Christina T. Loguidice
Familial chylomicronemia syndrome (FCS), also known as familial lipoprotein lipase deficiency
and hyperlipoproteinemia type I
, is a rare hereditary disorder of lipoprotein metabolism resulting from the presence of LPL inhibitors or deficiencies in familial lipoprotein lipase (LPL) or apolipoprotein C-II. FCS prevents triglycerides from being cleared from the blood plasma, leading to extremely high concentrations of triglycerides and chylomicrons. Subsequently, patients may develop severe abdominal pain, hepatosplenomegaly, life-threatening pancreatitis, lipaemia retinalis, and eruptive xanthomas.
Because there is no clear diagnostic profile for FCS, the condition may go undetected or may be improperly diagnosed as hypertriglyceridemia during childhood. In some patients, the condition is only diagnosed when the pancreatitis becomes severe enough to require hospitalization  Once properly diagnosed, treatment focuses on reducing circulating triglycerides and chylomicrons by adhering to a very strict low-fat diet. Currently, no pharmacotherapies are approved in the United States to manage FCS.
Rare Disease Report
had the opportunity to discuss dietary considerations for patients with FCS with Wahida Karmally, DrPH, RD, CDE, CLS, FNLA, director of nutrition, Irving Institute for Clinical and Translational Research, Columbia University, New York, NY.
Patients with FCS need to severely limit their fat intake. How many grams of fat are permissible daily?
When triglycerides are severely elevated (>1000 mg/dL), it suggests impaired or absent LPL activity. In such cases, a very low-fat diet (<10% of energy obtained from fat) decreases the production of chylomicrons and very low-density lipoprotein. For a 2000-calorie diet, no more than 20 g of fat should be consumed daily.
What would a menu with that level of fat intake look like?
The patient’s menu would favor complex carbohydrates, rather than simple and refined carbohydrate products, which are often heavy in fat and sugar, including fructose.
What about healthy fats—monounsaturated and polyunsaturated fats, including essential fatty acids?
Patients should continue to include essential fatty acids in their diets, striving to obtain 11g of omega-6 daily and between 1.1 and 1.6 g of alpha-linolenic acid daily. In addition, medium-chain triglycerides (MCTs) should be prescribed. MCTs are absorbed directly into the portal circulation and do not require bile salts for emulsification. It is crucial for patients to understand that they should not consume coconut oil as a source of MCTs. Although coconut oil contains MCTs, the majority of fatty acids in coconut oil (eg, lauric acid, palmitic acid, and myristic acid) are detrimental for this condition when consumed. Nestlé makes MCTs that are sold as a medical food through pharmacies.
Are there any targets that patients should strive to achieve with regard to their triglyceride levels? If so, how often should these targets be assessed for?
Normal levels of plasma triglycerides are less than 150mg/dL, and patients should strive to achieve as close to this level as possible. When pancreatitis is present, triglyceride levels need to be assessed every week. Otherwise, they can typically be monitored every 3 months. In most cases, the frequency of follow-up depends on the patient’s severity of disease and his or her ability to comply with a very low-fat diet.
Are any supplements recommended for patients with FCS?
As previously mentioned, MCT oil is important. Patients should start slowly, increasing consumption to attain approximately 30 g per day. Supplementation with omega-3 fatty acids is also considered.
What, if any, other lifestyle changes are recommended for patients with FCS?
In addition to adhering to a very low-fat diet, patients should watch their weight, ensuring their body mass index is in the normal range. They should also engage in regular physical activity and completely eliminate alcohol from their diet, as alcohol raises triglyceride levels.
Compliance with any strict diet is always a concern. Are there any strategies that can improve a patient’s ability to adhere to a strict low-fat diet? Any resources they can turn to?
To make an eating pattern sustainable, it should be enjoyable and easy to prepare. This requires an understanding of how to make smart selections at the supermarket, in restaurants, at social events, and on the road. Therefore, I would recommend that all patients meet with a registered dietitian to obtain a personalized eating plan that is sustainable.
Is there anything physicians should keep in mind from a nutritional standpoint when treating patients who have FCS?
It is important to avoid instructions with sound bites, such as “cut fat” or “ no carbs,” as patients find such instructions very confusing. To set patients up for success, patients must be active members in the nutrition care process. This is best achieved in collaboration with a registered dietitian. These professionals are equipped to educate the patient about his or her nutritional needs and empower him or her to “take charge” of those needs.
1. Sugandhan S, Khandpur S, Sharma VK. Familial chylomicronemia syndrome. Pediatr Dermatol
2. Rare Disease Report. Familial chylomicronemia syndrome: a genetic disorder causing build up of triglycerides and chylomicrons. http://fcs.raredr.com
. Accessed February 22, 2015.
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