Defining a “cold” is difficult. Many symptoms of a cold, such as nasal congestion, fever, chills, sneezing, muscle ache and weakness are common symptoms of other conditions, like influenza, sinus infections and allergies. Technically, colds are caused by viruses, but bacteria, fungi and toxins can create similar symptoms. Thus, there are no valid scientific studies that prove anything can prevent colds, but logic dictates that a strong immune system can thwart infectious diseases and certain vitamins are essential components of a strong immune system.
Vitamin A is essential to the defensive component of the immune system. Although better known for contributing to healthy vision, vitamin A helps keep viruses and other microorganisms from penetrating the body by maintaining mucus membranes. With the aid of vitamin A, mucous membranes that line the nose, sinuses, mouth, throat and intestines remain moist and evenly distributed, and function to trap and eliminate potential pathogens. Vitamin A also contributes to the offensive component of the immune system by synthesizing enzymes that seek out and kill microorganisms that penetrate the body’s defenses.
Vitamin B Group
The vitamin B group are generally thought of as contributing to energy production in the body, but folate, B12, B5 and B6 contribute significantly to immune system functions. Vitamin B6, also known as pyridoxine, has demonstrated the ability to increase white blood cell count in the body; these cells are the primary “killer cells” of the immune system. A 2002 study published in “The Journal of Nutrition” found that women who increased their vitamin B6 intake to 2.1 milligrams daily, also increased their white blood cell count by 35 percent.
Vitamin C has been associated with the prevention of colds for many years, due in part, to the research and claims of Dr. Linus Pauling. To date, there are many conflicting studies, but the consensus is that vitamin C does not appear to have a preventative effect on colds based on the dosages given in the studies and their definition of colds. Vitamin C does, however, affect several components of the human immune system. Vitamin C stimulates the production and function of various white blood cells, which attack and kill foreign bacteria and viruses, and are considered the offensive component of the immune system. Vitamin C also helps in the production of interferon, a protein that destroys viruses, and glutathione, an antioxidant which enhances immune system function.
Vitamin D, synthesized from sun exposure, is also essential for a healthy immune system. Researchers at the University of Copenhagen discovered that vitamin D is crucial to activating the “killer T-cells” of the immune system such that they are able to detect and kill foreign pathogens, preventing serious infections. The researchers found that the T-cells rely on vitamin D in order to be activated from a dormant state.
Vitamin E enhances immune system function by producing interleukin-2, an immune protein that kills bacteria, viruses and even cancer cells. In addtion, a 2000 study published in “The Journal of Nutrition” found that vitamin E is an efficient antioxidant and a modulator of the immune system as it improved cell-mediated immunity and oxidative stress in Asian men and women.
- The American Society of Nutritional Sciences - "The Journal of Nutrition"; Improved Vitamin B-6 Status Is Positively Related to Lymphocyte Proliferation in Young Women Consuming a Controlled Diet; Ho-Kyung Kwak et al; 2002
- Oregon State University - Linus Pauling Institute: Vitamin C
- The American Society of Nutritional Sciences - "The Journal of Nutrition"; Vitamin E Supplementation Improves Cell-Mediated Immunity and Oxidative Stress of Asian Men and Women; Fan Wan et al; 2000