Studying does have its advantages.  I found the mainstream medical
reccommendations about vitamin and mineral supplementation in
bf babies.
1 -Subcommittee on Nutrition During Lactation, Committee on
Nutritional Status During Pregnancy and Lactation, Food and Nutrition
Board, Institute of Medicine, National Academy of Sciences (!) 1991
--All newborns should receive a 0.5 - 1.0 mg oral dose of
vit k immediately after birth
--The infant should be given a 5 -7 microgram supplement of vitD
per day if exposure to sunlight appears inadequate
--Fluoride supplements should be provided only to breastfed
infants who live in households in which the fluoride in the water
islow <0.3 ppm
--Human milk is a sufficient souce of iron for the first
6 months
--The milk of complete vegetarians (no eggs, dairy) is likely to be
deficient in B12.  Supplement infant OR mother


Vitamin and mineral supplement needs in normal children in the US
AAP - Committee on Nutrition (1980) Quoted in Ruth Lawrence - appendix K
Info is essentially similar to above - chart shows no need for routine
vitamin/mineral supplements in breastfed infants even after 6 mo. with
the possible exception of iron.

"The supplementation of fluoride in the diet of a healthy breastfed
infant is no longer recommended by the American Academy of Pediatrics.
Evidence supports the contention that there is adequate fluoride
in human milk, and fluoride from excessive amounts is a concern."
"The committee on nutrition stated in 1986 "It may not be
necessary to give fluoride supplements to breastfed infants who
are living in an area that is adequately fluoridated"
(Lawrence p. 815)

I still would like to find studies on later need for iron. I will
keep looking.  Over the years I have suggested to mothers who
would prefer not to introduce solids for various reasons to
ask for hematocrit or other blood work before starting.  I know
this is considered invasive by some but it is often preferable,
depending on the situation.