These three trace minerals share a shape: your body needs very little of each, and the gap between the recommended intake and the published upper limit is narrower than it is for most nutrients.
That combination is why the upper limits below are worth as much attention as the intakes.
The source matters more than for most minerals. The same milligram of zinc from whole grains and from meat does not reach you in the same amount, which changes what a plant-based eater is working with.
The zinc RDA for women is 8 mg/day, increasing to 11 mg in pregnancy and 12 mg while breastfeeding.
A health authority states this in its published guidance.
RDA table: 19+ years — Female 8 mg, Pregnancy 11 mg, Lactation 12 mg
Plant sources of zinc such as whole grains have lower mineral bioavailability than animal sources.
More than one independent health authority states this.
"Beans, nuts, and whole grains contain zinc, but the bioavailability of zinc from these foods is lower than that from animal foods because these foods contain phytates."
Source: NIH Office of Dietary Supplements and FAO (WHO/FAO joint publication)
Closer than people expect. The recommended intake and the upper limit sit in the same order of magnitude, which is unusual, and it is the reason selenium supplements deserve a second look rather than a casual one.
The selenium RDA for women is 55 mcg/day, rising to about 60 mcg in pregnancy and about 70 mcg when lactating.
A health authority states this in its published guidance.
RDA: 19–50 years — 55 mcg (women), Pregnancy 60 mcg, Lactation 70 mcg
The Tolerable Upper Intake Level for selenium is 400 mcg per day.
A health authority states this in its published guidance.
The Tolerable Upper Intake Level (UL) for adults is set at 400 µg (5.1 µmol)/day based on selenosis as the adverse effect.
Source: NIH National Library of Medicine
Selenoproteins help make DNA and act as antioxidants that protect against cell damage and infections.
A health authority states this in its published guidance.
"selenoproteins play critical roles in thyroid hormone metabolism, DNA synthesis, reproduction, and protection from oxidative damage and infection."
People with kidney failure or HIV and those on primarily plant-based diets are at higher risk for selenium deficiency.
A health authority states this in its published guidance.
At-risk groups include people undergoing kidney dialysis, people with HIV, and those following a "vegetarian or vegan dietary pattern."
Almost certainly not, and the reason is worth knowing. There is no RDA for manganese at all, deficiency is very rare where food is plentiful, and the documented toxicity cases came from water and air rather than from meals.
There is no RDA for manganese; the Adequate Intake is 1.8 mg/day for adult women, 2 mg for pregnant women, and 2.6 mg for breastfeeding women.
A health authority states this in its published guidance.
AI: 19–50 years — 1.8 mg (women), Pregnancy 2.0 mg, Lactation 2.6 mg (Adequate Intakes; no RDA established)
The daily upper limit for manganese is 11 mg for women, including those pregnant or breastfeeding.
A health authority states this in its published guidance.
Adults 11 mg ... Pregnant and breastfeeding teens 9 mg; Pregnant and breastfeeding women 11 mg
Manganese deficiency is very rare in the US; symptoms include skin rashes, loss of hair color in men, mood changes, and worse premenstrual pain than normal.
A health authority states this in its published guidance.
"Manganese deficiency is very rare in the United States." Symptoms: "Skin rashes and loss of hair color in men; Mood changes and worse premenstrual pain than normal in women."
Studies show no harm from manganese in food; toxicity has been reported from high-manganese water and inhaled manganese dust (welding/mining).
A health authority states this in its published guidance.
"Studies have not shown any harm from the manganese in food and beverages." Toxicity reported from "consuming water containing very high levels of manganese" and "inhaling large amounts of manganese dust from welding or mining work."
From food you probably already eat. One of these is a single handful.
Listed foods (shellfish, whole grains, nuts, spices, etc.) contain a good dose of manganese.
A health authority states this in its published guidance.
Shellfish sources: mussels, oysters, clams. Nuts, especially hazelnuts and pecans. Whole grains: brown rice, oatmeal. Spices: black pepper. 'The main food sources of manganese in the U.S. diet are tea, vegetables, and whole grains.'
A serving of hazelnuts contains about 1.7 mg of manganese.
A health authority states this in its published guidance.
Hazelnuts, dry roasted, 1 ounce | 1.6 | 70