Green smoothies in moderation can be a great way to get extra vitamins, minerals and antioxidants. But, excessive intake of green smoothies may increase your levels of oxalic acid and this can lead to aching muscles and joints, gout, kidney stones and other health problems.
Handy hints to know whether it’s doing you more harm than good!
Have you experienced any of the following symptoms lately?
Kidney stones, pain or pressure
Urinary frequency, urgency or bladder infections
Arthritis or aching joints
By chance, was it soon after drinking a green, nutrient rich smoothie?
Unfortunately, your health kick may be doing you more harm than good! You see, these symptoms may be due to foods that are high in oxalates.
Individuals who love green smoothies may end up with excessive levels of oxalate which, in turn, could possibly lead to kidney stones.
What are oxalates?
Oxalate is produced as an end-product of metabolism of vitamin C, as well as of fructose and the amino acids serine and glycine. The body does not use oxalate for any purpose. Instead, it is excreted from the body through the urine or faeces. Even if oxalate intake is zero, it will still be present in the urine as a result of our body’s natural metabolism.
Which foods are high in oxalates?
Oxalate is generally found in plant foods and less commonly in animal products. Almost all plant or plant-based foods have moderate to high amounts of oxalate. The oxalate content is due to the incomplete oxidation of carbohydrates. Oxalates are found in many common foods such as caffeine in coffee and tea, chocolate, nuts and seeds, spinach and many varieties of fruits and vegetables.
Some plant foods with high levels of oxalates include, but are not limited to:
Leafy greens – spinach, Swiss chard, kale, collard greens, Brussel sprouts, celery, parsley, endive, beetroot greens, dandelion greens, and turnip greens.
Root crops – beets, carrots, potatoes, sweet potatoes, and parsnips.
Nuts and seeds – peanuts, pecans, beans, buckwheat, and poppy seeds.
Broccoli and okra.
Apples, apricots, concord grapes, oranges, star fruits, and berries (strawberry, raspberry, blackberry, blueberry).
Black pepper
Tea leaves, cocoa, and cocoa products (yes, including chocolates)
What happens if your body has excessive levels of oxalates?
Excessive amounts of oxalate can overflow into the urine and lead to kidney problems.
There is a rare genetic disease where the liver produces excessive amounts of oxalate. However the usual cause is the absorption of too much oxalate in the digestive tract. This is typically a result of intestinal diseases and frequent consumption of foods rich in oxalates.
High levels of oxalic acid have other consequences
Oxalate binds with and inhibits the absorption of calcium. The combination of oxalate and calcium results in an insoluble solid crystal. Small crystals can be excreted in urine without causing any problems. Large crystals can result in kidney stones. In general, since only up to 40% of blood oxalates originate from food, and since most individuals have no issues with calcium oxalate kidney stones, it is unlikely that most people will have problems from routine enjoyment of the foods containing high amounts of oxalate, especially if your gut and gallbladder are healthy.
The health problems caused by too much oxalates does not end with kidney stones. Aside from calcium, oxalate is also attracted to other molecules like iron. The combination of oxalate and iron called iron (II) oxalate has a major role in gout. Foods rich in oxalate must therefore be avoided by people who are susceptible to, or are already suffering from gout.
It is also possible for someone who has a “leaky gut” to suffer from excess oxalates. In leaky gut, there are gaps between the cells of the intestinal walls, allowing them to absorb large amounts of oxalates.
A build up of oxalic acid may cause and/or exacerbate certain diseases like arthritis, asthma, fibromyalgia, thyroid disorders, vulvodynia (pain in the vulva triggered by touch and pressure), thyroid disease, and a variety of digestive disorders. It is also associated with depression and autism.
How Can You Reduce Oxalic Acid Levels?
Hyperoxaluria may be managed by switching to a lower oxalate diet. Many individuals have reported some improvement with such a method. But then again, since the oxalate content of food varies, the following tips may help to reduce the effects of oxalate from your oxalate-rich foods:
Boil leafy greens then discard the water. Boiling a plant allows a significant amount of its oxalate content to be released into the boiling water. Steaming can also reduce the amount of oxalate in food, but not as much as boiling does.
Vitamin B6 deficiency could also be a contributing factor. According to researchers, low serum vitamin B6 may cause accumulation of a compound called peroxisomal glyoxylate, which is oxidized to oxalate.
Eat calcium-rich foods and consider taking calcium citrate supplements if you have had calcium-oxalate stones. Calcium binds to oxalate, rendering it insoluble and therefore much harder to absorb in the gut.
Minimise or avoid vitamin C supplements. You can just get your daily dose of this vitamin by drinking orange or lemon juice. That way, you are also ingesting citrate, which can help reduce your risk for kidney stones.
Try a probiotic supplement – some bacteria may aid in the degradation of oxalate in the intestines. These include Lactobacillus acidophilus and Bifidobacterium lactis. According to studies, taking probiotic supplements after your last meal for the day may help reduce the amount of oxalate in urine by about 33%.
And yes, as the title suggests, do avoid too much oxalate-rich vegetables in your green smoothies. The people who are most prone to oxalate overdose are the same ones who like the idea of juicing or blending vegetable smoothies as part of their diet. People think they are doing the right thing but juicing two litres of spinach, beetroot, celery and carrot can potentially be a health hazard.
What This Means To You
If you suspect that you might be suffering from too much oxalic acid, or for that matter, any food intolerance, see me with a neatly written or preferably typed four day food and symptom diary so that I can help you get your health and energy back on track!
Wishing you great health,
Dr Pete
PS. you are welcome to share this with friends and family
About Dr Pete
Dr Peter Holsman is a qualified Medical Practitioner, Naturopath and Professional Speaker based in Melbourne. An expert in his field with over 30 years experience, he specialises in treating people with fatigue related illnesses including anxiety, stress, depression, chronic fatigue syndrome,menopause, thyroid and adrenal hormone problems.