low-oxalate diet

low-oxalate diet

Oxalic acid (chemical formula HOOC-COOH) is a strong

organic acid which is widely distributed in nature in both

 plants and animals. However, plants contain more than

 animals. The name comes from the plant Oxalis (wood

 sorrel) from which it was first isolated.

Oxalic acid has the ability to form a strong bond with various

minerals, such as sodium, potassium, magnesium, and calcium.

 When this occurs, the compounds formed are usually

referred to as oxalate salts.

 Thus, “oxalate” usually refers to a salt of oxalic acid, one of which is calcium oxalate.

Although both sodium and potassium oxalate salts are

 water soluble, calcium oxalate is practically insoluble,

which is why calcium oxalate, when present in high

enough levels, has the propensity to precipitate (or

solidify) in the kidneys or in the urinary tract to form

calcium oxalate crystals.

Calcium oxalate crystals, in turn, contribute to the

 formation of kidney stones. Approximately 80% of

all kidney stones are composed predominantly of

calcium oxalate. For reasons not yet fully

understood, women have a much lower incidence of
kidney stones than men.

Thus oxalate is a very simple sort of molecule that

links up with calcium and then crystalizes under

some conditions, including when it encounters

damaged tissues.

 The crystals formed this way can be quite

irritating and painful to tissues where they form,

causing or increasing inflammation.

These crystals can be especially painful if they lodge

themselves in places where they get in the way of the

movement of other things through tight places.

These physical issues are easy to understand, but

there are still many secrets nature has about how oxalates

interact with other parts of the metabolism.

 Where do oxalates come from?

Oxalates are present in a lot of plants and fruit that we
eat and in virtually all seeds and nuts.

Ordinarily, the gut  will not absorb much of the

oxalate from the diet, and the oxalate will be

metabolized by the flora or just leave the  body with the stool.

 Under other conditions, a lot of the dietary oxalate is absorbed,

 Over absorption is far more likely to occur when the

tight junctions between the cells which line the gut open up
and let molecules pass through between the cells in a

condition called the "leaky gut" which is similar to a

condition in the bladder with open junctions called the "leaky bladder".

Is oxalate found in most foods?

Most foods do not contain significant amounts of oxalate.

The primary sources of dietary oxalate are plants and plant

products. Although the physiological role of oxalate in

plants is not clearly understood, it is well established that a

number of plants have the ability to synthesize oxalate.

 Seeds and leafy plants related to spinach and rhubarb contain the most oxalate.

Other edible plants that contain significant concentrations of oxalate include—in decreasing order— (carambola), black pepper, parsley, poppy seed, amaranth, spinach, chard, beets,
when drinking milk with a rhubarb dessert is caused by precipitation of calcium oxalate , chocolate, most nuts, most berries , fishtail palms , New Zealand spinach and beans .
The “gritty mouth” feeling one experiences .
The calcium is abstracted from the casein in dairy products.

Leaves of the tea plant contain among the greatest measured concentrations of oxalic acid relative to other plants. However the infusion beverage typically contains only low to moderate amounts of oxalic acid per serving, due to the small mass of leaves used for brewing.

After the substance crosses the intestinal cell, it can leave the

cell to join the blood by means of a different set of

transporters that are on the blood or "exit" side. With this kind
of regulation coming from both sides of the cell, when the

body recognizes that you don't need more of a substance from food, the cell won't let more of that substance cross through.

 The body obviously loses that regulation when substances are absorbed through the "leaky" junctions between cells.

Oxalates are just one of the substances where this is a

problem, but whenever more oxalates are absorbed

like this, the result may be high levels of oxalates in

blood and urine and in tissues. Scientists call the high

levels in urine hyperoxaluria

Eating food high in oxalates is not the only way to get

high oxalates systemically. Our bodies make oxalates

on their own, especially when certain enzymes aren't

balanced in their activity. Normally, when oxalates are in

the gut, they may encounter particular species of

bacteria which will digest them and turn them into

something else that isn't so irritating.

This system of microbial digestion may be why the body

seems to purposefully route excess oxalate from the rest

of the body to the gut.
 
the very microbes we need to do this digesting of oxalates for

us are subject to being killed by antibiotics in common use.

Even if there was no exposure to antibiotics, these microbes

might not have colonized yet in very young children, for it does
not tend to be in breast milk, but must be picked up from the environment.

Lactobacillus acidophilus is an oxalate-eating species, but

when oxalates are in excess, lactobacillus can be killed off.

a probiotic formulation of a bacteria called oxalobacter

formigenes that helps digest oxalates even better than

lactobacillus is under development for patients with

hyperoxaluria and related conditions.

 

What is the function of oxalates in the body?

There is a positive side to oxalates because they

help us manage calcium, but the management of

oxalates themselves will fall down when cells are

low in glutathione and also in oxidative stress.

Oxalates add to that oxidative stress.

Plants use oxalates to protect themselves from infection or from being
eaten, as these crystals can tear up the mouths of the bugs that eat them,

but we haven't  learned nearly enough about the positive side of oxalates in humans.

but some of studies said that a small dose of calcium oxalate is

enough to cause intense sensations of burning in the mouth and

throat, swelling, and choking that could last for up to two weeks,

 We know a lot of negatives about oxalates,

Effects of over Ingestion: -

 In greater doses it can cause severe digestive upset, breathing difficulties, coma or even death.
 
Recovery from severe oxalate poisoning is possible, but permanent liver and kidney damage may have occurred.

The stalks of plants in the Dieffenbachia genus produce the most severe oxalate reactions. The needle-like oxalate crystals produce pain and swelling when they contact lips, tongue, oral mucosa, conjunctiva, or skin.

Edema primary is due to direct trauma from the needle-like crystals and, to a lesser extent, by other plant toxins (e.g., bradykinins , enzymes).
Depending on the plant ingested,

And you should know that  :
 
The presence of Oxalobacter formigenes in the gut flora can prevent this.

Cadmium catalyzes the transformation of vitamin C into oxalic acid and can result from smoking heavily,

Is the low oxalate diet difficult to follow, or impossible to stay on?

The list of foods that have been tested for levels of

oxalate is limited, though growing. However, with careful

food selection, a low oxalate diet which provides all the

needed nutrients and is reasonably varied can be followed.

You must remember that :

with any lifestyle change you should cut back in moderation.
It is not reasonable to cut out fruits and vegetables from

your diet, as they provide so many important nutrients.

Many fruits and vegetables have low oxalate content and can

be regularly included in your diet .

It is important to know that :

Oxalate content of a single food group varies based

on the time of year, the type of soil it is grown in

and a host of other factors specific to the growing

conditions of the plant.

Oxalate content schedules

Oxalate Content Group	Total Dietary Fiber in Grams	Name
	Fruits
Medium Low Medium Low Medium	3.7 2.8 3.1 4.0 3.0	1 large apple with skin 1 banana 1 orange 1 pear 5 prunes, drained
	Vegetables
Low Low Medium Medium Medium Low Low Medium	1.3 2.0 1.8 7.8 0.8 3.5 8.1 1.6	½ cup raw broccoli ½ cup brussel sprouts, cooked ½ cup raw carrots ½ cup cooked lentils 1 cup iceberg lettuce, shredded ½ cup green peas, canned ½ cup split peas, cooked ½ cup potatoes, boiled
	Grains
Medium Medium Medium Low	0.6 3.0 3.5 1.7	1 slice white wheat bread ¾ cup oatmeal 1 cup brown rice, cooked 1 rye crispbread wafer
	Others
Medium	1.9	1 piece apple pie
Low	23.4	Total fiber in all Low Oxalate foods in this chart
Medium	2.8	Average fiber per Medium food in this chart
Combined	29.0	Total fiber in 7 Low foods and 2 Medium foods

 

Does a person following the low oxalate diet need to completely eliminate all oxalate for the diet to be effective?

Foods with only low levels of oxalate do not need to be completely eliminated. The propensity for the

consumption of a specific food to increase urinary

oxalate is a function of both A) The amount of oxalate in that food and B) The amount of oxalate which can be

absorbed from that food.

Since dietary oxalate is not efficiently absorbed into the

 body, the consumption of foods which provide low levels

of oxalate will not have a significant effect on the amount

of dietary oxalate which enters the body through the

gastrointestinal tract or on the amount of oxalate which

is excreted via the urine.

Does drinking water (tap water, spring water, distilled water) contain oxalate?

Water is not a dietary source of oxalate unless the

water has come in contact with high-oxalate plants

(e.g., water that high-oxalate plants have been cooked in).

Hard water (which contains calcium and magnesium) is

 likely to exert a beneficial effect with respect to oxalate

absorption because these minerals will tie up much of the

oxalate consumed in the diet within the gastrointestinal tract,

thereby decreasing oxalate absorption.

Less oxalate absorption translates to less oxalate gaining access

to various tissues within the body.

 

Is a low oxalate diet nutritionally inadequate?

There are certain nutrient intakes which could be

compromised in a low oxalate diet. For example, low

oxalate diets may provide lower levels of nutrients

which are found primarily in plant products, such as

vitamin C and folate. However, with wise food selections, an

individual can maintain a low oxalate diet and still consume

recommended levels of all key nutrients.

Hyperoxaluria and kidney stones :

Hyperoxaluria, defined as excessive urinary oxalate, is a common

abnormal finding in patients with calcium oxalate kidney stones.

Some degree of excessive urinary oxalate is found in 20-30% of all patients with recurrent calcium oxalate stones.

A low-oxalate diet is for people who have calcium oxalate kidney stones is required.

Cutting back on high-oxalate foods and salt (sodium) and drinking plenty of water may help prevent kidney stones from forming.

 

Here are some important points to remember for patients have hyperoxaluria :

• Drink plenty of fluids. Drink more than 8

cups of fluid every day. Your urine should be

as clear as water. If it isn’t, drink more fluids
 
• To prevent oxalate stones from forming,
limit oxalates to 40 to 50 mg per day. Use
the chart as a guide.

• Low-oxalate foods have less than 2 mg of
oxalate per serving. You can eat as much of
these foods as you like.

• Moderate-oxalate foods have 2 to 6 mg
of oxalate per serving. You should eat no
more than three of these foods per day.

• High-oxalate foods have more than 7 mg
of oxalate per serving. Avoid these foods

Most oxalate is a waste product made by the body and

has no function in humans. The most common type of

kidney stone (80%) is made of calcium and oxalate.

Other sources of oxalate include:
• Eating foods high in oxalate
• Intestinal over absorption (patients who have had
intestinal resections due to inflammatory bowel
disease or gastric bypass surgery)
• Excess amounts of vitamin C (2,000 mg or more per
day; the excess converts to oxalate)
• Abnormalities of metabolism

One patient said that his urologist told him to cut back on oxalate. And his cardiologist told him to eat plenty of vegetables and cut back on fats. What you supposed him to do?

One doctor is worried about your heart (diabetes,

hypertension, etc), the other about your kidney stones.
 
If you are going to have a high oxalate food, such as a spinach salad, just limit the amount of spinach you are having.

Also, remember to flush out the extra oxalate you are

eating with a glass of water before and after your meal

Another patient told you that he making calcium oxalate stones. Should he cut back on dairy products too?”

your diet should have between 800 and 1,200 mg of calcium per day.
Eating a diet low in calcium is not advised. In fact,
studies have shown that eating low calcium diets will
increase calcium oxalate stone risk.

Oxalate and calcium bind together in your intestine
and leave the body together. If you eat a low calcium
diet then oxalate has no partner to leave the body
with. Oxalate will then be absorbed back into your
system leading to higher oxalate levels in your body.

What effect does bowel disease and/ or intestinal surgeries with malabsorption have on oxalate levels?”

There is a definite correlation between patients who

suffer from bowel disease and malabsorption problems

and the formation of kidney stones. Their urine is

more acidic, citrate levels are lower, and oxalate levels

are much higher. If you have patient had an ileal resection
your patient may experience an increase in his oxalate levels due to malabsorption problems.

In bowel disease, fatty acids and bile that are normally

absorbed by the small intestine reach the colon.

When fatty acids and bile reach the colon, they can

damage the colon lining allowing oxalate to pass

through the damaged lining into the blood, and then

into the urine via the kidneys. When calcium and

oxalate are together in the kidney, they can bind together to

form crystals. These crystals can join together to form calcium oxalate kidney stones.

How is limiting fat intake will also help lower oxalate level?”
For patients who suffer from small bowel disease or
malabsorption, it is recommended that dietary fat
intake be controlled.
Excess fat will bind with calcium in food, thus leaving oxalate by itself to be reabsorbed by the colon and back into the blood stream. If too much oxalate is absorbed, it will combine with calcium in the kidney and can lead to calcium oxalate stones.

doctor may also prescribe a drug called

Cholestyramine. This is a drug taken at each meal

that binds fatty acids, bile and oxalate so all three

can leave the body.

Does the low oxalate diet cause weight loss?
Foods restricted on the low oxalate diet include certain vegetables, fruits, whole grains, legumes, and nuts.
 
With the exception of nuts, these foods are not calorically dense (i.e., not high in fat). Thus, omitting high-oxalate foods should not necessarily lead to a reduction in caloric intake and subsequent weight loss.

However, there is evidence that some people will

 consume less calories when put on a restrictive

diet. Thus, the degree to which oxalate-containing

foods are restricted could partially dictate whether a

low oxalate diet is lower in calories than a diet not

restricted in oxalate-containing foods.

Does the low oxalate diet cause weight gain?

This would only be true if an individual compensates for

not eating certain fruits and vegetables, whole grains,

and legumes by eating significantly larger quantities than

normal of animal products such as meat, fish, poultry,

eggs, and dairy products. Otherwise, the low oxalate diet

should not lead to weight gain.

Does a low oxalate diet cause constipation?

There may be a possibility of constipation with a

low oxalate diet. Whole grains, legumes, fruits, and

vegetables are the best sources of fiber, an

important dietary component that aids regularity.

Careful selection of foods on a low oxalate diet can

 provide adequate fiber. Any food which provides at least

3 to 4 grams of fiber per serving would be considered an

excellent source (see chart).

To put the numbers in perspective, the recommendation

for total intake of dietary fiber is 25 to 35 grams per day.

I am lactose intolerant. What can I do to increase my
dietary calcium?”

lactose intolerant is a common problem. You get calcium from other sources other than dairy products.

Cereals and orange juice are now fortified with calcium.

Your doctor may also tell you to take
calcium supplements with each meal to help bind

with oxalate so it cannot be reabsorbed back into your
bloodstream.

Because I am lactose intolerant I eat a lot of soy

products. I heard that soy is high in oxalate.”

Recent research has concluded that the soy products

have high levels of oxalate and should be eaten in moderation.

 

 

Facts
• Oxalate is made in plants, animals and humans;
highest amounts appear in certain plant foods.
• The function of oxalate is to help plants dispose
of excess calcium.
• Our bodies have no use for oxalate and it is
excreted in the urine.
• Our bodies always have some varying degree
of oxalate.
• About 40-50% of oxalate is from outside sources
(foods you eat) and can be much higher on a high
oxalate diet.

Low oxalate bioavailability from black tea  
Nutrition Research, Volume 27, Issue 5, May 2007, Pages 273-278 ,Michael Liebman, Shawnna Murphy

Result: 
Both methods suggested that black tea–derived oxalate is of low bioavailability. At the present time, there is little overall support for the recommendation that kidney stone formers limit their intake of black tea

Oxalate content of legumes, nuts, and grain-based flours  
Journal of Food Composition and Analysis, Volume 18, Issue 7, November 2005, Pages 723-729, Weiwen Chai, Michael Liebman

Result :
Total oxalate varied greatly among the legumes tested, ranging from 4 to 80 mg/100 g of cooked weight. The range of total oxalate of the nuts tested was 42–469 mg/100 g. Total oxalate of analyzed flours ranged from 37 to 269 mg/100 g. The overall data suggested that most legumes, nuts, and flours are rich sources of oxalate

EFFECTS OF CALCIUM AND MAGNESIUM ON URINARY OXALATE EXCRETION AFTER OXALATE LOADS  Original Research Article
The Journal of Urology, Volume 163, Issue 5, May 2000, Pages 1565-1569, MICHAEL LIEBMAN, GREGGORY COSTA
 
Results:
Both the calcium carbonate and magnesium oxide treatments were associated with significantly lower load-derived oxalate levels at all time points within the initial 24-hour post-oxalate ingestion period compared with levels observed for the control treatment. There were no treatment effects on endogenous oxalate levels. The efficiency of oxalate absorption for the calcium carbonate (5.1%) and magnesium oxide (7.6%) treatments was significantly lower than that for the control treatment (13.5%).

Effect of supplemental ascorbate and orange juice on urinary oxalate  Original Research Article
Nutrition Research, Volume 17, Issue 3, March 1997, Pages 415-425
Michael Liebman, Weiwen Chai, Ellen Harvey, Laura Boenisch
 
Abstract
The relationship between ascorbate intake, in supplemental form and naturally occurring in orange juice, and urinary oxalate was assessed in 6 healthy individuals. An experimental model which allowed a differentiation between endogenously- and exogenously-derived urinary oxalate was used. Twenty-four hour urine samples were collected the last day of baseline, supplemental ascorbate, and orange juice treatment periods. Oxalate load tests were administered the day following each experimental treatment. Oxalate loads consisted of 175 mg unlabeled and 18 mg 1, 2-¹³C₂ oxalic acid. The orange juice treatment was associated with higher urinary excretion of endogenously-derived oxalate, citrate, and calcium, and a higher urinary pH. Since these urinary changes were not observed during the supplemental ascorbate period, the two sources of ascorbate differentially affected key urinary components which are related to calcium oxalate nephrolithiasis

Olestra and fat inhibit oxalate absorption Original Research Article
Nutrition Research, Volume 19, Issue 9, September 1999, Pages 1277-1285
Michael Liebman, Ellen Harvey, Weiwen Chai

Abstract
An experimental model which allowed a differentiation between endogenously-and exogenously-derived urinary oxalate was used to assess the effect of olestra ingestion on oxalate absorption and excretion. Seventeen healthy subjects participated in three oxalate load (OL) tests separated by at least one week and administered in the following order: OL-1, potato with fat (potato chips); OL-2, potato with olestra (olestra-containing potato chips); and OL-3, potato without fat (boiled potatoes). The three experimental treatments provided similar levels of carbohydrate. Oxalate loads, ingested immediately after consumption of the potato chips/boiled potatoes, consisted of 180 mg unlabeled oxalic acid and 14.3 mg ¹³C₂-oxalic acid. Twenty-four hour urine samples were collected the day before the OL tests and timed urine samples were collected during the 48 h post-oxalate ingestion period. Endogenously-derived oxalate did not differ between treatments. Oxalate absorption for OL-1 (10.5 %) and OL-2 (10.2 %) was lower (P<0.05) than for OL-3 (13.2 %). The presence of fat or olestra depresses total oxalate absor

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