Effect of Dietary Saturated Fat on the Production of Chylomicra Enriched inSatuirated Fat

摘要

Digested fat is absorbed in the small intestine, where cells produce lipoproteinparticles (chylomicra) that contain 300,000 to 500,000 triglyceride molecules. The composition of fatty acids consumed is reflected in the composition of fatty acids in the chylomicra. In some mammals (e.g., rats, monkeys, and cattle), dietary saturated fats lead to the production of plasma chylomicra enriched in saturated triglycerides (TG). When these chylomicra are cooled to < 20 deg C in vitro they form solid-phase TG cores that melt well above physiological temperatures ( > 45 deg C). Temperatures < 20 deg C have been documented in human extremities (e.g., fingers and toes) during occupational and recreational activities (e.g., scuba diving and open boat operation). Production of such chylomicra could have detrimental physiological consequences for humans during prolonged cold exposure. Such solidified core chylomicra (0.5-2.0 u in diameter) would be expected to persist, and could aggregate and impede blood flow through arterioles (20-50 um in diameter) and capillaries (2-8 um in diameter) to the fingers, toes, and essential organs (e.g lungs, heart, and brain). Thus, personnel conducting operations in cold environments after consuming a meal high in saturated fats could be at increased risk of impaired blood flow and non-freezing cold injury.