Fruits and nickel: 75 foods rated

Coconut is high in nickel, which surprises people who file it with the tropical fruit rather than with the nuts and seeds. The palm draws the metal up through sandy coastal soil. Coconut is one of the few plant foods measured for this axis in its own right: the level follows a survey of essential and non-essential metals across COCONUT PRODUCTS, which is why the water, the flesh and the milk do not all read the same here.

• Ahmed M. et al., J Food Compos Anal 127 (2024) 105943, essential and non-essential metals in coconut products

Blackcurrant carries more nickel than most berries. The bush takes up trace metals readily, and the fruit is usually eaten concentrated - as a coulis, a syrup or a jam rather than by the handful. No measurement of blackcurrant nickel is published: what is known is what the bush takes up, not a figure from a table.

Dried figs concentrate what the fresh fruit held, and figs hold more than most - the seeds and skin are eaten with the flesh, and that is where the metal sits. Drying is the whole question for nickel: water leaves and everything else stays, so a dried fruit carries the metal concentrated by weight. The level here follows a study of trace elements in DRIED fruit for that reason.

• Duran A. et al., Int J Food Sci Nutr 59:7-8 (2008) 581-589, trace elements in dried fruit

Dried peach concentrates the fresh fruit several times over as the water leaves. The peach was low to begin with, which is why this lands at moderate rather than higher. Drying is the whole question for nickel: water leaves and everything else stays, so a dried fruit carries the metal concentrated by weight. The level here follows a study of trace elements in DRIED fruit for that reason.

• Duran A. et al., Int J Food Sci Nutr 59:7-8 (2008) 581-589, trace elements in dried fruit

Pineapple is one of the few fresh fruits with a measurable nickel load - the plant grows in acidic tropical soil, which mobilises metals that neutral soil holds onto. Canned pineapple adds a second source, because the tin itself leaches nickel into what it holds. No published assay covers the fruit; what is known is the soil the plant grows in.

Canned foods leach nickel from the tin, and canned apricot is one. Smart and Sherlock measured it: canned vegetables were one of the three highest nickel groups in the UK diet, which the authors attribute to processing equipment and possibly the cans themselves. They measured canned VEGETABLES and not canned fruit, and they report group figures rather than product ones. The fresh apricot is the lower form.

• Smart G.A. & Sherlock J.C., Food Addit Contam 4 (1987) 61-71, nickel in foods and the diet

Blood orange: fruit sits low on the nickel axis as a rule, and citrus with it: the metal comes up from the soil and concentrates in seeds, nuts and whole grains rather than in a fleshy fruit. Canned is the version to watch on this axis and not only here - acidic contents in a tin pull metal from the can, which is why tinned citrus is a different answer from a fresh one. Flyvholm's review is where that list comes from — cocoa, soya, oatmeal, nuts and legumes are the high-nickel foods, and no fruit is among them. It publishes no figure for any single food, so the tin is a general caution here rather than a measured one.

• Flyvholm M.-A. et al., Z Lebensm Unters Forsch 179 (1984) 427-431, nickel content of food and estimates of dietary intake

Cranberries grow in acidic bogs, which mobilises metals - yet they still measure low, because the fruit itself takes up very little. Dried sweetened cranberries concentrate what there is. No measurement of cranberry nickel is published: the berry study behind this axis covers lingonberry, blueberry and rose hip, and the lingonberry is a different Vaccinium from the cranberry.

Prunes concentrate the plum by removing its water, and a plum is a low-nickel fruit - so even concentrated it stays here. Drying is the whole question for nickel: water leaves and everything else stays, so a dried fruit carries the metal concentrated by weight. The level here follows a study of trace elements in DRIED fruit for that reason.

• Duran A. et al., Int J Food Sci Nutr 59:7-8 (2008) 581-589, trace elements in dried fruit

Fresh figs are low, though the seeds and skin are eaten whole and that is where a fruit keeps its nickel. Dried figs sit a level higher for exactly that reason.

Jujube is one of the two fruits Nie found highest in nickel among China's five main deciduous crops, the other being the peach. No figure is published for it: the study gives an order, not values, and its own conclusion is that all five are safe to eat, the five together supplying no more than 1.1 per cent of the tolerable daily intake. Being at the top of a short list whose bottom is also low is what this level reflects.

• Nie J. et al., J Integr Agric 15:7 (2016) 1645-1655, heavy metals in the main deciduous fruits

The dried longan is where a nickel figure would matter, since drying concentrates metals by weight, and no published survey reaches this fruit.

Nectarines measure like peaches here, low, and the missing fuzz makes no difference to the nickel. Ripeness does not change it either. Nie measured peach among five Chinese deciduous fruits, and a nectarine is the same species; the five together came to no more than 1.1 per cent of the tolerable daily intake.

• Nie J. et al., J Integr Agric 15:7 (2016) 1645-1655, heavy metals in the main deciduous fruits

Oranges are low in nickel, and the peel carries more than the flesh - which matters only if you use zest. Juice is lower still, since it leaves the pith behind.

Peaches are low in nickel, unlike their sorbitol, which is high - the two axes have nothing to do with each other. Dried peach is a different matter, since drying concentrates. Nie measured five Chinese deciduous fruits — apple, pear, peach, grape and jujube — and put peach among the higher of them, though the whole set came to no more than 1.1 per cent of the tolerable daily intake.

• Nie J. et al., J Integr Agric 15:7 (2016) 1645-1655, heavy metals in the main deciduous fruits

Persimmon is low in nickel. It grows on trees with deep roots, which reach subsoil rather than the topsoil where most agricultural metal accumulates.

Rose hip is the exception in the study that measured it. Lingonberries and blueberries came out clear on cadmium, chromium and nickel; rose hips separately carried LEAD beyond the limit set for fruit and ALUMINIUM at 8 mg/g. That is not nickel, and no nickel figure of its own is published for the rose hip — but a fruit that accumulates two other metals is not one to call clear. The samples came from an unpolluted area, which makes the finding harder rather than easier to dismiss.

• Zeiner M. & Juranović Cindrić I., Toxics 6 (2018) 31, Al, Cd, Cr, Ni and Pb measured in lingonberries, blueberries and rose hips

Sun-dried tomatoes concentrate the fruit several times over, and tomatoes take up rather more from soil than most fruits do. They stay low because they are eaten in slivers, not by the bowl. Drying is the whole question for nickel: water leaves and everything else stays, so a dried fruit carries the metal concentrated by weight. The level here follows a study of trace elements in DRIED fruit for that reason.

• Duran A. et al., Int J Food Sci Nutr 59:7-8 (2008) 581-589, trace elements in dried fruit

Tamarind is a pod pulp, sour enough to be used as an acidulant - and acid is the thing that pulls metal out of a pan. The fruit is low; what it is cooked in matters more than what it is. Drying is the whole question for nickel: water leaves and everything else stays, so a dried fruit carries the metal concentrated by weight. The level here follows a study of trace elements in DRIED fruit for that reason.

• Duran A. et al., Int J Food Sci Nutr 59:7-8 (2008) 581-589, trace elements in dried fruit