Do your allergies change every 7 years because your body chemistry changes every 7 years?

A popular theory... but is it fact or fiction?

This whole 'your body chemistry changes every 7 years' thing is something keep hearing time and time again at the moment, with all the reading I've been doing into allergies. The idea, from what I can gather, is that every 7 years your body's cells are completely regenerated. Not all at once obviously. Your body is constantly losing and regenerating cells. The theory is that after every 7 years, every cell has ultimately been replaced, meaning that any tolerances that your body has built up over the last seven years are now gone (your 'body chemistry' has supposedly changed) and this means that you may find yourself developing allergies to things that you were never previously allergic to.

Is there any scientific evidence for it?
This 'fact' gets quoted left right and centre but I have never seen it used on any kind of reputable health website. Whenever it is raised on any such site it is always dismissed as an old wives' tale. Not only do the cells from some parts of your body (your bones for example) take more than 7 years to regenerate, but even if 7 was the magic number, as it's a gradual process I don't see why it would make such a difference, I mean, at any one time lots of your cells would still have anything up to seven years behind them.

So basically I have not come across any evidence that it is anything but an old wives' tale. However, many good medical sources do simply state that at any time in your life you can become allergic to things that you were previously fine with, which I can categorically state is true!

Anecdotal 'evidence'
The only reason that the 7 year body chemistry change myth intrigues me is because my big change in allergies and skin sensitivity happened when I was aged 28 and someone at my work who I was discussing my skin problems with said that she started having psoriasis flare ups really badly when she was about 28. She said it lasted for a few years and then just went away again. Just the other day somebody else mentioned that all their allergies kicked in at age 21.

A self-fulfilling prophecy?
Could it be that people whose allergies kick in at 21 or 28 mention their age as significant because they have already heard the 7 year theory, while those whose allergies kicked in at different ages never mention the age they started (because it doesn't happen to fit in with any theory).

If anybody else has any thoughts or experiences on this 7 year cycle, please do share them. Do you think there is anything in it?
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Post a Comment

  1. I have found that it does seem my allergies have followed the 7 year cycle. When I was younger, I had horrible seasonal allergies, but before highschool they started to get better and I started to have fruit allergies. Those lasted until the middle of college, about 7 years, and have been going away since. I'm not 27 and have almost no food allergies but in college I started to be allergic to animals. We'll see if those start going away any time soon. With me, it just seemed like it would be full force for 7 years, then would go away for 7 years, then be relegated to an afterthought.

  2. Hmm. Interesting. I came across this article looking for a reason why I suddenly developed an allergy to my dog (I've had dogs my whole life) at the age of 42. I had the dog two years then suddenly whenever he came in contact with skin I would get itchy. Wierd. Hoping it goes away as quickly as it showed up.

  3. i turned 42 last summer, i lost my sense of smell completley, became gluten intollerant, hair began graying and falling out, And im having more skin allergies. just last week I cut some shrub branches (no it was not pision ivy, oak, or sumac) and the leaves brushed my skin and I had an inflamed area for several days, I also bought some flipflops for plantars faciatis and the straps broke the tops of my feet out with bumps and itching. i emailed the company who said they were made of neoprene. currently waiting to have some skin allergy testing done

  4. I acquired allergies for the first time at 42

    I new nothing of the 7 year cycle until after i started suffering so your hypothesis is invalid with me

  5. Ever 7 years it's like clockwork. I am 35 now and I just develop eczema. I never had this before and it's a mess. Let's see what happens at 42

  6. How interesting so many of you are saying age 42! Divisible by 7...

  7. I just turned 43 and seriously, my skin problems like eczema and dermatitis began at age 35. Interestingly enough, last year at age 42 my skin allergy triggers have been completely out of control and I just found out I'm allergic to numerous things. Was never allergic to these things before and now all the sudden they're affecting me in a huge way. My life has recently been derailed due to auto-immune skin rashes, rosacea and eczema. Going to try the gaps diet! Wish me luck!

    1. So sorry to hear that Earth Girl - isn't that strange about the years thing? Wishing you the best with your diet xx



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