However, I it would have to matter if the test was done with vinegar or not. One seldom cooks acidic liquid foods in cast iron. I would not worry about getting a significant amount of iron. The seasoning offers an additional layer of protection which is not leached off unless you cook acidic things, usually liquids. I cook liquids in enamel or poreclain on steel. Cast iron pots have been used for millennia. I feel that they enhance health. They also make you a better cook.
I'm not sure why you are diverting attention to the vinegar each time, and not the iron contamination. The vinegar was just a baseline test substance for each pan type to determine leaching.
And I'm sure most people cooking, cast iron or otherwise, don't realize whether their food is acidic, alkaline, or neutral -- or the chemical changes taking place as it is cooked. In fact, each ingredient in the dish being prepared that is touching the cast iron would have it's own pH association & reaction with the cast iron it contacts, as it leaches into the dish being prepared.
Of course cast iron has been used for millennia, since it was relatively easy and cheap to produce, but I don't think they did any safety studies on it for cooking purposes at the time. Depending on the historical time, and region, the iron leached into their food could have been beneficial -- or a detriment.
Cast iron utensils do enhance your health, but only if you're iron deficient.
I'm not sure how you can emphatically state that they would make you a better cook though.
Several studies confirming the iron contamination of food cooked in iron pots have been reported more recently. Liu et al. investigated the levels of iron in foods cooked in Chinese iron pots and reported two- to five-fold increases in iron content over foods cooked in aluminium, stainless steel and clay pots.
Evidence of iron contamination of food cooked in an iron skillet has been provided for foods typically consumed in the USA, for Chinese foods cooked in a steel wok, and for Indian foods prepared in iron pots. Acidity, moisture content and cooking time increased this iron contamination in each of these studies.
A study comparing Ethiopian foods cooked in iron, aluminium and clay pots, found that there was more crude iron in all foods cooked in iron pots: around twice as much iron in meat and vegetables, and 1.5 times as much iron in legumes than in food cooked in the other two types of pots.
Source: http://direct.bl.uk/...7528900&ETOC=RN
And "seasoning" your cast iron is good for the first couple of uses only:
That iron dissolves from iron utensils better when foods are acidic as in this study is well known.
The effect of continued use of the same iron utensils for cooking 50 times on iron content of two foods is studied. Although iron values for the first two times the utensil was used were lower than those for the other times, iron content of the food was similar through the 50 times. The initial seasoning of the iron utensils apparently affected the amount of iron taken up by the food during cooking the first two times.
Our study indicated iron cookware used on a continuing basis increased iron content of food and thus the intake of iron at least as much as new iron cookware.
Source: http://onlinelibrary...5331.x/abstract
And here's a study comparing hamburger patties and their own lab-made applesauce (from fresh apples) on glass and cast iron pans (oh, note that no vinegar was used here either):
When measuring dietary iron, the iron obtained from cooking in iron utensils should be considered. Cooking food in iron utensils (Brittin and Nossarnan 1986a; Borigato and Martinez 1992; Kollipara and Brittin 1996), steel woks (Zhou and Brittin 1994), or stainless steel utensils (Park and Brittin 1997) increases its iron content, Iron added to food by cooking in iron utensils is bioavailable (Mistry et al. 1988). Used iron cookware increases iron in food as much as new iron cookware does (Cheng and Brittin 1991).
Changes in sensory characteristics of food may occur when food is cooked in iron utensils due to increased iron content. We have found no published research on the effect of cooking food in iron utensils on sensory quality or acceptability of food. Our preliminary investigation indicated significant differences in taste, flavor, and color of applesauce cooked in iron versus glass utensils. The purpose of this study was to determine whether cooking food in iron utensils affects its iron content, sensory quality, and consumer acceptance.
Hamburger patties cooked in iron and in glass did not differ in moisture content. Iron content was higher (P < 0.05) in patties cooked in iron than cooked in glass. Because moisture content did not differ between patties cooked in the two different utensils, the difference in iron content of food cooked in iron and that cooked in glass was not due to difference in moisture. Although hamburger cooked in glass contained significantly more iron than raw hamburger, this difference is due to their different moisture content; calculation of iron content on a dry weight basis showed 4.37 and 4.45 mg iron per 100 g dry food, respectively, a 1.8 - .9% difference. Correlation analysis showed no significant (P > 0.05) association between iron content and beef-flavor or off-flavor of hamburger patties.
Raw applesauce had the lowest pH; applesauce cooked in iron had the highest pH. The higher pH of cooked applesauce than raw applesauce may be due to loss of volatile acids during cooking. Iron content of applesauce cooked in iron utensil was the highest (P<0.05) among three treatments, 133 times that of the other two treatments, which did not differ. The pH, moisture, and iron values of hamburger and applesauce are similar to values reported previously (Brittin and Nossaman 1986a; Cheng and Brittin 1991).
Source: http://onlinelibrary...0207.x/abstract
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