Plasma B-6 vitamer changes following a 50-km ultra-marathon

Area of Science:

• Biochemistry
• Human Physiology
• Nutritional Science

Background:

• Vitamin B-6 vitamers play crucial roles in metabolic processes.
• Extreme physical exertion can alter nutrient concentrations in the body.
• Understanding vitamin B-6 dynamics during prolonged exercise is important for athlete health.

Purpose of the Study:

• To measure plasma concentrations of vitamin B-6 vitamers (PLP, PL, PN, 4-PA) and related factors in athletes undertaking an ultramarathon.
• To investigate how extreme physical conditions affect plasma vitamin B-6 levels.
• To compare findings with previous research on shorter endurance events.

Main Methods:

• Blood samples collected from 11 ultramarathon runners pre-race, and 5 and 60 minutes post-race.
• High-performance liquid chromatography (HPLC) used to quantify plasma pyridoxal 5O-phosphate (PLP), pyridoxal (PL), pyridoxine (PN), and 4-pyridoxic acid (4-PA).
• Plasma glucose, albumin, lactate, alkaline phosphatase, hematocrit, and hemoglobin were also measured. Food and fluid intake were recorded.

Main Results:

• Plasma PLP concentration significantly decreased by 31% at 5 minutes post-race and 44% at 60 minutes post-race.
• Total vitamin B-6 (TB6) concentration showed a smaller decrease of 13.5 nmol/L from pre-race to 60 minutes post-race.
• Plasma PL increased by 25% post-race, while 4-PA increased initially then returned near pre-race levels.
• Observed PLP decrease is more substantial than reported in shorter endurance studies.

Conclusions:

• Ultramarathon running leads to a significant and substantial decrease in plasma PLP concentrations.
• The metabolic response of vitamin B-6 during extreme endurance exercise differs from that observed in shorter events.
• Further research is needed to elucidate the mechanisms behind these changes and their implications for athletes.