Abnormal Vitamin Levels - A Busy Day in the Hospital
By: Team 8, PATH3500, Western University
Let's go!
Learning Objectives
By the end of this module, students should be able to:
- Understand that nutritional disorders can result from either a deficiency (primary or secondary) or an excess of nutrients.
- Understand the differences between water-soluble and fat-soluble vitamins.
- Evaluate the distinct functions, deficiencies, and toxicities of the 5 selected vitamins (A, B9, B12, C, D).
- Apply knowledge of the different nutritional disorders and vitamins to realistic situations by evaluating a hypothetical patient profile to discern a diagnosis.
Start Module
Index
Vitamin A
Introduction to Vitamins
Vitamin B12
Vitamin D
Vitamin C
Vitamin B9
References
Test Your Knowledge
Introduction to Vitamins
Vitamins are micronutrients that, despite making up a relatively small portion of our diet, help maintain the body’s functions. While vitamins are an important part of our diet, not all of the vitamin content in foods is available for the body to use. The concept, known as bioavailability, refers to the amount of a nutrient absorbed and effectively utilized by the body4.
Introduction to Vitamins
Factors Affecting Bioavailability
Bioavailability can vary depending on several factors:
Food Preparation and Cooking
Medications
Genetics
Introduction to Vitamins
Solubility of Vitamins
Created with BioRender.com.
The solubility of a vitamin determines how it is absorbed, transported, and stored in the body4.
Water-Soluble Vitamins
Created with BioRender.com.
Fat-Soluble Vitamins
Introduction to Vitamins
Vitamin Deficiencies
Secondary Deficiency
Primary Deficiency
Vitamin A
10
VITAMIN A
Vitamin A
Roles of Vitamin A
Cell Growth & Differentiation
Lipid Metabolism
Vision
Immunity
Vitamin A
Plant Sources of Vitamin A
Animal Sources of Vitamin A
14
15
17
- Carrots, squash, spinach, sweet potatoes, and bell peppers 12,13
16
- Fish, dairy, eggs, and liver 12,13
- Retinol (preformed vitamin A) 11
- Provitamin A (carotenoids converted into active vitamin A in the body) 11
Vitamin A
Vitamin A Deficiency
Causes of Deficiency:
- Inadequate dietary intake (common in malnourished populations) 11
- Fat malabsorption disorders (such as Crohn’s disease or celiac disease) 11
- Liver disease, which can impair vitamin A storage 11
Clinical Manifestations:
Visual Impairments
Skin and Mucous Changes
- Dry, rough, and scaly skin due to keratinization 12, 13
- Increased risk of infections due to a breakdown of protective barriers 19
Created with BioRender.com.
Immune Function
Info
- Higher likelihood of respiratory and gastrointestinal infections 19
Vitamin A
Vitamin A Toxicity
- Since vitamin A is fat-soluble, it is stored in the liver and fatty tissues, making excessive intake a risk 20
Acute Toxcity
Chronic Toxcity
- Results from a single high dose, with symptoms including 12, 13 :
- Results from prolonged excessive intake, with symptoms including: 12, 13, 20
Created with BioRender.com.
Created with BioRender.com.
Created with BioRender.com.
Vitamin B12
21
VITAMIN B12
Vitamin B12
Roles of Vitamin B12
Neurological Function12
Red Blood Cell Formation12
DNA Synthesis12
Vitamin B12
12
Foods Rich In Vitamin B12
22
24
26
Eggs
Nuts
Fish
Dairy Products
Red Meat
25
23
Vitamin B12
Vitamin B12 Deficiency: Causes
27
28
Secondary: Impaired Absorption
Primary: Decreased Intake
...Even if you later explain it orally
Sometimes, a deficiency of vitamin B12 can be caused by inadequate dietary intake12.
Upon ingestion, vitamin B12 enters a complex intrinsic process as it travels through the digestive tract and is absorbed. Faults in any step of this process can cause B12 deficiency12.
+ info
+ info
Vitamin B12
Impaired Absorption: Possible Pathogenesis
32
Pernicious Anemia
Intrinsic Factor Deficiency
An autoimmune condition that causes gastric atrophy, a decrease in IF levels, and achlorhydria (failed production of hydrochloric acid within the stomach)33.
IF is a crucial component in facilitating B12 uptake. A decrease in its levels or function can have drastic effects12.
Malabsorption States
34
35
37
31
36
Gastrectomy
12
Medications for Acid Reflux
12
Diffuse Intestinal Disease
Alcoholism
Ileal Resection or Ileitis
12
12
12
Vitamin B12
Clinical Manifestations
Atrophy and Ulceration of Oral Mucosa12
Neurological Impairment
Anemia
- Low red blood cell count12
- Macrocytic red blood cells12
- Degeneration of the spinal cord due to defected myelin formation12
38
Vitamin B12
Vitamin B12 Toxicity
This is a water-soluble vitamin, so toxicity is unlikely and not a major concern12.
39
40
Rarely, those receiving B12 injections can exhibit the side effects of a large dose, these symptoms being nausea, vomiting, or pain at the injection site41.
Vitamin C
42
VITAMIN C
Vitamin C
Roles of Vitamin C
Antioxidant Properties
Connective Tissue Formation
Iron Uptake
Vitamin C
Sources of Vitamin C
Fruits43
Vegetables43
Vitamin C
54
Vitamin C Deficiency - Scurvy
Risk Factors:
- Eating disorders55
- Lack of fruits/vegetables in diet55
- Smoking55
- Long-term alcohol or drug use55
- Age55
- Dialysis55
Characterized by defective collagen synthesis & defective osteoid synthesis13. Deficient vitamin C suppresses collagen peptide synthesis leading to a lack of tensile strength & increased vulnerability to enzymatic degradation of connective tissue13.
+ info
Since Vitamin C is not produced endogenously in humans, the risk of deficiency is even greater as it is entirely diet dependent13.
Vitamin C
Clinical Signs & Symptoms
Patients with scurvy can present with the following signs and symptoms depending on severity:
Tooth Loss
Pale Skin
Sunken Eyes
Under eye hollows due to impaired collagen synthesis causing the eyes to appear sunken13.
Due to reduced iron absorption, iron deficiency anemia can occur13.
Tooth loss and decay due to impaired dentin and collagen formation13.
Petechiae
Gingivitis & Ulceration of Gums
Stiff & Swollen Joints
Small red or purple spots on the skin due to impaired collagen synthesis causing fragile blood vessels43.
Gum bleeding and inflammation due to defective collagen formation43.
Joint pain due to defective osteoid and collagen formation43.
Vitamin C
57
Vitamin C Toxicity
56
While rare due to urinary excretion of vitamin C, amounts greater than 2,000 mg/day can lead to vitamin C toxicity44. Vitamin C toxicity is characterized by an upset stomach, diarrhea, and in severe cases, kidney stones44.
58
Vitamin D
VITAMIN D
Vitamin D
Overview
Vitamin D is derived from cholesterol. D2 (ergocalciferol) and D3 (calcitriol) are the only forms with known biological effects in the human body. The skin can synthesize vitamin D when exposed to sunlight4.
Vitamin D
When Calcium Levels are Low:
Role of Vitamin D
Calcium Homeostasis
The active form of vitamin D (calcitriol) enhances the absorption of calcium and phosphorus in the intestine4.
Created with BioRender.com.
Vitamin D
Sources of Vitamin D
Sunlight
Diet
Most individuals require between 5 to 30 minutes of sun exposure between 10 AM and 4 PM, at least twice a week, to produce sufficient vitamin D4.
A limited number of foods are naturally rich in vitamin D, such as fatty fish (e.g., salmon, tuna, and mackerel), cod liver oil, egg yolks, and cheese4.
Several factors can reduce sunlight exposure, hindering vitamin D synthesis, including:
59
60
61
62
Vitamin D
Vitamin D Deficiency
Vitamin D deficiency is the most common cause of rickets and osteomalacia63.
Rickets
Osteomalacia
64
Created with BioRender.com.
These conditions are closely linked, as children with rickets often develop osteomalacia63.
Vitamin D
Vitamin D Toxicity
Vitamin D toxicity typically results from taking too much prescription-strength vitamin D or excessive over-the-counter supplements65. Vitamin D toxicity leads to hypercalcemia (elevated calcium levels in the blood), causing symptoms such as decreased appetite, nausea, vomiting, constipation, dehydration, polydipsia (increased thirst), frequent urination, bone pain, and kidney stones65. Severe cases of toxicity can result in kidney failure, arrhythmia (irregular heart rhythm), ataxia (unsteady gait), and confusion65.
Created with BioRender.com.
70
Vitamin B9
VITAMIN B9
Vitamin B9
Roles of Vitamin B9
Neural Tube Formation
DNA Synthesis & Cell Division
Key coenzyme in nucleic acid synthesis. Helps with DNA replication and repair, cell division, red blood cell production, and tissue repair ⁶⁶.
Supports neural tube formation, reducing birth defect risks in pregnancy⁶⁷.
Amino Acid Metabolism
Red Blood Cell Formation
Converts homocysteine to methionine, aiding protein synthesis and cardiovascular health⁶⁷.
Supports erythropoiesis and, with vitamin B12, prevents megaloblastic anemia⁶⁶.
Vitamin B9
Hover over each for an example!
Sources of Vitamin B9
71
72
73
Citrus Fruits68
Legumes68
Leafy Greens68
Next
74
76
75
Nuts & Seeds68
Animal Sources68
Fortified Grains68
Vitamin B9
77
Deficiency & Megaloblastic Anemia
Folate is crucial for red blood cell (RBC) production. Its deficiency impairs DNA synthesis, causing abnormally large and immature RBCs (megaloblasts), leading to megaloblastic anemia⁶⁷.
Symptoms
69
At-Risk Groups
66
Vitamin B9
Deficiency & Neural Tube Defects
A vitamin B9 deficiency during early pregnancy can cause neural tube defects (NTDs), i.e. severe congenital abnormalities of the brain and spinal cord due to improper neural tube closure within the first 28 days⁶⁷.
Common NTDs
67
78
Tap the arrow to unveil the condition name!
Encephalocele
Spina Bifida
Anencephaly
Vitamin B9
Consequences of Excess Vitamin B9
79
Masked B12 Deficiency
Neurological Effects
68
Cancer Risk
68
68
+ info
+ info
+ info
Test Your Knowledge
Now that you've mastered the material, it's time to put that knowledge to use! Are you able to diagnose vitamin deficiencies and toxicities in clinical cases?
Test Your Knowledge
Patient Information
Name: Maria Pedro Age: 41 Sex: Female Medical History: History of alcohol use disorder, mild liver steatosis Diet: Irrregular meals, relies heavily on processed food and rice; low in fresh produce.
Presenting Complaints:
- Increasing fatigue over the past few months
- Frequent forgetfulness and difficulty with focus
- Tingling in hands and feet
- Episodes of lightheadedness
- Recent irritability and depressed mood
Case and image generated by AI.
Notes: Labs show normal serum B12, and elevated MCV (red blood cells larger than normal).
Test Your Knowledge
Patient InformationName: Emma Carter Age: 30 Sex: Female Medical History: No chronic illnesses or medications. Diet: Vegan without fortified foods and supplements. Lifestyle: Works from home and mostly remains indoors due to busy work schedule.
Presenting Complaints:
- Bone pain
- Muscle weakness
- Fractured hip by slipping in the bathtub
Case and image generated by AI.
Test Your Knowledge
Patient Information
Name: Linda Morrison Age: 52 Sex: Female Medical History: History of autoimmune disorders (Hashimoto's thyroiditis), chronic gastritis Diet: Balanced omnivorous diet, no recent dietary changes.
Presenting Complaints:
- Persistent fatigue and shortness of breat on exertion
- Mild jaundice noted by her primary doctor
- Sore, swollen tongue with a striped red pattern
- Occasional heart palpitations
Case and image generated by AI.
Vital Signs: HR: 102 bmp. BP: 118/76.
Test Your Knowledge
Patient InformationName: James Portis Age: 65 Sex: Male Medical History: Type 2 Diabetes, Mild Osteoarthritis Diet: Limited due to poor dentition, avoids fruits & vegetables; mainly consumes tea, toast & processed meats Lifestyle: Lives alone in a low-income housing unit, limited mobility & minimal social support
Presenting Complaints:
- Bleeding Gums
- Joint Pain
- Fatigue
- Easy Bruising
Case and image generated by AI.
Clinical Notes:
- On physical exam: swollen, spongy gums, perifollciluar hemorrhages on legs
- Blood Work: Low plasma ascorbic acid levels
Test Your Knowledge
Patient Information
Name: Leila Rahman Age: 7 Sex: Female Medical History: No significant past medical history. Diet: Primarily rice and lentils, with very little intake of leafy vegetables or animal products.
Presenting Complaints:
- Leila has been unusually clumsy in the evenings, often tripping over objects at home.
On physical examination:
- Skin: Dry, scaly patches on the forearms and generalized rough skin texture.
- Eyes: Slight dryness observed; a faint, foamy patch is visible on the lateral conjunctiva of the right eye.
Case and image generated by AI.
Test Your Knowledge
Patient InformationName: Sarah Lockwood Age: 34 Sex: Female Medical History: History of anxiety, no chronic illnesses Diet: Vegetarian with high intake of fruits & supplements Lifestyle: Health-conscious, exercises regularly, takes large doses of vitamin supplements (~2,000 mg/day of vitamin C for "immune boosting"
Presenting Complaints:
- Nausea
- Abdominal Cramps
- Frequent urination
Case and image generated by AI.
Clinical Notes:
- No physical abnormalities on exam
- Blood work: normal renal function; elevated oxalate in urine
Test Your Knowledge
Patient InformationName: Mark Thompson Age: 50 Sex: Male Medical History: No history of bone disorders. Diet: Takes a multivitamin containing 5000 IU of vitamin D daily. Lifestyle: Lives in a sunny region and spends a lot of time outdoors.
Presenting Complaints:
- Excessive thirst and frequent urination
Case and image generated by AI.
Test Your Knowledge
Patient Information
Name: Karen Nelson Age: 34 Sex: Female Medical History: Celiac disease and non-alcoholic fatty liver disease (NAFLD). Diet: Gluten-free and dairy-free
Presenting Complaints:
- Night vision difficulties
- Dry, scaly skin
- Bone pain in hips and back
- Muscle weakness (struggles to stand from chair)
- Tenderness of bone
Case and image generated by AI.
Test Your Knowledge
Patient Information
Name: Rajiv Patel Age: 68 Sex: Male Medical History: Type 2 Diabetes (on metformin), hypertension, long-standing vegetarian Diet: Strict vegetarian diet over 40 years, minimal dairy intake
Presenting Complaints:
- Progressive fatigue over the past few months
- Numbness and tingling in hands and feet
- Difficulty with balance when walking
- Occasional memory lapses and irritability
- Pale complexion noted by family
Case and image generated by AI.
Test Your Knowledge
Patient Information
Name: Fatima Noor Age: 32 Sex: Female Medical History: No significant medical history, 24 weeks pregnant Diet: Minimal leafy greens, no prenatal supplements
Presenting Complaints:
- Increasing fatigue over past couple weeks
- Ocassional palpitations
- Pale skin
- Fetal growth is slightly below gestational age at last ultrasound.
Case and image generated by AI.
References
References
Please scan the QR code below.
You have reached the end of this module!
Congratulations!
Enhancing Immunity
Vitamin A supports the body’s immune defenses by maintaining the integrity of the skin and mucous membranes, which act as barriers against pathogens 11.
- It also plays a role in the activation and function of T-cells, which help fight infections11.
Antioxidant Properties
Vitamin C is an antioxidant that helps protect your cells against free radicals. Free radicals include molecules produced when your body breaks down food, is exposed to radiation, smoke or X-rays. Free radicals increase oxidative stress placed on cells, leading to a variety of adverse effects43.
Maintaining Healthy Vision
Vitamin A mediates normal vision and is essential for the production of rhodopsin, a light-sensitive pigment found in the rod cells of the retina that enables vision in dim or low-light conditions 11.
- This process requires the conversion of retinol → retinal → rhodopsin 12,13
- Additionally, Vitamin A helps maintain the health of the cornea, keeping the eye’s outer surface moist and supporting overall clarity and function 11.
13
Impaired Absorption
Mechanism of B12 Absorption:
- B12 is ingested and travels to the stomach, where it forms a complex with pepsin (secreted by gastric parietal cells)12.
- This complex exits the stomach and enters the duodenum, where B12 detaches from pepsin and binds to haptocorrin12.
- Proteases secreted by the pancreas split this complex as it travels further down, allowing for B12 binding with the intrinsic factor (IF)12.
- In this form, the IF-B12 complex circulates to the ileum, where it attaches to an IF receptor on ileal cells12.
- B12 is subsequently released and becomes available for cellular functions12.
Water-Soluble Vitamins
Vitamins B and C are absorbed into the bloodstream through the capillaries in the villi of the small intestine. From there, they are carried to the liver. Water-soluble vitamins are not stored in the body. When consumed in excess, the kidneys filter out the surplus, which is then excreted through urine. Because of this, they need to be consumed regularly to prevent deficiency. Toxicity is rare due to the body’s ability to excrete these amounts4.
Geographic Latitude
Sunlight exposure is highest at the equator and decreases as you move farther north or south4.
Regulating Lipid Metabolism
Vitamin A is involved in lipid metabolism, helping to regulate the storage and use of fats in the body11.
- It also reduces oxidative stress by stabilizing lysosomes, which are responsible for cellular waste breakdown and recycling 12,13.
Medications
Certain medications may interfere with the absorption or metabolism of specific vitamins4.
Vitamin D works with the parathyroid hormone (PTH) to reduce calcium loss through urine by enhancing its absorption in the kidneys and stimulating the release of calcium and phosphorus from bones4.
Skin Pigmentation
Darker skin, due to higher melanin levels, reduces the skin’s ability to absorb sunlight4.
Fat-Soluble Vitamins
Vitamins A, D, E, and K are absorbed into the lacteal within the villi of the small intestine. From there, they travel through the lymphatic system to the liver. Fat-soluble vitamins are absorbed alongside dietary fat, therefore, a low-fat meal can impair absorption. Fat-soluble vitamins are stored in visceral and subcutaneous fat, which makes it harder for deficiencies to develop. However, excessive intake of these vitamins can lead to toxicity as they accumulate in the body’s fat stores4.
Developed B12 Deficiency
Early B12 Deficiency
12
12
- Red tongue with lighter stripes
(can also present in vitamin B9 deficiency)
Primary Deficiency
An individual does not consume enough of a specific vitamin4.
Inadequate Intake
29
This type of deficiency is typically only seen in:
- Vegetarians12
- Elderly12
- Alcoholics12
30
31
Secondary Deficiency
Arises from an underlying condition that limits the absorption or utilization of the vitamin. Lifestyle factors (e.g., smoking and alcohol use), medications, or other health conditions may influence these processes4.
Iron Uptake
Vitamin C enhances absorption of non-heme iron by converting it to a more readily absorbable form. In fact, Vitamin C is the only dietary supplement other than animal tissue that has been found to promote iron absorption43.
Visual Impairments
- Night Blindness: Difficulty seeing in low light 12,13,18
- Vitamin A defciency causes squamous metaplasia of epithelial cells, leading to:
- Xerophthalmia: Severe dryness of the eye leading to Bitot’s spots, which are foamy patches on the conjunctiva12,13,18
- Keratomalacia: Softening and breakdown of the cornea, which can result in total blindness if untreated 12,13, 18
- Corneal ulcer: also known as keratitis, open sore on cornea 12,13
Created with BioRender.com.
Ozone and Air Pollution
Both block sunlight4.
Connective Tissue Formation
Vitamin C is key for the formation of intercellular ground substances of bone, dentin and other connective tissues such as blood vessels. Vitamin C is a co-factor in the activation of proline/lysine hydrolases that allow the cross-linking of proline and lysine residues in collagen44.
13
History of Scurvy
British sailors in the 19th century were called "limeys" because their tendency to consume citrus fruits (lemons, limes & oranges) to avoid scurvy on long voyages. However, today's cases are typically due to secondary causes such as old age and chronic alcohol use13.
Histologically seen as megaloblastic anemia
13
Did you know?
Vitamin C is the only essential vitamin not in high amounts in cooked animal foods! Only raw liver, fish roe, and eggs are known to contain sufficient amounts of Vitamin C53.
Genetics
Genetic variations can enhance or limit the body’s ability to absorb and utilize vitamins4.
Food Preparation and Cooking
Water-soluble vitamins are sensitive to destruction when boiled, over-cooked, or exposed to excessive light4.
Regulating Cell Growth + Differentiation
Vitamin A is essential for the normal differentiation of epithelial cells, which form protective linings in areas like the respiratory and digestive tracts 11, 12, 13.
- It is specifically required for the differentiation of mucus-secreting epithelium, helping to maintain cells that keep tissues moist, functional, and protected 12,13
- Deficiency can lead to abnormal keratinization (squamous metaplasia), where epithelial cells harden and lose their normal function11,12,13
Abnormal Vitamin Levels - A Busy Day in the Hospital
PATH3500 Team 8
Created on March 22, 2025
Many health problems begin with something simple: not getting the right nutrients. While often overlooked, vitamin imbalances can affect everything from how we see at night to how our bones grow and heal.
Start designing with a free template
Discover more than 1500 professional designs like these:
View
Neodigital CPD Course
View
Minimal Course
View
Basic Interactive Course
View
Laws and Regulations Course
Explore all templates
Transcript
Abnormal Vitamin Levels - A Busy Day in the Hospital
By: Team 8, PATH3500, Western University
Let's go!
Learning Objectives
By the end of this module, students should be able to:
Start Module
Index
Vitamin A
Introduction to Vitamins
Vitamin B12
Vitamin D
Vitamin C
Vitamin B9
References
Test Your Knowledge
Introduction to Vitamins
Vitamins are micronutrients that, despite making up a relatively small portion of our diet, help maintain the body’s functions. While vitamins are an important part of our diet, not all of the vitamin content in foods is available for the body to use. The concept, known as bioavailability, refers to the amount of a nutrient absorbed and effectively utilized by the body4.
Introduction to Vitamins
Factors Affecting Bioavailability
Bioavailability can vary depending on several factors:
Food Preparation and Cooking
Medications
Genetics
Introduction to Vitamins
Solubility of Vitamins
Created with BioRender.com.
The solubility of a vitamin determines how it is absorbed, transported, and stored in the body4.
Water-Soluble Vitamins
Created with BioRender.com.
Fat-Soluble Vitamins
Introduction to Vitamins
Vitamin Deficiencies
Secondary Deficiency
Primary Deficiency
Vitamin A
10
VITAMIN A
Vitamin A
Roles of Vitamin A
Cell Growth & Differentiation
Lipid Metabolism
Vision
Immunity
Vitamin A
Plant Sources of Vitamin A
Animal Sources of Vitamin A
14
15
17
16
Vitamin A
Vitamin A Deficiency
Causes of Deficiency:
Clinical Manifestations:
Visual Impairments
Skin and Mucous Changes
Created with BioRender.com.
Immune Function
Info
Vitamin A
Vitamin A Toxicity
Acute Toxcity
Chronic Toxcity
Created with BioRender.com.
Created with BioRender.com.
Created with BioRender.com.
Vitamin B12
21
VITAMIN B12
Vitamin B12
Roles of Vitamin B12
Neurological Function12
Red Blood Cell Formation12
DNA Synthesis12
Vitamin B12
12
Foods Rich In Vitamin B12
22
24
26
Eggs
Nuts
Fish
Dairy Products
Red Meat
25
23
Vitamin B12
Vitamin B12 Deficiency: Causes
27
28
Secondary: Impaired Absorption
Primary: Decreased Intake
...Even if you later explain it orally
Sometimes, a deficiency of vitamin B12 can be caused by inadequate dietary intake12.
Upon ingestion, vitamin B12 enters a complex intrinsic process as it travels through the digestive tract and is absorbed. Faults in any step of this process can cause B12 deficiency12.
+ info
+ info
Vitamin B12
Impaired Absorption: Possible Pathogenesis
32
Pernicious Anemia
Intrinsic Factor Deficiency
An autoimmune condition that causes gastric atrophy, a decrease in IF levels, and achlorhydria (failed production of hydrochloric acid within the stomach)33.
IF is a crucial component in facilitating B12 uptake. A decrease in its levels or function can have drastic effects12.
Malabsorption States
34
35
37
31
36
Gastrectomy
12
Medications for Acid Reflux
12
Diffuse Intestinal Disease
Alcoholism
Ileal Resection or Ileitis
12
12
12
Vitamin B12
Clinical Manifestations
Atrophy and Ulceration of Oral Mucosa12
Neurological Impairment
Anemia
38
Vitamin B12
Vitamin B12 Toxicity
This is a water-soluble vitamin, so toxicity is unlikely and not a major concern12.
39
40
Rarely, those receiving B12 injections can exhibit the side effects of a large dose, these symptoms being nausea, vomiting, or pain at the injection site41.
Vitamin C
42
VITAMIN C
Vitamin C
Roles of Vitamin C
Antioxidant Properties
Connective Tissue Formation
Iron Uptake
Vitamin C
Sources of Vitamin C
Fruits43
Vegetables43
Vitamin C
54
Vitamin C Deficiency - Scurvy
Risk Factors:
Characterized by defective collagen synthesis & defective osteoid synthesis13. Deficient vitamin C suppresses collagen peptide synthesis leading to a lack of tensile strength & increased vulnerability to enzymatic degradation of connective tissue13.
+ info
Since Vitamin C is not produced endogenously in humans, the risk of deficiency is even greater as it is entirely diet dependent13.
Vitamin C
Clinical Signs & Symptoms
Patients with scurvy can present with the following signs and symptoms depending on severity:
Tooth Loss
Pale Skin
Sunken Eyes
Under eye hollows due to impaired collagen synthesis causing the eyes to appear sunken13.
Due to reduced iron absorption, iron deficiency anemia can occur13.
Tooth loss and decay due to impaired dentin and collagen formation13.
Petechiae
Gingivitis & Ulceration of Gums
Stiff & Swollen Joints
Small red or purple spots on the skin due to impaired collagen synthesis causing fragile blood vessels43.
Gum bleeding and inflammation due to defective collagen formation43.
Joint pain due to defective osteoid and collagen formation43.
Vitamin C
57
Vitamin C Toxicity
56
While rare due to urinary excretion of vitamin C, amounts greater than 2,000 mg/day can lead to vitamin C toxicity44. Vitamin C toxicity is characterized by an upset stomach, diarrhea, and in severe cases, kidney stones44.
58
Vitamin D
VITAMIN D
Vitamin D
Overview
Vitamin D is derived from cholesterol. D2 (ergocalciferol) and D3 (calcitriol) are the only forms with known biological effects in the human body. The skin can synthesize vitamin D when exposed to sunlight4.
Vitamin D
When Calcium Levels are Low:
Role of Vitamin D
Calcium Homeostasis
The active form of vitamin D (calcitriol) enhances the absorption of calcium and phosphorus in the intestine4.
Created with BioRender.com.
Vitamin D
Sources of Vitamin D
Sunlight
Diet
Most individuals require between 5 to 30 minutes of sun exposure between 10 AM and 4 PM, at least twice a week, to produce sufficient vitamin D4.
A limited number of foods are naturally rich in vitamin D, such as fatty fish (e.g., salmon, tuna, and mackerel), cod liver oil, egg yolks, and cheese4.
Several factors can reduce sunlight exposure, hindering vitamin D synthesis, including:
59
60
61
62
Vitamin D
Vitamin D Deficiency
Vitamin D deficiency is the most common cause of rickets and osteomalacia63.
Rickets
Osteomalacia
64
Created with BioRender.com.
These conditions are closely linked, as children with rickets often develop osteomalacia63.
Vitamin D
Vitamin D Toxicity
Vitamin D toxicity typically results from taking too much prescription-strength vitamin D or excessive over-the-counter supplements65. Vitamin D toxicity leads to hypercalcemia (elevated calcium levels in the blood), causing symptoms such as decreased appetite, nausea, vomiting, constipation, dehydration, polydipsia (increased thirst), frequent urination, bone pain, and kidney stones65. Severe cases of toxicity can result in kidney failure, arrhythmia (irregular heart rhythm), ataxia (unsteady gait), and confusion65.
Created with BioRender.com.
70
Vitamin B9
VITAMIN B9
Vitamin B9
Roles of Vitamin B9
Neural Tube Formation
DNA Synthesis & Cell Division
Key coenzyme in nucleic acid synthesis. Helps with DNA replication and repair, cell division, red blood cell production, and tissue repair ⁶⁶.
Supports neural tube formation, reducing birth defect risks in pregnancy⁶⁷.
Amino Acid Metabolism
Red Blood Cell Formation
Converts homocysteine to methionine, aiding protein synthesis and cardiovascular health⁶⁷.
Supports erythropoiesis and, with vitamin B12, prevents megaloblastic anemia⁶⁶.
Vitamin B9
Hover over each for an example!
Sources of Vitamin B9
71
72
73
Citrus Fruits68
Legumes68
Leafy Greens68
Next
74
76
75
Nuts & Seeds68
Animal Sources68
Fortified Grains68
Vitamin B9
77
Deficiency & Megaloblastic Anemia
Folate is crucial for red blood cell (RBC) production. Its deficiency impairs DNA synthesis, causing abnormally large and immature RBCs (megaloblasts), leading to megaloblastic anemia⁶⁷.
Symptoms
69
At-Risk Groups
66
Vitamin B9
Deficiency & Neural Tube Defects
A vitamin B9 deficiency during early pregnancy can cause neural tube defects (NTDs), i.e. severe congenital abnormalities of the brain and spinal cord due to improper neural tube closure within the first 28 days⁶⁷.
Common NTDs
67
78
Tap the arrow to unveil the condition name!
Encephalocele
Spina Bifida
Anencephaly
Vitamin B9
Consequences of Excess Vitamin B9
79
Masked B12 Deficiency
Neurological Effects
68
Cancer Risk
68
68
+ info
+ info
+ info
Test Your Knowledge
Now that you've mastered the material, it's time to put that knowledge to use! Are you able to diagnose vitamin deficiencies and toxicities in clinical cases?
Test Your Knowledge
Patient Information
Name: Maria Pedro Age: 41 Sex: Female Medical History: History of alcohol use disorder, mild liver steatosis Diet: Irrregular meals, relies heavily on processed food and rice; low in fresh produce.
Presenting Complaints:
Case and image generated by AI.
Notes: Labs show normal serum B12, and elevated MCV (red blood cells larger than normal).
Test Your Knowledge
Patient InformationName: Emma Carter Age: 30 Sex: Female Medical History: No chronic illnesses or medications. Diet: Vegan without fortified foods and supplements. Lifestyle: Works from home and mostly remains indoors due to busy work schedule.
Presenting Complaints:
Case and image generated by AI.
Test Your Knowledge
Patient Information
Name: Linda Morrison Age: 52 Sex: Female Medical History: History of autoimmune disorders (Hashimoto's thyroiditis), chronic gastritis Diet: Balanced omnivorous diet, no recent dietary changes.
Presenting Complaints:
Case and image generated by AI.
Vital Signs: HR: 102 bmp. BP: 118/76.
Test Your Knowledge
Patient InformationName: James Portis Age: 65 Sex: Male Medical History: Type 2 Diabetes, Mild Osteoarthritis Diet: Limited due to poor dentition, avoids fruits & vegetables; mainly consumes tea, toast & processed meats Lifestyle: Lives alone in a low-income housing unit, limited mobility & minimal social support
Presenting Complaints:
Case and image generated by AI.
Clinical Notes:
Test Your Knowledge
Patient Information
Name: Leila Rahman Age: 7 Sex: Female Medical History: No significant past medical history. Diet: Primarily rice and lentils, with very little intake of leafy vegetables or animal products.
Presenting Complaints:
- Leila has been unusually clumsy in the evenings, often tripping over objects at home.
On physical examination:Case and image generated by AI.
Test Your Knowledge
Patient InformationName: Sarah Lockwood Age: 34 Sex: Female Medical History: History of anxiety, no chronic illnesses Diet: Vegetarian with high intake of fruits & supplements Lifestyle: Health-conscious, exercises regularly, takes large doses of vitamin supplements (~2,000 mg/day of vitamin C for "immune boosting"
Presenting Complaints:
Case and image generated by AI.
Clinical Notes:
Test Your Knowledge
Patient InformationName: Mark Thompson Age: 50 Sex: Male Medical History: No history of bone disorders. Diet: Takes a multivitamin containing 5000 IU of vitamin D daily. Lifestyle: Lives in a sunny region and spends a lot of time outdoors.
Presenting Complaints:
Case and image generated by AI.
Test Your Knowledge
Patient Information
Name: Karen Nelson Age: 34 Sex: Female Medical History: Celiac disease and non-alcoholic fatty liver disease (NAFLD). Diet: Gluten-free and dairy-free
Presenting Complaints:
Case and image generated by AI.
Test Your Knowledge
Patient Information
Name: Rajiv Patel Age: 68 Sex: Male Medical History: Type 2 Diabetes (on metformin), hypertension, long-standing vegetarian Diet: Strict vegetarian diet over 40 years, minimal dairy intake
Presenting Complaints:
Case and image generated by AI.
Test Your Knowledge
Patient Information
Name: Fatima Noor Age: 32 Sex: Female Medical History: No significant medical history, 24 weeks pregnant Diet: Minimal leafy greens, no prenatal supplements
Presenting Complaints:
Case and image generated by AI.
References
References
Please scan the QR code below.
You have reached the end of this module!
Congratulations!
Enhancing Immunity
Vitamin A supports the body’s immune defenses by maintaining the integrity of the skin and mucous membranes, which act as barriers against pathogens 11.
Antioxidant Properties
Vitamin C is an antioxidant that helps protect your cells against free radicals. Free radicals include molecules produced when your body breaks down food, is exposed to radiation, smoke or X-rays. Free radicals increase oxidative stress placed on cells, leading to a variety of adverse effects43.
Maintaining Healthy Vision
Vitamin A mediates normal vision and is essential for the production of rhodopsin, a light-sensitive pigment found in the rod cells of the retina that enables vision in dim or low-light conditions 11.
13
Impaired Absorption
Mechanism of B12 Absorption:
Water-Soluble Vitamins
Vitamins B and C are absorbed into the bloodstream through the capillaries in the villi of the small intestine. From there, they are carried to the liver. Water-soluble vitamins are not stored in the body. When consumed in excess, the kidneys filter out the surplus, which is then excreted through urine. Because of this, they need to be consumed regularly to prevent deficiency. Toxicity is rare due to the body’s ability to excrete these amounts4.
Geographic Latitude
Sunlight exposure is highest at the equator and decreases as you move farther north or south4.
Regulating Lipid Metabolism
Vitamin A is involved in lipid metabolism, helping to regulate the storage and use of fats in the body11.
Medications
Certain medications may interfere with the absorption or metabolism of specific vitamins4.
Vitamin D works with the parathyroid hormone (PTH) to reduce calcium loss through urine by enhancing its absorption in the kidneys and stimulating the release of calcium and phosphorus from bones4.
Skin Pigmentation
Darker skin, due to higher melanin levels, reduces the skin’s ability to absorb sunlight4.
Fat-Soluble Vitamins
Vitamins A, D, E, and K are absorbed into the lacteal within the villi of the small intestine. From there, they travel through the lymphatic system to the liver. Fat-soluble vitamins are absorbed alongside dietary fat, therefore, a low-fat meal can impair absorption. Fat-soluble vitamins are stored in visceral and subcutaneous fat, which makes it harder for deficiencies to develop. However, excessive intake of these vitamins can lead to toxicity as they accumulate in the body’s fat stores4.
Developed B12 Deficiency
Early B12 Deficiency
12
12
(can also present in vitamin B9 deficiency)
Primary Deficiency
An individual does not consume enough of a specific vitamin4.
Inadequate Intake
29
This type of deficiency is typically only seen in:
30
31
Secondary Deficiency
Arises from an underlying condition that limits the absorption or utilization of the vitamin. Lifestyle factors (e.g., smoking and alcohol use), medications, or other health conditions may influence these processes4.
Iron Uptake
Vitamin C enhances absorption of non-heme iron by converting it to a more readily absorbable form. In fact, Vitamin C is the only dietary supplement other than animal tissue that has been found to promote iron absorption43.
Visual Impairments
Created with BioRender.com.
Ozone and Air Pollution
Both block sunlight4.
Connective Tissue Formation
Vitamin C is key for the formation of intercellular ground substances of bone, dentin and other connective tissues such as blood vessels. Vitamin C is a co-factor in the activation of proline/lysine hydrolases that allow the cross-linking of proline and lysine residues in collagen44.
13
History of Scurvy
British sailors in the 19th century were called "limeys" because their tendency to consume citrus fruits (lemons, limes & oranges) to avoid scurvy on long voyages. However, today's cases are typically due to secondary causes such as old age and chronic alcohol use13.
Histologically seen as megaloblastic anemia
13
Did you know?
Vitamin C is the only essential vitamin not in high amounts in cooked animal foods! Only raw liver, fish roe, and eggs are known to contain sufficient amounts of Vitamin C53.
Genetics
Genetic variations can enhance or limit the body’s ability to absorb and utilize vitamins4.
Food Preparation and Cooking
Water-soluble vitamins are sensitive to destruction when boiled, over-cooked, or exposed to excessive light4.
Regulating Cell Growth + Differentiation
Vitamin A is essential for the normal differentiation of epithelial cells, which form protective linings in areas like the respiratory and digestive tracts 11, 12, 13.