Having a robust immune system is the best way to take care of your health in this current climate. While there is no one particular vitamin that will do this for you, a good combination of some 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 assist. There are also times when a supplement can be of assistance, due to a lack of food intake, stress and environment 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 then 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, along with 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. As a practitioner I use the therapeutic daily doses when prescribing.
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 work horse 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 also plays a major role in immune function (see previous posts on immune health). So 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 – this vitamin is well known for its help with strong bones. But it has many other purposes essential to good immune health.
Vitamin D assists with the modulation of T cells in the immune system as well as modulating the immune cascade to allow more anti-inflammatory products. It can halt rapid cell division in pathogenic cells and 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. While we are all isolated at home and the sun is still about, it is worthwhile getting out for at around 10-15 minutes per day to soak this up. You can try an app which tells you when the best time of the day is. I use dminder.
Through winter here in Melbourne the ability to absorb vitamin D is diminished, so ensuring you are improving you 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 then hence in the food grown in that soil. There are parts of the world where the soil content is very low.
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 both have 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, inner lining of many organs and activates those T & B cells.
Vitamin A is a fat soluble vitamin so 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 risk of birth defects, liver damage and decrease bone mass. Another nutrient that should only be prescribed by your health professional for high doses.
Quercetin – is a flavonol that is a powerful antioxidant. It has anti-inflammatory qualities that helps modulate in allergies. It assists with the absorption of vitamin C and modulate the immune function.
It can be used in upper respiratory conditions to help breakdown mucus.
It works synergistically with bromelain (found in pineapple), green tea and turmeric to help reduce inflammation.
There are also some other nutrients that are worth mentioning, that can help with your immune function.
Garlic – contains allicin (diallyl thiosulfinate) and is a highly potent natural antimicrobial substance. It inhibits 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- lots of research behind this 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 this topic.
As you can see there are lots of ways to 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. There is a lot of stress around at the moment and everyone is feeling it. If you are trying to diet and struggling then don’t worry. Now is about managing what you can. And looking after your health is a priority.
In these crazy times remember to be kind to yourself, by nourshing your body and taking care of you.
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.