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Ep. 63 – Oxalates

A long-time listener to Straight Talk on Health heard a guest on another podcast talk about the dangers of oxalates. According to this person, avoiding eating foods with oxalates cures just about everything. What are oxalates? And is this true? Dr. Chet explores this topic on this edition of Straight Talk on Health

Welcome to Straight Talk on Health. I’m your host Dr. Chet Zelasko. Straight Talk on Health is a joint production with WGVU in Grand Rapids MI. I examine the world of health. Nutrition. Exercise. Diet. Supplementation. If there’s something new, I look at the science behind them, and let you know whether it’s real or not. You can check out other things that I do on my website Drchet.com and sign up for my free emails.

A long-time listener asked me whether they need to be concerned about the oxalates in foods. Evidently, they had watched a podcast with a guest who essentially said that the cause of whatever ails you are oxalates. What are oxalates? More correctly, oxalic acid is a 2-carbon organic compound found in many plants, including leafy greens, vegetables, fruits, cocoa, nuts, and seeds. A property of this common food acid is that it binds to minerals, especially calcium. For those people who are prone to forming stones and crystals in their body, oxalic acid can be enemy number one. But the question about oxalic acid is simple: is it dangerous to everyone?

She is Sally Norton, a health coach and speaker. The most significant claim, as a guest on a podcast, at least in the one that I viewed, was a reduction in joint pain when oxalic acids are removed or reduced in the diet. She talked about her feet and how she could not walk without shoes. By going on a low-oxalic acid diet, she eliminated joint pain as well. That led me to an article she had published in the Journal of Evolution and Health in 2017. At 24 pages with over 160 citations, she appears to have put in the background work. The question is whether her interpretation of the research leads to the same conclusion: oxalic acid is detrimental to the health of almost every person on the planet. Let’s take a look at the article to find out. Specifically, whether joint pain is caused by the over-consumption of oxalic acid from foods.

What foods are we talking about. Green leafy vegetables especially spinach and collard greens, all types of beans, nuts, beets, rhubarb, and tea. Fruit doesn’t escape with raspberries, oranges, grapefruit, canned or dried pineapple, dried figs or prunes, dates, and kiwi on the list. One exotic fruit that makes the list is starfruit.

The reason that oxalic acid is detrimental is that it binds with minerals, especially calcium, to make stones and crystals. That can include kidney stones, gall stones, bladder stones, and the crystals that form in joints to cause gout. Again, throughout the paper, she makes the statement that joint pain is caused by oxalic acid.

I checked at least 25 to 40 papers that were related to claims that the author made to see if they matched. I'll read what the author stated and then give you a synopsis of the research to see if they match.

Let's begin with this quote: A diet with a preponderance of foods containing substantial oxalate has long been known to be dangerous, and sometimes deadly. She cites that rhubarb, star fruit, and sorrel have been used as the proximal cause of death. What she doesn't state is that as it relates to rhubarb, it was the accidental consumption by infants who ate rhubarb leaves that contributed to illness and in at least one case, death. The most important that she does not state is that in every case, these are people with Chronic Kidney Disease. Some were on dialysis. Some were about to begin dialysis. But they all had severe CKD. That's something important to mention because the implication is that everyone would be at risk. If you had undiagnosed CKD, that could be true but that's unlikely in most Westernized medicine countries.

With over a 100 year window of research to choose from, and she did, one could find many cases of over-consumption of just about any food that had health repercussions. But if it’s as common a problem as she states, there should be more than case studies.

She then states “oxalate are a likely contributor to many modern health problems.” She then sites several studies that prove her point. I checked out several of those references. In one study, done in rodents, the objective was to see what would happen in people with gastric bypass surgery and the results extrapolated to humans. The study was a “one off” which means no one has done any further research on humans. In the references that she cites she says that the typical amount of oxalates in our diets can contribute to oxalate accumulation in non-renal tissue. One reference says no such thing, a second reference is talking about infusing oxalate directly into the bloodstream of rodents which has nothing to do with what the rodent or humans ate, and in the final reference, it suggests no such thing and has six human subjects. She hasn't exactly supported her statement that oxalic acid is a likely contributor to modern health problems with the research that she herself cites.

Throughout the article, she consistently referred to joint pain and yet, there were no citations that linked actual intake at levels that Americans typically eat with anything such as arthritis or other forms of joint pain.

While I think she is wrong about the severity of the problem that she claims is the cause of everything that ails us, I do think that there is something there. She uses a citation from one of my favorite researchers on minerals. He did a study that looked at the relationship between oxalic acid and calcium absorption. There were several subjects that appeared to have higher levels of oxalic acid in their blood than others. He used the phrase super absorbers. Undoubtedly, that could be a gene mutation of some sort that has yet to be identified. What it means is that some people may absorb more oxalic acid than others. When you combine genetic factors with some form of pre-existing condition, perhaps diabetes or some form of CKD, they could be at risk if they consume too much oxalic acid. But is it something that we all need to be cautious of as she claims? I don't think so and the lack of a link between joint pain and oxalate intake confirms that. What a high intake of oxalate may mean is undiagnosed CKD or prior kidney damage. The inability to process oxalic acid may make the user at risk when consumed in high levels.

Near the end of the article, she makes another statement that summarizes things very well. The symptoms of oxalate toxicity can be very hard to identify primarily because the patterns vary in idiosyncratic ways from person to person. They are often subtle, typically affect multiple body systems, and often flare up unpredictably and irregularly.

Another way of stating this is “I can’t find it but I know it’s there somewhere.”

The author obviously is passionate about oxalates. But after reviewing the science in her publication and looking up many pertinent references tied to the claims that she makes about the dangers of oxalates, I just don't see the foods that she's identified, as being a danger to the health of the nation.

Having said that, I think that people who have diabetes or pre diabetes, who have any form of liver disease, even though she claims that the liver is not involved in oxalate metabolism, and especially any form of kidney disease, would do well to keep track of their oxalate intake. The problem is not with the food; the problem lies within the individual. It's not a blemish on them nor is it someone who is defective. Rather, as i suggested earlier, it is a combination of genetics, the microbiome, as well as other diseases and conditions other than oxalate poisoning. I’m out of time so until next time, this is Dr. Chet Zelasko saying health is a choice. Choose wisely today and every day.

 Norton, Sally K Lost Seasonality and Overconsumption of Plants: Risking Oxalate Toxicity Journal of Evolution and Health: Volume 2, Issue 3, 2017


Dr. Chet Zelasko is a scientist, speaker, and author. Dr. Chet has a Ph.D. and MA in Exercise Physiology and Health Education from Michigan State University and a BS in Physical Education from Canisius College. He’s certified by the American College of Sports Medicine as a Health and Fitness Specialist, belongs to the American Society of Nutrition, and has conducted research and been published in peer-reviewed journals. You can find him online at drchet.com.
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