo, but the duration of illness after exposure to the common cold virus was similar in both groups.
- Tea Catechins. Cellular studies have shown that tea catechins found in green tea can inhibit influenza and some cold viruses from multiplying and enhance immune activity. Human trials are still limited. Two randomized controlled trials found that green tea capsules caused fewer cold/flu symptoms or flu morbidity than placebo; However, both studies were funded or affiliated with the tea industry.
8 Steps to Help Support a Healthy Immune System
- Eat a balanced diet with whole fruits, vegetables, lean protein, whole grains, and plenty of water. The Mediterranean diet is one option that includes these types of foods.
- If a balanced diet is not available, a multivitamin containing the RDA for several nutrients can be used.
- Don’t smoke (or quit smoking if you do).
- Consume alcohol sparingly.
- Do moderate exercise regularly.
- Try to sleep for 7-9 hours every night. Try to stick to your bedtime by getting up and going to bed at roughly the same time every day. Our biological clock, or circadian rhythm, regulates our feelings of sleep and wakefulness, so a consistent sleep schedule maintains a balanced circadian rhythm so we can get deeper, more restful sleep.
- Try to manage stress. It’s easier said than done, but try to find some healthy strategies that work well for you and your lifestyle, whether it’s exercise, meditation, a special hobby, or hanging out with a trusted friend. Another tip is to practice mindful breathing regularly throughout the day and whenever you feel stressed. It doesn’t have to be long – even a few breaths can help. If you need guidance, try this brief mindful breathing exercise.
- Wash your hands throughout the day: when entering from the street, before and after preparing and eating food, after going to the toilet, after coughing or blowing your nose.