Nuts/Seeds and nickel: 34 foods rated

Adzuki beans are small and sweet enough to be used in desserts, which is where they catch people out - a red bean paste is a legume portion, and carries the legume nickel with it.

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

Almonds are named in the reference nickel table among the very high foods, alongside the other tree nuts. They are also eaten by the handful and ground into flours, butters and drinks, so the daily total climbs faster than a single portion suggests.

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

Beans are among the legumes named as very high in nickel, which is why they go early on a low-nickel diet. Canning adds a second consideration - the food sits in contact with the can lining for months - but the beans were already high before they went in.

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

Broad beans take nickel up the way every legume does - nickel is the cofactor of urease, the enzyme pulses need for nitrogen, so they draw it from the soil deliberately. Fresh and dried legumes sit together among the highest contents measured.

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

Cashews are high in nickel, and they are also the nut most often blended into sauces, cheeses and creams in plant-based cooking - a cashew cream is a concentrated nut portion, not a garnish.

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

Chickpeas concentrate nickel through the same urease route as every legume, and they are eaten in quantity - a plate of hummus or a curry base is a much larger dose than a garnish.

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

Ground hazelnuts carry exactly the nickel of the whole nut, but disappear into cakes, pralines and biscuit bases where nobody reads them as a nut portion.

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

Hazelnut is one of the nuts named among the very high-nickel foods, and nothing published ranks it against the other tree nuts. If nuts are being reintroduced one at a time, this is the one to leave for last.

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

Lentils are near the top of every low-nickel diet sheet, and for a reason that is built into the plant: nickel is the cofactor of urease, the enzyme legumes need to handle nitrogen, so they take it up from the soil deliberately. Soaking and discarding the water removes a little; it does not change the level.

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

Red beans carry the full legume nickel load. They also need long cooking, and long cooking in a stainless steel pot is the second route worth knowing about - acidic, lengthy cooking draws nickel out of the metal.

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

Red lentils are hulled, which lowers the fibre but not the nickel - the metal sits throughout the seed, not just in the skin. They cook faster than brown lentils and are just as high.

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

Soya beans are the highest-nickel legume measured, and the one hardest to avoid, because they enter the food supply as oil, lecithin, protein isolate and sauce as well as as a bean.

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

Sunflower seeds are high in nickel and turn up as a topping rather than a meal, which makes the dose easy to miss - a seeded loaf or a granola can carry several portions.

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

Walnuts are high in nickel, and unlike most nuts they are usually eaten with the skin, which is the fraction where trace metals concentrate.

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

White beans carry the legume nickel load without the pigment of the coloured varieties, which changes nothing here: the colour is in the skin, the nickel is in the seed.

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

Brazil nuts are famous for selenium, and the same deep-rooted tree takes up nickel and other trace metals with it. Two or three nuts is the usual portion, which is what keeps this moderate rather than high.

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

Macadamia is among the gentler tree nuts on this axis - it is very high in fat, and fat carries almost no metal. What nickel there is sits in the solid fraction.

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

The peanut is a legume that grows underground, so it takes nickel up through the urease route like beans and lentils, and takes it from the soil it sits in. Filed with the nuts on every shelf, it belongs with the pulses here.

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

Pecans carry less nickel than the walnuts they resemble, but they are eaten in pies and pralines where the portion is decided by the recipe rather than by the handful.

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

Chia seeds are eaten whole and soaked, so nothing is removed - but they are used a tablespoon at a time, and the seed is low in nickel to begin with.

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

Flax seed carries a little more nickel than chia, and grinding it - which is necessary to digest it at all - releases what the hull was holding.

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

Hemp seeds are usually sold hulled, and the hull is the fraction that carried the nickel. What is left is the soft kernel, which is mostly protein and oil.

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

Peas are legumes, so they take nickel up through urease like beans - but the green pea is picked immature, before the seed has finished loading. That timing is the whole difference.

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

Pine nuts are seeds rather than true nuts, and they measure lower in nickel than the tree nuts do. They are used a spoonful at a time, in pesto and on salads.

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

Pistachios sit at the bottom of the tree nuts for nickel, well below hazelnut and cashew. They are also eaten shell-on, which slows down how many you get through.

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

Psyllium husk is the seed coat of a plantain, isolated and dried - fibre and little else. It passes through undigested, taking whatever nickel it carried with it.

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

Pumpkin seeds are moderate in most minerals and low in nickel. The hull carries more than the kernel, so hulled seeds measure lower than whole ones.

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

Rapeseed is grown for oil, and oil carries essentially no nickel - it stays with the meal that is pressed out and fed to livestock.

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

Split peas are mature and dried, so they carry more nickel than green peas - the splitting removes the skin, which takes part of it back off again.

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