Familial Chylomicronemia Syndrome (FCS)
Very-low-fat medical nutrition therapy for a rare genetic lipid disorder.
Very-low-fat medical nutrition therapy for a rare genetic lipid disorder.
Familial chylomicronemia syndrome (FCS) is a rare inherited disorder in which lipoprotein lipase, the enzyme that clears dietary fat from the bloodstream, is missing or inactive. Chylomicrons, the particles that carry the fat absorbed from a meal, accumulate and push triglycerides to levels that can trigger acute pancreatitis. This is not high cholesterol with a bigger number: medications that lower LDL do little here, and a strict restriction of long-chain fat, typically in the range of 15 to 20 g per day and set individually by the treating team, is the primary therapy. Medium-chain triglycerides (MCT) are absorbed directly through the portal vein without forming chylomicrons, so they provide energy that does not count toward that ceiling. Our dietitians build plans that keep the two fat totals apart and maintain adequate energy, protein, essential fatty acids and fat-soluble vitamins under a restriction this severe.
Clinical Focus
Keeping long-chain fat within the individual daily ceiling, typically 15 to 20 g, to lower triglycerides and reduce the risk of acute pancreatitis.
Separating medium-chain triglyceride (MCT) fat, which forms no chylomicrons, from the fat that counts toward the limit, so every plan shows both totals.
Protecting nutritional adequacy under severe restriction: energy, protein, essential fatty acids and the fat-soluble vitamins A, D, E and K.
Coordinating with the treating lipid clinic and adjusting the plan to fasting triglyceride levels and the clinical course.
Managing the situations that break a very-low-fat pattern: restaurants, travel, alcohol and sudden-onset symptoms.
Key Points
Every gram of fat in a dish is traced to its ingredient, so the plan reports counted (long-chain) fat and MCT fat as two separate numbers rather than one estimate.
Simple sugars and alcohol raise triglycerides independently of fat and are limited alongside it.
Reading labels for hidden fat in baked goods, sauces, dressings and processed foods is a core skill taught from the first visit.
Complex carbohydrates, lean protein, fruit, vegetables and fat-free dairy form the base of the plan, with MCT oil as the main source of added fat where tolerated.
Supplementation of fat-soluble vitamins and essential fatty acids is assessed individually rather than assumed.