Bitter Foods Increase Thyroid Function, Stomach Acid

lvysaur

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TAS2R bitter taste receptors regulate thyroid function
type 2 taste receptors (TAS2Rs), which are activated by bitter-tasting compounds such as those found in many foods and pharmaceuticals, negatively regulate thyroid-stimulating hormone (TSH)-dependent Ca2+increases and TSH-dependent iodide efflux in thyrocytes.

Caffeine induces gastric acid secretion via bitter taste signaling in gastric parietal cells
Caffeine induces gastric acid secretion via bitter taste signaling in gastric parietal cells
 
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lvysaur

lvysaur

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What about sugary coffee?

Well, coffee is a known inducer of stomach acid. I'm not sure if those studies were done with sugared/creamed or black coffee.

Sugar/creamed coffee still gives me a noticeable increase in stomach acid, so even if it diminishes the effect, it's still there.
 
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lvysaur

lvysaur

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Is it significant? two things comes to my mind: cacao and coffee :(

yeah, why would you imply it as a bad thing though? Plenty of people suffer from low stomach acid, which feeds bacteria and induces the hypo cascade.

If you have naturally high stomach acid (according to the blood type people, this is mostly type O but I'm skeptical), then just drink less coffee.
 

vulture

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I saw the study, but seems it requires a lot more work to find how relevant is it...I mean, let's suppose coffee and cacao decreases slightly Thyroid function, but also it lowers estrogen and prolactin effects importantly, maybe it's ok to pay that price...that's what I'm wondering
 
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lvysaur

lvysaur

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taste receptors ... which are activated by bitter-tasting compounds ... negatively regulate thyroid-stimulating hormone

High TSH is an indicator of hypothyroidism. It's not reducing thyroid hormone, it's reducing TSH.

This could be seen as increasing thyroid function, leading to a reduction in TSH.
 

vulture

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High TSH is an indicator of hypothyroidism. It's not reducing thyroid hormone, it's reducing TSH.

This could be seen as increasing thyroid function, leading to a reduction in TSH.
Sorry, misunderstood the whole thing up LOL
Moderator might be able to delete previous posts to keep the thread cleaner
 
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Well, coffee is a known inducer of stomach acid. I'm not sure if those studies were done with sugared/creamed or black coffee.

Sugar/creamed coffee still gives me a noticeable increase in stomach acid, so even if it diminishes the effect, it's still there.
How do you make creamed coffee?
 

Dave Clark

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I could be wrong, but I thought I had read that coffee and cacao are irritating to the stomach via caffiene, not by increasing stomach acid. Not everything that irritates the gut necessarily increases stomach acid (which can be a good thing if you are low in stomach acid and are trying to digest food, particularly protein)
 

Glassy

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Bitter herbs (eg dandelion, chicory) are supposed to be good for the liver (in herbal medicine). Filipinos eat a vegetable called bitter Mellon which litterally just taste bitter, primarily for health but you develop a taste for it and learn to enjoy it. I always wonder how humans ever got past the taste of something (bitter often means poison) and learn to eat something that is essentially unpalatable. Your liver converts T4 to T3 and a healthy liver is required for optimal thyroid function. I wonder if the increased stomach juices are a defence mechanism?
 

Lokzo

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Bitter herbs (eg dandelion, chicory) are supposed to be good for the liver (in herbal medicine). Filipinos eat a vegetable called bitter Mellon which litterally just taste bitter, primarily for health but you develop a taste for it and learn to enjoy it. I always wonder how humans ever got past the taste of something (bitter often means poison) and learn to eat something that is essentially unpalatable. Your liver converts T4 to T3 and a healthy liver is required for optimal thyroid function. I wonder if the increased stomach juices are a defence mechanism?
Great points there.
 

Travis

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@Travis, are you in the neighbourhood?
Yeah. It would be interesting to read this study to see how powerful the effect was since so many things go on at once in the body; the thyroid-stimulating effects of things bitter might not outweigh their negative effects, but since bitter things are often perceived so in such low concentrations it could be a thing to do. I remember taking wormwood tincture a long time ago since I had become a bit paranoid over some raw fish that I had, and I can say that merely one drop in glass of water is almost intolerably-bitter.
 

Amazoniac

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lvysaur said:

"Acid secretion in the stomach is a fundamental process that is finely regulated at different levels. Initial activation of GAS [gastric acid secretion] is regulated by the CNS when food is smelled and tasted (10, 35). When food enters the stomach, mechanical or chemical receptors (i) initiate GAS via activation of afferent/efferent fibers connected to the CNS, (ii) stimulate the gastrin-producing G cells or the histamine-producing enterochromaffin-like cells, or (iii) directly stimulate the HCl-producing parietal cells. Caffeine stimulates GAS, and, so far, it has been assumed that it acts via inhibition of PDE or by antagonizing adenosine receptors in gastric parietal cells (1). As caffeine activates five of the 25 human TAS2Rs (12), we hypothesized that its bitterness also contributes to its stimulating effect on GAS via activation of TAS2Rs."

"Real-time gastric pH measurements were performed after caffeine administration in human subjects by means of Heidelberg pH diagnostic capsules (29–32). Heidelberg pH capsules are used to determine gastric acid secretory ability under conditions simulating the ingestion of food or beverages by means of radiotelemetry. For the measurements, overnight-fasted subjects swallow the pH capsule, followed by a saturated sodium bicarbonate solution. Ingestion of the bicarbonate solution triggers an increase in stomach pH and a subsequent attempt by the parietal cells to reestablish acidity. The impact of foods or beverages on the reacidification time can be analyzed by administration of the test material before or after the pH challenge."

"Reacidification time was measured for three distinct delivery protocols (1–3), each of which assesses different sites of TAS2R activation []."

upload_2020-7-4_21-38-7.png

"First, we found that oral consumption of caffeine delayed GAS in healthy subjects, whereas caffeine that was administered encapsulated, being released in the stomach, accelerated this process compared with oral administration."

In order of appearance:
  • 125 ml water
  • 125 ml water + 150 mg caffeine: not tasted (encapsulated) and ingested
  • 125 ml water + 150 mg caffeine: tasted and ingested
  • 125 ml water + 150 mg caffeine: tasted but not ingested
upload_2020-7-4_21-38-20.png

"The delay induced by oral caffeine presentation might be explained by findings reported by McMullen et al. (36). They demonstrated that caffeine in a coffee drink accelerated the heart rate without increasing the vascular tonus in comparison with caffeine administered encapsulated concomitantly to a decaffeinated coffee drink. The increase in heart rate was likely induced by vagal withdrawal instead of sympathetic activation. This finding is important, considering that the cephalic-phase response during digestion is thought to activate the vagus nerve to enhance digestion (36)."

"The study of McMullen et al. (36) along with the present results suggest that orally sensed caffeine elicits vagal withdrawal that would reduce rather than enhance the digestive capacity, for example by delaying GAS. An explanation why the delaying effect of caffeine has not been discussed earlier might be that most of the previous studies investigating the effect of caffeine on GAS used gavages to bypass oral cavity receptors (2, 3, 5) and therefore did not take into account an inhibitory effect of caffeine on GAS by oral perception."

"Furthermore, we demonstrated that TAS2R bitter receptors in the stomach are involved in the caffeine-induced secretion of gastric acid. This conclusion is based on the observation that the bitter-masking compound HED similarly reduced caffeine’s bitterness as well its effects on GAS evoked by combined oral/gastric or gastric-only caffeine application."

"In this study, subjects swallowed a caffeine solution with or without a bitter-masking compound, homoeriodictyol (HED) (33, 34) 5 min after or 25 min before the bicarbonate challenge." "The intervention time of 25 min was chosen according to previous publications that demonstrated that caffeine starts to stimulate gastric acid after 30 min (2, 5)."

Given after alkalinization of the stomach:
  • 125 ml water
  • 125 ml water + 150 mg caffeine: tasted, mildened (HED) and ingested
  • 125 ml water + 150 mg caffeine: tasted and ingested
upload_2020-7-4_21-38-37.png

Given before alkalinization of the stomach:
  • 125 ml water + 150 mg caffeine: not tasted (encapsulated) and ingested
  • 125 ml water + 150 mg caffeine: not tasted (encapsulated), mildened (HED) and ingested
  • 125 ml water
"The intervention time of 25 min was chosen according to previous publications that demonstrated that caffeine starts to stimulate gastric acid after 30 min (2, 5)."

upload_2020-7-4_21-38-48.png

"The finding that concomitant oral ingestion of caffeine and HED accelerated passing of the Heidelberg capsule into the duodenum in 4 of 10 subjects compared with caffeine administration indicates that HED [masking bitterness] might induce gastric emptying. This hypothesis has been verified by measuring the effect of HED on gastric motility in strips of stomach dissections in an organ bath. Avau et al. (37) demonstrated that bitter compounds such as denatonium benzoate increased contractility in gastric strips of mice and caused an impairment of gastric relaxation after intragastric infusion."

"Based on our results, we hypothesize that bitter perception of caffeine in the mouth generates a signal of aversion, which leads, via vagal withdrawal, to inhibition of GAS (41). However, when bitter compounds reach the stomach, increased GAS could aid degradation or removal of the potential toxins. This hypothesis is supported by previous studies demonstrating that extraoral TAS2Rs are probably involved in defense mechanisms in other parts of the gastrointestinal tract and form a “chemofensor complex” (18, 19, 42). The differential effect of site-specific TAS2R activation on GAS we demonstrated has not been reported so far to our knowledge and warrants further investigations. The expression of TAS2Rs in murine goblet cells (18), a cell type that secretes mucus to protect the epithelium, and the fact that bitter substances increase anion transport and fluid secretion in human and rat colon tissue (42), indicate defense-related functions of bitter taste receptors."

"Furthermore, in intestinal cells, Jeon et al. (43) identified a TAS2R38-dependent activation of the ATP-binding cassette B1 (ABCB1) via phenylthiocarbamide (PTC). As ABCB1 is an efflux transporter located on the apical membrane of intestinal epithelial cells to limit absorption of toxic substrates contained in food, TAS2R signaling has been assumed to limit the absorption of potentially hazardous bitter-tasting substances in the intestine (43)."

"Our results clearly demonstrate that the route of application of caffeine determines its effects on GAS, and suggest that other bitter tastants and bitter-masking compounds are also potentially useful therapeutics to regulate gastric pH. Finally, our results support the pleiotropic functions of taste receptors far beyond their role in taste."
 
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