Cadmium in food

Forms

• In food assessments, cadmium is not divided into forms the way mercury and arsenic are; it is measured as total cadmium.
• Once in the body, it is slow to leave. The half-life in the kidney is 12–23 years (estimated), and JECFA gives about 15 years. For this reason JECFA expresses its tolerable level per month rather than per week.
• Only a small fraction is absorbed: The retention rate in the human body is 2–8% (FSCJ). It has been reported that absorption increases when iron is deficient.
• Concentrations in food differ by orders of magnitude by part. This database lists muscle (the edible portion) and innards separately. The unit is mg/kg (= ppm).

Foods with cadmium data

Sorted by mean, highest first. Values in different forms (total vs inorganic, dried vs soaked) cannot be compared directly — check each food page.

Effects on the body

• Long-term intake lowers the reabsorption function of the proximal tubules in the kidney. The marker is an increase in urinary β2-microglobulin (the FSCJ used 1,000 μg/g creatinine as the cutoff).
• Effects on bone: Through kidney damage, severe cases lead to osteomalacia. On the other hand, overseas it has been pointed out that even at low concentrations, osteoporosis and fractures may increase without going through the kidney (France’s ANSES 2017 focused on a Swedish study in which fractures increased at a urinary level of 0.5 μg/g creatinine or more). The FSCJ does not use bone as an endpoint in its assessment because there is no Japanese data.
• IARC (2012) classified cadmium and its compounds in Group 1 (lung cancer). For the low amounts that come from food, the FSCJ writes that the evidence for increased risk is insufficient.
• Smoking: The Consumer Affairs Agency estimates that one cigarette contains 1–2 μg, about 10% of it reaches the lungs and about 50% of that is absorbed, so smoking 20 cigarettes a day absorbs about 1–2 μg/day. In Chiba Prefecture (an uncontaminated area), blood concentrations in men aged 50 and over were 1.5 ng/g in nonsmokers and 2.2 ng/g in smokers.
• Routes other than diet are small: In an estimate by the Environment Agency (2000), diet was 99.9% (air 0.05%, drinking water 0.03%, soil 0.005%).
• Official view: The FSCJ says that cadmium intake from food by the typical Japanese person is unlikely to have adverse effects on health. Eating rice that exceeds the standard for a short period is also said to be unlikely to have adverse effects (the standard is a long-term average).

Tolerable intake (the amount thought to cause no harm even if taken for a lifetime)

How much people in Japan take in

• Trend in intake (total diet study): from about 46 in the late 1970s to 22.3 in 2005, 18.1 in 2016, 17.7 in 2020, and 15.9 μg/person/day in fiscal 2023. Decade averages are 31.3 (1981–90) → 28.1 → 23.1 → 19.3 (2011–20).
• In 2022 it was 2.03 μg/kg body weight/week (about 16 μg/day), which is about 30% of the FSCJ value of 7. In 2024 it was 13.4 μg/person/day (0.24 μg/kg/day per body weight).
• Putting the same 2022 value against three yardsticks, it is 29% of the FSCJ value of 7, 35% of JECFA (about 5.8 converted to a week), and 81% of EFSA’s 2.5 (Urayomi’s calculation, body weight 55.1 kg). The question is not which is correct; the bases differ (Japanese epidemiology versus a theoretical model from urinary concentrations).
• Foods that contribute most: In 2022, rice and its processed products were 34.1% and other vegetables and seaweed were 20.5%. In 2024, rice was 34.2%. In MAFF’s estimate (2016), about 46% of intake from agricultural products was rice, 17% wheat, and 11% soybeans. Because the way of measuring (agricultural products only versus all foods, and the year) differs, we read it as a range: “rice is about 30–50%.”
• Distribution among high consumers: In MAFF’s probabilistic estimate (2016), intake from all foods averaged 2.4 and the 95th percentile was 4.7 μg/kg/week, which are 35% and 67% of the TWI of 7. These cannot be lined up with surveys that use different estimation methods (for example, the National Institute for Environmental Studies mean of 3.44 and 95th percentile of 7.18).
• The contribution of rice has decreased: In 1981–90 rice was 14.6 μg/day (about 47% of the total), and in 2011–20 it was 7.1 (about 37%). Of the total decrease of 12.0 μg/day, 7.5 (62%) was due to the decrease in rice (Urayomi’s calculation).

History

• October 1955: A “strange disease” in the Jinzu River basin in Toyama Prefecture was reported to the Clinical Surgery Society as being of unknown cause (itai-itai disease).
• May 1968: The Ministry of Health and Welfare announced its view. It was chronic cadmium poisoning, in which kidney damage occurs first and then osteomalacia; predisposing factors include pregnancy, lactation, endocrine disturbance, aging, and deficiency of calcium and other nutrients; and no cause could be found other than the wastewater from the Kamioka mine of Mitsui Mining & Smelting.
• 1970: A standard of less than 1.0 ppm for brown rice was set (0.9 for polished rice). Rice of 0.4 or more and less than 1.0 was purchased by the government and not used as food. In 1971, the designation requirement under the Agricultural Land Soil Contamination Prevention Act was set at “rice of 1 mg/kg or more,” and in June 2010 it was revised to “more than 0.4 mg/kg.”
• Certification: The last certification of itai-itai disease was in October 1974, and the number of certified patients was 57 at the end of March 1977 (White Paper on the Environment).
• July 2008: The FSCJ set a TWI of 7. In April 2010 the MHLW revised the standard to 0.4 ppm or less for brown and polished rice, which took effect at the end of February 2011.
• 2010: JECFA withdrew the old PTWI and set a PTMI of 25. 2012: IARC classified cadmium in Group 1.
• 2015: NARO registered the low-absorption variety “Koshihikari-Kan 1” (a mutation obtained with a heavy ion beam; cadmium in the brown rice is extremely low).
• June 2024: MAFF drew up guidelines to reduce both cadmium and arsenic.

Good to know

• Japan’s legal standards exist only for rice (0.4 mg/kg in brown and polished rice) and for mineral waters (0.003 mg/L). The Consumer Affairs Agency explains that for foods other than rice, intake is small and setting a standard would bring little reduction, so it does not set standards and responds with measures at the production stage and with surveys of actual conditions. The rice standard is the same as Codex (0.4), and the EU’s is 0.15.
• Milling, washing, and cooking rice barely reduce cadmium. The concentration of polished rice, taking brown rice as 100, averages 95% (rice harvested in fiscal 2022–24), so the reduction is 2–5%. MAFF summarizes that rice bran is higher than brown rice.
• Not eating the innards of seafood, or limiting the amount, is the most effective step in terms of concentration, but the public agencies do not say “don’t eat them.” The Consumer Affairs Agency says to be careful about bias from continuing to eat large amounts of the same food every day, and to keep a balanced diet.
• We could not find public data on how much cadmium is reduced by cooking (such as soaking then boiling in fresh water (yudekoboshi)). We have also found no public concentration data in Japan for seaweed, hijiki, liver, kidney, or sunflower seeds.
• Rice from fiscal 2022–24 and from fiscal 2009–10 have different limits of quantification (0.01 and 0.04). The change in the “average from 0.05 to 0.04” compares surveys with different detection power, so the trend is better read from the distribution (the share at 0.1 or below went from 91.0% to 96.0%).
• It cannot be said that “eating cadmium rice causes itai-itai disease.” The Consumer Affairs Agency says that it occurred when predisposing factors such as pregnancy, lactation, aging, and poor nutrition were present on top of long-term intake of high concentrations, and that onset from intake at low concentrations is not conceivable. On the other hand, the debate continues over whether low concentrations over a long period affect kidney function and bone. We write both.

Related explainers

• Arsenic and Cadmium in Brown and White Rice: Is Eating It Every Day OK? Measurements of Japanese Rice and How to Reduce Them
• Why Do Heavy Metal Standards Differ Between Japan and Other Countries? Japanese, Codex, and EU Standards and Tolerable Intakes Compared
• How Much Heavy Metal Do Japanese People Take In? Fifty Years of Lead, Cadmium, Mercury, and Arsenic Intake
• Can Home Cooking Reduce Heavy Metals? Figures Shown for Hijiki, Rice, Innards, Tap Water, and Canned Food
• Heavy Metals in Baby Food, Infant Food, and Powdered Formula: MAFF’s Survey and Standards Abroad

Sources

• MAFF, survey of cadmium and arsenic in rice harvested in fiscal 2022–24 (December 19, 2025)
• MAFF, actual cadmium concentrations in domestic agricultural products (fiscal 2009–14)
• MAFF, cadmium standards (Japan)
• Consumer Affairs Agency, “Q&A on cadmium in food”
• FSCJ, assessment of cadmium (summary version)
• JECFA database (cadmium)
• Ministry of the Environment, White Paper on the Environment (1977), itai-itai disease
• EFSA, “EFSA sets lower tolerable intake level for cadmium in food”

Last checked 2026.10.03 (against the original government documents and papers, collected and cross-checked in Gemini Notebook).

Pages for each metal

• Mercury
• Arsenic
• Lead