Book Review of "Toxic Superfoods" by Sally K. Norton, MPH

Finally an up-to-date, research-backed book on oxalates! I’ve heard the author, Sally K. Norton, speak on several occasions and have participated in some of her nutrition groups so when this book was announced, I was very excited! I’m always impressed with her wealth of knowledge and scientific rigor, and my impressions were confirmed reading the book. Oxalate-awareness has been an important puzzle piece in my healing, and I am continuously thirsty for more high quality information on this topic…if you’ve ever scoured the internet to learn about oxalates, it sometimes feels like the wild wild west. There are discrepancies between food lists and inconsistencies between sources. And there hasn’t been a lot of study of oxalates outside of kidney stones and primary hyperoxaluria, but hopefully this book will spawn more research and interest in the topic, as this seems to be affecting more and more people as spinach smoothies and almond milk become almost staples in the “healthy diet.” This book covers what oxalates are, symptoms of overload and how to clear oxalates. It contains excellent resources that I felt I could trust for further study, including the Vulvar Pain Foundation, which I had come across years ago, but just recently connected the dots. I had so many takeaways after reading this (so this is going to be a lengthy list). I used an entire pack of post-it notes to mark pages while I was reading! Here are my favorite takeaways:

• Veggies in the cabbage-family and “true lettuces” are generally low oxalate (contrary to much of the information you find online!), whereas seeds, nuts, beans, whole grains (particularly buckwheat and amaranth families…beets, chard, spinach, quinoa, rhubarb) are high (page 28).

• Evidence is lacking on the protective effects of antioxidants (polyphenols, carotenoids, ascorbate, vitamin E), whereas essential nutrients, such as B1, are essential in preventing cellular oxidation (page 62). It was interesting to get her perspective on antioxidants since there are such divergent opinions out there!

• Fiber feeds good and bad bacteria. Thus, fiber can contribute to overgrowth and inflammation in the colon (page 67). More evidence that fiber is not always better!

• Studies on primary hyperoxaluria (rare genetic disorder) provide information on how high oxalate diets can affect the body….think pain, bone health, joint issues, skin issues…and the list goes on…and on…and on. I was surprised to see some of my quirky symptoms listed in the book that I never would have related to oxalates….like rolling veins during blood draws!...I’m the one swinging my arms, drinking water, wearing a winter hat and coat at the lab! Some of my other symptoms that were specifically mentioned in the book include scleroderma/dermatomyositis (I’ve been diagnosed with undifferentiated connective tissue disease), vulvodynia, osteopenia, raynaud’s, IBS and ehlers-danlos syndrome…to name a few. Given that many of these are quite rare, this did validate some of my suspension of oxalate overload.

• Excretion of oxalates is through the kidneys, colon, skin and saliva glands (ever wake up with crusties in your eyes?...). She distinguishes this as different from toxin removal through the liver.

• The author finds that very low carb diets (strict keto) can be a shot in the foot as liver cells make more oxalate when deprived of sugar. She suggests 75 to 150 grams of carbs (page 113). This was fascinating to a lady who was in ketosis for over a year to deal with inflammation!

• Gut permeability, as well as food combinations (oxalates with gut irritants and lack of calcium or high water content) play into how much oxalate will be absorbed (page 115)….hmm, maybe skip the smoothie!

• Only one-third of healthy Americans have Oxalobacter formigenes populations (good guys who encourage excretion of oxalates!)....another reason (along with lack of seasonal eating, lower nutrient density) that this is increasingly a modern problem.

• Even occasional spikes in oxalates in the diet can result in adverse effects (page 124).

• Various factors create the perfect storm for oxalates to accumulate in tissues, including inflammation, low oxygen and acidity (page 129).

• There is a relationship between glandular disease / hormones and high oxalic acid intake (page 136), particularly in the thyroid (hypothyroidism and high TSH, for example).

• Inflammasome (immune process that causes the release of prostaglandins) may explain the link between oxalates and breakdown of connective tissues….lightbulb!…is this the link with hypermobility that seems to be prevalent in this population?....myself included.

• The link with autoimmunity may be explained by oxalates being “low-lying disrupters” that over tax the immune system (page 138), which explains why she sees that autoimmunity often decreases when people follow the diet long term.

• To clear oxalates, the author recommends a threshold below 30mg (page 185), but reducing oxalates is not a simple process and can be accompanied by significant adverse effects so following a protocol or working with a practitioner is imperative.

• The author recommends not only reducing dietary oxalates slowly, but also reducing vitamin C slowly (half every 5 to 7 days until 50mg twice daily) (page 188). Buy don’t throw out the Vit C…she argues that a small amount is beneficial!

• After going low oxalate, the body can become more sensitive to oxalates (due to overcapacity with clearing activity and absorbing a higher percentage) (page 193).

• She notes that food sensitivities (different from allergies!) may resolve on a low oxalate diet and that to test, eliminate the food for two weeks and then reintroduce in generous services for a couple days to gauge how reactive the body is (page 212).

• Oysters are a nutritional powerhouse: omega 3 fatty acids, vitamin D, vitamin B12, protein and minerals (zinc, iron, selenium and copper) (page 213). Interestingly, I keep coming across recommendations to eat more oysters!

• The cabbage family, although low in oxalates, should be eaten in moderation because, as the author notes, it can aggravate reflux, SIBO and IBS. She recommends always fermenting or cooking. Hmm, raw broccoli has never appealed to me, that’s for sure!

• Minerals are super important for activating B vitamins. Her top minerals picks are calcium, magnesium and potassium. Salt (essential for adrenal function!), sulfur and trace minerals are super important. Increasing my mineral intake has been a personal push the last few months as I keep reading more and more about how important this is! She gives helpful information for dosing and timing of supplements as well. For example, dairy or calcium is best taken 15 to 30 minutes before meals or when experiencing low energy (page 238) and away from vitamin D (so the calcium remains in the colon). And check your magnesium forms…magnesium glycinate, when taken in large quantities, can be converted to oxalate in the body (page 239)! She warns that before supplementing with potassium to get kidney function tested (eGFR should be over 60 to sufficiently clear excess potassium) (page 243). And maybe sodium shouldn’t be so villainized (especially if an overload of oxalates is depleting sodium)…the author suggests that more is needed than we generally think to avoid “low blood sugar, lethargy and heart palpitations” (page 244). And when sodium is low, the sodium retaining hormones may increase fibrosis….personally, I wonder if this has played into my scleroderma-type symptoms! As a teenager and young adult, I avoided salt like the plague because I thought, like fat, that it was unhealthy….how wrong, again, I was!

• This book cleared up some questions I had on sulfur, which I keep hearing about! Sulfur compounds can lower oxidative damage, heal connective tissue damage and aid in healing generally, which is why MSM/DMSO2, SAMe, DMSO, taurine and glutathione can be helpful for a variety of symptoms. I’ve recently ordered a topical MSM with magnesium and will be giving this a try! She notes that molybdenum can help with sulfur metabolism, for people who are sensitive (page 249).

• The citrate form of minerals (including lemon juice!) can be helpful for binding to oxalates, which helps them to dissolve and leave the body, which is why citrate helps with kidney stones (page 254).

• A B vitamin deficiency (particularly thiamin, biotin and B6) can increase endogenously produced oxalates! More evidence for my liver eating habit! She notes that most recovering from oxalate toxicity need B vitamins to recover.

The book also contains some great resources, such as food lists that incorporate a lot of the quality oxalate testing that has been done. Other resources I found helpful were a food swap chart, various recipes incorporating minerals, supplement recommendations and a mineral bath formula. For anyone who suspects they are dealing with oxalate overload, this book is a great resource and an eye opener!

Note that reviewed books have not been fact checked against scientific literature and that I do not endorse information or recommendations given in reviewed books. The book reviews serve to provide my personal takeaways and spawn potential interest in the subject matter for future research, follow-up or reading.