Lipoprotein changes when a reported diet is tested in distance runners.

Area of Science:

• Exercise Physiology
• Nutritional Biochemistry
• Cardiovascular Health

Background:

• Distance runners typically consume higher calorie and carbohydrate intakes than sedentary individuals.
• Previous diet records suggested a link between runner diets and serum lipid profiles.
• The specific impact of such diets on serum lipids and lipoproteins in active individuals requires detailed examination.

Purpose of the Study:

• To investigate the effects of a defined high-carbohydrate diet on serum lipids and lipoproteins in male distance runners.
• To quantify changes in low-density lipoprotein cholesterol, high-density lipoprotein (HDL) cholesterol, and associated apolipoproteins.

Main Methods:

• Ten male runners participated in a 21-day study involving a defined diet (53% carbohydrates, 32% fat) and daily 16 km running.
• Serum lipid and lipoprotein profiles were analyzed before and during the dietary intervention.
• Measurements included low-density lipoprotein cholesterol, high-density lipoprotein (HDL) cholesterol, HDL2 cholesterol, and apolipoprotein A-1.

Main Results:

• A significant decrease in low-density lipoprotein cholesterol was observed during the defined diet period (p < 0.01).
• High-density lipoprotein (HDL) cholesterol levels decreased significantly (p < 0.001), primarily due to a reduction in HDL2 cholesterol (p < 0.01).
• These alterations in HDL cholesterol were associated with decreased levels of apolipoprotein A-1.

Conclusions:

• The high-carbohydrate diet induced significant and unexpected reductions in HDL cholesterol and apolipoprotein A-1 in male runners.
• The magnitude of these lipoprotein changes suggests that previously recorded diet diaries may be unreliable or that other factors influence lipid metabolism in runners.
• Further research is needed to elucidate the complex interplay between diet, exercise, and lipoprotein metabolism in athletes.