Sleep Apnea and Insulin Sensitivity

This is some pretty old research but it's really unique and I thought I'd share it for any of our readers with sleep apnea.

Continuous Positive Airway Pressure Treatment Rapidly Improves Insulin Sensitivity in Patients with Obstructive Sleep Apnea Syndrome

Igor A. Harsch, Simin Pour Schahin, Martin Radespiel-Tröger, Oliver Weintz, Holger Jahreiß, Florian S. Fuchs, Gunther H. Wiest, Eckhart G. Hahn, Tobias Lohmann, Peter C. Konturek and Joachim H. Ficker Department of Medicine I; Department of Medical Informatics, Biometrics, and Epidemiology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen; Department of Medicine 3, Klinikum Nürnberg, Nuremberg, Germany The obstructive sleep apnea syndrome is typically associated with conditions known to increase insulin resistance as hypertension, obesity, and diabetes. We investigated whether obstructive sleep apnea itself is an independent risk factor for increased insulin resistance and whether continuous positive airway pressure (CPAP) treatment improves insulin sensitivity. Forty patients (apnea–hypopnea index > 20) were treated with CPAP. Before, 2 days after, and after 3 months of effective CPAP treatment, hyperinsulinemic euglycemic clamp studies were performed. Insulin sensitivity significantly increased after 2 days (5.75 ± 4.20 baseline versus 6.79 ± 4.91 µmol/kg · min; p = 0.003) and remained stable after 3 months of treatment. The improvement in insulin sensitivity after 2 days was much greater in patients with a body mass index less than 30 kg/m2 than in more obese patients. The improved insulin sensitivity after 2 nights of treatment may reflect a decreasing sympathetic activity, indicating that sleep apnea is an independent risk factor for increased insulin resistance. The effect of CPAP on insulin sensitivity is smaller in obese patients than in nonobese patients, suggesting that in obese individuals insulin sensitivity is mainly determined by obesity and, to a smaller extent, by sleep apnea.

Tryptophan ingestion and Circadian Rhythm

Speaking of Circadian Rhythm,

Take your tryptophan at 7pm.



1: Basic Clin Pharmacol Toxicol. 2009 Jan;104(1):52-59.
Circadian Levels of Serotonin in Plasma and Brain after Oral Administration of Tryptophan in Rats.

Mateos SS, Sánchez CL, Paredes SD, Barriga C, Rodríguez AB.
Department of Physiology, Neuroimmunophysiology Research Group, Faculty of Science, University of Extremadura, Badajoz, Spain.
: Serotonin, one of the most important neurotransmitters in the central nervous system, is synthesized by the amino acid, tryptophan. Given that this essential amino acid is consumed in the diet, the aim of this study was to evaluate the effect of orally administered L-tryptophan (125 mg/kg) on circadian variations in the levels of serotonin in brain and plasma. We used male Wistar rats of 14 +/- 2 weeks of age (n = 240), maintained under conditions of a 12-hr light:dark cycle, and food and water ad libitum. Tryptophan administration was by gavage in a daily single dose at 7 p.m. for 7 days. The serotonin levels were measured by ELISA every hour at night (8 p.m. to 8 a.m.) and every 4 hr during daytime (8 a.m. to 8 p.m.). The results show that in both the tryptophan-treated and untreated groups the highest values appeared during the beginning of the darkness with a peak at 9, 10 and 11 p.m. in controls, and at 9 p.m. in the tryptophan-treated group. After tryptophan administration, the levels of serotonin were significantly higher in the plasma and all the brain regions analysed than in the control group. This increase of serotonin levels was greater in the pineal gland than in other brain regions, and the least in plasma. In conclusion, oral administration of tryptophan during 7 days enhances serotonin levels over a 24-hr period, and produces an advance in the peak of serotonin in both plasma and different brain regions.
PMID: 19152552 [PubMed - as supplied by publisher]

Low-Carbohydrate Diet Burns Excess Liver Fat

Low-carbohydrate diet burns more excess liver fat than low-calorie diet, UT Southwestern study finds

We all probably already know by now that people on a low carb (LC) diet rely mostly on fats to produce energy. When our body is denied glucose our body can create ketones in order to continue it's biological imperatives of eating sleeping and well, ehem...

One thing that wasn't sure up until now was whether or not the body, when in a low carb state, would burn excess amounts of fat deposited in the liver. Fatty Liver is a serious disease that millions of americans are affected with. It seems that an already solid diet strategy just got more awesome:

DALLAS – Jan. 20, 2009 – People on low-carbohydrate diets are more dependent on the oxidation of fat in the liver for energy than those on a low-calorie diet, researchers at UT Southwestern Medical Center have found in a small clinical study.

The findings, published in the journal Hepatology, could have implications for treating obesity and related diseases such as diabetes, insulin resistance and nonalcoholic fatty liver disease, said Dr. Jeffrey Browning, assistant professor in the UT Southwestern Advanced Imaging Research Center and of internal medicine at the medical center.

"Instead of looking at drugs to combat obesity and the diseases that stem from it, maybe optimizing diet can not only manage and treat these diseases, but also prevent them," said Dr. Browning, the study's lead author.

(My Comments) Well, um... Yeah. I've been saying this for a long time now, and so have many others, but it seems that the old regime takes some time to fall. A sensible Low Carb Diet is essentially a CURE or PREVENTATIVE solution to almost every disease we are struggling with today. Why? Not because it's some revolutionary way to live. It's because Low Carb is HOW WE ARE SUPPOSED TO EAT. It's how man (and their better half) had been eating for the past 190,000 years (before the last 10,000 following things like the agricultural revolution.

I try not to get preachy but this scientific revelation along with most of the others regarding low carb is tantamount to people saying not eating leads to starvation so perhaps we should eat.

Ehem....

Although the study was not designed to determine which diet was more effective for losing weight, the average weight loss for the low-calorie dieters was about 5 pounds after two weeks, while the low-carbohydrate dieters lost about 9½ pounds on average.

Well I will at least admit that a good three pounds of that weight loss in the LC group is probably attributable to decreased water retention. Carbohydrates tend to draw water into the body so when you stop consuming as much of them you will lose three or four pounds just from that change, but it is just water.

The different diets produced other differences in glucose metabolism. For example, people on a low-calorie diet got about 40 percent of their glucose from glycogen, which is comes from ingested carbohydrates and is stored in the liver until the body needs it.

The low-carbohydrate dieters, however, got only 20 percent of their glucose from glycogen. Instead of dipping into their reserve of glycogen, these subjects burned liver fat for energy.

Now this is really good news to athletes. It seems that even during an LC diet we can hold on to our glycogen for when we really need it like sprinting or other anaerobic movements.

Bottom line - Low Carb is winning every race.






This news release is available at http://www.utsouthwestern.edu/home/news/index.html

Speaking of melatonin

http://www.ncbi.nlm.nih.gov/pubmed/18782656?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum


A very well known but consistently noticable side effects of aromatase inhibition is joint stiffness. Everyone from men who want to lower estrogen to women who are treating breast cancer have complained of this side effect and it may be that melatonin is involved in this process. Why? Well apparently this reduction of estrogen (by inhibiting an enzyme that converts hormones into estrogen) affects our pineal gland's ability to suppress melatonin (the pineal gland is responsible for melatonin release and suppression) during the day. The take home message? Get more sunlight during the day if you're using things to suppress estrogen. This doesn't mean you need to get a tan but it does mean getting away from the computer for a minute and enjoying more time outside, provided it's not dark and rainy... Or you can do what they did in the study

If worn first thing in the morning, the cap sharply curtailed the duration of morning stiffness. If worn for a sufficient number of hours during the day, the cap suppressed symptoms the next morning, just as sunlight did. Because of evidence for melatonin's oncostatic properties, this hypothesis potentially has implications beyond decreasing the number of patients that discontinue AIs. It may be that some portion of the survival benefit of AIs is due to their indirect effect on melatonin, not just their direct effect on estrogen.

Beyond that it is simply more information helping us to better understand just how intricately all hormones and peptides in the body are interlaced in their physiological effects. As well it also might be giving us further information about how melatonin can actually be a powerful anti-cancer agent. There are some that hypothesize melatonin given in large amounts can suppress cancer in the body. It may very well be that aromatase inhibiting drugs used to lower estrogen in women may actually provide an indirect anti-cancer effect by increasing melatonin production all day.

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Now back to your regularly scheduled self-enhancement exploration

Sleep/Wake Rhythm and Diabetes

We've been discussing for years now at http://www.alphachakra.com the implications of maintaining a healthy circadian rhythm. Some of us have been diligent in our efforts by limiting light after 8pm and being in bed by 10 while some of us have simply been engaged in research and discussion. The bottom line though seems to be the human body was designed to live in this rhythm and we're now finding out that even things like diabetes have links to dysregulation of our circadian rhythm.

http://www.helmholtz-muenchen.de/en/press/press-releases/press-releases-2009/press-releases-2009-detail/article/11503/44/index.html

Specifically there is a new gene variant recently discovered which has to do with melatonin AND insulin. This is the first time I've seen the two mentioned together but it would make sense since it's at night that we tend to be producing less insulin, that is unless we are busy snacking, which could be explained as well as addressed by our own messed up internal clocks.

From the article

"The gene mediates insulin secretion indirectly via the release of melatonin, which implicates a previously unknown relationship between the sleep-wake rhythm and the fasting glucose level. The finding could open up new possibilities of treatment which go far beyond the primarily symptomatic therapy approaches to diabetes that have been practised until now."

The article goes on to discuss this gene, the MTNR1B gene and explains that they have found the islet cells (insulin producing cells) in the pancreas have receptors for melatonin. Activation of these receptors by melatonin seem to inhibit the release of insulin!

This may even prove to be useful at some point for the treatment of hyperinsulinemia, or the overproduction of insulin. In the meantime the take home message to me is to get my own inner timeclock ticking in a natural rhythm through adjustments of sleep schedule and limiting light in the evening hours. When all else fails I'd recommend a melatonin product, preferably sublinqual so as to facilitate absorption. http://www.iherb.com/ProductDetails.aspx?pid=1322&at=0