Category: Vitamins

Introduction

Equine nutrition plays a central role in rearing of horses because they are non-ruminant herbivores. Horses rely on the fermentation processes to digest cellulose in their single stomach. Normally, horses feed on forages, concentrates, pellets, and supplements. Given that horses are non-ruminant herbivores, they take small portions of these types of feed several times a day to allow complete digestion of each portion. In this view, the understanding of nutritional requirements and metabolic mechanisms is essential in the formulation of equine nutrition. Horses require calcium, phosphorus, and vitamin D as macronutrients that are important in the formation and the growth of bones.

The proportions of calcium, phosphorus, and vitamin D in diet determine their respective nutritional importance because of metabolic interactions. Breidenbach, Revesz, and Harmeyer state that high doses of vitamin D increase excretion of calcium and phosphorus in horses (106). The statement implies that equine nutrition requires a delicate balance of calcium, phosphorus, and vitamin D because their metabolism interrelates. Therefore, the essay examines nutritional and metabolic importance of calcium, phosphorus, and vitamin D in equine nutrition.

Calcium

Metabolism and functions

Calcium is an essential mineral in the diet of horses because it is a major constituent of bones. Horses usually get calcium from forages and concentrates made from lucerne or manufactured supplements. When ingested, calcium undergoes absorption in the gastrointestinal system and the circulatory system distributes to diverse parts of the body, where bone formation and growth occur. The body distributes absorbed calcium into tissues and organs using blood and extracellular fluids, and removes excess calcium through intestinal secretion, kidneys, and skin (Schryver, Hintz, and Lowe 102).

Horses need calcium in abundance for they require strong bones for them to adapt to their functions. For example, racing horses require enough calcium in their bodies for the formation and maintenance of strong bones because their bones are prone to wear and tear during rigorous performances. Rourke, Kohn, Levine, Rosol, and Torobio state that calcium has structural importance in horses because it forms the skeletal system that supports horses against gravity, protects internal organs from physical damage, and hosts diverse structures in their respective positions (197). Hence, the structural importance of calcium enables horses to have stout bodies with the capacity to perform numerous functions such as racing and transportation.

Calcium also has physiological importance among horses because it causes muscle contraction, regulates locomotion, boosts cardiac functions, and facilitates gastrointestinal peristaltic movements. Regarding muscle contraction, calcium interacts with actin and myosin muscle fibers, which are responsible for the contraction and relaxation of skeletal muscles. Since horses perform strenuous physical activities such as running, they require calcium to aid in the contraction of muscles.

Horses with low levels of calcium in their bodies are usually very weak because skeletal muscles do not have sufficient amounts of calcium to cause contraction of muscles and bring about skeletal movement. In this view, calcium regulates locomotion among horses as high concentration of calcium in the body increases the potential of locomotion, while low concentration of calcium in the body reduces the potential of movement. As calcium causes contraction of muscles, it mediates the contraction of involuntary cardiac muscles, and thus, determines the rate of heart beat. In the gastrointestinal system, calcium facilitates peristaltic movement, which is central to the digestion process. Overall, calcium is important because it mediates contraction of different types of muscles as aforementioned.

In the body, calcium regulates physiological activities such as blood clotting process, functions of transmembrane channels, transmission of impulses, and enzymatic reactions. During the blood clotting process, calcium interacts with clotting factors in the cascade process, which eventually leads to the formation of a blood clot. The absence or low level of calcium causes the loss of blood when an injury occurs because blood takes unusually long period to clot (Rourke et al. 198).

Hence, horses require calcium to speed the blood clotting process and promote healing of wounds in case of injuries. Since transmembrane channels regulate the entry and exit of substances in and out of the cells, calcium takes part in regulating these channels. Primarily, calcium maintains integrity of cell membranes as it allows communication among cells via transmembrane channels. In conjunction with potassium and sodium, calcium also influences the transmission of nerve impulses in the body. Calcium acts as a cofactor, which regulates activity of enzymes in cellular processes, such as cell division, growth, and motility.

Homeostasis of calcium

Horses normally experience frequent instances of hypocalcemia and hypercalcemia when compared to other mammals. Homeostatic mechanism regulates the level of calcium in blood and tissues within a narrow range. According to Rourke et al., calcitonin, vitamin D, and parathyroid hormone are three hormones, which are responsible for homeostatic regulation of calcium in horses (176).

When calcium levels are very high, thyroid gland releases equine calcitonin, which causes the reduction of calcium levels in serum and stimulates storage of calcium in bones. In contrast, a low level of calcium induces the release of parathyroid hormone by the thyroid gland, which causes renal reabsorption, synthesis of vitamin D, and bone resorption (Matsuzaki and Dumont 232). Given that horses often experience imbalances in the levels of calcium, they utilize these hormones in restoring the imbalances and optimizing the functions of calcium in their bodies. Therefore, assessment of the nutrition and metabolism of calcium indicates that it has important structural and biochemical functions in horses.

Phosphorus

Metabolism and functions

Phosphorus is an important mineral that horses require for the growth and development of healthy bones and teeth. Calcium combines with phosphorus in the development of strong bones and teeth, which enable horses to adapt to their functions of racing and chewing forages respectively. Owing to the importance of phosphorus in the growth and development of horses, industries that manufacture feeds incorporate phosphorus as a macronutrient. Since horses need strong bones, they require supplements of calcium and phosphorus in their diets. Schryver, Hintz, and Craig recommend that mature horses need an average of 17g of phosphorus daily for maintaining physiological functions in their bodies (1257).

Hence, daily dietary intake of horses must contain appropriate amounts of phosphorus, which meet physiological functions. Horses that consume phosphorus in their diet regularly have strong skeletal structure because phosphorus is a constituent of bones and teeth (Lawrence 209). Evidently, phosphorus is an essential macronutrient for its deficiency leads to poor development of bones and teeth.

Phosphorus is an important constituent of biochemical energy in the form of adenosine triphosphate (ATP). The performance horses utilize ATP in the generation of the required horsepower. Lawrence asserts that horses require sufficient energy in form of ATP for muscle contraction, which they obtain from carbohydrates (206). ATP is a biochemical energy that contains phosphorus, and its function is to transfer energy from one cell to another cell during contraction of muscles. Additionally, phosphorus is an important component of cyclic adenosine monophosphate (cAMP), a chemical messenger that mediates a number of cellular activities.

Adenyl cyclase is an enzyme that converts ATP into cAMP with the loss of pyrophosphate. Matsuzaki and Dumont state that cAMP regulates the activity of the parathyroid gland in the production of parathyroid hormone, which in turn regulates the level of calcium in the body (227). In this view, phosphorus indirectly regulates activity of the parathyroid gland and metabolism of calcium in the body.

Homeostasis of phosphorus

The metabolism of phosphorus occurs normally like calcium or any other mineral in the body of horses. The intake of phosphorus through diet or supplements increases the level of phosphorus in blood after absorption in the intestines. The blood transports phosphorus to bones, teeth, and tissues, where their metabolism occurs. Horses excrete excess phosphorus in urine and feces. Hence, diet, renal excretion, and fecal excretion provide homeostatic mechanisms that maintain the level of phosphorus in the body at the required level. The homeostatic mechanisms show that renal or urinary excretion of phosphate is proportional to dietary intake of phosphorus (Schryver, Hintz, and Craig 1261).

The direct relationship between renal excretion and dietary intake of phosphate indicates that kidneys play a central role in the homeostatic mechanisms. According to the findings of an experiment, the endogenous fecal excretion of phosphorus among horses is not proportional to the dietary intake of phosphorus (Schryver, Hintz, and Craig 1261). The findings show that endogenous fecal execration does not play a significant role in phosphorus homeostasis.

Vitamin D

Metabolism and functions

As one of the vitamins that horses utilize, metabolism of vitamin D is unique. Once ingested, vitamin D is inactive, and therefore, goes into the liver where hepatic enzymes convert it into an active form of vitamin D called 25-OH-D₃ through the process of hydroxylation. DeLuca and Schnoes report that 25-hydroxylase is a hepatic enzyme that activates vitamin D by hydroxylating its 25-crabon (625). Without hydroxylation in the liver, vitamin D remains inactive in the body, and thus, becomes physiologically deficient. In this view, the liver plays a central role in the metabolism and the use of vitamin D.

The active form of vitamin D, 25-OH-D_3, then circulates in the bloodstream and moves to the kidneys where further hydroxylation takes place. When the concentration of 25-OH-D₃ increases, parathyroid hormone induces the synthesis of 25-hydroxyvitamin-1α-OH hydroxylase in the kidneys, which catalyzes conversion of 25-OH-D₃ into 1α,25-(OH)_2-D₃. The hydroxylation of 25-OH-D₃ in the kidney gives an active form of vitamin D, 1α,25-(OH)_2-D₃, which performs diverse cellular and systemic functions. According to DeLuca and Schnoes, 24-hydroxylase degrades both 1α,25-(OH)_2-D₃ and 25-OH-D₃ into 1α,24,25-(OH)_2-D_3, and 24,25-OH-D₃ respectively (642). Therefore, horses excrete vitamin D in the form of 1α,24,25-(OH)_2-D_3, and 24,25-OH-D₃ through the kidneys under the control of parathyroid hormone.

Vitamin D is an important vitamin because it regulates metabolism of calcium and phosphorus. In its regulatory function, vitamin D enables intestines to absorb calcium and phosphorus from the consumed food. Given that concentration and electrical gradient prevent the absorption of calcium and phosphorus in the intestines, vitamin D alters the property of intestinal membranes and allows the movement of these minerals against the concentration and electrical gradient (Breidenbach, Revesz, and Harmeyer 105).

Thus, a deficiency of vitamin D causes physiological deficiency of calcium and phosphorus. Essentially, absorption of calcium and phosphorus would not take place despite their intake in the diet. Vitamin D also is important in the formation and development of bones because it promotes mineralization process. DeLuca and Schnoes explain that vitamin D has the capacity to alleviate osteomalacia and rickets because it avails calcium to mineralization sites in the skeletal system (649). In this view, vitamin D mediates deposition and resorption of bones, the processes that are central to the homeostasis. In tissues, vitamin D is very important because it regulates cell division by inhibiting proliferation of cells and enhancing differentiation.

Homeostasis of vitamin D

The level of vitamin D in the body is subject to homeostatic mechanism that is under the regulation of calcium, phosphorus, and parathyroid hormone. DeLuca and Schnoes explain that when the level of calcium in the body is low, parathyroid hormone elicits synthesis of vitamin D, which in turn elicits intestines to increase the absorption of calcium (632). Moreover, synergistic effect of vitamin D and parathyroid hormone increases plasma calcium by increasing bone resorption and reabsorption of calcium in the kidneys. When the level of phosphorus is low in the body, there is stimulation of vitamin D synthesis, which is independent of parathyroid hormone.

In contrast, when the levels of calcium and phosphorus are high, the level of parathyroid hormone goes down, and hence, no synthesis of vitamin D. The resultant effect is decreased reabsorption of calcium and phosphorus in the kidneys and increased mineralization of bones. DeLuca and Schnoes observe that vitamin D acts as a hormone that mobilizes calcium and transports phosphorus (632). Thus, the homeostatic mechanism shows that vitamin D plays a central role in the metabolism of calcium and phosphorus in horses.

Calcium, Phosphorus, and Vitamin D Interactions

The influence of calcium

The intake of calcium and phosphorus in various forms of diets leads to interactions that influence their respective metabolism. Calcium intake influences the metabolism of phosphorus in the body in terms of excretion and retention. Schryver, Hintz, and Craig report the findings that when ponies consume a diet with high calcium, the absorption of phosphorus increases (1260). The findings indicate that calcium increases the absorption of phosphorus, but decreases its excretion among ponies. Schryver, Hintz, and Lowe explain that renal excretion of phosphorus decreases because a high level of calcium stimulates bone formation, which increases the requirement of phosphorus (103). Therefore, it is evident that calcium influences the metabolism of phosphorus in terms of excretion, retention, and uses among ponies.

The influence of phosphorus

The level of phosphate in the diet influences the metabolism of calcium in horses. A study done among ponies fed with a diet that has high levels of phosphorus and adequate amounts of calcium shows that phosphorus inhibits absorption and decreases the retention of calcium (Schryver, Hintz, and Lowe 103). Assessment of each pony shows that the level of plasma phosphorus negatively correlates with the level of plasma calcium. High plasma phosphorus or high phosphorus diet increases turnover rate of bones as the processes of bone resorption and deposition hastens. Schryver, Hintz, and Lowe found out that an increase in plasma phosphorus increases the rate of bone resorption by 83% and increases the rate of calcium deposition by 40% (103).

The interaction of calcium and phosphorus causes secondary hyperparathyroidism among horses. The deficiency of calcium coupled with high plasma phosphorus predisposes horses to secondary hyperparathyroidism (Hintz and Cymbaluk 258). The finding implies that the diet with high phosphorus influences metabolism of calcium during bone resorption and calcium deposition. Overall, phosphorus decreases retention of calcium and hastens the turnover rate of bones.

The influence of vitamin D

In horses, the metabolism of calcium and phosphorus is under the influence of vitamin D. High dosage of vitamin D increases renal excretion of calcium and phosphorus in horses. The findings of a study show that toxic levels of vitamin D causes a twofold increase in the rate of renal excretion of calcium and a 20-fold increase in the rate of phosphorus excretion (Breidenbach, Revesz, and Harmeyer 106).

The findings imply that vitamin D has significant influence on the levels of calcium and phosphorus, and thus, an important factor to consider in equine nutrition. Despite the fact that vitamin D stimulates intestines to absorb calcium and phosphorus, high level of vitamin D is toxic because it increases excretion of calcium and phosphorus. Owing to the influence of toxic level of vitamin D, equine nutrition should have minimal amounts of vitamin D, which are only sufficient to promote absorption of calcium and phosphorus. The increased excretion of calcium and phosphorus in response to high concentration of vitamin D is under the influence of parathyroid hormone.

Conclusion

Calcium, phosphorus, and vitamin D are equine macronutrients, which have important roles in the growth and development of horses. Calcium and phosphorus are major constituents of bones and teeth. Given that horses perform extraneous activities such as race performance and transportation, they require strong bones. The metabolism of calcium and phosphorus is under hormonal regulation of parathyroid hormone. Vitamin D also aids in the formation of bones because it mobilizes deposition and resorption of calcium and phosphorus. Homeostatic mechanisms of these minerals indicate that their levels in the body influence their metabolism. Overall, horses require a regulated dietary intake of calcium, phosphorus, and vitamin D at the appropriate proportions for them to have optimal metabolism and functions.

Works Cited

Breidenbach, Alexander, Balazs Revesz, and John Harmeyer. “Effect of high doses of vitamin D on calcium and phosphate homeostasis in horses: A pilot study.” Journal of Animal Physiology and Animal Nutrition 80.1 (1998): 101-107. Print.

DeLuca, Hector, and Henrich Schnoes. “Metabolism and mechanism of action of vitamin D.” Annual Review of Biochemistry 45.1 (1976): 631-666. Print.

Hintz, Harold, and Nadia Cymbaluk. “Nutrition of the horse.” Annual Review of Nutrition 14.1 (1994): 243-267. Print.

Lawrence, Laurie. “Nutrient needs of performance horses.” Revista Brasileira de Zootecnia 37.1 (2008): 206-210. Print.

Matsuzaki, Shin-ichiro, and Henri Dumont. “Effect of calcium ion on horse parathyroid gland adenyl cyclase.” Biochimica et Biophysica Acta 284.1 (1972): 227-234. Print.

Rourke, Kelvin, Craig Kohn, Alan Levine, Thomas Rosol, and Ramiro Torobio. “Rapid calcitonin response to experimental hypercalcemia in healthy horses.” Domestic Animal Endocrinology 36.4 (2009): 173-224. Print.

Schryver, Herbert, Harold Hintz, and John Lowe. “Calcium and phosphorus inter-relationship in horse nutrition.” Equine Veterinary Journal 3.3 (1971): 102-109. Print.

Schryver, Herbert, Harold Hintz, and Paul Craig. “Phosphorus metabolism in ponies fed varying levels of phosphorus.” The Journal of Nutrition 101.1 (1971): 1257-1264. Print.

Introduction

Micronutrients are the elements that help organisms function without interruptions. As a rule, people get them together with food and drinks. They may be found in fruits, vegetables, meat, fish, and other products. Their toxicity or deficiency may pose a serious threat to people’s health conditions, and it is useful to know their symptoms (Capone, 2019). The paper describes the symptoms of toxicity and deficiency of iodine and vitamin C as well as their impact on people’s organisms.

Main body

Iodine is a micronutrient that helps the thyroid gland work without any deviations. It is contained in fish, mussels, beet, spinach, tomatoes, carrots, potatoes, beans, and many other products. Its deficiency violates the work of the thyroid, which provokes weakness, headaches, gaining weight, memory, eyesight, and hearing violations (Capone, 2019). Iodine toxicity is as dangerous as its deficiency since it is quite a toxic element, and one should be careful when taking iodine-containing medicines or products. It is characterized by stomachaches, vomiting, and other symptoms of intoxication. The most widespread disease provoked by iodine toxicity is the grave disease. When taken appropriately, iodine helps prevent diseases of the nervous system, such as memory and concentration degradation and many others.

Vitamin C is one of the most important micronutrients since it protects people from infections and heart diseases such as heart attacks or thrombosis. Vitamin C is contained in lemons, grapefruits, oranges, spinach, black currant, and other fruits and vegetables. The most common symptoms of its toxicity concern stomach discomfort, intoxication, kidney stones, or headaches (Capone, 2019). Vitamin C deficiency is usually characterized by bleeding gums; hair falls, the fragility of nails, and frequent colds.

Conclusion

To conclude, when speaking about micronutrients, it is necessary to remember that every person has his own daily norm of them. It may be counted only in a healthcare institution by an experienced physician. Hence, one should consult with a specialist and take medical tests before taking vitamins. Wrongly prescribed microelements cause changes in people’s bodies and a lot of them are irreversible and harmful to people’s health.

Reference

Capone, K. (2019). The ABCs of nutrient deficiencies and toxicities. Pediatric Annals, 48(11). Web.

Vitamin D plays a significant role in regulating phosphorus and calcium absorption in our bones. Far from this regulation, the nutrient is also essential in facilitating communication among cells within our bodies. The other significance of vitamin D in the body is that it can be manufactured when exposed to sunlight. These characteristics distinguish the vitamin from other nutrients since it can be obtained from sun exposure apart from food and dietary supplements. Compared to other nutrients, what characterizes vitamin D makes it a super nutrient.

What sets vitamin D apart from the other nutrients and arguably makes it a super nutrient is that, unlike other nutrients, it can be obtained by exposure to the sun. Exposure to the sun is the most effective way the vitamin can be obtained (Klioze, 2017). The potential magic associated with the nutrient is that it acts as a potential hormone in over a dozen of cells and tissues throughout the body. In so doing, the vitamin helps the body regulate essential gene expression and rapidly activates the already-expressed proteins and enzymes (Klioze, 2017). For example, in the heart, vitamin D binds to a certain receptor of the same vitamin, generating a calming protective effect.

With a considerable amount of research on the nutrient focusing on the significance of the vitamin on overall health, some epidemiological studies have uncovered a deficiency torrent of vitamin D. Based on the read report; findings show that between 50 and 75 percent of Americans have insufficient vitamin D levels in their bodies (Feldman et al., 2018). A growing body of evidence shows that an individual’s chance for optimal health is increased if the nutrient levels are adequate and vice versa. However, important to note is that “Just because low vitamin D and disease are correlated does not mean that one causes the other” (Feldman et al., 2018). Contrary, the same scientific reports have shown that approximately 75 percent of breast and colon cancer can be prevented by maintaining sufficient vitamin D levels (Klioze, 2017). Several reasons exist why vitamin deficiency is widespread in the U.S. and the world over.

Unlike other vitamins, vitamin D is one of the few nutrients the body can make. However, compared to the others, 40 percent of body exposure to ultraviolet B rays, between 15 and 30 minutes, results in the production of 20,000 IU of the nutrient (Klioze, 2017). Shocking statistics reveal that significantly few foods and supplements have the same amounts of vitamin D occurring naturally. Except for sardines, mackerel, salmon, and tunas, daily consumption of any other food results in insufficient vitamin D amounts in the body. Ironically, a one-eight-ounce of milk glass can only give 100 IU of the nutrient with a similar amount acquired in a bowl of fortified cereals (Feldman et al., 2018). Combined, both a glass of milk and cereals can only generate 200 IU of vitamin D, a one-tenth amount that can be acquired from thirty minutes under the sun (Feldman et al., 2018). Hence, it becomes physically impossible to eat your way out of vitamin D deficiency.

Vitamin D is arguably fast becoming a super nutrient, with its importance growing exponentially in the past few decades. Scientific research shows that insufficient vitamin D can be associated with widespread health consequences. However, as shown, just because low vitamin D and disease are correlated does not mean that one causes the other. Contrary, by maintaining sufficient vitamin D levels, some major health complications can be prevented.

References

Feldman, D., Pike, J. W., & Bouillon, R. (2018). Vitamin D: Volume 1. Elsevier.

Klioze, S. (2017). Vitamin D. YouTube. Web.

Introduction

A vitamin that naturally occurs in many types of food, Vitamin B6 is a collective name for six different vitamers, all with vitamin 6 activity¹. Though it may be not as commonly known as other vitamins, it still is essential for the proper functioning of human body. In order to maintain the proper percentage of Vitamin B6 in the patient’s body, it is imperative that the dietary allowances of the vitamin should be in direct proportion to the patient’s age; more to the point, pregnant women will need a greater quantity of the vitamin than other patients, which means that the emphasis must be put on fruits (banaa), vegetables, fish (tuna) and cereals.

Vitamin B6: Overview

The dietary reference intakes (DRIs) established by the FNB are the recommended reference values for the intake of the vitamin¹. The recommended dietary allowance (RDA) is the most important DRIs¹. For infants aged between 0 and 6 months, the RDAs are set at 0.1mg for both genders¹. Between 7 and 12 months, infants should be given 0.3mg while those aged 1 to 3 years should be given 0.5 mg¹. For children aged 4 to 8 and 9 to 13, the RDA for both genders are 0.6mg and 1.0 mg respectively¹.

Between 14 and 18 years, the RDAs for males is 1.3 while that for females is 1.2 mg. Between 19 and 50 years, both genders’ RDA is 1.3mg while that of people aged 50 and above is 1.7 mg (males) and 1.5 mg (females)¹. Pregnant and lactating females aged between 14 and 50, the RDA is 1.9 mg and 2.0 mg respectively¹.

This biosynthetic route is well defined in E. coli. In this process, the substrate 3-hydroxyl-1-aminoacetone phosphate undergoes a four step synthetic pathway from D-erythrose 4-phosphate². In the first step, the compound is oxidated to D-erythronate 4-phosphate by its respective dehydrogenase enzyme (GapB), which uses NAD redox factor².

In the second step, the D-erythronoate 4-phosphte undergoes a process of oxidation under the action of its respective enzyme PdxB and the NAD cofactor to produce (3R)-3-hydroxy-2-oxo-4-phosphonooxybutanoate². Then, the enzyme PdxF catalyzes the PLP-dependent transmission from the product of the second oxidation to glutamate, which results into the formation of 4-hydroxy-L-threonine phosphate (HTP)².

Then, HTP undergoes an oxidative decarboxylation under the influence of enzyme PdxA to form 3-hydroxy-1-aminocetne phosphate. It is believed that the process takes place in two steps². First, alcohol undergoes a nicotinamide-dependent oxidation at the α-position. Secondly, the resulting α-ketoacid is decarboxylated to form the 3-hydroxy-1-aminocetne phosphate².

Then, the unstable 3-hydroxy-1-aminocetne phosphate is changed to PNP by PNP synthase. The enzyme PNP oxidase oxidizes PNP to form PLP, the active form of vitamin B². In this pathway, glutamine is first hydrolyzed into ammonia under the catalytic action of Pdx2 using the Glu-His-Cys triad of catalysis. The formed ammonia diffuses to the active site of Pdx1 through the hydrophobic channel². Here, PLP is synthesized from glyceraldehyde 3-phosphate and D-ribose 5-phosphate, ending the process.

Two pathways, A and B, are involved³. Pathway A has 8 steps for degrading pyridoxine. First, pyridoxine is oxidized to pyridoxal by enzyme pyridoxine 4’-oxidase². NAD-dependent pyridoxal dehydrogenase enzyme oxidizes pyridoxal to produce 4-pyridoxolactone, which also hydrolyzed². This product undergoes oxidation to form 2-methyl-3-hydroxypyridine-4-carboxylic acid in two steps, the first of which is catalyzed by FAD dependent pyridoxic acid 4-dehydrogenase enzyme and he second by a NAD depedent-5-formaly-3-hydroxyl-2-methylpyridine-4-carboxylic acid dehydrogenase².

Then, the acid is decarboxylated to form 2-methyl-3-hydroxypyridine-5-carboxylic acid under the catalytic action of an enzyme that depends on the presence of magnesium ions². The product then undergoes an oxidative opening of the ring (2-(N-acetamidomethylese) succinic acid). A FAD dependent 2-methyl-3-hydroxypyridine-5-carboxylic acid oxygenase catalyzes the succinic acid to form acetate, carbon dioxide, ammonia and succinic semialdehyde, which completes the pathway².

On the other hand, the B pathway has only five steps. First, pyridoxine is oxidized under the catalytic action of FAD-dependent pyridoxine-5-dehydrogenase enzyme to form isopyridoxal, which is then oxidized to form 5-pyridoxolactone. This product is further oxidized to form 5-pyridoxic acid under the enzyme 5’-lactonase action². The 5-pyridoxic acid undergoes a process of oxidative ring opening under the catalytic action of FAD dependent 5-pyridoxic acid oxegenase, resulting into 2-hydroxymethyl-(N-acetomidomethylene) succinic acid. The final step involves the hydrolysis of the succinct acid to form acetate, carbon dioxide and ammonia².

Conclusion

Because of the need to maintain the rates of the Vitamin B6 in the patient’s body in accordance with the patient’s age and gender (the older the patient is, the greater amount of the vitamin must be consumed; pregnant women must be provided with 2.0 mg as opposed to the rest of the patients (1.9 maximum)), it is crucial that the patient’s diet should include vegetables, fruits (specifically bananas), fish (especially tuna and salmon) and cereals.

As the vitamin in question facilitates the biosynthesis of several essential neurotransmitters, including adrenalin, noradrenalin, gamma-aminobutyric acid GABA, etc., its rates in the human body must be maintained at a constant level, which is calculated based on the patient’s age. With the choice of a diet based on vegetables, fish, chicken meat and fruit, the patient will be able to regain the proper rates of Vitamin B6 within a relatively short amount of time.

References

1. Vitamin B6: Dietary supplement fact sheet. The National Institutes of Health. 2014. Web.
2. Mukherjee T, Hanes J, Tews I, Ealick S E, Begley T P. Pyridoxal phosphate: Biosynthesis and catabolism. Biochimica et Biophysica Acta 2011; 1814(11): 1585–1596.
3. Salvo M L d, Contestabile R, Safo M K. Pyridoxal phosphate: Biosynthesis and catabolism. Biochimica et Biophysica Acta 2011; 1814(11): 1597–1608.

Introduction

There are many ways for people to improve their health, stabilize vital signs, and control or prevent diseases and complications. Vitamins turn out to be a good source of natural help, and it is necessary to know about their functions, mechanisms of actions, and sources. Vitamin B12, also known as cobalamin, is a water-soluble vitamin that contributes to blood cell formation, the work of the nervous system, and metabolism (Ritter et al. 338). In other words, to function properly, the body needs of vitamin B12 that can be obtained from meat, fish, and different dairy products. In this research paper, special attention will be paid to vitamin B12, its mechanism of action, administration, and sources in order to identify possible risks and benefits associated with this substance.

Mechanism of Action and Administration

Vitamin B12 is characterized by a number of positive qualities and outcomes for human health. The recommended dose of vitamin B12 for humans is 2-3 mg per day (Ritter et al. 338). There are two major chemical reactions that may be provoked by this vitamin. The first reaction includes the conversion of methyl-FH₄ to FH₄ due to its metabolic activities and relation to DNA synthesis. Vitamin B12 lowers the level of plasma homocysteine concentration and predicts unpleasant vascular effects (Ritter et al. 338). This vitamin becomes a methyl donor for the body, and its deficiency may result in depleting the folate polyglutamate enzymes that play a crucial role in DNA synthesis. Ritter et al. also identified another mechanism of action that is connected to the isomerization of methylmalonyl-CoA to succinyl-CoA (338). This process contributes to converting propionate to succinate and the possibility of cholesterol and other fatty acids to produce more energy. Due to its malabsorption, injections are recommended as the best administration method. As a rule, no unwanted or harmful effects are observed in patients, and long-term therapy with vitamin B12 is prescribed.

Sources

Animals are the major sources for vitamin B12 synthesis, and plants are not appropriate for this procedure. The meat (particularly, liver), eggs, and milk of such animals like cows or sheep turn out to be good sources of this substance (Watanabe and Bito 148). These animals are herbivores, meaning that they eat plants (e.g., grass) that is free of B12. In their stomachs, there are several chambers with a number of microorganisms, and one of them is B12-synthesizing bacteria (Watanabe and Bito 149). As soon as vitamin B12 is absorbed, it is transferred into the blood and saved in the liver, animal muscles, or milk (Watanabe and Bito 149). Finally, B12 can be present in dietary supplements, medications, and natural food.

Risks and Benefits

As a part of a large vitamin group, B12 has its strong and weak aspects. For example, it aims at converting energy from food and stabilizes the work of the body. Increased blood circulation, the formation of DNA, and prevention of brain atrophy are three more positive outcomes of taking vitamin B12. In addition, people who take this vitamin regularly report reduced eye problems and depression cases. At the same time, people should remember that interaction of B12 with other drugs is not completely studied, and diabetic or chronic patients may be at risk.

Conclusion

In general, regarding all positive and negative aspects of vitamin B12, this substance remains an important component of a healthy lifestyle. It is easy to find this vitamin in everyday products and consume them carefully. B12 has a number of positive outcomes of the nervous system, blood circulation, and mental health. Vitamin deficiency is possible and results in certain psychological, physical, and nervous problems. Still, its recognition on early stages and effective treatment can be offered to any patient.

Works Cited

Ritter, James M., et al. Rang & Dale’s Pharmacology. 9th ed., Elsevier Health Science, 2018.

Watanabe, Fumio, and Tomohiro Bito. “Vitamin B12 Sources and Microbial Interaction.” Experimental Biology and Medicine, vol. 243, no. 2, 2018, 148-158.

Data Collection

Table 1:Recording raw data

Date Processing

Table 2: Processing raw data

In order to determine the concentration of vitamin C in the homogenate, approximately 1 ml of the vitamin C solution was transferred to a test tube. Four test tubes containing 1 ml of vitamin C was setup as replicates. To each test tube, 6 drops of 2% starch solution was added, after which 0.01 M aqueous iodine solution was added to each test tube drop by drop, until the color of the homogenate turned black. The number of drops added to each test tube was taken note of and was used for further analysis. The results of this step of the experiment are presented in Table 1 for data collection.

The concentration of vitamin C was calculated by multiplying the number of drops of 0.01 M aqueous iodine solution that was introduced to each of the homogenate in order for the homogenate solution to turn black, by 120. The results of the calculations are presented in Table 2 of data processing. The results are also presented in a column graph, which directly shows that the number of drops of 0.01 M aqueous iodine solution is positively correlated with the concentration of vitamin C in the homogenate. It should be understood that the constant factor in this experiment is the amount of starch in the solution, which is 2% in concentration. Thus, the concentration of vitamin C in each solution influences the number of iodine drops that are needed in order to change the color of the homogenate solution to black. The presence of iodine in a solution triggers the hydrolysis of starch and thus results in the change of color of the solution.

Conclusion and Evaluation

Conclusion

This experiment has allowed us to learn how to prepare a vitamin C solution through the process of homogenization and collecting the homogenate or solution in a beaker. In addition, the experiment also allows us to determine the concentration of vitamin C in a solution through the use of color reactions using an iodine solution of determined concentration. Based on the data we collected, we can show that the amount of vitamin C can be calculated from the number of drops of iodine that was added to the homogenate + starch solution, in order to turn the color into black, which indicates that the starch was hydrolyzed. Based on the data that is presented earlier in Table 2, it shows that more iodine is needed when a vitamin C solution is much more concentrated.

Limitations/Sources of Error

The procedure is straightforward yet there may be steps that could affect our results. Firstly, the size of the drops of iodine may be different, depending on the pressure that is introduced to the pipette. Such discrepancies may be different when another individual adds the iodine to the vitamin C solution. In addition, the rate of dropping may also influence the counting of drops of iodine that is being added to the homogenate solution. If iodine is added at a very fast rate, the counting of iodine drops may be erroneous and if the iodine is added slowly, a better counting of iodine drops will be more precise. There may be fewer errors in the experiment if the dropper used was clean so that there would not be contaminants in the solution. It would have been better if the iodine was introduced in constant volumes in micro-liters using a micropipette so that all drops are precisely measured. For example, the experiment may employ that addition of iodine in 10 micro-liter gradations, instead of simple pipette drops. The use of a micropipette may allow the results to be more accurate in the volume of iodine that is introduced to each test tube. The same method of using a micropipette may also be used for the amount of 2% starch that is added to each vitamin C solution in order to avoid discrepancies in the volume added in the experiment. The purity of the vitamin C solution may also affect the readings of this experiment, wherein there may be impurities that were accidentally included in the vitamin C solution, thus lowering or increasing the amount of iodine that was needed in order to achieve the black color of the solution. Another factor that may affect the experiment is the cleanliness of the glassware, wherein the surface of the test tubes may contain remnants of detergent which may affect the reaction of iodine to the starch present in the vitamin C solution.

Suggestions for further investigations

Other investigations that may be conducted could possibly include fresh strawberries and bottled strawberries, and we can test how temperature affects the vitamin C concentration of the two types of strawberries (fresh versus bottled). From the two sources, we transfer a certain amount of juice to each to three tubes to be kept at room temperature, and we may heat the test tube to 40 degrees once and 60 degrees another time. In addition, we can perform the same procedure on vitamin C tablets versus the chewing vitamin C gum or chewable tablets such as Flintstones, in order to determine vitamin C concentrations in these items. The amount or concentration of vitamin C may also be checked in particular fruits such as grapes, apples and oranges. Even vitamin-supplemented bottled water can be tested for vitamin C content.

Vitamin A is a term used to refer to a large number of similar compounds, known as retinoids.Vitamin A found in food from animal is usually referred to as preformed Vitamin, Retinol and retinal is a good example. Vitamin A found in fruits and vegetable is referred to as Provitamin A carotenoids, these vitamins A are converted into retinol in the body where one molecule of beta carotene produces two molecule of Vitamin A. The body usually obtain vitamin by manufacturing it from carotene found in vegetable such carrots or by absorbing it from animal products of organism that eat plants. Vitamin A is stored in the fat tissue and carried through out the body by fat.

Vitamin A has a wide variety of use to the human body. This includes Vision, healthy skin, immune defenses, bone and body growth, reproduction and cell development. Vitamin A compound is used in the conversion of light’s reception in the eye retina for brain assimilation to convey a picture. When a light strike the eye, one form of vitamin A send a signal to the brain indicating that light is striking the eye, which leads to eye adjustment depending on the nature of light. Vitamin A also helps in boosting the immune system, protecting us from infections. White blood cells are stimulated by vitamin A increasing the antibodies alertness. In pregnant women, Vitamin A helps in embryonic development, fast tissues repair and maintenance of normal vision, lack of which can lead to night blindness. Vitamin A has also been proven to reduce cervical, breast and colon cancer as it inhibit tumor development.

There are two main sources of Vitamin A, animal source and vegetable source. Eggs, beef, chicken liver, fish liver oils, whole milk, cheese and butter are some of the main source of Vitamin A derived from animal products. Carrots, sweet potatoes, apricots, spinach, pumpkins, leafy vegetables, grapefruits and broccoli are some of the major source of beta carotene that is converted to vitamin in the liver. Vitamin A supplements are available in the United Kingdom market and act as another source for vitamin A.

In the United Kingdom, vitamin A supplements are given to children diagnosed with measles and any other child over the age of 5 months who has been hospitalized with any other medical conditions. Patients suffering from Celiac and Crohn’s diseases have limited vitamin A absorption ability in their body. As such they require vitamin A supplements to cater for their body needs. Vegetarians need provitamin A cateroids and as such, vitamin supplements are a good source for vitamins A.

Vitamin A is very essential in human body, it contribute greatly to the Vision, healthy skin, and immune system as it stimulates the activities of white blood cells in the body. In pregnant women, it helps in faster tissue repairs and prevents night blindness. Carotene found in Vegetables such as carrots and spinach is the main source of Provitamin A and animal products such as chicken liver and milk are a good source of preformed vitamin A.

Introduction

This assignment shall suggest appropriate procedures for the determination of vitamin c in the manufactured products given. The procedures shall be useful in determining vitamin C in sample A-which contains a selection of old products (a lemon, orange, and blackcurrant drinks) and sample B-which contains a selection of new products (a lemon, orange and blackcurrant drink).The investigation allows someone to know which brand or which type of soft drink contains less, more or no vitamin C. the results are then compared and interpreted.

The basic procedure described here can be applicable to all types of soft drinks. The process of determination of ascorbic acid involves titration which is usually done with either iodine or blue dye. This experiment will use the blue dye Dichlorophenolindophenol (DCIP) as the indicator.

Experiment

Theory

The blue dye used in this experiment is the 2, 6 dichlorophenolindophenol (2, 6 DPIP).It is blue in neutral alkaline solution and red in acidic condition. Its reduced form is colorless. When titrating an acidic solution against (2, 6 DCIP) the blue reagent turns colorless at the presence of ascorbic acid. When all the acid has been consumed any excess dye turns the solution pink. (Rastogi, 2005).

Assumption

1. Only the ascorbic acid or vitamin C in the drink will react with the dye.
2. The reduction of vitamin C will be negligible. This is because Vitamin C decomposes very fast when exposed to light and oxygen.

Apparatus

Pipettes (10ml). Burette, pipette filler, filter paper, volumetric flask, beaker, conical flask, filter tunnel and flat bottomed flask.

Chemicals

A control containing a solution of known amount of vitamin C, blue dye and a selection of old and new products (lemon, orange and blackcurrant drink)

Procedure

Standardization of blue dye:

1. About 30.0 cm³ of standard ascorbic acid (vitamin C) is solution is pipetted into a conical flask.
2. The blue dye is then titrated rapidly from a burette.
3. The end point is then taken to be when the dye turns colorless.

Titration:

1. The blue dye is diluted to about 1.00 dm³ of the solution
2. About 15.0 cm³ of sample a is (lemon, juice or black currant drink) is pippetted to a conical flask an then diluted to 60.0 cm³
3. The blue dye is then used as a titre.
4. Titration continues until the color changes from blue to colorless
5. The experiment is repeated to all the samples i.e. lemon, orange and blackcurrant.
6. The procedure 1-4 repeats for sample B.

Results

The results are recorded, compared and interpreted. The following table is used to put down data for the various samples.

This table is draw for both sample A and B

Calculation

The amount of vitamin C in a solution can be worked out by finding out how much must be added to 1 cm3 of the blue dye to turn it clear. To determine the above it is important to first find out the relationship between the blue dye and the standard ascorbic acid solution. In our case we calculate as follows:-

Assume that xcm3 is the blue dye used to 30.cm3 of a solution containing about 0.1mgcm-3 of ascorbic acid

Then x cm3 of blue dye = 4/x mg of ascorbic acid which brings to the conclusion:

1 cm3 of dye=3/x mg of ascorbic acid. This equation can then be used to estimate vitamin C in fruit juice using the following formula (Rastogi, 2005).

Mg/100 ml of test solution=T/st*2*dilution.

Where T is the titre value and St is the titre value obtained with the standard ascorbic acid solution.

Many experiments have shown that canned orange juice seems to have the highest concentration of vitamin C; fresh orange juice usually has the lowest.

Reference

Rastogi, S.C. 2005. Experimental Physiology, New Age Publishers.

The Potential Role of Vitamin D for Prevention and Treatment of Tuberculosis and Infectious Diseases

This study investigates the use of vitamin D for the deterrence and cure of tuberculosis and other contagious infections. Deficiency of vitamin D is a global problem which results in higher occurrences of the immune system ailments.

Its deficiency also augments the proliferation of communicable diseases. Vitamin D is a vital micronutrient for healthy bones and prevention (or treatment) of many chronic ailments because of its intricate activity on the immune system.

Dini and Bianchi (2012) cite that deficiency of vitamin D leads to an increased risk of developing tuberculosis (TB). This study explains the use of vitamin D as a drug before the invention of antibiotics.

The unearthing of vitamin D as a therapeutic agent begins with the detection of rickets as a childhood malady and the subsequent association of rickets to lack of exposure to sunshine.

Cod liver oil, which contains vitamin D, is then used as a cure for rickets and tuberculosis.

Studies show that vitamin D production increases in the body when special receptors (Toll-like receptors or TLR) sense the presence of the tuberculosis bacteria. This vitamin is in the form of 1, 25-dihydroxyvitamin D.

Its synthesis encourages “VDR-mediated transactivation of the antimicrobial peptide cathelicidin and killing of intracellular Mycobacterium tuberculosis” (Dini and Bianchi, 2012, p. 319).

Cathelicidin has antiviral and antibacterial results. TLR instigation also yields defensin-2, another peptide with antibiotic properties.

This study hopes to find out how cathelicidins control immune reactions. This knowledge aids the creation of complexes containing the normal chemotherapy, antimicrobial proteins, and dietary shortage rectification components. Such complexes symbolize a significant advancement in TB therapies.

Pharmaceutical Aerosols for the Treatment and Prevention of Tuberculosis

This study investigates the ability to offer TB treatment in a unique form by deviating from the traditional tablets and injections. It aims to improve the competence of TB treatment in terms of cost-effectiveness and efficiency.

Hanif and Garcia-Contreras propose the use of powdered aerosols to mitigate the hindrances posed by liquid drug formulations (2012). Pharmaceutical aerosols provide the advantage of effective drug distribution and cost effectiveness.

Tuberculosis remains a key community health hazard worldwide although it can be treated and precluded. Hanif and Garcia-Contreras cite that a significant number of people who contract the TB bacteria develop the disease and die.

Treatment of obtrusive airway ailments always involves aerosols. However, the recent inventions see this treatment extend to cure lung diseases related to cystic fibrosis. An individual acquires tuberculosis by breathing in aerosol drops containing the infectious bacteria from the infected person.

The basis of this research is that since tuberculosis mainly upsets lungs, then the lungs are a substitute means of administering TB drugs.

However, this method requires precise drug formulations and administrative procedures for effectiveness. Pharmaceutical companies can utilize numerous techniques to produce the fine particles suitable for inhalation.

An earlier therapy approach, the Directly Observed Therapy Short Course (DOTS), requires direct monitoring of TB patients as they take their medicine.

This is extremely involving as Mycobacterium tuberculosis bacilli (MTB) are among the most stubborn human pathogens due to their ability to multiply remarkably fast intracellularly and outside the living cells (2012).

This study uses small animal models to test the efficacy of the powdered aerosols and hopes to extend the same tests to bigger models. It also hopes to improve the available inhalers for the administration of large dosages essential in TB treatment.

The Value of Systematic Physical Training in the Prevention and Cure of Pulmonary Tuberculosis

This study examines the benefits of physical exercise in the mitigation and cure of tuberculosis and other chest infections. Doctors notice “long, narrow, flat-chested” people have a high risk of contracting tuberculosis and low chances of healing (Ingals, 1898, p.40).

Physical exercises improve the wellbeing of the respiratory system. According to Ingals, pathological studies show shrunken air-cells provide the most suitable environment for multiplication of the tuberculosis bacteria (1898).

He attributes this to anemia which reduces the ability of the air-cells to fight infections. Prevalence reports estimate 80% of the human populace has the Koch’s bacillus (1898).

Ingals explains that the Koch’s bacillus is not detrimental, and ample body resistance is sufficient to avoid the real illness.

This study aims at educating the public “to strengthen the resisting power of all the body tissues, but more especially those of the lungs, because they afford the most favorable conditions for the spread of the disease” (Ingals, 1898, p.41).

It suggests that large heights above the sea level offer the most excellent circumstances for preclusion of pulmonary tuberculosis. The high attitudes also aid in healing the disease in its initial phases. A patient’s attempt to take in more air expands the air cells thereby strengthening the lungs.

The study suggests that patients ought to learn how to inhale deeply and methodically inflate the lungs several times daily. Ingals further demonstrates the actual steps to follow when breathing to meet the desired effects. He asserts that continuous physical exercise may improve a narrow-chested individual’s ability to fight tuberculosis.

References

Dini, C. & Bianchi, A. (2012). The potential role of vitamin D for prevention and treatment of tuberculosis and infectious diseases. Ann Ist Super Sanita, 48(3), 319-327. Doi: 10.4415/ANN_12_03_13.

Hanif, N. M. S. and Garcia-Contrera, L. (2012). Pharmaceutical aerosols for the treatment and prevention of Tuberculosis. Frontiers in cellular and infectious microbiology,118(2) 1-11. Doi: 10.3389/fcimb.2012.00118.

Ingals, E. F. The value of systematic physical training in the prevention and cure of pulmonary tuberculosis. (1898). Transactions of the American Climatological Association, 1898(14) 40-48.

Introduction

This paper is a synopsis of the process undertaken to identify 10 articles that discuss one evidence-based practice (EBP) question, which centers on understanding whether daily Vitamin C supplements will reduce the incidence of the common cold. Generally, the target population for the review is comprised of people who are taking daily doses of Vitamin C. Comparatively, the control group is made up of people who are not taking daily doses of Vitamin C. The overriding statement of the EBP question is as described below.

A Statement of the EBP Question/Issue

Will taking daily Vitamin C supplements reduce the incidence of the common cold compared with no intervention?

Significance of the EBP Question

The common cold is a significant and recurring health problem (Douglas & Hemilä, 2005). Since it is incurable, efforts aimed at addressing the disease have been centered on managing it (Padayatty & Levine, 2016). However, the lack of extensive and in-depth scientific research studies to investigate the effectiveness of various remedies and supplements on the condition has hampered efforts to effectively manage it. The same problem has made it difficult to establish the right medication to take in treating various groups of patients (Douglas & Hemilä, 2005; Padayatty & Levine, 2016).

Based on the above issues, the findings of the EBP question will help in providing clarity regarding the efficacy of Vitamin C in reducing the symptoms of the common cold. More importantly, they will help in providing clarity regarding the extent that Vitamin C supplements could help in minimizing the symptoms of the common cold. Through the achievement of this goal, communities will be able to better manage this commonly occurring respiratory health problem and learn how to employ effective remedies to address it. Lastly, the EBP question is significant in increasing the volume of literature surrounding the multiple uses of Vitamin C. Particularly, it will be instrumental in explaining the relationship between Vitamin C and the common cold, as a specific area of respiratory health studies. The goals of the paper are as described below.

The Goals of the Paper

1. To determine whether the intake of Vitamin C contributes to a reduction in common cold symptoms
2. To investigate the extent that Vitamin C supplements decrease the incidence of the common cold

Explanation of the Search Process for the Articles

To identify articles that would help in meeting the two goals described above, a search process was undertaken to identify existing literature underpinning the research topic. Ten articles were obtained in the process and were authored by Chambial, Dwivedi, Shukla, John, and Sharma (2013), Elste, Troesch, Eggersdorfer, and Weber (2017), Garaiova et al. (2015), Hemilä (1994), Hemilä (1999), Hemilä (2013), Johnston, Barkyoumb, and Schumacher (2014), Michels and Frei (2013), Schorah (1997), Sasazuki, Sasaki, Tsubono, Okubo, Hayashi, and Tsugane (2006). The search terms used to identify the articles are described below.

Search Terms Used

Two search terms were used in undertaking the review: “Vitamin C” and “Common Cold.”

Databases Searched

Two databases were searched: “Google Scholar” and “The National Center for Biotechnology Information.”

Summary

This paper shows that the EBP question selected for review is centered on understanding whether daily Vitamin C supplements will reduce the incidence of the common cold. The process of searching for research articles was undertaken by using two phrases: “Vitamin C” and “Common Cold” in the “The National Center for Biotechnology Information” and “Google Scholar” databases. Ten articles emerged from the process. In subsequent research, they will be analyzed and compared relative to the goal of establishing whether Vitamin C reduces the symptoms of common cold, or not.

References

Chambial, S., Dwivedi, S., Shukla, K.K., John, P.J., & Sharma, P. (2013). Vitamin C in disease prevention and cure: An overview. Indian Journal of Clinical Biochemistry, 28(4), 314-328.

Douglas, R.M., & Hemilä, H. (2005). Vitamin C for preventing and treating the common cold. PLoS Med, 2(6), 503-504.

Elste, V., Troesch, B., Eggersdorfer, M., & Weber, P. (2017). Emerging evidence on neutrophil motility supporting its usefulness to define vitamin C intake requirements. Nutrients, 9(5), 503.

Garaiova, I., Muchová, J., Nagyová, Z., Wang, D., Li, J.V., Országhová, Z., …Ďuračková, Z. (2015). Probiotics and vitamin C for the prevention of respiratory tract infections in children attending preschool: A randomized controlled pilot study. European Journal of Clinical Nutrition, 69(3), 373-379.

Hemilä, H. (1994). Does vitamin C alleviate the symptoms of the common cold? A review of current evidence. Scandinavian Journal of Infectious Diseases, 26, 1-6.

Hemilä, H. (1999). Vitamin C supplementation and common cold symptoms: Factors affecting the magnitude of the benefit. Medical Hypotheses, 52(2), 171-178.

Hemilä, H. (2013). Vitamin C and common cold-induced asthma: A systematic review and statistical analysis. Allergy, Asthma, and Clinical Immunology: Official Journal of the Canadian Society of Allergy and Clinical Immunology, 9(1), 46.

Johnston, C.S., Barkyoumb, G.M., & Schumacher, S.S. (2014). Vitamin C supplementation slightly improves physical activity levels and reduces cold incidence in men with marginal vitamin C status: A randomized controlled trial. Nutrients, 6(7), 2572-2583.

Michels, A.J., & Frei, B. (2013). Myths, artifacts, and fatal flaws: Identifying limitations and opportunities in vitamin C research. Nutrients, 5(12), 5161-5192.

Padayatty, S.J., & Levine, M. (2016). Vitamin C physiology: The known and the unknown and Goldilocks. Oral Diseases, 22(6), 463-493.

Sasazuki, S., Sasaki, S., Tsubono, Y., Okubo, S., Hayashi, M., & Tsugane, S. (2006). Effect of vitamin C on common cold: Randomized controlled trial, European Journal of Clinical Nutrition, 60, 9-17.

Schorah, C.J. (1997). Vitamin C intake and susceptibility to the common cold – Invited commentaries. The British Journal of Nutrition, 78(5), 859-61.