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In Reply to: spinach posted by laura dl. on June 11, 2008 at 10:33 am:
The best thing you can do is to not depend on one food for specific nutrients-- eat a variety and eat them both cooked and raw, is my advice. That said, here is some info on spinach and oxalates from World's Healthiest Foods (http://whfoods.com/genpage.php?tname=foodspice&dbid=43 read the whole page for all of the benefits of spinach, which include many powerfuil antioxidants): "For the vast majority of individuals who have not experienced the specific problems described above, oxalate-containing foods should not be a health concern. Under most circumstances, high oxalate foods like spinach can be eaten raw or cooked and incorporated into a weekly or daily meal plan as both baby spinach and mature, large leaf spinach can both make healthy additions to most meal plans. In short, the decision about raw versus cooked or baby versus mature leaf spinach or other oxalate-containing vegetables, for example, should be a matter of personal taste and preference for most individuals." "Spinach and Oxalates Spinach is among a small number of foods that contain measurable amounts of oxalates, naturally-occurring substances found in plants, animals, and human beings. When oxalates become too concentrated in body fluids, they can crystallize and cause health problems. For this reason, individuals with already existing and untreated kidney or gallbladder problems may want to avoid eating spinach. Laboratory studies have shown that oxalates may also interfere with absorption of calcium from the body. Yet, in every peer-reviewed research study we've seen, the ability of oxalates to lower calcium absorption is relatively small and definitely does not outweigh the ability of oxalate-containing foods to contribute calcium to the meal plan. If your digestive tract is healthy, and you do a good job of chewing and relaxing while you enjoy your meals, you will get significant benefits - including absorption of calcium - from calcium-rich foods plant foods that also contain oxalic acid. Ordinarily, a healthcare practitioner would not discourage a person focused on ensuring that they are meeting their calcium requirements from eating these nutrient-rich foods because of their oxalate content. " http://whfoods.com/genpage.php?tname=george&dbid=48 "Can you tell me what oxalates are and in which foods they can be found? Foods that contain oxalates The following are some examples of the most common sources of oxalates, arranged by food group. It is important to note that the leaves of a plant almost always contain higher oxalate levels than the roots, stems, and stalks. * Fruits Oxalates and health Conditions that require strict oxalate restriction There are a few, relatively rare health conditions that require strict oxalate restriction. These conditions include absorptive hypercalciuria type II, enteric hyperoxaluria, and primary hyperoxaluria. Dietary oxalates are usually restricted to 50 milligrams per day under these circumstances. (Please note: these relatively rare health conditions are different than a more common condition called nephrolithiasis in which kidney stones are formed, 80% from calcium and oxalate). What does 50 milligrams of oxalate look like in terms of food? One cup of raw spinach in leaf form (not chopped) weighs about one ounce, and contains about 200 milligrams of oxalate, so 50 milligrams for the day would permit a person to consume only 1/4 cup of raw spinach (and no other oxalate sources could be eaten during the day). Oxalates and kidney stones The formation of kidney stones containing oxalate is an area of controversy in clinical nutrition with respect to dietary restriction of oxalate. About 80% of kidney stones formed by adults in the U.S. are calcium oxalate stones. It is not clear from the research, however, that restriction of dietary oxalate helps prevent formation of calcium oxalate stones in individuals who have previously formed such stones. Since intake of dietary oxalate accounts for only 10-15% of the oxalate that is found in the urine of individuals who form calcium oxalate stones, many researchers believe that dietary restriction cannot significantly reduce risk of stone formation. In addition to the above observation, recent research studies have shown that intake of protein, calcium, and water influence calcium oxalate affect stone formation as much as, or more than intake of oxalate. Finally, some foods that have traditionally been assumed to increase stone formation because of their oxalate content (like black tea) actually appear in more recent research to have a preventive effect. For all of the above reasons, when healthcare providers recommend restriction of dietary oxalates to prevent calcium oxalate stone formation in individuals who have previously formed stones, they often suggest "limiting" or "reducing" oxalate intake rather than setting a specific milligram amount that should not be exceeded. "Reduce as much as can be tolerated" is another way that recommendations are often stated. The effect of cooking on oxalates Cooking has a relatively small impact on the oxalate content of foods. Repeated food chemistry studies have shown no statistically significant lowering of oxalate content following the blanching or boiling of green leafy vegetables. A lowering of oxalate content by about 5-15% is the most you should expect when cooking a high-oxalate food. It does not make sense to overcook oxalate-containing foods in order to reduce their oxalate content. Because many vitamins and minerals are lost from overcooking more quickly than are oxalates, the overcooking of foods (particularly vegetables) will simply result in a far less nutritious diet that is minimally lower in oxalates. "
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