10 Studies: Protein Intake and Strength Training After 50
Protein intake and strength training together are your dynamic duo for aging and loving it.
1) Protein was the determining factor when high or low carbohydrate intake did n’t have an impact on successful aging. “Successful” was determined by an integrated rating of social, physical, and mental performance.
2) In a 2018 review of literature of protein intake influence on aging researchers reported: “Currently recommended protein intake for aging adults may not be sufficient for muscle mass and strength maintenance.
To minimize the adverse health and environmental effects of excess animal protein consumption, incorporation of sustainably sourced plant proteins may be a promising strategy.”
I’ll link to previous conversations about the animal and plant protein dilemma.
3) Very high protein intake (≥1.2 g/kg/day) and high protein intake (≥1.0 g/kg/day) groups showed better lower limb physical functioning and walking speed (WS) performance in comparison to individuals who present relative low protein (<0.80 g/kg/day) intake.
4) Women below the higher RDA protein threshold had a significantly (p < 0.05) higher likelihood of having physical limitations (compared to higher RDA threshold). Additionally, they had significant differences in muscle mass.
In conclusion, the present study supports the RDA threshold of 0.8 g·kg-1 BW of proteins to prevent the loss of muscle mass and emphasizes the importance of the higher RDA threshold of at least 1.1 g·kg-1 BW to infer additional benefits on constructs of physical function.
This study also supports the role of protein intake for healthy aging, even in older adults meeting guidelines for physical activity. (Several studies point to protein needs increasing for sedentary and frail older adults).
5) Physical inactivity and inadequate nutrition (undereating or overeating the wrong things) accelerate age-related decrease in muscle mass and strength. The good news is that this status is subject to modification.
Physical activity/exercise guidelines need to make specific reference to resistance exercise and highlight the benefits of higher-intensity aerobic exercise training, alongside advocating older adults perform aerobic-based physical activity and household tasks (e.g., carrying groceries).
In terms of dietary recommendations, greater emphasis should be placed on optimal rather than minimum protein intake for older adults.
Guidelines that endorse a daily protein intake of 1.2-1.5 g/kg BM/day, which are levels 50-90% greater than the current protein Recommendation Dietary Allowance (0.8 g/kg BM/day), are likely to help preserve muscle mass and strength and are safe for healthy older adults.
Increasing the proportion of leucine contained in a given dose of protein, co-ingesting other nutrients (e.g., carbohydrate and fat or supplementation with n-3 polyunsaturated fatty acids) or being physically active prior to protein intake. These things are known to enhance muscle protein synthesis.
Increase Muscle Protein Synthesis:
- Exercise before protein
- Add carbohydrate and fat with protein (support absorption)
- Increase amount of leucine to about 2.3 mcg per serving of protein
What does 1.5 g/kg equal?
125 lbs = 57 kg
85 gm protein
28.5 gm protein
150 lbs = 68 kg
102 gm protein
34 grams per meal
6) Minerals may be important nutrients to prevent and/or treat sarcopenia (significant muscle loss). Particularly, magnesium, selenium, and calcium seem to be most promising.
7) An increasing body of experimental studies on skeletal muscle protein metabolism as well as epidemiological data suggest that protein requirements with aging might be greater than many current dietary recommendations.
Studies that compared muscle protein synthetic (MPS) responses to protein ingestion in young and old adults suggest that a higher relative protein intake is required to maximally stimulate skeletal muscle MPS in the aged oldest old (85+).
Regular physical activity may preserve and even enhance the responsiveness of aging skeletal muscle to protein intake, until very advanced age. Message? Keep exercising in order to keep protein synthesis optimal and stay youthful.
8) Studies investigated a total of 50,284 older adults from three different continents between 2006 and 2018. Four cross-sectional studies were included in the meta-analyses. The results demonstrated that a high protein intake was negatively associated with frailty status in older adults.
A distribution of protein intake spread evening over the main meals is better associated with gait speed than relative protein intake – aka it is NOT about how much per day but how much at every meal.
The study found frequent consumption of meals containing at least 30 g of protein was associated with greater lean mass and lower-limb muscle strength in middle-aged and older adults. Read: greater lean mass = lower body fat.
9) Another study found that more frequent consumption of meals containing between 30 and 45 g protein/meal produced the greatest association with leg lean mass and strength. Thus, the consumption of 1-2 daily meals with protein content from 30 to 45 g may be an important strategy for increasing and/or maintaining lean body mass and muscle strength with aging.
10) Moderate to Vigorous Physical Activity (MVPA) and frequency of protein consumption of ⩾30 g of protein per meal were independently associated with lower extremity lean mass and strength.
Study subjects had protein intake of at least 2 meals a day of 30 + grams of protein.
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