Answer Dr. Andro: As you may have noticed, I took the freedom to set Learner's question into a broader context. A context I broached in my dissertations on Athletic Edge Nutrition's new creatine product Creatine RT on Tuesday, Aug 16, 2011. Thus, the questions I will be trying to answer (unfortunately, I have to rely on existing studies and do not have my own lab, here ;-) are the following ones:
- How does creatine get into the blood?
- How does creatine get into the muscle? (cf. Part II)
- What can influence these processes?
How does Creatine Get into Your Blood?
In essence all these esters, acids, chlorides and other "creatine + X"-combinations have been designed to mug you... ah, I mean to increase the amount of creatine that makes it into your bloodstream, or in other words, to increase bioavailability. Now, as Wesley Mc Call and Adam Persky state in chapter 13 of Creatine and Creatine Kinase in Health and Disease, there are four potential reasons why creatine bioavailability could be less than 100%, in the first place:
- Degradation (to creatinine) in the stomach
- Insufficient dissolution, i.e. passing the intestines "unsolved"
- Problems with creatine uptake by the epithelial cells
- Degradation by gut bacteria
We know for certain that creatine degradation is maximal at pH 3 (Cannon. 1927, cf. figure 1). Now, a healthy stomach should have a pH of 1 and for about 84 years everybody (supplement producers included) would have been able to take a look at the data of the 1927 study by Cannon and Shore, who found that after 25 h in a solution with a pH of 1 only ~2% of the creatine would have "degraded" into its dehydration product creatinine and that the often cited "breakdown" of creatine monohydrate in the acidic milieu of your stomach is not really an issue, after all.
|Figure 1: Percent creatinine in solution of previously pure creatine after 25, 50, 125 and 1903h at a certain pH (data adapted from Cannon. 1927).|
|Image 2: You probably expected that it ain't advisable to take your creatine with a Big Mac, but would you have guessed that juices are counter-indicated, as well?|
Tip: You better wait at least 90 minutes after your last meal, before you flush down your creatine with water, as even the presence of carbohydrates from juices has been shown to "delay the time to peak concentration", which usually is less than 2h and to decrease the maximal concentration at peak concentration (Mc Call. 2008).
2. Creatine (Monohydrate) could not dissolve and thus be not absorbed
|Illustration 2: Creatine is taken up by enterocytes in the jejunum and the illeum.|
Interestingly, a study by Harris et al. suggests that the creatine from meat such as the paddies of the burger in image 2 (I am assuming here that there is still some meat in McDonalds burgers / here in Germany they have recently begun advertising their meat quality ;-) is more readily absorbed (this refers to absolute amounts, not to the time-course) than either creatine suspended (=more creatine in water than can be solved) in water or creatine tablets / lozenges (Harris. 2002). A probable explanation for this phenomenon could be that the creatine is safely contained in the meat, until the latter is broken down by enzymes that are activated as the pH of the stomach is decreasing. Thus only very limited amounts of free creatine will be exposed to pH levels in the detrimental3-4 range.
3. Creatine could simply not be taken up by the enterocytes in the small intestine
Obviously, any general digestive problem related to nutrient transport across the epithelial barrier in the intestines could compromise creatine uptake, as well. As mentioned earlier the presence of large (180g) amounts of carbohydrates have been shown to slow gastric emptying and consequently creatine absorption, considerably (Vist. 1995). In addition several other meal-constituents could also increase the pH temporarily and thus initially decrease solubility (when pH is still very high) and consequently increase creatine to creatinine breakdown (when the pH passes the critical 3-4 range, see above).
4. Creatine could be degraded by bacteria in the gut
|Image 2: Biridobacterium tongum is a probiotic and a natural enemy of putrefective bacteria, who "suffocate" from the lactic acid, acetic acid and bacteriocins (image from dophilus.com)|
Conclusion: Absorption should not be an issue
If your gut is healthy, acidic and free of pathogenic amounts of putrefective bacteria there is absolutely no reason you could have problems absorbing creatine - especially if you stick to my recommendations and
- do not escalate single dosages beyond 5g,
- take your creatine on an empty stomach (or at least 90 min after your last meal)*
(taking creatine with carbs + protein will increase breakdown to creatinine, and decrease the maximal serum levels, but, on the other hand, it will increase muscular creatine retention, cf. Part II)
- do not take creatine with a meal or protein or large amounts of carbohydrates**
(read more on the carb issue in the 2nd part of this installment of "Ask Dr. Andro", tomorrow)
- increase your stomach pH beyond 6, or
- decrease your stomach pH below 2
|Figure 2: Relative increase in creatine in dry muscle mass of horses, after supplementation with creatine monohydrate, kre-alkalyn or Gastner's patented creatine + sodium carbonate +sodium hydrogen carbonate formula (Gastner. 2010)|
|Image 3: Kre-Alkalyn - expensive, but probably |
useless - at least when taken with food.