As we face down yet another season of sniffles, staying healthy may be harder simply because we’re another year older.

It’s estimated that between 70 and 85 per cent of seasonal flu-related deaths have occurred in people 65 years and older. Not to mention, the flu can increase the risk for pneumonia, which more people over the age of 65 die from each year than car accidents.

We recently spoke with Dawn Bowdish, the Canada Research Chair on Aging and Immunity, who has spend the last 10 years heading up a lab at McMaster University’s Institute for Research on Aging. She focuses on how changes to our immunity as we age can leave us more susceptible to pneumonia.

TARA LOSINSKI: Why does our immune system dampen with age?
DAWN BOWDISH: My lab’s work says that as we get older, the amount of inflammation in our blood creeps up, and that impairs a lot of our immune cells. There’s other data saying that some of the viruses we’re exposed to over our life course changes or remodels our immune system. So we don’t have a clear answer about why it happens but we know it does happen.

Many groups, including my own, are very interested in finding new treatments or therapies that work within the context of the aging immune system. For example, my lab uses aged mice instead of young mice. We find that some of the things that work in young mice don’t work in old mice – and vice versa. You have to remember there’s a lot going on – our physiology changes, our immune system changes, our metabolism changes – and all these things impact our ability to fight infections.

TL: So is that what makes us more susceptible to pneumonia?
DB: Our preconception is we just don’t respond [as well] to the bacteria that causes pneumonia. But as we age, we have more and more inflammation in our blood and in our tissues and in our lungs. That seems to impair the way our immune cells are made. And so instead of being less responsive when they see the bacteria, we make even more inflammation, and that can cause people to have a lot of fluid in their lungs. So that’s what kills us when we have pneumonia, the fluid in our lungs.

This increase in inflammation as we get older is also probably one of the reasons that other inflammatory conditions get worse after pneumonia because it bumps up all this inflammation.

TL: What conditions can pneumonia exacerbate?
DB: There’s a strong link to having cardiovascular events after having pneumonia: heart attacks and heart disease.

And, I want to make this clear, it’s not a pneumonia that you can deal with outside of the hospital but if you have pneumonia that requires you to go to the hospital. the risk of dementia is very much higher in the next few years. In fact, hospitalization with pneumonia is more closely associated with dementia than any other hospitalization.

And sometimes older adults who end up in the hospital have what we call “catastrophic disability.” They came into the hospital reasonably healthy and active but, by the time they leave, they’re less able to do the activities of daily living. Because pneumonia is such an intense event that they start losing muscle mass – it makes them so sick, and it’s really hard to recover from that.

TL: How do we get pneumonia? Does the flu turn into pneumonia?
DB: The most common kinds for older adults is what we call post-influenza pneumonia. It may start off as being something you can deal with, and then the pneumonia bacteria just take advantage really. They see that you’re compromised and take advantage. So this is why we say get your flu shot and pneumonia vaccine because often times if you survive the influenza, you’re still very vulnerable – and that’s often what kills people.

There’s also what we call community-acquired pneumonia, which is not necessary associated with influenza but usually a bacterial infection in the lungs.

TL: So avoid the flu! And when do we get the adult pneumonia vaccine?
DB: First, it’s important to get the flu shot every year because it changes every year. The pneumonia vaccine is slightly different. It’s imperfect in that it doesn’t capture every single bacteria that causes pneumonia but it does work against the one that is most common in adults. It comes in two different flavours. The recommendations right now is that you have one pneumococcal conjugate vaccine (PCV) first and then, about six months later, you have the pneumococcal polysaccharide vaccine (PPV). So that’s recommended for everyone over 65 or for those who have other conditions that would make them more venerable.

I’ll also say one of the best things to do is make sure your kids are vaccinated as well. There’s this thing called the “Christmas spike” where when grandparents and grandkids get together over the holidays, there’s a spike. And it’s been seen that some reduction in older adults is because we’re getting kids vaccinated.

TL: What do you say to skepticism about vaccines?
DB: People are skeptical because they think they’re linked to harmful side effects or because they think they don’t need them. Older adults generally aren’t as worried about them being harmful as they may remember a time when vaccine-preventable diseases like polio or whooping cough ruined lives. The benefits of vaccination have always outweighed the side effects but, for those think vaccination might be harmful, I’d suggest talking to your doctor or looking at sources like the Public Health Agency of Canada or the National Advisory Committee on Immunization.

For those who don’t think that they need to be vaccinated, I’d ask them to remember that vaccines work best when we are all vaccinated. Even if you don’t get sick yourself, you might give the infection to someone who is vulnerable such as cancer patients, older or frailer adults or those with complicated medical conditions. And just because you didn’t get sick last year doesn’t mean you won’t this year.

TL: Are there side effects from the pneumonia vaccine?
DB: Sometimes people say, “I got sick from the vaccine.” This is because your immune response is similar to when you actually get sick. A small fraction of adults over 50 may get a sore arm, aches and pains and even a fever but, rest assured, that is just your immune system doing its job. Your doctor or pharmacist will ask you to wait around for 15 minutes after your vaccination to make sure you don’t have an allergic response, but these are exceedingly rare.

TL: Let’s talk about inflammation. Why does it increase as we age?
DB: In my lab, we look at how the microbes that live on and in us – and especially in our gut – change with age. And how that causes the gut to become leaky and allow little bits of bacteria in your blood stream, which causes the immune system to become inflamed.

Other researchers have found that all of us have chronic infections that our immune system has to keep under control over the course of our life – and that causes a little bit of inflammation.

A really high-fat, low-fibre diet tends to be associated with having inflammation because that’s very stressful for our gut microbes physiology to deal with. Some people also seem to be a little bit more genetically predisposed and others less so. So there’s probably multiple factors.

TL: Why is it that colds and flus, etc., spike in winter?
DB: There’s a couple different reasons. Especially because we’re indoors – but even if we’re outdoors – it’s really dry, which makes our mucus a little bit thinner. Mucus in our nose and in our throat is one of the ways our body keeps microbes off our cells – it gives like a little cushion. So now we don’t have as much, so those microbes can get into contact with the cells and get into the body a little bit easier.

And then also in Canada, there’s some belief that we are not good at getting our vitamin D. We’re not outside getting that vitamin that our immune system really needs. And we tend to spend a higher proportion of time indoors and in contact with other people. So those factors together seem to be what does it.

TL: Would you recommend vitamin D supplements? And would using a humidifier help?
DB: I would say talk to your doctor. There’s a little bit of controversy because a lot of people find that even if they do supplement, they don’t get the levels quite as high as they need. But vitamin D is one of those ones where it looks like the data is reliably coming back and saying it’s good for multiple aspects of health.

Some people find humidifiers really helpful. I don’t know that there are any super well-controlled studies saying humidifying helps, but certainly anecdotally a lot of people feel a lot better.

TL: What can we do to improve immune health and reduce inflammation?
DB: The best data is the data no one wants to hear: it’s eat a Mediterranean-type diet and exercise. Because those are ways of naturally keeping your inflammation down and lead to a long, healthy life. I know, everyone wants a pill! We all want it to be easy, but the truth is diet and exercise are really the best advice.

It turns out that the food that’s good for you is also good for your gut microbes. So lots of fibre, not so much processed food, not too high-fat a diet, and fish and nuts are really good.

And exercise is nature’s anti-inflammatory. A little bit of cardio [and] a little bit of weight-bearing exercise – that helps you build up the muscles that you need in reserve if you do get a serious infection like pneumonia.