A robust immune system is the best way to care for your health as winter sets in. There is no one particular vitamin that will work miracles, but a good combination of key nutrients can help. Vitamins and minerals are found in the food we eat, therefore a well-balanced diet that is high in plant material and diversity is going to help you. There are also times when a supplement can be of assistance, due to a lack of food intake, stress and environmental issues.

So what are the immune-boosting nutrients and why do we need them?

Vitamin C – this is probably the most known nutrient. We need vitamin C as being human we are unable to synthesize this ourselves and therefore we need to get it from our food.

Vitamin C is an important antioxidant that helps regenerate other antioxidants such as vitamin E and glutathione. This helps to reduce the damaging free radicals. Vitamin C is also needed for various enzyme reactions and is a cofactor for both iron and copper.

As an antioxidant, it is heavily used in acute infections, as well as helping maintain both our innate (general response) and adaptive (targeted response) immune systems.

The therapeutic daily dosage of vitamin C

for an adult is between 250-3,000mg,
infants 0-6 months 25mg
and a child 7-12 years 30mg.

The recommended daily dose (RDI) for adults is 45mg. If you smoke then the RDI is higher as smoking depletes your vitamin C due to a higher quantity of free radicals from cigarettes.

Vitamin C is water soluble meaning that you can’t store it in the body and therefore must get it from the food we eat. If taking a supplement it is best taken on an empty stomach or at least 2 hours after eating.

Zinc – this mineral is a real workhorse and is required for many different functions. It is regulatory, functional and catalytic so it is a multi-purpose mineral.

It helps to regulate the immune system by way of T cell function along with mediating innate immunity. It assists with antibody production in the immune system. It is antioxidant and antiviral helping to regenerate vitamin E. It helps with the release of vitamin A (another immune-helping vitamin). And it assists with gut function, which plays a major role in immune function (see previous posts on gut health). So it is a very key nutrient for good immune health.

This is another nutrient that is not stored in the body therefore it must be consumed from food.

The RDI for zinc in an adult is 14mg. The therapeutic range is 10-90mg for an adult. Zinc is best taken on a full stomach or after food, as if you have a deficiency it can make you nauseous when taken on an empty stomach.

Vitamin D – is well known for its help with bone health. But it has many other purposes essential to good immune health.

Vitamin D assists with the modulation of T cells in the immune system. It helps to modulate the immune cascade to allow more anti-inflammatory products. Vitamin D can halt rapid cell division in pathogenic cells, therefore stopping them from reproducing and causing havoc.

Vitamin D also has a role in helping the gut lining and assists with good gut health and immune function. Vitamin D can help your essential fatty acids do a better job.

Vitamin D is best obtained through sunshine via absorption from the skin. You can try an app which tells you the best time of the day to get any Vitamin D. I use the dminder app.

Through winter here in Melbourne the ability to absorb vitamin D is diminished, so ensuring you are improving your intake via foods with vitamin D and probably supplementing is a good option.

The RDI for an adult for Vitamin D is between 200-600iu. The therapeutic range is between 400-4000iu for an adult. Most tablets are around the 1000iu.

Vitamin d is a fat soluble vitamin so is best taken with food for better absorption.

Selenium – is a trace element that can also be found in the soil and the food grown in that soil. There are parts of the world where selenium content is very low in the soil.

Selenium plays critical roles in reproduction, thyroid hormone metabolism, DNA synthesis, and protection from oxidative damage and infection. It modifies immune and inflammatory responses, enhances the function of both T & B cells and is a key antioxidant.

The RDI for an adult male is 70mcg and 60mcg for a female adult. This is a nutrient that can be toxic if taken in large doses, so anything over 200mcg should be prescribed by your health professional.

Vitamin A – this is probably the lesser known vitamin, essential for immune function. It is mostly known for improving eyesight, but it has so much more on it’s to-do list.

Vitamin A is broken into retinols and carotenoids as they different functions. Beta-carotene is converted to vitamin A in the intestine and supports immune function, vision and reproduction.

Retinoids are the biologically active form and are essential for cellular function, thyroid hormones, and the inner lining of many organs and activates those T & B cells.

Vitamin A is a fat-soluble vitamin so it is best consumed with food, especially another source of fat.

The RDI for vitamin A is 900-3000iu for an adult male and 700-2300iu for an adult female. The therapeutic range for adults is 10,000-50,000iu.

Caution is needed for high doses as it can lead to the risk of birth defects, liver damage and decreased bone mass. Another nutrient that should only be prescribed by your health professional for high doses.

Some other nutrients are worth mentioning, that can help with your immune function.

Quercetin – is a flavanol that is a powerful antioxidant. It has anti-inflammatory qualities that help modulate allergies. It assists with the absorption of vitamin C and modulates the immune function.

It can be used in upper respiratory conditions to help break down mucus.

It works synergistically with bromelain (found in pineapple), green tea and turmeric to help reduce inflammation.

Garlic - contains allicin (diallyl thiosulfinate) and is a highly potent natural antimicrobial substance. It inhibits the growth of a variety of microorganisms and has antibiotic properties.

Ginger -fresh ginger is effective against respiratory infections, including the common cold.

Mushrooms - especially shitake and maitake are both great for improving immune function due to their high levels of polysaccharides (which stimulate the immune system and control blood glucose levels)

Chicken Soup- there is lots of research behind this theory and it does help. Especially when loaded with garlic, onions, ginger, turmeric, carrots, sweet potato and chicken. See my recipe

Pre/Probiotics - these will assist with gut function and improve immune health. See my previous post on gut health.

As you can see there are lots of ways to help improve your immune function via food. The stand out vegetable is broccoli as it is mentioned in nearly every nutrient. Consuming lots of vegetables, fruit, nuts/seeds and quality protein is the best way to provide your body with the fuel it needs.

Stress is a factor in food and nutrient absorption. If you are tired and stressed your ability to absorb and utilise nutrients can be depleted.

_________________________________________________________

References

Gropper, S. S., & Smith, J. L. (2008). Advanced Nutrition and Human Metabolism (fifth edition). Cengage Learning.

Osiecki, H. (2014). The Nutrient Bible 9th Edition (Ninth). Bio Concepts Publishing.

Pitchford, P. (2002). Healing with Whole Foods: Asian Traditions and Modern Nutrition. North Atlantic Books.

Stephen Harrod Buhner. (2013). Herbal Antivirals—Natural Remedies for Emerging & Resistant Viral Infections. Storey Publishing.

___________________________________________________________________

This article was written by Jan Caton BHSc - Naturopathy. Jan is the owner, naturopath and nutritionist at Magnolia Apothecary.

Immune Health

Banana Oat Choc Chip Cookies

Bircher Muesli