Vitamin C is often called the master immune nutrient, because of its essential role in
immune function. It is required to nourish the thymus gland (the master gland of the
immune system). Among other relevant effects, vitamin C increases white blood cell
function, interferon production and antibody activity. One recent review of sixteen
studies found that, on average, those who supplement vitamin C experience 34% less
days of illness per year.
Zinc is a primary nutrient in immune function, particularly due to its beneficial effects
on thymus gland function and white blood cell function. It is also required for the
liberation of stored vitamin A from the liver.
Vitamin A and beta-carotene are helpful in supporting immune function in the mucous
membranes and therefore preventing infection. As the weather gets colder the body
becomes less able to utilise supplies of vitamin A perhaps explaining why colds are
more prevalent in the winter. Vitamin A supports thymus gland health, strengthens the
mucous membranes of the nose and throat (making them less susceptible to infection),
and supports immune cell function.
Vitamin D is a potent immune system modulator. There is considerable scientific
evidence that vitamin D has a variety of effects on immune system function and may
enhance innate immunity and inhibit the development of autoimmume diseases.
Although a lack of any essential nutrient will impair immune function, a selenium
deficiency is especially detrimental. Research demonstrates that low selenium status is
associated with weakened function of the thymus (the master gland of immunity) and
suppressed white blood cell activity. It has also been established that selenium
supplementation promotes immune function, as highlighted in a 1994 study showing
that 200ug of selenium per day increased natural killer cell activity by more than 80%
and the ability of lymphocytes to kill abnormal cells by almost 120%.
White blood cells are an essential part of the immune system because their job is to
defend the body against foreign invasion. Several studies have found that AC-11
increases white blood cell (WBC) counts. A randomised human intervention study in
23 men found that those who took 350mg of AC-11 twice a day for two months
experienced statistically significant immune enhancement compared to controls, with
higher total WBC counts and enhanced lymphocyte to neutrophil ratios.
The impact of stress on the immune system can be significant, weakening immune
defences and increasing the likelihood of infection. Rhodiola is an adaptogenic herb,
meaning it improves resistance to stress, as well as having direct immune supportive
properties. Rhodiola has been shown to increase the activity of certain immune cells,
Flu and Infection Summary
Nutrient/Herb Typical intake range
Vitamin C 1 1000 – 3000mg per day ( Increase during
Zinc2 15 – 30mg per day
Vitamin A3 5000 – 10,000IU per day
Vitamin D 400 - 2000IU per day
Selenium4 50 – 200ug per day
AC-115 350-700mg per day
Rhodiola rosea extract6 250 – 750mg per day
The above nutrient intakes should be adjusted if a multi vitamin/antioxidant formula is also
Identify and avoid potential allergens
Fruit (especially berries)
Nuts and seeds
Ensure sufficient protein in the diet
Minimise impact of stress – utilise stress management techniques
Wash hands to avoid hand-to-nose infection (most common route of infection)
Get adequate sleep and rest.
1. High intake of ascorbic acid associated with loose stools. High doses may interfere with
Warfarin. High doses should be avoided by those with kidney disease, kidney stones or those
with sickle cell anaemia.
2. May cause nausea on an empty stomach. High doses (>100mg per day) may suppress the immune
system. Ensure sufficient copper and iron intake with zinc supplementation
3. Do not use more than 2500IU during pregnancy. Long term high doses may result in toxicity.
High levels not suitable for those with kidney disorders.
4. Yeast-bound selenium should not be used concurrently with MAO anti-depressant medication.
Yeast-free supplements can be used as an alternative.
5. Do not use during pregnancy or lactation
6. Do not use during pregnancy or lactation. Concurrent use with anti-depressant medication under
medical supervision only.g natural killer cells and B-cells and is associated with improved infection