How nutrition can help Covid-19 vaccination efforts

Chief Science Officer Dr Tara Swart explains how vaccines work, and how nutrition can have an impact.

The development of the Covid-19 vaccines has been one of the most remarkable efforts in recent medical history. Not only are they the first widely available vaccines to use mRNA technology, but the speed with which they were developed shows what can be done when we all get behind something. And make no mistake, a successful vaccination programme will go a long way to getting things back to normal.

Sars-Cov-2, better known as coronavirus, is new to humans. That means we have no natural immunity to it, and it’s part of the reason for the rapid spread of the virus. Previously, the only way to gain immunity was to catch the virus, but now we have a vaccine, and can build immunity that way. You can guess which one is preferable.

It’s important that we now do everything we can to ensure the vaccination effort is as effective as possible. And believe it or not, nutrition can play a role.

Covid-19 nutrition and obesity

While BMI is a one-dimensional statistic, there has been some evidence to suggest a correlation between the severity of a Covid-19 infection and being overweight. Current data shows that overweight people are suffering more, and are taking longer to recover from Covid.

Maintaining your regular physical health is the first step to protecting yourself from the virus. It’s not the only factor, but it’s a start. They key is to get gentle, moderate exercise, alongside a well-balanced diet. Moderation is important here—hard-core exercise lowers your immunity for a short period of time, and puts a huge amount of pressure on your body, so for most people, less intense but more regular exercise is the way to go. Don’t overdo it though—a brisk half-hour walk will do.

Why are vaccines effective

The immune system is an incredibly complex thing, but it can be broken down into three main parts: physical barriers, innate immunity, and adaptive immunity. I’ll focus on the last one.

A combination of immune cells, or lymphocytes (which include B cells T cells and natural killer cells ), work together with antibodies to disable and dispose of foreign pathogens. There’s a lot of depth you can go into, but I’ll try to keep it simple.

The adaptive immune system is relatively slow to spring into action, but once it does, it’s remarkable. Whereas innate immunity is quite a general process, adaptive immunity is highly specific, with different cells tailored to different pathogens. It goes something like this:

  • Lymphocytes (B and T cells) recognise a pathogen

  • Some T cells (CD4+, if you want to get technical) create chemical signals called cytokines

  • Cytokines tell B cells to make antibodies to neutralise the pathogen

  • Other T cells (CD8+) directly attack infected cells

  • Once the pathogen has been conquered, your immune system creates memory B and T cells

These memory cells stay dormant until the body next comes into contact with the same pathogen, at which point, they are released, and produce the same immune response as before, but much more quickly.

This immunological memory can last for decades, and is the reason that vaccination works . In exposing a patient to a small amount of the pathogen, it gives them the chance to build up antibodies and memory cells, so that any infection in the future is dealt with promptly.

There are many different types of vaccine, and many of them use different technologies, but they all have the same goal of creating immunological memory.

How nutrition affects the immune system

There are a lot of factors that influence the immune system, one of which is nutrition. Low nutrient levels can also undermine vaccine strength and efficiency. This is because they slow the production of B and T cells, rendering an immune response less effective, and giving the pathogen a longer period of time to take hold. This is even more pronounced in older patients, who typically demonstrate lower levels of lymphocytes .

The correlation between diet and immunity has been studied for centuries, but has mostly focused on vitamin C. It feels intuitively correct that healthy nutrition contributes to a strong immune system, and more recently, there’s been extensive research into other nutrients.

Randomised controlled trials show that supplements of certain micronutrients (in this case vitamins B6 and E, and selenium) all increased immune responses in older patients. There’s also research suggesting certain low nutrient levels can have a negative effect on vaccination. For example, low levels of vitamin D have been shown to inhibit vaccine responses in multiple types of flu strains.

Let’s take a look at some nutrients, and what they do to help your immune system against Covid-19.

Key nutrients for immunity

Vitamin A

One of several vitamins that aid antibody production (and is therefore vital for vaccine effectiveness). It also promotes natural killer cell activity, contributing to antiviral defences.

Dietary sources: cheese, eggs, oily fish

B vitamins

Specifically B6, B9, and B12. They also support natural killer cells, along with T cells. In older people, low nutrient levels have been shown to correlate with lower lymphocyte levels, slowing down the adaptive immune response.

Dietary sources: meat, eggs, nuts, broccoli

Vitamin C

Contributes to the production of antibodies, natural killer cells, and T cells, while also maintaining the epithelial cells (part of your body’s natural barrier to infection). Supplementation of vitamin C is also associated with shorter, less severe cases of respiratory tract infections (like the common cold). However, we need to be cautious of the popularisation of extremely large doses of vitamin C. The processing and excretion puts a lot of pressure on your body, at a time when it is already under pressure

Dietary sources: citrus, peppers, brussels sprouts

Vitamin E

Supplementation in over-65s has been shown to increase antibody production post-vaccination. This makes it particularly important when we’re looking to increase vaccine effectiveness.

Dietary sources: Olive oil, nuts and seeds, wheatgerm


Low Iron levels has been shown to reduce the output of T cells, and lower natural killer cell activity. However, overdoses of iron have also been shown to have a negative impact on the immune system, so it’s important to keep an eye on your intake and not go over the top.

Dietary sources: red meat, pulses, nuts


Has an important role in antiviral defence, inhibiting RNA polymerase that viruses like the coronavirus need to replicate. Low Zinc levels can also lower antibody production, leading to a less effective immune response.

Dietary sources: shellfish, dairy, eggs


As is the case with other nutrients here, low Selenium levels can affect lymphocyte function and antibody production. In the past, selenium supplementation has also been shown to improve the immune response to vaccination, though not enough is known about whether this will be the case with the Covid-19 vaccine.

Dietary sources: brazil nuts, fish, meat

Omega 3

Much like vitamin D, omega 3 has been associated with mitigating the effects of the cytokine storm. This may help reduce the irritation of cells often present in severe cases of Covid-19.

Dietary sources: seaweed, oily fish

(Data from the BMJ and NHS )

Are we getting the right nutrients for peak immune function and vaccine efficacy?

So if nutrition is important in both the vaccination efforts, and the function of your immune system against Covid-19, it’s vital that we take a deeper look. There’s a consensus that large parts of the population display low levels of various key nutrients, and this is especially the case among older people .

How to improve your nutrient intake

In an ideal world, we’d all eat a fantastic range of healthy food, which would provide us with all the nutrition we need. However, that would represent a large change for many people, and is unlikely to be sustainable. Getting the right nutrition isn’t a short-term fix, so a drastic change that we can’t stick to isn’t likely to be helpful.

Supplements are another option, and are probably more realistic for many people. Questionable multivitamins have given them a bad name in the past, but any dietitian will tell you that they can play a key role in a healthy body and brain. The NHS, for example, recommends that everyone take vitamin D3 supplements every winter (and during lockdowns, when we’re more likely to spend longer indoors).

The key to getting the right nutrition is habit. No supplement will do anything if you take it intermittently, and only eating a balanced diet one day a week will be just as ineffective. Something that you can easily incorporate into your routine, without extra hassle is likely to have more of an impact. And with regards to the vaccine, it’s important to take a supplement for an extended period both before and after the jab. Again, we’re looking to address underlying low nutrient levels in the long-term, so sustained action is key.

Get the Covid-19 vaccine

Still with me? I hope so—the next phase in the pandemic is crucial. Reaching a level of vaccination across the population is necessary to be able to return to some semblance of normalcy as safely as possible. Vaccination has a rich history of working , on everything from smallpox to measles, and it’s our best strategy for ending this.

About the author:
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Dr. Tara Swart

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