question about nightshades...I'm confused.

[draperygoddess]

I have been reading up on nightshades, and there seem to be two different schools of thought on them. One says that the reaction we have to them is due to the toxin they produce. This would indicate that if you're intolerant of one, you would most certainly be intolerant of all of them, since it's the same toxin. But then I read other articles claiming it's the protein we react to, which I suppose could be different from one food to another. I'm interested to know because I have had some violent reactions to potatoes lately, but don't seem to be reacting to, say, tomato sauce. Does this mean I'm only sensitive to potatoes, or that sooner or later I will also react to other nightshades? I was also surprised to read that potatoes are the nightshade least likely to produce a reaction. For the past few months I've been trying to figure out why I was reacting to GF Ora-Ida potatoes, GF potato chips, etc. I figured at first it was the oil they were cooked in, or some other ingredient. The past few times, which were much more noticeable reactions, have been just a baked or boiled potato, no funky oils or additives. I can only conclude it's the potatoes themselves, but this seems odd, since I've been eating other nightshades with no difficulty. I also haven't been eating the skin of my baked potatoes, and isn't that where most of the toxins are?

Any light shed would be appreciated!

[sarkin]

Cynthia,

It's definitely possible to react to some foods in a family, and not to others - sometimes much more closely related foods than tomatoes and potatoes... and in the case of those two, we are also eating a different part of the plant (the fruit, vs. the tuber), which I believe also makes a very big difference.

The solanines in nightshades are definitely problematic toxins, even for "normal" people (if there truly are any of those). The leaves, for example, and the green spots on potatoes, upset almost everyone's digestion. And some fruits in the Solanaceae contain it as well (which is why everyone thought tomatoes were so scary).

I believe it's wise to consider that we *might* have problems with other foods in a certain family, when we know for sure that one is causing trouble. But if you think you can eat tomatoes, you are quite possibly right. You've been honing your food-detective skills for a while now, and it's a different plant part. Potatoes may be the most *likely* to be tolerated, or the least likely to offend, but that's just a statistical assessment, and none of us is a statistic. (Fortunately!)

Similarly, some of us can tolerate no legumes at all, where others need only to avoid soy.

[tex]

Cynthia,

Without getting into detailed differences, the toxins in nightshades that you refer to are alkaloids, but various nightshades contain varying amounts of different types of alkaloids. With potatoes, for example, the primary problem is solanine, which is found primarily in the stems and leaves, but which can also show up in the tubers, (the part we eat), especially if part of the tuber is above ground while growing, so that it is exposed to the sun during some part of the day. Exposure to sunlight, (ultraviolet light, actually), activates a chemical process that creates solanine. Normally, the solanine is concentrated in the skin, (peel), of the potato, and it will usually be marked by a green color of the skin. If the process takes place over a long period of time, though, sometimes the tissue beneath the peel will also be contaminated with solanine. So never eat any potato peels that are green. In fact, it's usually best to throw that whole potato away.

That said, I doubt that solanine causes any MC reactions, but I don't know that for a fact, so we have to assume that it might be possible. If that were true, though, potatoes that showed no signs of green color shouldn't cause any problems, so that suggests that we are reacting to something other than solanine. The problem may indeed be connected with the protein, because potatoes have a much higher protein content than other roots and tubers. In fact potato protein content is in the same range as most grains, so clearly, it might cause a problem, if it happens to contain a peptide that we react to, or one that mimics one of the main gliadin or glutenin peptides in wheat.

Tex

P. S. The green color in contaminated potatoes is not due to the solanine content - it's due to chlorophyll. Chlorophyll is also created in the skin as a result of exposure to sunlight, but it's a different chemical process, unrelated to the generation of solanine. There's no guarantee that green potatoes contain solanine, and normal-appearing potatoes do not, but normally, if the potato tuber is exposed to the correct wavelengths of light, both cholorophyll and solanine will be formed in the skin, so that's why the color is a reasonably reliable marker of solanine content.

[draperygoddess]

Thanks, Sara and Tex! I will be watching tomatoes and peppers verrrryy carefully, but so far, so good! And Sara, I hadn't thought about the fact that the tomato is the fruit of the plant and the potato is the tuber (don't know why it didn't occur to me). Maybe the concentration is different. Whatever the case, they definitely don't like me anymore.

[sarkin]

I think it can even be totally different chemical components, not just different concentrations. Plants "do" different things with their roots/tubers than they do with their fruits. (I was nervous about lemongrass, which is related to grains - many of which are related, come to think of it, and you can eat rice & corn... anyway, lots of people reported having no trouble with lemongrass.)

(I am sorry, though, about the potatoes, and btw excellent job figuring that out. I think it's harder to determine that a really useful food is off the menu, because the mind rebels just a little.)

[MBombardier]

Cynthia, I suspect that your reaction to potatoes is different from a general nightshade problem. People who avoid nightshades do it by and large because of arthritis or psoriasis/eczema issues. Prior to going GF, I avoided nightshades because the next day my knees would be so sore that I needed to walk downstairs backwards, and I would heat up a rice bag to lay on them for some relief. Also, I would get eczema on my lips to the point that my lips would swell and throb, and after the nightshade processed through my GI system, intense itching at the other end. I also would get a rash on my hands with small red bumps that itched badly and would leak lymph when I scratched them.

I went GF September 2010, and in the last few months I have been able to eat nightshades from time to time. Tomatoes, especially, are less troublesome. I can actually eat spaghetti sauce with no problem if I take a day or two between servings. Potatoes are still a problem, if I eat them more than one or two days in a row, but the reaction is significantly less.

So FWIW, I think that you may well be reacting to something else in the potato other than its nightshade characteristic.

[draperygoddess]

Marliss,

Hmmm...so this may fall more into the "protein" category than the "alkaloid" category? That would explain why I'm not noticing a problem with other nightshades. I definitely don't have any of the symptoms you mentioned. Thanks for the input!