ridecamp@endurance.net: Calcium Lactate (Long)

Calcium Lactate (Long)

RUN4BEAR@aol.com
Wed, 15 Oct 1997 08:55:10 -0400 (EDT)

In a message dated 97-10-15 01:34:22 EDT, you write:

Some concerns have been raised concerning the ingredient "calcium Lactate" in
Perform 'N Win Electrolytes. Here is the answer from the "horse's mouth".
Thanks Gayle!!!

Teddy

<< ___________________________________________________
Regarding: Calcium Lactate in Perform'N Win (PNW)

It has come to our attention that there has been concern expressed by an
individual(s) that the Perform'N Win electrolyte product contains calcium
lactate. We would like to address these concerns.

First, the amount of calcium in the solution when PNW is formulated
according to package directions is 1.9 mmol/L, equal to that found in
blood plasma.

Second, the calcium in PNW is complexed with various monovalent anions
of which lactate may be a small part -- we cannot detect lactate in our
assays of PNW solutions, which means that lactate is in
concentrations less than 0.2 mmol/L (only 1/5 that found in blood in
resting horses).

Third, some correct information regarding calcium and calcium salts:
Calcium must be supplied in the form of a calcium salt. Calcium
carbonate is a cheap source of calcium and therefore is widely used as a
calcium supplement, but is less well absorbed than salts formed with
monovalent anions such as citrate, malate, lactate, formate,
gluconate and chloride. All of these show a higher bioavailability in
humans and ruminants than calcium from
calcium carbonate. The above forms of calcium are available as
supplements. Calcium supplements in the form of calcium citrate/malate,
calcium citrate, calcium gluconate or calcium lactate are commonly
prescribed in oral doses of 500 to 1000 mg per day in humans, and higher
amounts have prescribed for specific situations. Calcium is absorbed more
efficiently when in a free ionic form (i.e., dissolved, as it is when you
mix PNW with water). Therefore the calcium in PNW is a readily absorbed,
highly available form of calcium.

Calcium is absorbed by the small intestine. The absorption of calcium
can be increased when there is a need for more calcium in the body.
Calcium is included in electrolyte supplements for exercising horses due
to the loss of calcium, along with sodium, potassium and chloride in the
sweat.

There is a common misconception that lactate is the "culprit" blamed for
fatigue in the horse and has frequently been blamed for horses tying up.
In anaerobic exercise, very high concentrations (greater than 10
mmol/L) lactate and its associated ion H+ inhibit
glycolysis and may contribute to muscle fatigue, as do the
diminishing stores of glycogen in the muscle. However, in race horses it
is not uncommon for very high levels of lactate to be detected in the
blood of the horse following intense exercise. If lactate were a problem,
then the horses that had the highest lactate levels would be the ones
having the most trouble. In fact, often the winner of the race was the
one with the highest lactate levels and the horse suffers no
apparent problems.

The reason for this is simple. Lactate is a breakdown product of
anaerobic glycolysis. When the muscle demands large amounts of energy in
a hurry, the glycogen in the muscle (or glucose in the blood) is broken
down without using oxygen to contribute to the increased energy demand.
As lactate accumulates in the muscles it is released into the blood,
and blood concentrations of lactate increase.

More important to the current issue, though, is that lactate is a
very good metabolic substrate in resting horses and humans and is in
fact preferred over glucose by skeletal muscle to provide energy to
the cells. Lactate is also more readily utilizable than glucose by muscle
cells (including heart muscle). All glucose that is taken up by cells must
first be broken down to lactate before the glucose carbons can be
utilized in cellular metabolism. Lactate is one of the most readily
absorbed and utilized energy sources by the body. For evidence, just
look at the horse or human or greyhound recovering from high
intensity exercise - lactates initially high at the end of the
exercise are rapidly lowered after a short period of recovery - much
faster than if a similar amount of glucose had been administered into the
blood.

Also, lactate generated in exercising muscle is a gluconeogenic precursor in
the
liver and in muscle recovering from exercise, i.e., converted by liver and
recovering muscle cells to make glucose (liver) or glycogen (muscle).
Liver glucose can then be released to the blood for more energy (for all
you biochemical junkies, this is called the Cori Cycle). The production
of glucose from glycogenolysis in the liver and from peripheral
precursors (i.e., lactate, glycerol, amino acids) can play an important
role when dietary glucose is not readily available. In the post-prandial
state (after a meal) much of the dietary glucose bypasses the liver and
is metabolized by the tissues such as the skeletal muscle. The lactate
recycles back to the liver where it is converted to glycogen for storage
in the liver. Lactate production by some tissues is a normal state for the
animal.

The lactate in PNW is barely detectable by a Nova Statprofile 9 ion
analyzer.
Of 25 electrolyte products analyzed, 9 have trace or measurable amounts of
lactate (<2 mmole/L). Two products tested had levels in the range of 4 to
7 mmole/L! Some of these products with much higher levels of lactate have
been in use for years. Several horses that have been a part of our total
sample group of over 300 horses have used these products with no noticeable
problems attributable to the lactate in the electrolyte product.

In the resting horse, lactate levels are generally 1-2 mmoles/L. In trials
where 8 L of PNW (ie, 8 oz at once) is administered to horses, there is no
detectable increase in blood lactates following ingestion (unpublished
data). This is because the lactate is absorbed through the small
intestine and can be used by the intestinal cells as a form of energy.
Any lactate passing into the bloodstream would also be quickly metabolized
as a source of fuel. During exercise, several researchers have suggested
that lactate may be an important oxidizable substrate during exercise. A
trained (i.e., well-conditioned physically) horse can use the lactate
efficiently as an energy source. In fact, there are reports of human
athletes
ingesting lactate as an ergogenic aid (performance enhancing substance).

Michael I. Lindinger, Ph.D., Dept. of Human Biology & Nutritional Sciences
University of Guelph, Guelph, ON Canada N1G 2W1
Phone: 1 519 824 4120 ext. 3752
FAX: 1 519 763 5902
email: mlindinger.ns@aps.uoguelph.ca

Gayle Ecker, B.Ed., M.Sc.,
Equine Research Centre, Inc.,
Guelph, ON Canada N1G 2W1
e-mail: gecker@uoguelph.ca



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