Monday, September 10, 2012

Stronger & Leaner or Fatter & Less Muscular W/ 4,000IU Vitamin D3 - What if Abstract and Data Tell Different Stories?

Image 1: The gap between the purported and the real world effects of vitamin D3 supplementation remains about as wide as the Grand Canyon - if not wider... and it takes a lot of ignorance towards your own study results to fill this divide up :-o
It is astonishing how fast things can change, only last Thursday I said on the SuppVersity Science Roundup on SHR, that hitherto trial after trial with supplemental vitamin D in the form of cholecalciferol (vitamin D3) failed to produce the desired results. And what do I have to tell you today? A group of researchers from the Purdue University and the College of Charleston have just published a study that appears to make it necessary for me, to at least rectify the previous assessment by stating: "With the exception of a recent trial from the Purdue University ..." Upon having a closer look at the actual data, it did yet turn out that the gap between what the abstract, on the one hand, and the real data, on the other hand, is about as wide as the still existent divide between the purported benefits from vitamin D supplementation and the real-world outcomes of respective trials.

It sounds as if Carillo et al. had finally done, what no one else has done before them, ...

Figure 1: Rel. odds ratio you make it to 100, 90-99, 80-89 yrs instead of dying before your 80th birthday - the results are based on a 44-year prospective study investigating the relation between midlife muscle strength and human longevity and found that "centenarians belonged 2.5 times  more often to the highest third of grip strength in midlife" (Rantanen. 2012)
... i.e. it sounds as if they had observed at least parts of the beneficial effects that are constantly being ascribed to vitamin D supplementation in 23 overweight and obese young men and women (age: 26.1 ± 4.7 y; BMI: 31.3 ± 3.2 kg/m²) with low, but not (officially) deficient 25-hydroxyvitamin D (25OHD) levels of 19.3 ± 7.2 (the official normal rage is between 9-80ng/ml):
"Vitamin D supplementation in overweight and obese adults during resistance training induced an early improvement in peak power, and elevated vitamin D status was associated with reduced waist-to-hip ratio." (Carillo. 2012)
So, according to the conclusion both strength and body composition improved n the course of the 12-week training intervention, which consisted of a 5min warm-up + light stretching (see also "Stretching Before Workouts Makes You Weak!"), followed by 8 machine-based (Kaiser Equipment) resistance exercises, namely
  • leg extensions, leg flexions, leg presses, 
  • hip adductions & hip abductions, 
  • chest presses, seated rows & lat pull downs,
at a progressively increasing intensity, starting with 70%RM in the first weeks and 80% of the 1RM for three sets of 8 repetitions (or "momentary muscular failure"), right? Sounds like that, I should say!

Serious training + serious nutrition = serious gains... but what about vitamin D?

Moreover, with the additional protein shake (360 kcal; 8 g fat, 54 g carbohydrate, 20 g milk protein isolate, 100IU vitamin D and 300mg of calcium) every participant had to consume during the hour following the exercise sessions, the scientists rightfully call their experimental protocol "anabolic". It is thus no wonder that aside from ostensible weight loss and strength gain, both of which you would expect in formerly sedentary subjects, the subjects in both groups did also increase their lean mass (see figure 2, right) .
Figure 2: The hushed up truth Part I => "Gain less muscle and more fat with vitamin D" (right) and have a statistical significant, but real world highly questionable correlation between 25OHD and waist-to-hip ratio of R²=0.205, yet not vitamin D3 supplementation (small, insert; all data based on Carillo. 2012)
What the scientist didn't tell you in the afore-cited conclusion to their abstract, though, is that the group which received an additional 4000 IU vitamin D3 instead of the microcrystalline placebo, did gain less lean mass and more fat mass than their peers. And while the inter-group difference for each of these parameters is statistically not significant, I would bet that their ratio, i.e. the ratio of lean mass to fat mass gains, in this case 5.6 kg muscle per 1kg fat in the placebo vs. 1.8kg muscle per 1kg fat in the vitamin D3 group, were! A difference, by the way, which is not simply a result from the greater increase in energy intake in the vitamin D3 group (see figure 2, left), as the latter should have increased both, lean and fat mass gains. What it effectively did, however was exactly the same as a vitamin D supplement in a rodent study it worked as a "fat-synthesizer" (see "Vitamin D3 a "Fat Synthesizer"!? Rodent Study Shows +33% Increased Fat Deposition in Vitamin D3 Supplemented Mice.")

"Something is rotten is rotten, here, and I can tell you Horatio heaven did not direct it"* 
* I hope you like Shakespeare ;-)
Figure 3: If you want lower PTH vitamin D may be worth it, if not, you get only a non-significant worsening of your glucose metabolism; in addition to increases in body fat and lower lean mass gains (cf. figure 2) obviously (Carillo. 2012)!
The fact that we see only increased fat but not muscle gains, however, only adds to a whole list of observations which show that irrespective of how cleverly the abstract tries to make this look like the "break-through study" about the benefits of vitamin D supplementation, we are yet dealing with nothing more but another confirmation of the futility of vitamin D3 supplements. After all, the 4,000 IU of D3 were not even able to increase the levels of 25OHD to a statistically significant (inter-group differences!) degree (see figure 2). If you also take into consideration that
  • contrary to the actual vitamin D levels shown in figure 2 (small insert), the provision of 4,000IU/day of D3 did not (!) correlate with a reduction in waist-to-hip ratio,
  • the vitamin D3 supplement did not increase serum calcium (see figure 3, top), and
  • the participants who received the active supplement, exhibit an allegedly non significant, but still existent worsening of their glucose metabolism (cf figure 3, bottom) 
it must be allowed to ask whether the -34% reduction in PTH, which is the only blood parameter that exhibited a statistically significant inter-group difference, is reason enough to take an otherwise at best ineffective supplement.

"But it does make you stronger!" - Nope, that's another trick!

The latter is all the more true, because the participants in the vitamin D arm of the study may have increased their peak power faster (see figure 3), but the did not increase their overall strength on any of the exercises to a greater extend than the men and women in the placebo arm of the study.
Figure 4: Relative (left) and absolute strength gains (middle) as well as time course of peak power changes
(calculations based on Carillo. 2012)
The notion that this was the case, is simply a consequence of selective reporting (or in this case "highlighting") of study outcomes (cf. Chan. 2004); or, in other words, we are (mis-)lead by the overemphasis Carrillo et al. put on the early (first 4-weeks) increase in peak power, and their corresponding nonchalant surreptitious reference to the fact that "[n]o other improvements were observed with supplementation" (Carillo. 2012). In short, there is a ballyhooed increase in "peak strength" in the early weeks, but this does not change the fact that the participants in the vitamin D3 arm of the study ended up gained more fat and less muscle, and were - at the end of the trial - neither stronger nor leaner (neither in terms of their body fat %, nor in terms of their waist-to-hip ratio, which was not associated with supplementation!)

From a mere statistical perspective, you could even argue that nothing happened. And let's be honest does that vindicate vitamin D supplementation? I don't think so! If you want to make a change, get big and buffed or strong and sexy, get your lazy ass off the couch and out in the sun, work out regularly, prepare your own nutritious food and drop all useless supplements (see "Three Simple Rules of Smart Supplementation") ... but you know all that, already, right?
Image 2: Does "doing science" come down to presenting only those facts that are in line with the orig. research hypothesis, these days? (img.
Some more general remarks: Now, I could hardly care less that this is yet another study showing that vitamin D3 is a supplemental non-starter., but there is one thing that really drives me up the walls and this is the fact that you as an intelligent and critical SuppVersity reader who is determined and willing to question what he reads on the Internet, but in 99% of the cases won't have access to full-texts of papers like this, are being mislead by abstracts, which are written for the sole purpose to tailor to the original research hypothesis
"[...] that vitamin D supplementation during resistance training would result in greater gains in muscle mass and function as well as improved glucose tolerance compared to exercise training alone." (Carillo. 2012)
and that irrespective of the fact that the actual data disproves this hypothesis!

  • Carillo AE, Flynn MG, Pinkston, C, Markofki MM, Jian Y, Donkin SS, Teegarden D. Impact of vitamin D supplementation during a resistance training intervention on body composition, muscle function, and glucose tolerance in overweight and obese adults. Clinical nutrition (Edinburgh, Scotland) 3 September 2012.
  • Chan AW, Hróbjartsson A, Haahr MT, Gøtzsche PC, Altman DG. Empirical evidence for selective reporting of outcomes in randomized trials: comparison of protocols to published articles. JAMA. 2004 May 26;291(20):2457-65
  • Rantanen T, Masaki K, He Q, Ross GW, Willcox BJ, White L. Midlife muscle strength and human longevity up to age 100 years: a 44-year prospective study among a decedent cohort. Age (Dordr). 2012 Jun;34(3):563-70. Epub 2011 May 4.