Fruits and oxalates: 75 foods rated

Aubergine is high in oxalate, and the salting-and-draining step done for bitterness pulls some of the soluble fraction out with the water it draws. Frying does not - oil takes nothing water-soluble with it, and an aubergine absorbs a great deal of oil.

• Chai W & Liebman M, J Agric Food Chem 53 (2005), 3027-3030, which measured 30-87 % loss of soluble oxalate on boiling against 5-53 % on steaming
• Noonan SC & Savage GP, Asia Pac J Clin Nutr 8 (1999)

Goji berries are high in oxalate and eaten dried, which means concentrated - and they are marketed as a daily addition to porridge and smoothies rather than as an occasional fruit. Daily and dried is the combination that matters on an axis that accumulates.

• Noonan SC & Savage GP, Asia Pac J Clin Nutr 8 (1999)
• USDA FoodData Central

Pomegranate is high in oxalate, and the juice concentrates it - a glass is several fruits, pressed. The arils eaten by the spoonful from a whole fruit are a much smaller dose than the same fruit drunk.

• Noonan SC & Savage GP, Asia Pac J Clin Nutr 8 (1999)
• USDA FoodData Central

Rhubarb is the food this axis was written for. The stalks are among the highest oxalate foods measured, and the leaves carry enough to be genuinely poisonous - which is why they are never sold. Stewing in water and pouring some of it away removes part of the soluble fraction; eating it with cream or custard does more, because the calcium binds the oxalate in the gut before it can be absorbed.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8 (1999) 64–74: mean oxalate intake 70–150 mg a day in English diets, tea the largest single contributor, and soaking or cooking reduces oxalate by leaching

Blackcurrant is moderate as a fresh berry and rarely eaten that way - it arrives as coulis, syrup or jam, each of which is many berries in a spoonful. The sugar changes nothing about the oxalate; the concentration changes everything.

• Noonan SC & Savage GP, Asia Pac J Clin Nutr 8 (1999)
• USDA FoodData Central

A blood orange is a sweet orange - a cultivar of Citrus sinensis, not another fruit - so it carries what an orange carries. What is genuinely particular to it is the anthocyanin that colours the flesh, and anthocyanins do not remove oxalate.

• Swain A et al., Friendly Food (RPAH elimination diet)
• USDA FoodData Central

Orange is a moderate oxalate source, so if you are sensitive keep the portion reasonable and drink plenty of water to help clear oxalate. Dried and concentrated forms are higher.

Sun-dried tomato concentrates a fruit that is low in oxalate when fresh - drying multiplies everything, including the things that were small. It is eaten in slivers, which is what keeps the dose moderate rather than high.

• Noonan SC & Savage GP, Asia Pac J Clin Nutr 8 (1999)
• USDA FoodData Central

Apricot is low in oxalate, fresh. The form this axis is usually asked about is the dried one, and it has its own row here, because drying changes the arithmetic per hundred grams.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Canned apricots are low in oxalate, and the tin means the fruit was peeled and cooked before it was packed. Between the fresh apricot and the dried one, both with their own rows, the canned fruit is the middle form and the answer does not change.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Banana is low in oxalate. Ripeness changes its sweetness, not this answer, and the portion never changes either: it is the one fruit sold and eaten by the unit.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Bell pepper is low in oxalate, and the usual preparation trims it further: the seeds and the white ribs - the parts a plant loads first - are cut away, and what goes in the pan is flesh. Raw, roasted or stuffed, this axis has little to say about it.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

No published assay of oxalate reaches the chokeberry, and it is eaten whole with its seeds, which is where a berry keeps that compound. It is almost never eaten fresh — the astringency sends it to juice, powder and dried fruit, and each of those is many berries at once.

Cranberry is low in oxalate as a fruit, but almost nobody eats it as a fruit: it arrives as juice, as sauce, or dried and sweetened, and each form is a different serving. The dried berries keep company with raisins, the juice with drinks - the question follows the form.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Dates are low in oxalate, and a date is dried fruit by nature: the water left on the palm, so each one is already the concentrated form of itself. Two or three make a serving, and that small unit is what keeps the total low.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Dried apricots are low in oxalate, but drying changed the arithmetic: the water is gone and everything else stayed, so a hundred grams of these is several fresh apricots. The handful, not the fruit, is the serving to count.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Dried figs are low in oxalate, with two things working in opposite directions: drying concentrates, as for every fruit, and a fig is eaten with its hundreds of tiny seeds - the part a plant loads first. The serving stays a few figs, and that is what keeps the total low.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Dried peach is low in oxalate, concentrated by drying like any dried fruit: what was a whole peach is now a strip, and a hundred grams of strips is several peaches. Count the strips, not the peaches they were.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

No published assay of oxalate reaches the elderberry, and it is eaten whole with its seeds, which is where a berry keeps that compound. It is never eaten raw either — it arrives cooked, as syrup or cordial, and the cooking water is not thrown away here: it becomes the syrup, with whatever soluble oxalate it drew out.

Guava is low in oxalate, and it is eaten whole - peel, flesh and the hard little seeds, which are exactly where a plant stores this compound. Even so the serving is one fruit, and one fruit is a small dose.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Berries are not among the foods the oxalate literature flags, but the lingonberry is absent from the published tables.

No published oxalate table reaches the longan, and its close relative the lychee is not measured either.

Mulberry is low in oxalate, like most fruit. Fresh it is a short-season fruit; the rest of the year it arrives dried or as jam, and dried means the water left and everything else stayed - a handful of dried mulberries is several times the fruit it looks like.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Passion fruit is low in oxalate, and it is one of the rare fruits whose seeds are eaten - the very place a plant concentrates this compound. What saves the serving is size: a spoonful of pulp and seeds, not a bowl.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Pear is low in oxalate, eaten peel and all - and the peel is not where this axis points. A soft ripe pear and a firm cooking pear give the same answer here.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Persimmon is low in oxalate, and it is eaten at the ripe end of ripe, when the astringency has gone and the flesh is almost jelly. Unripe it punishes the mouth; ripe it is a dessert - and this axis gives the same low answer to both.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Plantain is low in oxalate, and it is never eaten raw: boiled, fried or baked, it is cooked like a potato and eaten as a staple, not as a dessert fruit. At any ripeness the answer is the same low.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

No published oxalate table reaches the rose hip, common as it is in tea.

Sultanas are low in oxalate, and they are a dried grape eaten like a condiment - scattered into baking, muesli or a tagine, rarely eaten alone. The small scatter is the serving, and it keeps the total low.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans

Tamarind is low in oxalate, and the form matters more than the fruit: it is used as a paste or a concentrate, spoonfuls of sourness stirred into a whole pot, never eaten by the pod. Even a strong jar doses a dish, not a person.

• Noonan S.C. & Savage G.P., Asia Pac J Clin Nutr 8:1 (1999) 64-74, oxalate content of foods and its effect on humans