Orange juice and the Immune System Cycle

"In order to prevent disease, it is important to understand the "immune system cycle" and how it works," says Dr. Mehmet Oz, professor of cardiac surgery at Columbia University and co-author of the New York Times bestseller "YOU: The Owner's Manual" (HarperCollins, 2005). 

"The secret to a healthy immune system during cold and flu season can be found through simple lifestyle additions and inside the refrigerator," says Lisa A. Hark PhD. R.D., the Director of the Nutrition Education and Prevention Program at the University of Pennsylvania School of Medicine "In addition to getting a flu shot, people need to get enough sleep, exercise regularly, disinfect often and most importantly, consume a nutritious diet."

Nutrient-rich foods can help support a healthy immune system and unhealthy foods could weaken it by causing inflammation or resulting in a shortfall of nutrients that the immune system needs on an on-going basis to stay healthy.  That's why it is important to choose healthy foods: doing so may yield short-term benefits, including helping the body fight colds and flu, and long-term benefits, potentially helping in the fight against diseases like cancer, heart disease and Alzheimer's.

A healthy lifestyle, starting with diet, is one of the best ways to help the body fight colds and certain diseases.  These eight steps will help support the immune system to ensure good health throughout cold and flu season and a lifetime of better health.

1. Choose nutrient-rich foods: Drinking one glass of 100 percent orange juice , as part of a well-balanced diet, will provide your body with several essential nutrients including folate, flavonoids, vitamins C and B6, carotenoids, potassium and magnesium.
• Folate: Folate is needed to make new cells. Since the immune system needs a constant supply of new cells, folate is essential for a healthy immune system.   Folate can help lower homocysteine levels in the blood.  Homocysteine may contribute to inflammation and has been shown to be related to coronary heart disease and cognitive impairment associated with Alzheimer's disease, when high levels exist (1).  Also, lower intake of folate as an adult has been associated with a higher risk for certain types of cancer (1).
• Flavonoids: Flavonoids are substances that occur in certain plant foods and may have antioxidant, anti-inflammatory, or anti-cancer activities (2). Flavonoids may help in the fight against cancer, heart disease and other serious health problems.
• Vitamin C: One of the most powerful antioxidants, vitamin C is a key nutrient to help the body maintain a healthy immune system and has been associated with modestly reducing the severity or duration of a cold when taken before the onset of illness (3).  Vitamin C also may help neutralize free radicals that can cause cell and tissue damage that could lead to diseases, including cancer and heart disease.  A prominent cancer researcher, Dr. Gladys Block, Ph.D., reports that people with low vitamin C intake (less than 50 mg/day) appeared to have approximately twice the cancer risk, compared to people with higher (greater than 100 mg/day) vitamin C intake (4).
• Vitamin B6: The immune system needs vitamin B6 to function effectively.  It helps maintain the health of lymphoid organs that make white blood cells, which fight infections (1).
• Carotenoids: Carotenoids are precursors to vitamin A, which is important for making new cells and is therefore essential in the maintenance of immune function.  Carotenoids also may have anti-inflammatory activities (5).
• Potassium and Magnesium: These nutrients play an important role in our cardiovascular health by dilating the arteries.  Higher potassium and magnesium intake has been associated with lower blood pressure (6, 7). Any diet containing foods that are a good sources of potassium and low in sodium, such as 100 percent orange juice, may reduce the risk of high blood pressure and stroke, especially as part of a lower-sodium diet, which may help reduce the risk of stroke.
  


2. Get a shot: Visit your doctor or local pharmacy to receive a flu shot before cold and flu season begins.  


3. Get active: It is important to get some fresh air because the body is more vulnerable to cold and flu viruses if constantly indoors. Also, studies show that people who frequently exercise have less severe symptoms of the cold and flu and recover more quickly than those who do not exercise. Aerobic exercise such as bicycling, running, rollerblading and swimming increases the body’s natural ability to kill virus-causing cells, so get moving and help strengthen your body’s immunity.


4. Stay clean: Germs are everywhere, and once we come in contact, it only takes a moment for it to spread to the rest of the body.   Offices and schools are breeding ground for infectious germs, so disinfect as often as possible.  


5. Stay active: A variety of physical activities such as daily walks and weight lifting will help keep the body healthy.


6. Sleep well: Quality of sleep can affect what happens to the body once it comes into contact with the flu virus. Although the recommended daily amount is eight hours, most Americans are only getting seven.  


7. Manage stress: Reduce stress by getting out of the situation, resting and relaxing. Stress can increase infections and aging of the body.


8. Detect disease early: When disease is detected in its beginning stages through check-ups and exams, the body stands a greater chance of survival.  

References:

^1. Institute of Medicine, National Academy of Sciences (1998). Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington DC, Institute of Medicine, National Academy of Sciences.

^2. Manthey, J.A., K. Grohmann, N. Guthrie. (2001) "Biological properties of citrus flavonoids pertaining to cancer and inflammation." Curr Med Chem 8(2):135-53.

^3. Douglas, R., H. Hemila, R. D'Souza, E.B. Chalker, B. Treacy (2004). "Vitamin C for preventing and treating the common cold." The Cochrane Database of Systematic Reviews Issue 4, No. CD000980.

^4. Gladys Block reference (already on Web site)

^5. Institute of Medicine, National Academy of Sciences (2000). Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington DC, Institute of Medicine, National Academy of Sciences.

^6. Whelton, P.K., J. He, J.A. Cutler, F.L. Brancati, L.J. Appel, D. Follmann, M.J. Klag. (1997). "Effects of oral potassium on blood pressure. Meta-analysis of randomized controlled clinical trials." JAMA 277(20):1624-32.

^7. Jee, S.H., E.R. Miller III, E. Guallar, V.K. Singh, L.J. Appel, M.J. Klag. (2002) "The effect of magnesium supplementation on blood pressure: a meta-analysis of randomized clinical trials." Am J Hypertens 15(8):691-6.