W5 L1 - Intro to Vitamins and Minerals Flashcards
Role of vitamins and minerals
- necessary in small amounts for life and growth
- involved in metabolism, cell reproduction, tissue repair
- can act as co-factors for enzymes
- can have an anti-oxidant effect
effect of vitamin/mineral deficiencies
- disease
what are vitamins
- Organic molecules
- Obtain from food or supplements - body does not make sufficient quantities
- Only two vitamins (vitamin d and vitamin k) can be made by the body from non-dietary sources
examples of water soluble vitamins
Vitamin C (Ascorbic acid)
Vitamin B1 (thiamine)
Vitamin B2 (riboflavin)
Vitamin B3 (niacin)
Vitamin B5 (pantothenic acid)
Vitamin B6 (pyridoxine)
Vitamin B7 (biotin)
Vitamin B9 (folate/folic acid)
Vitamin B12 (cobalamin)
where are water soluble vitamins absorbed
- most in upper small intestine (duodenum)
- vitamin B12 is an exemption, absorbed in ileum by binding to intrinsic factors
- rapid absorption
- vitamin b12 and folate (b9) absorption independent of sodium but others are absorbed by sodium cotransporters
examples of fat-soluble vitamins
Vitamin A
Vitamin D
Vitamin E (tocopheryl)
Vitamin K
where are fat-soluble vitamins are absorbed
- by bile in large intestine
- Absorption can be reduced if fat absorption is decreased e.g. by lack of pancreatic enzymes/low fat diet
- Vitamin K – many subtypes produced by GI flora from original plant sources then absorbed
- Vitamin D – dietary but also synthesised in skin via cholesterol by sunlight
which types of vitamins are stored
- fat-soluble
- water soluble aren’t stored
Examples of vitamin deficiencies
A - Poor night vision/night blindness
B1 - Fatigue, loss of appetite, weight loss, GI effects
B2 - Soreness of mouth and tongue, itching eyes, loss of vision
B3 - GI effects, skin changes, tremors
B5 - Fatigue, heart and digestive issues
B6 - Depression, vomiting, increased susceptibility to disease, anaemia
B7 - Skin inflammation, conjunctivitis
B9 (folic acid) - Anaemia, digestive disorders, palpitations, behavioural disorders
B12 - Pernicious anaemia and neurological issues
C - Scurvy, aching joints, generalised weakness
D - Bone changes e.g. osteoporosis, poor immune function
E - Anaemia and nerve damage
K - abnormal clotting
what are minerals and their function
- inorganic substances
- functions - Formation of bones and teeth
Essential constituents of body fluids, tissues and blood
Components of enzyme systems
Nerve function
examples of minerals
Calcium
Sodium
Magnesium
Potassium
Chloride
Phosphorus
Iron
Iodine
Selenium
Zinc
Copper
sources of minerals
- Food and supplements
- No one food provides all
- Need healthy balanced diet
- Water is also a source
absorption of minerals affected by
- Presence of other minerals/vitamins
- Components found in food
Amount of mineral already in body
Mineral deficiencies
- Potassium and Magnesium - cardiac arrhythmias
- Calcium and Magnesium - osteoporosis
- Calcium and Magnesium - muscle cramps and tetany
- Zinc - hair loss and poor wound healing
- Iron - anaemia
- Copper - Wilson’s disease
What are DRVs
- Dietary Reference Values (DRVs).
- These are a series of estimates of the energy and nutritional requirements of different groups of healthy people in the UK population. They are not recommendations or goals for individuals
- Reference Nutrient Intakes (RNIs)
- Lower Reference Nutrient Intakes (LRNIs)
- Estimated Average Requirements (EARs)
- Safe Intake
For most vitamins and minerals, DRVs are given as RNIs
Recommendation during pregnancy
- 400μg folic acid supplement daily until 12th week of pregnancy
- Prevents birth defects of the central nervous system
- If family history of neural tube defects - higher dose of 5mg of folic acid daily recommended
- Women with diabetes and those taking anti-epileptic medicines may also need to take a higher dose of folic acid
Recommendation for children
Vitamin D
- Breastfed babies (birth to one year of age) - daily supplement containing 8.5 - 10μg of vitamin D
- Babies fed infant formula – not required unless < 500ml of infant formula a day as formula milk fortified
- Children aged 1 to 4 years old - daily supplement containing 10μg of vitamin D
- Considera vitamin D supplement containing 400–600 international units (IU) daily age 4-18
NICE CKS vitamin d deficiency children
Vitamins A and C
- Children aged six months to five years – daily supplement of vitamins A and C (often combined with vitamin D)
- Precautionary measure - ensure requirements are met (difficult to be certain diet provides a reliable source)
- Babies fed infant formula – not required until receiving less than 500ml of infant formula a day
Vitamin D recommendations
- Adults with risk factors should take a daily supplement containing 400 international units (IU) of vitamin D throughout the year
- Other adults should consider taking a daily supplement containing 400 IU of vitamin D, particularly in the autumn and winter
- Do not routinely monitor serum vitamin D levels
- Check calcium intake
- Lifestyle advice to reduce risk of deficiency
People at higher risk of deficiency include those:
- With limited sun exposure
- With dark skin (for example African, African-Caribbean, or Asian or Middle-Eastern ethnic origin)
Vitamin D deficiency can also occur in people who:
- Are at increased risk of nutritional deficiency
- Are pregnant or breastfeeding
Are elderly (65 years and older)
- Have certain conditions or are taking certain drugs
- Are obese or have had gastric bypass surgery
- Have a family history of vitamin D deficiency
What’s the healthy start scheme
Pregnant or child under 4 - could get Healthy Start vouchers to help buy some basic foods and supplements
Additional groups of people who may benefit from supplementation
- Some vegans
- People in certain demographic groups
- Chronic alcoholism - poor diet and poor GI absorption
- Innate GI malabsorption e.g. coeliac, inflammatory bowel disease (IBD)
- Chronic kidney disease (CKD) – vitamin D
- If prescribed certain medications e.g. isonazid
What’s fortification
adding vitamins, minerals, or other nutrients to food and beverages that don’t naturally contain them or contain them in lower amounts
examples of fortification
Addition of nutrients to appropriate food vehicles e.g.
- Vitamin D fortified margarine
- B vitamins and iron in cereals
- White and brown flour fortified with calcium, iron, thiamine and niacin
- Fluoride in drinking water
Considerations with Supplements
- Market for dietary supplements grown dramatically over past 30 years
- They do not make a bad diet good!
- Most used by the “worried well”
What are they: - Contain vitamins, minerals and often other ingredients
- People believe they will have a beneficial effect on health
- Beliefs encouraged by media and marketing - targeted to demographics i.e. young men, older women, children, stressful jobs etc.
- Lacking in evidence - often anecdotal, misinterpretations of research
Problems with Supplements
- Toxicity and accumulation e.g. iron
- Supplements are expensive
- Cause complacency - bad diet
- Legal status practically no control
- Dose, claims quality control, availability
- Not viewed as a medicine – thus difficult to offer advice
- Interactions with medicines
- Good Practice – Always ask patients about any supplement they take
