forgot password

encyclopedia of health Get your personal health analysis
Welcome to the Truestar Health Encyclopedia the most comprehensive information database available on health, wellness, food, nutrition, vitamins and supplements. Use of our encyclopedia will enable you to make well-informed, responsible decisions for the promotion of your own health and wellness.
Enter search items    

Immune Function

Illustration

The immune system is a complex network of tissues, organs, cells, and chemicals that protects the body from infection and illness. According to research or other evidence, the following self-care steps may help boost your built-in bodyguard:

What you need to know

  • Aim for total nutrition with a multivitamin
  • Get extra vitamins and minerals every day to help prevent deficiencies that make you a target for infections
  • Use exercise wisely
  • Take advantage of the benefits of moderate exercise on immune function—but be careful about prolonged or intense exercise, which can temporarily increase your risk of infection
  • Get the good bacteria
  • Stimulate the intestine’s immune system and slow growth of infectious organisms in the intestine by regularly eating yogurt and other foods containing live cultures, or take a supplement containing 10 billion colony-forming units a day of acidophilus or bifidobacteria
  • Avoid alcohol binges
  • Keep your alcohol intake low or moderate to avoid damaging effects to your immune system
  • Update your vaccinations
  • Consult your medical provider to see if you need vaccines for influenza, pneumonia, hepatitis, tetanus, and other infections

These recommendations are not comprehensive and are not intended to replace the advice of your doctor or pharmacist. Continue reading the full immune function article for more in-depth, fully-referenced information on medicines, vitamins, herbs, and dietary and lifestyle changes that may be helpful.

About immune function

The immune system is an intricate network of specialized tissues, organs, cells, and chemicals. The lymph nodes, spleen, bone marrow, thymus gland, and tonsils all play a role, as do lymphocytes (specialized white blood cells), antibodies, and interferon.

Two types of immunity protect the body: innate and adaptive. Innate immunity is present at birth and provides the first barrier against microorganisms. The skin, mucus secretions, and the acidity of the stomach are examples of innate immunity that act as barriers to keep unwanted germs away from more vulnerable tissues.

Adaptive immunity is the second barrier to infection. It is acquired later in life, such as after an immunization or successfully fighting off an infection. The adaptive immune system retains a memory of all the invaders it has faced. This is why people usually get the measles only once, although they may be repeatedly exposed to the disease. Unfortunately some bugs—such as the viruses that cause the common cold—“disguise” themselves and must be fought off time and again by the immune system.

Product ratings for immune function

Science Ratings Nutritional Supplements Herbs
3Stars

Multiple vitamin-mineral (for elderly people)

Vitamin E (for elderly people)

Andrographis

2Stars

Acidophilus

Beta-carotene

Fish oil (omega-3 fatty acids for critically ill and post surgery patients only)

Glutamine (for prevention of post-exercise infection in performance athletes)

Selenium (for elderly people)

Thymus extracts

Vitamin A

Vitamin C

Zinc (for elderly people)

Ashwagandha

Asian ginseng

Echinacea

Eleuthero

1Star

Beta-glucan

Cordyceps

DHEA

Lycopene

Vitamin B12

Whey protein

Zinc (for non-elderly people)

Astragalus

Cat’s claw

Fo-ti

Green tea

Ligustrum

Maitake

Noni

3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

What are the symptoms?

Symptoms of decreased immune function include frequent colds and flus, recurring parasitic infections, initially mild infections that become serious, opportunistic infections (infections by organisms that are usually well controlled by a healthy immune system, such as toxoplasmosis, cryptococcosis, and cytomegalovirus), and cancer.

Medical options

Prescription drug therapy includes preventative antibiotics, as well as immune-boosting medicines such as interferon (Roferon-A®, Intron A, Infergen®) and interleukin (Proleukin®).

Treatment for decreased immune functioning also includes vaccination for the flu, pneumococcus (a cause of pneumonia), hepatitis, tetanus, and other infections combined with precautions to reduce exposure to infectious agents.

Dietary changes that may be helpful

All forms of sugar (including honey) interfere with the ability of white blood cells to destroy bacteria.1 2 Animal studies suggest diets high in sucrose (table sugar) impair some aspects of immune function.3 4 The importance of these effects in the prevention of infections in humans remains unclear.

Alcohol intake, including single episodes of moderate consumption, interferes with a wide variety of immune defenses.5 6 Alcohol’s immune-suppressive effect may be one mechanism for the association between alcohol intake and certain cancers7 and infections.8 9 However, moderate alcohol consumption (up to three to four drinks per day) has been associated in preliminary studies with either no risk10 or a decreased risk for upper respiratory infections in young nonsmokers.11

The effect of fats on the immune system is complex and only partially understood. Excessive intake of total dietary fat impairs immune response, but some types of fat may be neutral or even beneficial.12 For example, monounsaturated fats, as found in olive oil, appear to have no detrimental effect on the immune system in humans at reasonable dietary levels.13

Research on the effect of the omega-3 fatty acids that are abundant in some fish, fish oils, and flaxseed oil is conflicting. Liquid diets containing omega-3 fatty acids used in hospitals for critically ill people have been shown to improve immune function and reduce infections.14 15 However, in one controlled study in healthy people, a low-fat diet improved or maintained immune function, but when fish was added to increase omega-3 fatty acid intake, immune function was significantly inhibited.16

Supplementation with DHA (an omega-3 fatty acid found in fish oil) in healthy young men has been shown to decrease the activity of immune cells, such as natural killer (NK) cells, and to inhibit certain measures of inflammation in the test tube.17 The anti-inflammatory effects of DHA may be useful in the management of autoimmune disorders; however, such benefits need to be balanced with the potential for increased risk of infections. Other studies suggest that increased oxidative damage might be the reason for the negative effects on the immune system sometimes caused by fish oil, and that increased intake of antioxidants, such as vitamin E, could correct the problem.18

As with omega-3 fatty acids, omega-6 fatty acids (as found in vegetable oils) have also produced conflicting effects on the immune system. Enriching a low-fat diet with omega-6 fatty acids did not impair immunity.19 However, diets high in omega-6 fatty acids have suppressed immunity in other reports.20 21

In summary, low-fat diets with moderate levels of monounsaturated fat from olive oil appear least likely to compromise immune function and may provide small benefits. Conclusions about the desirability of diets high in either omega-3 or omega-6 fatty acid supplementation await further research.

Many studies, in both animals and humans, have demonstrated immune-stimulating effects from yogurt which contains live cultures, such as Lactobacillus acidophilus and other probiotics (friendly bacteria). The effects of probiotics observed in humans include increasing the activity of several types of white blood cells. In preliminary human studies, consumption of live culture-containing yogurt has been associated with a reduced incidence of several immune-related diseases, including cancer, infections of the stomach and intestines, and some allergic reactions.22

Lifestyle changes that may be helpful

Both excessive thinness and severe obesity are associated with impaired immune responses.23 Obesity increases the risk of infection, at least in hospitalized patients, according to preliminary research.24 However, these effects may not occur with mild to moderate obesity in otherwise healthy people, and attempts to lose weight through dietary restriction may actually be harmful to the immune system.25 The detrimental effects of both excess weight and weight-loss diets appear to be offset when people regularly perform aerobic exercise.26 27

The effects of exercise on immune function depend on many factors, including frequency and intensity of exercise.28 Regular moderate physical activity has positive effects, at least on some measures of immunity, and has been shown to reduce risk of upper respiratory infection. However, very intense and prolonged exercise, such as running a marathon or overtraining, can, in the short term, actually increase the risk of developing infections.29 The positive effects of moderate exercise on immunity may also partly explain the apparent reduced susceptibility to cancer of physically active people.30

Vitamins that may be helpful

Most,31 32 but not all,33 double-blind studies have shown that elderly people have better immune function and reduced infection rates when taking a multiple vitamin-mineral formula. In one double-blind trial, supplements of 100 mcg per day of selenium and 20 mg per day of zinc, with or without additional vitamin C, vitamin E, and beta-carotene, reduced infections in elderly people, though vitamins without minerals had no effect.34 Burn victims have also experienced fewer infections after receiving trace mineral supplements in double-blind research.35 These studies suggest that trace minerals may be the most important micronutrients for enhancing immunity and preventing infections in the elderly.

Vitamin E enhances some measures of immune-cell activity in the elderly.36 This effect is more pronounced with 200 IU per day compared to either lower (60 IU per day) or higher (800 IU per day) amounts, according to double-blind research.37 Intakes under 200 IU per day have not boosted immune function in some reports.38

Beta-carotene and other carotenoids have increased immune cell numbers and activity in animal and human research, an effect that appears to be separate from their role as precursors to vitamin A.39 40 Placebo-controlled research has shown positive benefits of beta-carotene supplements in increasing numbers of some white blood cells and enhancing cancer-fighting immune functions in healthy people at 25,000–100,000 IU per day.41 42

In double-blind trials in the elderly, supplementation with 40,000–150,000 IU per day of beta-carotene has increased natural killer (NK) cell activity,43 but not several other measures of immunity.44

Controlled research has found that 50,000 IU per day of beta-carotene boosted immunity in people with colon cancer but in not those with precancerous conditions in the colon.45 Beta-carotene has also prevented immune suppression from ultraviolet light exposure.46 Effects on immunodefiency in HIV-positive people have been inconsistent using beta-carotene.47 48

Vitamin C stimulates the immune system by both elevating interferon levels49 and enhancing the activity of certain immune cells.50 51 Two studies came to opposite conclusions about the ability of vitamin C to improve immune function in the elderly,52 53 and two other studies did not agree on whether vitamin C could protect people from hepatitis.54 55 However, a review of 20 double-blind studies concluded that while several grams of vitamin C per day has only a small effect in preventingcolds, when taken at the onset of a cold, it does significantly reduce the duration of a cold.56 In controlled reports studying people doing heavy exercise, cold frequency was reduced an average of 50% with vitamin C supplements ranging from 600 to 1,000 mg per day.57 Thus, the overall effect of vitamin C on immune function is unclear, and its usefulness may vary according to the situation.

Vitamin A plays an important role in immune system function and helps mucous membranes, including those in the lungs, resist invasion by microorganisms.58 However, most research shows that while vitamin A supplementation helps people prevent or treat infections in developing countries where deficiencies are common,59 little to no positive effect, and even slight adverse effects, have resulted from giving vitamin A supplements to people in countries where most people consume adequate amounts of vitamin A.60 61 62 63 64 65 66 Moreover, vitamin A supplementation during infections appears beneficial only in certain diseases. An analysis of trials revealed that vitamin A reduces mortality from measles and diarrhea, but not from pneumonia, in children living in developing countries.67 A double-blind trial of vitamin A supplementation in Tanzanian children with pneumonia confirmed its lack of effectiveness for this condition.68 In general, parents in the developed world should not give vitamin A supplements to children unless there is a reason to believe vitamin A deficiency is likely, such as the presence of a condition causing malabsorption (e.g., celiac disease). However, the American Academy of Pediatrics recommends that all children with measles be given short-term supplementation with high-dose vitamin A in cases of hospitalization, malnutrition, and other special circumstances determined by a doctor.69

A combination of antioxidants vitamin A, vitamin C, and vitamin E significantly improved immune cell number and activity compared with placebo in a group of hospitalized elderly people.70 Daily intake of a 1,000 mg vitamin C plus 200 IU vitamin E for four months improved several measures of immune function in a preliminary study.71 To what extent immune-boosting combinations of antioxidants actually reduce the risk of infection remains unknown.

The amino acid glutamine is important for immune system function. Liquid diets high in glutamine have been reported in controlled studies to be more helpful to critically ill people than other diets.72 73 Endurance athletes are susceptible to upper respiratory tract infections after heavy exercise, which depletes glutamine levels in blood.74 Although the effects of glutamine supplementation on immune function after exercise have been inconsistent,75 76 a double-blind study giving athletes glutamine (2.5 grams after exercise and again two hours later) reported significantly fewer infections with glutamine.77

Supplements of probiotics (friendly bacteria) such as Lactobacillus acidophilus, or the growth factors that encourage their development in the gastrointestinal tract may help protect the body from harmful organisms in the intestine that cause local or systemic infection according to published research,78 79 including controlled80 trials. The effective amount of probiotics depends on the strain used, as well as the concentration of viable organisms. Infectious diarrhea in children has been successfully reduced with supplements of friendly bacteria in several trials, some of which were double-blind.81 82

The thymus gland is responsible for many immune system functions. Preliminary studies suggest that a thymus extract known as Thymomodulin® may improve immune function, and double-blind trials in children and adults with a history of recurrent respiratory-tract infections have found reduced numbers of recurrent infections with Thymomodulin supplementation.83 84 85 86 87 Thymomodulin has also been shown in a double-blind study to improve immune function in cases of exercise-induced immune suppression, and in preliminary studies to improve immune function in people with diabetes and in elderly people.88 89 90 91

Zinc supplements have been reported to increase immune function.92 93 This effect may be especially important in the elderly according to double-blind studies.94 95 Some doctors recommend zinc supplements for people with recurrent infections, suggesting 25 mg per day for adults and lower amounts for children (depending on body weight). However, too much zinc (300 mg per day) has been reported to impair immune function.96

While zinc lozenges have been shown to be effective for reducing the symptoms and duration of the common cold in some controlled studies, it is not clear whether this effect is due to an enhancement of immune function or to the direct effect of zinc on the viruses themselves.97

Large amounts of the carotenoid lycopene have been shown to increase the activity of NK cells in the elderly. In a controlled trial, 15 mg of lycopene significantly increased NK cell concentration, but no other immune functions.98

A deficiency of vitamin B12 has been associated with decreased immune function. In a controlled trial, people with vitamin B12 deficiency anemia were also found to have markedly decreased levels of white blood cells associated with immune function.99 Restoration of vitamin B12 stores by means of injections improved levels of these immune cells, suggesting an important role for vitamin B12 in immune function.

Beta-glucan is a fiber-type polysaccharide (complex sugar) derived from the cell wall of baker’s yeast, oat and barley fiber, and many medicinal mushrooms, such as maitake. Numerous experimental studies in test tubes and animals have shown beta-glucan to activate white blood cells.100 101 102 103 104 In fact, there have been hundreds of research papers on beta-glucan since the 1960s.105 The research indicates that beta-1,3-glucan, in particular, is very effective at activating white blood cells known as macrophages and neutrophils. A beta-glucan–activated macrophage or neutrophil can recognize and kill tumor cells, remove cellular debris resulting from oxidative damage, speed up recovery of damaged tissue, and further activate other components of the immune system.106 107 Although the research in test tube and animal studies is promising, many questions remain about the effectiveness of beta-glucan as an oral supplement to enhance immune function in humans. Controlled trials are necessary to determine whether humans can benefit from beta-glucan, and in what amounts oral beta-glucan must be taken from meaningful effects.

The hormone DHEA effects immunity. In a controlled trial, a group of elderly men with low DHEA levels who were given a high level of DHEA (50 mg per day) for 20 weeks, experienced a significant activation of immune function.108 Postmenopausal women have also shown increased immune functioning in just three weeks when given DHEA in double-blind research.109

The effects of eating fish and other dietary sources of omega-3 fatty acids is discussed above in the nutritional section. In terms of fish oil supplements, except for effects in hospitalized patients, most studies have reported that additional omega-3 intake decreases immune function.110 111 112 113 Antioxidants may correct this problem, according to preliminary research.114

Liquid diets containing supplemental arginine, omega-3 fatty acids, and nucleotides such as ribonucleic acid (RNA) have been more effective than other liquid diets in both maintaining immune function and reducing infections in critically ill and post-surgical hospital patients in most,115 116 117 118 119 but not all,120 121 double-blind trials. Typical daily intakes in these trials are 3.3 grams of omega 3 fatty acids, 12.5 grams of arginine, and 1.2 grams of RNA. No research has studied the effects of these supplements in people with less severe health problems.

A double-blind trial showed that 45 grams per day of whey protein increased blood glutathione levels in a group of HIV-infected people.122 Test tube123 124 and animal125 studies suggest that whey protein may improve some aspects of immune function.

Are there any side effects or interactions?
Refer to the individual supplement for information about any side effects or interactions.

Herbs that may be helpful

In general, human studies have found that echinacea taken orally stimulates the function of a variety of immune cells, particularly natural killer cells.126 The balance of evidence currently available from studies suggests that echinacea speeds recovery from the common cold, via immune stimulation (as opposed to killing the cold virus directly).127 Evidence on preventing the common cold with echinacea is largely negative, suggesting its immune-stimulating activity may be mild in generally healthy people. Other studies on oral echinacea have not found that it stimulates activity of the white blood cells known as neutrophils.128 Many doctors recommend 3–5 ml of tincture three times per day to improve immune function. Echinacea in capsule form is also commonly available.

Andrographis has been shown in a double-blind trial to successfully reduce the severity of the common cold.129 A preliminary study also suggests it may prevent the onset of a cold in healthy people.130 These actions are thought to be due to the immune system enhancing actions of the active constituents known as andrographolides.131

Asian ginseng has a long history of use in traditional herbal medicine for preventing and treating conditions related to the immune system. A double-blind study of healthy people found that taking 100 mg of a standardized extract of Asian ginseng twice per day improved immune function.132

Eleuthero (Siberian ginseng) has also historically been used to support the immune system. Preliminary Russian research has supported this traditional use.133 A double-blind study has shown that healthy people who take 10 ml of eleuthero tincture three times per day had an increase in certain T lymphocytes important to normal immune function. These effects have not been studied in people with lowered immune function. The amount of eleuthero used in this trial is exceptionally high, though no side effects were seen.

Ashwagandha is considered a general stimulant of the immune system,134 and has been called a tonic or adaptogen135 —an herb with multiple, nonspecific actions that counteract the effects of stress and generally promote wellness. More research is needed to better evaluate these claims.

Complex polysaccharides present in astragalus and in maitake and coriolus mushrooms appear to act as “immunomodulators” and, as such, are being researched for their potential role in AIDS and cancer. Presently, the only human studies on astragalus indicate that it can prevent white blood cell numbers from falling in people given chemotherapy and radiotherapy and can elevate antibody levels in healthy people.136 Maitake has only been studied in animals as a way to increase immune function.137 The primary immuno-activating polysaccharide found in these mushrooms, beta-D-glucan, is well absorbed when taken orally138 and is currently under investigation as a supportive tool for HIV infection. Results from future research will improve the understanding of the possible benefits of these mushrooms and their constituents.

Substances found in cat’s claw, called oxyindole alkaloids have been shown to stimulate the immune system.139 However, little is known about whether this effect is sufficient to prevent or treat disease.

Cordyceps has immune strengthening actions in human and animal studies.140 141 Further research is needed but it may be helpful in a wide range of conditions in which the immune system is weakened. The usual amount taken is 3 to 4.5 grams twice daily as capsules or simmered for 10 to 15 minutes in water for tea.

Green tea has stimulated production of immune cells and has shown anti-bacterial properties in animal studies.142 143 144 More research is needed to evaluate the effectiveness of green tea in protecting against infection and other immune system-related diseases.

Preliminary research suggests that fo-ti plays a role in a strong immune system and has antibacterial action.145 More research is needed to further understand the potential importance of these effects.

The main active compound in ligustrum is ligustrin (oleanolic acid). Studies, mostly conducted in China, suggest that ligustrum stimulates the immune system.146 Ligustrum is often combined with astragalus in traditional Chinese medicine. Although used for long-term support of the immune system in people with depressed immune function or cancer, more research is needed to demonstrate the optimal length of time to use ligustrum.

Animal and test tube studies show noni to have some immune-enhancing activity. Specifically, the polysaccharide component has been shown to increase the release of immune-enhancing compounds that activate white blood cells to destroy tumor cells.147 The usual recommendation is 4 ounces of noni juice 30 minutes before breakfast (effectiveness is thought to be best on an empty stomach). Human studies are needed to confirm the usefulness of noni.

Are there any side effects or interactions?
Refer to the individual herb for information about any side effects or interactions.

Holistic approaches that may be helpful

The immune system is suppressed during times of stress. Chronic mental and emotional stress can reduce immune function, but whether this effect is sufficient to increase the risk of infection or cancer is less clear.148 149 Nevertheless, immune function has been increased by stress-reducing techniques such as relaxation exercises, biofeedback, and other approaches,150 151 although not all studies have shown a significant effect.152

References:

1. Sanchez A, Reeser JL, Lau HS, et al. Role of sugars in human neutrophilic phagocytosis. Am J Clin Nutr 1973;26:1180–4.

2. Ringsdorf WM, Cheraskin E, Ramsay RR. Sucrose, neutrophilic phagocytosis and resistance to disease. Dent Survey 1976;52(12):46.

3. Nutter RL, Gridley DS, Kettering JD, et al. Modification of a transplantable colon tumor and immune responses in mice fed different sources of protein, fat and carbohydrate. Cancer Lett 1983;18(1):49–62.

4. Kos WL, Kos KA, Kaplan AM. Impaired function of immune reactivity to Listeria monocytogenes in diet-fed mice. Infect Immun 1984;43:1094–6.

5. Ahmed FE. Toxicological effects of ethanol on human health. Crit Rev Tox 1995;25(4):347–67.

6. Szabo G. Monocytes, alcohol use, and altered immunity. Alcohol Clin Exp Res 1998;22:216–9S.

7. Seitz HK, Poschl G, Simanowski UA. Alcohol and cancer. Recent Dev Alcohol 1998;14:67–95 [review].

8. MacGregor RR, Louria DB. Alcohol and infection. Curr Clin Top Infect Dis 1997;17:291–315 [review].

9. Balla AK, Lischner HW, Pomerantz RJ, et al. Human studies on alcohol and susceptibility to HIV infection. Alcohol 1994;11:99–103 [review].

10. Engs RC, Aldo-Benson M. The association of alcohol consumption with self-reported illness in university students. Psychol Rep 1995;76:727–36.

11. Cohen S, Tyrrell DA, Russell MA, et al. Smoking, alcohol consumption, and susceptibility to the common cold. Am J Public Health 1993;83:1277–83.

12. Kelley DS, Daudu PA. Fat intake and immune response. Prog Food Nutr Sci 1993;17:41–63 [review].

13. Yaqoob P. Monounsaturated fats and immune function. Proc Nutr Soc 1998;57:511–20 [review].

14. Tashiro T, Yamamori H, Takagi K, et al. n-3 versus n-6 polyunsaturated fatty acids in critical illness. Nutrition 1998;14:551–3.

15. Gerster H. The use of n-3 PUFAs (fish oil) in enteral nutrition. Int J Vitam Nutr Res 1995;65:3–20 [review].

16. Meydani SN, Lichtenstein AH, Cornwall S, et al. Immunologic effects of national cholesterol education panel step-2 diets with and without fish-derived n-3 fatty acid enrichment. J Clin Invest 1993;92:105–13.

17. Kelley DS, Taylor PC, Nelson GJ, et al. Docosahexaenoic acid ingestion inhibits natural killer cell activity and production of inflammatory mediators in young healthy men. Lipids 1999;34:317–24.

18. Wu D, Meydani SN. n-3 polyunsaturated fatty acids and immune function. Proc Nutr Soc 1998;57:503–9 [review].

19. Kelley DS, Dougherty RM, Branch LB, et al. Concentration of dietary N-6 polyunsaturated fatty acids and the human immune status. Clin Immunol Immunopathol 1992;62:240–4.

20. Rasmussen LB, Kiens B, Pedersen BK, et al. Effect of diet and plasma fatty acid composition on immune status in elderly men. Am J Clin Nutr 1994;59:572–7.

21. Wan JM, Teo TC, Babayan VK, et al. Invited comment: lipids and the development of immune dysfunction and infection. JPEN J Parenter Enteral Nutr 1988;12:43S–52S.

22. Meydani SN, Ha WK. Immunologic effects of yogurt. Am J Clin Nutr 2000;71:861–72 [review].

23. Chandra RK. Nutrition and the immune system: an introduction. Am J Clin Nutr 1997;66:460–3S [review].

24. Stallone DD. The influence of obesity and its treatment on the immune system. Nutr Rev 1994;52:37–50.

25. Nieman DC, Nehlsen-Cannarella SI, Henson DA, et al. Immune response to obesity and moderate weight loss. Int J Obes Relat Metab Disord 1996;20:353–60.

26. Nieman DC, Henson DA, Nehlsen-Cannarella SL. Influence of obesity on immune function. J Am Diet Assoc 1999;99:294–9.

27. Scanga CB, Verde TJ, Paolone AM, et al. Effects of weight loss and exercise training on natural killer cell activity in obese women. Med Sci Sports Exerc 1998;30:1666–71.

28. Nieman DC. Exercise immunology: practical applications. Int J Sports Med 1997;18:S91–100 [review].

29. Nieman DC. Exercise and resistance to infection. Can J Physiol Pharmacol 1998;76:573–80 [review].

30. Shephard RJ, Shek PN. Associations between physical activity and susceptibility to cancer: possible mechanisms. Sports Med 1998;26:293–315 [review].

31. Pike J, Chandra RK. Effect of vitamin and trace element supplementation on immune indices in healthy elderly. Int J Vitam Nutr Res 1995;65:117–21.

32. Chandra RK. Effect of vitamin and trace-element supplementation on immune responses and infection in elderly subjects. Lancet 1992;340:1124–7.

33. Chavance M, Herbeth B, Lemoine A, et al. Does multivitamin supplementation prevent infections in healthy elderly subjects? A controlled trial. Int J Vitam Nutr Res 1993;63:11–6.

34. Girodon F, Lombard M, Galan P, et al. Effect of micronutrient supplementation on infection in institutionalized elderly subjects: a controlled trial. Ann Nutr Metab 1997;41:98–107.

35. Berger MM, Spertini F, Shenkin A, et al. Trace element supplementation modulates pulmonary infection rates after major burns: a double-blind, placebo-controlled trial. Am J Clin Nutr 1998;68:365–71.

36. Meydani SN, Barklund MP, Liu S, et al. Vitamin E supplementation enhances cell-mediated immunity in healthy elderly subjects. Am J Clin Nutr 1990;52:557–63.

37. Meydani SN, Meydani M, Blumberg JB, et al. Vitamin E supplementation and in vivo immune response in healthy elderly subjects: a randomized controlled trial. JAMA 1997;277:1380–6.

38. De Waart FG, Portengen L, Doekes G, et al. Effect of 3 months vitamin E supplementation on indices of the cellular and humoral immune response in elderly subjects. Br J Nutr 1997;78:761–74.

39. Chew BP. Role of carotenoids in the immune response. J Dairy Sci 1993;76:2804–11.

40. Bendich A. Beta-carotene and the immune response. Proc Nutr Soc 1991;50:263–74.

41. Hughes DA, Wright AJ, Finglas PM, et al. The effect of beta-carotene supplementation on the immune function of blood monocytes from healthy male nonsmokers. J Lab Clin Med 1997;129:309–17.

42. Murata T, Tamai H, Morinobu T, et al. Effect of long-term administration of beta-carotene on lymphocyte subsets in humans. Am J Clin Nutr 1994;60:597–602.

43. Santos MS, Meydani SN, Leka L, et al. Natural killer cell activity in elderly men is enhanced by beta-carotene supplementation. Am J Clin Nutr 1996;64:772–7.

44. Santos MS, Leka LS, Ribaya-Mercado JD, et al. Short- and long-term beta-carotene supplementation do not influence T cell-mediated immunity in healthy elderly persons. Am J Clin Nutr 1997;66:917–24.

45. Kazi N, Radvany R, Oldham T, et al. Immunomodulatory effect of beta-carotene on T lymphocyte subsets in patients with resected colonic polyps and cancer. Nutr Cancer 1997;28:140–5.

46. Fuller CJ, Faulkner H, Bendich A, et al. Effect of beta-carotene supplementation on photosuppression of delayed-type hypersensitivity in normal young men. Am J Clin Nutr 1992;56:684–90.

47. Coodley GO, Coodley MK, Lusk R, et al. Beta-carotene in HIV infection: an extended evaluation. AIDS 1996;10:967–73.

48. Fryburg DA, Mark RJ, Griffith BP, et al. The effect of supplemental beta-carotene on immunologic indices in patients with AIDS: a pilot study. Yale J Biol Med 1995;68:19–23.

49. Gerber WF, Lefkowitz SS, Hung CY. Effect of ascorbic acid, sodium salicylate, and caffeine on the serum interferon level in response to viral infection. Pharmacology 1975;13:228.

50. Anderson R. The immunostimulatory, anti-inflammatory an anti-allergic properties of ascorbate. Adv Nutr Res 1984;6:19–45 [review].

51. Banic S. Immunostimulation by vitamin C. Int J Vitam Nutr Res Suppl 1982;23:49–52 [review].

52. Delafuente JC, Prendergast JM, Modigh A. Immunologic modulation by vitamin C in the elderly. Int J Immunopharmacol 1986;8:205–11.

53. Kennes B, Dumont I, Brohee D, et al. Effect of vitamin C supplements on cell-mediated immunity in old people. Gerontology 1983;29:305–10.

54. Murata A. Virucidal activity of vitamin C for prevention and treatment of viral diseases. In Proceedings of the First Intersectional Congress of IAMS, vol 3. Science Council Japan, 1975, 432.

55. Knodell RG, Tate MA, Akl BF, et al. Vitamin C prophylaxis for posttransfusion hepatitis: Lack of effect in a controlled trial. Am J Clin Nutr 1981;34(1):20–3.

56. Hemilä H. Vitamin C and the common cold. Br J Nutr 1992;67:3–16.

57. Hemilä H. Vitamin C and common cold incidence: a review of studies with subjects under heavy physical stress. Int J Sports Med 1996;17:379–83.

58. Semba RD. Vitamin A, immunity, and infection. Clin Infect Dis 1994;19:489–99 [review].

59. Glasziou PP, Mackerras DEM. Vitamin A supplementation in infectious diseases: a meta-analysis. BMJ 1993;306:366–70.

60. Stephensen CB, Franchi LM, Hernandez H, et al. Adverse effects of high-dose vitamin A supplements in children hospitalized with pneumonia. Pediatrics 1998;101(5):E3 [abstract].

61. Bresee JS, Fischer M, Dowell SF, et al. Vitamin A therapy for children with respiratory syncytial virus infection: a multicenter trial in the United States. Pediatr Infect Dis J 1996;15:777–82.

62. Quinlan KP, Hayani KC. Vitamin A and respiratory syncytial virus infection. Serum levels and supplementation trial. Arch Pediatr Adolesc Med 1996;150:25–30.

63. Kjolhede CL, Chew FJ, Gadomski AM, et al. Clinical trial of vitamin A as adjuvant treatment for lower respiratory tract infections. J Pediatr 1995;126:807–12.

64. Pinnock CB, Douglas RM, Badcock NR. Vitamin A status in children who are prone to respiratory tract infections. Aust Paediatr J 1986;22:95–9.

65. Murphy S, West KP Jr, Greenough WB 3d, et al. Impact of vitamin A supplementation on the incidence of infection in elderly nursing-home residents: a randomized controlled trial. Age Ageing 1992;21:435–9.

66. Fawzi WW, Mbise R, Spiegelman D, et al. Vitamin A supplements and diarrheal and respiratory tract infections among children in Dar es Salaam, Tanzania. J Pediatr 2000;137:660–7.

67. Ross AC. Vitamin A supplementation as therapy--are the benefits disease specific? Am J Clin Nutr 1998;68:8–9 [review].

68. Fawzi WW, Mbise RL, Fataki MR, et al. Vitamin A supplementation and severity of pneumonia in children admitted to the hospital in Dar es Salaam, Tanzania. Am J Clin Nutr 1998;68:187–92.

69. American Academy of Pediatrics Committee on Infectious Diseases. Vitamin A treatment of measles. Pediatrics 1993,91:1014–5.

70. Penn ND, Purkins L, Kelleher J, et al. The effect of dietary supplementation with vitamins A, C and E on cell-mediated immune function in elderly long-stay patients: a randomized controlled trial. Age Ageing 1991;20:169–74.

71. de la Fuente M, Ferrandez MD, Burgos MS, et al. Immune function in aged women is improved by ingestion of vitamins C and E. Can J Physiol Pharmacol 1998;76:373–80.

72. Jones C, Palmer TE, Griffiths RD. Randomized clinical outcome study of critically ill patients given glutamine-supplemented enteral nutrition. Nutrition 1999;15:108–15.

73. Griffiths RD. Outcome of critically ill patients after supplementation with glutamine. Nutrition 1997;13:752–4 [review].

74. Nieman DC. Exercise and resistance to infection. Can J Physiol Pharmacol 1998;76:573–80 [review].

75. Rohde T, MacLean DA, Pedersen BK. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Med Sci Sports Exerc 1998;30:856–62.

76. Castell LM, Newsholme EA. Glutamine and the effects of exhaustive exercise upon the immune response. Can J Physiol Pharmacol 1998;76:524–32 [review].

77. Castell LM, Poortmans JR, Newsholme EA. Does glutamine have a role in reducing infections in athletes? Eur J Appl Physiol 1996;73:488–90.

78. Fernandes CF, Shahani KM, Amer MA. Therapeutic role of dietary lactobacilli and lactobacillic fermented dairy products. FEMS Micro Rev 1987;46:343–56.

79. Bengmark S. Immunonutrition: role of biosurfactants, fiber, and probiotic bacteria. Nutrition 1998;14:585–94 [review].

80. Phuapradit P, Varavithya W, Vathanophas K, et al. Reduction of rotavirus infection in children receiving bifidobacteria-supplemented formula. J Med Assoc Thai 1999;82:S43–8.

81. Pedone CA, Arnaud CC, Postaire ER, et al. Multicentric study of the effect of milk fermented by Lactobacilus casei on the incidence of diarrhea. Int J Clin Pract 2000;54:568–71.

82. Saavedra J. Probiotics and infectious diarrhea. Am J Gastroenterol 2000;95:S16–8.

83. Fiocchi A, Borella E, Riva E, et al. A double-blind clinical trial for the evaluation of the therapeutic effectiveness of a calf thymus derivative (Thymomodulin) in children with recurrent respiratory infections. Thymus 1986;8:831–9.

84. Galli L, de Martino M, Azzari C, et al. Preventive effect of thymomodulin in recurrent respiratory infections in children. Pediatr Med Chir 1990;12:229–32.

85. Vettori G, Lazzaro A, Mazzanti P, Cazzola P. Prevention of recurrent respiratory infections in adults. Minerva Med 1987;78:1281–9.

86. Longo F, Lepore L, Agosti E, Panizon F. Evaluation of the effectiveness of thymomodulin in children with recurrent respiratory infections. Pediatr Med Chir 1988;10:603–7.

87. Maiorano V, Chianese R, Fumarulo R, et al. Thymomodulin increases the depressed production of superoxide anion by alveolar macrophages in patients with chronic bronchitis. Int J Tissue React 1989;11:21–5.

88. Garagiola U, Buzzetti M, Cardella E. Immunological patterns during regular intensive training in athletes: quantification and evaluation of a preventive pharmacological approach. J Int Med Res 1995;23:85–95.

89. Wysocki J, Wierusz-Wysocka B, Wykretowicz A, Wysocki H. The influence of thymus extracts on the chemotaxis of polymorphonuclear neutrophils (PMN) from patients with insulin-dependent diabetes mellitus (IDD). Thymus 1992;20:63–7.

90. Calsini P, Mocchegiani E, Fabris N. The pharmacodynamics of thymomodulin in elderly humans. Drugs Exp Clin Res 1985;11:671–4.

91. Braga PC, Dal Sasso M, Maci S, et al. Restoration of polymorphonuclear leukocyte function in elderly subjects by thymomodulin. J Chemother 1994;6:354–9.

92. Duchateau J, Delespesse G, Vereecke P. Influence of oral zinc supplementation on the lymphocyte response to mitogens of normal subjects. Am J Clin Nutr 1981;34:88–93.

93. Fraker PJ, Gershwin ME, Good RA, Prasad A. Interrelationships between zinc and immune function. Fed Proc 1986;45:1474–9.

94. Fortes C, Forastiere F, Agabiti N, et al. The effect of zinc and vitamin A supplementation on immune response in an older population. J Am Geriatr Soc 1998;46:19–26.

95. Girodon F, Lombard M, Galan P, et al. Effect of micronutrient supplementation on infection in institutionalized elderly subjects: a controlled trial. Ann Nutr Metab 1997;41:98–107.

96. Chandra RK. Excessive intake of zinc impairs immune responses. JAMA 1984;252:1443–6.

97. Macknin ML. Zinc lozenges for the common cold. Cleveland Clin J Med 1999;66:27–32 [review].

98. Corridan BM, O’Donohue MP, Morrissey PA. Carotenoids and immune response in elderly people. Proc Nutr Soc 1998;57:3A–4A.

99. Tamura J, Kubota K, Murakami H, et al. Immunomodulation by vitamin B12: augmentation of CD8+ T lymphocytes and natural killer (NK) cell activity in vitamin B12-deficient patients by methyl-B12 treatment. Clin Exp Immunol 1999;116:28–32.

100. Czop JK. The role of beta-glucan receptors on blood and tissue leukocytes in phagocytosis and metabolic activation. Pathol Immunopathol Res 1986;5:286–96.

101. Wakshull E, Brunke-Reese D, Lindermuth J, et al. PGG-glucan, a soluble beta-(1,3)-glucan, enhances the oxidative burst response, microbicidal activity, and activates an NF-kappa B-like factor in human PMN: evidence for a glycosphingolipid beta-(1,3)-glucan receptor. Immunopharmacology 1999;41:89–107.

102. Czop JK, Kay J. Isolation and characterization of beta-glucan receptors on human mononuclear phagocytes. J Exp Med 1991;173:1511–20.

103. Czop JK, Puglisi AV, Miorandi DZ, Austen KF. Perturbation of beta-glucan receptors on human neutrophils initiates phagocytosis and leukotriene B4 production. J Immunol 1988;141:3170–6.

104. Estrada A, Yun CH, Van Kessel A, et al. Immunomodulatory activities of oat beta-glucan in vitro and in vivo. Microbiol Immunol 1997;41:991–8.

105. Ooi VE, Liu F. Immunomodulation and anti-cancer activity of polysaccharide-protein complexes. Curr Med Chem 2000;7:715–29 [review].

106. Ross GD, Vetvicka V, Yan J, et al. Therapeutic intervention with complement and beta-glucan in cancer. Immunopharmacology 1999;42:61–74.

107. Di Renzo L, Yefenof E, Klein E. The function of human NK cells is enhanced by beta-glucan, a ligand of CR3 (CD11b/CD18). Eur J Immunol 1991;21:1755–8.

108. Khorram O, Vu L, Yen SS. Activation of immune function by dehydroepiandrosterone (DHEA) in age-advanced men. J Gerontol A Biol Sci Med Sci 1997;52:M1–7.

109. Casson PR, Andersen RN, Herrod HG, et al. Oral dehydroepiandrosterone in physiologic doses modulates immune function in postmenopausal women. Am J Obstet Gynecol 1993;169:1536–9.

110. Caughey GE, Mantzioris E, Gibson RA, et al. The effect on human tumor necrosis factor alpha and interleukin 1 beta production of diets enriched in n-3 fatty acids from vegetable oil or fish oil. Am J Clin Nutr 1996;63:116–22.

111. Endres S, Meydani SN, Ghorbani R, et al. Dietary supplementation with n-3 fatty acids suppresses interleukin-2 production and mononuclear cell proliferation. J Leukoc Biol 1993;54:599–603.

112. Meydani SN, Endres S, Woods MM, et al. Oral (n-3) fatty acid supplementation suppresses cytokine production and lymphocyte proliferation: comparison between young and older women. J Nutr 1991;121:547–55.

113. Virella G, Fourspring K, Hyman B, et al. Immunosuppressive effects of fish oil in normal human volunteers: correlation with the in vitro effects of eicosapentanoic acid on human lymphocytes. Clin Immunol Immunopathol 1991;61:161–76.

114. Wu D, Meydani SN. n-3 polyunsaturated fatty acids and immune function. Proc Nutr Soc 1998;57:503–9 [review].

115. Kudsk KA, Minard G, Croce MA, et al. A randomized trial of isonitrogenous enteral diets after severe trauma. An immune-enhancing diet reduces septic complications. Ann Surg 1996;224:531–40.

116. Braga M, Gianotti L, Cestari A, et al. Gut function and immune and inflammatory responses in patients perioperatively fed with supplemented enteral formulas. Arch Surg 1996;131:1257–64.

117. Kemen M, Senkal M, Homann HH, et al. Early postoperative enteral nutrition with arginine-omega-3 fatty acids and ribonucleic acid-supplemented diet versus placebo in cancer patients: an immunologic evaluation of Impact. Crit Care Med 1995;23:652–9.

118. Alexander JW. Immunoenhancement via enteral nutrition. Arch Surg 1993;128:1242–5 [review].

119. Braga M, Gianotti L, Radaelli G, et al. Perioperative immunonutrition in patients undergoing cancer surgery: results of a randomized double-blind phase 3 trial. Arch Surg 1999;134:428–33.

120. Saffle JR, Wiebke G, Jennings K, et al. Randomized trial of immune-enhancing enteral nutrition in burn patients. J Trauma 1997;42:793–800.

121. Pichard C, Sudre P, Karsegard V, et al. A randomized double-blind controlled study of 6 months of oral nutritional supplementation with arginine and omega-3 fatty acids in HIV-infected patients. Swiss HIV Cohort Study. AIDS 1998;12:53–63.

122. Micke P, Beeh KM, Buhl R. Effects of long-term supplementation with whey proteins on plasma glutathione levels of HIV-infected patients. Eur J Nutr 2002;41:12–8.

123. Wong KF, Middleton N, Montgomery M, et al. Immunostimulation of murine spleen cells by materials associated with bovine milk protein fractions. J Dairy Sci 1998;81:1825–32.

124. Cross ML, Gill HS. Modulation of immune function by a modified bovine whey protein concentrate. Immunol Cell Biol 1999;77:345–50.

125. Minehira K, Inoue S, Nonaka M, et al. Effects of dietary protein type on oxidized cholesterol-induced alteration in age-related modulation of lipid metabolism and indices of immune function in rats. Biochim Biophys Acta 2000;1483:141–53.

126. See DM, Broumand N, Sahl L, Tilles JG. In vitro effects of echinacea and ginseng on natural killer and antibody-dependent cell cytotoxicity in healthy subjects and chronic fatigue syndrome or acquired immunodeficiency syndrome patients. Immunopharmacology 1997;35:229–35.

127. Melchart D, Linde K, Worku F, et al. Immunomodulation with echinacea—a systematic review of controlled clinical trials. Phytomedicine 1994;1:245–54.

128. Melchart D, Linde K, Worku F, et al. Results of five randomized studies on the immunomodulatory activity of preparations of echinacea. J Alt Compl Med 1995;1:145–60.

129. Cáceres DD, Hancke JL, Burgos RA, et al. Use of visual analogue scale measurements (VAS) to assess the effectiveness of standardized Andrographis paniculata extract SHA-10 in reducing the symptoms of common cold. A randomized double blind-placebo study. Phytomedicine 1999;6:217–23.

130. Cáceres DD, Hancke JL, Burgos RA, et al. Prevention of common colds with Andrographis paniculata dried extract. A pilot double blind trial. Phytomedicine 1997;4:101–4.

131. Bone K. The story of Andrographis paniculata, a new “immune system” herb. Nutrition & Healing 1998;Sep:3,4,8,9 [review].

132. Scaglione F, Ferrara F, Dugnani S, et al. Immunomodulatory effects of two extracts of Panax ginseng CA Meyer. Drugs Exptl Clin Res 1990;16:537–42.

133. Baranov AI. Medicinal uses of ginseng and related plants in the Soviet Union: Recent trends in the Soviet literature. J Ethnopharmacol 1982;6:339–53 [review].

134. Wagner H, Nörr H, Winterhoff H. Plant adaptogens. Phytomedicine 1994;1:63–76.

135. Bone K. Clinical Applications of Ayurvedic and Chinese Herbs. Queensland, Australia: Phytotherapy Press, 1996, 137–41.

136. Bone K, Morgan M. Clinical Applications of Ayurvedic and Chinese Herbs. Warwick, Queensland, Australia: Phytotherapy Press, 1996, 13–20.

137. Nanba H. Antitumor activity of orally administered ‘D-fraction’ from maitake mushroom (Grifola frondosa). J Naturopathic Med 1993;4:10–5.

138. Pengelly A. Medicinal fungi of the world. Modern Phytotherapist 1996;2:1, 3–8 [review].

139. Keplinger H. Oxindole alkaloids having properties stimulating the immunologic system and preparation containing same. US Patent no. 5,302,611, April 12, 1994.

140. Zhu JL, Liu C. Modulating effects of extractum semen persicae and cultivated cordyceps hyphae on immuno-dysfunction of inpatients with posthepatitic cirrhosis. Zhongguo Zhong Xi Yi Jie He Za Zhi 1992;12(4):207–9, 195 [in Chinese.

141. Nakamura K, Yamaguchi Y, Kagota S, et al. Activation of in vivo Kupffer cell function by oral administration of Cordyceps sinensis in rats. Jpn J Pharmacol 1999;79:505–8.

142. Stoner GD, Mukhtar H. Polyphenols as cancer chemopreventive agents. J Cell Biochem Suppl 1995;22:169–80.

143. You SQ. Study on feasibility of Chinese green tea polyphenols (CTP) for preventing dental caries. Chin J Stom 1993;28(4):197–9.

144. Hamilton-Miller JM. Antimicrobial properties of tea (Camellia sinensis L.). Antimicrob Agents Chemother 1995;39:2375–7.

145. Foster S, Chongxi Y. Herbal Emissaries: Bringing Chinese Herbs to the West. Rochester, VT: Healing Arts Press, 1992, 79–85.

146. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Foods, Drugs, and Cosmetics, 2d ed. New York: John Wiley & Sons, 1996, 350–2.

147. Hirazumi A, Furusawa E, Chou SC, Hokama Y. Immunomodulation contributes to the anticancer activity of morinda citrifolia (noni) fruit juice. Proc West Pharmacol Soc 1996;39:7–9 .

148. Herbert TB, Cohen S. Stress and immunity in humans: a meta-analytic review. Psychosom Med 1993;55:364–79 [review].

149. Palmblad JE. Stress-related modulation of immunity: a review of human studies. Cancer Detect Prev Suppl 1987;1:57–64 [review].

150. Kemeny ME, Gruenewald TL. Psychoneuroimmunology update. Semin Gastrointest Dis 1999;10:20–9 [review].

151. Halley FM. Self-regulation of the immune system through biobehavioral strategies. Biofeedback Self Regul 1991;16:55–74 [review].

152. Whitehouse WG, Dinges DF, Orne EC, et al. Psychosocial and immune effects of self-hypnosis training for stress management throughout the first semester of medical school. Psychosom Med 1996;58:249–63.

All Indexes
Health Issues Men's Health Women's Health
Health Centers Cold, Flu, Sinus, and Allergy Diabetes Digestive System Pain and Arthritis Sports Nutrition
Safetychecker by Drug by Herbal Remedy by Supplement
Homeopathy by Remedy
Herbal Remedies by Botanical Name
Integrative Options
Foodnotes Food Guide by Food Group Vitamin Guide
Become a Sales Superstar
Learn how to earn more by selling
more and closing with higher ratios