Beef protein, muscle mass and iron in older male triathletes
What it found
In older male triathletes, a daily beef protein drink preserved thigh muscle thickness and raised ferritin levels over 10 weeks.
Whey protein did not show these effects.
What they found
Studies in people
Thigh muscle thickness
The beef group kept their thigh muscle thickness about the same, going from 34.1 to 35.5 mm. Both the whey and carbohydrate groups lost muscle thickness in that area.
Ferritin levels rose
Ferritin, a marker of stored iron, went up in the beef group from 117 to 150.5 ng/mL. It did not change in the whey or carbohydrate groups. The rise in the beef group was larger than in the other two.
Body weight dropped
Only the beef group lost body weight over the 10 weeks. The authors say this was mostly due to losing fat rather than muscle.
Fitness stayed the same
Peak oxygen use during exercise did not change in any of the three groups. Other blood markers also stayed the same across all groups.
What the authors conclude
- They suggest that drinking hydrolyzed beef protein after training or before breakfast helps preserve thigh muscle in older male triathletes.
- They note that the beef drink improved iron storage markers compared to whey or carbohydrate drinks.
- They call for larger studies to confirm whether beef protein can reliably maintain iron stores in endurance athletes.
How it was done
Endurance athletes often lose iron through sweat and gut bleeding, which can hurt performance. The authors wanted to see if beef protein could protect muscle and improve iron stores better than whey or carbohydrate drinks.
Twenty-four male triathletes aged 35 to 60 were split into three groups of eight. For 10 weeks, each group drank 20 g of either beef protein, whey protein, or carbohydrate powder mixed with water once a day. Researchers measured body weight, thigh muscle thickness, fitness, and blood markers before and after.
What it can’t tell you
- Only 8 people were in each group, so the results might look different in a larger trial.
- The beef group started with slightly lower ferritin levels, which may have made it easier for those numbers to rise.
- All participants were older male triathletes, so the findings may not apply to women, younger people, or those who do not train intensely.
Who paid
- Authors work at
- University of Greenwich, United Kingdom; Texas Tech University Health Sciences Center, USA
The paper
- Title
- Effects of Supplementation with Beef or Whey Protein Versus Carbohydrate in Master Triathletes
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Naclerio F, Seijo M, Larumbe-Zabala E, et al (2017). Effects of Supplementation with Beef or Whey Protein Versus Carbohydrate in Master Triathletes. Journal of the American College of Nutrition. doi:10.1080/07315724.2017.1335248Free full textPubMed 28910233DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error