Information about Low-Oxalate Diets
LowOxalate.Info offers a great resource of information on the low oxalate diet and gives the what’s where’s and why’s of the molecules called oxalates.
What is oxalate?
Oxalate is a very simple sort of molecule that links up with calcium and then crystalizes under some conditions, including when it encounters damaged tissues. The crystals formed this way can be quite irritating and painful to tissues where they form, causing or increasing inflammation. These crystals can be especially painful if they lodge themselves in places where they get in the way of the movement of other things through tight places. These physical issues are easy to understand, but there are still many secrets nature has about how oxalates interact with other parts of the metabolism.
Where do oxalates come from?
Oxalates are present in a lot of plants and fruit that we eat and in virtually all seeds and nuts. Ordinarily, the gut won’t absorb much of the oxalate from the diet, and the oxalate will be metabolized by the flora or just leave the body with the stool. Under other conditions, a lot of the dietary oxalate is absorbed. Overabsorption is far more likely to occur when the tight junctions between the cells which line the gut open up and let molecules pass through between the cells in a condition called the “leaky gut” which is similar to a condition in the bladder with open junctions called the “leaky bladder”.
How does this happen and why is it a problem?
When substances move to the blood by going around intestinal cells, they bypass the regulation that is present when these same substances move instead through the cells. When the transport occurs through cells, the cells themselves control the quantity that crosses by regulating the number of transporters that allow that substance into the cell. After the substance crosses the cell, it can leave the cell to join the blood by means of a different set of transporters that are on the blood or “exit” side. With this kind of regulation coming from both sides of the cell, when the body recognizes that you don’t need more of a substance from food, the cell won’t let more of that substance cross through. The body obviously loses that regulation when substances are absorbed through the “leaky” junctions between cells. Oxalates are just one of the substances where this is a problem, but whenever more oxalates are absorbed like this, the result may be high levels of oxalates in blood and urine and in tissues. Scientists call the high levels in urine hyperoxaluria.
Eating food high in oxalates is not the only way to get high oxalates systemically. Our bodies make oxalates on their own, especially when certain enzymes aren’t balanced in their activity. Normally, once oxalates are in the gut, they may encounter particular species of bacteria which will digest them and turn them into something else that isn’t so irritating. This system of microbial digestion may be why the body seems to purposefully route excess oxalate from the rest of the body to the gut. Unfortunately, the very microbes we need to do this digesting of oxalates for us are subject to being killed by antibiotics in common use. Even if there was no exposure to antibiotics, these microbes might not have colonized yet in very young children, for it does not tend to be in breastmilk, but must be picked up from the environment.
Lactobacillus acidophilus is an oxalate-eating species, but when oxalates are in excess, lactobacillus can be killed off. It will be interesting to learn whether this may explain why certain people have great difficulty colonizing lactobacillus acidophilus. Fortunately, a probiotic formulation of a bacteria called oxalobacter formigenes that helps digest oxalates even better than lactobacillus is under development for patients with hyperoxaluria and related conditions.
How do oxalates function in the body?
There is a positive side to oxalates because they help us manage calcium, but the management of oxalates themselves will fall down when cells are low in glutathione and also in oxidative stress. Oxalates add to that oxidative stress.
Plants use oxalates to protect themselves from infection or from being eaten, as these crystals can tear up the mouths of the bugs that eat them, but we haven’t learned nearly enough about the positive side of oxalates in humans. We know a lot of negatives about oxalates, but we are just starting to learn what chemistry will change when both the sulfur and oxalate chemistry are disrupted at the same time.