Sphingolipids in Food and the Emerging Importance of Sphingolipids to Nutrition

Abstract

Eukaryotic organisms as well as some prokaryotes and viruses contain sphingolipids, which are defined by a common structural feature, i.e. , a "sphingoid base" backbone such as D-erythro-1,3-dihydroxy, 2-aminooctadec-4-ene (sphingosine). The sphingolipids of mammalian tissues, lipoproteins, and milk include ceramides, sphingomyelins, cerebrosides, gangliosides and sulfatides; plants, fungi and yeast have mainly cerebrosides and phosphoinositides. The total amounts of sphingolipids in food vary considerably, from a few micromoles per kilogram (fruits) to several millimoles per kilogram in rich sources such as dairy products, eggs and soybeans. With the use of the limited data available, per capita sphingolipid consumption in the United States can be estimated to be on the order of 150-180 mmol (approximately 115-140 g) per year, or 0.3-0.4 g/d. There is no known nutritional requirement for sphingolipids; nonetheless, they are hydrolyzed throughout the gastrointestinal tract to the same categories of metabolites (ceramides and sphingoid bases) that are used by cells to regulate growth, differentiation, apoptosis and other cellular functions. Studies with experimental animals have shown that feeding sphingolipids inhibits colon carcinogenesis, reduces serum LDL cholesterol and elevates HDL, suggesting that sphingolipids represent a "functional" constituent of food. Sphingolipid metabolism can also be modified by constituents of the diet, such as cholesterol, fatty acids and mycotoxins (fumonisins), with consequences for cell regulation and disease. Additional associations among diet, sphingolipids and health are certain to emerge as more is learned about these compounds.

Activation of iNKT cells by a distinct constituent of the endogenous glucosylceramide fraction

“…It is notable that the GlcCer fraction from ruminants appears to be especially activating for iNKT cells. Ruminant milks are an abundant component of the human diet, and are rich in glycosphingolipids (34). The possibility that dietary lipids might contribute to iNKT cell activation is an exciting one.…”

Dietary Milk Sphingomyelin Reduces Systemic Inflammation in Diet-Induced Obese Mice and Inhibits LPS Activity in Macrophages

“…Dietary sphingolipids, which include sphingomyelin (SM), ceramides, and sphingosine, are mainly found in milk, eggs, and soybeans [12]. It is estimated that the average American consumes 0.3 to 0.4 grams of sphingolipids per day [12]. Sphingomyelin is considered a zoochemical, being present in animal cell membranes but absent from plants [13].…”

Steroidogenic factor-1 is a sphingolipid binding protein

“…Due to the large concentration of sphingolipids such as sphingomyelin in the plasma membrane, it was held that these molecules only served structural roles. However, over the past few decades, many studies have demonstrated that these molecules, notably ceramide and sphingosine-1-phosphate (S1P), play integral roles in mediating varied cellular processes (Hannun and Obeid, 2002;Igarashi et al, 2003;Merrill Jr. et al, 1997;Spiegel and Milstien, 2002;Spiegel and Milstien, 2003;Strasberg and Callahan, 1988;Tilly and Kolesnick, 2002;Vesper et al, 1999). Ceramide is a second messenger for events as diverse as differentiation, senescence, proliferation, cell cycle arrest, and apoptosis (Hannun, 1994;Hannun et al, 2001;Kolesnick, 2002).…”