Zinc is an essential mineral.
Roles in the Body
The adult body contains about 2 g of zinc, mainly in muscle and bone. Zinc is a component of hundreds of enzymes and is needed to make proteins and DNA. It is also involved in taste cells and immune responses.
Deficiency can cause reduced sense of taste, dermatitis and delayed growth.
Source：[1]
Recommended Intake and Upper Limit
Recommended daily intake and tolerable upper intake level for adults, from the Dietary Reference Intakes for Japanese (2025).
| Men | RDA | Upper limit |
|---|---|---|
| 18–29 | 9.0 | 40 |
| 30–49 | 9.5 | 45 |
| 50–64 | 9.5 | 45 |
| 65–74 | 9.0 | 45 |
| 75+ | 9.0 | 40 |
| Women | RDA | Upper limit |
|---|---|---|
| 18–29 | 7.5 | 35 |
| 30–49 | 8.0 | 35 |
| 50–64 | 8.0 | 35 |
| 65–74 | 7.5 | 35 |
| 75+ | 7.0 | 35 |
mg/day. +2.0 mg in mid/late pregnancy, +3.0 mg while breastfeeding.
Actual Intake in Japan
In the 2023 National Health and Nutrition Survey, average daily zinc intake for adults was 9.0 mg for men and 7.6 mg for women.
| Age 20+ | Actual intake (mean) | RDA (age 30–64) |
|---|---|---|
| Men | 9.0 mg | 9.5 mg |
| Women | 7.6 mg | 8.0 mg |
Foods Rich in Zinc
Seafood, meat, nuts and seeds, and dairy are good sources.
Zinc content of foods
mg per 100 g edible portion
What Hinders Absorption
Zinc absorption is generally estimated at about 30%. Dietary fiber, phytic acid in grains and beans, and some food additives hinder absorption, and alcohol increases zinc excretion.
Source：[1]
Zinc in Older Adults
Daily zinc intake by age shows that, among men, intake decreases with age.
| Age | Men | Women |
|---|---|---|
| 40s | 9.4 | 7.6 |
| 50s | 9.1 | 7.7 |
| 60s | 9.2 | 7.6 |
| 70s | 8.7 | 7.5 |
| 80+ | 8.2 | 7.4 |
mg/day (mean). National Health and Nutrition Survey 2023.
The Japanese Society of Clinical Nutrition’s 2018 guideline states that many older adults are zinc deficient. At seven clinics in Nagano, about 25% of older patients had serum zinc below 65 μg/dL; in a Nagano town health check (1,009 people), 37.9% of those aged 60+ were below 65 μg/dL.
Older adults with low serum zinc (<66 μg/dL)
Report cited in the JSCN guideline
The guideline lists low intake, reduced digestion and absorption, lifestyle diseases and medications as causes of zinc deficiency in older adults.
Studies on Low Zinc and Illness
The guideline notes that zinc-deficient older patients in long-term hospital care are more prone to infections.
| Study (subjects) | Findings |
|---|---|
| USA (2007) 578 nursing home residents | About 30% had low serum zinc; those with normal zinc had about half as many pneumonia episodes. |
| Japan (2024) 13,100 people, national claims data | Zinc deficiency was more common in older adults, men and inpatients, and was associated with aspiration pneumonia (about 3.0×), pressure ulcers (about 2.4×) and sarcopenia (about 2.2×). |
Both are observational studies; whether low zinc causes these conditions is not known.
COVID-19, Long COVID and Blood Zinc Levels
Several studies have measured blood zinc levels in people hospitalized with COVID-19. All are observational, and it is not known whether low zinc causes more severe illness.
Share of patients with low blood zinc (<70 μg/dL)
29 inpatients, Sakai City Medical Center, Japan (2020)
| Study (subjects) | Findings |
|---|---|
| Japan (2020) 29 inpatients | Low zinc in 6 of 7 critical patients and 3 of 22 mild/moderate patients. |
| Japan (2024) 60 patients early in infection | Patients with blood zinc below 60 μg/dL more often developed pneumonia requiring oxygen. |
| India (2020) 47 patients, 45 healthy controls | Median zinc 74.5 μg/dL in patients vs 105.8 μg/dL in controls; 57% of patients were zinc deficient. |
| Meta-analysis of 20 studies (2023) 2,319 people | More severe cases tended to have lower blood zinc. |
Long COVID and Blood Zinc Levels
At the long COVID clinic of Okayama University Hospital, 43 of 194 patients (22.2%) had low blood zinc (<70 μg/dL). The most common symptom among them was general fatigue, and those with very low zinc (<60 μg/dL) more often reported smell or taste problems. This was a single-hospital study without a healthy comparison group.
In a study from Iraq, blood zinc did not differ between 60 people with long COVID and 30 who recovered without it (although zinc tended to be lower the longer symptoms lasted).
Cautions on Excess
Excess intake from ordinary meals is unlikely, but taking high doses of zinc daily from supplements can block copper absorption and cause copper deficiency, anemia and stomach upset.
Source：[1]
Related Ingredients
Sources
- [1]Kenko Choju Net (Japan Foundation for Aging and Health), "Zinc"
https://www.tyojyu.or.jp/net/kenkou-tyoju/eiyouso/mineral-zn-cu.html - [2]Ministry of Health, Labour and Welfare, Dietary Reference Intakes for Japanese (2025)
https://www.mhlw.go.jp/content/10904750/001207481.pdf - [3]MHLW, National Health and Nutrition Survey 2023
https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/kenkou_iryou/kenkou/eiyou/r5-houkoku_00001.html - [4]MEXT, Standard Tables of Food Composition in Japan (8th ed., 2023)
https://fooddb.mext.go.jp/ - [5]MHLW, National Health and Nutrition Survey 2023, Part 1 Table 1
https://www.mhlw.go.jp/content/001435373.pdf - [6]Japanese Society of Clinical Nutrition, Clinical Practice Guideline for Zinc Deficiency 2018
https://www.jscn.gr.jp/pdf/aen2018.pdf - [7]Kogirima M, et al. Eur J Clin Nutr 2007;61(3):375-381
https://pubmed.ncbi.nlm.nih.gov/16969379/ - [8]Meydani SN, et al. Am J Clin Nutr 2007;86(4):1167-1173
https://pubmed.ncbi.nlm.nih.gov/17921398/ - [9]Yokokawa H, et al. Sci Rep 2024;14:2791
https://pubmed.ncbi.nlm.nih.gov/38307882/ - [10]Yasui Y, et al. Int J Infect Dis 2020;100:230-236
https://pubmed.ncbi.nlm.nih.gov/32911042/ - [11]Fujita K, et al. J Infect Chemother 2024;30(10):978-982
https://pubmed.ncbi.nlm.nih.gov/38460615/ - [12]Jothimani D, et al. Int J Infect Dis 2020;100:343-349
https://pubmed.ncbi.nlm.nih.gov/32920234/ - [13]Fan L, et al. Biometals 2023;36(5):929-941 (meta-analysis)
https://pubmed.ncbi.nlm.nih.gov/37079168/ - [14]Matsuda Y, et al. (Okayama University Hospital) J Clin Med 2023;12(5):2062
https://pubmed.ncbi.nlm.nih.gov/36902849/ - [15]Masoodi WTA, et al. Am J Med Sci 2026;371(3):259-266
https://pubmed.ncbi.nlm.nih.gov/41130564/
This page provides general information about the ingredient and does not indicate the effects or efficacy of any product.