>I find it interesting that the two different recent posts have such >different content for sea vegetables.; one lists laver with 2 vs 378 mg >of magnesium; the other says 121 vs 900 mg in kelp; both are supposed to >be for 100 grams. I wonder why it is such an obscure piece of >information with such a variance. I emphasize that the values I gave for the magnesium content of seaweed refers to non-dried seaweed. Laver contains 85% water, so dry laver would contain 2/(100-85)*100=13 mg magnesium per 100 grams. For kelp, it would be 121/(100-81.58)*100=657 mg Now, that's still very different from the values given by Main Coast Sea Vegs Perhaps it's due to the amount of sea salt (dried seaweed contains some crystallized salt). The Mg content of unrefined sea salt is variable, but Celtic sea salt contains about 1% Mg. See http://www.healthfree.com/celtic/seasalt1.htm and more particularly http://www.healthfree.com/celtic/celtsalt4.htm Lynton: >But heat doesn't destroy magnesium. Perhaps its the bio-availability of it >that's destroyed? If so, how do they know? The data I gave, from the USDA database, have been determined by the following method: "Calcium, iron, magnesium, zinc, copper, and manganese were determined by atomic absorption and plasma emission spectrophotometry" "Analytical mineral values represent the total amount of the nutrient present in the edible portion of the food, including any added to the product in preparation for the retail market. The values do not necessarily represent the amounts of the mineral elements available to the body." Thus, some foods might seem to have a high Mg content, but in reality that magnesium could be poorly available. It is known, for instance that phytates bind to magnesium, zinc, perhaps iron. Grains and seeds contain phytates, but the process of soaking usually eliminates most of the phytates. Oxalates (present in rhubarb and spinach) decrease calcium bioavailability. Fiber can also decrease absorption of various minerals. On the other hand, ascorbic acid enhances iron absorption, calcium in the presence of phytic acid increases zinc absorption (by chelation process, etc.). Availability depends on numerous factors. Now, why roasted sunflower has less magnesium than raw sunflower, I really don't understand why. Minerals are normally indestructible [they are usually roasted with the hulls; is it important, i.e. can minerals be released and deposit in the hulls??] Best wishes, Jean-Louis [log in to unmask]