As a physically active individual in today's world, you are likely to be bombarded with all sorts of claims about nutritional supplements that will enhance your athletic performance. In reality, very few have been scientifically proven to have any effect on athletic performance.

Here are two known to work and special concerns about their use by diabetic athletes:

Caffeine

Caffeine is a central nervous system stimulant found naturally in many foods and drinks such as coffee, tea, cocoa and chocolate. Caffeine directly stimulates the nervous system and increases arousal. At the same time, it increases levels of circulating free fatty acids (blood fats) and provides an alternate fuel source for your exercising muscles.

Improves Training Performance

Caffeine also stimulates the release of calcium in contracting muscle, allowing for greater force production and muscular strength. Research studies have found increases in performance in events primarily using the immediate, short-term, and aerobic energy systems. Doses of caffeine in legal limits may actually improve running times in various length events from one mile up to marathons.

A legal amount, according to the International Olympic Committee, is an intake of less than 800 mg, depending on your body size and weight. For comparison, a five oz. cup of coffee contains 100 to150 mg, a cup of tea 50 mg, a can of cola 40 mg, a cup of cocoa five mg, a No Doz tablet 100 mg and a Vivarin tablet 200 mg. Abstaining from caffeine intake for two to three days prior to using it for sports usually increases its effectiveness, as you will be less habituated to its effects. The down side of its use is its diuretic effect, which causes you to lose more water through your urine. High blood sugar can increase your water losses as well.

You will need to be especially cautious about maintaining proper hydration with intake of caffeine, doubly so if participating in exercise in a hot environment or when blood sugar levels are already elevated above normal.

Creatine

Creatine is a natural amine present in animal meats that can be synthesized by your liver and kidneys from other amino acids in your body. Creatine is the main component of the phosphagen energy system that provides immediate energy for activities lasting less than 10 seconds.

Your normal daily dietary intake of creatine is one gram, with an additional gram being synthesized by your body each day. Oral supplementation with creatine monophosphate by athletes has been found to increase the free creatine and creatine phosphate (CP) stores in muscle as well as body weight, mainly due to water retention in muscle.

Also Improves Training Performance

Many studies have found that creatine supplementation of 20 to 30 grams per day for five to seven days may exert an effect on performance in explosive sports, primarily those that involve high-intensity, short-term and repetitive exercise bouts with brief recovery periods. As a result, athletes may be able to train at a higher level, leading to an increase in muscle mass and gains in strength and power. The initial creatine-loading phase usually lasts for less than a week and is typically followed by a maintenance dose of two to five grams per day.

Creatine supplementation has not been shown to enhance endurance performance and may, in fact, be detrimental to distance running performance due to the resulting increases in body weight.

Side Effects

As of yet, there are no known long-term detrimental effects from creatine supplementation for normal individuals. However, excess creatine is excreted by the kidneys as creatinine. In addition, in non-diabetic individuals, creatinine clearance levels have been shown to increase slightly during periods of creatine loading. The additional urinary creatinine excretion also pulls more fluid out of your body and can cause dehydration. Severe muscle cramping during exercise has been reported by many power athletes, even when they have been taking in extra water to offset creatine's potential dehydrating effect.

Creatine Studies in People with Diabetes

No studies have examined the effects of creatine loading on individuals with diabetes. However, you should be cautious in your use of this substance due to the additional stress placed on your kidneys caused by its excretion and the risk of dehydration. Given the added health risks, if you choose to supplement, your intake should not exceed 20 grams per day for a period of five days (loading phase) with a subsequent intake of no more than three grams per day (maintenance phase).

If you have an elevated creatinine clearance, microabuminuria or overt proteinuria, supplementing with creatine is not advised.