Function:
Although there is some evidence suggesting a beneficial role for these elements in animal and human health, not enough data exists to define with certainty what their specific roles may be.

Recommended Dietary Allowance:
Recommended intake levels have not been established.

Deficiency:
N/A

Sources:
N/A.

Toxicity and UL:
Based on adverse effects noted in animal studies, tolerable upper intake levels (UL) were set for boron at 20 mgs per day; for vanadium at 1.8 mgs per day; and for nickel at 1 mg per day. Arsenic in chemical forms is a known toxic element, but not enough data exists on food and supplements to set a UL. Data also were lacking upon which to base a UL for silicon.

Recommendation:
There is no reason at the present time to supplement these elements.