Monday, October 14, 2013

Nutrition and the Immune System

Nutrition has been part of mankind's discourse since the dawn of time, and modern medicine equally emphasizes the role of proper nutrition as a key factor in maintaining healthy life.  Other than providing energy for the body's daily functions, nutrition plays an important role in the body's ability to protect itself. This article touches on several key points regarding the importance of proper nutrition to the immune system.

The Importance of Nutrition for the Innate and Adaptive Immune System
The human body's immune system consists of the innate and adaptive systems. The innate system is composed of different barriers – physical, chemical and microbiological – that provide immediate protection against harmful elements that invade the body. This protection is nonspecific, and targets any threatening element.
The adaptive system allows the body to "learn" the traits of harmful invading elements, and better protect itself against them. This protection is built with time and targets specific threats.
The following video provides further insight into the different mechanisms of the human body's immune system:

Both innate and adaptive systems work together against threats to the body, and the function of both is highly
influenced by nutrition. For example, both the phagocyte function of the innate immune system (the ability of immune cells to engulf and digest harmful elements), and the production of cytokine in the adaptive immune system (which is important for the body's immune responses), depend on proper nutrition.  Improper nutrition can impair the body's ability to block threats and adapt itself for better protection against them. Several cases of improper nutrition are considered particularly harmful to the immune system.
Malnutrition is considered to be one of the main factors behind immunodeficiency. Lack of elements such as protein energy can have negative effects on the thymus and the lymphoid tissue, both highly important for the function of the immune system, and lead to increased frequency and severity of infections. Malnutrition also leads to lack of omega-3 and omega-6 fatty acids that have shown positive effects on the immune system; the body does not produce these fatty acids, so their supply depends on nutrition.

The impairment of the immune system due to malnutrition makes the body more vulnerable even to treatable medical threats. For example, Dr. Adrian Gombart, Associate Professor of Biochemistry and Biophysics at the Oregon State University, who has studies cases of measles, noted in an interview that despite the availability of vaccine, measles is still "a major killer", mainly among children in developing countries, due to the lack of proper nutrition.

Eating Disorders and Obesity
Though the problem of malnutrition is commonplace mostly in developing countries, there are other nutrition-related issues that are common in developed countries that also influence the immune system. Studies of obesity cases have shown that obese people tend to be at increased risk of infection, and have poor antibody response – it is speculated that both problems are related to the effect of the metabolic process on the immune system. Studies of animal models have shown that obesity leads to a decrease in B-cells and T-cells, both major mediators of the adaptive immune system.
On the other side of the eating disorder range, anorexia nervosa patients have shown tendency to leucopenia, abnormal decrease in white blood cells, which are a vital part of the body's immune system.
Nutritional Advice for Strengthening the Immune System
During early childhood, breastfeeding is highly recommended, as it has proven to be an effective measure in preventing food hypersensitivity and other medical problems. Good dietary planning for older children (and adults) should consist of:
·         Variety of different foods.
·         Fruits and vegetables.
·         Low-fat dairy products.
·         Whole grain products.
·         Protein foods – preferably low-fat.
The following video by Dietitian Christine E. Marquette provides additional advices:

Build Your Immune System with Good Nutrition. Written by Dr. Janet Kurzynske, published by the University of Kentucky College of Agriculture.

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