June 2003

Vol. 2     No. 6  

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SARS Protection – More than a Face Mask

Total Immune System Enhancement

Could SARS eventually be deadlier than the Spanish flu epidemic of 1919 that killed more than 50 million people?

Could the higher rate of death for victims of SARS in Western countries be due to their high-fat, meat- and dairy-based diet? 1 

SARS, or severe acute respiratory syndrome, which is caused by a virus, is making headlines worldwide – so you have most likely thought about how you might avoid becoming a victim.  A new Gallup poll reports that 43 percent of Americans are now worried about the disease.  Nearly a half a million web sites have been generated, selling protection – from face masks and disinfectants to nutrients.  As of the end of June, 8000 cases in 27 countries with 800 deaths have been reported.  (I realize these seem like paltry numbers when it comes to dietary diseases like diabetes, heart attacks, strokes, and cancer, but it has the potential to become a very big cause of death and suffering.)  Many health authorities are declaring victory over this virus – but don’t be so sure.  The future may be much bleaker than these optimistic and unsupported predictions, especially with the winter months of high infectivity approaching soon. 

Some people fear the SARS virus could become a worse epidemic than the Spanish flu of nearly a century ago.  Right now the SARS problem does not seem like such a serious threat, but microbes often adapt and change behavior in the process of spreading.  After an initial wave of spreading across the world, the Spanish flu virus became 10 times more virulent during its second swell.  There are some interesting comparisons between the viruses:

  • Both may have originated in China

  • Both began as diseases in animals and through mutation gained access to humans

  • Both are systemic illnesses, but involve primarily the respiratory system

  • Both are spread by coughing and close, casual, contact

  • Both spread more viciously during the winter months

  • Malnourished (who are often the poor) fare worse in both viral infections

  • SARS is deadlier, killing 10% to 15% of victims, compared to 3% for the Spanish flu

  • No effective medications are available for either virus

  • Quarantine is of very limited effectiveness – both are highly contagious before symptoms appear, and one person can spread the virus to many other people

Right now, not traveling to hot spots, like Asia or Toronto, Canada, seems to be very effective prevention, but very soon that strategy may not have value if the virus spreads into your neighborhood.  Wearing a face mask, gloves, and washing your hands are also very superficial approaches for protecting you and your family – and the fact that the virus lives on surfaces for several days will make it necessary to maintain this barrier-type protection all of the time and to strictly avoid cross-contamination.  Modern drug approaches have failed – the combination treatment of antibiotics, antiviral agents (Ribavirin) and steroids is essentially useless.

Of great interest is the fact that the death rate in Toronto is twice as high as the overall death rate, which reflects figures mostly from China (12.7% vs. 6.4%).1   Even with all the medical technology, hospitals, and drugs in Canada compared to China, people in Toronto are much worse off.  Does this mean the Chinese are healthier people, with stronger immune systems?  I think so.  The main difference between these two populations is their diet – the Chinese are living on a higher carbohydrate (rice), higher vegetable, lower-fat, lower-meat, lower-dairy diet than the people in Toronto.  The diet of Westerners inhibits their immune system. 

The newest figures predict 15 percent of the victims of this disease will die. Death rates vary by age: 6% among those 25 to 44; 15% in those 45 to 64; and 50% for people 65 and older. Obviously not everyone exposed catches this virus, and even fewer of those infected die from SARS.  Therefore, you want to do everything possible to be among the stronger people who resist becoming infected, or as a second choice, who survive. Your best chances to accomplish these goals are with your own innate strengths – by bolstering your immune system into a disease-fighting machine.

A healthy immune system works in an orchestrated way with many players defending the body against foreign invaders, like the SARS virus (a coronavirus).  Our skin and mucosal membranes provide a physical barrier.   In addition to acting simply as a barrier, these surfaces mount an inflammatory reaction against the invaders.  Unfortunately, this virus sometimes penetrates surfaces like the membranes of the eyes, nose, mouth, intestine, and airways (lungs).  Once the intruders are inside the body, cells that eat the invaders, called phagocytes, come into action.  Other cells, called lymphocytes and natural killer cells make antibodies and other substances that deactivate and kill the virus.  Your immune system will mount and sustain for weeks the battle for your life – until won or lost.  Right now you can make some decisions and changes that will favor winning.

The Young and the Elderly

People living at both ends of life – babies and seniors – are most susceptible to infections of all kinds and worse outcomes.  Exclusive breast-feeding for 6 months, followed by continued breast milk until 2 years of age with the addition of starches, fruits and vegetables is the best protection for infants. (No vaccines are yet available for SARS.) When mother is exposed to an infection her immune system makes antibodies and other anti-infective substances (IgA, lactoferrin, or lysozyme) that are transferred through her milk directly into the baby – whose intestine at this stage of life is permeable and able to absorb all of these disease fighters.2

As we age, the strength of our immune system declines, resulting in an increase in incidence of infections, cancer, and other diseases. To make matters worse, nutritional deficiencies that affect their immunologic vigor are found in one-third of the elderly in industrialized countries. Those at especially high risk of poor nutrition are the very old, poor and/or isolated persons.  Better nutrition for these people is no different than for people of other ages – they need a diet based on starches with the addition of fruits and vegetables.  However, in this age group, people with diabetes, and in persons in developing countries – all groups vulnerable to nutritional deficiencies – studies have shown improvement in their immunity with addition of vitamin and mineral supplements.3,4  In otherwise nutritionally adequate people, supplementation is at best a waste of money and effort, and at worst harmful.

Good Nutrition and Lifestyle is the Key to Effective Immunity

With a severe deficiency of food (calories) – starvation – the entire immune system can become compromised and this can lay the way for infection of the body by a great variety of microorganisms.  This means an overall deficiency of calories, protein, fats and all the other life-giving nutrients we gain from our foods.  Isolated deficiencies of micronutrients are rare, except for iron, vitamin A, and zinc. 

At the other end of the spectrum is the overnutrition that is so prevalent in Western societies, with as many as 65% of people being too over-fat for their own health.  This form of malnutrition also sets people up for infections and a poorer chance of survival once they’re sick.  Obesity has been shown to diminish the immune response.5  The data on weight loss improving immune response is, however, plagued with mixed results – and I believe this is because there are many ways to lose weight and some are very unhealthy, like high protein diets.

The best way to lose weight and improve the immune system is to eat a low-fat, plant-based diet.

A Plant-Based Diet Improves Immune Response

A recent study of ten middle-aged and elderly people with the slightly elevated cholesterol levels typical of many Americans showed a change to a low-fat diet (15% of calories) (not vegan) boosted their immune system.6  Reasons for this improvement are because these people lost weight, reduced their cholesterol levels,7 added vegetables and removed much of the immune system-suppressing fat from their diet.

Fats, Including Olive and Omega-3 Fats, Suppress the Immune System

All fats, and especially the “good” fats, suppress the immune system.8   This means all the added fat, not just animal fat, must go.  Olive oil,9 corn oil,10 and the omega-3 fats, like flaxseed oil11 and fish oil,11-13 must be removed to enhance immune function.

You know these so called “good” omega-3 fats suppress the immune system.  They are recommended to reduce the inflammation of arthritis and they work by causing a generalized suppression of the immune system.  This means that the immune system that fights off viruses, and suppresses cancer growth, is also depressed.

Fish Decreases Immune Function Too

You also need to remove the fish because of their anti-immune system effects.  A study of 22 subjects over 40 years of age fed a low-fat, high-fish diet was found to significantly decrease various parameters of the immune response; in contrast to this diet when it was low in fish.14 The authors concluded concerning fish consumption, “Such alterations may be beneficial for the prevention and treatment of atherosclerotic and inflammatory diseases, but may be detrimental with regard to host defense against invading pathogens.”

Low-Calorie, High-Protein Diets Harm Immunity

Even though obesity is associated with poor immune system function, do not try to repair the damage with a low-calorie, high-protein diet.  Twelve nondiabetic obese subjects were studied during a 6-week period of following a 400 calorie liquid protein diet. Significant decreases were observed in immune cells (total leukocytes, neutrophils, lymphocytes, and monocytes).15  The authors  wrote, “…the results of this study clearly justify some caution in the long-term use of these diets.”

There are other positive lifestyle steps you can take to bolster your immune system.

Coffee Suppresses Immunity, But Tea Benefits

Starbucks is going to be unhappy about this finding.  The effect of coffee consumption on the immune system, studied in 15 men and women, showed that functions of immunity were about one-third lower during a period of coffee drinking compared to a period of abstinence from coffee.16

However, tea is a great stimulant beverage.  Eleven healthy non-tea-drinking people were instructed to drink a tea made with one bag steeped for 5 minutes in 100 ml of boiling water.17  They were compared with 10 people instructed to drink 5 to 6 cups of instant coffee.  The tea, but not the coffee, caused the immune cells to become more effective at defending the body.  This effect was believed to be due to substances (alkylamine antigens) found in tea and plants that mimic the effects of protein found in microorganisms – and in this way they stimulate the immune system into action.

Alcohol Overuse is Detrimental

While malnutrition, vitamin deficiencies and advanced liver disease can compromise your immune system; alcohol itself is toxic to the system.  Chronic and even acute, moderate alcohol use can increase your susceptibility to infections.18 But moderation (too often defined in the eyes of the user) may not be so bad. There is some evidence that daily consumption of small amounts (one to two 6-oz glasses) may be beneficial for immune function.19

Too Much Sunshine Can Be Hazardous

Researchers calculated that approximately 100 minutes of solar exposure at around noon in mid-latitudes (Italy, Spain, Northern California, Pennsylvania) would suppress the resistance to infections by microbes  (L. monocytogenes) in the most sensitive humans.20  Some sunlight is essential, preventing vitamin D deficiency diseases, such as rickets.  Over 90% of our vitamin D comes from sunlight exposure.  The amount needed is very small.  For example, for a person with a moderately fair complexion, five minutes at noon, two to three times a week, of sun exposure on the face, hands and arms (6% to 10% of the body) in Boston in the spring, summer and fall is thought to be sufficient.  However, the amount of exposure varies with the skin pigmentation, latitude, and atmospheric conditions.  A six-fold increase for very black skinned people may be required for vitamin D synthesis.

The SPF rating of a sunscreen does not necessarily indicate whether it will protect from immune suppression.  The wavelengths that burn are different than those that suppress.  The best protection seems to be with those sunscreens that filter both UVB and UVA; and have a relatively high SPF value.21 You should also employ strategies of sun avoidance whenever possible, like wearing hats and other protective clothing and/or sunglasses.

Sleep Can Depress More than the Immune System

Sleep is believed to have a restorative function on the immune system – and prolonged sleep deprivation may suppress the immune system.22 However, one night’s sleep loss has actually been shown to increase the activity of the immune system.23 Therefore, short term sleep deprivation is not harmful to the immune function, but prolonged sleep deprivation may increase susceptibility to viral infections.

However, there is a balance between too much and too little sleep.  Too much sleep is known to cause mental depression24 and this may lead to worse health and increased risk of infection.25  Limiting the hours of sleep is an extremely powerful treatment for depression.24 Most healthy adults need 5 to 7 ½ hours a night.  Pregnant women, children and people who are ill need more sleep.

Strenuous Exercise Increases Your Risk of Infection

Moderate levels of exercise seem to improve the immune function, especially for the elderly.26 Unfortunately, intense exercise can severely depress the immune system and increase the risk of infection.  High intensity, prolonged bouts of exercise have been shown to increase the susceptibility to upper respiratory infections, and during the incubation period of an infection, exercise may worsen the disease outcome.  Researchers monitored levels of infection in more than 200 runners and rowers. They found the levels of infection were lowest in middle-distance runners, and highest in runners after a full or ultra-marathon and in elite rowers after intensive training.27,28

The Choices You Make Now May Keep SARS Away Tomorrow

Therefore, you do not have to sit idly waiting for SARS to happen to you.  You can make real choices right now that will make real differences in your future.  It is especially convenient that these choices for your immune system are the same ones you are making to prevent other potential future health tragedies, like heart disease and breast cancer – and they are cost-free, non-toxic, and side-effect-free.  So you have no reason to delay.


1) Editorial.  Will SARS hurt the world's poor?  Lancet. 2003 May 3;361(936  8):1485.

2)  Hanson LA.  The role of breastfeeding in prevention of neonatal infection.
Semin Neonatol. 2002 Aug;7(4):275-81.

3)  Barringer TA.  Effect of a multivitamin and mineral supplement on infection and quality of life. A randomized, double-blind, placebo-controlled trial.  Ann Intern Med. 2003 Mar 4;138(5):365-71

4)  Fawzi W.  A role for multivitamins in infection? Ann Intern Med. 2003 Mar 4;138(5):430-1.

5)  Lamas O.  Obesity and immunocompetence.  Eur J Clin Nutr. 2002 Aug;56 Suppl 3:S42-5.

6)  Santos M. Immunological effects of low-fat diets with and without weight loss.
J Am Coll Nutr. 20 03 Apr;22(2):174-82.

7)  Traill KN.  Lipoprotein interactions with T cells: an update. Immunol Today. 1990 Nov;11(11):411-7.

8)  Calder PC.  Dietary fatty acids and lymphocyte functions.  Proc Nutr Soc. 1998 Nov;57(4):487-502. 

9)  Yaqoob P.  Monounsaturated fats and immune function.  Proc Nutr Soc. 1998 Nov;57(4):511-20. 

10)  Kelley DS.  Concentration of dietary N-6 polyunsaturated fatty acids and the human immune status. Clin Immunol Immunopathol. 1992 Feb;62(2):240-4. 

11)  Meydani SN.  Oral (n-3) fatty acid supplementation suppresses cytokine production and lymphocyte proliferation: comparison between young and older women.  J Nutr. 1991 Apr;121(4):547-55. 

12)  Kelley DS.  Docosahexaenoic acid ingestion inhibits natural killer cell activity and production of inflammatory mediators in young healthy men. Lipids. 1999 Apr;34(4):317-24. 

13)  Kelley DS. Dietary docosahexaenoic acid and immunocompetence in young healthy men. Lipids. 1998 Jun;33(6):559-66. 

14)  Meydani SN.  Immunologic effects of national cholesterol education panel step-2 diets with and without fish-derived N-3 fatty acid enrichment.  J Clin Invest. 1993 Jul;92(1):105-13. 

15)  Field CJ.  Changes in circulating leukocytes and mitogen responses during very-low-energy all-protein reducing diets. Am J Clin Nutr. 1991 Jul;54(1):123-9. 

16)  Melamed I. Coffee and the immune system.  Int J Immunopharmacol. 1990;12(1):129-34. 

17)  Kamath AB.  Antigens in tea-beverage prime human V{gamma}2V{delta}2 T cells in vitro and in vivo for memory and nonmemory antibacterial cytokine responses.
Proc Natl Acad Sci U S A. 2003 Apr 28 

18)  Szabo G.  Consequences of alcohol consumption on host defence.
Alcohol Alcohol
. 1999 Nov-Dec;34(6):830-41. 

19) Diaz LE.  Influence of alcohol consumption on immunological status: a review.
Eur J Clin Nutr. 2002 Aug;56 Suppl 3:S50-3. 

20)  Garssen J.  Risk assessment of UVB effects on resistance to infectious diseases
Photochem Photobiol. 1996 Aug;64(2):269-74. 

21)  Ullrich SE.  Sunscreen effects on UV-induced immune suppression.  J Investig Dermatol Symp Proc. 1999 Sep;4(1):65-9. 

22)  Rogers NL. Neuroimmunologic aspects of sleep and sleep loss.  Semin Clin Neuropsychiatry. 2001 Oct;6(4):295-307.

23)  Matsumoto Y.  Total sleep deprivation induces an acute and transient increase in NK cell activity in healthy young volunteers.  Sleep. 2001 Nov 1;24(7):804-9. 

24)  Giedke H.  Therapeutic use of sleep deprivation in depression.  Sleep Med Rev. 2002 Oct;6(5):361-77.

25)  Shinkawa M.  Depression and immunoreactivity in disabled older patients.  J Am Geriatr Soc. 2002 Jan;50(1):198-9.

26) Woods JA.  Can exercise training improve immune function in the aged? Ann N Y Acad Sci. 2002 Apr;959:117-27.

27)  Woods J.  Special feature for the Olympics: effects of exercise on the immune system: exercise-induced modulation of macrophage function.  Immunol Cell Biol. 2000 Oct;78(5):545-53.

28) Castell LM.  Does glutamine have a role in reducing infections in athletes?
Eur J Appl Physiol Occup Physiol. 1996;73(5):488-90.


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