In a recent review within the journal Food Science & Nutrition, a team of researchers summarized the present medical knowledge regarding the role certain common foods play in strengthening the immune system. The excellent article covered the advantages of consuming fruits, vegetables, spices, animal products, and other foods in maintaining a healthy immune system.

Study: Common foods for enhancing human immunity: A review. Image Credit: Danijela Maksimovic / Shutterstock

Background

The human immune system protects the body from pathogenic invasions. Humans are born with innate immunity (with cells resembling macrophages and neutrophils). Some immunity (resembling some sorts of white blood cells or lymphocyte cells) is acquired through exposure to pathogens. Nonetheless, scientists have known for a very long time that a healthy eating regimen is critical for maintaining and improving immunity. A dysfunctional immune system can result in issues resembling bronchial asthma, cystic fibrosis, and fibromyalgia.

Immune cells require sufficient energy to operate, while micro- and macronutrients maintain immune response. While the immunological function of specific nutrients resembling vitamins, minerals, and fibers has been reviewed in previous research, the immune advantages of specific food items haven’t been explored. On this review, the research team set out to deal with this gap, documenting commonly available foods that may boost immunity and construct resistance to disease.

Immune System and Nutrition

In humans, the immune response primarily comes from lively immunity, during which antibodies are produced throughout the body. Along with immune cells, other components include physical barriers resembling the skin, physiological barriers resembling saliva and stomach acid, and complement proteins.

Antibodies or immunoglobulins, that are produced because of exposure to pathogens, are classified as immunoglobulins A (IgA), D (IgD), E (IgE), G (IgG), and M (IgM). T and B lymphocytes, resembling suppressor T cells, killer T cells, and helper T cells, are instrumental in identifying, attacking, and eliminating pathogens. Organs resembling the spleen filter infections and abnormal cells within the blood, while glands can trap germs and other foreign materials.

Healthy lifestyle decisions resembling consuming a nutritious eating regimen, following an everyday sleep schedule, minimizing stress, and avoiding unhealthy habits resembling smoking can strengthen immunity and reduce the probability of affected by certain conditions.

Along with plant- and animal-based foods, water has a significant role in boosting immunity. Staying hydrated keeps mucous membranes moist, cells oxygenated, and various systems functioning. Toxins are carried to the kidneys after which the urinary tract before being expelled from the body, whereas dehydration may lead to them increase within the body and causing illness. Drinking sufficient quantities of water also can prevent urinary tract infections by stopping kidney stone formation.

Inadequate nutrient consumption can weaken the immune system’s development and render the body more vulnerable to allergies, infections, and chronic inflammation. This underlines the importance of adequate nutrition within the optimal functioning of the immune system. 

The researchers conducted a literature search on major scientific databases resembling PubMed, Web of Science, and Scopus to discover studies that focused on the immunomodulatory properties of common foods. These included peer-reviewed literature resembling research papers, meta-analyses, and systematic reviews.

Foods and nutrients that boost immunity

Citrus fruits resembling oranges and lemons are wealthy in vitamin C, which promotes the formation of lymphocytes, strengthens the body’s epithelial barriers, and functions as an antioxidant by reacting with free radicals, which may damage the immune system. Other useful compounds present in citrus fruits include selenium, dietary fibers, folic acid,  and flavonoids, that are antioxidative and anti inflammatory agents.

Papayas contain folic acid, retinol, riboflavin, thiamine, niacin, potassium, iron, fiber, and calcium. Carotenoids resembling beta-carotene might be converted to vitamin A and strengthen immune response, while retinoic acid promotes lymphocyte growth at infection and inflammation sites within the stomach.

Similarly, kiwis also contain vitamin C, K, potassium, carotenoids, fibers, and antioxidants; they’re anti-inflammatory foods that may reduce the danger of developing the flu. Pomegranate has antiviral properties and might suppress germs resembling Listeria, Clostridium, and Salmonella, while promoting healthy bacteria resembling Lactobacillus and Bifidobacterium.

Indian gooseberries contain a strong antioxidant called ellagic acid, while almonds are wealthy in vitamin E. Broccoli is wealthy in fiber and quite a few antioxidants, in addition to vitamins A, C, and E, phytochemicals resembling polyphenols, minerals, and vitamins. Ginger, along with being a promising immunomodulator, also enhances digestion and improves appetite, which may also be useful for the immune system. Garlic, turmeric, onion, mushrooms, and tea are also useful foods to incorporate in regular diets for a healthier immune system.

The role of animal-sourced foods (ASF)

A vital characteristic of ASF is that they contain easily digestible and high-quality proteins, essential amino acids, and micronutrients. Prolactin, a hormone present in milk, promotes lymphocyte and thymocyte movement; milk also comprises immunoglobulins and whey proteins, which stimulate the synthesis of antibodies.

Yogurt is analogous in composition to take advantage of, but calcium might be absorbed more efficiently from yogurt than milk. Along with proteins, vitamins, and minerals, eggs contain choline, which breaks down an amino acid called homocysteine, which has been linked to heart problems. Eggs are an inexpensive source of protein for many who cannot access pulses and dairy.

While medicine is critical in healing from health conditions, maintaining a nutritious eating regimen provides a primary line of defense against infection and illness. Incorporating whole foods and useful fruit, vegetables, dairy, and eggs can reduce the danger of developing various conditions and lessen their severity in the event that they do occur.