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Tired & Achy Even Though You Eat Healthy?An ‘Anti-Nutrient’ in Nuts & Some Veggies May to Blame, Say Doctors

The telltale sign of oxalate overload: Cloudy urine. Here's what to look for — and how to flush them

These days we hear a lot about foods that have made it into the health food Hall of Fame: foods like kale, sweet potatoes and almonds come to mind. Doctors and nutritionists praise these foods for being healthy for everyone, all the time. But that well-meaning advice can feel frustrating for those of us who have been faithfully trying to eat healthy for years, yet still feel tired and achy. Researchers have identified one possible culprit: oxalates. These compounds, which function as a kind of ‘anti-nutrient’ are found in many otherwise health foods and can make people feel sick, achy and tired. “Make no mistake, every human being on planet earth is sensitive to oxalates above a certain level,” says diet expert Ken Berry, MD, who overcame oxalate overload himself. Keep reading to learn everything you need to know about this sneaky overload, how to flush oxalates from body to regain your health and how doing so helped Sally K. Norton, 59, ease her pain, restore her energy and even reverse osteoporosis.

What are oxalates?

Oxalates, sometimes referred to as oxalic acid or OX, are natural plant compounds that function like chemical toxins. Our bodies can make them, but we also get them from eating certain foods, such as:

  • Potatoes
  • Beets
  • Spinach & kale
  • Almonds
  • Dates
  • Raspberries
  • Navy beans
  • Soy

Oxalates occur in nature as a form of self-defense for the plant, a means of deterring animal predators from grazing on it. Under a microscope, oxalates look like tiny needle-shaped crystals. If you’ve ever enjoyed too much pineapple and felt the inside of your mouth become irritated, that’s a sign of oxalate irritation. (Check out this list of high- and low-oxalate foods.)

What are the dangers of high oxalates?

When we consume a high level of foods containing oxalates, the compounds can circulate in the bloodstream and even build up in tissues, triggering chronic tiredness, pain, brain fog and a host of other ailments. “A buildup of oxalates and resulting nutritional deficiencies can lead to bloat, joint pain and fatigue,” explains Sara Gottfried, MD, author of Women, Food and Hormones.

Adds Sally K. Norton, MPH, author of Toxic Superfoods, “These crystals can destroy the very machinery of life: cell membranes.” So even though oxalates occur in healthy foods that contain vitamins and minerals we need, they’ve been deemed an “anti-nutrient” because they can block the absorption of vitamins and minerals, say researchers from Harvard. They also collect in delicate tissue found in the thyroid or vulva and create irritation there.

Why you may not have heard of oxalates before

Historically, most doctors only considered oxalates a problem when they accumulated to form kidney stones. In those cases, doctors recommend a low-oxalate diet to protect their bodies. But new research suggests that oxalates can cause problems at much lower levels.

Related: MD Reveals the Kitchen Staple That Outsmarts Painful Kidney Stones For Pennies

Complicating matters is the fact that women and their doctors often chalk up oxalate symptoms to normal aging. In fact, oxalates have been called “the great pretender,” explains Dr. Berry, since “the inflammation they trigger can mimic rheumatoid arthritis and IBS, even anxiety and ADHD.”

What’s more, since oxalates block mineral absorption, they create nutrient deficiencies that can make people feel even worse. David Perlmutter, MD, confirms, “Oxalates steal calcium in the body, weakening women’s bone health.”

Related: “I Reversed a Glutathione Deficiency and Got My Energy and My Life Back!”

Who is prone to oxalate issues?

Anyone can suffer from a build-up of these particles. But popular diets like vegetarian, Paleo and keto are especially high in oxalates. People with a history of antibiotic use or poor diet (both of which weaken the gut lining) are also at risk of oxalate overload. The reason: The toxins can leak into the bloodstream, where they weaken the function of any cells they pass by, according to Case Western Reserve University research.

Related: If Weight Loss Won’t Happen (No Matter What You Do), You Might Have Leaky Gut

Symptoms of oxalate overload

If you suffer from fatigue and two or more of the following symptoms, an overload of oxalates may be the cause:

  • Cloudy urine
  • Joint pain
  • Brain fog
  • Kidney stones
  • Skin rashes
  • Poor circulation
  • Low bone density
  • Vulvar pain

Testing to find out if you have oxalate build up

Unfortunately, science hasn’t discovered a perfect oxalate test yet. Some functional medicine doctors will test urine with an organic acids test, or O.A.T. But those tests can be hard to interpret and may provide false-negative results. Standard blood testing is even less reliable, given that people often have to fast from food for 12 hours before a blood draw, giving time for ingested oxalates to fall from their peak accumulation ranges. Plus, many traditional doctors may not be educated about oxalate issues.

In lieu of concrete medical tests, some experts recommend an easier at-home method to gauge oxalate accumulation. Simply look at your morning pee. Having chronically cloudy, strong-smelling urine is the surest sign of oxalate crystal overload in the body.

Related: Your Tiredness May Be Caused By A Food Sensitivity: The Best At-Home Tests

6 ways to flush oxalates from the body to heal

If you suspect you’re suffering from oxalate overload, Norton offers words of encouragement: “When oxalates leave the body, it’s possible to heal tissues and reverse chronic conditions.” Follow these easy tips to begin to feel better…

1. ID the worst offenders

Diet changes are proven to help. So limit intake of the highest oxalate foods: almonds, spinach, beets, chia seeds, peanuts, dark chocolate, amaranth, turmeric and sweet potatoes. This allows the kidneys to flush the body of excess oxalates. (Click to learn more about following a low-oxalate diet for weight loss.)

2. Make simple swaps in your diet


Eating a low-oxalate diet doesn’t mean you have to starve or feel deprived. Most high-oxalate foods have lower-oxalate equivalences. Instead of kale in salads, reach for romaine lettuce. Instead of almond butter, try sunflower butter. Easy substitutions will give the body time to catch up on flushing stockpiled oxalates from the body. Nutritionist Ann Louise Gittleman, PhD, NY Times bestselling author of over 35 books, suggests “green cycling:” For five consecutive days per month, trade high-oxalate greens for low-oxalate lettuce and arugula while also avoiding other top sources.

3. Start slowly

It’s best to decrease your oxalate intake slowly. People who eliminate oxalates ‘cold turkey’ may experience detox flare-ups, sometimes called “dumping,” such as headaches and rashes. Learn more at the Trying Low Oxalates Facebook group.

4. Boost energy with B vitamins

Overload of oxalate demands more B vitamins, so experts advise supplementing. Try taking B vitamins, like Klaire Labs Active B Complex (Buy from NHC, $31.99 for 60 capsules).

5. Mop up oxalates with calcium

Remember how oxalates like to poach calcium from the body? Strategically supplementing with a calcium tablet (without vitamin D) can fuse to oxalates like a magnet and help remove it from the body. Norton, (whose healing success story is below), explains, “Keeping your vitamin D separate — by at least 2 hours — allows more calcium to remain in the colon, where it lowers oxalate absorption and supports oxalate excretion.”

Start slowly with 250 mg of calcium citrate twice daily (morning and bedtime) and build up to four times daily. Try: Nature’s Way Calcium Citrate (Buy from Amazon, $11.99 for 100 capsules).

6. Be aware of vitamin C

This common vitamin converts into oxalate, so it poses a double-edged sword for health. Some vitamin C is needed to support immunity, while too much can drive up oxalate levels, according to research at the University of Alabama. Endo-urologist Joseph Crivelli, MD, reports, “Vitamin C is the main dietary precursor for making oxalates in the body.”

In fact, long-standing research published in the Journal Urology found that taking 500 mg or more of vitamin C a day causes a significant increase in urinary oxalate. To strike a safe balance, experts advise keeping C intake between 60 and 250mg daily, from fresh foods or supplements (look on labels to see if you’re getting unexpected doses from fortified foods). And bump up to 400 mg when sick.

Oxalate overload success story: Sally K. Norton, 59

Sally K. Norton, who flush oxalates from body to restore her health
Tyler Darden

How can I be this tired, Sally K. Norton wondered, unable to stand for the receiving line at her own wedding. “I was doing the best I could sitting on a stool, but my limitations were on full display that day. There was no dancing. Standing for my vows was all my sore joints could manage. My mother even told the groom he’d gotten ‘defective goods.’ Little did I know my mysterious symptoms would outlast my marriage.

 “Having my tonsils removed as a kid taught me something: I never wanted to be sick again — it meant having no fun. So I focused on eating healthy, even growing my own vegetables. But over the years I developed debilitating pain in my feet and back, needing 3,600 mg of prescription pain medications daily. I was forced to take a break from the physical labor of gardening. And I felt a little better for a while.

“Slowly, my extreme fatigue returned. After some testing, a sleep doctor told me, ‘You’re waking up 29 times every hour.’ No wonder I was tired. But sleeping pills didn’t even help.

Healthy diet changes made Sally feel worse

After some research, I learned that toxicity and poor gut health were the cause of many sleep disorders so I tried to improve my digestion. But the cleaner I ate — giving up dairy for nut milk, and giving up gluten for sweet potatoes — the worse I felt.

Suspecting food allergies, I went to a doctor, desperate for help. He only told me, ‘You’re acting crazy. I’m referring you to psych services — you’re a food neurotic.’

“My symptoms persisted, sometimes better, sometimes worse, but always without rhyme or reason. Making it through a yoga class became impossible as my body only grew more stiff. But I’d studied health and nutrition at some of the top schools in the country. What am I missing?

“Then an attack of vulvar pain led me to learn about a low-oxalate diet — a little-known diet aimed to avoid foods that can contribute to the crystals that form kidney stones and related pain. I gave it a try and felt better. (The Vulvar Pain Foundation was a big help.) And as the pain lifted, I drifted back to my usual habits. Honestly, I always had so many health complaints I never knew which one to focus on next.

“Over time, my brain fog took center stage. Soon, I couldn’t concentrate to read a book, let alone the mail. Despite my strong work ethic, I had to quit my job as a grant writer. But I simply couldn’t will my way out of this agony. I felt like I was in my 80s and aging rapidly, always needing crutches or wheelchairs, even suffering from weak bones. That’s when I thought back to that doctor who basically called me crazy and knew no one was going to save me. I had to figure this out myself.

The solution that ended Sally’s pain and fatigue

“When my pain flared again, I begrudgingly returned to the low-oxalate diet from years earlier. I figured I’d try it for 10 days. What happened next amazed me: Not only did my arthritis pain lift, but my debilitating sleep disorder and brain fog vanished too. I never thought those ailments were connected. I was perplexed and skeptical, but I couldn’t deny that multiple miracles were unfolding in my health. Soon, I was confident I was flushing harmful oxalates from my body.

“I longed to understand how something as simple as trading high-oxalate sweet potatoes for low-oxalate turnips could make such a dent in my decades of suffering. So I scoured libraries at medical schools and the National Institutes of Health and I taught myself everything I could about oxalates. These toxins found in plant foods can build up in the body — in more places than the kidneys — and trigger countless health issues. Learning I was sensitive to and overloaded with oxalates was a slap-myself-on-the-forehead moment: I’d been poisoning myself with my healthy diet!

“That’s when I recommitted to a new way of eating: easily trading the highest-oxalate foods in my routine for lower-oxalate alternatives. This allowed my kidneys to slowly start removing the stockpile trapped in my system. I felt better in just one week. So I kept at it and within six months, I wore 3-inch heels and danced the night away at my nephew’s wedding!

Today, Sally is thriving

“Healing is still a journey and there can be setbacks, but for the first time in my life, I feel good, like I’m getting younger. Now I know I won’t be spending my golden years suffering in a nursing home. I even reversed my osteoporosis.

“Looking back, my old nutrition textbooks only devoted a 1-inch paragraph to oxalates. So I wrote an entire book called Toxic Superfoods to help other people. As I approach turning 60, my healing feels profound. Today I’m hopeful I can live to my nineties like my mother and grandmother — and enjoy it!”

This content is not a substitute for professional medical advice or diagnosis. Always consult your physician before pursuing any treatment plan.

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