I do not have any information on the change itself, but neither does that claim in Wikipedia.
However, I would refer you to the discussion page of lentil's and read over the community's discussion regarding the article's nutrition claims generally. They are not pleased with many of the claims, and have been active in moderating it. Also of note, the claim has no citation.
Upon my reading, I would not take for granted that the minor act of sprouting in water changes nutritional value substantially, especially as compared to deep-frying them or other processes.
That said, you might refer to the general sprouting article:
These nutrients are essential for human health. To clarify, the nutritional changes upon germination & sprouting have been summarized below. Chavan and Kadam (1989) concluded that - “The desirable nutritional changes that occur during sprouting are mainly due to the breakdown of complex compounds into a more simple form, transformation into essential constituents and breakdown of nutritionally undesirable constituents.”
It goes on to explain that, according to studies done by Chavan & Kadam (1989), Cuddeford (1989) and Shippard (2005), changes during the sprouting process result in:
- Increases in protein quality
- Increases in crude fiber content
- Increases in essential fatty acids
- Increases in vitamin content
The article cites a claim from the Shipard (2005) study: "“When seeds are sprouted, minerals chelate or merge with protein, in a way that increases their function.”
For raw, harder, and bulkier nuts like Almonds try a slightly lower temperature, say 180°C (350°F), and for a longer time
For re-roasting previously roasted nuts use a microwave oven (I know...). Same recipe, but just a few minutes on high. Watch them the first few times until you find the magic time limit before they start to burn
Commercially more and more people are using continuous microwave roasting machines, so using the microwave at home is so bad...
Personally, I like nuts aged in their shells before roasting
Best Answer
Discussion of the long-term health effects would be little more than speculation; however, there is a specific nutritional claim which can be tested, and has been tested in the commercial food-processing setting.
See: Formation of Lipid Oxidation and Isomerization Products during Processing of Nuts and Sesame Seeds:
You'd have to read the whole study for a detailed analysis of how roasting affects the lipid oxidation products, which are the same products seen in rancid or overheated fats, but there is going to be some effect.
This is really more of an issue in a food plant because they use big machines designed to roast huge quantities of nuts (we're talking 200 kg/h for a low-end, $5000 gas-fired machine). The heat characteristics of one of these machines is going to be completely different from the comparatively slow roasting of a tiny quantity of nuts in a home oven, so don't panic.
To be any more specific, you'd have to specify the kind of nut. The oils from different nuts peroxidize at different temperatures; some unrefined nut oils start to smoke at around 160° C / 320° F (peanut/walnut), others go well into the 200° C / 400° F range (e.g. almonds). In any case, it's very rare that you'd actually be heating the nuts up to these temperatures unless you left them roasting too long, and they'd smell very burnt at that point.
Just don't eat hundreds of pounds of roasted nuts every month, and don't burn them when you roast them, and you'll be fine.