Selenium
SeToday
7-day average. Days to weeks of reserve, so single days mean little.
What it is
Builds the enzymes that recycle antioxidants and activate thyroid hormone.
Reference intake
Your daily target, personalised to your age and sex.
- RDA
- 55 mcgmale_19_plus
- Upper limit
- 400 mcgapplies to total
One of the narrowest margins between requirement and excess of any nutrient: the RDA is 55 mcg and the limit is 400. A few Brazil nuts a day can reach it, since a single nut carries 68 to 91 mcg.
Full write-up not finished
The reference intake above is real and cited — Selenium is assessed against it exactly like any other nutrient. What is missing is the written panel: what it does in detail, what deficiency and excess look like, absorption, interactions, and food sources ranked against what you eat.
Entries live in data/nutrients.json. Filling this one in changes no code.
Sources
Last reviewed 2026-08-11