Ever heard of Oxalates? Most Likely If You Suffer from Kidney Stones!

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If you’re prone to kidney stones, you might have wondered, “Why me?” Some people never experience this affliction in their entire lives, while others get them annually like clockwork. In your research, you may have stumbled upon dietary tips like limiting uric acid and another lesser-known culprit: oxalates.

What are Oxalates?

Oxalates, or oxalic acid, are natural molecules in many plants, serving as a defense against predators. They’re high in some foods and also made by our bodies as waste.

When eaten, oxalates can attach to minerals like calcium in the gut to form calcium oxalate, the most common type of kidney stone. This reduces mineral absorption, which can lower the levels of minerals available from our diet and potentially harm health if taken in large amounts.

What Foods are High In Oxalates?

In food, high levels of oxalates are found in spinach, rhubarb, beet greens, nuts, chocolate, tea, and some other plants. While oxalates are not a problem for most people, they can pose health issues for individuals prone to kidney stones or those with certain metabolic disorders that affect oxalate processing.

See Related: Top 10 Foods with the Highest Amount of Oxalates!

How Do Oxalates Lead to Kidney Stones?

1. Binding with Calcium: Oxalates in the digestive tract can bind with calcium to form calcium oxalate, which is a key component of the most common type of kidney stones. This binding typically happens in the colon but can start as early as the small intestine.
2. Low Urine Volume: When the body does not hydrate sufficiently, urine becomes more concentrated with substances like oxalates and calcium. This higher concentration can facilitate the crystallization and formation of stones.
3. Decreased Calcium Absorption: Consuming foods high in oxalates can reduce the amount of calcium absorbed by the body from the diet, as oxalates bind to calcium in the intestines. When less calcium is absorbed into the bloodstream, more is left in the intestines to combine with oxalates, potentially forming stones.
4. Increased Oxalate Absorption: Some conditions, such as certain gastrointestinal diseases or surgeries, can increase the absorption of oxalates from the intestines into the blood. This increase can lead to higher oxalate concentrations in the kidney, where stones form.
5. Genetic Factors: Some individuals have a genetic tendency to absorb more oxalates from their diet or to excrete higher levels of oxalates in their urine, both of which can increase the risk of kidney stone formation.

Symptoms That May Indicate High Oxalate levels

1. Kidney Stones: The most direct symptom related to high oxalate levels is the formation of kidney stones, particularly those composed of calcium oxalate. Symptoms of kidney stones include severe pain in the back, belly, or groin, painful urination, and urine that is pink, red, or brown.
2. Frequent Urination: An increased urge to urinate, sometimes accompanied by pain, can be a symptom of kidney stones from high oxalate levels.
3. Cloudy or Foul-Smelling Urine: High oxalate levels can cause urine to become cloudy or foul-smelling, indications of possible kidney stone formation or urinary tract infections.
4. Nausea and Vomiting: These symptoms can occur if kidney stones or high oxalate levels lead to kidney infection or severe blockage.
5. Blood in Urine: This can happen when a kidney stone caused by high oxalates moves through the urinary tract, causing irritation or injury.
6. Reduced Urine Output: Despite frequent urges to urinate, the actual amount of urine produced may be less if kidney stones block the flow of urine.
7. Pain During Urination: This can occur if oxalate crystals or kidney stones pass through the urinary tract.

Being Proactive About Oxalates

If you suspect you have high oxalate levels, consult a healthcare provider who can evaluate your symptoms and dietary habits. They may recommend a 24-hour urine test to measure oxalate excretion or a blood test to check oxalate levels in your bloodstream. Kidney function tests might also be suggested to assess any impact on your kidneys. Additionally, a diet review with a registered dietitian can help you understand your intake of oxalate-rich foods and make necessary adjustments.

For those concerned about kidney stones or kidney health, imaging tests such as ultrasounds or CT scans may be conducted to detect abnormalities. Seeking professional advice is important for appropriate testing and management of high oxalate levels.

See Related: How Much Fiber Do We Really Need & What are the Best Sources?

Common Questions Answered:

Q: Where are oxalates stored in the body?
A: Oxalates are not stored in the body; they are typically filtered through the kidneys and excreted in urine. Any excess oxalate that does not get excreted can combine with calcium to form crystals, which may lead to kidney stones if not properly managed.

Q: How to eliminate excess oxalates?
A: To eliminate excess oxalates, increase your fluid intake to help flush them out through urine, consume a balanced amount of calcium-rich foods which can bind to oxalates in the gut and reduce absorption. Also limit high-oxalate foods in your diet if you are prone to kidney stones or have been advised by a healthcare provider.

Q: Can oxalates cause constipation?
A: Oxalates themselves typically do not cause constipation. However, some high-oxalate foods are also high in fiber (like spinach). Not consuming adequate water, might contribute to constipation. Always ensure adequate hydration when consuming high-fiber diets.

Q: How many oxalates should you have per day?
A: There isn’t a one-size-fits-all answer to how many oxalates should be consumed per day. It depends on individual health needs and conditions. Generally, a typical adult diet may include anywhere from 150 to 500 milligrams of oxalates per day. However, those with a history of kidney stones or high oxalate levels may need to limit their intake significantly. Be sure to speak with a medical expert.

Example: A small serving (about 30 grams or 1 cup of raw spinach) contains approximately 225 mg of oxalates.

References

Kidney stones - Symptoms and causes - Mayo Clinic, Get Kidney Stones Treatment | Cleveland Clinic, Eating, Diet, & Nutrition for Kidney Stones - NIDDK (nih.gov)