Why Ray Recommends Eating Lots Of Calcium

[LeeLemonoil]

Amazoniac, your delving into both calcium and Vit D is awe inspiring and applepeeling.

Would you pls not mind my undercomplex and silly question to you please?

For someone like me who cannot tolerate dairy very well, even cheeses, which amount of which form of Ca would you suggest?

Also, do you think there Are any additional benefits to calcium pyruvate as a supplement ?

 

[Amazoniac]

Amazoniac, your delving into both calcium and Vit D is awe inspiring and applepeeling.

Would you pls not mind my undercomplex and silly question to you please?

For someone like me who cannot tolerate dairy very well, even cheeses, which amount of which form of Ca would you suggest?

Also, do you think there Are any additional benefits to calcium pyruvate as a supplement ?

It would be 200 mg 3x a day. The form is trickier.

Spoiler

- How Much Calcium Can You Absorb At A Time?

Such dosing is within the acceptable utilization range while remaining practical. It must also make up for what you'll miss by discontinuing dairy since the average contribution is half of the recommended intake and your consumption of industralized products (that may have been fortified) must be low. If the distribution throughout meals is even, each might provide something like 100-150 mg, and when combined with the supplemental 200 mg, it remains a reasonable quantity that won't lead to extreme rises in calcium that are off in relation to other nutrients that tend to exist together.

If their modeling in post #8 is accurate, there's something curious about it. Since efficiency improves as the dose is decreased, the total amount expected to be obtained when the dose is spread throughout the day should've been better and better the more you divide, but if you note, the rate is reduced. Once you start to get stuffed with sufficient amounts of calcium, utilization is decreased; the first doses are more important than the last ones. Therefore, if you experience detrimental effects, stick to low amounts and find means to conserve it while you figure out a way to make it work.

Not going crazy on sodium is one of them. Saving part of salting for when the meal is already prepared can prevent exaggeration, the tolerance is increased if it's added during preparation whereas sprinkling it on the surface of foods can accomplish the same effect without needing exorbitant amounts.

Some researchers have proposed that you lose 15 mg of calcium for every gram increment in sodium; if you only absorb 350 mg out of 1000 mg of calcium consumed in a day, 10 grams of sodium become concerning. But the body will enhance retention, so it takes multiple factors against it to be concerning.​

I always try to suggest less and people will be tempted to do more if they notice benefit, as opposed to beginning with a high dose, which makes people prone to quit in case of adversities and declare it a fail rather than decrease.


Regarding form, I would start with Raj's eggshells, initially plain for simplicity and to have a parameter. After a while, react them with a compound of choice to judge which one is better. Chances of exposure to contaminants present in calcium supplements should drop with this. Even though it's supposed to prevent their absorption, supplements that are used in large amounts could bring along unsettling amounts of them.

The other part of contaminants can be avoided if you opt to react the eggshells with food acids such as vinegar, citrus or perhaps apple juices rather than using industrial acids. I haven't looked if there's any apple variety that can contain enough free acids, but the reaction doesn't need to be complete. It can happen in the stomach, although doing it in advance is more guaranteed because you'll witness what's going on and it's one more step (going to ingest it anyway).

Since acidity is part of what preserves the juice, it's not wise to leave it standing for long, it's safer for the reaction to proceed in the refrigerator. I was once able to grow a colony on a solution of lime juice with eggshells that looked and smelled like cheese.

For reacting in the stomach, I would take a sip to down the supplement, wait for the burp and only then drink the beverage; this is to avoid indigestion. By the time you've burped, you'll know that it has been reacted. It's easier for the stomach acid to work when the volume is modest, contrary to diluting it in a ballooned stomach.

There are synthetic options such as butyric acid that can form therapeutic salts.

Some amino acids such as taurine and lysine improve its uptake and metabolism, which is one of the reasons why adding the supplement to protein-rich meals is recommended. They should go well together. Some people report dazedness from lysine supplements, I suspect that it can be mitigated this way.

In case you're prone to constipation, concentrate supplementation after your habitual pooping times and perhaps change pattern in a way that the greatest dose is taken with the last meal. Against expectation, it can be calming if your gut is overactive since it has a suppressive action (as mentioned by Raj). For some people it would be better to have it along with fermetable carbs to increase the acidity of the intestines and facilitate its uptake. Calcium can counteract this and neutralize short-chain fatty acids that might already be low.

If you're prone to diarrhea and the supplement doesn't help in normalizing transit time, I would pay attention if it isn't working like a 'hydrogen carbonate' sink and boosting elimination further.

Both cases probably do better when it's complexed with organic bases, they're gentler and less dependent on favorable conditions. But these may lower phosphorus more effectively than plain carbonate, and if you're already lacking it, it won't be any good.

Others will need the classic combination of magnesium, D, K2 and possibly boron.

Like I just mentioned elsewhere, there are proteins that hold the eggshell together and membrane residues that are potentially allergenic.
- Doubts About Eggshell Calcium?
If possible, compare the reaction with pure calcium carbonate to be sure that this isn't happening.

I'm not aware of any advantage to pyruvate over succinate or malate. For unusual forms, it's worth first finding out the fate of the molecule because this alone can defeat the intended purpose: some molecules are bound tightly and can be absorbed intact, others dissociate leaving calcium to be absorbed with chloride and the anion metabolized in the intestines, liver or everywhere.

 

[LeeLemonoil]

@Amazoniac

Thanks a lot for summarizing that, much appreciated!!

 

[Amazoniac]

- Could the beneficial effects of dietary calcium on obesity and diabetes control be mediated by changes in intestinal microbiota and integrity?

⬑ [47] The protective effect of supplemental calcium on colonic permeability depends on a calcium phosphate-induced increase in luminal buffering capacity

Spoiler

"An increased intestinal permeability is associated with several diseases. Previously, we have shown that dietary Ca decreases colonic permeability in rats. This might be explained by a calcium-phosphate-induced increase in luminal buffering capacity, which protects against an acidic pH due to microbial fermentation. Therefore, we investigated whether dietary phosphate is a co-player in the effect of Ca on permeability. Rats were fed a humanised low-Ca diet, or a similar diet supplemented with Ca and containing either high, medium or low phosphate concentrations."

"The diets had a high fat content to mimic the composition of a Western human diet. Dietary phosphate mainly originates from calcium phosphate and the protein source of the diet (casein: about 40 mmol phosphate/kg diet). The experimental diets were supplemented with

• 90 mmol CaHPO4.2H2O/kg diet (high-Ca, high-phosphate; HCaHP), or with
• 90 mmol CaCl2.2H2O/kg diet (high-Ca, medium-phosphate; HCaMP), at the expense of glucose.
• The high-Ca, low-phosphate diet (HCaLP) was supplemented with 90 mmol CaCl2.2H2O/kg diet, and the casein of this diet was replaced by whey protein isolate as a low-phosphate protein source (BiPRO, about 5 mmol phosphate/ kg diet; Davisco Foods International, Inc., Eden Prairie, MN, USA).

Thus, the experiment consisted of four different diets:

• LCaMP diet (reference diet; 30 mmol Ca and 70 mmol phosphate/kg diet),
• HCaHP diet (positive control since this diet has been used in our previous experiments, showing the effects of Ca on intestinal permeability (12,13); 120 mmol Ca and 160 mmol phosphate/kg diet),
• HCaMP diet (120 mmol Ca and 70 mmol phosphate/kg diet) and
• HCaLP diet (120 mmol Ca and 35 mmol phosphate/kg diet)."

"The Ca and phosphate content of the rat diets in the present study is nutritionally relevant for the human diet. In general, human dietary Ca intake in the Western world ranges from 600 to 1100mg daily (39). The Ca concentration of the low-Ca diet corresponds to a daily Ca intake of 600mg in humans, while the Ca-supplemented diets provided more than the general habitual dietary Ca intake (comparable to 2·4 g daily), which is not unrealistic when taking Ca supplements (12). In addition, the animal diets contained phosphate levels of approximately 160 mmol/kg diet (high-phosphate), 70 mmol/ kg diet (medium-phosphate) and 35 mmol/kg diet (lowphosphate), which are in the range of human intake of about 40 mmol phosphate daily (80 mmol/kg diet), assuming that humans have a daily dry food intake of about 500 g (39)."

"Buffering capacity was [] determined in the faeces of the pre-scFOS period. To this end, pools of the freeze-dried faeces (2 g) were reconstituted with double-distilled water to 15% dry weight."

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- Calcium: Taste, Intake, and Appetite

This review summarizes research on sensory and behavioral aspects of calcium homeostasis. These are fragmented fields, with essentially independent lines of research involving gustatory electrophysiology in amphibians, ethological studies in wild birds, nutritional studies in poultry, and experimental behavioral studies focused primarily on characterizing the specificity of the appetite in rats. Recently, investigators have begun to examine potential physiological mechanisms underlying calcium intake and appetite. These include changes in the taste perception of calcium, signals related to blood calcium concentrations, and actions of the primary hormones of calcium homeostasis: parathyroid hormone, calcitonin, and 1,25-dihydroxyvitamin D. Other influences on calcium intake include reproductive and adrenal hormones and learning. The possibility that a calcium appetite exists in humans is discussed. The broad range of observations documenting the existence of a behavioral limb of calcium homeostasis provides a strong foundation for future genetic and physiological analyses of this behavior.

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The other factors that affect skeletal wealth:
- Mechanical basis of bone strength: influence of bone material, bone structure and muscle action (check out references too, such as #172)
- Bone adaptation: safety factors and load predictability in shaping skeletal form (and #58, for example)

 

[Amazoniac]

For the monthly dose of killcium carbonate disappointment:

- Manganese Usage in Humans as Affected by Use of Calcium Supplements

"Calcium has long been implicated as a dietary factor which inhibits the absorption of manganese. Since manganese is better absorbed in the reduced (+2) than in the oxidized state (+3 or +4), any factor which increases gastrointestinal tract pH (increases alkalinity) would be expected to inhibit manganese utilization. Calcium carbonate, a commonly used antacid by humans as well as a calcium nutrient supplement, has been found to have a greater adverse effect on apparent manganese absorption in humans than does milk."

Spoiler

 

[Dave Clark]

For the monthly dose of killcium carbonate disappointment:

- Manganese Usage in Humans as Affected by Use of Calcium Supplements

"Calcium has long been implicated as a dietary factor which inhibits the absorption of manganese. Since manganese is better absorbed in the reduced (+2) than in the oxidized state (+3 or +4), any factor which increases gastrointestinal tract pH (increases alkalinity) would be expected to inhibit manganese utilization. Calcium carbonate, a commonly used antacid by humans as well as a calcium nutrient supplement, has been found to have a greater adverse effect on apparent manganese absorption in humans than does milk."

Spoiler

View attachment 19767

Take your calcium away from food and other supplements, i.e. bedtime.

 

[Tristan Loscha]

For the monthly dose of killcium carbonate disappointment:

- Manganese Usage in Humans as Affected by Use of Calcium Supplements

"Calcium has long been implicated as a dietary factor which inhibits the absorption of manganese. Since manganese is better absorbed in the reduced (+2) than in the oxidized state (+3 or +4), any factor which increases gastrointestinal tract pH (increases alkalinity) would be expected to inhibit manganese utilization. Calcium carbonate, a commonly used antacid by humans as well as a calcium nutrient supplement, has been found to have a greater adverse effect on apparent manganese absorption in humans than does milk."

Spoiler

View attachment 19767

Do you have an opinion on manganese uptake and requirements in obligate carnivores, and humans that try to mimic this lifestyle? Do you have an opinion on the manganese - parkinson's and parkinsonism angle, besides the known metal fume inhalation factor?

 

[Tristan Loscha]

Take your calcium away from food and other supplements, i.e. bedtime.

But then you get serum Calcium spikes, and these have undesired biological effects.

 

[Dave Clark]

But then you get serum Calcium spikes, and these have undesired biological effects.

Serum calcium is tightly regulated by the parathyroid gland. Taking calcium, magnesium, with some orange juice or collagen is not going to bind any manganese or cause a serum calcium problem. It should help provide restful sleep by keeping reactive stress hormones down by keeping parathyroid hormone levels down.

 

[R J]

- Calcium signalling in T cells
- TH17 cells thirsty for calcium
⬑ Calcium Signaling Controls Pathogenic Th17 Cell-Mediated Inflammation by Regulating Mitochondrial Function

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- Effect of Calcium Carbonate Particle Size on Calcium Absorption and Retention in Adolescent Girls
- Eggshell fractions containing different particle sized affect mineral absorption but not bone mineral retention in growing rats

That last study is saying medium eggshell size trumps both smaller and large in absorption! And the calcium carbonate study showed finer milled powder absorbed less than the larger! Surprising!

 

[Tristan Loscha]

Serum calcium is tightly regulated by the parathyroid gland. Taking calcium, magnesium, with some orange juice or collagen is not going to bind any manganese or cause a serum calcium problem. It should help provide restful sleep by keeping reactive stress hormones down by keeping parathyroid hormone levels down.

True, but high dose single intakes lead to short increases of serum calcium, PTH can not reactively suppress serum Calcium, only raise it; PTH is biased and geared to ensure higher serum availability if in doubt. The steadiness of calcium availability is very important, and Ca should be consumed with proper meals, or very low dose and steady with mineral rich water imo.

 

[Amazoniac]

Take your calcium away from food and other supplements, i.e. bedtime.

There are people who need to increase and others decrease the acidity of the intestine. For the former cases, the bolus dose at the end of the day as a desperate measure may work, an irresponsible amount could provide the person the daily requirement:

- How Much Calcium Can You Absorb At A Time?

Something like this:

But out of those salts, killcium carbonate is the form that depends the most on a meal for proper absorption. It would be preferable to choose a superior salt, stick to human doses or simply avoid it in meals that contain nutrients whose absorptions fare better in acidic medium.


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- Updates to Clostridium difficile Spore Germination

"Clostridium difficile, being an obligate anaerobe, is highly sensitive to oxygen, so the production of aerotolerant spores allows this organism to survive in the external environment until it infects a new host. In general, all bacterial spores are produced during a complex process known as sporulation, most often in response to nutrient deprivation ('starvation'). Spores are metabolically dormant and resistant to numerous environmental stresses, including oxygen, radiation, desiccation, ethanol, extremes of temperature, and low pH (11). Dormant spores can remain viable for hundreds of years (or longer) and return to a metabolically active state, a process known as germination, within minutes upon sensing specific nutrients that signal that the external environment may be favorable for growth (12)."

"When a patient ingests C. difficile spores, the spores are able to endure the acidic stomach and then transition to a metabolically active state (germinate) in the small intestine (29, 30). As C. difficile spores germinate, they lose resistance properties, outgrow in vegetative cells that produce toxins, and colonize the large intestine, where the vast majority of all pathologies occur (31–34). Therefore, germination is an essential step that occurs prior to outgrowth, colonization, toxin production, and the development of CDIs (35, 36)."

"Bacterial spore germination occurs within minutes in response to specific environmental cues, named germinants, that are believed to serve as indicators of conditions favorable for vegetative growth. Nutrient germinants are small molecules, such as sugars, amino acids, ions, and nucleotides, that induce the irreversible reactivation of spores into metabolically active bacilli via interaction with specific germination receptors (37, 38)."

"Unlike B. anthracis, which germinates when exposed to the nutrient germinants associated with phagocytes, C. difficile germinates in the gut in response to a combination of nutrients and bile salts present in the gastrointestinal tract, specifically, the bile salt cholate (55–60). Most derivatives of cholate can trigger spore germination; however, taurocholate (Tc) is the most effective germinant in vitro (61–63)."

"These bile salts are not sufficient for efficient C. difficile germination; a cogerminant, such as amino acids or divalent cations, is essential for the initiation of germination signaling (64–66)." "Glycine is the most efficient amino acid cogerminant for C. difficile spores, but it can also be replaced by other amino acids, such as L-alanine, L-histidine, and L-serine (64, 67–69)."

"In addition to the amino acid-dependent germination pathways, the divalent cations calcium and magnesium can also function as cogerminants in what we define as the bile salt-divalent cation pathway (Table 1) (66). This pathway does not require any amino acids or other typical nutrient germinants. Instead, sufficient levels of calcium (along with bile salts) circumvent the need for any amino acid cogerminants. Interestingly, there is synergy between the calcium and glycine pathways, where 10-fold-lower concentrations of each can induce efficient spore germination when provided in combination (66). This is likely the most physiologically relevant germination pathway, as bile salts, calcium, and glycine are all present in the host gastrointestinal tract. In fact, a recent study from our group suggests that calcium in the gastrointestinal tract can play a major role in inducing germination in vivo (66)."

[66] Intestinal calcium and bile salts facilitate germination of Clostridium difficile spores​

"The dependence of C. difficile germination on specific molecules, including bile salts, glycine, and calcium, has led to speculation that these molecules could be used to alter germination in vivo. In this context, many have focused on the idea of blocking germination in order to prevent outgrowth and the production of virulence factors. Indeed, if germination were completely inhibited, C. difficile spores would not convert to vegetative bacilli and, therefore, would not be produce toxins or cause disease. Since spores are inherently antibiotic resistant, this strategy could prevent disease in the short term, but since it does not specifically induce clearance of the spores from the body, it could increase the likelihood that the individual would experience a recurrence of CDI. Recurrence is a major problem in CDI, with 20 to 30% of individuals experiencing at least one bout of recurrent disease (99, 100). One recent study showed that this recurrence could be due to either reinfection of a susceptible individual or reactivation of latent spores within the individual's gastrointestinal tract (100). Knowledge of germination pathways and mechanisms could be exploited to activate spores within a host to prevent recurrence. If spores within the host are forced to germinate during antibiotic therapy, these would be killed by the antibiotic and unable to cause subsequent recurrence. Since bile salts are likely to be absorbed rapidly in the intestines, this strategy will likely require use of methods to target specific areas within the gastrointestinal tract. Increasing dietary calcium in individuals undergoing antibiotic therapy could have a similar effect, assuming the presence of sufficient levels of bile salt in the gut."​

Do you have an opinion on manganese uptake and requirements in obligate carnivores, and humans that try to mimic this lifestyle? Do you have an opinion on the manganese - parkinson's and parkinsonism angle, besides the known metal fume inhalation factor?

Probably lower requirement due to greater absorption (minimum interference, possibly not if the iron load is high) and ease of recycling (from discharged bile) until it gets to the inflammatory stage; it can be substituted by magnesium in some of its functions. I think that the issue of manganese toxicity was discussed in an unimportant thread.

That last study is saying medium eggshell size trumps both smaller and large in absorption! And the calcium carbonate study showed finer milled powder absorbed less than the larger! Surprising!

Thanks for mentioning it, from the last:

"Eggshell [ES] is a complex tissue composed of multiple layers which differ in the size and form of carbonate crystals (Hincke et al. 2012; Guru & Dash 2014). Eggshell layers also have protein matrix differences in interlacement and in chemical composition and solubility (Guru & Dash 2014). Thus, we suppose that the methodology used to obtain the eggshell fractions in the present study (milling and sieving) could differentially separate the components of eggshell layers generating particles [Small, Medium, Large] with similar Ca content but different Ca bioavailability. Supporting this proposal, we observed that the protein content was different among the eggshell fractions; the protein content of ES S was 28% higher than ES L fraction and 20% higher than ES M fraction. On one hand, the interlacement of proteins with Ca crystals could hamper Ca biological disintegration and dissolution in the ES S during digestion, and, consequently, its intestinal absorption. On the other hand, Ca absorption impairment in group ES L could be mainly explained by its greater size, which would delay its disintegration during the intestinal transit. In fact, we could observe eggshell particles in the crap of ES L group rats."​

 

[Tristan Loscha]

@Amazoniac
I see. Thanks for the info!

 

[Amazoniac]

- Gastrointestinal Absorption of Calcium from Milk and Calcium Salts

"Bo-Linn et al.[13] found that killcium absorption from killcium craponate was similar when intragastric pH was maintained at 7.4 and at 3.0, thus arguing against a crucial role of gastric acid in dissolving killcium salts. But there are other sources of acid in the gastrointestinal tract. These include food, acid secretions from the jejunum,[34] the acid microclimate adjacent to small intestinal cells,[35] and acid production by bacteria in the colon. Since the pH of a homogenized meal,[13] the proximal small-intestinal contents,[36] and the putative small-intestinal microclimate[35] is about 5, we tested the solubility of killcium salts at this pH."

"We found that even at a pH of 5.0, all the killcium salts except killcium virate were completely dissolved at one hour (it is not clear why killcium virate was not dissolved). Thus, it appears that even a mildly acidic pH is sufficient to solubilize most killcium salts completely in one hour."

Spoiler: Percentage of 500 mg of killcium dissolved in 500 ml of water at one hour, according to the pH of the water

- The Human Digestive Tract pH Range Diagram | Allegany Nutrition

"The pH of saliva is usually between 6.5-7.5. After we chew and swallow food it then enters the fundic or upper portion of the stomach which has a pH between 4.0-6.5. This is where 'predigestion' occurs while the lower portion of the stomach is secreting hydrochloric acid (HCI) and pepsin until it reaches a pH between 1.5-4.0. After the food mixes with these juices it then enters the duodenum (small intestine) where the pH changes to 7.0-8.5. This is where 90% of the absorption of nutrients is taken in by the body while the waste products are passed out through the colon (pH 4.0-7.0)."

Spoiler

'Several days' can be a sign of cascara sagrada deficiency.

 

[Amazoniac]

- The losses of calcium in cooking kale

"Since kale has been found to contain a good supply of calcium in a form which is easily assimilated by the human body, it was thought interesting to determine the amount of calcium which is lost during the cooking process."

"Peterson and Hoppert (34) state that the calcium loss in cabbage and spinach was 10% when they are steamed or pressure cooked and 20 to 30% when they are boiled. The greatest loss occurred in iron and the least in calcium. Certain vegetables showed notably large losses of calcium, particularly cabbage."

"Green vegetables are cooked with the cover off because part of the volatile acids will pass off with the steam and the development of the olive green color is less intense. The highest percent of these acids pass off during the first few minutes of cooking."

"Vegetables which start to cook in boiling water show less loss of minerals than those started in cold water."


"Since the calcium of kale had been shown to be nearly as well utilized as that of milk, this investigation was undertaken to determine how much calcium was lost in cooking kale by two common methods: boiling in a large amount and in a small amount of water."

"At first 100 gram samples were used, but as this seemed too large for an average serving, the amount was later decreased to 57 grams (2 oz.) per sample. This was the amount used in the final analysis of calcium."

"The variety of kale used for analysis was Brassica oleracea, var. acephal."

Spoiler

It must be easier to detect killcium in the liquid than in the food.
Not sure about the purity of water used in the experiment.

"[..]the average loss of calcium for the 15 minute period of cooking in one cup of water was 16%, while the average loss for the 20 minute period in two cups of water was 36%. Cooking in a large amount of water, then, at least doubled the loss of calcium in these experiments. The results might not be the same in cases where the kale was not grown under similar conditions and cut at the same time of the year."

"Peterson and Hoppert report the average loss of calcium for all the vegetables to be 20 to 30% when they are boiled for thirty minutes. The results of this investigation indicate that the losses of calcium in cooking kale by these methods are within the range reported by Peterson and Hoppert."


"Coons, Coons and Schiefelbusch state that the best retention of calcium in human pregnancy is found when the diet is base forming (13). Morgan and others, (33) found the greatest storage of calcium occurred on neutral or base forming diets. Their work was with dogs. Thus a diet which is acidic in the digestive tract and neutral or basic in the tissues seems to favor calcium retention."​

- Foods highest in Calcium in Vegetables and Vegetable Products

130 mg/100 g is much less than the content above. Cooking 300 g (that could contain 400 mg of killcium) and being able to extract 50% of the toxin would yield a solution that provides 200 mg of killcium. It's from 'The Shortening of Life: Pessimistic Studies'.

 

[Amazoniac]

- Is Citrate A Critical Signal in Immunity and Inflammation? (because of killcium virate)

When immune cells are activated, they undergo metabolic change in order to have sufficient energy to function effectively. The Krebs cycle is one of the most important pathways involved in this response and citrate, a critical component of this pathway, regulates carbohydrate and lipid metabolism. Recently, citrate has also emerged as a key immunometabolite, exerting specific effects on immunity and inflammation. Citrate has been shown to be involved in the production of prostaglandins and nitric oxide, and via the generation of malonyl-CoA and acetyl-CoA in the cytosol, to impact cytokine production. Citrate can also generate itaconate via aconitate, which promotes an anti-inflammatory response. All these findings support citrate as a crucial signal for immune cell activation and function.

In this review we will describe the various ways through which citrate participates in immune cell behaviour and speculate on the targeting of citrate as a possible novel therapeutic approach for immune and inflammatory diseases.

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Now Foods Calcium carbonate work for me. A very fine powder and does not cause gut irritating

Some people make art from garbage, we eat it. If you had a bad experience with the repurposed trash, do you mind detailing?

 

[Amazoniac]

- Molecular aspects of intestinal calcium absorption

"The total Ca2+ absorbed depends on the amount of Ca2+ consumed, the sojourn time in the various segments of the small and large intestine, and the amount of soluble Ca2+ available for absorption, which is mainly determined by the pH in each segment. The acidic environment of the stomach dissolves calcium salts into Ca2+ ions. However, the pH of stomach is less relevant than that of the other segments, as Ca2+ is absorbed in the small and large intestine. The average pH is 7.3 in the small intestine and 6.6 in the colon. When pH increases, Ca solubility decreases. Nevertheless, the duodenum seems to be the site with the maximum solubility of Ca, as the average pH is 6.0, which is the lowest in the entire gut[7]."

"Intestinal redox status is critical for both transcellular and paracellular pathways of intestinal Ca2+ absorption. Xiao et al[59] have demonstrated that a duodenal oxidation state induced by a high fat diet could significantly downregulate the expression of CB9k, PMCA1b, and NCX, as well as inhibiting intestinal calcium absorption. We have recently demonstrated that type I diabetes mellitus transiently inhibits intestinal Ca2+ absorption. Inhibition is accompanied by oxidative stress, which alters the gene and protein expression of molecules involved in the transcellular and paracellular pathways. When insulin is administered, the duodenal redox state returns to the control values, while intestinal Ca2+ absorption normalizes[60]. Similarly, oxidant drugs such as menadione, DL-buthionine-S,R-sulfoximine, and sodium deoxycholate decrease intestinal glutathione content, thereby affecting mainly the gene and protein expression of molecules involved in the transcellular pathway of intestinal Ca2+ absorption. Normalization of redox status with drugs such as quercetin, ursodeoxycholic acid, and melatonin returns intestinal Ca2+ transport to control values[61-65]."

"With regard to thyroid hormones, it has been reported that they produce a cooperative effect with vitamin D for intestinal Ca2+ transport. Apparently, thyroid hormones increase the genomic action of 1,25(OH)2D3 in the intestine[89]. Kumar et al[90] demonstrated that hyperthyroid rats show higher Ca2+ uptake and Ca2+ efflux from enterocytes than hypothyroid rats. They have also observed that NCX1 activity was highly increased by thyroid hormones, presumably via the cAMP-mediated pathway. Orihuela[91] has analyzed the effect of different statuses of thyroid hormones on the inhibitory effect of aluminum (Al) on intestinal Ca2+ absorption by using a rodent model. Mucosa-to-serosa Ca2+ fluxes in Al-exposed rats declined as thyroid hormones levels increased, thereby showing a trend opposite to that seen in non-Al-treated control rats."​

 

[Amazoniac]

Related to the previous post:
- Oxidative stress, antioxidants and intestinal calcium absorption
- Intestinal Ca2+ absorption revisited: A molecular and clinical approach

 

[SamYo123]

What if milk causes you to drop your temps in a non stressed state?


Metabolically damaging?

 

[Amazoniac]

- Evolution brings Ca2+ and ATP together to control life and death