Acidic and Base Foods (And Onions) and B-12

Answered on August 19, 2014
Created December 31, 2011 at 8:21 AM

I know our stomach acid has a ph of around 3 but adding a significant amount of more acid could be bad. What effect is possible from adding a serving of onion and other acidic foods? What is the ph of cooked onion and why is it that what I have been reading says onion is a great alkaline food but it is acidic? And also, that cooking food makes it acidic? I know making it alkaline has something to do with some reaction with our body but as a reaction directly to B-12, it could be bad.

I have heard information about how there is a concern that a significant acidic or base environment can destroy B-12 and that there was all this concern that Vitamin C supplements were destroying B-12 because they contained ascorbic acid. All of the studies I have read so far tested only 2 grams at the most and said there was no effect but what would the effect of adding a quarter cup or more of onion to your dish or soup be? Anyone who has any advice or who has tried to help would be greatly appreciated.



on January 01, 2012
at 03:55 AM

LOL I understand what you are saying, I was just wondering if anyone has any information, and I am just talking about the claims. I am sure a half cup or more of cooked onions won't effect it much but is there a possibility that adding some raw onion to a soup, with meat in it to cook the onion, could effect the B-12?



on December 31, 2011
at 05:05 PM

You've heard a lot of things, any links to these claims?

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2 Answers



on December 31, 2011
at 02:11 PM

Our bodies aren't helpless. They don't allow overacidification of our guts to take place, and buffer the stomach acid with bicarbonate.

Just a quick word on pH. pH is based on a log scale of free proton (acid) concentration. Thus 1 unit of pH difference is a factor of 10 difference in actual concentration. Our stomachs are in the ballpark of pH 2. If you drank straight vinegar (pH of approx. 2.5), you're still diluting the acid in your stomach. As for ascorbic acid (vitamin C), it's pKa is 4.1, which makes it a fairly weak acid (albeit stronger than vinegar). Concentration matters as well as actual amount. 2 grams of vitamin C is not all that much acid, when compared to the amount of acid in your stomach. The amount of natural acids in food is even lower.



on December 31, 2011
at 02:00 PM

Unless you're chugging vinegar by the cup, I wouldn't worry about getting heartburn. If you hear certain foods make your blood acidic or alkaline, you're hearing BS, not science.

There is a similar question to this one here: http://www.marksdailyapple.com/forum/thread45243.html

A quick google revealed this paper:

"In conclusion, it is highly unlikely megadoses of vitamin C will destroy all cobalamins in the serum and the body stores of healthy subjects. However large doses of Vitamin C may precipitate a Vitamin B12 deficiency in a few patients suffering from one or more errors in cobalamin metabolism."

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