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.
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.