The human immune system is dependent on a variety of factors to function properly. Stress, lack of sleep, chronic infections, toxins and malnourishment all reduce immune system function. Conversely, a healthy diet rich in certain vitamins can boost or enhance immunity. Vitamin E, collectively, displays strong antioxidant properties and is able to stimulate cells of the immune system.
Types of Vitamin E
Vitamin E represents a collection of eight fat-soluble substances that are divided into four tocopherol types and four tocotrienol types. Fat-soluble refers to the need of dietary fats for absorption within the intestines and the ability to be stored in the body. Tocopherols are the best studied type and are further divided into alpha, beta, gamma and delta subtypes. Many vitamin E supplements contain only the synthetic form of alpha-tocopherol, although some supplements contain a mix of tocopherols and tocotrienols, which is how vitamin E exists in natural foods. All forms of vitamin E are antioxidants and enhance the immune system to a greater or lesser degree.
Antioxidant Activity
Alpha-tocopherol is the most studied type of vitamin E and considered the most bio-available to the body, according to "Biochemistry of Human Nutrition." Alpha-tocopherol is a powerful antioxidant and is able to eliminate damaging free-radicals linked to blood vessel and tissue damage, degeneration and cancer. Reducing free-radical damage prevents the immune system from being taxed and allows it to use more energy for fighting pathogenic micro-organisms, such as viruses, bacteria and fungi. Tocotrienols are rarely studied, although some research indicates that they are the most potent antioxidants of the vitamin E family, as cited in "Biochemical, Physiological and Molecular Aspects of Human Nutrition."
Immune System Enhancing
According to the National Institutes of Health, alpha-tocopherol also displays anti-inflammatory effects, platelet aggregation inhibition and immune system enhancement. Further, a Chinese study published in 2000 in "The Journal of Nutrition" found that vitamin E supplementation, as alpha-tocopherol, improved cell-mediated immunity and oxidative stress in men and women. Various types of vitamin E enhance immune system function by promoting the synthesis of interleukin-2, a protein that kills bacteria, viruses and even cancer cells.
Recommended Amounts
Vitamin E is not synthesized by the body and must be obtained from dietary or supplemental forms. All types are stored in the body but for a relatively short time, so vitamin E must be consumed on a fairly regular basis. Recommended dietary allowance for vitamin E officially ranges from about 22 to 28 IU daily for adults, but a growing body of research indicates that at least 400 IU per day is more appropriate and up to 1,600 IU is safe, according to "Nutrition and Public Health." Symptoms of deficiency include peripheral neuropathy, muscle weakness, loss of balance, retinopathy and impairment of the immune response.
References
- "Biochemistry of Human Nutrition"; George Gropper; 2000
- "Biochemical, Physiological and Molecular Aspects of Human Nutrition"; Martha Stipanuk; 2006
- National Institutes of Health Office of Dietary Supplements: Vitamin E Fact Sheet
- "The Journal of Nutrition"; Vitamin E Supplementation Improves Cell-Mediated Immunity and Oxidative Stress of Asian Men and Women; F. Wan et al.; December, 2000
- "Nutrition and Public Health"; Sari Edelstein; 2006
