The role of nutrition in immune function

Posted by Jackson Peos in Immune Support

Estimated reading time: 11mins

The role of nutrition in immune function

In times of a pandemic, such as the one we are going through now, a healthy and functioning immune system is paramount. We must also remember that a resilient immune defence system won’t just bolster your chances of avoiding the virus or remaining asymptomatic, but it will also reduce the time of infection (if you are unfortunate enough to become symptomatic) subsequently reducing your risk of spreading the infection to others, particularly to the elderly who might not be as equipped as yourself when marching into battle with the COVID-19 virus.

Threats to our immunity: gym closures and strict social distancing measures

It’s also important to point out, that we - as a nation - are facing several challenges that have the capacity to deteriorate our immunity. Our ability to exercise (particularly weight training) and get outdoors for fresh air has now been hindered with recent gym and fitness centre closures and strict social distancing measures. We, of course, know that moderate-intensity exercise is beneficial to our immune system for several reasons.

  • Exercise causes changes in white blood cells and antibodies, resulting in a more rapid circulation which may detect (and consequently fight) diseases earlier.
  • The increase in body temperature from exercise may prevent the bacteria from multiplying and may bolster the fight against infections (similar to what happens when we have a fever).
  • Exercise can slow the release of some stress hormones (as long as the intensity isn’t too high), with high levels of some stress hormones known to increase the chance of illness.
  • Exercise may also help to flush bacteria from the lungs and airways.
With gyms having to shut shop, having a home gym setup is better than ever. If you aren’t so lucky as to have a home gym, ensuring you move your body each day is what is most important.
With gyms having to shut shop, having a home gym setup is better than ever. If you aren’t so lucky as to have a home gym, ensuring you move your body each day is what is most important.

Threats to our immunity: grocery restrictions

I’m sure at one time or another during this past two weeks we’ve all struggled to find a necessary grocery item, whether that be toilet paper, hand sanitiser, chicken or rice. These unprecedented times have caused panic among many, with that panic comes preparation for the worst. Many foresee harsher lockdown laws in the future (which may very well happen) that may threaten our ability to take trips to the grocery store, for suppliers to fill grocery store shelves, and the capacity for the food industry to operate. As such, the public has attempted (often selfishly) to over-purchase foods and provisions to supply the next 3-6 months, leaving at times sparse options for the rest of us.

Going to the supermarket recently I’ve noticed a massive hit to fresh produce. Lean meats are hard to come by, wholegrain shelves are often empty, and fruits and vegetables are few, and now overpriced. What isn’t scarce, is chocolate, ice cream, chips and lollies. If we went to the store and just purchased what was most available in this current environment, the result in the basket would look something like a show bag at the Royal Show. We have a recipe here for a reduction in our intakes of micronutrients, whole foods and protein, and an increase in ultra-processed, micronutrient-poor, trans-fat containing foods. While this change in eating behaviour not only threatens our ability to retain our muscle mass, remain at a healthy body fat level without nutrient deficiencies, but it also presents a massive risk to our immune system.

How your diet affects your immune function

Research shows that poor nutrition choices and protein deficiency both result in impairment to humoral and cell-mediated immune function. Additionally, evidence from weight loss trials also suggests that low energy intake can interfere with healthy immune function. So how can we then structure our food behaviour during this time to prevent a compromise in immunity?

Prioritise protein intake

Low protein intake is known to interfere with our immune system and our resistance to infection or disease because most immune mechanisms actually rely on the production and replication of active protein compounds. So, a lack of essential amino acids (the building blocks of protein) can result in an impaired response by the humoral immune system, immunity mediated by our extracellular fluids which secrete the antibodies to fight the virus!

Ensure your meals include a lean protein source and if your meal is low in protein, why not add a delicious Bulk Nutrients protein shake?

Supplementing glutamine and arginine may provide support

Over the past 10 years, Glutamine has been studied heavily for its ability to promote immune cell proliferation and immune function. In several trials, it was shown that glutamine supplementation can reduce infection and recovery time. In one study the inclusion of glutamine in a sports drink decreased the incidence of infections (cold, sore throat, flu) in marathon runners. I think it’s fair to say that glutamine may be effective, particularly for those already infected, for supporting immune function.

L-Arginine supplementation has been shown to increase blood lymphocyte proliferation and reduce T-cell numbers. Arginine is also the precursor of nitric oxide, an important microbicidal molecule involved with macrophage killer function. Daily supplementation MAY enhance your ability to fight infection.

Make sure you get enough protein, low protein intakes can interfere with the immune system and the body’s ability to fight off infection.
Make sure you get enough protein, low protein intakes can interfere with the immune system and the body’s ability to fight off infection.

Vitamins are essential

Ensuring you attain a wide range of vitamins and minerals (from a diet rich in whole foods if possible) will help support your bodily functions and the body’s ability to fight off infections.

There is convincing evidence for the role of vitamin A in fighting infections, as well as the negative impacts of vitamin A deficiency on immunity. Several trials have confirmed that a lack of vitamin A can cause immune alterations that increase the incidence of infectious disease, and death. Additionally, vitamin A supplementation in these cases to correct a deficiency has been shown to reduce the severity of symptoms from the infection.

Vitamin E functions as an antioxidant for the protection of our cells against oxidative damage. Controlled trials in both elderly and healthy young participants have demonstrated an enhancement of immune function with vitamin E supplementation.

Despite widespread coverage by the media of vitamin C as a combatant against the common cold, research on vitamin C to support immune function is actually quite unclear. The largest meta-analysis to date on human studies involving supplementation of vitamin C only showed immunity improvements in individuals with the lowest initial intakes of vitamin C.

In summary, the effects of vitamin A deficiency on immune function are significant and should be avoided. Additionally, there is some evidence that vitamin E and C may enhance the immune response by reducing oxidative stress. A diet compromising a high variety of different coloured fruits and veg will be your best strategy for avoiding the above vitamin deficiencies. If it becomes a time where all our fruits and veg aren’t available, it may be wise to invest in a multivitamin supplement to cover your bases.

We have a great range to choose from here at Bulk Nutrients. Green Fusion and Red Fusion are 100% natural vitamin and mineral powders that support energy levels and immune function, or for an easy all-in-one, I’d recommend checking out Proviotic Capsules.

Fatty acids are important too

Fatty acids affect immune function not only by the total amount of fat in the diet but also by the ratio of omega-3 and omega-6 fatty acids. Experimental studies have shown that the functional properties of immune cells can be modified by supplementation with omega-3 fatty acids via fish oil or linolenic acid. However, in some studies, authors have suggested that immune function may actually be improved with a reduction in total fat intake. Thus, don’t use this time to get lazy with your diet and slump to more “junk” style foods. Letting your daily fat intake creep up, particularly if it isn’t from omega-3 fatty acids, has the potential to hurt your immunity.

Eat the rainbow! Centre your diet around whole foods and fresh produce to ensure you’re getting a good spread of vitamins and avoiding vitamin deficiencies.
Eat the rainbow! Centre your diet around whole foods and fresh produce to ensure you’re getting a good spread of vitamins and avoiding vitamin deficiencies.

Avoid an iron deficiency

Mechanistic data suggests that both iron deficiency and iron excess can increase the chances of infection. However, it’s also important to note that there is a fairly large range of iron intakes to which the body can function normally. With that said, if these times are being accompanied by a big drop in your red meat and green veg intake and you don’t think you can rectify it with better eating behaviour, it might be worth looking into an iron supplement.

Zinc is essential for immunity

Zinc is the most important mineral for immune function. Zinc deficiency is known to cause decreased T-cell function, impaired antibody response and depletion of macrophages and lymphocytes. Luckily for us, required intakes for zinc are relatively easy to achieve through a balanced diet. So as long as you haven’t slumped to the Twisties and Twinkies diet, you’ll be ok.

For a daily dose of Zinc you can’t go past Bulk Nutrients ZMA Capsules, they contain zinc, magnesium and vitamin B6 and together provide support for sleep, recovery and immune function.

Nutrition for immunity defence

To sum up, these are the key takeaways to keep your body healthy and immunity strong...

  • Exercise causes changes in white blood cells and antibodies, resulting in a more rapid circulation which may detect (and consequently fight) diseases earlier.
  • Keep your protein intake high. If lean meats and dairy are hard to come by, supplement with whey or casein protein powders.
  • Don’t take your calories too low. This probably isn’t the best time for a fat loss phase.
  • Glutamine and l-Arginine supplementation may bolster your immune defence.
  • Consume a broad array of multicoloured fruits and vegetables to prevent any chance of vitamin deficiencies, particularly vitamins A, C and E.
  • If fruits and veg are hard to come by, look into a multivitamin supplement. Browse the complete range of Bulk Nutrients immune support supplements for the highest quality and best price.
  • Keep daily fat intake low to moderate, but with high consumption of omega-3 fats.
  • While deficiencies are rare, zinc and iron deficiencies can seriously compromise immunity. If you think you are at risk, it may be worthwhile to look at supplementing these minerals.


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