Nutrition Flashcards
Describe the main nutritional requirements for infants at six months.
Iron
Energy and protein - due to early rapid development
Why is exclusively breastfeeding recommended for the first six months of a baby’s life instead of formula?
Whilst both are completely nutritional complete, breast milk in the first few days of life known as colostrum also has secreted IgA which paints the GI tract with protection.
Although recommended for six months, any breastfeeding will have some benefit.
Describe the recommended formula milk from a Newborn to a Toddler at 3 years old.
From Newborn up to the age of one, Newborn formula milk can be recommended which is nutrient rich. However at six months it is recommended to switch to a formula that has a higher iron content known as follow on milk as iron stores at six months begin to become depleted from birth.
From the age of 1 to 3 toddler milk is recommended.
Give a couple of examples of each type of formula (Newborn, Follow on and Toddler).
Newborn - SMA PRO 1, SMA Extra-Hungry, C&G first milk
Follow on- SMA PRO 2, C&G follow on
Toddler milk- SMA PRO or C&G toddler milk
What milks are available for babies with a cow milk protein allergy?
Soya based milks such as SMA Soya, Infasoy
However there are concerns about using these milks before six months because soya can be allergenic and the immune system has not developed before six months
When is extensively hydrolysed formulas recommended?
These formulas are hypoallergenic and therefore recommended for babies with lots of allergies
Example Nutramigen
When else would you recommend specialised formulas?
Lactose free milks
Anti-reflux
Higher energy milks if premature
Colic
Why is it recommended at six months to wean?
Babies have higher nutritional requirements that can no longer be met by breast or formula milk alone
Introduce solid foods
What foods should be avoided if you wean before six months?
Due to the potential of creating allergies:
Wheat and gluten
Fish and shellfish
Fruit juices
Soya and eggs
What foods should be avoided in the first year of life?
Salt
Sugar
Honey
What nutritional requirements are recommended for pre-school children?
Increase in energy, protein, vitamins and mineral requirements
They should have a varied diet, with smaller portions but are nutrient dense
Whole milk is required
What are some of the common diet related complications in pre school children?
Fussy eating
Toddler diarrhoea
Constipation
Anaemia
Dental caries (avoid fruit juice)
Describe the main nutritional requirements for school aged children.
Healthy eating with a varied diet
Protein, Calcium, Iron, Vitamin A and D
Adjunct to diet, physical activity is also important
Describe the main nutritional requirements for adolescent girls.
Iron - due to menstruation onset
Calcium and Vitamin D - peak bone mass towards the end of adolescence, lack of Calcium and Vitamin D during adolescent leads to a low peak bone mass, which increases the risk of osteoporosis onset post-menopause. Physical activity also increases muscle mass
Energy and protein - due to growth spurts, (boys have extra nutrient requirements due to increased muscle mass)
What are the main nutrient requirements for adults (aged 19-64 years)?
Dependent on exercise, but the average is:
Energy-
Males- 2772kcal per day
Females - 2175kcal per day
Protein-
0.75g/kg of body weight
Carb-
50% of total energy, less than 5% from sugars
30 grams/day of fibre
Fat-
35% total energy, 11% of total saturated
Increase OMEGA-3 from fish and are bio-active- essential fatty acids and anti-inflammatory effects
What are some of the alcohol recommendations?
14 units per week maximum spread over 3 days a week
Several drink free days a week
Increased risk of cancer
Describe the main nutritional requirements during pregnancy.
Energy - only increases by 200kcal a day
Protein - only increases by 6 grams a day, during lactation an increase of 11 grams a day
Iron - particularly important in the last semester due to increase in blood volume and foetus size, more red blood cells going around the body
Folic acid - 400 micrograms during first trimester (usually as a supplement) after than then the foetus has fully developed and is just growing
What nutrients should be avoided during pregnancy?
Avoid shark, marlin, tuna as methyl mercury can accumulate in these foods which are teratogenic
Avoid alcohol and limit caffeine
Avoid Vitamin A (more than 1500 micrograms), liver and liver products
Describe the main nutritional requirements for old industrialised people.
Vitamin D - due to lack of sunlight
Calcium - only if osteoporotic
Energy and protein - decrease with age but malnutrition can occur
Micronutrients stay the same
Why does Malnutrition occur in the elderly population?
Inadequate intake of dietary energy leading to loss of body weight
Nutrient deficiencies - may be due to chronic disease
Widespread metabolic physiological and functional adaptations occur
Describe the main nutritional requirements for smokers.
Anti-oxidant rich diet - Vitamin C due to pro-oxidants in cigarettes so to neutralise them
What are dietary reference values?
They are a series of estimates of the energy and nutritional requirements of different groups of healthy individuals in the UK population.
What are the four types of dietary reference values?
Estimated average requirements (EARs)
Reference nutrition intakes (RNI)
Lower reference nutrition intakes (LRNI)
Safe intake
Define the estimated average requirements.
The EAR is an estimate of the average requirement of energy or a nutrient needed by a group of people (i.e. approximately 50% of people will require less, and 50% will require more)
When is estimated average requirements used in preference to the reference nutrition intake?
In regards to energy as energy requirements are dependent on so many factors such as exercise frequency, basal metabolic rate and therefore an average should be set rather than a reference nutrition intake (enough for 97.5% of the population) as for some people with would be a significant over-estimate of how much they require and would lead to obesity.
Define the reference nutrition intake.
The RNI is the amount of a nutrient that is enough to ensure that the needs of nearly all a group (97.5%) are being met.
This is the most commonly used dietary reference value.
Define the lower reference nutrition intake.
The LRNI is the amount of a nutrient that is enough for only a small number of people in a group who have low requirements (2.5%) i.e. the majority need more
Define the safe intake.
When there is insufficient evidence to set an EAR, RNI or LRNI.
The safe intake is the amount judged to be enough for almost everyone, but below a level that could have undesirable effects. For example Vitamin E
If you extracted anti-oxidants out of fruit and vegetables would you still experience the benefits if you took them as individual supplements?
No, it is theorised that vitamins and minerals have a synergistic effect and therefore work together to provide benefit to the individual.
Is Vitamin D beneficial for preventing the infections?
Some evidence to say it has some benefit
Is Vitamin C beneficial for the common cold?
No, there is no direct benefit taking Vitamin C for the common cold. However it is important to maintain optimal levels for Vitamin C as it is uptake in white blood cells
Do B vitamins help reduce the risk of CVD?
Do not need to take supplements, just maintain optimal levels within the diet.
What is the purpose of taking folic acid during pregnancy?
Folic acid fortification of food reduces the risk of neural tube defects in the first trimester of pregnancy?
What are phytosterols and the purpose of taking them?
Phytosterols are plant sterols and they have good evidence for reducing cholesterol
What is chondroitin sulfate taken for?
Improve joint health, but there is limited evidence behind it
Why is iron so tightly regulated in the body?
Pro-oxidant activity and therefore can cause damage within the body
Aside from haemoglobin, what else is iron incorporated into?
Myoglobin (found in muscle)
Cytochrome P450
Catalase
Peroxidase
Cell growth and differentiation
Describe the absorption and stores of iron within the body?
Only 10% of the dietary intake of iron is absorbed (roughly 1mg), must either be heme iron form or ferrous iron form to be absorbed from the intestinal tract into the epithelial cells of the villi. Some iron will not be absorbed into the bloodstream but will remain as ferritin in the epithelial cells.
When absorbed into the bloodstream it is transferred around the body where needed it (roughly 3-4mg) bound to transferrin.
Iron then is transferred to:
- Roughly 300-1000mg is stored in the liver as ferritin or haemosiderin (ideally want iron in this store and not free due to its pro-oxidant activity)
- Red blood cell precursors in the bone marrow, so that they can start transferring oxygen around the body. Circulating red blood cells store approximately 2500mg of iron.
Red blood cells are broken down in the spleen by reticulo-endothelial macrophages, transferred back to tranferrin bound iron.
The same amount of iron that is absorbed is lost daily through sweat, faeces, tissue shedding (GI epithelial cells shed cells every couple of days)
What are the dietary requirements for iron?
Dietary requirements for iron:
8.7mg for men 19 years and over and non-menstruating women over 50
14.8mg for women between 19-49 years
How is iron eliminated from the body?
1mg of iron is lost each day through:
Bilirubin from the liver
Skin
Reticulo-endothelial system from the spleen
What are the transporters that allow iron to enter the villi epithelial cells?
Heme carrier protein 1 (Heme iron)
Divalent metal transporter 1 (Ferrous iron)
What foods contain heme iron?
Red meat, fish, poultry
What foods contain non-haem iron?
Plant foods, lentils, beans, iron enriched, fortified foods
What substances increase and which decrease the absorption of iron?
Increase absorption- Vitamin C, red meat, organic acids
Decrease absorption- Soy, Phytates, Tannins, Calcium, Dietary fibre
Can ferric iron be absorbed into epithelial villi cells?
Ferric iron is the oxidised form of iron, it cannot enter epithelial cells until its in the reduced form (ferrous iron).
What Vitamin converts ferric iron to ferrous iron?
Vitamin C converts iron to its reduced form ferrous iron which allows it to be absorbed into the epithelial cells and potentially into the bloodstream.
What transporter (exporter) allows iron to enter the bloodstream from epithelial cells?
Ferroportin
What is anaemia and specifically iron deficiency anaemia?
Anaemia is when there is a decrease of healthy red blood cells in circulation. Red bloods cells become hypochromic and microcytic (small and pale). In iron deficient anaemia this is a clinical consequence of depleted iron levels in the body after stores have been depleted and there is a negative iron balance.
Is iron deficient anaemia common?
Most common form of anaemia worldwide. 80% of the world’s population are thought have low iron levels
Describe the structure of haemoglobin.
Red blood cells consist of haemoglobin. Each haemoglobin molecule is made up of four heme molecules. Each heme molecule contains a central iron atom which is essential for binding to oxygen. Therefore each haemoglobin molecule is capable of binding to four oxygen molecules, and then can transport oxygen around the body.
Which demographics are most likely to suffer with anaemia?
Teenage girls, Women of a childbearing age, during pregnancy, toddlers, older infants, premature babies and babies of a low birth weight
Which conditions may also have anaemia?
Kidney failure, Chronic malabsorption, GI disease
What are some of the clinical consequences of anaemia?
Pallor, tired or weak, poor work performance
Slow cognitive and social development
Decreased immunity
Heart failure if severe
Which Vitamin deficiency can occur alongside iron deficient anaemia?
Vitamin A which helps the absorption of iron
When are iron supplements given?
When iron deficient anaemia cannot be corrected by diet within a reasonable time
Clinical deficiency
What are some examples of supplemental iron and when do you take them?
Ferrous fumarate, Gluconate, Sulphate
Ferric iron
Dose spread possibly three times a day as the amount absorbed decreases with an increasing dose
What are some of the side effects of iron supplements?
GI- nausea, vomiting, diarrhoea
(Usually start with half a dose and titrate upwards)
What are examples of chronic iron toxicity diseases?
Thalassaemias
Haemochromatosis
What is Thalassaemias?
A group of inherited conditions that cause production of little to no haemoglobin, making them severely anaemic
Usually blood transfusions are required
What is Haemochromatosis?
A group of genetic conditions that cause the build up of iron in the body over a number of years and deposits of iron within tissues causing inflammation.
What are some of the treatments for chronic iron toxicity?
Iron chelators such as Desferrioxamine - complexed with ferric iron so it becomes unavailable and is eliminated from the body
Also Desferiprone (Thalassemia) and Deferisarox but these have more side effects
When does malabsorption occur?
Malabsorption occurs when one of the processes require for intestinal absorption is dysfunctional.
This could be:
Pancreatic secretion of digestive enzymes
Liver secretion of bile acids
Surface area of the intestine such as the villi
Brush border enzymes
What are some conditions that affect pancreatic secretion of enzymes?
Cystic fibrosis
Pancreatic insufficiency
Pancreatic cancer
What are some conditions that affect liver secretion of enzymes?
Gallstones
Liver disease
What are some conditions that affect surface area of the intestine?
Crohn’s disease
Coeliac disease
What are some conditions that affect brush border enzymes?
Lactose intolerant (75% of the world’s population)
What are the common symptoms of malabsorption syndrome?
Abdominal distension
Stunted growth
Diarrhoea
Most common cause of malabsorption?
Coeliac disease
What type of disease is Coeliac disease?
Auto-immune disease, attacks transglutaminase
Where is Coeliac disease most prevalent?
More common in Eastern and Northern Europe