Nutrition for Health Aging

Question 1

Daily regulation of protein balance

Answer 1

over the day synthesis = degradation
* during fasting synthesis < degradation
* postprandial Synthesis > degradation

Question 2

What is needed for protein synthesis versus degradation?

Answer 2

• synthesis occurs with increased AA and insulin
• degradation occurs with decreased or stable AA and decreased insulin

Question 3

Association of protein anabolism with insulin sensitivity

Answer 3

Whole-body protein anabolism is correlated with insulin sensitivity so the more insulin sensitive we are the more anabolic we are
* Measured through CLAMP method which is the golden standard to measure in body in real time what is happening with metabolism. 2 needles with one infusing insulin and the second glucose or AA and can adjust the movement of substrates into blood so can create environment that looks like post prandial state

Question 4

Findings of anabolic resistance in aging

Answer 4

In response to infused insulin there was lower protein balance and lower muscle protein synthesis but normalized with supraphysiological hyperinsulinemia and hyperaminoacidemia so they have higher threshold requirements
* oral low dose of AA saw lesser muscle protein synthesis but normalization with higher dose (25-30 g protein)

Question 5

Protein quality for protein synthesis

Answer 5

Leucine is most potent stimulator and acts as an intracellular signal to stimulate mRNA translation and protein elongation through mTOR.
* Overall essential amino acids predominantly stimulate protein synthesis

Question 6

Animal versus plant proteins for protein synthesis

Answer 6

Acute (postprandial) studies on the stimulation of muscle protein synthesis (MPS) by different protein sources (resting conditions)
* In young men: whey > soy > casein
* In older adults: beef > soy; up to 40 g soy protein failed to induce MPS
* In older men: casein > wheat; 60 g wheat protein = 35 g casein

AA and Leu content (relative and absolute) and digestibility are important to consider

Question 7

finding from longitudinal cohort studies on animal versus plant proteins

Answer 7

• Health ABC study: higher total and animal protein intake related to lesser loss in lean and muscle mass over 3 years
• Framingham Offspring study: higher total and animal protein intake related to lesser loss in handgrip strength over 6 years
• But, consumption of plant protein is low (≅30-40%) in US and Canada: interpret with caution
• In n=2726 Chinese older adults, highest vs. lowest quartile of plant protein intake lost less muscle mass over 4 years indicates that total protein was driver here and availability of EAA

Question 8

What physiological processes are associated with great loss of lean muscle and strength in older adults

Answer 8

anabolic resistance, lower anabolic stimuli and presence of catabolic stimuli
* more amino acids needed to stimulate post-prandial myofibril protein synthesis

Question 9

Protein reccomendations for older adults

Answer 9

• high quality protein
• 1.2 g/kg/d for maintenance, higher for gain
• ~30 g per meal to stimulate protein synthesis

Question 10

What is associated with vitamin D deficiency?

Answer 10

associated with muscle weakness and decreased function which may be related to vitamin D receptor (VDR)
* expressed in muscle fibre, decreases with age
* knockout VDR models showed decreased muscle fibre size

Question 11

What has research shown with vitamin D and leucine intake?

Answer 11

• In sarcopenic older adults, vitamin D and leucine intake have shown enhanced appendicular muscle mass (aMM) and improved lower-extremity function.
• Vitamin D suppl. showed protective effect against sarcopenia and saw increases in muscle strength in postmenopausal women (still lose muscle but intervention less so)
• meta-analysis has shown vitD suppl. has significant positive effect on global muscle strength.
• Vitamin D suppl. more effective for patients with 25-hydroxyvitamin D level <30 nmol/L and aged 65 or older

Question 12

Findings for dairy products as a food to enhance body composition

Answer 12

• Positive association of dairy intake with appendicular muscle mass in elderly women (>80years) - Elderly women with mean dairy intake of 2.8 servings/day had significantly better skeletal muscle mass compared with those with mean dairy intake of 0.9 servings/day.
• Improved appendicular skeletal muscle mass, strength, SPPB and attenuate the loss of muscle strength in men and women >60 years (ricotta cheese)

Question 13

What is contributing to more osteoporosis being seen in older adults and at younger ages?

Answer 13

teens not particpating in as much bone building activities and this the peak time to build the bone
* As you get older bone building activities are important to prevent bone loss over time especially women during menopause with the loss of estrogen

Question 14

What is also important for LBM besides protein intake?

Answer 14

Resistance training is critical for retaining muscle
* never too late to start and can see effects in as little as 8 weeks
* low tech, low-cost equipment - can use milk jug or soup cans
* safe for older adults
* goal is not to ‘bulk-up’ but to build and maintain enough muscle mass to avoid functional impairment

Question 15

The World Health Organization’s life-course model of non-communicable disease.

Answer 15

Risk positively accumulates throughout the life-course, and disease become Manifest in later life

Question 16

What are bluezones?

Answer 16

• 5 zones around the world with an older population but are healthy

Question 17

What are common factors seen in blue zones?

Answer 17

• Plant-based, nutrient dense diet
• Active living/ more movement
• Avoiding excess
• Social interaction and have lots of support
• Value rest/relaxation
• Purpose in life

Question 18

Top 30 causes of death categories ranked

Answer 18

1. red: behavioural
2. blue: environmental
3. green metbaolic

Lots of these are dietary risks

also childhood undernutrition and suboptimal breastfeeding

Question 19

Most studied dietary pattern

Answer 19

mediterranean diet based on typical diet in the Mediterranean region in the 1950’s (much different now) showed low rate of CHD and small but significant reduced risk for all-cause mortality (from meta analysis)
* higher intake of legumes, whole grains, fruit, vegetables, fish, MUFA (olive oil)
* moderate alcohol intake
* lower intake of meat, eggs, dairy

Question 20

When is micronutrient supplementation beneficial?

Answer 20

• Can improve health outcomes and reduces risk of mortality if deficient
• Effective in preventing deficiencies and improving health outcomes in high risk populations based on life stage (vitamin D in older adults, folate and iron during pregnancy etc.)

Question 21

multi-vitamin use and risk of mortality

Answer 21

systematic review and meta-analysis in ~90,000 young to older adults showed there was NO association of MVM with CVD and cancer which are the major killers in NA

Question 22

Individual Micronutrient Supplementation and Risk of Mortality

Answer 22

Systematic review and meta-analysis in ~290,000 young to older adults (mean 37 to
69 yrs) showed:
No association with all-cause mortality: calcium, selenium, zinc magnesium vitamin C, vitamin D, vitamin E (except CVD mortality), folate (except cancer mortality)
Increased risk of mortality if high-dose: vitamin A (≥25,000 IU) and beta-carotene (≥30mg)

Question 23

What is CR?

Answer 23

Calorie restriction
* consuming lower energy (with an adequate nutrient intake to prevent deficiency) to extend lifespan
* Adapt to energy balance at lower energy intake with lower BW, BMR and TEE

Question 24

What is lower energy?

Answer 24

Difficult to define in humans: what is normal body weight?
* in animals it is easier to define: less than what is required to maintain ‘normal’ body weight

Question 25

Effects of CR in Animal Models

Answer 25

Liver longer and healthier
* Effect on lifespan: retards aging, extends median and maximal lifespan
* Impacts on health: decreased the rates of aging-related diseases/conditions (cancer, heart disease, stroke, hypertension, insulin resistant)

Question 26

Proposed mechanisms for how calorie restriction might extend lifespan

Answer 26

• lessen oxidative damage by reducing metabolism (taking in less good uses less oxygen)
• alterations in cell signaling (nutrient sensing)
• lowers fat mass and inflammation
• modifies gene expression
• decreases risk of CVD and cancer, increases insulin sensitivty

Question 27

Findings from CR in short lived species

Answer 27

Rats fed less energy (one third less than normal level) lived longer: 800 days versus 500 days
* Since then it has been established that in short-lived species (rats, mice, dogs, etc): 30-60% reduction in energy intake initiated in early life increases mean and maximum lifespan

First studies in 1930s by Clive McCay (Cornell University)

Question 28

UW findings for CR in long lived species

Answer 28

Fed rhesus monkeys semi-purified diets of either ad libitum (micronutrients 100% per 100g) or calorie restriction (micronutrients 130% per 100g) at age 7-14 years
* calorie increased survival (not a huge effect but still present)
* delay in age related morbidities
* mortality did not change however

Question 29

NIA finding for CR in long lived species

Answer 29

Fed two age groups rhesus monkeys, young-onset (1-14 yrs) and old-onset (16-23 yrs), naturally sourced diets (ground food sources) of either fixed adequate intake (micronutrients 140% per 100g) or 30% less than adequate energy (micronutrients 140% per 100g).
* CR did not increase survival for either old-onset
* CR delayed onset of age-related co-morbidities for young-onset

Question 30

Why different results between the UW and NIA findings of CR in long lived species

Answer 30

• different age at start: no age onset showed life extension
• UW controls weighed more and had higher adiposity than NIA controls but no relationship between adiposity and mortality
• different diets with UW using processed food and NIA using real food

Question 31

Does Calorie Restriction in Animals Translate to Humans?

Answer 31

Limited practicality
* Lab animals are in a controlled environment so can humans living in the real-world maintain CR from young adulthood to end of life?
* There is a cost with CR: reduced TEE effecting living life (working, activities) which requires expenditure
* Quality of life: counting calories, ensuring adequate nutrients on low calories, lower activity; disordered eating?

Question 32

Useful Information from the Calorie Restriction Studies

Answer 32

• CR extends longevity if consuming a diet that promotes increased adiposity (use fat for energy)
• CR can prevent excess energy intake (maintain healthy body weight by balancing energy) intake and expenditure
• Diet quality matters - an unhealthy diet with adequate micronutrients to prevent deficiencies is not the same as a healthy diet