I thought I’d write something on our immune systems. Everyone’s doing it and I was feeling a bit left out! You may want to grab a cup of tea (and maybe a dark chocolate brownie). We’ve got a lot to talk about.

Of course, most of us are rightly concerned at the prospect of the dreaded virus reaching our vulnerable family members and friends, so we are naturally curious as to what might optimise our defences and give us and them the best chance of avoiding infection.

At the other extreme, I was fascinated to read about the over-activity of the immune system which doctors are seeing in some patients with the Covid19 virus, resulting in the catastrophic attack of various organs by the body itself. Not only is this concerning but evidence of the very fine line between an optimised immune system and a self-destructive one.

This is also why I struggle with the term ‘boosting’ when it comes to immunity. To me, it suggests the possibility of prompting our immune system to be super-active, exceeding its normal function, which is clearly something we wouldn’t want to do. Fortunately, I am fairly certain that this would be impossible, at least not via nutrition or supplements.

Something to bear in mind whilst we talk about the role of specific nutrients or foods, is that most studies are carried out on people who are already ill or who have a deficiency in a specific nutrient. Often these are carried out in the developing world where severe deficiencies in Vitamin A, for example, are endemic. In these cases, the researchers can then monitor blood levels or improvement in specific clinical signs and symptoms.

However, if someone is generally healthy, it is nigh on impossible to say whether the nutrient being tested is actually having any effect on their immune system at all.

What do the manufacturers measure? They would somehow have to prove that the compound led to a measurable biochemical change. Next, they’d have to carry out a study involving many people, giving half of them the nutrient and the other half a placebo and expose them all to a contagious pathogen of some sort, then monitor them. No one (except a computer) would be allowed to know who had received the nutrient and who had received the placebo until all the results were in. They would also need to ensure that enough people were involved in the trial to give any power to the results (it’s all about statistics). For those who like long terminology, this is called a randomised double-blind placebo-controlled trial and they are long and very expensive.

If we are talking about a Vitamin or other naturally occurring compound, you would struggle to get a patent, so who would bother spending all that money on research and development if anyone could just steal the idea? And here lies the problem with many supplements and alternative remedies.

However, just because something hasn’t undergone this rigorous testing, doesn’t mean it doesn’t work. I have every respect for ancient medicines and home remedies which we all swear by. If something seems to work for us, without causing potential harm or costing us more than we can easily afford, then why not continue. There is also great comfort in sipping a hot brew of something that our parents or grandparents always made for us when we were feeling a bit rough.

However, in this blog we’re talking about prevention, not treatment. To give this topic a bit of context, here is my two minute, non-scientist friendly immune system summary.

There are two parts; one we’re born with and one we acquire.

The one we’re born with (our innate immune system) is a bit like the hoards of police who respond at speed in their loud flashing cars to a reported burglary. They run around looking for likely suspects and block the roads to prevent a quick getaway. It’s a general mass response.

Similarly, our innate immune system rushes to the location of an injury or infection within minutes or hours, causing inflammation and randomly killing any attackers to prevent infection and generally making the environment unpleasant for the invaders. A fever, for example, is produced by our own body, not an infection, for this very reason.

Back to our burglary. The police then call in the detectives who arrive in their own good time. These specialists take hours looking for specific evidence to identify who exactly perpetrated the crime, comparing methods of break-in and descriptions of the culprits with their records. If they’re lucky they might get a match with a previous crime. ‘Yep. We recognise them, this is how they operate and we know where they live.’ On other occasions, they might draw a blank but they’ll file away some of the evidence they’ve gathered just in case this crew strikes again.

Our innate immune system also has a hotline to the specialists i.e. the acquired immune system, which arrives later (possibly days or even weeks later). It takes more time to mobilise our acquired immune system but, when it arrives, it compares the attackers with it’s memory of previous infectious invaders based on, amongst other things, markers on the surface of their cells. It either knows how to fight it or stores the information ready for the next time the same invader appears. This is largely driven by our thymus and the lymph system.

Of course, the more bacteria and viruses we’re exposed to across our lives, the more specific immunity we acquire, hence the apparent benefit for having pets to nuzzle and spending time outside eating mud as a child. And, of course, we can decide whether we have vaccinations or not. Eating mud into adulthood is not compulsory, or advisable!

Due to a child’s undeveloped immune system and tendency to share their ice cream with the dog, their thymus organ is at its most effective at this age. From then on, the thymus becomes gradually invaded with fat and less useful, hence the elderly have far weaker immune systems and vaccines tend to be less effective for them. Their acquired immune system is gradually losing its memory too!

We also have a very efficient barrier to stop infectious agents or toxins getting into our body in the first place – our skin. If intact, it keeps most things from getting further than the superficial layers. Even the annoying grease produced by our hair follicles is in fact protecting us by creating an acidic environment to repel invaders. In the hospital there was often a handcream dispenser next to the alcohol gel dispenser because, if you’re using a lot of alcohol gel, your hands can become chapped and the barrier broken. So, it’s a good idea to keep your hands moisturised.

Our mouth and nose are easy routes of entry for infections but we can reduce the risk of attackers getting in in the first place by washing our hands, wearing masks and all the other tiresome but essential practices we are being asked to do right now.

If we do happen to take harmful bugs in via our mouth, they get a thorough attack by our stomach acid but 75-80% of our immune cells exist in our gut and they put up a further fight

If you’ve read any of my blogs in the past you know I’m going to get onto gut health at some point. So, I won´t disappoint!

Have you ever heard of Peyer’s Patches? They´re not the type of patches you stick on your arm to help quit smoking or dispense HRT. They are in our gut mucosa (lining) and they are the equivalent of the police photo-fit computer. Peyer’s Patches consist of lymph tissue. They constantly monitor new arrivals into our gut and decide whether they are safe to be admitted further into the blood system based on previously acquired knowledge. (Amazingly the tonsils and the appendix contain similar types of monitoring cells which are particularly active in our early years.)

And, who keeps our gut mucosa healthy. Of course, our gut bacteria.

My previous blog, entitled ‘If you don’t use it, you lose it’ talks about the ever-growing evidence for links between greater variety in gut microbes and better health and how this requires a varied diet. In that blog I focussed on sportspeople but studies also show that elderly people living in long-term residences have a far less diverse range of gut microbes than those living at home. Furthermore, the range contains significantly fewer of the Bifidobacteria variety which seem to be a helpful bunch. More of the inflammation-related bacteria then take over which compromise the integrity of the gut lining and potentially affect all our bodily organs. Never more than now are we seeing the possible consequences of this.

Unfortunately, from the age of 50, the efficiency of both arms of our immune system takes a dive. The beautiful-sounding term for this, ‘Immunosenescence’, belies its sobering truth.

So, we need to look after our gut and that means a healthy diet with plenty of variety in fruit, vegetables and wholegrains to feed our bacteria.

But, it’s not just our gut microbes that need feeding to keep our immune systems strong, let’s not forget all those cells in our body that are doing the detective work and cross-checking marauders with photo-fits of known villains. They demand good nutrition too, as do the first-response troops of the innate immune system.

So, which nutrients deserve special attention?

Let’s start with Vitamin C. There is a lot of talk about Vitamin C in immunity. It not only helps the immune cells do their job gut also keeps our skin intact. One study showed that a daily supplement of 200mg a day reduced the duration of colds in a small percentage of adults and children but only by about a day. You’re unlikely to come to any harm with this dose but, if you can, it would be more useful to obtain it from food since you then get all the other accompanying health-promoting nutrients.

Excellent sources of Vitamin C are tomatoes, peppers, kiwi fruit, citrus fruit and brassica vegetables. However, in much of the Western world where vegetable and fruit intake is low, potatoes are one of the main sources.

These foods don’t have to be organic or hand-picked or sold at a wholesome looking garden shop, as wonderful as these places can be. If all you have access to or can afford is frozen, then rest assured that it will have been frozen within minutes of picking so probably contains more Vitamin C than the squashy carrot that’s been rolling around the bottom of the fridge for a week. Freezing doesn’t change the fibre content either. Yes, some mass produced veg does appear to have lower levels of certain nutrients than that which is grown organically but there is no place for food snobbery. We all just do our best.

Vitamin C is water soluble, so boiling the life out of vegetables is best avoided. However, if you’re making a soup, you’ll get the Vitamin C back in the liquid. We can only absorb about 400mg in our body, so taking high doses regularly just produces expensive urine! And, high doses of Vitamin C can prompt the production of calcium-oxolate stones in your kidneys and possibly liver. Food first every time!

Vitamin A is essential for the development of immune cells but, apart from in the poorest parts of the world, it is readily available in all diets. There is plenty in meat products but also ample in vegetables where it goes under the name of beta-carotene.

Zinc works alongside Vitamin A and there is some evidence that taking a zinc supplement, usually in lozenge form, may reduce the duration of a cold. However, side effects can be nausea and a bad taste in the mouth so, as with anything new, have a chat with your pharmacist before starting any regular supplementation to ensure you’re not taking more than you need for your age or health status.

Meat and dairy products are key sources of zinc in the wealthier parts of the world but some of the best sources are plant-based; nuts, seeds, beans, lentils, chickpeas, wholegrains, mushrooms, spinach; all of which will make your gut microbes very happy too by supplying them with fibre to ferment. Most importantly though, dark chocolate is a reasonably good source of zinc. In my professional opinion, that would include any squidgy home-baked goods that might contain dark chocolate too. The darker the better. My body must be swimming in zinc!

Vitamin E also has a role in modulating the effect of immune cells and is found in nuts, seeds, vegetable oils, pumpkin and some green leafy vegetables.

Both Vitamin A and E are fat soluble vitamins which means that they are stored in our body in fat. As a result, high intakes can be toxic, not just wasteful, so I would advise against supplementing at any higher dose than you might find in a multivitamin and please avoid supplementing Vitamin A entirely if you are pregnant. Better still, stick with food sources.

The immunity-promoting benefits of Vitamins A (and beta-carotene), C and E are partly down to their role as antioxidants. Antioxidants protect our cells, including our immune cells, from attack by free radicals. Free radicals are highly reactive and unstable compounds. Other antioxidants you may have heard of are lycopene, which exists in high amounts in tomatoes, anthocyanins found in dark red vegetables such as aubergines, grapes and berries or phenolic compounds you’d find in asparagus. Did I mention dark chocolate? It is also a good source of antioxidants.

Do we need to eat vegetables raw to get the full benefit?

Not necessarily.

I’d say that it is better to have the vegetables than not, no matter how they’re cooked.

Uncooked vegetables need to be cleaned well to avoid introducing any infectious contamination from the soil, compost and chemicals used, especially if being served to someone whose immune system is already suppressed due to ill health or age. Raw vegetables also require more chewing and are harder work for the body to digest.

Consequently, a raw food diet might not be appropriate for someone with a small appetite and/or chewing problems and who struggles to maintain their weight, as is the case with some elderly people, the very young or those who are unwell.

As to whether raw food contains more nutrients, well that depends on the vegetable and its antioxidants. Although you lose Vitamin C in any wet type of cooking, it is readily available in many fruit and salad vegetables. So, the loss from the vegetables that you prefer to eat cooked is unlikely to leave you wanting in Vitamin C.

Some vegetables do retain more antioxidants when raw, such as broccoli and bell peppers whereas tomatoes increase the availability of their antioxidant, lycopene, with cooking. Similarly, carrots and asparagus provide more phenolic compounds when cooked.

It is true that the natural enzymes on the skins of the vegetables are de-activated with cooking but our body produces its own very efficient enzymes to get to the nutrients the vegetables contain.

 I am like a broken record, I know, but variety is the key. So why not mix and match the cooked with the raw and the red with the yellow and, unless it’s medicine, never eat anything you dislike just because you think it’s doing you good. Life it far too short for that!

A vitamin which has had a lot of press lately is Vitamin D, with apparently strong views on both sides as to whether Vitamin D status or supplementation are related to the risk of contracting Covid19. The fact that those in care homes and ethnic groups with darker skin are at greater risk of low Vitamin D levels and have been disproportionately affected by the virus may suggest a link but it is equally possible that other health and socio-economic factors can explain the link. That doesn’t mean it isn’t worth discussing your need for supplementation with your doctor or local pharmacist if you think you may be running a little low on Vitamin D but self-prescribing megadoses of anything is potentially very dangerous.

Echinacea? In brief, it seems there are three different types of Echinacea and a large number of parts of the plant that may be used in supplements, hence study results are very varied. But, if you think it works for you, why not. A word of warning though. There is a slight possibility that some Echinacea compounds may interact with certain medicines so, again, chat with your local pharmacist before popping a supplement daily.

Turmeric, if eaten regularly in your meal may help prevent viruses from getting further than your gut. So, if it tastes good to you, why not add it in?

How about probiotics? If your gut bacteria has taken a bashing due to ill-health or a course of antiobiotics, then a daily probiotic for a few months could well be helpful. (If you are severely immunocompromised, however, check with your doctor first.) Probiotics don’t stick around after you stop taking them but they seem to prevent unhelpful bacteria from colonising your gut whilst your own good guys get breeding again. Choose a quality brand with as many strains of bacteria in it as possible. Live yoghurts, kefir, kombucha etc can also be excellent sources of good microbes.

Are there any other secrets which will give my immune system that extra push towards optimum function? Yes, there are 5 but they don’t come in a pot or a bottle or a sachet with a hefty price tag and dubious scientific credentials. In fact, apart from a varied diet and barriers like masks and intact skin, the 5 things which will give you the best fighting chance of protection from any infectious illness, are:

– Your genes. Some families just seem to be more susceptible and genes are likely to play a part. ‘My children are never sick!’ How often have you heard that and bitten your tongue?

– Regular exercise. In my previous blog, we saw how regular exercise impacts very positively on our gut health, quite apart from the benefits of being outside away from coughs, sneezes and germ-ridden surfaces.

– Sleep. It’s important to know when to stop and rest too.

– Stress-reduction. Easier said than done and you’ll know better than me what soothes you.

– Socialising. Yes, studies have shown that those who are more socially isolated have higher blood levels of certain inflammatory markers. They are permanently in fight or flight mode which impedes their immune function. So, if you do make some chocolate brownies, remember to share them around for the sake of your immunity and that of the lucky recipients. It’s a win win situation.