[ryan001]

Why does eating fresh apples cause nausea in some people? Is there a chemical or combination of them that cause this? The exception, for me, are mcintosh apples. For other varieties, I can eat about 1/3 of an apple before experiencing mild nausea (no vomiting) accompanied by a feeling of hunger and jitteriness. I see that others online report the same symptoms.

I’ve done a few hours of online research, but have not found an answer. There are plenty of forums in which sufferers share their woes, but no reasons. I wonder if anyone here knows the answer, or has some advice for searching. So far, I’ve taken two tactics:

1. Look for the abundance of nausea-inducing chemicals in apples. I’ve had to do this backwards (look up biological effects of some common apple components) since I do not have an intuition about what chemicals will cause the symptoms. Should I be looking at esters, carbonyls, aldehydes?

2. Look for differences between mcintosh and other apples. I have not been able to find good data on this beyond basic sugar content, though I suspect it exists in the more expensive literature. I don’t want to pay $50 for an article that I’m not sure has the data I need yet. I’ve also tried to note which chemicals vary among varieties figuring that I could try to find data on that chemical for mcintosh. Also, the mcintosh exception may be more complicated than just a variety that is low in some chemical. For one thing, they tend to be smaller apples, so it may just be a dosage effect. Also, they don’t store well, so they tend to be sold fresh. Thus, other apples may be developing the nauseating effect after months of storage through biological or chemical action.

References:

This paper on the Phenolic composition of apples (including mcintosh) looks like it may be pertinent, but I can only see the first page. They are comparing juicing methods, but the data might still be interesting.
http://pubs.acs.org/doi/abs/10.1021/jf00097a031

White measured the composition of the volatile fraction from a mixed apple juice:
www.honey.com/white/pdf/white12-composition-of-a-volatile.pdf

Markowski et al measured apple juice from some varieties. There is some variation in sorbitol, which I think causes digestive problems in large doses.
www.jhortscib.com/isafruit/isa_pp068_074.pdf

Young et al did mass spec on the volatile fraction from Royal Gala apples
2010.igem.org/wiki/images/1/15/リンゴ元.pdf

GLC volatile fraction analysis of mcintosh apples by Sapens
ucce.ucdavis.edu/files/datastore/234-1745.pdf

This herbal website lists some compounds in apples with “known biological activity”. I’m not sure how useful this is.
http://www.herballegacy.com/Lovett-Brown_Chemical.html

[fledarmus]

You might want to look at this...

http://en.wikipedia.org/wiki/Oral_allergy_syndrome

[ryan001]

You might want to look at this...

http://en.wikipedia.org/wiki/Oral_allergy_syndrome

Good point. Oral allergies may be pertinent, though the symptoms listed seem tend to be topical, particularly itchy mouth. I, and the others I've seen online do not have those symptoms. I wonder if the mechanisms are similar or not. There have been recent studies showing that people in northern Europe who go to the hospital for food allergies (often anaphylaxis), tend to do so for raw apples. In southern Europe, it is for uncooked or cooked apple skins. In the US, peanuts. New Scientist had an article about this (I think it's pay only - I subscribe). If this is an allergy, then causality could become difficult. For instance, the New Scientist article reports that shrimp allergies are linked to dust mites. That is, reaction to one thing can sensitize a person to some, quite unrelated, other thing. I could try taking a strong antihistamine before eating an apple to see if it has an effect. That could shed light on allergy as a mechanism. I'll give it a try this week.

[Fluorine]

I can't eat apples myself without getting disgusted and nauseous - not sure if it's the same thing though. Anyway this article might be of help to you.

http://www.ncbi.nlm.nih.gov/pubmed/9802379 (Bet v 1, the major birch pollen allergen, and Mal d 1, the major apple allergen, cross-react at the level of allergen-specific T helper cells.)

[ryan001]

That article describes one of the best known allergy links: birch pollen and foods (especially apples). Those are IgE-mediated (histamine) allergies with major symptoms like topical itchiness and swelling.

I think our apple intolerance is mediated by some other reaction. One example is hereditary fructose intolerance, which has symptoms such as "hunger, nausea, vomiting and abdominal pain".

http://www.medicalinsider.com/foodallergy.html#fructose
http://en.wikipedia.org/wiki/Hereditary_fructose_intolerance#Signs_and_symptoms
 

[rjb]

Ryan,

Out of curiosity, do the same symptoms occur after consumption of apple juice (pasteurised and non-pasteurised) or is this related only to whole apples?

Any issues with Pear, Grape and in particular figs?

[ryan001]

Good question. I sometimes drink a lot of sweet cider, and haven't had a problem. I haven't noticed a reaction with grapes or pears. I'll look for pears this weekend and eat a big one and report back.

[ryan001]

Following up: Pears do not cause a problem, nor does apple cider (sweet pasteurized and fermented are both OK).

[shelly]

Hi, Fellow Sufferers,

I was wondering if anyone else out there became nauseated from eating raw apples, and lo and behold found this forum.  I have no insight into the problem, but they do make me sick, and I eat them anyway.  I just thought I'd pass this along.  My doctor says that I must be eating them too quickly. That is not my sense. 

[Theoden]

link=topic=51002.msg190836#msg190836 date=1316734064]
Good question. I sometimes drink a lot of sweet cider, and haven't had a problem. I haven't noticed a reaction with grapes or pears. I'll look for pears this weekend and eat a big one and report back.
[/quote]
I have found that cooking the apples does away with any nauseous effect. Perhaps the sickening chemical is an organic compound that can be decomposed with heat? [quote author=ryan001

[writer]

That article describes one of the best known allergy links: birch pollen and foods (especially apples). Those are IgE-mediated (histamine) allergies with major symptoms like topical itchiness and swelling.

I think our apple intolerance is mediated by some other reaction. One example is hereditary fructose intolerance, which has symptoms such as "hunger, nausea, vomiting and abdominal pain".

http://www.medicalinsider.com/foodallergy.html#fructose
http://en.wikipedia.org/wiki/Hereditary_fructose_intolerance#Signs_and_symptoms

If you can eat pears without a problem you do not likely have hereditary fructose intolerance. In this genetic disorder you get terrible symptoms after consumption of even minute amounts of fructose from any source, even from sucrose (glucose + fructose).

Regarding you can eat pears, you also do not likely have fructose malabsorption.