Whey Protein Builds Muscle Strength in Older Adults with Weight Training

randomized-controlled-trial PMID: 33564844

Whey Protein Builds Muscle Strength in Older Adults with Weight Training

Quick Summary: This study tested if whey protein supplements help older adults (over 65) keep or grow their muscle size, strength, and daily function over one year. Whey protein alone didn't make a difference compared to a carb-only supplement, but pairing it with heavy weight training boosted muscle size and strength. Light exercise with whey helped strength a bit but not muscle growth.

What The Research Found

Researchers wanted to see if whey protein, taken alone or with exercise, could fight muscle loss that comes with aging. They measured thigh muscle size (using scans), leg strength (like how much force your knee can push), power, and real-life tasks like standing from a chair.

Key results in simple terms:
- Whey protein alone: No real changes in muscle size, strength, or function compared to just carbs. Collagen protein (another type) also didn't help.
- Whey with light exercise: This built some leg strength (about 14% better than whey alone) but didn't grow muscle size.
- Whey with heavy weight training: This was the winner—it grew thigh muscle by about 2 square centimeters more than whey alone, boosted pushing strength by 18-24% (depending on the test), and improved daily function like walking speed.

Overall, protein supplements by themselves aren't enough; you need to lift weights to see benefits.

Study Details

Who was studied: 208 healthy older adults over age 65 (average age 72, about half women) living independently in the community—no major health issues.
How long: One full year, with check-ins along the way; 184 people finished the study.
What they took: All groups got supplements twice a day. Whey group: 20 grams of whey protein plus 10 grams of carbs per dose (total 40 grams protein daily). Compared to carbs-only (30 grams carbs per dose) or collagen protein. Exercise groups did resistance training: light (3-5 days a week, like easy bodyweight moves) or heavy (3 days a week, using weights that challenge you).

What This Means For You

If you're an older adult worried about losing muscle (which can make daily activities harder and raise fall risk), this study shows whey protein shakes aren't a magic fix on their own. But if you combine them with heavy weight training—like squats or leg presses 3 times a week—you could build noticeable muscle and get stronger. Start with 40 grams of whey protein daily (split into two shakes) and talk to a doctor before lifting heavy. Even light exercise might help your strength for easier tasks, but for real muscle gains, go heavier. This could help you stay active and independent longer—aim for consistency to match these results.

Study Limitations

It focused on healthy seniors, so it might not apply if you have illnesses, frailty, or live in a care facility—those folks may need tailored advice.
The supplements included some carbs, so it's not pure protein effects; real shakes might vary.
Sticking to heavy workouts for a year is tough— the study notes more research is needed on how to make it easier for people to keep it up long-term.
One year is a solid test, but we don't know if benefits last beyond that or how it works for everyone.

Source: PubMed | Trial Registration: NCT02034760

Key Findings

In healthy adults over 65, whey protein supplementation alone (20 g protein +10 g carbohydrate twice daily) did not improve quadriceps cross-sectional area (qCSA), strength, or function compared to carbohydrate supplementation. However, combining whey with heavy resistance training (HRTW) increased qCSA (+1.68 cm² vs. WHEY), dynamic (+18.4 Nm) and isometric knee extensor strength (+23.9 Nm), and functional performance. Light-intensity training with whey (LITW) improved dynamic strength (+13.7 Nm vs. WHEY) but not muscle size.

Study Design

This 12-month randomized controlled trial (RCT) enrolled 208 healthy older adults (mean age 71.5 y; 54% female). Participants were assigned to one of five groups: carbohydrate-only (CARB), collagen protein (COLL), whey protein (WHEY), light-intensity resistance training + whey (LITW), or heavy resistance training + whey (HRTW). The primary outcome was qCSA change; secondary outcomes included strength, power, function, and body composition.

Dosage & Administration

All supplements were provided twice daily (total 40 g protein +20 g carbohydrate/day for protein groups; 60 g carbohydrate/day for CARB). Whey and collagen supplements contained 20 g protein +10 g carbohydrate per dose. Resistance training protocols were standardized: LITW (3–5 sessions/week) and HRTW (3 sessions/week).

Results & Efficacy

qCSA: HRTW increased qCSA vs. WHEY (+1.68 cm²; 95% CI: +0.41 to +2.95 cm²; P=0.03).
Dynamic strength: HRTW improved knee extensor strength by +18.4 Nm (95% CI: +10.1 to +26.6 Nm; P<0.0001) vs. WHEY.
Isometric strength: HRTW increased strength by +23.9 Nm (95% CI: +14.2 to +33.6 Nm; P<0.00001) vs. WHEY.
LITW: Improved dynamic strength (+13.7 Nm; 95% CI: +5.3 to +22.1 Nm; P=0.01) but not qCSA.
COLL and WHEY alone: No significant differences vs. CARB in any outcome.

Limitations

Population specificity: Participants were healthy, community-dwelling older adults; results may not apply to frail or clinical populations.
Compliance challenges: Long-term adherence to heavy resistance training (HRTW) was not assessed in detail, though critical for real-world application.
Supplement composition: Whey/collagen supplements included 10 g carbohydrate per dose, potentially confounding effects of protein alone.
Duration: 1 year is robust for RCTs, but longer-term effects on aging muscle remain unclear.

Clinical Relevance

For older adults, whey protein supplementation alone (40 g/day) is insufficient to enhance muscle mass or strength. Combining whey with heavy resistance training (3 sessions/week) is necessary to achieve measurable gains in muscle size and strength. Light-intensity training with whey may offer modest benefits for dynamic strength but not muscle hypertrophy. Clinicians should prioritize resistance exercise prescription alongside protein supplementation to optimize outcomes in aging populations. Future research should focus on strategies to improve adherence to heavy training regimens in long-term interventions.

Source: PubMed | Trial Registration: NCT02034760