Oxalates: A possible cause of pain and illness?

Have you ever started a juice cleanse or health kick and ended up feeling worse? Have you ever drank spinach-based smoothies and felt unwell? For some people, regular consumption of highly promoted superfoods can cause chronic health issues.


Oxalates are formed from oxalic acid which is present in a number of foods. High levels can be found in foods like spinach, beetroot and nuts. It is not unusual for plants to contain substances that are inhospitable to humans. It is most likely part of a self-defence mechanism, designed to protect their existence.

Our bodies also make oxalic acid, which can form oxalate crystals and cause pain, stiffness and inflammation in muscles and joints. It can also aggravate the gut lining making it difficult to recover from a ‘leaky gut’. The science is out as to why some people are more susceptible to oxalate issues than others but factors like gut dysbiosis, low levels of B6 and a diet high in oxalate-rich foods might all be important.

The most obvious sign that reducing oxalates in your diet is warranted would be the presence of kidney stones or a family history of them. However, oxalate crystals do not just affect the kidney but can also migrate to other areas causing joint/muscle pain, inflammation in the gut and they have also been linked with autism.

How do you know if oxalates are an issue for you?

First, check the health issues listed below to see if you struggle with one or more of them:

  • fibromyalgia
  • migraines
  • dizziness
  • brain fog
  • urinary issues
  • joint pain/stiffness
  • inflammatory bowel disease
  • kidney stones

Then, identify whether your diet contains high oxalate foods. Do you consume any of the following foods regularly or in large amounts?

  • spinach
  • potatoes
  • cocoa
  • almonds
  • cashews
  • peanuts
  • beans
  • beetroot
  • sweet potato
  • tahini
  • raw carrots

How to reduce oxalates in your diet

Begin to move slowly and carefully towards a diet that is lower in oxalates. Please do this very slowly to avoid any serious increases in your symptoms. Elimination of high oxalate foods from your diet in one go is not recommended. Instead, a slow and steady decrease is recommended.

When oxalates are lowered in the diet, stored oxalates tend to be released from the tissues. This is known as ‘dumping’. This process can lead to an increase in symptoms, some of which may be difficult to manage and can cause extreme pain. Choose just one food to eliminate at first and, after two weeks, you can then focus on eliminating another food. This can continue, slowly, until your diet is focused mainly on low oxalate foods.

When you begin the process of moving towards a low oxalate diet you can run an organic acid test to identify the level of oxalates in your urine. This needs to be conducted by a lab that measures oxalic acid. This result, in combination with your experience of a low oxalate diet, will give you the best indication of whether oxalates are an issue for you.

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

Share this article with a friend
Birmingham, B13 8JP
Written by Sarah Hanratty
Birmingham, B13 8JP

Sarah is an experienced practitioner at the Brain Food Nutrition Clinic specialising in the link between gut health and physical and cognitive well-being.

Show comments

Find a nutritionist dealing with Healthy eating

All nutrition professionals are verified

All nutrition professionals are verified