INTRODUCTION TO OXALATES
Oxalates are another type of so-called 'anti-nutrients', similar but different to the lectins I wrote about a couple of weeks ago. These substances are only 'so-called' anti-nutrients rather than full-blown and complete and utter anti-nutrients because they do actually also serve a purpose, both within a human digestive system and in their own right. Our livers even product oxalates, so they most definitely serve a purpose in our bodies. Science has not worked out what that is yet though - they suggest it is to do with anti-oxidants and anti-inflammatories.
Oxalates are also known as oxalic acid. Although if we're being precise with chemical terms, the oxalate is formed when the oxalic acid combines with a mineral like potassium, calcium etc, to form a salt. These salts are crystal like and can contribute towards the formation of kidney stones.
Compounds such as oxalates (and phytic acids, or phytates) serve a valuable purpose in the plants in which they occur. They protect the plant from predators - either by creating an unpleasant taste, or an unpleasant digestive effect. Thus the keen predator is dissuaded from visiting that particular plant again to repeat the unpleasant experience.
Oxalate are in most plants that we consume and for most of us they have minimal impact. There are groups of people who are more at risk however. If you have a history of kidney stones or kidney disease, genetic metabolic conditions affecting the kidneys, conditions affecting gastrointestinal absorption, or follow a restricted diet , then you may need to ensure your oxalate consumption is minimised.
The oxalates in nuts vary considerably depending on the nut. And, crucially, just like with phytates, the soaking part of the activation process does reduce the amount of oxalates in the nuts.
Low oxalate nuts and seeds include: Macadamias; Pecans; Pistachios; Walnuts; Hemp seeds; Pumpkin seeds; Sunflower seeds.
So unless you are in a high risk group like those mentioned above, there is no need to be overly concerned about the presence of oxalates in your food. And if you are in one of the higher risk groups, make sure to stick to the low oxalate nuts and seeds, and always go with activated ones!
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