Monday, June 1, 2015

Older Human Study Shows: 2.72g Carnitine per Day Ward Off Fat Gains - Specifically on the Trunk | User Question: Are We Missing Out If We Are Not Using Carnitine?

SuppVersity reader Derek D. wants to know if 2013 study shows we are missing out if we don't use carnitine.
When I answered your questions on Facebook, the other day, Derek D.'s question about the results of a 2013 study by Stephens et al. stood out, because Keller's study suggest that carnitine may be significantly more useful while bulking than it is during a cut (which is still what it is marketed for).

If you are a long-term SuppVersity reader, you will be aware that this is not the first SuppVersity article discussing a study that points to the use of carnitine outside of dieting scenarios. In 2013, for example, I wrote about a study by Keller et al. (2013). A study that found significant increases in pro-anabolic hormones and proteins, and a 7% improvement in lean-to-total-mass ratio in rodents in response to a relatively low amount of carnitine in the diet.
You can learn more about carnitine at the SuppVersity!

Carnitine for Acute Endurance Perf. Boosts

Carnitine too Low in Many Vegetarians

Carnitine? Which Type Should You Use?

Carnitine as a Body Recomp Agent?

Choline, Carnitine, Caffeine = Fat Loss Booster

Will Carnitine Increase Your Cancer Risk?
Now, what's interesting about the study Derek asked about is that it was done in human. In only 12 healthy (the scientists planned for 16 which is not much better, but there were 4 drop-outs), non-vegetarian, male recreational athletes ("non-vegetarian" is important because vegetarians and vegans may benefit much more from carnitine supplements | learn more), to be specific. It's also noteworthy that Stephens et al. used dual-energy X-ray absorptiometry (DEXA) to assess the body composition of the subjects and incorporated a complex array of gene essays to assess what could drive the changes the UK researchers observed in response to the ingestion of a beverage containing 1.36 g of L-carnitine and 80 g of carbohydrate twice a day.
Figure 1: The changes look to good to be true and may in fact be purely random (Stephens. 2013).
In that, the high GI (Vitargo(R)) carbohydrate source was added mostly to stimulate insulin-mediated muscle carnitine transport (adding CHO + choline would have been even more effective | learn more) and not to fatten the who consumed their two orange-flavoured beverages in the morning and 4h later (without foods!) for 12 weeks up.

It may thus have been a bit surprising for the researchers, when they realized that the subjects in the control group gained a significant amount of (trunk) fat over the 12-week study period - a pro-obesogenic effect that was prevented by the additional 2.72 g/day of carnitine which also increased the total energy expenditure (significantly) and the fatty acid oxidation (non-signifcantly) over Control.
The more choline the better the carnitine retention; and the better the retention the less high carnitine red mead you'll have to eat... just kiddin'. Irrespective of whether you do or don't eat red meat. Choline supplements are a much better way to increase carnitine retention than tons of carbs | learn more.
So, carnitine keeps you lean on a bulk? In view of the fact that there was neither a dietary nor an exercise control in place, the results of a small scale study like this has no value whatsoever. I don't care about the observed increases in muscle total carnitine, long-chain acyl-CoA and whole-body energy expenditure. I don't care about the seventy-three of 187 genes relating to fuel metabolism that were upregulated in Carnitine vs. Control after 12 weeks. And I don't care about the fact that some of these genes were involved in 'insulin signalling’, ‘peroxisome proliferator-activated receptor signalling’ (PPARs are involved in fatty acid metabolism), either.

What I do care about is that a study without rigid dietary and exercise control with only 6 subjects in each of the two groups can produce outstanding results that are nothing but random and that's why the study at hand doesn't provide the evidence that would be necessary to answer the question in the headline, i.e. "Are we missing out if we don't use carnitine?", affirmatively | Comment on Facebook!
References:
  • Keller J, Couturie A, Haferkamp M, Most E, Eder K. Supplementation of carnitine leads to an activation of the IGF-1/PI3K/Akt signalling pathway and down regulates the E3 ligase MuRF1 in skeletal muscle of rats. Nutrition & Metabolism. 2013; 10:28. 
  • Stephens, Francis B., et al. "Skeletal muscle carnitine loading increases energy expenditure, modulates fuel metabolism gene networks and prevents body fat accumulation in humans." The Journal of physiology 591.18 (2013): 4655-4666.