What Kinds of Natural Foods Improve the Human Immune System?

The immune system is the body's primary defense against bacteria, viruses, tumors and parasites. Consisting of the thymus, white blood cells, the spleen, lymph nodes and lymph channels, a properly functioning immune system must recognize its own tissues and cells. Autoimmune disorders, like Multiple Sclerosis and Rheumatoid Arthritis, occur when the immune system malfunctions and attacks its own tissues and cells. A healthy immune system is the first step to good health.

Foods with Soluble Fiber

Both soluble and insoluble fiber are important for good health. Insoluble fiber pushes food through the digestive system, aiding in regular bowel movements and elimination of toxic waste. However, soluble fiber not only reduces inflammation, but it strengthens the immune system according to Science Daily. Soluble fiber increases the production of interleukin-4, a protein with anti-inflammatory properties that energizes T-cells to fight infection. Oats, nuts, apples, oranges, carrots and flax seed are good sources of soluble fiber.

Foods High in Antioxidants

Antioxidants are vitamins, minerals and other substances that protect the body's cells from free radicals. Antioxidants work by stabilizing free radicals which are unstable molecules that damage and age cells and may cause cancer, according to the National Cancer Institute. Many foods are high in antioxidants, such as all berries, apples, plums and red grapes. Vegetables are also well-represented in the antioxidant arsenal with kale, broccoli, carrots, green pepper and spinach all being good sources.

Foods High in Vitamin D

The immune system requires Vitamin D, a fat soluble vitamin, to galvanize the body's disease fighting T-cells. Science Daily reports that without sufficient Vitamin D, T-cells will not gather an attack force against various pathogens. Produced when the skin is exposed to natural sunlight, Vitamin D is found in salmon, sardines, shrimp and eggs.

Foods with Probiotic Bacteria

Probiotic bacteria aid digestion and decrease the number of harmful bacteria living in the digestive tract. Found in dairy products, like yogurt and kefir, these "good" bacteria play a critical role in developing a healthy immune system, according to the National Center for Complementary and Alternative Medicine. The NCCAM also reports that probiotics protect the body from some disease causing microorganisms. When buying yogurt, look for products with active, live cultures.

Resources

• MedlinePlus: Autoimmune Disorders
• Agency for Toxic Substances and Disease Registry: Immunological (Immune System)
• ScienceDaily An Apple a Day? Study Shows Soluble Fiber Boosts Immune System
• National Cancer Institute: Antioxidants and Cancer Prevention: Fact Sheet
• Science Daily: Vitamin D Crucial to Activating Immune Defenses
• National Center for Complementary and Alternative Medicine: An Introduction to Probiotics