Boron (B) is a trace mineral that is essential for plants. Boron may
also be essential for humans and animals based on recent experimental
evidence showing that boron affects blood biochemical markers of energy
and mineral metabolism. Specifically, boron seems to be important for
energy utilization and the development and maintenance of bone.
Deficiencies: In vitamin D deficient animals fed very
low intakes of boron there were increases in total calcium loss,
interference with the use of blood sugar (glucose), fat, and insulin, and
dminished bone development. In humans, no deficiencies have been
documented in free-living populations. However, careful study of
volunteers in special living quarters shows that reducing the amount of
dietary boron causes changes in blood glucose and fat similar to that seen
in boron-deficient animals. For reasons not fully understood, boron
supplementation increases the percent of calcium intake lost in the urine
of both pre- and post-menopausal volunteers. Very low intakes of boron may
aggravate the symptoms of arthritis.
Diet recommendations: The usual adult dietary boron
intake in the US is about 1 mg/day. Use of boron supplements is not
recommended because neither an Estimated Safe and Adequate Dietary Intake
(ESADDI) or Recommended Daily Allowance (RDA) has been set for boron.
Food sources: The main sources of boron in the diet
are drinking water (which varies considerably between geographical
locations), milk and dairy products, and juices and beverages. On a wet
weight basis, fruits, vegetables, legumes and nuts (dicotyledonous plants)
contain much more boron than grains, breads, and cereals (monocotyledonous
plants). Animal products (meats, poultry, fish, etc.) contain very little
boron but milk and dairy products are major contributors to total boron
intake because of the large quantities consumed.
Toxicity: Almost all the boron that enters the body
from diet or absorption through damaged skin is promptly excreted in the
urine. However, this control process can be overwhelmed by very high boron
intakes that cause acute boron toxicity with nausea, vomiting, headache,
diarrhea, hypothermia, restlessness, skin loss, kidney damage, and death
from circulatory collapse and shock. The minimum lethal dose for humans is
not known although single doses of 18 to 20 g in adults have been fatal.
Chronic boron toxicity symptoms include poor appetite, nausea, weight
loss, and decreased sexual activity, seminal volume, and sperm count.
Death from boron poisoning is rare probably because of the emphasis placed
on maintaining electrolytic balance and supporting kidney function during
the worst part of the illness.
Recent research: In animal studies, boron improves the
production of antibodies that help fight infection and markedly decreases
peak secretion of insulin from the pancreas.
For further information:
Hunt, C.D. (1996) Biochemical effects of physiological amounts of
dietary boron. J. Trace Elem. Exp. Med. 9: 185-213.
Hegsted, M., Keenan, M. J., Siver, F. & Wozniak, P. (1991) Effect of B
on vitamin D deficient rats. Biol. Trace Elem. Res. 28: 243-256.
Prepared By:
Maren Hegsted, Ph.D.
Associate Professor
School of Human Ecology
Louisiana State University
Baton Rouge, LA 70803-0001
Phone: 504-388-1518
FAX: 504-388-2697
Email:
mhegste@unix1.sncc.lsu.edu
Curtiss D. Hunt, Ph.D.
Research Anatomist
USDA, ARS, Grand Forks HNRC
P.O. Box 9034
Grand Forks, ND 58202-9034
Phone: 701-795-8423
FAX: 701-795-8220
Email:
chunt@gfhnrc.ars.usda.gov
