How does calcium absorption work in the body. What factors can enhance or inhibit calcium absorption. Which dietary choices and lifestyle habits impact calcium uptake. How to optimize calcium intake for better bone health.

The Science of Calcium Absorption: Understanding the Basics

Calcium absorption is a critical process for maintaining strong bones and overall health. But how exactly does the body absorb calcium? The process begins in the stomach, where calcium dissolves in stomach acid. From there, it moves to the small intestine, where it’s absorbed through the intestinal lining and enters the bloodstream.

A common misconception is that different forms of calcium have vastly different absorption rates. In reality, most calcium supplements dissolve efficiently (95-100%) in stomach acid. The key difference lies not in dissolution, but in absorption and utilization by the body.

Absorption vs. Dissolution: Clearing Up the Confusion

Many people confuse calcium absorption with calcium dissolution. Dissolution occurs when stomach acid breaks down the calcium supplement. Absorption happens later, as the intestines take up the dissolved calcium and transport it into the bloodstream.

Contrary to some marketing claims, scientific studies consistently show that most calcium forms absorb at around 30%, give or take a few percentage points. This holds true for calcium carbonate, calcium citrate, calcium malate, and other common forms.

Factors That Enhance Calcium Absorption

While the type of calcium may not significantly impact absorption, several factors can influence how effectively your body utilizes this essential mineral:

• Adequate vitamin D levels
• Proper stomach acid production
• Calcium intake spread throughout the day
• Consumption of calcium-rich foods
• Regular weight-bearing exercise

The Crucial Role of Vitamin D

Vitamin D plays a pivotal role in calcium absorption. Without sufficient vitamin D, your body may struggle to absorb calcium effectively, regardless of how much you consume. Ensure adequate vitamin D through sun exposure, diet, or supplements as recommended by your healthcare provider.

Factors That Inhibit Calcium Absorption

Several dietary and lifestyle factors can interfere with calcium absorption:

1. High phytic acid intake
2. Excessive sodium consumption
3. Caffeine from coffee, tea, and sodas
4. Smoking
5. Certain medical conditions (e.g., celiac disease)

The Impact of Phytic Acid

Phytic acid, found in the bran coating of whole grains, can bind to calcium and other minerals, making them insoluble and difficult to absorb. If you consume a diet high in whole grains, consider balancing it with calcium-fortified products or adjusting your meal timing to optimize absorption.

Dietary Strategies for Enhancing Calcium Absorption

Optimizing your diet can significantly improve calcium absorption and utilization. Consider the following strategies:

• Pair calcium-rich foods with vitamin D sources
• Reduce sodium intake
• Moderate caffeine consumption
• Include calcium-fortified foods in your diet
• Balance whole grain intake with other calcium sources

Calcium-Rich Food Combinations

Combining calcium-rich foods with those high in vitamin D can enhance absorption. For example, try pairing dairy products with fatty fish or eggs. Alternatively, consider calcium-fortified orange juice with added vitamin D.

Lifestyle Factors Affecting Calcium Absorption

Beyond diet, several lifestyle factors can impact your body’s ability to absorb and utilize calcium:

• Physical activity level
• Smoking habits
• Alcohol consumption
• Stress levels
• Sleep quality

The Benefits of Weight-Bearing Exercise

Regular weight-bearing exercise not only stimulates bone formation but also enhances calcium absorption. Activities like walking, jogging, dancing, or resistance training can help improve your body’s calcium utilization.

Medical Conditions Impacting Calcium Absorption

Certain medical conditions can significantly affect calcium absorption and metabolism:

• Celiac disease
• Inflammatory bowel diseases
• Hyperparathyroidism
• Vitamin D deficiency
• Kidney disorders

Celiac Disease and Calcium Absorption

Celiac disease, an autoimmune condition characterized by gluten intolerance, can damage the intestinal lining and impair absorption of nutrients, including calcium and vitamin D. If you have celiac disease, work closely with your healthcare provider to manage your condition and optimize nutrient absorption.

Supplementation Strategies for Optimal Calcium Absorption

If you’re considering calcium supplements, keep these strategies in mind:

• Choose a supplement with added vitamin D
• Take smaller doses throughout the day
• Avoid taking iron supplements at the same time
• Consider calcium citrate if you have low stomach acid
• Consult your healthcare provider for personalized advice

Timing Your Calcium Intake

Taking smaller doses of calcium throughout the day can improve absorption. Your body can typically absorb about 500 mg of calcium at a time, so spreading your intake across meals and snacks may be beneficial.

Beyond Absorption: The Importance of Calcium Utilization

While absorption is crucial, it’s equally important to consider how your body utilizes calcium once it’s in the bloodstream. Factors that influence calcium utilization include:

• Hormonal balance
• Magnesium levels
• Vitamin K2 intake
• Overall nutritional status
• Bone remodeling rate

The Synergy of Calcium and Vitamin K2

Vitamin K2 plays a crucial role in directing calcium to the bones and teeth, where it’s needed most. Adequate vitamin K2 intake can help ensure that absorbed calcium is properly utilized for bone health rather than deposited in soft tissues.

Monitoring and Maintaining Optimal Calcium Levels

Ensuring proper calcium absorption and utilization requires ongoing attention. Consider these strategies for long-term calcium health:

• Regular bone density scans
• Periodic blood tests for calcium and vitamin D levels
• Consultation with a registered dietitian
• Adjusting calcium intake based on age and life stage
• Staying informed about the latest nutrition research

The Importance of Regular Check-ups

Regular medical check-ups can help you monitor your calcium levels and bone health. Bone density scans, in particular, can provide valuable information about your bone mass and help guide your calcium intake and overall bone health strategy.

Optimizing calcium absorption is a multifaceted process that goes beyond simply consuming calcium-rich foods or supplements. By understanding the factors that influence absorption and implementing targeted dietary and lifestyle strategies, you can significantly enhance your body’s ability to absorb and utilize this essential mineral. Remember, while calcium is crucial for bone health, it’s just one piece of the puzzle. A balanced diet, regular exercise, and overall healthy lifestyle habits all contribute to strong bones and optimal health.

As research in nutrition and bone health continues to evolve, stay informed and consult with healthcare professionals to tailor your calcium strategy to your individual needs. By taking a comprehensive approach to calcium absorption and utilization, you can support your bone health and overall well-being for years to come.

Key Factors for Absorbing Calcium Supplements

Calcium Soluability

If calcium is soluble, it dissolves easily in water or stomach acid. (In fact, it is not uncommon for calcium supplements to be close to 100 percent soluble.) Calcium dissolves in the stomach and is absorbed through the lining of the small intestine into the bloodstream. Once in the bloodstream, calcium builds bone, regulates the expansion and contraction of the blood vessels, and performs other important functions.

Key Factors

Here are key factors that can affect how well your body is able to absorb the calcium you take in.

• A diet high in phytic acid — Found in the bran coating of whole grains, phytic acid binds calcium and other minerals, making them insoluble and not absorbable in the intestines. Your calcium then passes out of the body without being absorbed. If you typically consume a lot of whole-grain bread and cereal, you may want to try calcium-fortified products.
• High levels of sodium — Excessive salt can interfere with calcium absorption. Read more about salt and the health of your bones.
• Insufficient vitamin D — Vitamin D is critical to regulating calcium absorption.
• Coffee (and tea) consumption — The caffeine in coffee, tea, as well as most sodas acts as a mild diuretic, so that valuable calcium is excreted before the body can make use of it. Consuming these drinks in small quantities is relatively harmless, but excessive use can lead to reduced absorption.
• Smoking — Studies of smokers show reduced bone mass. The reason is not well understood, but it appears that smoking interferes with the absorption of calcium in the intestines. PLEASE STOP SMOKING.
• Celiac Disease ­— This health condition is an inherited autoimmune disease characterized by gluten intolerance. It often goes undiagnosed in both children and adults. Celiac disease changes the lining of the intestine and impacts absorption of fat-soluble vitamins and minerals, such as vitamin D and calcium. If you have celiac disease, it is a significant risk factor for osteoporosis. 

Other Factors

Other factors, such as an inactive lifestyle and a diet that features a large amount of meat, may also affect your ability to absorb calcium. American Bone Health suggests that you discuss these factors with your healthcare provider and evaluate your own diet and lifestyle for areas where you can make improvements.

Posted: 9/28/2016; Revised: 03/04/20. 
As a service to our readers, American Bone Health provides access to our library of archived content. Please note the date of the last review on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician

Calcium Absorption – What Really Matters?

When it comes to calcium absorption, there’s a lot of contradictory information out there.

A quick internet search for “calcium supplements” will return a ton of results claiming one particular calcium is more absorbable than another. But anyone making these claims is either “marketing” their calcium, or falling prey to a common misconception…

Because the truth is, given the right circumstances, all types of calcium are absorbed very similarly. (We’ll go over what circumstances can affect absorption in a moment!)

Now, this may come as a bit of a shock because we’re so used to hearing about calcium in terms of absorption. But the problem is, when people talk about absorption, what they’re really talking about is “dissolution”.

Let’s have a look at the difference between the two!

Calcium Absorption vs. Calcium Dissolution

Some companies that claim their calcium is “better absorbed” are mistaking absorption for dissolution. Yet these are two very different mechanisms.

Dissolution is your stomach acid dissolving the calcium salt when first ingested.

Absorption is your intestines taking up the calcium after dissolution and sending it into your bloodstream.

Now, all calciums dissolve very well in stomach acid— 95-100% dissolution is normal. But the confusion occurs because people use this number in reference to absorption… which as we’ve seen, is a very different thing!

And when it comes to absorption, the science points in one direction. Studies show that all calcium salts absorb a few percentage points above or below 30%.

There’s no wild variation in absorption rates depending on your source of calcium. Calcium carbonate, calcium citrate, calcium malate… it doesn’t make a difference! There’s no calcium on earth that absorbs at 90% or at 5%. They ALL absorb at around 30%.

That said, just because all calcium types absorb around the same, it doesn’t mean they’re all made equal. As we’ll see in just a moment, it’s what happens after absorption that really matters.

But first, there are a few things that can affect calcium absorption.

What Factors Affect Calcium Absorption?

Although the source of calcium doesn’t affect absorption rates, there are a few factors that do! Here, we’ll review what to keep in mind to get the most out of your calcium supplements.

Take Your Calcium With Food

As we covered earlier, before you can absorb calcium, it needs to dissolve in your stomach. And to properly dissolve the calcium you consume, you need stomach acid! When you eat, you produce stomach acid which is why we recommend taking AlgaeCal with a meal or snack.

The one exception to the rule is calcium citrate. You don’t need stomach acid to dissolve this form of calcium which is why it’s recommended for people who’ve had gastric bypass surgery.

But remember, just because it dissolves easily, doesn’t mean it absorbs better! After dissolution, calcium citrate absorbs at the same rate as all other calciums.

Ensure You’re Getting Adequate Vitamin D

You may have heard that vitamin D is crucial for bone health, and here’s why: you need vitamin D to properly absorb calcium.

Without adequate vitamin D, your body can only absorb 10-15% of the calcium you consume. And this applies to all forms of calcium— whether it’s from food, calcium carbonate, calcium citrate, or any other kind of supplemental calcium.

Now, calcium is both actively and passively absorbed in the small intestine.

Active absorption is what scientists call “transcellular”. This means calcium passes directly through cells on its way to your bones.

Passive absorption, on the other hand, is “paracellular”. This means calcium takes a bit of a longer route and passes between cells.

But the amount of calcium you absorb passively is quite small compared to the amount you absorb actively! And you need vitamin D to actively absorb calcium. Which is why you can only get a fraction of the calcium you consume without it.

But what qualifies as “adequate” vitamin D? Well, studies show that an optimal blood level of vitamin D is around 250HD.

In one of these studies, researchers measured calcium absorption in two groups. The test group was pre-treated with vitamin D, while the control group was not. All participants received 500 mg oral calcium with breakfast, and blood was taken throughout the day to gauge calcium levels.

In the end, the group given vitamin D absorbed 65% more calcium than the control group! These results clearly demonstrate the importance of vitamin D for calcium absorption.

If you’re concerned about your vitamin D levels, it’s a good idea to get them checked with your doctor. Once you know where you stand, you’ll be able to make an informed decision on whether you need to supplement to maintain healthy vitamin D levels.

Take a Maximum of 500 mg of Calcium at a Time

Research shows that you absorb calcium most effectively in amounts of 500 mg or less. Amounts greater than 500 mg are poorly absorbed so it’s eliminated in your urine.

It’s worth noting that research also shows, for best results, you should take your calcium supplements in a dose of around 350 mg, twice daily.

To come to this conclusion, researchers looked at a sample of 37 men and women. They divided them into two groups: one group received 1000 mg of calcium all at once while the other group was given 300 mg.

Now, the subjects that received the 1000 mg were only able to absorb around 28.4% of the calcium from that dose. On the other hand, the group that received 300 mg, absorbed 36%. (Notice how these two values fall in the calcium absorption range of slightly above or below 30%!)

From these results, researchers determined that a dose of around 350 mg taken twice daily, may provide the best absorption of calcium. And that no more than 500 mg should be taken at a time. Think of it like this: you’re not overloading your small intestines with work that way.

Why Calcium Absorption Isn’t A Big Deal

It may seem intuitive that you’d want to absorb as much calcium as possible. And considering all the talk about “absorption”, it certainly seems that way! But this is another common misconception.

Here’s why:

Without excess calcium (calcium not absorbed into your bones) your body wouldn’t function properly. There’s a lot more to calcium than bone health. It plays a key role in vital biological processes outside your bones too.

So, excess calcium can actually be a great thing! According to the late Dr. Robert Heaney, arguably the world’s top calcium researcher, excess calcium can reduce prostate and colon cancer rate. It does this by combining with oxalates— an organic acid linked to many health problems including colon cancer. The calcium then carries these toxins out with your feces.

What’s more, calcium has been linked to positive health benefits like lower blood pressure and weight loss!

So, even if a hypothetical “95% absorbed” calcium supplement existed, you wouldn’t want to take it.

If you did, not only would the rest of your body miss out on calcium, but it would be calcium overload for your bones. Because just like not getting enough calcium can harm your bone health, getting too much can be harmful too.

Too much calcium can cause a nutrient imbalance. For example, it can trigger a magnesium deficiency. And without adequate magnesium, calcium can’t do its job properly… which defeats the purpose of taking calcium supplements in the first place.

So really, absorbing more calcium is beside the point. The focus should be on what a calcium supplement can do for your bone health, not on absorption. Which leads us to our next point: it’s what happens after absorption that really matters!

What Happens After Absorption Is What’s Really Important!

What you care about most is strong, healthy bones, right? So, what good does absorbing calcium do if you’re not building bone density?

This is why what happens after your body dissolves and absorbs your calcium supplement is the important part. Because after all this has taken place, you still need to make sure your body can use the calcium the way you want.

Now, we spoke earlier about how you need a bit of excess calcium in your body, but the main reason you’re taking a calcium supplement is to improve your bone health. So you want a large chunk of the calcium you consume to make its way to your bones.

This is where “helper” nutrients come into play. As we mentioned before, vitamin D is key for making sure you can absorb calcium in the first place. But there are a few more vitamins and minerals you’ll want to take note of as well.

Vitamin K, especially in its K2 form, is another vital ingredient for healthy bones. In fact, you could consume more than enough calcium, but without vitamin K2, you’d still have weak bones… because they wouldn’t receive any of that calcium!

Vitamin K2 activates two proteins that handle where calcium goes in your body. These two proteins direct calcium to your bones and keep calcium out of places you don’t want it (like your blood vessels and kidneys).

Magnesium is also essential for healthy bones— it keeps them strong and malleable with the help of other minerals like boron, copper, nickel, phosphorus, silicon, and zinc (all of which are found naturally in AlgaeCal!). But in terms of calcium, too little magnesium can affect absorption.

This is because magnesium impacts the amount of parathyroid hormones you produce. And parathyroid hormones regulate how much calcium your body absorbs.

The moral of the story is that calcium doesn’t work in isolation to strengthen your bones. You need a balance of many vitamins, minerals, and the right circumstances to increase your bone density. A fact that is made clear by calcium’s inability to build bone when taken by itself!

This is why AlgaeCal uses a multi-nutrient approach to bone health. AlgaeCal Plus contains all 13 essential bone-supporting minerals and clinical doses of magnesium and vitamins K2 and D3. The combination of these nutrients ensures that calcium is delivered to where you need it most: your bones.

What’s more, the strain of algae that AlgaeCal is sourced from, Algas Calcareas, actually contains all the bone-supporting minerals in the balance your body needs them— naturally! It uses these minerals to support its own structure, so they’re basically pre-approved to support your bones too.

And since AlgaeCal comes from a natural, plant-based source, it won’t cause any nasty side effects like stomach upset and constipation either!

Calcium Absorption Takeaways

At the end of the day, it’s not calcium absorption you should be worrying about. It’s increasing your bone density.

But because of marketing misinformation, “absorption” is chocked up to be more important than it is. Yes, you need to absorb calcium to build bone. But all calciums absorb the same, at around 30%!

Plus, even if a calcium supplement could offer 95% absorption, you wouldn’t want to take it…

Your body needs calcium that’s not absorbed for many other essential biological functions like fighting toxins and lowering your blood pressure. So, if you absorbed too much calcium, there wouldn’t be enough leftover for the rest of your body!

That said, there are some factors that can affect absorption like:

• Whether you take your calcium with food
• Your vitamin D levels
• How much calcium you take at one time

But once again, ensuring you absorb calcium well doesn’t mean much, if it isn’t doing anything for your bone health. Which is why you need other essential minerals and vitamins with your calcium.

Specifically, vitamin D and K2, and magnesium (to name a few). These three nutrients help your body both absorb and use calcium to the best of its ability— and to the benefit of your bones!

Without these “helper” nutrients, you could take calcium supplements for years, and at best, you’d slow your bone loss. But when all the nutrients and minerals your bones need work together, then you can actually build bone density.

That’s why AlgaeCal’s multi-nutrient, plant-based calcium supplement is guaranteed to increase your bone density in as little as six months!

Calcium. General information

In the human body, more than 98% of Ca is fixed in bone tissue, and only 1–2% is in soft tissues and extracellular fluid, incl. in blood. In blood serum, 40% Ca circulates in complex with proteins, 9% in the form of salts (phosphates, citrate), the remaining 50% are present in the ionized (free) form (Ca2+) and therefore are able to diffuse into the intercellular fluid. It is free calcium that is the regulator of intracellular processes.

Physiologically, the action of Ca is associated with the regulation of the permeability of cell membranes. In the cell, its concentration is very low; on the outer side of the plasma membrane, the Ca2+ content is many times higher. The establishment of such a balance of concentrations is ensured by the energy-dependent operation of membrane channels and pumps. Due to the low content of Ca2+ in the cytoplasm and the high concentration gradient on both sides of the plasma membrane, this ion is important in the regulation of cell activity. The plasma membrane of cells has a low permeability to calcium; the removal of the ion from the cell is energy dependent. Changes in the conductivity of calcium channels in the membrane and intracellular Ca2+ content change the functioning of many systems, including the processes of cell division. Calcium ions play an important role in the transmission of nerve impulses, muscle contractility, in the process of blood coagulation, and are cofactors in a number of enzymatic reactions. Determining the level of calcium is a diagnostically and prognostically significant test for a number of pathological conditions.

To maintain a normal level of calcium in the blood serum, it is necessary to adequately supply it with food. The intake of calcium in the body is affected by its content in food and their composition. The presence in the diet of substances that bind calcium, primarily phosphates and fatty acids, significantly reduces its absorption. Calcium absorption occurs predominantly in the proximal small intestine and in the jejunum. The intestines absorb from 30 to 70% of the calcium supplied with food.

Clinically, hypercalcemia manifests itself as a violation of the kidneys (polyuria, urolithiasis), gastrointestinal tract (nausea, vomiting, constipation), heart (shortening of the QT interval on the ECG), neurological symptoms (weakness, fatigue, confusion, stupor and coma). Clinical manifestations of hypercalcemia are more pronounced with its rapid development.

Clinical manifestations of hypocalcemia vary depending on the degree of calcium reduction. Muscle fatigue, weakness, twitching of individual muscle groups, positive symptoms of Khvostek, Trousseau, Lust are noted with a mild degree of hypocalcemia. Alkalosis increases the albumin-bound calcium fraction, exacerbating symptoms. Severe hypocalcemia causes drowsiness, confusion, spasms of smooth muscles, hypertonicity and convulsions, prolongation of the QT interval on the ECG. Chronic hypocalcemia can cause cataracts and calcification of the basal ganglia.

The exchange of calcium in the body is closely related to the exchange of phosphorus. The main factors regulating the metabolism of phosphates and calcium include PTH, calcitonin and vitamin D. When hypocalcemia occurs, an increase in PTH synthesis occurs, which provides increased tubular reabsorption and a decrease in calcium excretion in the urine. At the same time, under the influence of PTH, the excretion of phosphorus by the kidneys increases, which leads to a decrease in the concentration of phosphorus in the blood serum and extracellular fluid and a subsequent increase in the level of calcium in the blood. Hyperphosphatemia is accompanied by a decrease in calcium concentration, which leads to stimulation of the release of PTH, a decrease in tubular reabsorption of phosphate and an increase in its excretion by the kidneys.

The content of Ca in blood serum and urine changes with dysfunction of the parathyroid and thyroid glands, neoplasms of different localization, especially with bone metastasis, and renal failure. Prolonged hypercalcemia in combination with both hyper- and normophosphatemia can cause calcium phosphate deposition in the wall of blood vessels, connective tissue, gastric mucosa, and other organs and tissues.

Calcium metabolism in birds « Stella Veterinary Clinic. Veterinary services for cats and dogs. Calling a veterinarian at home in Moscow.

1 part. Metabolism of calcium, phosphorus and vitamin D3 in birds.

1.5% of a bird’s body weight is calcium, which is one of the most abundant minerals in the body, found primarily in the skeletal system.

Physiological functions:

Calcium is involved in the process of blood clotting, is involved in the transmission of nerve impulses, the permeability and excitability of cell membranes, the activation of enzymatic systems, the secretion of glands, muscles, calcification of the eggshell and contraction of the uterus during egg laying. A low level of calcium in the blood as a result of increased excitability, due to a decrease in electrical resistance, leads to an increase in the permeability of sodium and potassium into the membrane of nerve tissues.

Normal blood calcium level is in the range of 2.0-2.8 mmol/l. Calcium levels vary considerably between species.

Budgerigar range 1.6 – 2.54 mmol/L
African Gray Parrot 2.10 – 2.59mmol/L,
Amazon 1.87 – 2.42mmol/L,
Macaw 1.70 – 2.47 mmol/L,
for cockatoo 2.2-2.7 mg/dL, and
for canary 1.27 – 3.34 mmol/L.2

However, when considering the normal range of calcium in the blood, we often take as the normal range those values ​​that we get from birds living in captivity and receiving a poor grain diet. Wild birds in nature have completely different blood counts. Moreover, these ranges do not take into account the normal physiological processes that occur immediately before and during egg laying, as well as other naturally occurring fluctuations.

There are three different forms of calcium in the blood:

– ionized calcium, which is a physiologically active form.
– total calcium associated with proteins (mainly albumin)
– chelated calcium (residual), associated with phosphates or citrates.

Total blood calcium should be interpreted together with plasma proteins (especially albumin). blood calcium.Glucocorticoid therapy reduces total calcium concentration by increasing urinary excretion and decreasing intestinal absorption of calcium.In addition, an increase in calcium concentration has been reported with an excess of vitamin D3 in the diet, osteolytic bone tumor and dehydration.

Calcium is absorbed in the upper small intestine. Calcium enters the mucosa (inner wall of the intestine) by a diffusion process and is then secreted into the blood by an active transport system involving calcium-binding protein. This system is regulated by the active metabolite of vitamin D3 (in response to low plasma calcium levels). There is also some absorption in the lower small intestine due to passive diffusion. Absorption is increased with a high protein diet and intestinal acidification, while components such as phytates (in cereals), oxalates (in spinach, rhubarb) and phosphates (meat) reduce calcium absorption due to the formation of complexes. Insoluble calcium salts are formed in the presence of high concentrations of free fatty acids (often found at very high fat content, eg sunflower or peanut butter). In addition, calcium circulates through the kidneys. Over 98% of the initially excreted calcium is reabsorbed back into the bloodstream from the urine.

Calcium metabolism is predominantly regulated by two hormones and one vitamin, which interact closely with each other if there are changes in the level of calcium in the blood. Paired parathyroid glands (one or two pairs depending on the type of bird) secrete parathyroid hormone in response to a decrease in blood calcium levels. The level of parathyroid hormone in the blood is usually extremely low. However, its level rises during the process of shell calcification. Parathyroid hormone initiates an increase in tubular reabsorption in the kidneys, which leads to a decrease in calcium excretion, and at the same time, vitamin D3 reabsorbs calcium from bone tissue and also increases calcium absorption in the intestine. So the level of calcium in the blood is increased, the level of parathyroid hormone and vitamin D3 increases.

Not only does parathyroid hormone increase the level of calcium in the blood, but it also affects the excretion of phosphate by the kidneys into the blood, thereby reducing the level of phosphate. This is important, since the exchange of calcium in the body, phosphorus and vitamin D3 are all inextricably linked. Although you can refer to a bird that it has a calcium deficiency, in reality it is an imbalance of Ca:P:D3.

The medullary bones (the middle part of the tubular bones) form a reserve of calcium to meet the calcium requirements during the laying period. During the laying cycle, parathyroid hormone controls the reabsorption of calcium from the medullary bone to meet the increased calcium requirement for eggshell production. It is also believed that estrogen levels, which rise before oviposition, cause a decrease in calcium in the blood, which also triggers the production of dihydrocholesterol. An increase in the level of parathyroid hormone leads to an increase in the level of calcium in the blood in less than ten minutes.

Vitamin D3 is converted to its active form 1.25 dihydrocholecalciferol in three steps that occur in the skin upon exposure to sunlight or ultraviolet light. In addition to increasing blood calcium and decreasing blood phosphorus levels, the main function of vitamin D3 is to increase intestinal absorption of calcium and phosphorus. This process takes effect after puberty and during the laying of the eggshell. This is an estrogen dependent process.

Calcitonin is a hormone produced by the thyroid gland. An increase in blood calcium levels increases the secretion of calcitonin, which in turn reduces the reabsorption of calcium from bone.

As mentioned above, at the center of calcium metabolism lies the so-called calcium to phosphorus ratio, which is based on the amount of phosphorus available to the bird as opposed to the total phosphorus content of the diet. During bone growth, most bird species require ratios of approximately 1.5:1 to 2:1 in order to maintain normal levels of calcium in the body. A 2:1 ratio is required to achieve maximum bone density. For reproductively active birds, a diet with a calcium to phosphorus ratio between 1:1 and 2:1 should be offered to prevent excessive mobilization of calcium from the bones. About 1% calcium in the diet in terms of dry matter content is sufficient for reproduction. Indeed, if there is more than 1% calcium, the eggshell may be too thick. According to various reports, the maximum allowable ratio varies from 0.5:1 and 2.5:1 to 0.8:1 and 3.0:1, ratios of more than 3.3:1 lead to rickets and limb deformities.

2nd part. Calcium content in feed or why Jaco can not seeds.

Most commercially available feed ingredients are extremely poor in calcium and contain a completely unacceptable ratio of calcium and phosphorus:
Sweet corn = 1:32
Pumpkin = 1:27
meat 1:20
Milo 1:14
Oats 1 :8
Safflower 1:8
Peanut 1:7
Sunflower seed 1:6
Millet 1:6
Pine nuts 1:4

Birds fed an unbalanced diet tend to suffer from malnutrition leading to illnesses such as respiratory infections or central nervous system disorders (convulsions, seizures or weakness).

As mentioned above, feeds consisting mainly of seeds and nuts are poor in calcium. Many parrot owners, when asked what their bird eats, exclaim: “Premium food.” Such foods include sunflower seeds, chili peppers, and dried fruit. But when asked by the same owner what the bird actually eats, the answer is: “only sunflower seed.”

Calcium content of some seeds:
Sweet corn 0.2 mg/dl dm
Millet 0.1 mg/dl dm
Oatmeal-0.8 mg/dl dm
Peanut 0.6 mg /dl dm
Pumpkin/Squash 0.5mg/dl dm
Safflower 0.8mg/dl dm
Sunflower Seed 1.2mg/dl dm
Wheat 0.6mg/dl dm

Fruit and most vegetables are also low in calcium. Most seeds are high in fat and low in vitamins A, D3, E, B12 and K1, B vitamins (riboflavin, pantothenic acid, niacin, biotin, choline), minerals and trace elements (iodine, iron, copper, manganese, selenium, sodium, calcium, zinc) and some essential amino acids.

Studies on the composition of seeds and seeds without shell show that the calcium content is halved when the shell is removed. As mentioned above, the high fat content of seeds such as sunflower and safflower can interfere with calcium absorption from the gut. There is a difference between sand and crushed shells. The sand is made up of tiny stones and usually contains silicates and sandstone. Crushed shells are composed almost entirely of limestone (calcium carbonate) and are easily digestible. Therefore, crushed shells serve as a source of calcium, while sand creates the main effect by mechanical grinding of food plant materials.

3 part. Diseases associated with impaired phosphorus-calcium metabolism.

During the reproductive cycle, there are physiological phenomena that are associated with changes in calcium metabolism.

A few days before ovulation, blood calcium levels may increase to 7.5mmol/L (estrogen-induced hypercalcemia). This increase in blood calcium, with deposition in the femur and humerus, will occur even when the bird receives little calcium from the diet. The concentration of ionized calcium (active calcium) remains constant. Reproductively active parrots prefer foods rich in calcium. Their calcium intake increases daily, during the pre- and early egg-laying stages. In addition, renal excretion of calcium decreases during shell formation. The synthesis of vitamin D3 in the kidneys and liver is stimulated by estrogens, prolactin and parathyroid hormones.

Bones become fully mineralized when both vitamin D3 and sex steroids are present in the blood. The skeleton can increase in weight up to 25% during the reproductive period. These bone changes are easily seen on radiography at this stage of the reproductive cycle. Nearly 10% or more of total body calcium is needed to cover the shell of each egg. Approximately 30-40% of eggshell calcium is derived from medullary bone if the dietary calcium concentration is below 2%. Conversely, if the calcium concentration is 3.6%, then the calcium for egg laying can be provided from the intestine rather than by reabsorption from the medullary bone. The eggshell is formed by reabsorption of calcium from the intestine, and its content in it gradually decreases, then the medullary bone becomes the source of calcium. In a bird that receives poor nutrition, over time the skeleton will become unusable, or the egg shell will not be sufficiently formed, or non-viable chicks will hatch.

In contrast to the physiological phenomena described above, there are several pathological conditions that affect hypercalcemia (excess calcium in the blood) or hypocalcemia (lack of calcium in the blood).

In female and male budgerigars, a pathological phenomenon can occur that resembles ossification of the bone marrow (polyostotic hyperostosis), but involves the humerus and femur, while normally it is predominantly ossification of the femur and lower leg. Parrots may show lethargy, thirst and frequent urination, bloating, weakness, paresis or paralysis of one or both legs. In some studies, this phenomenon is considered in association with an ovarian or testicular tumor, which supports the theory that this may be caused by increased levels of estrogens or testosterone and are produced by tumors of the gonads. Impaired liver function (often associated with a high fat diet, such as sunflower, peanut or millet, causing fatty liver) has been suggested as a possible cause, as the liver is responsible for removing estrogen from the blood.

Many of the problems that occur when hatching chicks, relate to calcium imbalance. Female birds lacking vitamin D3 or calcium may lay eggs with thin shells that are prone to cracking during incubation. If the embryo does not receive enough vitamin D3, there is a high risk of death. Underfeeding during the neonatal rearing period is a risk. While many adult birds cope with extremely poor nutrition, the chick will suffer from it. Orthopedic problems such as deformity of the limbs are most commonly caused by nutrient deficiencies during rearing (especially vitamin D3 and calcium). Indeed, these are the problems that we most often have in practice.

Secondary hyperparathyroidism results from inadequate calcium intake. This is the main problem of birds. This condition develops with limited absorption of calcium from food, which leads to an increase in the level of parathyroid hormones. High levels of phosphorus or low levels of vitamin D3 in the diet exacerbate the condition (as mentioned earlier, the Ca:P:D3 ratio plays a role here, which is a more important factor than calcium alone).

Clinical signs include hypocalcemia (low calcium in the blood), often causing convulsions, weakness, muscle spasms, increased thirst, loss of appetite, nausea, decreased egg production, soft egg production, egg binding, and brittle bones leading to pathological fractures.

Secondary hyperparathyroidism may also occur due to kidney disease. In severe chronic kidney disease, the conversion of vitamin D3 to the active metabolite is limited. As a result, calcium absorption in the intestine is reduced. In this condition, therapy is carried out with the use of calcium and vitamin D3 in the form of injections, and in the form of feed additives. In addition, birds should be put on a more balanced diet.

Metabolic bone disease occurs in birds in two forms: rickets, which may occur in growing birds, while osteomalacia (osteodystrophy) occurs in adult birds. Rickets is characterized by insufficient dietary intake of calcium, phosphorus and vitamin D3 or an inadequate ratio of calcium and phosphorus, which leads to enlargement of the parathyroid glands and secondary hyperparathyroidism. The result is that bones that grow by expanding long bones before cartilage is mineralized do not mineralize. Tubular bones bend under the pressure of weight. Bone deformities develop throughout the skeleton, especially in the distal tibia, femoral head, and ribs. Such chicks are often found in a characteristic position – sitting with a limb outstretched. Skeletal bones and beak become soft and supple. Deformed ribs can lead to difficulty breathing. Birds with osteomalacia and secondary hyperparathyroidism have an increased risk of fractures, medullary bone demineralization, and cortical bone demineralization. Spontaneous pathological fractures occur, according to the type of “green branch”. Most often, this affects the bones of the ribs, vertebrae, lower leg and tibia-metatarsus, and thighs.

4 part. Hypocalcemia of African gray parrots or why the gray parrot falls from the perch.

A gray parrot (Jaco) between the ages of two and five years has a so-called hypocalcemia syndrome. Clinical signs: incoordination. Jacos fall from the perch – this is often interpreted as weakness, convulsions and seizures. Indeed, hypocalcemia is a major cause of central nervous system disease. The bird suffers from hypersensitivity to noise or irritation. Notably, African gray parrots do not have skeletal demineralization to maintain normal blood calcium levels. Postmortem, the parathyroid glands of affected parrots appear normal, in other words, these glands make less effort to maintain normal blood calcium levels. Treatment of this disease consists of parenteral administration of calcium gluconate or calcium borogluconate, vitamin D3, and dietary supplements. Affected birds usually respond positively within minutes of starting treatment. Some doctors have admitted that a viral infection can affect the parathyroid glands, and the use of chlorine or oxytetracycline (an antibiotic) can lead to the development of a clinical picture of the disease. Studies have shown that African gray parrots have significantly less calcium, albumin, and total protein compared to Amazon parrots. This explains why exactly the Grays suffer from hypocalcemia. Symptoms are observed at serum calcium levels below 1.5 mmol/L and even 0.6 mmo/L. There are theories that these birds are not able to mobilize calcium from the depot. Parathyroid hormone deficiency has been suggested as the main cause of low blood calcium levels. Vitamin A deficiency may also play a role by inhibiting resorption activity and therefore hindering the mobilization of calcium from the bones. The same causes have been described in Amazons and red-tailed parrots.

Red-tailed hemorrhagic syndrome has been described in blue-fronted red-tailed parrots, yellow-winged red-tailed parakeets, and Patagonian parakeets. A viral etiology (retrovirus) has been suggested but has not yet been proven. Calcium deficiencies, together with a dietary lack of vitamin K and other nutrients, are thought to cause disease by possibly altering normal blood clotting mechanisms. There is bleeding from the nostrils, difficulty breathing, weakness, polyuria and diarrhea, and sometimes ataxia. In a biochemical study of blood, a decrease in total protein and calcium deficiency are noted. The development of pseudocysts in the pectoral muscles and pericardium was noted. All therapeutic regimens (injected vitamin K, vitamin D3, calcium, and antibiotics) failed. But sometimes calcium administration can prolong the bird’s life and can stabilize the patient.

Hypervitaminosis D3 (at more than 4-10 million IU/kg in the diet or at 3% calcium) causes abnormal calcification of the kidneys, vessels and arteries, as well as calcium deposition around the internal organs, affecting mainly to the liver, glandular stomach, intestines, heart and blood vessels. It is possible that with excessive levels of calcium in the blood, gout of the kidneys, visceral gout and a decrease in food intake can develop. Australian parrots appear to be most sensitive to high calcium or high calcium and vitamin D3 diets. Young Macaws are also more susceptible to hypervitaminosis D3.

Vitamin D3 deficiency symptoms are similar to those of calcium deficiency. This is not surprising, because in each case one of the metabolic links is disturbed. Adult females may lay eggs with thin shells or soft-bodied eggs, egg production and hatchability are reduced. Pathological fractures of the bones may be observed. In newborn chicks, fractures and deformed bones are especially common. A low calcium diet, especially if it is a diet high in phosphorus (found in meat, legumes, Brazil nuts and peanuts, pumpkin seeds, safflower, sunflower) will precede the development of clinical signs associated with hypocalcemia and hypovitaminosis D3. Hypovitaminosis D3 can develop due to low levels of D3 in the diet, malabsorption due to failure of synthesis in the liver or kidneys, or insufficient exposure to ultraviolet light. UV light provides the full spectrum of illumination required by birds. Once the light has passed through the window, the UV light will be removed. Obviously, parrots (including African Greys) were created to live in the natural environment, and not indoors from the sun.

Gout is the deposition of uric acid crystals in the organs (visceral gout), in the joints (articular gout) or in the ureters (renal gout). High intake of protein, calcium, hypervitaminosis D3, dehydration, cold and other stressors work together to prevent the kidneys from adequately removing uric acid from the body. In birds with kidney failure or gout, the intake of calcium, phosphorus, magnesium, sodium and vitamin D3 should be reduced to avoid mineralization of the kidneys.

Mineral deficiencies such as calcium, zinc, selenium, manganese and magnesium cause brittle feathers and itchy skin. There may also be changes in the color of the feathers. The plumage grows inhomogeneously, with a lack of sheen. There is also a symmetrical loss of feathers and impaired molting.

Rapidly growing waterfowl have rotation of the distal wing tip (outside the wrist) due to heavy, blood-filled flight feathers supported by brittle, poorly mineralized bones. The result is that the primary flight feathers stick out when the wing is folded at rest (giving rise to the colloquial term, wing angle or aircraft wing). The reasons are multifactorial. These include genetic disorders or malnutrition during incubation, rapid growth due to excessive protein and low calcium levels, calcium and phosphorus imbalances, and hypovitaminosis D3. This phenomenon has been described in budgerigars, macaws and red-tailed parrots.

Perosis: Primary or secondary manganese deficiency caused by excess calcium (which can bind manganese) and choline deficiency in the diet are thought to be responsible for the disease called “perosis”. Affected birds show thickening of the hocks along with deformity of the kink of the tibia and tarsal joint resulting from luxation of the Achilles tendon and rotation of the tarsus. This condition is seen in chicks, waterfowl, and ostriches, but there are no reports of perosis in parrots.

5 part. Conclusions on calcium metabolism.

If possible, allow the parrot access to unlimited daylight (at least a minimum of 45 minutes each day), or provide UV light with a full spectrum of lamps. Lamps should be kept 0.5 meters away from the bird, kept clean and replaced every 6 months.

The correct ratio of calcium and phosphorus in the diet (between 1.5:1 and 2:1) is essential. Foods high in phosphorus should be kept to a minimum (ie meat, legumes, brazil nuts and peanuts, pumpkin seeds, safflower, sunflower). Foods with the right Ca:P ratio should be encouraged (blackcurrant, citrus). Although there is some controversy about feeding chicken bones to parrots, it is beneficial in terms of calcium metabolism. You can give one bone per month, but the meat must be completely removed. It is necessary to ensure that the parrot is not injured by the sharp edges of the bones. If other sources of calcium are available, no pits are needed. If the parrot is not provided with a high quality granular diet, then it is certain that you will need to provide supplemental vitamin D3, calcium in a biologically active form.

Providing adequate levels of Vitamin A is important not only for calcium metabolism, but also for the prevention of respiratory infections. Vitamin A is found in large quantities in the following foods (as the concentration decreases: apricot, tomato, peach, pumpkin, plum, carrot, red pepper, corn, citrus, bell pepper). Food supplements are recommended, but should not be overfed (more than 1 month), otherwise it will lead to hypervitaminosis.

A few years ago, a study was conducted that showed that 75% of all sick parrots suffered from nutritional deficiencies, but since then, unfortunately, little has changed. The diet of parrots should be varied and balanced. This can be achieved by feeding some seeds along with germinated sprouts and fresh fruits and vegetables.