Study under review: The effect of chronic soluble keratin supplementation in physically active individuals on body composition, blood parameters and cycling performance
Keratins are a class of fibrous proteins serving as the main structural constituent of feathers, horns, hooves, and hair. Historically, keratins have been considered a waste product from processing livestock to meat due to their indigestibility. However, a patented highly digestible (83% digestibility in vivo) keratin protein supplement has recently been developed that overcomes this limitation.
The patented keratin product is rich in the sulphur-containing amino acid cysteine (primarily as cysteic acid), which is important for the synthesis of glutathione and taurine in the body. One study in rats found that replacing 50% of dietary casein protein with this patented keratin product increased blood hematocrit and hemoglobin content, tended to improve lean to fat mass ratio, and increased liver taurine content. However, glutathione levels were not affected.
Taurine is the most abundant free amino acid in the body, and plays important roles in numerous essential biological processes, including muscle contraction and relaxation, lipid metabolism, and, potentially, muscle protein synthesis. Some research has found taurine supplementation to improve time to exhaustion and maximum workload in recreationally trained men, and other research has observed a reduction in exercise-induced muscle damage and exercise-induced oxidative stress.
Since keratin supplementation potentially has the ability to increase the glutathione and taurine levels in the body, it has been hypothesized that supplementation may improve exercise performance and enhance training adaptations. Additionally, since blood concentrations of erythrocytes and hemoglobin are significant limiting factors in oxygen transport during exercise, keratin’s ability to increase hematocrit and hemoglobin in rats may benefit endurance exercise performance as laid out in Figure 1. However, research examining the effects of keratin supplementation is scarce in animals and non-existent in humans.
If the above changes can be induced in humans, then keratin protein may be a cheap and effective protein source for people aiming to improve body composition and endurance performance. The study under review was the first to evaluate the effects of supplementation with the patented keratin product in endurance-trained men.
Keratins are fibrous proteins that make up hair, hooves, feathers, and horns. They have a low digestibility and are traditionally considered a waste product of animal processing plants. However, a patented and digestible keratin protein supplement has been made, which is rich in sulfur-containing amino acids that may benefit endurance exercise performance. The study under review was the first to evaluate the effects of keratin protein in humans, specifically endurance-trained men.
Other Articles in Issue #48 (October 2018)
Interview: Bill Willis, PhD
What the heck is HMGB1 and why care about it? In this interview, we pick the brain of Examine.com researcher Bill Willis about a recent paper he published on the matter, and get his insights on the research process and his opinion on the recent spate of scientific misconduct reports.
Mini: Vitamin D, dementia, and lipids: the ApoE connection
In this mini, we give you a quick summary of recent research examining how ApoE genotype affects the way blood lipids respond to swapping out dietary saturated fat for carbs.
Which diet’s best for weight and metabolic risk factors in people with type 2 diabetes?
There's quite a bit that's known about how diets impact diabetes. What's less well understood is how different diets compare. This network meta-analysis aimed to find out.
Paleo plus exercise: not the perfect match from the past?
There's little question that diet and exercise both help with type 2 diabetes. But the added benefits of exercise on top of the paleo diet is less well understood.
CoQ10 supplementation helps with one pole of bipolar disorder
There's reason to believe that coenzyme Q10 supplementation can impact on unipolar depression. This trial looked at whether it could also improve depression in people with bipolar disorder when added to standard treatment.
Elderly people at risk for dementia may benefit from vitamin D supplementation
Not everyone with mild cognitive impairment (MCI) proceeds progresses to dementia, but the majority do. Can vitamin D supplementation help with cognition in people with MCI?
Can alpha lipoic acid help manage metabolic diseases?
We've previously covered a meta-analysis looking at ALA's impact on weight. But how much of an impact does it make on cholesterol and glycemic control?