Yes you read the title right. Though 2/3 of our population is currently considered obese, as people load up on high fructose corn syrup-filled sodas, deep fried doughnuts and fried chicken, pizza and fast food supersized meals…green smoothies can be the thing that can “devastate” your health?! Yes, green smoothies, that are made of raw green vegetables and fruit. As preposterous as this claim will surely seem to you, read on.
Recently, an anti-green smoothie blog was published and some of you asked me about it. In a blog titled, “How Green Smoothies Can Devastate Your Health,” posted on the Healthy Home Economist blog, the author argued that green smoothies could raise oxalate levels in people with oxalate toxicity. She then went onto describe the devastating effects this could have on health – ranging from fibromyalgia and kidney stones to oxalate stone formation in the brain. This type of fear-based, sensationalist nutritional information concerns me greatly, because it can keep people from eating the healthy foods their bodies need.
What Are Oxalates?
Oxalates are organic acids that occur naturally in humans, animals, and plants. They exist naturally in the human body. Likewise, our bodies convert many of the things we consume (like vitamin C) into oxalates. When combined with sodium and potassium, oxalate forms soluble salts. When combined with calcium, however, oxalate produces calcium oxalate, which can form kidney and other types of stones. This occurs because calcium oxalate is relatively insoluble, so it combines and hardens instead of harmlessly excreting as a waste product.
- Some conditions require oxalate restriction (50 mg per day or fewer), but these conditions are extremely rare. Conditions affected by oxalates are:
- Primary and enteric hyperoxaluria: A genetic predisposition to this disorder occurs in less than 1 percent of the population. In cases of genetic and enteric hyperoxaluria, strict oxalate restriction is required. Primary hyperoxluria (genetic) can lead to renal disease and renal failure.
- Dietary hyperoxaluria: Arising from dietary factors, this is more common condition, and is associated with the formation of calcium oxalate kidney stones. In cases where patients develop calcium oxalate kidney stones, physicians do recommend moderating intake of high oxalate foods such as animal protein. Kidney stones occur in about 10 percent of the population. Let me repeat that again: it is widely recommended to reduce animal protein in relation to kidney stones. High levels of animal protein may be a much, much larger contributing factor to this condition than vegetables, as the kidneys have to filter out the bi-products of protein digestion and metabolism.
- Hypercalciuria type II: Excessive urinary calcium excretion exists in less than 10 percent of the population. This condition, like hyperoxaluria, is associated with kidney stone formation. Interestingly, studies show that increasing dietary calcium intake restricts oxalate absorption.
Oxalates and Kidney Stones
There are oxalates in the foods you eat. Some foods, such as spinach and rhubarb, contain higher levels of oxalates than others. If your body absorbs high levels of oxalates and does not process it well, it may result in the formation of calcium oxalate stones, which most commonly form as kidney stones. Some people are more predisposed to this condition than others. No clear evidence exists linking dietary oxalate restriction to formation of fewer calcium oxalate kidney stones, however.
Some foods increase oxalate levels in the body more than others. These include rhubarb, soy, dark leafy greens, beets, chocolate, wheat bran, and tea. According to the Canadian Medical Association Journal, however, you can mitigate the effects by drinking fluids and consuming more dietary calcium.
Oxalates in Natural Food
The topic of how oxalates in natural foods like spinach affect people with hyperoxaluria remains the subject of debate among experts. In his book Conscious Eating, Gabriel Cousens MD theorizes that eating oxalates in natural foods like spinach does not build up oxalate levels in the body as long as fat metabolism and digestion work properly. Cousens goes on to quote Dr. Norman Walker, author of Raw Vegetable Juices, stating that cooking oxalic acid-containing vegetables is what causes an irreversible bind with calcium, leading to kidney stones.
Benefits of Leafy Greens
While oxalic acid may, indeed, cause a problem in a small percentage of the population, it would be a shame to allow fear of a condition that occurs in very few people to keep you from realizing the tremendous benefits associated with consumption of raw, leafy greens like spinach. With the vitamins, minerals, fiber, antioxidants and enzymes that have such a positive effect on your health, the benefits far outweigh the risk of developing a condition that affects such a small portion of the population.
Properly functioning metabolism and digestion offer protective benefits against oxalate related illnesses (see above). What’s the best way to ensure your metabolism and digestion function properly? Feeding your body the healthy, whole, non-toxic plant foods it was meant to eat. When you eat a diet full of healthful foods the body is intended to eat, it works more efficiently. As you detoxify, your body works more efficiently, as well.
Minimizing the Effects of Oxalate
- If you remain concerned, you can minimize the potential effects of oxalates
- Eat plenty of dietary calcium from plant-based sources.
- Rotate your greens. Change up your Glowing Green Smoothie recipe, as I’ve always encouraged, and switch up the salads so you are eating a variety of greens and other non-starchy vegetables.
- Minimize juicing if you have formed calcium oxalate kidney stones in the past or are concerned about oxalate. Juicing may be more problematic because you are removing parts of the whole food (including fiber), and thus increasing concentrations of other substances. A smoothie, however, contains every part of the whole food, which is the way nature intended food to be consumed, which may minimize oxalate problems.
The Bottom Line
While some experts express concerns about oxalates, others have the exact opposite opinion. With today’s highly processed diet, it’s not surprising that some humans react to elements in the foods our bodies were meant to eat (whole, raw, plant-based foods). Eliminating these foods and returning to a more pure, natural way of eating, however, can help restore health and vitality. With so many benefits to eating dark leafy greens, it’s a shame to allow fear of a condition that occurs in a small minority of people to keep you from achieving vibrant health.
What do you think? I’d love to hear your opinions about oxalates, and I’d definitely like to hear have the author of the original article respond to the points made here.