Nutrition and Aging Flashcards
What are macronutrients?
Nutrients that must be sinus especially daily and in relatively large amounts
What are micronutrients?
Nutrients that must be consumed in relatively small amounts
What are examples of macronutrients?
Proteins, carbohydrates and lipids
What are examples of micronutrients?
Vitamins and minerals
What are essential nutrients?
Nutrients that must be obtained from the diet
What are non essential nutrients?
Nutrients that are not required in the diet because they are produced by biochemical processes of the body
What is a nutrient?
Any substance in food that is used by the body to promote normal growth, maintenance and repair
When does the absorptive state occur?
The time of eating, digesting and absorbing nutrients
When does the post-absorptive state occur?
Time between meals
What are the characteristics of the absorptive state?
- lasts 4 hours after a meal
- concentrations of nutrients increase as they are absorbed from the gut
What are the characteristics of the post-absorptive state?
- body relies on stores of nutrients
- body woks to maintain homeostatic levels of nutrients
What are the three types of carbohydrates?
- monosaccharides: glucose, fructose, galactose
- disaccharides: sucrose, lactose, maltose
- polysaccharides: dextrose, cellulose, starch, glycogen
What is the major hormone during the absorptive state?
Insulin
What is the major hormone during the post-absorptive state?
Glucagon
Why is regulation of blood glucose so important?
- low blood sugar levels compromise normal brain function
- high blood sugar levels damage blood vessels and nerves
Diabetes mellitus type 1
- inability to produce sufficient insulin
- 10% of diabetes cases
- treated by self-monitoring of glucose and artificially injected insulin
Diabetes mellitus type 2
- decreased responsiveness of cells to insulin
- 90% of diabetes
- risk factors: age, obesity, genes
- treatment: changes in diet and exercise
What is BMI?
Kg per m^2 = weight/height^2
What are overweight and obese BMIs?
Overweight: 25
Obese: 30+
What are the three things that causes the body to grow?
- hypertrophy
- hyperplasia
- extracellular Matrix
What is hyperplasia?
Division of cells
What is hypertrophy?
Growth of cells
What are some key changes in rates of height growth?
- post natal decline
- pubertal peak
Why is there a dip in height before and after birth?
Challenges before and after birth
What is the challenge before birth?
Fetus outgrows the placenta
What is the challenge to growth after birth?
Change in environment = biggest homeostatic challenge that the body faces
What hormone is essential for bone and muscle growth?
Thyroid hormone
What hormones are important for fetal growth?
- GH relatively unimportant
- insulin and insulin like growth factors (IGFs) are more important
What does GH do?
- acts as an anabolic hormone
- promotes hyperplasia and hypertrophy
What are the key targets of GH?
Muscle and bone
What stops growth at the end of puberty?
Epiphyseal plate closure by sex steroid hormone
What is senescence?
The process by which cells stop dividing and enter state of permanent growth arrest
What is Hayflick’s limit?
All cells have a finite capacity to did die (40-60 times)
What is a telomere?
GGGTTA repeated on chromosome ends
What does a telomere do?
Generates stability at ends of chromosomes
What happens to telomeres and how are they repaired?
- telomeres are lost during replication
- telomerase repaired lost telomeres (low in somatic cells’
What are free radicals?
By products of oxidative phosphorylation
- OH, H2O2
What are some effects of senescence?
- decreases protein synthesis capacity
- decreases immune function
- decreases hormone production
- decreases muscle mass
- decreases bone density
- decreases respiratory function
What causes menopause?
Decline of gonadal oestrogen due to loss of follicles
What are some symptoms of menopause?
- decreased bone density and muscle mass
- increased body fat
What is the treatment for menopause?
HRT: combined estrogen progesterone
What is the risk of HRT for menopause?
Increased risk of breast cancer
