Study: Caffeine Supplements for Extra Fitness

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If you want to benefit from the effects of caffeine on endurance, it’s best to take caffeine in its pure form instead of drinking coffee or other caffeine-containing beverages. The other substances in coffee may have a counterproductive effect that reduces the effectiveness of caffeine. Furthermore, energy drinks are relatively expensive compared to caffeine tablets or capsules, considering the amount of caffeine they contain.

Caffeine is not Coffee

Over the past few months, I have written several articles about caffeine, both for Buildmybody and Fitsociety. In these articles, I often translate (just like the research I refer to) quantities of caffeine into the number of cups of coffee. This is to give you an idea of how much coffee you should or should not drink to achieve certain results. However, this may not be accurate. Apart from the difficulty of calculating the exact amount of caffeine per cup of coffee (how big is the cup, what kind of coffee, etc.), it seems that caffeine ingested with coffee does not have the same effects as caffeine ingested alone [1]. This suggests that one or more components of coffee may affect the action of caffeine.

One cannot extrapolate the effects of Caffeine to Coffee; there must be a component(s) of Coffee that moderates the actions of Caffeine. T.E. Graham, University of Guelph, Canada

Coffee: More than Caffeine

I recently wrote that the added value of caffeine on endurance is greater (and better demonstrated) than that of caffeine on (maximum) strength. Especially when it comes to efforts between 30 and 120 minutes, caffeine ensures that you can endure longer or perform more within a certain time frame [2-5]. This is mainly because caffeine increases the amount of epinephrine, which leads to higher fat burning. This results in more free fatty acids becoming available in the blood as an energy source [1]. As mentioned, these results are often translated into caffeine-containing beverages and foods such as coffee, tea, and cola. Especially coffee contains caffeine in higher concentrations compared to other types of food and beverages except for some popular energy drinks [6,7]. In the preparation of coffee (including roasting the beans, grinding, and adding hot water), hundreds of substances are dissolved besides caffeine [8,9]. Many of these are present in higher concentrations than caffeine. Think of fats, carbohydrates, and proteins, which make up more than 60% of the content compared to the 2% of caffeine [9]. These other substances can have their own influence on metabolism and energy supply, independent of the influence of caffeine [6,8,10]. In addition, there are also substances present in small amounts in coffee that can have metabolic effects despite their low concentration, such as niacin. The effects of coffee cannot always be attributed to caffeine alone.

Effect of Caffeine in Coffee vs. Pure Caffeine

It’s clear that the other substances in coffee have their own effect. Canadian researchers from the University of Guelph were particularly interested in a possible influence of these substances on the action of caffeine [1].

Caffeine-Free Coffee with Added Caffeine Has Less Effect on Endurance than the Same Amount of Caffeine Taken Alone

They refer to research in which the effect of decaffeinated coffee with added caffeine on endurance was examined [11]. In this case, decaffeinated coffee with added caffeine was chosen to ensure the amount of caffeine. This caused the participants in the study to be able to cycle an average of 21% longer (at 80% VO2max) one hour after ingesting the coffee. However, researchers from the University of Guelph [2,4] and Johns Hopkins Hospital [12] have seen results in various studies with pure caffeine where endurance was improved by 28 to 43 percent. According to them, these differences cannot be explained by the difference in dosage. Therefore, they consider the possibility of a inhibitory effect of the other ingredients on the effect of coffee. Previous research has already examined the effect of the same amount of caffeine taken alone and in coffee and found no difference, but that was in resting subjects [13]. The Canadians wanted to investigate this difference now in endurance. Nine experienced young runners were selected for the study. Unfortunately, two of them were classified as “moderate” users. “Moderate” in this case means they consume less than <500mg of caffeine per day. However, in the article about caffeine as a fat burner, I already referred to research showing that with a higher daily intake than 300mg per day, saturation can occur, preventing increased fat burning. These two could therefore influence the results without this being taken into account. The participants had to run five times to exhaustion at an intensity of 85% VO2max. Prior to these tests, they received one of the following beverages:

1. A placebo consisting of dextrose with water
2. Caffeine capsules with water
3. Coffee
4. Decaffeinated coffee
5. Decaffeinated coffee with added caffeine

In all cases where caffeine was given, it contained approximately 4.45mg of caffeine per kilogram of body weight of the participant. The researchers hypothesized that all forms of caffeine would lead to improved performance, but that the capsules (without the other components of coffee) would yield the best results. The graph on the right shows that their hypothesis turned out to be correct. It shows how long the participants could cycle under the different conditions. We see that the placebo led to the worst performance. Pure caffeine had the best result. With this, they could run 2-3 kilometers further, 9.9 minutes longer than with the placebo. The researchers mainly attribute this to the influence of caffeine on epinephrine. Although the same amount of caffeine “bioavailable” entered the blood after ingestion of capsules or coffee with caffeine, the influence on epinephrine was different. In the case of regular coffee and decaffeinated coffee with added caffeine, this led to only 50% of the increase in epinephrine that the capsules had as an effect.

In summary, we investigated the effects of caffeine ingestion in association with coffee on endurance and metabolism during exercise. The results clearly demonstrated that caffeine ingested in this form does not alter the bioavailability of caffeine but fails to enhance endurance. In addition, the increase in plasma epinephrine that is normally observed in the first hour after ingestion was moderated. The results suggest that other compounds in coffee act to antagonize the responses observed when caffeine is ingested independent of coffee. T.E. Graham, University of Guelph, Canada

Compounds in Coffee with Counterproductive Effects of Caffeine

In this case, coffee was compared. So we don’t know what influence, for example, the other components in tea, cola, or energy drinks would have. Therefore, we want to know which substances in coffee cause this inhibitory effect on caffeine. The researchers suspect that the probable cause lies in the so-called cholinomimetics and opiate receptor antagonists found in coffee (don’t worry, you won’t be asked about that during the test) [14]. Researchers from Georgetown University injected these cholinomimetics into rats, after which their heart rate and blood pressure decreased. An opposite action of caffeine.

Compounds in Tea with Counterproductive Effects of Caffeine

In tea, we see a similar situation where the theanine in tea has a counterproductive effect compared to the caffeine in tea. For example, blood pressure and alertness are less increased than when only caffeine was ingested [15].

Energy Drinks with Caffeine: Amount of Caffeine Can Be Disappointing

As mentioned, there are energy drinks with caffeine. In most cases, these do not contain theanine, although there will undoubtedly be energy drinks to which tea has been added. Most likely green tea because it is popular and sells well. However, energy drinks contain many other substances that you may question if you want them if you are looking for caffeine, such as sugars, for example. Then you still have the point that apparently you cannot rely on the amount of caffeine stated on the can. Researchers from Florida compared the amount of various energy drinks and soft drinks [17]. It was noticed that in a can of Red Bull “only” 66.7mg of caffeine was present instead of the promised 80mg (see figure on the right). In another case, that of “Hair of the Dog,” the label indicated that there was caffeine in it, while the researchers did not find any.

Caffeine in Coffee: Same Cups of Coffee from Starbucks with Large Differences in Caffeine

Those same researchers once compared the caffeine content of different coffee shops (in the American sense of “coffee shop”). They also went to the same store for the same cup of coffee several days in a row, but there were still large differences in caffeine content. This ranged from 259mg per (large) cup to 564mg! You can’t calculate in advance how much coffee you need to drink for a certain amount of caffeine.

Prefer Caffeine Capsules over Coffee to Improve Endurance

Why drink coffee or energy drinks when it comes to caffeine? Caffeine capsules are readily available and comparatively much cheaper. A 25cl can of Red Bull costs around €2.20, supposedly giving you 80mg of caffeine, but possibly even less. For €4.50, you can get 100 tablets of 200mg of caffeine from Tested Nutrition at bodyenfitshop, for example. That’s almost 250 times more caffeine for a price that’s only double! I’ll show the deals below so you can do the calculation yourself if you want.

References

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