Plant foods and leafy greens are popular among health-conscious individuals. However, most of these foods are rich in oxalate, an anti-nutrient with numerous health effects.
Therefore, it’s no shock that you’d want to know if garlic and other foods you love are high or low in oxalates. Here’s a detailed article about the effects of oxalates on your body and whether garlic is rich in oxalates or not.
Is Garlic Rich in Oxalates?
Compared to other spices and seasonings like fermented melon and beet leaves, garlic has a low oxalate content. For fresh garlic, the soluble oxalate content is 199.72 mg/100g compared to 315.19 mg/100g and 514.80 mg/100g for fermented melon and beet leaves, respectively.
However, according to research, oxalate content is different from their dry weights. For instance, garlic powder contains 210.28 mg/100g, while fermented melon and beet leaves contain 486 mg/100g and 600 mg/100g, respectively.
The study revealed that dry samples have higher oxalate content than fresh samples. Because of this, it’s safer to consume fresh high oxalate foods than their dried versions to avoid kidney stones and other consequences of oxalate poisoning.
With that said, below is a breakdown of what oxalate is and its effects on the human body.
What is Oxalate?
Oxalic acid is an organic compound present in many leafy greens, fruits, vegetables, seeds, nuts, and cocoa. In plants, oxalic acid is bound to minerals creating oxalate.
Now, the human body can obtain oxalate from foods or make its own. For example, vitamin C is often converted into oxalate after metabolism. Once it’s in the body, oxalate binds itself to minerals forming compounds like iron oxalate and calcium oxalate. This process happens in the colon and sometimes in the kidneys.
In some individuals, the oxalate compounds are eliminated through urine and stool. However, some sensitive people develop health problems, including kidney stones, when they are on a high oxalate diet.
Oxalate Reduces Mineral Absorption
The major health concern with oxalate is that it binds to minerals in the digestive tract and prevents them from absorption. For instance, spinach is a leafy green rich in oxalate and calcium. The oxalate keeps the body from absorbing calcium.
Eating Oxalate and Fiber May Also Hinder Nutrient Absorption.
Note: Although oxalate hinders absorption of some nutrients, it doesn’t affect others. For instance, calcium absorption from spinach might be reduced, but calcium absorption from milk isn’t affected when spinach and milk are consumed together.
May Contribute to Kidney Stones
Usually, small amounts of oxalates and calcium exist in the urinary tract but in a dissolved state, so they don’t cause problems. But from time to time, they form crystals which can form stones, especially when one is on a high oxalate diet and has low urine volume.
Tiny stones don’t cause problems, but large ones can cause nausea, blood in urine, and severe pain as they pass through the tract. While there are many variations of kidney stones, most are formed by calcium oxalate. Because of this, individuals who’ve had problems with kidney stones before are advised to reduce their consumption of foods rich in oxalates.
Do Oxalates Cause Other Problems?
Some health experts link high oxalate intake to autism and vulvodynia, a condition characterized by chronic vaginal pain.
Many Foods Containing Oxalates Are Healthy
Some low oxalate diet enthusiasts say it’s better to avoid foods rich in oxalates since they have negative health effects. However, avoidance isn’t so clear-cut. Most of these foods are rich in nutrients, including fiber and antioxidants. As such, it’s not recommended to stop eating them.
Should You Follow a Low Oxalate Diet?
If you’ve suffered from calcium oxalate kidney stones and your urinary tract is high in oxalates (according to a 24-hour urine test), you can benefit from a low oxalate diet. Switching to a low oxalate diet helps to reduce the risk of developing future kidney stones.
The general idea behind consuming a low-oxalate diet is lowering your oxalate intake, thus ensuring there’s less oxalate available in your system. This reduction results in minimal oxalate in your urine and reduces the risk of developing kidney stones.
What Constitutes a Low Oxalate Diet?
There’s no consensus on how much oxalate should be in a low-oxalate diet. Moreover, there’s a disagreement on the exact oxalate contents in some foods. However, the University of Chicago says that a reasonable oxalate intake should be under 100 mg a day and, if possible, under 50 mg a day.
This means you need to stay away from foods high in oxalate containing over 700 mg of oxalates in each serving. Some high oxalate foods are:
- Wheat germ
- Cocoa or chocolate
- Black teas
- Legumes like soybeans, peanuts, and beans
- Some tree nuts like hazelnuts, cashews, and almonds
These foods can increase oxalate levels in your urinary tract
Below Is a Quick Breakdown of High, Moderate, and Low Oxalate Foods in Different Categories:
Low Oxalate Food
- Beverages – coffee, water, lemonade, fruit juices like apple juice, white/red wine, pineapple juice,
- Dairy and substitutes – cream cheese, margarine and butter, milk, yogurt, sour cream, coffee creamer, whipped topping
- Fruits and berries – bananas, apricots, apples, grapes, lemon, melon, papaya, raisins, pears, peaches, plantain, cantaloupe
- Vegetables – cabbage, cucumber, mushrooms, onions, zucchini, squash
Moderate Oxalate Food
- Beverages – prune juice
- Fruits and berries – canned cherries, figs, orange
- Vegetables – asparagus, tomatoes, string beans, olives, mixed frozen vegetables, cooked carrots
High Oxalate Food
- Beverages – chocolate milk, hot chocolate, black tea
- Dairy and substitutes – soy cheese, soy milk, soy yogurt
- Fruits and berries – blueberries, dewberries, elderberries, blackberries
- Vegetables – spinach, yams, turnips, rutabaga, carrots, sprouts, beets, Brussels, celery, okra
Tips to Lower the Risk of Developing Kidney Stones
Aside from adhering to a low oxalate diet, you can do the following to improve urinary health and reduce the risk of kidney stones:
- Drink 12 cups of fluids (50% water), and drink even more in hot weather or when exercising. This prevents urine dilution and dehydration
- Consume 2-3 servings of dairy foods daily – if you take calcium supplements, prefer calcium citrate
- Eat 5-9 servings of vegetables and fruits daily
- If you have to take vitamin C supplements, don’t surpass 500 mg every day
If you want to follow a low oxalate diet, you can include fresh garlic in your recipes. Although garlic powder has higher oxalate content, it’s still considered low enough for a low oxalate diet.