Supplement Performance - Creatine Plus Phosphate

Creatine Supplementation

Creatine is a naturally occurring amino acid that is obtained from the diet

and/or synthesized endogenously (within the body) from the amino acids glycine,

arginine and methionine. Creatine has become a popular nutritional supplement

among athletes. The most commonly used protocol is to ingest a daily total of 20 to

30 grams of creatine, usually creatine monohydrate, in four equal doses of five to

seven grams dissolved in fluids over the course of day. (For a detailed review on

creatine supplementation strategies, see my article Creatine Loading Strategies in

November issue of MD).

Although not all studies report significant results, the preponderance of

scientific evidence indicates that creatine supplementation appears to be a generally

effective nutritional ergogenic aid for a variety of exercise tasks in a number of

athletic and clinical populations.1

For example, short-term creatine supplementation has been reported to

improve maximal power/strength (5-15%), work performed during sets of maximal

effort muscle contractions (5-15%), single-effort sprint performance (1-5%) and work

performed during repetitive sprint performance (5-15%).1 Moreover, creatine

supplementation during training has been reported to promote significantly greater

gains in strength, fat-free mass and performance, primarily of high- intensity

performance tasks.1

In the 1970s, Soviet scientists showed that creatine supplementation

improved athletic performance in short, intense activities such as sprints.2 According

to Dr. Michael Kalinski, a former Chairman of the Exercise Biochemistry Department

in the Kiev State Institute of Physical Education (Kiev, Ukraine, USSR), the Central

Institute of Physical Culture (CIPC) in Moscow initiated a long-term research

program to characterize the role of creatine in muscular performance and its use to

enhance muscle function. Also, Soviet scientists redirected their research from

academic studies on creatine metabolism in animals to applied studies on the

effects of creatine supplementation on human physical performance.2

For example, members of the USSR national track and field team who took

creatine supplements improved their performance in the 100-meter dash by one

percent and in the 200-meter sprint by 1.7 percent.2 As a result of these studies,

the CIPC officially recommended use of creatine supplements to enhance physical

capacity and the efficacy of exercise training. In additon, USSR national athletes

were routinely given these supplements.2

Some clinicians have expressed concern about the effects of creatine on

renal function. Drs. Pritchard and Kaira reported a case study of renal dysfunction

associated with creatine,3 but their conclusion that creatine was responsible for the

renal dysfunction is clouded by previous history of renal nephritic syndroma that was

stabilized by cyclosporine. It was unclear whether the observed improvement in

renal function following creatine withdrawal was due to adverse effects of creatine

itself, impurities in the creatine products, creatine/drug interactions and/or other

factors.

In three small studies, no adverse effects of creatine on renal function were

reported following either short-term4,5 or long-term supplementation of two to 30

grams per day for up to five years.6 Moreover, Dr. Richard Kreider and co-workers

recently reported that long-term creatine supplementation (up to 21 months) does

not appear to adversely affect markers of health status (metabolic markers, muscle

and liver enzymes, electrolytes, lipid profiles, etc.) in athletes undergoing intense

training in comparison to athletes who do not take creatine.7 There have also been

anecdotal reports of muscle cramping and strains associated with creatine

supplementation. However, Dr. Greenwood and colleagues recently reported that

creatine supplementation does not appear to increase the incidence of injury or

cramping in Division IA college football players.8

Phosphate Supplementation

Among the inorganic elements, phosphorous is second only to calcium in

abundance in the human body. Approximately 85 percent of the body´s

phosphorous is in the skeleton, one percent is found in the blood and body fluids,

and the remaining 14 percent is associated with soft tissue such as muscle.9

Phosphorous is of vital importance in intermediary metabolism of the energy

nutrients, contributing to the metabolic potential in the form of high-energy

phosphate bonds, such as ATP, and through phosphorylation of substrates.

Phosphate also functions in acid-base balance. Within cells, phosphate is the main

intracellular buffer.

Further, phosphate is involved in oxygen delivery. In red blood cells,

synthesis of 2,3-diphosphoglycerate requires phosphorus. Decreased 2,3-

diphosphoglycerate diminishes release of oxygen to tissues. Phosphorous is widely

distributed in foods. The best food sources are meat, poultry, fish, eggs and milk

products. Nuts, legumes, cereals, grains and chocolate also contain phosphorous;

however, animal products are superior sources of available phosphorus compared

with cereals and soy-based foods. Many phosphate-containing supplements are

available commercially, including K-Phos® and Neutra-Phos K®, which also provide

potassium. For maximum bioavailability, these supplements should not be ingested

with zinc, iron, or magnesium.9 Calcium (as calcium acetate or calcium carbonate)

also inhibits phosphorous absorbtion.9

Phosphate supplementation (“phosphate loading”) has been proposed as an

aid to athletic performance (Table 1).10 Studies investigating the ergogenic value of

phosphate supplementation date back to the 1920s. Early studies suggested that

phosphate salt supplementation could be used to increase physical working

capacity.10

Much of the contemporary interest in phosphate supplementation as a

potential ergogenic aid emanated from a report by Dr. Cade and colleagues in the

early 1980s.11 Results revealed that phosphate supplementation significantly

increased resting serum phosphate and red cell 2,3-diphosphoglyserate levels. In

addition, phosphate supplementation decreased submaximal lactate while

increasing maximal oxygen uptake. The greatest increase in maximal oxygen

uptake occurred in subjects ingesting sodium phosphate for two consecutive testing

trials.

Dr. Richard Kreider and co-workers conducted the most extensive study to

date to evaluate the ergogenic value of phosphate supplementation.12 In this study,

six highly trained male cyclists participated in a placebo-controlled, double blind

crossover study to determine the effects of sodium phosphate supplementation on

metabolic and myocardial adaptations to maximal exercise and 40-km time trial

performance. Subjects ingested either four grams per day of tribasic sodium

phosphate or a glucose placebo for five days. On the fourth day, subjects performed

either an incremental maximal cycling test or a 40-km stimulated time trial under

controlled laboratory conditions using the subjects’ racing bicycle attached to a

computerized race stimulator.

Analysis of maximal test results revealed that phosphate supplementation

significantly increased pre-max serum phosphate levels (17%), maximal oxygen

uptake (9%), minute ventilation (8%), ventilatory anaerobic threshold (10%),

echocardiographically-determined mean ejection fraction (4%) and myocardial

fractional shortening (8%). During the 40-km time trial, phosphate loading

significantly increased mean power output (17%), oxygen uptake (18%), ventilation

(15%), heart rate (8%), ejection fraction (13%) and fractional shortening resulting in

an eight percent reduction in performance time. These findings provide evidence

that sodium phosphate supplementation provides ergogenic value to highly trained

athletes.

According to recent review with Dr. Kreider, “Most studies investigating the

effects of sodium phosphate supplementation (three or four grams per day for three

or four days) on maximal aerobic capacity and/or endurance exercise performance

have reported ergogenic benefit… On the other hand, it appears that acute and/or

chronic calcium phosphate supplementation provides little ergogenic value.”10

Table 1. Proposed Theoretical Ergogenic Value of Phosphate

Supplementation

• Elevates extracellular and intracellular phosphate concentration

• Stimulates glycolysis and energy metabolism

• Increase the availability of phosphate for oxidative phosphorylation

and creatine phosphate synthesis

• Increases 2,3-diphosphoglycerate synthesis and peripheral extraction

of oxygen.

• Enhances myocardial and cardiovascular responses to exercise

• Serves as a metabolic buffer

• Increases anaerobic threshold and maximal oxygen uptake

• Improves exercise performance and/or efficiency

• May enhance psychological responses to exercise

Data from Kreider, 1999

Creatine Phosphate Supplementation

In their recent book Supplements for Strength-Power Athletes13, Drs. Jose

Antonio and Jeffrey Stout quoted results by Dr. Wallace and colleagues published in

Coaching and Sports Science Journal and unpublished results by Dr. Eckerson. Dr.

Wallace and co-workers investigated the effect of supplemental creatine alone

versus creatine plus phosphate on muscle power. Male and female subjects were

given either five grams of creatine four times per day or five grams of creatine plus

one gram of phosphate four times per day for five days. The combination of creatine

plus phosphate resulted in a significantly higher muscle power output, suggesting

performance benefits more from a combination of phosphates and creatine than

from creatine alone.

Dr. Eckerson and colleagues examined the effects of creatine alone versus

creatine plus phosphate on anaerobic working capacity. Male subjects were

randomly put into one of three treatments: placebo, five grams of creatine, or five

grams of creatine plus one gram of phosphates. Each subject was asked to dissolve

the supplement in 16 ounces of water and ingest it four times per day for six

consecutive days. The subjects performed a cycle ergometry test to determine

anaerobic working capacity. The placebo and creatine groups increased anaerobic

working capacity by –3.0 percent and 16.0 percent, respectively. The creatine plus

phosphate group increased anaerobic working capacity by 49 percent.

Phosphate and Resting Metabolic Rate

Phosphate supplementation has also been suggested to affect energy

expenditure. For example, Dr. Kaciuba-Uscilko and colleagues reported that

phosphate supplementation during a four-week weight loss program increased

resting metabolic rate.14 Further, Dr. Nazar and co-workers reported that phosphate

supplementation during an eight-week weight loss program increased resting

metabolic rate by 12-19 percent and prevented a normal decline in thyroid

hormones.15 Consequently, it’s possible that phosphate could serve as a potential

thermogenic nutrient in diet supplements.

Summing Up

The preponderance of scientific evidence indicates that creatine

supplementation appears to be a generally effective nutritional ergogenic aid for a

variety of exercise tasks in a number of athletic and clinical populations. There is

some evidence suggesting that sodium phosphate supplementation may enhance

aerobic capacity. Recent data suggest that combined creatine and phosphate

ingestion improves anaerobic working capacity more than creatine ingestion alone.

According to Drs. Jose Antonio and Jeffrey Stout, take a one-gram serving

phosphates (preferably a sodium-potassium mix) with every serving of creatine

during the loading phase, which would be four times daily for six days.