Is it really possible to "build up your immune system"

Well you can damage you immune system by a poor lifestyle, so I suspect you can boost it by looking after yourself.
Don't forget your vitamin D supplements, and don't mess with your body clock and sleep patterns. That really screws up your immune system. As I keep telling OH to no avail .
You do need the right genes but that is mostly out of your control.

Interesting article in the Conversation
theconversation.com/what-supplements-do-scientists-use-and-why-87954?utm_medium=email&utm_campaign=Latest%20from%20The%20Conversation%20for%20January%2012%202018%20-%2092087820&utm_content=Latest%20from%20The%20Conversation%20for%20January%2012%202018%20-%2092087820+CID_46c833c2e886493217c9faae7ea7fa61&utm_source=campaign_monitor_uk&utm_term=What%20supplements%20do%20scientists%20use%20and%20why

I buy these Vitamin D3 (you need the 3) off here
m.pipingrock.com/vitamin-d/high-potency-vitamin-d3-5000-iu-1613
They are super strength plus they come in a bottle not a fiddly blister pack.

Thanks for your link janeainsworth. I'm inclined to go with the last guy (prof of genetic epidemiology) who says no good evidence in properly conducted trials that taking supplements are beneficial and can even be harmful in some cases. I was thinking of taking VitD during winter but will have to do a bit more research.

Lazigirl I think most people, scientists included, agree about the need for supplementing vitamin D in the winter.
The other thing is that everyone is different. As we get older we perhaps are less efficient at absorbing through our gut, so vitamins and minerals become less available.
You might be interested in this site
James Wong is an ethnobotanist & I heard him speak a few months ago at the Chelsea Physic Garden. His talk was fascinating - debunking popular myths about food and advising about how you can get more out of the vegetables you do eat.
He bounced into the room 20 minutes late and opened his lecture by telling us that if you leave supermarket mushrooms on the windowsill for 2 hours, their vitamin D content increases by 5 times. Who knew?
He is on BBC2 with Michael Mosley in February and this is one food programme I’ll be watching with interest.

Yes, I did know [smug] emoticon, however, it is something that I always forget to do. Then, of course, you have to to remember to eat them.
I know only because I saw James Wong on the tv a while ago when he explained that!

Whoops Jane your link didn't work! From what I have researched there has been a huge increase in testing for VitD levels, but although they have been found to be low in certain groups there is no strong evidence that supplementing with VitD actually makes any difference to adverse health outcomes ie fractures, vascular disease etc. But there is a large double blind long term trial taking place at the moment. Interesting about the mushrooms.

www.jameswong.co.uk/home/4587743476
Try that one lazigirl
That’s interesting - I can see that just because someone may have low levels of VitD according to some arbitrary recommendation, they might not necessarily experience illness as a result.

Thanks jane this one works!

Have re read the above comments where i reccomended vit d. It doesnt work. My cold lasted about 2 weeks then i had flu then after a week off work i went back last week only to find ive got a chest infection. Nothing works. Its just chance. I would however like to meet the so called health professionals who say stay at home to avoid spreading germs. As im in my 6th week of illness how can i not go shopping, go to doctors and go to work when i can struggle to get there. Its all a lot of tosh you just cant stay in when you live alone. Sorry i needed a grumble as im so fed up

Oh dear ethel, I hope you feel better soon.
Stay home is an ideal solution in an ideal world but it isn't possible because we don't live in an ideal world.

I have heard that probiotics are good to help to build up the immune system, perhaps a course of those little drinks such as Yakult (or a couple of different ones each day) could help. Homemade soups to boost your input of veg could perhaps help too.
Some people swear by Vitamin C and zinc tablets (fairly cheap too).