Science Round Up Seconds: 2x10-15Min Of Tanning Per Week Equal 2,000IU Vitamin D3/Day. Low GI Diet Adds 9.4 Years to Your Life. Estrogen + Progestin = Bad Choice For ERT. 3g Salt/Day = 33% Lower Magnesium Retention

It has not always been this way, but these days our beauty ideal has at least one potentially healthy feat: The tan!

I don't know if you have been able to listen live to yesterday's in many ways "extraordinary" episode of the SuppVersity Science Round Up on Super Human Radio(click here to download the podcast), but if you were, you may have made the same observation I did: Whenever you feel that you got more than enough time to get a task done or, in this case, a list of topics discussed, you start loiter, to go on tangents and to end up in interesting, yet in the end "off-topic" discussions about all and sundry or "Gott und die Welt" as people in Germany woul say (literally translated: "God and the world").

Personally, I enjoyed the less packed format of yesterday's show, though. What about you? Shall we aim to discuss less news items in the future and thus have time to discuss those we picked in more detail or do you prefer the classic "short" over the long version?
I guess these were more than enough questions for a single installment of the Seconds now and you are starving for the news items that did not make it into yesterday's show. Well, let's see what we've got here, then:

Tan Yourself into the >75nmol Range For Vitamin D 

Actually it is obvious that it should be possible to use a tanning bed (in the study at hand a type 3 sunbed w/ 2,15% UVB: 280-320nm; note: as Tim informed me in the comment area most sunbeds in the EU have max. 1% UVB, so you better make sure what type you are using) to boost and keep your vitamin D levels in the >75nmol range, of which current research suggests that this is where the magic happens (click here learn more also about Vitamin D and my own skepticism towards the "vitamin D solves all your problems" hype).

Figure 1: Graphical outline of the cross over design (Lagunova. 2013)

The same thought obviously occurred to a group of scientists from Norway, where the latitude, respectively the incidence angle of radiation and the scattering of short wave radiation in the atmosphere allows for effective vitamin D synthesis only in the summer months from April to October. To find out how long you'd have to stay on the "Asitoaster" (an only in some cases inappropriate derogative German term for the "sunbed", which denotes that only the less educated lower class uses the regularly) the scientists recruited 31 healthy Oslo (59°N) residents. The men and women were 23-61 and only one of them had already 25OHD levels in the >75nmol/L range.

As the graphical outline (see figure 1) of the study protocol goes to show you, the 8 men and 23 women were assigned to two different groups. Both groups underwent both the tanning bed, as well as the vitamin D3 supplement intervention (cross over design) with the only difference being that one group started out taking 2,000IU vitamin D (Carlson's brand), while group II jumped right onto the tanning bed, ...

...well, actually no one "jumped right onto the tanning bed"

For both groups the tanning bed intervention had a similar built-in progression as you would expect it from any beginner workout: Starting with a weekly exposure of 2 x 1-1.3 SED (7 min; this is what even the most fairly skinned individuals can do), the subject slowly accustomed their body to the radiation by extending their stay on the tanning bed to 1.9 SED (10 min) in weeks 2 + 3 over 2.4 SED (13 min; warning: according to Fitzpatrick et al. "light tanned" people with a greater risk of developing skin cancer can get a sunburn from this dose already; Fitzpatrick. 1995) in weeks 4 + 5 to a maximal exposure of 2.8 SED (15 min) in weeks 6-10.

Figure 2: Serum vitamin D (25OHD) levels during the supplementation / tanning bed phase in the two arms of the study (Lagunova. 2013)

As the data in figure 2 goes to show you, both protocols were equally effective in building and + or maintaining vitamin D levels in the >75nmol/L range.

In case you missed yesterday's "True or False" click here to learn whether or not you have to take your D3 supps with fatty foods.

For "the average" study participant that was a >40% increase over baseline, for the 9 volunteers who began with baseline vitamin D levels below the 50nmol/L margin, the increase was correspondingly higher.

The scientists do therefore have good reason to head the manuscript of their soon-to-be-published study with the following statement about what the study adds to our knowledge about the relative efficiency of supplemental and natural vitamin D sources, with respect to efficiency to increase serum 25-hydroxyvitamin:

"Two weekly whole body UV exposures to a total dose of 4.8 SED for 5 weeks to a total dose of  23.8 SED are equal to 2000 IU/d of oral vitamin D supplementation for 30 days and enough to achieve and maintain serum 25(OH)D concentrations above 75 nmol/L in ~ 55% of the cases." (Lagunova. 2013).

In the end, it does therefore not appear to matter, whether you take the natural or supplemental approach to keep your vitamin D levels in the upper tertile of the (revised) normal range - personally I would yet prefer the ultra-natural route (at least for the summer months).

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Bottom line: There is little to add to the title of another recently published study "Make Vitamin D While the Sun Shines, Take Supplements When It Doesn't". Although,... when I come to thing about it, I guess there still is one thing to add: Don't be too cheap to test where you're at!

Additional news and follow ups

• Can you add 9.4 years to your live by following a low GI diet? Maybe... at least if the recent data from a rodent study that was conducted at the School of Medicine of the Deakin University in Geelong (Australia) would translate to human beings (Nankervis. 2013). Especially in those of us (or the others) who still live on the garbage that's called food, when it's part of the standard American diet, I am yet pretty confident that it would.
  
  Over the course of their 24-months experiment the scientists had provided their mice with either the normal rodent chow or (GI 70) or a low GI alternative (GI 27), did a whole series and tests and waited for the animals to pass away.

  Figure 3: Relative telomere length of the mice and diet composition (Nankervis. 2013)

  Much to my personal surprise this one set-screw (=low GI diet) was potent enough to extend the average lifespan by 12%.
  
  

  I doubt it's a coincidence that the purported telomerase activator Astragalus is also a potent anti-diabetic and anti-inflamatory - in the end glycemia and inflammation are the determinants of longevity, telomerase length only an indicator (learn more)

  If we take into consideration that the life-expectancy of the average American is 78.7 years (CDC. 2013), this would mean that he / she would live almost 10 years longer if he simply stayed away from all the processed junk to reduce the average GI of his / her diet to the sub 30pts region.
  
  And while it is probably not even necessary to say that this increased life-expectancy went hand in hand with improved glucose tolerance up into the old age and an "impressive [...] amelioration of oxidative damage to DNA in white blood cells." (Nankervis. 2013), it is imho important to point out that this longevity bonus came in the absence of improved telomere lengths in quadriceps muscle and/or the reactivation of telomerase.
  

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  Bottom line: Contrary to overpriced and from a science perspective highly questionable "telomerase promoters"  a simple reduction of the sugary onslaught on your metabolism will not just improve some exotic markers of which we still don't know exactly how they figure in the aging process, but actually extend the life of a relatively complex species. How beneficial a similar dietary protocol would be in humans

• Pre- or post-menopausal, Drinking coffee, tea or cacao could protect you from breast cancer (learn more)

  Estrogen therapy for women -- Everyone who's following the SuppVersity Facebook news closely, will probably remember my recent post on the latest scientific spin-off from the Women's Health Initiative (WHI) dataset which suggests that the combination treatment of estrogen + artificial progesterone (=progestin) was associated with a 55%+ higher risk of breast cancer. Even more when the drug treatment was initiated in the early phase of menopause (Chlebowski. 2013). Against that background.
  
  And as if that was not enough, the same wicked drug cocktail (equine estrogen + progestin) has also been shown to increase the risk of dementia, although you would expect that ERT (estrogen replacement therapy) should do the opposite (Shumaker. 2003).
  
  Way before the publication of the troublesome data from the large scale WHI study, the perspective on HRT for women has been changing, with the current concept suggesting that estrogen plus progestin useincreases breast cancer risk and the effect on risk may be greater in women who initiate therapy closer to menopause, broadly increases breast cancer risk with the increase in risk not limited to hormone receptor–positive cancer, interferes with breast cancer mammographic detection resulting in cancers diagnosed at more advanced stage and increases breast cancer mortality. Estrogen only use on the other hand is currently understood to reduce breast cancer risk and does not interfere with breast cancer detection by mammography (cf. Chlebowsky. 2012).
  

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  Bottom line:If you consider hormone therapy ladies, don't let your Dr. tell you that the "new" (when he went to medical school) estrogen + progestin drugs were the way to go.

• Figure 4: Relative magnesium absorption and retention in black and white girls (11–15 y old) after 3 weeks on a high sodium diet (3.8 g/d); neither calcium intake nor vitamin D levels influenced the detrimental effects of the high sodium diet (Palacios. 2013)

  Too much NaCl or too little Mg is that the question? It actually could be the question, after all a recent study from the School of Public Health at the University of Puerto Rico would suggest that magnesium deficiency, which is in and out of itself associated with most if not all the bad things salt is usually blamed can come about much easier if you consume a high salt diet.
  
  As the data in figure 4 goes to show you, the amount of magnesium that's actually retained (not the amount you absorb!) is reduced by 33%, when the salt intake approaches the 4g/day mark. With a dietary intake of ca. 230mg/day (RDA for 11-15y old girls) the participants were "grams away" of a daily intake level that would require the body to get rid of excess magnesium.
  

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  Bottom line: If you don't eat processed foods, you are not really at risk of getting too much NaCl or too little magnesium. Plus, as an aspiring physical culturist you lose tons salt, but almost no magnesium (the NaCl:Mg ratio in sweat is >682:1; cf. Montain. 2007) with your sweat, but don't we all have friends and family who are still pretty "average"? Well, in that case you already have a present for them: 1-2lbs of cheap magnesium citrate powder... but beware, never use this as a birthday, anniversary or Valentin's present for your significant other ;-)

Actually I could go on forever with notes on stuff Carl and I have been talking about, but you would not be interested in it anyways, right? Plus, let's be honest if you have listened to the podcast, read and digested the Seconds it's about time for some Intermittent SuppVersity Fasting. You know the whole thing about the cyclicity of life? This is not much different with the latest science news: If you were not forced to be without them for some time, you would lose sight of how extraordinary the daily SuppVersity news actually are ;-)

References:

• CDC. FastStats - Life Expectancy. March 04 2013. < http://www.cdc.gov/nchs/fastats/lifexpec.htm > retrieved on April 11, 2013. 
• Chlebowski RT, Manson JE, Anderson GL, Cauley JA, Aragaki AK, Stefanick ML, Lane DS, Johnson KC, Wactawski-Wende J, Chen C, Qi L, Yasmeen S, Newcomb PA, Prentice RL. Estrogen Plus Progestin and Breast Cancer Incidence and Mortality in the Women's Health Initiative Observational Study. J Natl Cancer Inst. 2013 Mar 29.
• Chlebowski RT, Anderson GL. Changing concepts: Menopausal hormone therapy and breast cancer. J Natl Cancer Inst. 2012 Apr 4;104(7):517-27.
• Fitzpatrick TB, Cesarini JP, Young A, Kollias N, Pathak MA. Reported in Fitzpatrick TB, Bolognia JL. Human melanin pigmentation: Role in pathogenesis of cutaneous melanoma. In: Zeise L, Chedekel MR, Fitzpatrick B, eds. Melanin: Its Role in Human Photoprotection. Overland Park, KS: Val-denmarPublishing Co; 1995: 177-182.
• Lagunova Z, Porojnicu AC, Aksnes L, Holick MF, Iani V, Bruland OS, Moan J. Effect of vitamin D supplementation and ultraviolet B exposure on serum 25-hydroxyvitamin D concentrations in healthy volunteers: a randomized, crossover clinical trial. Br J Dermatol. 2013 Apr 1.
• Montain SJ, Cheuvront SN, Lukaski HC. Sweat mineral-element responses during 7 h of exercise-heat stress. Int J Sport Nutr Exerc Metab. 2007 Dec;17(6):574-82.
• Nankervis SA, Mitchell JM, Charchar FJ, McGlynn MA, Lewandowski PA. Consumption of a low glycaemic index diet in late life extends lifespan of Balb/c mice with differential effects on DNA damage.  Longevity & Healthspan. 2013; 2(4).
• Palacios C, Wigertz K, Braun M, Martin BR, McCabe GP, McCabe L, Pratt JH, Peacock M, Weaver CM. Magnesium retention from metabolic-balance studies in female adolescents: impact of race, dietary salt, and calcium. Am J Clin Nutr. 2013 Apr 3.
• Pittaway JK, Ahuja KD, Beckett JM, Bird ML, Robertson IK, Ball MJ. Make Vitamin D While the Sun Shines, Take Supplements When It Doesn't: A Longitudinal, Observational Study of Older Adults in Tasmania, Australia. PLoS One. 2013;8(3):e59063. 
• Shumaker SA, Legault C, Rapp SR, Thal L, Wallace RB, Ockene JK, Hendrix SL, Jones BN 3rd, Assaf AR, Jackson RD, Kotchen JM, Wassertheil-Smoller S, Wactawski-Wende J; WHIMS Investigators. Estrogen plus progestin and the incidence of dementia and mild cognitive impairment in postmenopausal women: the Women's Health Initiative Memory Study: a randomized controlled trial. JAMA. 2003 May 28;289(20):2651-62.