High(er) Dose Fish Oil (3g EPA+DHA per Day), an Effective Thermogenic for Older Women - 187 kcal/Day Higher RMR

High(er) Dose Fish Oil (3g EPA+DHA per Day), an Effective Thermogenic for Older Women - 187 kcal/Day Higher RMR

basal metabolic rate DHA elderly energy expenditure EPA fat oxidation fish oil lose fat metabolic rate older women RMR women

This study is different from the average "fish oil is good for you" study and that's both refreshing and revealing. Speaking of "fresh" you got a 50/50 chance you buy fresh, not rancid fish oil.

I am not exactly a fan of fish oil supplementation, but I am neither ignoring the few gems among the bazillion of "fish oil is good for you" papers. Samantha L. Logan's and Lawrence L. Spriet's latest paper in the open access journal PLOS|ONE looks as if it was one of those gems. A gem that suggests that 3g of DHA + EPA per day (2 g/d EPA, 1 g/d DHA, to be precise) will not just lower the triglyceride levels of community dwelling older, healthy women by 29%, but also (a) increase their lean mass by 4%, (b) boost their functional capacity by 7% and (c) bump up their resting metabolic rate by 14%, their energy expenditure during exercise by 10%, and the rate of fat oxidation during rest and low-intensity cycling by 19% and 27%, respectively.

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What? Yep, now I got your attention, right? Well, the objective of the study was to evaluate the effect of fish oil (FO) supplementation in a cohort of healthy, community-dwelling older females. Now, in contrast to your average fish oil study, the scientists did not restrict themselves to measuring the effects on blood measures of insulin, glucose, c-reactive protein, and triglycerides, though. Their primary study outcomes included the effects on the subjects' metabolic rate and substrate oxidation at rest and during exercise as well as on body composition, strength and physical function.

For the study, twenty-four healthy females (66 ± 1 yr) were recruited and randomly assigned to receive either 3g/d of EPA and DHA or a placebo (PL, olive oil) for 12 wk. Exercise measurements
were taken before and after 12 wk of supplementation and resting metabolic measures were made before and at 6 and 12 wk of supplementation.

Figure 1: Relative changes in metabolic parameters at rest and during 30 min of exercise (Logan. 2015).

As you already know and can now see in Figure 1, the fish oil supplementation significantly increased the subjects' resting metabolic rates, energy expenditure during exercise and the rate of fat oxidation at rest and during exercise. What is kind of funny, though, is that the scientists either misreported the actual values or miscalculated the changes, because I used the data from their study to calculate the relative differences in Figure 1 and as you can easily see those are significantly different from the values reported in the introduction - values I copied directly from the abstract.

So, how did this work? As of now we don't really know that. It is most likely that EPA and DHA modulate energy metabolism by activating one or several PPAR receptors, which may then trigger increases in the levels several protein (FAT/CD36, FABPc, UPC3) and enzymes (acyl-CoA oxidase, CPTI) which control the mitochondrial fatty acid oxidation. Additional effects on PGC-1α, which is involved in regulating the genes involved in energy metabolism, as well as in mitochondrial biogenesis and function may augment the metabolic effects of the long-chain omega-3s. Effects of which we do yet not know how they are affected by and whether they require the incorporation of DHA and EPA into the cell membrane - obviously significantly more research is necessary.

Now the reason I am not going to spend time to find out, whether I or the researchers have made a mistake is that the statistically significant increase in resting metabolic rate for example amounts to 7kcal per hour, if the actual value is 2-5% lower or higher that's absolutely irrelevant. Since the same can be said for the other values, I think we all should be able to cope with any potential deviation from the actual data in the following overview I've compiled based on the (hopefully accurate) data from the tables in the full text of the study graphically in Figure 2.

Figure 2: Graphical overview of the absolute increase in energy expenditure and fat oxidation (Logan. 2015).

In conjunction with the marginal, but significant increase in lean mass, which does by the way only partially explain the increase in energy expenditure, these changes are not just statistically, but practically relevant - that's something even I, as a fish oil critic, have to admit ;-)

So, fish oil is a metbalic activator? Well, at least in this particular group of subjects, there's no debating that the 3g of combined EPA + DHA per day triggered statistically significant and as the data in Figure 2 shows even potentially practically relevant increases in energy expenditure at rest and during exercise.

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As the authors highlight, though, "[f]uture research should also aim to test a greater number of participants and include a longer period of supplementation (ie. 1 yr) to determine whether the increase in metabolic rate results in changes in more robust changes in body composition" (Logan. 2015). In view of the complaints of their subjects who had difficulties stomaching the 5g of total fish oil that were required to achieve the desired dose of EPA + DHA, the scientists also argue that future studies have to investigate solutions that reduce the digestive issues (gastrointestinal discomfort) and whether you even need 3g of EPA + DHA or lower dosages would have the same effect... well, and obviously, it would be interesting to see if similar results could be observed in younger and / or male subjects | Comment on Facebook!

References:

• Logan, Samantha Louise. Physical Activity and Nutrition as Modifiable Lifestyle Factors for Healthy Aging in Older Adults. Diss. The University of Guelph, 2013.

Caffeine + Green Tea = Plus 10% Fat Oxidation & Energy Expenditure at Rest and During Sprint Interval Exercise

Caffeine + Green Tea = Plus 10% Fat Oxidation & Energy Expenditure at Rest and During Sprint Interval Exercise

caffeine coffee EGCG energy expenditure fat burner fat oxidation green tea GTE lose fat metabolic rate REE

From a health perspective it may be good that green tea does not contain all-too much caffeine. From a fat loss perspective, it clearly lacks caffeine.

When it comes to dietary supplements, people like to pay tons of money for unproven ingredients with funky names and dubious or non-existent safety profiles; agents that have been scientifically proven to work, are safe and cheap, on the other hand, are non-sellers or at least considered to be non-effective.

Obviously, I cannot really explain why that is the case (I suspect it is because people effect drug-like effects without drug-like side-effects from supps and are thus always on the lookout for the "next big"... hoax), I can tell you, though, that a recent study that is going to be published in one of the upcoming issues of the Journal of Strength and Conditioning Research (Jo. 2015) shows that caffeine and green tea, two supplements that belong to the previously described category, are everything but useless.

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In said study, Edward Jo and colleagues investigated the effects of a caffeine + green tea polyphenol mix (250mg caffeine + 400mg of a green tea extract with 50% EGCG and 5mg of caffeine per serving) on (a) metabolic rate and fat oxidation at rest, as well as following a bout of sprint interval exercise (SIE) and (b) the performance during a standardized sprint-interval test.

The study was a double-blind, randomized, placebo-controlled, crossover study that involvd 12 subjects (male: n=11; female:1 n=1) whose antroprometric data, i.e "body mass=76.1±2.2 kg; height= 169.8±1.6 cm; BMI= 22.7±3.0 kg/m2; body fat %= 21.6±2.0% [DXA data]" (Jo. 2015), already tell you that they were healthy recreationally active, but not necessarily athletic (it may be worth mentioning that they were relatively stim-naive with an intake of < 201mg of caffeine per day).

Figure 1: Energy expenditure (kcal/h) and fat oxidation (g/day) measure before (at rest) and during (during SIE) the sprint interval exercise 10 and 55 minutes after the ingestion of caffeine + GTE or placebo (Jo. 2015).

During the two testing sessions at the Human Performance Research Laboratory of the California State Polytechnic University, the subjects' resting energy expenditure (REE) was measured for 45 minutes starting 10 minutes after the ingestion of the aforementioned caffeine + polyphenol mix - a mix that was consumed on an empty stomach after an 8-h overnight fast (don't be fooled by the way the scientists report their data in "g/day" and kcal/day - I changed the latter, already but the values for fat in g would have become to small - we are talking about 45 + 30 min and a 24h measurement here).

Don't confuse increases in fat oxidation w/ fat loss: I guess we have to credit the supplement industry for propagating the myth that the ratio of fat to glucose you were burning was in anyway directly related to losing body fat. I am not sure how often I've written this on this blog or told someone in the gym: that is not the case. You can burn 20% more fat and still store more body fat if you increase your energy intake from exactly enough to already too much. The connection between fatty acid oxidation which would actually be a better term for the phenomenon we are talking about is complicated and a decreasing respiratory exchange ratio, i.e. a reduction of the ratio of glucose to fat that's used to fuel your metabolism is not a reliable predictor of fat loss.

After the initial 45-minutes, during which the subjects' resting energy expenditure had been measured, the subjects were placed on a computer-integrated cycle ergometer on which they performed a standardized 30 minute sprint interval exercise (SIE) protocol., the scientists describe as follows:

"Sprint-Interval Exercise Protocol. The SIE protocol was performed on the Velotron DynaFit Pro cycle ergometer and comprised of four 30-second maximal effort intervals each separated by 5 minutes of low-intensity, constant workload cycling (Figure 2). First, the ergometer was properly adjusted for the subject. Adjustment specifications for each subject was recorded during their familiarization visit and repeated for all experimental trials. Subjects initiated the SIE protocol with a 5-minute interval of low-intensity cycling at a constant workload of 75W. Immediately after, subjects cycled with maximal effort for 30 seconds against an added resistance that is 7.5% of BW for males and 7.2% for females. These two intervals were repeated three additional times. After the last 30-second sprint interval, the subjects performed an additional low-intensity 75W interval plus an extra 3 minutes of cool-down at a constant workload of 30W. The total duration of the SIE protocol was 30 minutes" (Jo. 2015).

A workout that had little effect on the effect of the caffeine + green tea combo which did, as you can see, when you compare the "at rest" and "during SIE" values in Figure 1, increase the energy at rest and during sprint interval training to a similar extent. More specifically, the increase in energy expenditure and fat oxidation was - within the margin of inter-individual variability - in the range of +10% during both conditions.

Figure 2: Illustration of the sprint interval exercise test performed 55 min after ingesting the supplement (Jo. 2015).

In view of the fact that we may safely assume that this effect should last for at least 2-3h this can be a practically relevant effect if it is complemented by a reduced energy intake and a caloric deficit. If the latter is not present, even the extremest increases in fat oxidation and energy expenditure will fizzle out and be as irrelevant as the effect of the caffeine + green tea combination on exercise average and peak power (W) during the sprint training, Jo et al. observed in their study... and "Yes!", that is disappointing, but in view of the low dose of caffeine and the non-existent effects of green tea on performance during a test like this not really surprising.

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Bottom line: I admit, they certainly sound less exciting as the latest exotic herb from the rain-forest or a substance that is listed only under its funky chemical name on the label, but unlike your average "innovative breakthrough metabolic activator" caffeine and green tea will deliver. The 10% increase in metabolic rate and the accompanying increase in fat oxidation won't make you lose slabs of body fat, but the effects are pronounced enough to expect a measurable effect on the success of your next diet / cut. A cut, by the way, that will still require a significant reduction in energy intake, even if your energy expenditure and fat oxidation. So, don't be a fool and confuse a 10% increase in fat oxidation w/ a 10% increase in fat loss that occurs in the absence of dieting on an ad-libitum diet | Comment!

References:

• Jo et al. "Dietary Caffeine And Polyphenol Supplementation Enhances Overall Metabolic Rate And Lipid Oxidation At Rest And After A Bout Of Sprint Interval Exercise." Journal of Strength & Conditioning Research: Post Acceptance: November 23, 2015. doi: 10.1519/JSC.0000000000001277