Oxalic acid and organic acids

Oxalic acid and organic acids

Organic acids are found in numerous plant cells, but especially in fruit. The most famous representatives are malic acid, acetic acid, citric acid, tartaric acid, and oxalic acid. Oxalic acid is one of the anti-nutritional substances, as it reduces the availability of minerals and can promote certain diseases. lifebloombeauty

 

Oxalic Acid Basics

Metabolism Aspects

Oxalic acid is a water-soluble organic carboxylic acid produced by humans and animals in various metabolic processes and is then excreted via the kidneys (urine). futuretechexpert

 

5–50% of the oxalic acid excreted in the urine comes from food. The central part is produced in the metabolism, particularly from amino acids and vitamin C . naturalbeautytrends

 

Oxalic acid is absorbed throughout the gastrointestinal tract. The availability of sodium and potassium oxalate is relatively high, while calcium, magnesium, and iron compounds are low. smarttechpros

 

Since oxalic acid cannot be broken down in the body, it is excreted through the kidneys. The expected concentration in urine is less than 50 mg per day. If the intake through food increases significantly (> 180 mg/day), the amount of oxalic acid in the urine increases. techsmartinfo

 

Occurrence

Oxalic acid is only found in very high quantities in comparatively few foods. These include some vegetables (chard, purslane, spinach, rhubarb, beetroot, sorrel) and fruits (gooseberries) as well as nuts, cereal products (bran), coffee, black tea, and cocoa (chocolate).

 

Meat, sausage, eggs, and milk/milk products, and edible oils are almost free of oxalic acid or contain only minimal amounts.

 

The levels in food can vary greatly depending on the cultivation and variety. The same applies to different parts of the same plant. With rhubarb, the highest amounts are found in the leaves.

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Recommended intake

In healthy people, daily amounts between 600 and 700 mg usually do not cause any side effects / harmful effects. If the mineral intake of calcium, magnesium, iron, and fiber is sufficient, the excretion of oxalic acid in the urine is rather low.

 

Patients with kidney disease or a tendency to calcium oxalate stones should avoid consuming foods rich in oxalic acid.

Toxicity

For pure oxalic acid, the lethal dose is between 5 and 15 g. If swallowed, burns of the throat and gastrointestinal tract, intestinal bleeding, kidney failure, hematuria, cramps and circulatory collapse can occur.

 

Usual consumption habits deliver significantly smaller quantities, so food poisoning is unlikely. Exceptions in the past were the consumption of sorrel soup or rhubarb leaves.

 

The first signs that the intake is too high are an uncomfortable feeling in the mouth or the teeth becoming “dull” due to the build-up of oxalate compounds on the teeth.

Interactions and bioavailability

Dietary fiber: Dietary fiber in food can bind calcium oxalate crystals and soluble oxalates. The

 reduces the availability of oxalic acid.

 

Minerals: The simultaneous absorption of minerals (e.g., calcium, magnesium) can significantly reduce the absorption of oxalic acid in the intestine [ Jae 2004 ]. Hence the recommendation to consume foods rich in oxalic acid with milk/products in the case of an indicated low-oxalic acid diet. On the other hand, a one-sided diet (high oxalic acid intake, low mineral intake) can lead to a mineral deficiency.

 

Vitamin C: When vitamin C is broken down, the body produces oxalic acid. To what scope this has a negative effect, for example, on the formation of calcium oxalate stones, is unclear. To be on the safe side, we guide against high doses of vitamin C.

 

Microbiome: A few microorganisms in the large intestine (e.g., Oxalobacter formigenes) can break down oxalic acid. Oxalobacter formigenes is a natural component of the intestinal flora but can be significantly reduced or eliminated through repeated / long-term treatment with broad-spectrum antibiotics. As a result, the bioavailability of oxalate increases.

 

 

Soaking and boiling: The content of available oxalic acid in food dropped significantly when burning and absorbed as oxalic acid passes into the water.