Saturday, March 30, 2013

No DHA & EPA in Non-Fish Fed Catfish. No Recovery From Ischemia W/ Low Carb. No Endocannabinoid Effects Without Medium Intensity Exercise. No Need to Tow Only Light Sleds

Sarah Reinertsen (click here to visit her webpage) was the first female leg amputee to participate and complete the Ironman (in 15h) and I bet she does not need the recent study by Galy et al. to be reminded of the benefits... no, the necessity of cycling your exercise intensity.
In 2005 Sarah Reinertsen (image on the right) was the first female leg amputee to participate and complete the Ironman and honestly this would probably suffice as a figure of the week, but since this is a historic event, it does not necessarily qualify as the SuppVersity Figure of the Week.

A figure that does qualify is the -15.7% decrease in post-exercise alveolar-capillary membrane diffusing capacity the highly trained triathletes in a soon-to-be-published paper by Galy et al. experienced after a 6-week "deload" (low training volume, intensity and frequency) period. What's interesting, though, is that the control group who remained on the same high training volume, intensity and frequency conditioning program all athletes had followed for the previous 30-weeks showed a similar, but less pronounced decrease in this measure of the diffusing capacity of oxygen and carbon dioxide between the lungs and the blood (-9.3%; Galy. 2013). This goes to show you that avoiding periods of lighter training in fear of the potential negative effects on your performance is no solution (learn more about detraining & co)

Only fillets from "fish-fed catfish" are worth your money

(Faukner. 2013) -- Feeding fish fish oil yields the highest concentration of omega-3 fatty acids in filets. That's the very unspectacular result of a recent study by scientists from the Department of Aquaculture and Fisheries at the University of Arkansas at Pine Bluff. The main reason I still mention it is that feeding the catfish a diet that was "enhanced" with soybean oil, as it is common practice to increase the weight gain of the fish, yielded fillets with exactly zero DHA & EPA and a 3x lower total omega-3 to omega-6 ratio. 
Total n-3 & n-6 PUFA content (in % of total fat in the filets) and long-chain PUFA content (in % of PUFA content) + tabular overview of the fatty acid composition of the fillets from catfish on standard diet or diets supplemented with 2% additional fat from soy oil (SO), soy oil enhanced with CLAs (CLA), an algal source of DHA
(Schizochytrium sp.) combined with soybean oil, and refined fish oil (FO; Faukner. 2013)
Now you got to bear in mind that the latter figure includes the short-chain omega-3s which do not display the same health benefits as their long-chain cousins DHA & EPA. If we look strictly at these long-chains, the comparison would yield an n3/n-6 ratio that is at least 120x higher for the fish oil enriched diet (this is based on the assumption that the test had an accuracy of .01% n-3-LC-PUFA / % total fat)... ah, and in case you want CLA in your fish, you better make sure that it is part of the feed, 'cause fish quite obviously don't produce any of these omega-6 trans-fats in their tiny guts (soy-fed or not ;-).

High fat + low carb not the way to go after ischemic heart disease

(Liu. 2013) -- Despite the fact that the scientists from the University of Alabama at Birmingham obviously could not find human volunteers to participate in a controlled study into the effects of low carbohydrate (<10%) + high fat (60%; equal parts from milk fat, lard and vegetable oils) on the recovery of cardiac function after ischemia and reperfusion. The data the scientists gathered in a rodent study clearly suggests: High fat low carb diets are more than sub-optimal right after heart ischemic events.

Diet dependent expression of selected antioxidant enzymes and determinants of mitochondrial biogenesis on day 3 after heart ischemic events in overweight Sprague Dawley rats (Liu. 2013)
Compared to the obese rats in the control groups those being fat a high fat low carbohydrate diet (10%) after an experimentally induced ischemic episode of the heart (low blood / oxygen supply) showed increased ischemic myocardial injury and impaired recovery of function after reperfusion. Moroever, the low carb diet was associated with an attenuation of mitochondrial biogenesis and enhanced oxidative stress in the obese lab animals. And while it will still have to be seen, whether the same negative effects would occur in non-obese rodents, the majority of patients who are treated for ischemic heart disease have at least a couple of pounds too much on their waistline, so that "these findings may [in fact] have important implications for diet selection" (Liu. 2013) for the majority of patients with ischemic heart disease.

Addendum: Just a note on the "must be the omega-6 hypothesis" you are just pondering (a) the ratio of "bad" vegetable oils was as mentioned before 1/3 (the rest was lard and milk fat), (b) there is no chance you blame the observed effects on the "bad" omega-6s, alone, simply because they, or rather the long-chain n-6 PUFA arachidonic acid is a ligand to the PPAR-delta receptor and the latter is responsible for the health of the mitochondria in your heart including the mitochondrial DNA copy number (Wang. 2010)

Endocannabinoid modulation is a prerogative of moderate intensity exercise

Effect of treadmill running at different heart rates on the level of anandamide one of the major and best studied endocannabinoids (Raichlen. 2013)
(Raichlen. 2013) -. Despite all the advantages of high intensity interval training over classic moderate steady state cardio, the latter still yields surprisingly beneficial results especially in those trainees who still carry large amounts of body fat, are insulin resistant, inflamed or suffer from other metabolic derangements. In addition to that there is overwhelming evidence for the beneficial effects this type of exercise has on the psyche and overall cognitive health. A recent study from the School of Anthropology at the University of Arizona in Tucson suggests that this could be result of their ability to restore normal endocannaboid function and thus yield both physiological and psychological benefits (e.g restoration of the reward system, learn more; Glass. 1997).

Now this certainly doesn't mean that you should all of a sudden give up on high intensity exercise completely, after all Rakobowchuk et al. have just demonstrated that HIIT training (learn how it works) will not just improve your aerobic capacity, it will also decrease arterial stiffness and optimize heart rate dynamics (Rakobowchuk. 2013).  The results of the Raichlen study should however remind you that working out is exactly like dieting. Training and eating too single-sided is at least sub-optimal in most cases even detrimental.

Huskies will prevail: Heavy sled towing is way more effective than light sled towing

(Kawamori. 2013) -- Huskies will prevail: Heavy sled towing is way more effective than the widely recommended light load sled towing, where the weight of the weight will slow you down by only 10%. That's the result of a recent study from the School of Exercise and Health Sciences at the Edith Cowan University in Joondalup, Western Australia.
Outline of the training protocol used in the study. The groups differed only in the weight that was used on the sled to elicit a slow down of 10% (light group) and 30% (heavy group), respectively. All subjects trained twice per week.
After training with a sled that decreased the velocity by 30% and would thus be three times to heavy (according to the prevalent notion that 10% was best) the 10 physically active men who had been allocated to the heavy (=30% slow down) group increased both their 5- and 10-m sprint time by 5.7 ± 5.7% and 5.0 ± 3.5%, respectively (P < 0.05). The 11 subjects in the light sled (=10% slow down) group, on the other had increased only their 10-m sprint time and this increase was 2% lower than the one observed after heavy sled towing.



That's it for today's installment of On Short Notice! I hope you are all enjoying the Easter weekend and that irrespective of whether this is or isn't a holiday in the the original sense for you, or not. And in case you ever feel the urgent desire to get up to speed with what's going on in the world of exercise, nutrition and supplementation science before the next SuppVersity post hits the Net, feel free to visit the SuppVersity Facebook wall.


References:
  • Faukner J, Rawles SD, Proctor A, Sink TD, Chen R, Philips H, Lochmann RT. The Effects of Diets Containing Standard Soybean Oil, Soybean Oil Enhanced with Conjugated Linoleic Acids, Menhaden Fish Oil, or an Algal Docosahexaenoic Acid Supplement on Channel Catfish Performance, Body Composition, Sensory Evaluation, and Storage Characteristics. North American Journal of Aquaculture. 2013; 75(2). 
  • Galy O, Maimoun L, Coste O, Manetta J, Boussana A, Préfaut C, Hue O. 6 Weeks of Low Volume, Low Intensity Training Aggravate Pulmonary Diffusing Capacity in Highly Trained Athletes. Int J Sports Physiol Perform. 2013 Mar 26.
  • Glass M, Dragunow M, Faull RLM. Cannabinoid receptors in the human brain: a detailed anatomical and quantitative autoradiographic study in the fetal, neonatal and adult human brain. Neuroscience. 1997; 10:1665–1669
  • Liu J, Lloyd SG. High-fat, low-carbohydrate diet alters myocardial oxidative stress and impairs recovery of cardiac function after ischemia and reperfusion in obese rats. Nutrition Research. March 26, 2013 [Epub ahead of print].
  • Kawamori N, Newton RU, Hori N, Nosaka K. Effects of weighted sled towing with heavy versus light load on sprint acceleration ability. J Strength Cond Res. 2013 Mar 27. 
  • Rakobowchuk M, Harris E, Taylor A, Cubbon RM, Birch KM. Moderate and heavy metabolic stress interval training improve arterial stiffness and heart rate dynamics in humans. Eur J Appl Physiol. 2013 Apr;113(4):839-49.
  • Raichlen DA, Foster AD, Seillier A, Giuffrida A, Gerdeman GL. Exercise-induced endocannabinoid signaling is modulated by intensity. Eur J Appl Physiol. 2013 Apr;113(4):869-75.
  • Wang P, Liu J, Li Y, Wu S, Luo J, Yang H, Subbiah R, Chatham J, Zhelyabovska O, Yang Q. Peroxisome proliferator-activated receptor {delta} is an essential transcriptional regulator for mitochondrial protection and biogenesis in adult heart. Circ Res. 2010 Mar 19;106(5):911-9.