nutrition Flashcards
detecting inadequate nutrition
comparing dietary intakes with recommended intakes
adv- data available for large, representative samples
dis- individual requirements vary, poor absorption could contribute to nutrient deficiency despite adequate intake
biomarkers of nutritional status or symptoms of deficiency
advantage
- will reflect malabsorption
disadvantage
- biomarkers are not available for many nutrients
examining effects of supplementation
adv- any benefits will confirm appropriate treatment strategy
dis- requires symptom/biomarker
nutritional guidelines for older people
macronutrient guidelines as for younger adults
protein= 0.75g/kg/day
fat= saturated= 10% , polyunsaturated=6%, momnosaturated = 12%
total fat- <33%
fibre-18g/day
vitamin D
produced in skin from sun exposure so the status will differ naturally throughout the year
proportion of individuals with vitD below 25nmol/l is lowest in jul-sep and highest in jan-mar
limitations of surveys
surveys are completed in healthy, independent older people
those living in residential care with acute or chronic medical conditions or cognitive impairement are more vulnerable
may not be representative of all individuals as diet will differ depending on the needs of different individuals
vitamin D deficiency
common in older people
- facilitates calcium absorption
- deficiency casues bone softness and pain (rickets in children) and osteomalacia in adults
- can get from dietary intake
- can get endogenous prod in skin following sunshine exposure but lower in older people, those wihth darker skin and people who avoid sun
- vti D best in summer
vit D supplementation
meta analysis found
- no effect on muscle strength
- no effect om falls or fractures
- no effect on cognititon
- reduced cancer mortality by 15%
- no effect on mortality from other causes
- reduced risk of acute resp tract infection
studies are not well regulated
vitamin D and health outcomes
insuffiency is associated with
- osteomalacia
- osteoporosis
- falls
- frailty
- cancers
- cardiovascular disease
- poor cognitive function
anaemia
may contribute to declining physiological and cognitive ability
may result from reduction in erythropoisis by inflammation associated with chronic disease, malabsorption of b12, iron deficiency
iron deficiency
poor intake is a minor cause
malabsorption- atrophy of villi in small intestine
blood loss- gastrointestinal pathologies eg gastric cancers + stomach ulcers, infection with parasites, chronic use of non steroidal anti inflammatory drugs
vit b12 deficiency
mostly not driven by low intake
loss of gastric parietal cells accounts for 15-20% of cases of cobalamin deficiency- lack of intrinsic factor
most other cases due to atrophy of cells within the gastric mucosa, ileum or bacterial overgrowth in SI
protein energy malnutrition
protein deficiency
- suppressed immunity
- slow wound healing
- loss of muscle mass
sarcopenia
low protein intake associated with frailty and sarcopenia
some recommend 1-1.2g/day protein in healthy adults
from studies- protein supplementation of 12-32g per day did not benefit physical function according to meta analysis although there were benefits in some stidies
protein supplementation enhances training related gains
nutrition and frailty
frailty was associated with low energy intake (<21kcal/kg) OR 1.24
people with low protein, vit d,c and e and folate intake have sig increased risk of beinf frail
social contributors to malnutrition
14% of UK residents >65yo were malnourished
1in 6 at risk of poverty in EU
social isolation- 1in 7 live alone- major contributor to weight loss
malnutrition increases risk of pressure ulcers- reducing immunity and healing
poor health associated with risk of malnutrition
malnutrition prevention strategies
institutions
-food quality- variety, easy to eat, appropriate portion size
- environment- social context, assistance or modified utensils if needed
community
- community meals/lunch clubs or meals on wheels can prolong independent living
calorific restriction
can it extend lifespan?
some metabolic and endocrinological responses
- redcued body fat content
- decreased inflammation
- reduced ROS (increased repair)
- changed activity of nutrient signalling pathways- decreased glucose/insulin signalling, decreased IGF-1 activity
- improved proteostasos- upregulation of chaperone proteins
altered apoptosis
- increased apoptosis of rapidly dividing cells eg skin
- reduced apoptosis of neuron and liver cells
hormesis theory
- stress promotes survival response which attenuates ageing
antioxidants + ageing
delaying ageing
ROS formed at mitocondiral complexes I and II of ETC
may react with and damage mtDNA proteins (cross linking, glycation) and membranes (lipid perioxidtion)
dietary antioxidants - vit ACE and selenium
antioxidant supplementation doesnt reduce mortality
