Category Archives: chocolate

Ketone bodies as signaling metabolites

*non sequiter*

One of the ways dietary carbohydrate contributes to liver fat is via ChREBP: “carbohydrate-response element binding protein.”  It responds to a glucose metabolite and activates transcription of lipogenic genes.  Insulin helps.  Ketones do the opposite (Nakagawa et al., 2013), by inhibiting the translocation of ChREBP into the nucleus where it does it’s dirty work:

 

ChREBP

 

More interestingly, ketones are histone deacetylase inhibitors (HDACi)… this leads to more histone acetylation.  Benefits of fasting sans fasting?  Modulating of acetylation is a MAJOR regulator of circadian rhythmicity.

Butyrate is another HDACi, so have some fibrous plant foods with your red wine and dark chocolate.  Anti-aging (mostly worm studies, but still).

 

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Because chocolate

To improve a memory, consider chocolate –NYT

Dark chocolate could improve memory by 25%, but you’d have to eat 7 bars a day –PBS

Dietary flavanols reverse age-related memory decline –Columbia University Medical Centre

dark chocolate

 

The actual study: Enhancing dentate gyrus function with dietary flavanols improves cognition in older adults (Brickman et al., 2014)

High flavanol group: 900 mg cocoa flavanols and 138 mg epicatechin (that’d be a LOT of dark chocolate).

Control: 10 mg cocoa flavanols and 2 mg epicatechin

Study duration: 3 months

Funding: NIH & Mars lol

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Paleo Plants and Carnivory

From what I gather, it’s been difficult to pinpoint the role of plants in the diet of our ancestors for a variety of reasons.  For example, evidence of plants on cooking tools and dental remains is suggestive but doesn’t disprove the possibility that said evidence came from preparing the plants for some other purpose (eg, tools, weapons, or medicine), or that the stomach contents of an herbivore was ingested (which gets partial credit).

That said, after reviewing a few studies on the topic (see below), it’s safe to say that plants were eaten, probably frequently, and the types & quantities varied seasonally & geographically.  Collectively, the data suggest we aren’t carnivores.

…you had to have something to hold you over until the next fish fell prey to your deadly hunting spear…  

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Lipid Hypothesis 2.0: Eat Butter

The original lipid hypothesis stated, more or less, that lowering blood cholesterol would reduce premature mortality from heart disease.  At the time, it was thought that dietary cholesterol and saturated fat increased the ‘bad’ type of blood cholesterol, so the advice was to restrict those foods.  All of that was wrong.

Time

Lipid Hypothesis 2.0: Eat Butter

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Animal fibre

Fruits and veggies, fermented or otherwise, aren’t the only source of prebiotics in your diet.  Eat a whole sardine and some of the ligaments, tendons, bones, and cartilage will surely escape digestion to reach the distal intestine where they will be fermented by the resident microbes.  

sardines

Salmon skin and the collagen in its flesh, the tendons that hold rib meat to the bone, and maybe even some of the ligaments between chicken bones.  All of these are potential prebiotics or “animal fibres.”  And it may explain why fermented sausages are such good vessels for probiotics.


 
“Animal prebiotic” may be a more appropriate term because the food matrix is quite different from that of non-digestible plant polysaccharides.  And while I doubt those following carnivorous diets are dining exclusively on steak, these studies suggest it might be particularly important to eat a variety of animal products (as well as greens, nuts, dark chocolate, fermented foods, etc.) in order to optimize gut health.

almonds

These studies are about the prebiotics in a cheetah’s diet.  Cheetah’s are carnivores, and as such, they dine on rabbits, not rabbit food.

cheetah

As somewhat of a proof of concept study, Depauw and colleagues tried fermenting a variety of relatively non-digestible animal parts with cheetah fecal microbes (2012).  Many of the substrates are things that are likely present in our diet (whether we know it or not).

Cartilage

Collagen (tendons, ligaments, skin, cartilage, bones, etc.)

Glucosamine-chondroitin (cartilage)

Glucosamine (chitin from shrimp exoskeleton? exo bars made with cricket flour?)

Rabbit bone, hair, and skin (Chicken McNuggets?)

Depauw ferments

The positive control, fructooligosaccharides (FOS), was clearly the most fermentable substrate; however, glucosamine and chondroitin weren’t too far behind.  Chicken cartilage and collagen were also well above the negative control (cellulose).  Rabbit skin, hair, and bone weren’t particularly good substrates.

As to fermentation products, collagen, glucosamine, and chondroitin were actually on par with FOS in terms of butyrate production:

Depauw SCFAs

Glycosaminoglycans (glucosamine and chondroitin) are found in cartilage and connective tissues (ligaments and tendons) and may have been mediating some of these effects as they’re some of the carbiest parts of animal products.  Duck Dodgers wrote about this in a guest post at FTA and in the comments of Norm Robillard’s article (probably elsewhere, too); very interesting stuff.

The authors also mentioned that the different fermentation rates in the first few hours suggests an adaptive component (some took a while to get going), or that certain substrates induced the proliferation of specific microbes.  “Animal prebiotics.”

Depauw close up

This is particularly noticeable for FOS (solid line), which is a plant fibre that wouldn’t really be present at high levels in a cheetah’s diet, so the microbes necessary to ferment it were probably not very abundant (initially).  Chicken cartilage (long dashes), on the other hand, started immediately rapidly fermenting, perhaps because this is more abundant in the cheetah’s diet.


 
Depauw took this a step further and fed cheetahs either exclusively beef or whole rabbit for a month (2013). Presumably, the beef had much less animal fibre than whole rabbit.  When they initially examined fecal short chain fatty acids, there were no major differences between the groups:

SCFAs per gram

However, if you take into consideration that the whole rabbit-fed cheetahs produced over 50% more crap than meat-fed cheetahs, then some other differences become apparent.  For example, the concentration of total SCFAs is actually greater in the feces from whole rabbit-fed cheetahs:

updated table

edit: la Frite pointed out that the table in the original manuscript is incorrect; the total SCFA numbers are reversed. The excel table above is corrected.

Further, the mere fact that there was 50% more fecal mass per day pretty much confirms way more animal fibre in whole rabbits.  And while neither of these studies were accompanied by microbial analysis, a more recent study on cheetahs fed primarily meat, “randomly interspersed with unsupplemented whole rabbits,” showed low levels of Bacteroidetes and Bifidobacteria, two potentially health-promoting groups of microbes (Becker et al., 2014).  I suspect this may have been at least partially due to a relative lack of animal fibre, compared to the Depauw’s exclusive whole rabbit diet.

Human digestive physiology and gut microbes are certainly far different from that of a cheetah, but maybe we too receive some prebiotic benefits from these animal fibres… just something to think about next time you’re eating sardines or pork ribs.

calories proper

 

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Fermented meat & probiotics

From Slate: “Sausage made with bacteria from baby poop isn’t as gross as it sounds.” 

and my favorite: “Pooperoni? Baby-poop bacteria help make healthy sausages.

Much ado about: Nutritionally enhanced fermented sausages as a vehicle for potential probiotic lactobacilli delivery (Rubio et al., 2014)

The media seems to have missed the ball, but not by far.  They focused on healthy microbes being incorporated into fermented meats, whereas the scientists seemed to want to make a “healthier” low-salt, low-fat sausage.

The low-salt part seems to partially make sense from a fermentation-perspective: using probiotics instead of salt to reduce the potential for pathogenic microbial contamination.  However, I doubt reducing the sodium by 25% will have any appreciable impact on health outcomes.  The effect of adding beneficial microbes, on the other hand, might.

They also mentioned making it lower in fat, but that doesn’t make as much sense; I don’t think there’s a big contamination risk of having a higher fat content.  #lipophobia

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Fish, dark chocolate, and red wine.

Fish oil fatty acids: EPA & DHA.

I’ve read that EPA tends to show slightly better results in outcomes related to mood, whereas DHA tends to be slightly better for cognition.  Not mutually exclusive; probably a lot of overlap.  This meta-analysis by Martins showed EPA fared better than DHA for depressive symptoms (2009); another one here, stressing the high %EPA relative to %DHA necessary for improvements (Sublette et al., 2011).  Whereas the reverse is true for certain cognitive outcomes in this study by Sinn and colleagues (2012).  Very few studies test EPA vs. DHA directly, and their effects on metabolism are relatively similar.  They’re the ball bearings of fatty acids.epa dpa dha

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Going Dutch on Dark Chocolate

During the production of dark chocolate, cacao beans are fermented, roasted, and processed into 3 components: chocolate liquorcocoa butter, and cocoa powder.  These are combined in various proportions to make unsweetened chocolate.  Sugar can be added to make dark chocolate, or milk & sugar added for milk chocolate.  White chocolate has no cocoa; it’s essentially cocoa butter, sugar, and milk.

ChocolateManufacturingChart

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Gut microbiome & short-chain fatty acids: resistant starch vs. prebiotics

Bifidobacteria undoubtedly like resistant starch (RS).  They bind and hold on tight, an effect mediated by cell surface proteins.  Big thanks to Tim Steele for passing along many of the studies cited here.  One of said studies showed that treatment of bifidobacteria with proteases abolished the RS binding; but even dead critters would bind if their cell surface proteins were intact (Crittenden et al., 2007).  

I suspect fermented foods have this all figured out.  The microbes in sauerkraut are going to be embedded in & all around the cabbage polysaccharides; likely protected from digestive enzymes (to a degree) and holding on tight.

Something similar has been shown for galactooligosaccharides (GOS) (Shoaf et al., 2006).  In this study, GOS, but not a variety of other fibres, inhibited the binding of pathogenic gut microbes to intestinal epithelial cells.

These mechanisms are likely not mutually exclusive, and both seem like they could benefit the host (us).

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Ketosis: anti-brain fog. Neurotransmitters, dietary protein, and the gut microbiome.

Treatment for dietary protein-induced brain fog: dark chocolate with 3% GOS and 10% MCTs.  Who’s in?

#IntermediaryMetabolism (bear with me here)
Ketosis from liver’s perspective:  increased fatty acid influx & [partial] oxidation causes acetyl-CoA levels to rise dramatically.  Concomitantly, gluconeogenesis redirects oxaloacetate (OAA) away from combining with acetyl-CoA via TCA cycle citrate synthesis and toward gluconeogenesis.  Since the acetyl-CoA doesn’t have much OAA with which to couple, it does itself to make acetoacetate.  Ergo, ketosis, and fortunately liver lacks ketolytic apparatus.

ketosis

 

Brain is singing a different tune.  Ketones provide ample acetyl-CoA and are efficiently metabolized in the TCA cycle.  Ketolysis is not ketogenesis in reverse, else liver would consume ketones.keto metabolism

Teleologically speaking (and I don’t really know what that word means), ketones are meant to spare glucose for the brain by replacing glucose as a fuel for peripheral tissues like skeletal muscle and displacing some brain glucose utilization.  The former is vital as one of the few sources of “new” glucose is skeletal muscle amino acids, and they would be exhausted in a short amount of time if skeletal muscle kept burning glucose –> incompatible with survival.  Getting some of that fuel from fatty acids, ie, ketones, is just way better.  Thus, the “glucose sparing effect of fat-derived fuel.”  And by “glucose,” I mean “muscle;” and by “fat-derived fuel,” I mean “ketones.”  There are numerous intracellular signaling events and biochemical pathways pwned, but that’s the gist of it.

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