health
F
ortunately, immunity to viruses
is generalizable, and strong
immunity helps to protect us
against all viruses. A healthy
lifestyle with sound nutrition will not
only protect us against cold and flu,
but also yield multiple other health
benefits, such as delaying ageing and
enhancing the quality of life.
A healthy diet is a cornerstone of
good health. With modern farming
practices food has become less
nutritious, therefore, eating well is even
more important. A diet rich in healthy
meat, fish, vegetables and fruit will
usually deliver sufficient micronutrients.
Junk food, refined cereals, sugar and
sweet drinks (including fruit juice)
contain high levels of sugar and add
little nutritional benefit. GovHK has
their recommendation and guidelines
to the importance of a balanced diet 1 .
In this article we focus on four
micronutrients and a supplement that
are helpful for good immunity. These
are Zinc, Selenium, Vitamin D, Vitamin
C and Probiotics.
Zinc is a trace element. The daily
requirement is about 15mg. Zinc is
used by 300 different proteins in the
human body and it is essential for
normal immunity. Zinc deficiency is
common and affects as many as 2
billion people worldwide 2 . Many studies
have shown that Zinc deficiency causes
poor immunity. Other symptoms of Zinc
deficiency include hair loss (often after
child birth) brittle nails and poor taste.
Children may have white spots in their
nails. Supplementation with Zinc is safe,
although after many months Copper
levels may fall.
Selenium is also a trace element;
the daily requirement is 50mcg.
Selenium is used in antioxidant
proteins and is needed for normal
immunity to viruses. We have tested
large numbers of patients’ Selenium
and found deficiency to be common
in our population. This is probably
because the soil in China is low in
Selenium and therefore food produced
in China is also low in Selenium.
Supplementation with Selenium in
modest doses is safe with no long-term
negative consequences 3 .
Vitamin D is the sunshine Vitamin. It
is produced by the effect of sunlight on
our skin. Naturally Vitamin D levels fall
in the winter, which is also the flu virus
season and the season for Coronavirus
outbreaks. Many studies have shown
that Vitamin D is important for normal
immunity and that supplementation
can decrease the likelihood of virus
infections, including flu 4 . Deficiency is
Zinc deficiency
is common and
affects as many
as 2 billion people
worldwide 2
very common in our population and
supplementation improves immunity
along with multiple other health benefits 5 .
Supplementation without testing is safe
at lower levels such as 1,000iu daily for
children and 2,000iu daily for adults. If
in doubt please consult your GP and
consider testing for it.
Vitamin C is helpful to prevent and
treat viral infections. Supplementation
has been shown to shorten the
duration of the common cold 6 . All
people have a limit to the amount of
Vitamin C that can be taken by mouth
without causing stomach upsets.
However for adults, 6gm spread
over a day during a virus illness is
usually tolerated. Unlike Vitamin D the
duration of the effect of Vitamin C is
short lived so supplements must be
taken regularly.
In modern life our diet, antibiotics
and hygiene have altered our
microbiome - bacteria that live with
us in and on our bodies. The change
of gut microbiome has been shown
to have many negative health impacts
on our immunity including allergies,
digestive issues and autoimmune
diseases. Fortunately medical research
has shown that taking simple probiotic
supplements can help strengthen our
immune system 7 . In one study a simple
combined daily probiotic supplement
in children decreased antibiotic usage
by 84 per cent and episodes of
feverish illnesses by 72 per cent 8 .
Psychological stress is a key
cause of poor immunity. When we
are stressed we trigger our flight and
fight reaction, which was developed
while we were evolving to deal with
an immediate physical threat. In
modern life most of our stressors
are actually psychological such as
work, relationships or threats and
anxiety caused by health concerns
and, rather than being immediate, the
stress can persist for a long period of
time. As a consequence of the fight
and flight, all systems for long-term
health are downgraded to allow
resources for the immediate threat.
Therefore levels of Sex Hormones
and Growth Hormones will fall and
the stress hormones adrenaline and
cortisol will rise. Pulse and blood
pressure will rise. Appetite and
digestion will be downgraded. The
immune system will switch its focus
from surveillance for viruses and
cancer to the immediate threat of
bacterial infection from injury 9 .
Prolonged exposure to adrenaline
causes high blood pressure, anxiety
and poor sleep. The gut effects cause
ulcers and irritable bowel syndrome.
The immune effects make us more
vulnerable to viral infections. Other
psychological effects include an
inability to see the big picture and poor
short-term memory. Fortunately one
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