Abbott Nutrition Study: Older Women Gain Greater Muscle Benefits From Protein Plus HMB

Why It Matters

The enhanced MPS response in older women indicates that HMB could be a key supplement to counteract anabolic resistance, improving muscle health and reducing fall risk. This insight may shape product development and clinical guidelines for senior nutrition.

Key Takeaways

• 3 g HMB with 40 g whey boosts MPS in older women
• No extra MPS benefit observed in older men with HMB
• HMB prolongs suppression of muscle‑protein breakdown in both sexes
• Randomized double‑blind crossover trial with 24 adults aged 65‑75
• Results highlight need for larger sex‑stratified nutrition studies

Pulse Analysis

Aging muscle faces "anabolic resistance," meaning older bodies need more protein to trigger the same muscle‑protein synthesis (MPS) response seen in younger adults. Conventional whey shakes help, but researchers have long explored adjuncts like β‑hydroxy‑β‑methylbutyrate (HMB), a leucine metabolite that can activate mTOR pathways and curb protein breakdown. Understanding how HMB interacts with high‑dose protein is crucial for nutritionists aiming to preserve strength, mobility, and overall healthspan in seniors.

In a tightly controlled study, 24 participants aged 65‑75 consumed either 40 g whey alone or the same whey dose plus 3 g HMB in a randomized, double‑blind crossover design. Muscle biopsies and stable‑isotope tracing revealed that while both groups experienced elevated MPS, only older women showed a statistically significant extra boost from HMB. Men’s MPS response remained unchanged, though HMB did extend the suppression of muscle‑protein breakdown (MPB) for both sexes. These findings suggest a sex‑specific anabolic advantage that may stem from alternative signaling routes beyond mTOR, such as phospholipase D2 activation.

For the supplement industry, the data provide mechanistic backing for products that pair whey with HMB, especially those targeting female seniors at heightened fall risk. Clinicians may consider recommending HMB‑enhanced protein shakes as part of a broader sarcopenia‑prevention strategy. However, the modest sample size and exploratory nature of the sex analysis underscore the need for larger, stratified trials before definitive guidelines can be issued. Future research should explore dosage optimization, long‑term functional outcomes, and the interplay with resistance training.