@gc

In their summary of the delopment of their guideline nitrate limit for drinking water, WHO note that there is a strong evidence that having an existing gastrointestinal illness increases the risk of suffering from blue baby syndrome. So you are likely on the right lines.

Nov 13, 2017 at 10:51 PM | DaveS

Thank you. The obvious question - have cultures of gut bacteria been tried in blue baby syndrome cases, (or piglets or cows with nitrate poisoning?) or is it too late as the haemoglobin damage has already occurred?

"Such as, what are the predominant dietary sources of nitrate and nitrite? Funnily enough, mainly leafy green vegetables and cured meats, such as are a large part of a "Mediterranean diet" that fosters low morbidity/mortality from Ischemic Reperfusion Injury."

Nov 13, 2017 at 7:43 PM | michael hart

Was nitrite the reason for the bacon/cured meats health concern recently?

Does cooking green veg have any effect on nitrate once it reaches the stomach?

GC, I'm not sure about any of the blue baby or cattle syndromes as that was not a specific part of my research. Ironically, the closer something comes to what I did research, the more cautious I become in my words. I don't know if others experience the same thing.

The bottom line is that most studies are inadequate, if only because of insufficient numbers in any trial, and that depends on money in many, but not all, cases. I have to feel a bit sorry for "Big-Pharma" when a statistically observed toxicity problem only becomes apparent once it is tested on a large fraction of the population. How else could they have found that out any other way?[*]

[*The most expensive failures occur in late-stage clinical trials due to idiosyncratic toxicity, because it's close to the top of the development pyramid. There are people working on that, or rather, ways round it. But it's not easy or quick to describe here.]

..and no, cooking greens will have not much effect on nitrates contained therein. But if you boil them for a long time and throw away the water then you may reduce your intake, and your intake of lots of other vitamins.
Nitrates themselves are thermally very stable. (Which is one reason why they are beloved by explosives and fireworks manufacturers. You don't want the product going off either too early, or not at all.)

This also relates to a classic vitamin case study. Vitamin B3 deficiency causes Pellagra. It was found that poor people in the Southern US who suffered from it exhibited a racial bias, in terms of disease incidence. The textbook explanation is that the white families threw out the water from their boiled corn, whereas the black families drank it and hence actually suffered less disease incidence than their white compatriots. An unusual and unexpected turn of events, given the time and the place.

michael hart, thank you for the updates.

As a country bumpkin, I did bits of the nitrate "practical" before I was taught any science or knew what a nitrate was. I have had to do some work in relation to water purification and filtering, and nitrate in water is readily removed by botany.

The ability of some gut bacteria to convert nitrate to nitrite was new to me, but does explain why consuming water rich in nitrate COULD be a problem.

The reason I asked about boiling veg, was in relation to oxalic acid, the toxin present in many, including beans but especially rhubarb leaves. Oxalic acid is the active ingredient in many cleaning products used to remove rust stains from toilets and fibreglass boats. It is magic stuff, capable of turning red clothing white, and white skin red!