Exercising increases the presence
of free radicals that can damage tissues. Unaccustomed and high intensity
exercise causes muscle damage known as delayed-onset muscle damage that
involves protein degradation in the body. The damage occurs because of several
factors, including mechanical stress, calcium accumulation, and oxidative
Fermented milk has several
benefits including prolonged lifespan, antihypertensive effects,
anti-tumorigenic effects, and immune system regulation
. Some types of fermented
milk also possess anti-inflammatory and antioxidant properties.
In one of their earlier studies,
Masayo Iwasa and colleagues have shown that Lactobacillus
-fermented milk prevents muscle damage induced by acute exercise
in experimental animals, suggesting that fermented milk may prevent the
impairment of glucose metabolism associated with muscle damage.
So, this time they conducted a
trial to investigate the effect of fermented milk supplementation on glucose
metabolism associated with muscle damage after acute exercise in humans.
Eighteen healthy young men aged
20 to 22 years who were not habituated to a regular exercise regimen
participated in this study. They participated in three trials of the study:
rest with placebo intake (rest), exercise with placebo intake (placebo), and
exercise with fermented milk intake (fermented milk).
High intensity exercise included
resistance exercise consisting of five sets of leg and bench presses at 70-100
percent 12 repetition maximum. Examination beverage (fermented milk or placebo)
was taken before and after exercise. On the following day, respiratory
metabolic performance, blood collection, and muscle soreness were assessed.
The findings were-
ē Muscle soreness
significantly suppressed by the consumption of fermented milk compared with
ē Serum creatine phosphokinase
was significantly increased by exercise, but this increase showed a tendency of
suppression after the consumption of fermented milk.
decreased the respiratory quotient, although this decrease was negated by the
consumption of fermented milk. [Respiratory quotient (RQ) is a measurement of
the ratio between oxygen intakes and carbon dioxide exhaled by an individual
Exercise significantly reduced
the absorption capacity of serum oxygen radical, although this reduction was
not observed with the consumption of fermented milk.
These results indicate that
dietary fermented milk improves the impairment of glucose metabolism associated
with exercise-induced muscle damage in healthy people.
'Previously, (studies have shown
that) consumption of milk (unfermented) partially attenuates the muscle damage;
therefore, the placebo trial, which used unfermented milk, may have also
suppressed muscle damage to some extent. However, our results showed that
fermented milk is more effective than milk,'
says Wataru Aoi, one of the study
'The present study suggests that small digested
peptides in fermented milk may contribute to increasing the level of
antioxidants in muscle. In future studies, we will attempt to detect the
specific small peptides present after the consumption of fermented milk,' they