How does vitamin D impact calcium absorption. What role does the parathyroid hormone play in calcium metabolism. Which dietary components can interfere with calcium uptake. How can lifestyle factors affect calcium utilization in the body.

The Crucial Role of Calcium in Human Health

Calcium is an essential mineral that plays a vital role in numerous bodily functions. It’s not only crucial for building and maintaining strong bones and teeth but also involved in muscle function, nerve signaling, and blood clotting. However, the body’s ability to absorb calcium efficiently can be influenced by various factors.

Key Factors Enhancing Calcium Absorption

Several elements can positively impact the body’s ability to absorb and utilize calcium:

Vitamin D: The Calcium Absorption Enhancer

Vitamin D is perhaps the most critical factor in calcium absorption. It functions in the digestive tract to facilitate calcium uptake into the bloodstream through the walls of the duodenum. Additionally, vitamin D helps maintain normal blood calcium levels, ensuring that this vital mineral is available when needed.

Parathyroid Hormone: The Calcium Regulator

The parathyroid hormone (PTH) plays a significant role in calcium metabolism. It increases calcium transport across the membrane of intestinal cells, effectively boosting absorption. PTH also helps regulate calcium levels in the blood by stimulating bone resorption when necessary.

Acidic Environment: The Calcium Solubility Enhancer

An acidic environment in the stomach is crucial for optimal calcium absorption. Hydrochloric acid, secreted during digestion, helps create the ideal conditions for calcium to become soluble and ready for absorption in the small intestine.

• Calcium supplements are often recommended to be taken with meals to take advantage of the natural increase in stomach acid production.
• Some people may benefit from taking calcium supplements with magnesium at bedtime or between meals to ensure an acidic environment for better assimilation.

Lactose: Calcium’s Ally in Infants

For infants, the lactose in milk plays a beneficial role in calcium absorption. Intestinal microbes break down lactose into acids, which lower the pH in the gut, making calcium more soluble and easier to absorb.

Amino Acids: Nature’s Calcium Carriers

Certain amino acids, particularly lysine and arginine, have been shown to enhance calcium absorption. This is why many calcium supplements are chelated, combining calcium with amino acids to improve uptake during digestion.

Exercise: Strengthening Bones and Absorption

Regular physical activity, especially weight-bearing exercises, not only strengthens bones but also appears to improve calcium absorption when combined with adequate vitamin D intake.

Factors Hindering Calcium Absorption

While some elements enhance calcium uptake, others can interfere with its absorption:

Phytic Acid: The Mineral Binder

Found in the bran coating of whole grains, phytic acid can bind to calcium and other minerals, forming insoluble compounds that the body cannot absorb. This can lead to calcium passing through the digestive system without being utilized.

Excessive Sodium Intake: The Calcium Depleter

High levels of sodium in the diet can interfere with calcium absorption and increase calcium excretion through urine. Reducing salt intake may help improve calcium retention and overall bone health.

Caffeine Consumption: The Calcium Diuretic

The caffeine found in coffee, tea, and many sodas acts as a mild diuretic, potentially causing increased calcium excretion before the body can fully utilize it. While moderate consumption is generally harmless, excessive intake may lead to reduced calcium absorption.

Smoking: The Silent Calcium Thief

Studies have shown that smokers often have reduced bone mass. While the exact mechanism is not fully understood, it appears that smoking interferes with calcium absorption in the intestines, potentially leading to weakened bones over time.

Celiac Disease: The Absorption Disruptor

Celiac disease, an inherited autoimmune condition characterized by gluten intolerance, can significantly impact calcium absorption. The disease alters the lining of the intestine, affecting the absorption of fat-soluble vitamins and minerals, including vitamin D and calcium. This makes celiac disease a significant risk factor for osteoporosis.

Optimizing Calcium Absorption Through Diet

To maximize calcium absorption, consider incorporating these dietary strategies:

1. Include calcium-rich foods in your diet, such as dairy products, leafy greens, and fortified foods.
2. Ensure adequate vitamin D intake through sunlight exposure, fatty fish, egg yolks, and fortified foods.
3. Limit consumption of foods high in oxalic acid, such as spinach, chard, and chocolate, which can reduce calcium absorption.
4. Be mindful of phytic acid content in whole grains and consider calcium-fortified alternatives if consuming large amounts of these foods.
5. Moderate caffeine and sodium intake to prevent excessive calcium loss.

Calcium Supplements: Maximizing Absorption

For those considering calcium supplements, here are some tips to enhance absorption:

• Choose calcium supplements that are easily soluble, as they dissolve more readily in stomach acid.
• Take calcium supplements with meals to take advantage of the increased stomach acid production.
• Consider calcium supplements that are chelated with amino acids for improved absorption.
• Spread calcium intake throughout the day, as the body can only absorb a limited amount at one time.
• Combine calcium supplements with vitamin D for optimal absorption.

Lifestyle Factors Affecting Calcium Utilization

Beyond diet and supplements, several lifestyle factors can impact calcium absorption and utilization:

Physical Activity: The Bone Strengthener

Regular weight-bearing exercise and resistance training not only strengthen bones but also appear to enhance calcium absorption. Aim for at least 150 minutes of moderate-intensity exercise per week.

Stress Management: Balancing Hormones for Better Absorption

Chronic stress can lead to elevated cortisol levels, which may interfere with calcium absorption and bone formation. Implementing stress-reduction techniques such as meditation, yoga, or deep breathing exercises can help maintain hormonal balance and support calcium utilization.

Alcohol Consumption: Moderation is Key

Excessive alcohol intake can interfere with calcium absorption and vitamin D metabolism. Limiting alcohol consumption to moderate levels (up to one drink per day for women and up to two drinks per day for men) can help maintain optimal calcium absorption.

Sleep Quality: Supporting Hormonal Balance

Adequate, quality sleep is essential for maintaining hormonal balance, including the production of growth hormone and melatonin, which play roles in bone metabolism. Aim for 7-9 hours of sleep per night to support overall health and calcium utilization.

Special Considerations for Calcium Absorption

Certain populations may need to pay extra attention to calcium absorption:

Postmenopausal Women: Increased Calcium Needs

After menopause, women experience a decline in estrogen levels, which can lead to accelerated bone loss. This group may benefit from increased calcium intake and should consult with a healthcare provider about appropriate supplementation.

Vegans and Vegetarians: Plant-Based Calcium Sources

Those following plant-based diets should be mindful of their calcium intake, as they may not consume dairy products. Good plant-based calcium sources include fortified plant milks, tofu processed with calcium sulfate, and leafy greens like kale and bok choy.

Individuals with Lactose Intolerance: Alternative Calcium Sources

People who are lactose intolerant may need to seek out alternative calcium sources or use lactase enzymes when consuming dairy. Lactose-free milk products, calcium-fortified foods, and supplements can help meet calcium needs.

Understanding the factors that influence calcium absorption is crucial for maintaining optimal bone health and overall well-being. By considering dietary choices, lifestyle factors, and individual health conditions, it’s possible to enhance calcium uptake and utilization in the body. Remember to consult with a healthcare provider before making significant changes to your diet or starting any new supplement regimen, especially if you have underlying health conditions or are taking medications that may interact with calcium metabolism.

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

Factors affecting Calcium Absorption in Body – By Dr.

Priyanka Joshi

Last Updated: Jan 10, 2023

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Dr. Priyanka JoshiDietitian/Nutritionist • 4 Years Exp.Ph.D – Food Science and Nutrition

Incorporating healthy foods in the diet is not enough. One should understand the factors affecting the absorption of nutrients from the food. Some factors are responsible for increased absorption of particular nutrients whereas some decrease its absorption.

Calcium is the hardest mineral to get absorbed in the body. 30-80 % of the dietary calcium is not getting absorbed in the adult body.

Check out some factors influencing calcium absorption in our body, these factors can be related to the hormone, amino acids, milk, and more:

1. Vitamin D: Vitamin d works in the digestive tract to absorb calcium into the bloodstream from the walls of the duodenum. Vitamin D also helps maintain normal blood calcium levels.
2. Parathyroid Hormone: It increases calcium transport across the membrane of intestinal cells.
3. Acid Environment: Hydrochloric acid secreted in the stomach during the process of digestion is required for the absorption of calcium in the duodenum. Calcium supplements could be taken with magnesium at bedtime or between meals due to the acid environment needed in the stomach to assimilate the calcium. Always consult a physician before beginning a new supplement regimen.
4. Milk Lactose: it favors absorption in infants. Lactose is acted upon by intestinal microbial flora to form acid which causes the lowering of ph which makes calcium more soluble.
5. Amino Acids: Supplemental calcium is often chelated, or combined with protein molecules called amino acids, to help the body absorb them during digestion. Lysine and arginine increase calcium absorption.
6. Exercise: Exercise along with Vitamin D intake helps calcium absorption thereby making bones strong.

Factors Decreasing Absorption of Calcium in Body

1. Oxalic acid phytic acid: Foods that are high in oxalic acids such as spinach, chard, and chocolate, reduce calcium absorption. Oxalic acid binds with the calcium to form a salt crystal, calcium oxalate which cannot be absorbed. Phytic acid, which is found in whole-grain foods and high-fiber foods, affects calcium absorption the same way.
2. Phosphorus: Too much phosphorus in the diet causes precipitation of calcium in the form of calcium phosphate.
3. Stress: Stress can have a negative effect on hcl production in the stomach and on normal digestive behavior in the body, and can, therefore, have a negative effect on calcium absorption.
4. Caffeine, drugs like anticoagulants, cortisone, and thyroxine reduce calcium absorption in the body.
5. Lack of exercise and vitamin d deficiency leads to decrease in calcium absorption.

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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.