Vitamins

Question 1

Vitamins:

Answer 1

• There are 13 vitamins – vitamins A, C, D, E, K, and the B vitamins (thiamine, riboflavin, niacin, pantothenic acid, biotin, B6, B12, and folate).
• Key functions of vitamins include:
- Supporting the immune system - Regulating gene expression
- Supporting neurological activity - Facilitating ATP production
- Manufacturing of blood cells - Regulation of hormones
• Vitamins are absorbed in the small intestine. It is, therefore, vital to optimise GIT health

Question 2

Vitamin-Dependent Enzymes:

Answer 2

• Vitamins are required for the activation
of vitamin-dependent enzymes (they hence function as ‘cofactors’).
• E.g. B-vitamins are vital cofactors for the action of the CYP450 enzyme system, needed for phase 1 liver detoxification. Therefore, B vitamins can be used as part of a liver support programme.

Question 3

Vitamins Classification:

Answer 3

1. Fat-soluble vitamins: A, D, E, K.
   • Fat-soluble vitamins are soluble in fats.
   • Absorbed with fat in the small intestine into the lymphatic capillaries and then into the blood. They are readily stored.
   • Tighter range between efficacy and toxicity than water soluble.
2. Water-soluble vitamins: B vitamins and vitamin C.
   • Water-soluble vitamins are soluble in water.
   • Absorbed in the small intestine directly into the blood. Storage is minimal (exception = B12), and easily excreted, if in excess.

Question 4

Vitamin A Facts:

Answer 4

• Vitamin A was the first vitamin to be discovered (hence ‘A’).
• The active forms (vitamers) which execute the functions of vitamin A are: Retinol, Retinal and Retinoic Acid.

Question 5

The 2 Forms of Vitamin A:

Answer 5

• Pro-vitamin A → converted into the active (usable) form of vitamin A (retinol) in the small intestinal epithelium and liver.

• Carotenes (or carotenoids) are examples of pro-vitamin A. The most active pro-vitamin carotenes are: α- (alpha), β- (beta) and γ- (gamma) carotenes and cryptoxanthin.
• Found in non-animal foods: Dark green, yellow / orange vegetables and fruit, e.g. carrots, squash, mango, spinach, sweet potatoes.

• Pre-formed vitamin A → this is active vitamin A the body can use as it is.
- Only found in animal foods: liver, fish liver oils, egg yolk, mackerel, salmon.

Question 6

Vitamin A Absorption:

Answer 6

Pro-vitamin A Absorption:
• Dietary carotenes are converted to vitamin A only as needed, so do not have toxicity concerns.
• absorption in the small intestine varies between 5% and 60%.
• Ensure that there are adequate healthy fats in the diet as carotenoids are fat-soluble (drizzle with coconut oil or olive oil)
• Another way to increase the bioavailability of carotenoids is to cook (slightly steam) these foods, e.g. carrots- to free carotenoids from cells.

Pre-formed Vitamin A Absorption:
• About 70-90% of dietary retinol is absorbed - this is a key reason that animal food sources of vitamin A can lead to vitamin A toxicity (liver particularly).

Question 7

Vitamin A functions:

Answer 7

Question 8

Vitamin A functions:

Answer 8

Question 9

Vitamin A functions:

Answer 9

Question 10

Vitamin A Deficiency Signs and Symptoms:

Answer 10

• Vision impairment at night is an early sign: Loss of sensitivity to green light, unable
to adapt to dim light and night blindness. Prolonged deficiency can lead to blindness.
• Hyperkeratosis of skin of upper arms.
• Reduced skin integrity – rough dry skin,
acne, eczema, poor wound healing. Dry hair.
• Poor bone growth / development.
• Poor sense of taste and smell.
• Lowered immunity (recurrent infections)

Question 11

Factors Affecting Individual Requirements for Vitamin A:

Answer 11

• Diabetes mellitus, thyroid & liver disease – ↓carotene conversion.
• Alcoholism: accelerates the breakdown of liver-stored retinol; absorption and carotene conversion is reduced. Increased vitamin A toxicity potential; not supplement with preformed A.
• Poor gut health (lack of absorption in small intestine) and conditions that affect fat absorption, e.g. cystic fibrosis, statins, etc.
• Zinc deficiency and/or protein malnutrition: zinc and protein are required to make Retinol Binding Protein (RBP). RBP moves vitamin A from liver storage to tissues for utilisation. Without zinc, vitamin A is trapped. So optimise intake of zinc-rich foods.

Question 12

Vitamin A Toxicity & Drug Interactions:

Answer 12

Vitamin A Toxicity: long-term and regular intake (roughly 5-10 times the recommended nutrient intake over many months):
• Can negatively affect gene regulation during embryological development leading to birth defects (e.g. cleft lip).
• May increase osteoclast activity and lead to bone fractures.
• Can damage hepatocyte cell membranes (causing liver disease).
• Can lead to hyperlipidaemia, amenorrhoea and anorexia.
• Can cause dry, red and scaling skin.

Vitamin A Drug Interactions:
• Be wary of vitamin A supplementation with those taking warfarin,
as it decreases vitamin K absorption (increasing bleeding risk).

Question 13

Vitamin D Facts:

Answer 13

• Vitamin D is not strictly a vitamin since it can be synthesised in the skin in response to sunlight.
• Dietary sources are only required in the absence of adequate sunlight (UVB), and include 2 types of vitamin D:
- Plant source: vitamin D2 (ergocalciferol D2) – found in mushrooms (fungi), but these require good sun exposure.
- Animal source: (cholecalciferol D3) – found in cod liver oil, oily fish (herring, mackerel, sardines, wild-caught salmon) and organic egg yolks.
• Vitamin D2 and D3 do not have any direct functions; they both first need to be converted (hydroxylated)- they both have the same activation pathway via the liver and then kidney.
• Levels over 50 nmol/L considered to be sufficient/below 25 nmol/L deficient, however the optimal range is generally considered to be 75-125 nmol/L

Question 14

Vitamin D Synthesis:

Answer 14

• If outside and your shadow is the same height or shorter than you are, you’re getting enough sunlight to make vitamin D.
• 10 minutes of summer sun exposure results in production of about 400IU in fairer skin types.
• Note that vitamin D can be stored in the liver for 4 months.

Question 15

Vitamin D supplementation:

Answer 15

• A supplemental dose of 4000IU/day has been used without adverse effects.
• Ergocalciferol is less than one-third as potent as cholecalciferol, so D3 is favoured for
supplementation. D3 supplements also stay in circulation longer.
• Pronounced deficiency: (<10 ng/mL) 50,000 IU of vitamin D3 orally once weekly for 2-3 months, or 3 times weekly for 1 month.

Question 16

Vitamin D Functions:

Answer 16

• A key function of vitamin D is to maintain serum calcium and phosphorus homeostasis. This balance impacts many body processes, including heart and nervous system functioning.
• The actions of vitamin D are mediated through a nuclear transcription factor known as the Vitamin D Receptor (VDR) within the nucleus of each cell. VDR activation is thought to directly and/or indirectly regulate 100 to 1,250 genes.

Question 17

Vitamin D Functions:

Answer 17

Question 18

Vitamin D Functions:

Answer 18

Question 19

Vitamin D Functions:

Answer 19

Question 20

Vitamin D Deficiency Signs & Symptoms:

Answer 20

• Rickets & osteomalacia – demineralised bones. Rickets occurs in children, whilst osteomalacia affects adults. Presents with bone pain and bowing of lower limb bones.
• Osteoporosis (brittle bones) – fractures.
• Severe asthma in children.
• Poor immunity or immune dysfunction (autoimmunity, allergies), insomnia, nervousness, depression.
• Menstrual irregularities (increases FSH / LH production).
• Non-specific musculo-skeletal pain and fatigue

Question 21

Causes of vitamin D deficiency:

Answer 21

• Inadequate UVB sun exposure and overuse of conventional sunscreens.
• Dietary factors such as excessive animal protein or calcium intake can lead to
lower blood levels of vitamin D by affecting its rate of formation and clearance.
• Lack of dietary fats (it is a fat-soluble vitamin), and a lack of magnesium (it is a co-factor for vitamin D synthesis.
• Breastfeeding without adequate sunlight / supplementation.
• Impaired liver functionality (compromised vitamin D conversion) due to excess alcohol, drug and caffeine use, as well as a large toxic burden from the diet (e.g. pesticides), environmental
and household chemicals. Therefore, it is crucial to support liver functionality by removing the toxic burden, etc.
• Elderly patients and those with a history of kidney disease.
• Poor intestinal absorption of dietary vitamin D (e.g. due to cystic fibrosis, coeliac disease, dysbiosis) and a lack of bile. Therefore, it is crucial to support digestive health (i.e. good digestive secretions, a healthy microflora).

Question 22

Vitamin D Toxicity & Vitamin/Drug Interactions:

Answer 22

• Main toxicity symptoms due to vitamin D-related hypercalcaemia: nausea, diarrhoea, vomiting, weakness, hypertension, constipation.
• Toxicity can occur taking supplemental vitamin D at more than 50,000 IU per day for one to several months.
• toxicity= blood levels above 375 nmol/L.
• EFSA Tolerable Upper Intake Level for Adults: 4000 IU/day.

Drug Interactions:
• Osteomalacia risk due to low vitamin D is increased with use of barbiturates and anticonvulsants.

Vitamin A & D Interaction:
• The balance of vitamin A and D is essential for proper gene transcription and crucial for correct gene expression- disease prevention

Question 23

Vitamin E Facts:

Answer 23

• 2 families: Tocopherols & Tocotrienols. Both families contain at least four forms: alpha, beta, gamma & delta. All forms exist within natural foods.
• The only form recognised for human nutrition is α-tocopherol.
• Up to 80% of vitamin E is destroyed by freezing, whilst heating destroys around 30% of vitamin E.
• Fresh, raw food sources are best: Sunflower seeds, almonds, pine nuts, olive oil, avocado, sweet potato, spinach.
• Naturally sourced vitamin E = d-alpha-tocopherol.
Synthetically produced form = dl-alpha-tocopherol. Synthetic forms of vitamin E are derived from petroleum oil and should be avoided❗️

Question 24

Vitamin E Functions:

Answer 24

Question 25

Vitamin E Deficiency & Toxicity:

Answer 25

Deficiency:
• A marginal subclinical deficiency is common. Serious deficiencies are rare unless significantly impaired absorption (i.e. cystic fibrosis).
• Typically presents as:
- Red blood cell destruction (due to erythrocyte oxidation
→ haemolytic anaemia) – exhaustion after light exercise.
- Easy bruising and slow healing (fewer antioxidants).
- Nerve damage (e.g. neuropathy) due to oxidation.

Toxicity (rare):
• High doses with vitamin K deficiency and/or warfarin, can increase bleeding risk. Caution supplements with chemotherapy. High supplement doses create potential for pro-oxidant effect.

Question 26

Vitamin K:

Answer 26

3 forms:
• K1 (Phylloquinone): the dietary source found in green leafy vegetables – natural form, making up about 80-90% of daily intake. K1 must be converted to K2 in the body to be utilised.
• K2 (Menaquinones): synthesised by bacteria, found in fermented foods, making up around 10%. Probiotics can support intestinal K2 production. K2 synthesis by bacteria occurs in the human jejunum and ileum, and is absorbed to a limited extent.
• K3 (Menadione): a potentially toxic, synthetic form used in livestock.

Richest Food Sources:
• Natto and dark green leafy vegetables (best absorbed with some dietary fat, e.g. steamed broccoli and kale with extra virgin olive oil).

Question 27

Vitamin K Dosage & Absorption:

Answer 27

• Optimal intake is 300-500mcg/day.
• Only small amounts are stored (mainly in the liver) and a regular dietary supply is require. ~30-40% of ingested vitamin K is retained – the rest is excreted.
• Reduced absorption: High vitamin A intake, aspirin. Low bile secretion and poor fat absorption disease states

Question 28

Vitamin K Functions:

Answer 28

Question 29

Vitamin K Deficiency:

Answer 29

Causes of vitamin K deficiency:
• Liver diseases, warfarin, antibiotic-use, fat malabsorption issues.
• Maternal considerations: vitamin K transfer to the foetus via the placenta is not significant (although it is generally adequate). Maternal medications such as antibiotics, anticonvulsants and warfarin can dramatically reduce stores.
• A vitamin K injection is offered at birth to newborns to prevent potential haemorrhagic disease❗️

Deficiency signs and symptoms:
• Excessive bleeding (haemorrhages), bruising, bone fractures, soft tissue calcification.

Question 30

Vitamin B1 - Thiamine

Answer 30

• Vitamin B1 (thiamine) functions in the body as the active form ‘thiamine pyrophosphate’ (TPP); conversion to this enzyme is dependent on magnesium, and impaired by alcohol.
• Bodily stores of B1 would last for ~ 1 month.
• B1 content is very easily reduced by processing including milling, chopping, canning, adding sulphites (e.g. dried fruit), baking soda. Boiling or freezing reduces B1 content by 50%. Toasting bread reduces B1 by 30%. Fresh, raw sources are best❗️

Food sources:
• Yeast extract, peas, oranges, nuts (e.g. macadamia), pulses, sunflower seeds, wholegrains, meat / fish.

Question 31

Vitamin B1 (Thiamine) Functions:

Question 32

Vitamin B1 (Thiamine):

Answer 32

Dietary requirements:
• The more carbohydrate you eat, the more B1 you need (i.e. to create ATP from it).

Absorption is impaired by:
• Alcohol, tea (tannins), coffee, the OCP, stress and antacids.

Deficiency (Beriberi):
• Beriberi is the primary deficiency disease. Most forms are rare in the West. A white rice diet is thiamine depleted (these are at risk).
• Alcoholics are particularly prone to deficiency – ‘cerebral beriberi’ (Wernicke-Korsakoff syndrome) is most common Western cause.

Question 33

Vitamin B1 (Thiamine) Deficiency & Toxicity:

Answer 33

Symptoms of subclinical deficiency:
• Depression, irritability, fatigue, memory loss, muscle weakness and cramps, GIT disturbance.
• elderly people are frequently more depleted of thiamine

Toxicity:
• Only seen in supplementation, but is rare.

Question 34

Vitamin B2 - Riboflavin

Answer 34

• vital for energy production and the metabolism of carbohydrates, fats and protein.
• fluorescent green/yellow compound – supplements over 27mg (maximum absorbed amount) will colour urine bright yellow
• very sensitive to light, and content is also reduced by heating/boiling, freezing and leeching into cooking water (yellows the water).

Food sources:
Yeast extract, spinach, wild salmon, mushrooms, almonds, quinoa, lentils, kidney beans, organic eggs, meat.

Question 35

Vitamin B2 (Riboflavin) Functions:

Question 36

Vitamin B2- Riboflavin

Answer 36

Absorption:
• Maximum absorption from a single dose is 27mg. Bile salts help intestinal absorption. Antacids and alcohol impair absorption.
Bioavailability is impaired by:
• Copper, zinc, caffeine, theophylline (in chocolate), saccharin.

Dosage:
• Doses between 90-400mg per day (split through the day).
• Smoking can reduce levels in the body. B2 demands are increased with heavy exercise, pregnancy and ageing.
Do not exceed daily recommendations in pregnancy and lactation❗️

Toxicity: Generally considered non-toxic.

Question 37

Vitamin B2 - Riboflavin

Answer 37

Deficiency:
• Depletion is common but deficiency is rare. More likely to occur in combination with other water-soluble vitamin deficiencies.

Signs & Symptoms of poor intake include:
• Sores at the margins of the lips / mouth corners.
• Red, dry, athropic tongue.
• Scaly dermatitis (especially around the mouth, nose, eyes and ears) and red, tired and gritty eyes.
• Fatigue, weakness, poor concentration, depression.
• Deficiency (although rare) can also cause alopecia.

Question 38

Vitamin B3 - Niacin

Answer 38

• Vitamin B3 is not strictly a vitamin as it can be synthesised by the body from the amino acid tryptophan: (60mg of tryptophan produces 1mg niacin).
• Vitamin B3 is only essential when tryptophan metabolism is altered❗️
• The two compounds with niacin activity are: nicotinic acid & nicotinamide. The active forms of niacin are: NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate), which are energy carrying molecules.
• Food sources: Mushrooms, green leafy vegetables, yeast extracts, sunflower seeds, salmon, sardines, peanuts, avocado,
meat and poultry. Cooking reduces B3 in foods.
Tryptophan-rich foods, e.g. bananas, turkey.

Question 39

Vitamin B3 - Niacin

Answer 39

• Synthesis of B3 from tryptophan requires B2, B6 & iron (cofactors).
• Niacin flush: Skin flush & itch due to supplementation (Avoid flush by using initial dose of 25mg
(gradually increased) alongside 1g vitamin C).

Absorption & Storage:
• Absorption of vitamin B3 is in the small intestine.
• Stored niacin (NAD) is mostly in the liver, heart, muscles and kidney.

Question 40

Vitamin B3 - Niacin Functions:

Question 41

Vitamin B3 - Niacin Deficiency/Insufficiency:

Answer 41

Deficiency Signs & Symptoms:
• Severe deficiency (‘Pellagra’): four Ds – diarrhoea, dermatitis (characteristic collar rash), dementia, death (within 4-5 years). Pellagra can occur in diets deficient in both protein and niacin. It is common in Africa, Indonesia and China. In the West, pellagra is associated with homelessness, alcoholism, or anorexia nervosa. Crohn’s or intestinal disease may also lead to deficiency. Pellagra is treated with up to 500mg B3 daily by a doctor.

• Mild deficiency / insufficiency symptoms:
Unrelenting fatigue, vomiting, depression, indigestion, canker sores, sensitivity to strong light, red tongue and inflamed gums.

Question 42

Vitamin B3 - Niacin Toxicity:

Answer 42

• Adverse events can occur at high levels: hypotension, hyperuricaemia, flush, hypothyroidism, hepatotoxicity
• Niacin competes with urate for excretion so supplementation can worsen gout❗️

Question 43

Vitamin B3 - Niacin Toxicity:

Answer 43

• Adverse events can occur at high levels: hypotension, hyperuricaemia, flush, hypothyroidism, hepatotoxicity
• Niacin competes with urate for excretion so supplementation can worsen gout❗️

Question 44

Vitamin B5 – Pantothenic Acid

Pantothenic = from Greek for ‘found everywhere’ (i.e. found in many foods

Answer 44

• required to make coenzyme A (CoA)- energy production ❗️ In this active form it is involved in hundreds of different reactions.

Food Sources:
• Richest food sources include shiitake mushrooms, avocados, nuts, seeds, fish and meat. However, it is found widely distributed in almost all foods – hence the name.
• Synthesised by intestinal bacteria, but to as yet unknown level of absorption. Theoretically, antibiotics may reduce synthesis.
• Sensitive to processing, cooking and freezing with up to 80% loss.

Question 45

Vitamin B5 – Pantothenic Acid Functions:

Question 46

Vitamin B5 – Pantothenic Acid Deficiency & Toxicity:

Answer 46

Deficiency:
• Deficiency is rare. However, depletion may occur with high alcohol use, prolonged stress and recent surgery.
• Deficiency Symptoms: burning sensation in feet and tender heels, fatigue and abdominal distress❗️

Toxicity:
• No known toxicity.

Question 47

Vitamin B6 - Pyridoxine

Answer 47

• Vitamin B6 is made up of a group of six related vitamers. Active B6 is involved in over 100 enzymatic reactions. The active forms are pyridoxal 5’-phosphate (PLP) and pyridoxamine 5’-phosphate (P5P).

Food Sources:
• Widely distributed: wholegrains, green vegetables, sunflower seeds, pistachios, walnuts, bananas, lentils, avocados, meat & fish.
• Vitamin B6 in a varied diet is approximately 75% bioavailable. Intestinal flora synthesises large amounts but absorption is unknown.
• Processing, preserving, heating and light exposure reduce B6. Alcohol excess, the OCP and GIT issues increase requirements.

Question 48

Vitamin B6 - Pyridoxine Functions:

Question 49

Vitamin B6 - Pyridoxine

Answer 49

Increased need for vitamin B6 occurs in:
• Alcohol dependence, long periods of high stress, pregnancy – particularly in third trimester, hormonal imbalances, hyperhomocysteinemia (with folate/folic acid and vitamin B12).

Deficiency:
• Deficiency is rare, and occurs alongside other deficiencies.
• Symptoms: Low B6 affects the metabolism of fatty acids leading to skin lesions and dermatitis. Tongue inflammation, recurrent mouth ulcers and sores on the corners of the mouth, hormonal imbalance (e.g. PMS), anaemia (fatigue, pallor etc.), depression.

Question 50

Vitamin B6 - Pyridoxine Drug Interactions & Toxicity

Answer 50

Drug Interactions:
• Many drugs deplete B6 levels and so intake should be increased, eg. anticonvulsants, antibiotics, alcohol, chemotherapy drug ‘docetaxel’ and the oral contraceptive pill (OCP).
• Levodopa (Parkinson’s medication) - the combination of carbidopa and levodopa do not have the B6 depletion problem. However levodopa (on its own) is broken down by B6 so it should not be supplemented (beyond 5-10mg/day).

Toxicity:
• 100-200mg/day supplements long term can lead to toxicity symptoms including neuropathy, acne, headache, nausea.

Question 51

Vitamin B7/B8/H – Biotin

Answer 51

• Biotin as a vitamin was discovered due to its deficiency state brought about by raw egg consumption (at about 30% of the diet for many weeks to years). It is considered part of the B-vitamin complex and has no known toxicities.
• Raw egg whites contain a protein called avidin which joins with biotin making it unabsorbable. Avidin is denatured by cooking.
• Biotin is an otherwise relatively stable B vitamin. Widespread in foods but only in small amounts (micrograms) and also made by intestinal bacteria.

Food sources include: Egg yolk, yeast, wholegrains, cauliflower, sweet potato, nuts, meat, oily fish.

Question 52

Vitamin B7/B8/H – Biotin Functions:

Question 53

Vitamin B7/B8/H – Biotin Deficiency:

Answer 53

Deficiency:
• Symptoms: Dermatitis, dry scaly flaky skin (i.e. mouth and nose), smooth pale tongue, hair thinning and loss, depigmentation.
• Intestinal production can be reduced due to prolonged use of antibiotics. A vegetarian diet may enhance biotin synthesis and absorption.
• Anticonvulsant drugs and alcohol may inhibit absorption. Steroid hormones and anticonvulsants may hasten breakdown of biotin in tissues. Biotin supplementation interferes with laboratory tests.

Question 54

Vitamin B9 - Folate

Answer 54

• The active form of folate in the body is THF (tetrahydrofolate), and its methylated derivatives. As part of an enzyme complex, folate is active in numerous metabolic reactions.
• Folic acid is a synthetic supplement or fortification form and is not found in nature. Folinic acid and levomefolic acid are also synthetic forms of this vitamin. These synthetic forms can be dangerous, so should be avoided.

Folate Food Sources:
• Leafy greens, asparagus, avocado, Brussel sprouts legumes, citrus fruit (especially oranges) and liver.

Question 55

Vitamin B9 - Folate Absorption & Bioavailability:

Answer 55

• Absorption requires adequate pancreatic enzymes. After absorption, a methyl group (–CH3) is added to folate and in this form, it is delivered to body cells.
• Without the vitamin B12 enzyme which removes the methyl group, folate becomes trapped inside cells in its methyl form (5-methyl THF), unavailable to perform its main functions (DNA synthesis and cell growth) – a metabolic situation called the ‘folate trap’.
• Losses occur from processing & cooking foods. Main storage site is the liver (50%). Some folate is recycled in the liver and reabsorbed. The microbiota produce some B9, but absorption/use is not known.

Question 56

Vitamin B9 - Folate Functions:

Answer 56

The functions of folate relate to its methyl donor action, including:

Question 57

Vitamin B9 - Folate

Answer 57

Deficiency signs and symptoms:
• Affecting rapidly dividing cell types; skin, GIT and blood cells – skin and digestive issues, megaloblastic anaemia (severe deficiency).

Factors related to deficiency:
• Alcoholism, OCP, diuretic and aspirin use. GIT disorders, diets low in green leafy vegetables and old age. Those on methotrexate and anticonvulsants should consult their GP regarding vitamin B9 use❗️

Dosage for conception:
• Preconception and conception care: 600mcg/day beginning prior to conception helps avoid neural tube defects.

Question 58

Vitamin B9 - Folate Safety Considerations:

Answer 58

• Naturally occurring folate is considered safe to use.
• Folic acid supplements mask the megaloblastic anaemia of vitamin B12 deficiency and may hasten the development of irreversible nerve damage. B12 testing can combat this.
• People with an MTHFR polymorphism may be more susceptible to issues arising from supplementation with folic acid (or that in fortified foods). Active forms of the vitamin ONLY should be recommended to clients.
• Folic acid supplements have the most drug interactions of all vitamins; check rigorously 🚩

Question 59

Vitamin B12 - Cobalamin

Answer 59

• Vitamin B12 refers to a family of cobalamin compounds containing the essential mineral cobalt in the centre.
• The most active B12 analogs include: methylcobalamin, hydroxycobalamin, adenosyl cobalamin and cyanocobalamin. These are the only analogs recognised by the body. There are others found in nature but they are not bioavailable to humans❗️
• Vitamin B12 is synthesised by bacteria. Vitamin B12 found in animal based foods originates from their ingestion of bacterial- contaminated feed, or from B12 that has been given to the animal. The human microbiota produces B12, but it is not absorbed.

Question 60

Vitamin B12 - Cobalamin Vegan & Animal Food Sources:

Answer 60

B12 storage in the liver lasts between 3-5 years❗️

Vegan B12 Food Sources:
• Chlorella pyrenoidosa (e.g. 9g per day), Korean purple laver (Porphyra sp.)
• Nutritional yeast, nori and kombu sea vegetables (nori, kombu, kelp and dulse), shiitake & Lions mane mushrooms.

Animal B12 Food Sources:
• Meat, liver, milk, cottage and feta cheese, organic eggs, fish (esp. sardines, mackerel and wild salmon)

Question 61

Vitamin B12 - Cobalamin Functions:

Question 62

Vitamin B12 - Cobalamin

Answer 62

Causes of B12 deficiency:
• Poor nutrition (malnutrition):
- Lack of dietary B12 intake, and a diet rich in highly processed, nutrient-depleted foods.

• GIT causes (malabsorption):
- Stomach problems (e.g. lack of intrinsic factor, low hydrochloric acid production)
- Low pancreatic enzymes, small intestine issues (e.g. Crohn’s disease, coeliac), high alcohol.
• Note: if a client has a good dietary intake of B12, yet is deficient, it highlights a possible absorption issue or problem with methylation.

Deficiency States:
• The most common cause of deficiency is malabsorption due to inadequate intrinsic factor (IF) production. It is called pernicious anaemia. Helicobacter pylori infection is also implicated.
• Pernicious anaemia is associated with an autoimmune attack on parietal cells in the stomach (the cells that synthesise intrinsic factor).
• Increased vitamin B12 requirements are associated with: pregnancy, thyrotoxicosis, malignancy, liver & kidney disease

Question 63

Vitamin B12 - Cobalamin Deficiency:

Answer 63

Deficiency Signs and Symptoms:
• Megaloblastic anaemia: presenting as fatigue, breathlessness, pallor, etc. Supplementation with B9 will alleviate the anaemia, however other symptoms of vitamin B12 deficiency progress.

• Neurological abnormalities: tingling, numbness, loss of balance, burning sensations, weakness, confusion and decreased reflexes.

Question 64

Vitamin B12 - Cobalamin Toxicity & Drug Interactions

Answer 64

Toxicity:
• Vitamin B12 is one of the safest vitamins❗️ No adverse effects have been associated with large intakes (2mg) of vitamin B12 from food or supplements in healthy people.

Drug Interactions:
• The OCP, metformin, excessive alcohol, proton pump inhibitors and H2-receptor antagonists lower B12 levels.
• Calcium may enhance B12 absorption, including with metformin use.
• People with autoimmune disease are considered more at risk of pernicious anaemia.

Question 65

Vitamin C – Ascorbic Acid

Answer 65

• functions as a key antioxidant, and as an enzyme cofactor in the body
• Vitamin C does not need to be modified by the body to function.
• Until the ‘cure’ for the vitamin C deficiency disease ‘Scurvy’ was found, more sailors died of scurvy than of any other cause (estimated 2 million sailors or 50% of any major voyage crew)❗️

Question 66

Vitamin C – Ascorbic Acid Food Sources:

Answer 66

• All fresh raw fruit and vegetables, particularly peppers, kiwi fruit, papaya, currants, berries, citrus, crucifers, mangoes and tomatoes.
• Very significant losses occur as vegetables wilt, or when they are cut as a result of the release of ascorbate oxidase from the plant tissue.
• Ascorbate oxidase is why lemon or lime juice can prevent the browning (oxidising) of other foods
(e.g. sliced apple) – the vitamin C creates an antioxidant barrier from oxygen until it is all used up.

Question 67

Vitamin C – Ascorbic Acid Absorption:

Answer 67

• Absorbed in the mouth and in the small intestine (by active and passive means). Up to 100% absorption per 200mg serving.
• Transported into cells by glucose transporters; so high blood glucose levels can inhibit vitamin C uptake significantly. Think about diabetics and clients with sugar laden diets. High doses of vitamin C can also skew blood glucose test results❗️
• Vitamin C concentrates in the adrenal glands, white blood cells, thymus and pituitary – although there is no specific storage site❗️
• Factors that increase breakdown or excretion of vitamin C include:
Stress – psychological, chemical, emotional or physiological, fever and viral illnesses. Alcohol, smoking, heavy metals, aspirin, OCP.

Question 68

Vitamin C – Ascorbic Acid Functions:

Answer 68

Question 69

Vitamin C – Ascorbic Acid Functions continued:

Question 70

Vitamin C – Ascorbic Acid Deficiency:

Answer 70

Deficiency Signs and Symptoms:
• The two most notable signs of vitamin C deficiency reflect its role maintaining blood vessel integrity:
- The gums bleed easily around the teeth.
- Capillaries under the skin break spontaneously producing pinpoint haemorrhages.
• When intake falls to about 1/5 of its optimal store size (approx. 1 month on a vitamin C depleted diet), Scurvy symptoms appear:
- Further haemorrhaging from inadequate collagen synthesis.
- Muscle degeneration and rough, brown scaly skin.
- Wounds do not heal. Bone rebuilding falters
- fractures develop.

Deficiency States:
• During stress, the adrenals release vitamin C with other hormones into the blood. The exact role of vitamin C in stress is unknown, but it is known that stress raises vitamin C needs – likely due to additional free radical damage.
• Burns, infections, toxic metal intakes, chronic use of medications and cigarette smoking are among the stresses that increase vitamin C demand.
• Smokers have lower levels of serum vitamin C – 25mg of vitamin C is lost with every cigarette smoked.
• susceptibility to infections, poor wound healing, fatigue, skin and gum degeneration, petechiae.

Question 71

Vitamin C – Ascorbic Acid Toxicity & Drug Interactions:

Answer 71

Toxicity:
• Vitamin C is non-toxic❗️, even at extremely high doses (unabsorbed ascorbate from very high doses is a substrate for intestinal bacterial metabolism causing gastrointestinal discomfort and diarrhoea.
• People with kidney disease and those with a tendency toward gout are prone to forming kidney stones if they take large doses of Ascorbic Acid beyond a few months
• Be mindful of high dose vitamin C with haemochromatosis.

Drug interactions:
• May reduce effectiveness of warfarin, statins, some cancer drugs. Increases oestrogen therapy effects.
*Skews diabetes test results❗️