Lec 5: Nutrition and Healthy Aging Flashcards
Percent of population 65 years and older from 2012 to 2050 and 3 reasons
11% in 2012, projected to be 22% in 2050
-advancements in healthcare/medicine
-lower fertility rates
-increased life span
What is sarcopenia
Age-related continuous decline in muscle mass, quality and strength
*Loss of strength, size and function of muscles
-Characterized by overall decreases in size and number of skeletal muscle fibers, mostly type 2/fast-twitch fibers, and a marked infiltration of fibrous and adipose tissue into the skeletal muscle
-Men <30kg handgrip strength, women <20kg
Why is sarcopenia an issue for public and personal health?
-The loss of muscle mass and strength with age will affect 250 million people worldwide by 2050.
-$18.5 billion (1.5% of total U.S. health care expenditure in 2000- the most)
*affect a lot of people, cost more for health care
Healthspan vs lifepsan
Healthspan= amount of time an individual spends in life in a state of good health
Lifespan= number of years in an individuals life
Lifestyle behaviours that influence health (6)
- Sleeping regularly and adequately
- Eating well-balanced meals regularly (including breakfast)
- Engaging in physical activity regularly
- Not smoking
- Not using alcohol or using it in moderation
- Maintaining healthy body weight
What matters most? Health span or life span?
Health span! and it can be modified…
biologically start losing strength/muscle at 30 (without PA), measurable at 40
*graph- linear decline without exercise and eating healthy to disability threshold, with interventions line stays straight right up until the end of lifespan
How much protein should i eat?
In Canada and US RDA= 0.8g protein/kg/day, average daily intake level sufficient to meet nutrient requirement of nearly all (98%) healthy individuals over 19 years
*RDA is designed to prevent deficiency, it is not the optiomal dose!
Older Adults: Anabolic Resistance
Anabolic resistance describes the reduced rise of muscle protein synthesis to the ingestion of protein/amino acids
-it is one factor contributing to loss of muscle mass
How to optimize protein nutrition in older adults?
Protein intake RDA= 75kg x 0.8 = 60g protein (not a lot)
BUT older adults require more protein to maximally stimulate muscle in a single meal (~0.4g/kg)
-multiple body mass (kg) by 0.4
Rates of muscle protein synthesis determine the size of human muscle mass (older people need more protein to stimulate more synthesis and to match younger population)
*Max MPS= 0.4-0.6g/kg
Protein intake in older adults is skewed (trends in meals)
Breakfast- 0.1g/kg
Lunch- 0.35g/kg
Dinner- 0.8g/kg (past 0.6=excreted in urine)
Snack- 0.2g/kg
Over max MPS= excreted
*protein intake not optimal at each meal, only at dinner, not meeting sufficient intake
Needs to be balanced and increased
Middle aged adults balanced vs skewed protein intake
90g (1.2g/kg/d) of protein in a mixed macronutrient meal
Balanced= 30g at each meal
Skewed= 10g breakfast, 15g lunch, 30g dinner
Balanced protein intake enhances 24h MPS in middle aged adults
*maximize turnover effects in the muscle
Revising Protein Intake (old vs. new calculation)
Old calculation:
-75kg x 0.8 per day= 60g
-3 meals= 10g (B), 20g (L), 30g (D)
*0.8g/kg/day
New calculation:
-75g x 0.4 per meal (1.2 per day)= 90g
-3 meals= 30g (B), 30g (L), 30g (D)
*1.2g/kg/day
Older adults protein intake and timing effect on MPS
Balanced protein intake does not alter skeletal MPS in older adults
-increasing protein (2 RDA vs 1 RDA) and distributing it evenly/balanced through 4 meals in a day= decreased risk of sarcopenia
*Increased protein intake= less loss of lean mass over 3-year period (quintile 5 vs. 1= increased amount of muscle, less muscle loss)
Recent protein recommendations (European)
Current= 0.8 RDA 19+ years
New >65=
-1.0-1.2g/kg minimum protein intake for healthy people
-1.2-1.5g/g for acute or chronic disease
-up to 2.0g/kg for severe illness or injury, or marked malnutrition
Oral Nutritional Supplements (ONS)
-Dysphagia associated with aging (difficulty swallowing)
-Older women may suffer from malnutrition
-Increased nutrition and caloric intake via ONS is often used, particularly in hospital settings
-Older people scared of choking with taking high amounts of protein (foods high in protein)
Is higher protein intake detrimental for renal function in healthy adults?
NO
-FAO/WHO reporting says no data links higher protein diets to renal disease, protein content of diet not related to progressive decline in kidney function with age
Omega-3 fatty acid intake and muscle anabolism
Meta-analyses show omega-3 fatty acid supplements at more than 2g/day may contribute to muscle mass gain and improve walking speed
Omega-3 fatty acid intake and MPS
Infusion of omega-3’s with amino acids increases MPS
Physical inactivity in middle aged and older adults results in
-After 60 years, if you break a bone/have an injury it is harder to recover, and even more important to recover and regain muscle
-Loss of muscle= increase in circulating glucose levels= diabetes
Muscle mass ~0.5-1.0%/yr
Muscle strength ~1-2%/yr
Physical inactivity and MPS
2 weeks of acute physical inactivity (<1000 steps per day) reduces rates of MPS in older adults
Essential amino acids and MPS
Essential a.a. partially protect against declines in MPS
-Collagen= not as effective for MPS, more of a waste of money
-Whey= helps muscle recover more, more MPS
Physical activity positive health implications- muscle and fat mass
Staying physically active throughout life has major positive health implications
-increasing step count (and maintaining high step count) can largely maintain muscle mass and decrease fat mass
-Young= more fat-free mass
-Old sedentary ~3000 steps/day and PA >3METS ~22mins/day= much more fat fass than FFM
-Old active ~12,000 steps/day and PA >3METS ~130mins/day= maintain muscle mass and keep fat mass less
Resistance exercise in older adults
-resistance training paired with protein intake stimulates muscle growth even in older adults
Aerobic exercise in older adults
-also very important for improving fitness levels and other benefits (heart health, less risk of disease and all-cause mortality)
