According to BBC News, recent research supports the hygiene hypothesis:
Normal bacteria living on the skin trigger a pathway that helps prevent inflammation when we get hurt, the US team discovered. The bugs dampen down overactive immune responses that can cause cuts and grazes to swell, they say.
And other recent research says it’s wrong:
The decades-old “hygiene hypothesis” holds that early exposure to microbes somehow challenges the immune system and strengthens it against allergies. Studies have shown children exposed to bugs by older siblings or attending nursery cut their future allergy risk.
But new work published by the American Thoracic Society casts doubt on this.
The study by Dutch investigators at the Erasmus University found although children in day care got more colds and other infections, they were just as likely as other children to go on to develop asthma or another allergy by the age of eight. The children who went to nursery and who had older siblings had more than quadruple the risk of frequent chest infections and double the risk of wheezing in early life, with no obvious pay off in terms of later protection from allergy.
The original hygiene hypothesis said that exposure to harmful germs (e.g., that cause colds) cuts down on allergy risk. But it’s now clear it’s the exposure to harmless germs (e.g., in dirt) that’s helpful.
Allergies in the UK have tripled in the last 10 years. I believe this is due to greater consumption of food that is germ-free, such as factory food and restaurant food. Shelf-life considerations and food-safety laws, in other words.
Advice given by Allergy UK:
The best advice we can currently give to parents is not to smoke around their children and make sure they have a balanced diet and get plenty of exercise.
Not even close to what I think. My advice is: Feed your kids plenty of fermented food, such as yogurt. I’d bet a lot of money that my advice is better.
Thanks to Mark Griffith.
“My advice is: Feed your kids plenty of fermented food, such as yogurt.”
I think it’s more then that. If you feed kids fermented foods that will propably help, but if you also continue to feed them with such a healthy junk like tons of grains and grain fibre, which will continue to damage their guts, it’s like taking cure together with poison. In this case the poison may be stronger than the cure.
In my case I was eating quite a lot of fermented foods, but it did nothing to my asthma and allergies. Only after I started to eat grain free (paleo style) they went away (after about 9 month since this change) and my digestion improved.
My point: I believe your theory about bacterias is correct (because they protect guts by helping with digestion and by enriching the food), but too simplistic. In case of autoimmune diseases other factors may be stronger then the ingested bacteria – as was my case.
Also, the increase of incidence of allergies may correlate more with current dietary recommendations (grains, fibre) than with bacteria consumption, but here the issue is little fuzzy, because less fermented foods also means more junk carbs and fibre.
It’s an interesting hypothesis, that exposure to harmless bacteria helps the immune system. If it were true, what might explain it? The best I’ve come up with:
(1) Exposure to harmless bacteria is how the immune system calibrates its sensitivity. When almost none are available, the immune system becomes overly sensitive.
(2) Harmless bacteria aren’t merely harmless but a functioning part of the body’s immune system. When there aren’t enough, the immune system breaks down.
(3) Harmless bacteria are a proxy for the absence of pathogens. When harmless bacteria are lacking, the immune system thinks pathogens are abundant and prepares for battle.
Any others?
Cheers,
Tom
Tom, those are great hypotheses.
I find that full-fat yogurt really brings down my allergies, which have been severe all my life. I think it may be the combination of the cultures in the yogurt and anti-inflammatory properties of the butterfat in the yogurt.
Grains alone can hardly be the problem. People 100 years ago used to eat more more grains-often exceeding 1 kg of wheat per day.
But the grains used to be properly prepared, with low-temperature grinding, fresh flour and sufficient soaking
. I think that’s the key
Gian,
I don’t think it’s that simple. I can tolerate soaked or fermented legumes, I do fine on moderate amount of rice, but all other grains are out of question (including some non-grains like buckwheat). Like Seth I like self-experimentation and I did quite a lot of it on myself with grains. Sourdough fermented (3 days) wheat or rye bread made from freshly ground flour will still give me rapid heartbeat for several hours, brainfog and headaches. After a week long experiment I ended with strong diarrhea and a fever.
Before switching to paleo, I had the same symptoms all the time, but I was so used to them that it was not so insufferable. But as a one time experience they are intolerable.
So I don’t agree with simplistic theories like let’s just soak them and everything will be fine. Does not work for me and many others.