Is Nickel safe in food and drink?

Soluble nickel salts and nickel carbonyl are classified as reproductive toxicants, and animal studies have reported malformations in offspring following exposure to nickel carbonyl. Exposure to soluble nickel compounds or nickel carbonyl during pregnancy may affect the baby's development and may harm the male reproductive system.

Why here

Systemic absorption of nickel compounds can interfere with reproductive processes and fetal development.

What would have to be true

Exposure to soluble nickel compounds or nickel carbonyl. EFSA's Tolerable Daily Intake (TDI) for nickel from all sources is 13 µg/kg body weight per day, with concerns for young populations exceeding this.

Ingestion of nickel can trigger systemic allergic reactions, such as vesicular hand dermatitis (pompholyx), generalized eczematous reactions, or gastrointestinal symptoms (bloating, diarrhea, abdominal pain) in nickel-sensitized individuals.

Why here

Nickel is naturally present in many foods and can be absorbed from the gastrointestinal tract, leading to systemic exposure in sensitized individuals.

What would have to be true

Dietary intake above certain thresholds (e.g., >150 µg/day for adults, >100 µg/day for children) in nickel-sensitized individuals. Absorption is higher on an empty stomach.

Acute ingestion of large amounts of nickel compounds can cause nausea, vomiting, diarrhea, headache, cough, shortness of breath, and in severe cases, death.

Why here

Direct toxic effects on the gastrointestinal system and systemic absorption leading to other symptoms.

What would have to be true

Ingestion of large amounts, such as 0.5 to 2.5 grams of nickel, or doses significantly higher than typical dietary intake (50,000 to 100,000 times greater than normal food/drinking water levels).

The International Agency for Research on Cancer (IARC) classifies nickel compounds as carcinogenic to humans (Group 1) and elemental nickel as possibly carcinogenic to humans (Group 2B), with some sources mentioning ingestion as an exposure route for carcinogens.

Why here

Systemic absorption of nickel, although the primary concern for carcinogenicity is inhalation.

What would have to be true

Chronic exposure to nickel compounds. The specific ingested dose for carcinogenicity is not well-defined for humans.

The other side

The European Food Safety Authority (EFSA) has concluded that the development of cancers related to the intake of nickel with food is unlikely, with other harmful effects being more often identified.

The European Union restricts the release of nickel from products intended for direct and prolonged skin contact to 0.5 µg/cm²/week, and 0.2 µg/cm²/week for post assemblies inserted into pierced body parts, under the REACH Regulation (Annex XVII, entry 27).

Why here

This regulation applies to various household items such as jewelry, clothing fasteners, and other metal articles that come into prolonged skin contact, aiming to prevent nickel sensitization and allergic contact dermatitis.

What would have to be true

Direct and prolonged skin contact with nickel-releasing articles, with specific migration limits.

Inhalation of certain nickel compounds is classified as carcinogenic to humans (IARC Group 1), and metallic nickel is classified as possibly carcinogenic to humans (IARC Group 2B); however, general population exposure from ambient household air is typically low and not considered to pose an elevated cancer risk compared to occupational settings.

Why here

Nickel compounds can be present in household dust and air, and minimizing exposure to dust is a general recommendation for reducing exposure to various substances.

What would have to be true

Inhalation of nickel compounds and metallic nickel, particularly from dust. While occupational exposure to high levels is the primary concern for cancer, general household exposure to dust containing nickel compounds should be minimized.

Nickel can cause allergic contact dermatitis, an itchy rash, in sensitized individuals upon direct and prolonged skin contact with nickel-releasing household items.

Why here

Many common household items, such as jewelry, clothing fasteners (zippers, snaps, belt buckles), keys, metal tools, kitchen utensils, and electronic devices, contain nickel and are frequently in direct and prolonged contact with the skin.

What would have to be true

Direct and prolonged skin contact with nickel-releasing articles, with regulatory limits in the EU set at 0.5 µg/cm²/week for general products and 0.2 µg/cm²/week for post assemblies inserted into pierced body parts.

Ingesting nickel leached from heated food contact materials can trigger systemic allergic reactions, such as widespread skin rashes, eczema, and gastrointestinal discomfort, in individuals sensitized to nickel.

Why here

Heating acidic foods in nickel-containing food contact materials, particularly stainless steel cookware, can cause nickel to leach into the food, leading to dietary exposure.

What would have to be true

Nickel-sensitized individuals can experience reactions from dietary intake, with studies showing cutaneous reactions in 40-70% of participants after ingesting 0.3mg to 4mg of nickel sulfate hexahydrate. Leaching from stainless steel cookware can contribute up to 88 µg of nickel per 126g serving of acidic food after repeated use, and significantly more (up to 747 µg) from new pans, adding to the total daily dietary intake which typically ranges from 69-350 µg/day. The EFSA tolerable daily intake is 13 µg/kg body weight.

Ingesting high amounts of nickel from food contact materials can cause acute gastrointestinal symptoms such as nausea, vomiting, diarrhea, and stomach pain.

Why here

Nickel can leach from heated food contact materials, especially stainless steel cookware used with acidic foods, increasing the amount of nickel ingested.

What would have to be true

Accidental ingestion of larger doses of nickel (e.g., 0.5 to 2.5 grams) has been shown to cause these symptoms. The EPA also notes that drinking water with high amounts of nickel can cause these symptoms.

Some research suggests that nickel exposure from food contact materials may be linked to metabolic stress and hormonal disruption, potentially worsening conditions like Polycystic Ovary Syndrome (PCOS).

Why here

Nickel can leach from stainless steel cookware into heated food, particularly acidic dishes cooked for long periods or in new pots, contributing to dietary nickel exposure.

What would have to be true

Studies have shown that stainless steel cookware can release up to 88 micrograms of nickel per 126 grams serving of acidic food, which is up to 34 times higher than cooking in a non-reactive pot. This adds to the overall dietary nickel intake.

The other side

There is no direct study proving that stainless steel pots cause PCOS, but rather an association and suggestion that nickel exposure can stress metabolism and hormones.