Hello

							                       When stress spells trouble for your gut
                How eating the right foods can protect the immune system
                          against the harmful effects of stress

Toronto, (August) 2009 – It's back-to-school time and already Canadians are waxing
nostalgic about summer holidays, lazy evenings around the patio and lighter workloads.
With schedules filling up, workdays getting longer and leisure time shrinking by the
minute, it's no wonder Canadians' stress level may peak at this time of year. Therefore,
finding ways to cope with stress becomes particularly important. Most Canadians are
familiar with symptoms of stress such as anxiety, muscular tension, difficulty
concentrating and insomnia. However, many don't suspect that stress can also put their
immune system at risk. Perhaps even fewer are aware that what they eat everyday can
make a vital difference between a healthy or a weakened immune system.

Stress and the immune system
Some stress is normal and can even be beneficial1, giving us the energy and motivation
needed to complete certain tasks. In fact, studies have shown that the immune system
responds to emergencies by temporarily boosting the body's natural defenses2. This was
particularly useful in humans' early history, when the ability to respond to acute stress
could mean the difference between life and death, known as the “fight or flight"
mechanism.

However, humans today are rarely confronted with fight-or-flight situations. Their
modern lifestyle has brought about a different kind of threat: long-term, sustained stress.
This can have physical and emotional consequences that, if not addressed, can steadily
wear down the body and spirit. Indeed, over 300 scientific studies have established a
relationship between psychological stress and the body's immune system3. Chronic,
sustained stress activates the central nervous system, which in turn suppresses the body's
ability to defend itself, through a complex set of signals and pathways.

Once the body's natural defenses are weakened, it becomes more vulnerable to illness,
and its ability to heal wounds can be compromised. The body then cannot adequately
defend itself against common microbes and viruses such as colds and various infections.

The vital role of food in stress management
Although regular exercise and adequate rest can help reduce stress, eating a healthy diet
is essential to reducing symptoms of stress and boosting the body's natural defenses.
Some foods can help reduce stress and even stimulate natural defenses, whereas others
should be avoided or consumed in moderation.

For example, foods that contain omega-3 fatty acids, such as salmon, sardines, tuna and
DHA-enriched yogurt, play a key role in stress management. Foods containing

1
  CCOHS: Workplace Stress fact sheet
2
  Segerstrom & Miller, 2004. Psychological Stress and the Human Immune System: A Meta-Analytic Study
of 30 Years of Inquiry. Psychological Bulletin, 130, 4
3
  Id.
antioxidants, such as blueberries, sweet potatoes, bell peppers and broccoli, neutralize
free radicals, which are produced in higher quantities when the body is under stress. On
the other hand, substances such as caffeine and alcohol can aggravate symptoms of stress
and disrupt sleep patterns.

Foods that boost the body's natural defenses
Certain foods have the ability to stimulate the body's natural defenses. This makes sense,
given that the intestine is the body's main line of defense, producing from 70% to 85% of
the body's immunitary cells4. Sweet potatoes, carrots, kale and spinach all contain beta-
carotene, which increases the number of infection-fighting cells. Special attention should
also be paid to foods containing zinc, since a deficiency in this nutrient can impair white
blood cells, an essential component in the body's defense system. Finally, a few products
specially designed to boost the body's immunity have appeared on store shelves in recent
years, particularly probiotic yogurts.

For example, Danone's DanActive, a probiotic yogurt containing 10 billion L. casei
DefensisTM bacteria per bottle, has been proven to help strengthen the body's natural
defenses, when consumed daily. DanActive’s effectiveness is supported by over 25
scientific studies, including several clinical trials. More than 37 studies have contributed
to further scientific proof showing the positive effects of DanActive on the body's natural
defenses. In periods of heightened stress, Canadians should pay special attention to their
emotional and physical well-being by eating a healthy diet, getting regular exercise and
adequate rest.

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4
    Stimulez votre système immunitaire. Isabelle Huot, Denis Roy, Les Éditions de l'Homme, 2008.