Sphingolipids are each comprised of a sphingoid base backbone, amide-linked fatty acids (normal and 2hydroxy fatty acids) and a polar headgroup, such as phosphocholine or hexose. Sphingolipids are frequently to be found in eukaryotic organisms, with mammalian sphingolipid trans-4-sphingenine (sphingosine) being most prevalent. Others such as sphinganine (dihydrosphingosine) and 4-hydroxysphinganine (phytosphingosine) frequently occur in small amounts. Plant and fungus sphingolipids display a diversity of sphingoid base structures, such as those of trans-8-sphingenine, cis-8-sphingenine, trans-4, trans-8-sphingadienine, trans-4, cis-8-sphingadienine, 4-hydroxy-trans-8-sphingenine, 4-hydroxy-cis-8-sphingenine and 9-methyl-45

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Sphingolipids have attracted attention as physiologically functional lipids. We determined their class and content in Japanese meals that had been prepared by a nutritionist, mainly by using HPLC-ELSD. In all 12 meals tested, cerebroside and/or sphingomyelin were generally detected as the major sphingolipids. The total amounts of sphingolipids in typical high-and lowcalorie meal samples over 2 days were 292 and 128 mg/ day, and 81 and 45 mg/day, respectively. Key words: sphingolipid; cerebroside; sphingomyelin; ceramide; daily intake Sphingolipids are known to exist in eukaryotes as components of the biological membrane and are involved in cellular membrane traffic and signal transduction. 1,2) Moreover, sphingomyelin, glucosylceramide (cerebroside) and ceramide are abundantly present in an animal epidermis in spite of differences due to species. [3][4][5] Of these, free ceramide included in the human stratum corneum has the function of epidermal moisture retention or as a protection system against external irritation. 6,7) Various physiological functions of dietary sphingolipids, such as preventing early-stage colon cancer [8][9][10] and improving the skin barrier function, 11,12) have been demonstrated. The most common sphingolipid currently used as a foodstuff is cerebroside extracted from plants, which is mainly composed of sphingoid bases distinctive from those of mammals, the plant type being sphingadienine and phytosphingosine and the mammal type being 4-trans sphingenine (d18:1 4t ) as major sphingoid bases. However, apart from d18:1 4t , the sphingoid bases are hardly absorbed in the intestinal tract. 13,14) It is considered that the routinely ingested sphingolipids are mainly sphingomyelin from animal foodstuffs and mainly cerebroside from plant foodstuffs. 15,16) In reports concerning the intake of sphingolipids, Vesper et al. have summarized the amounts of sphingolipids in foods from estimated data in the available literature; 15) however, their class and how much sphingolipid is ingested daily have not been clarified. In addition, Sugawara and Miyazawa have reported the daily intake estimated from the contents of cerebroside in various plant foodstuffs. 16) The classes and contents of sphingolipids in certain meals for healthy energetic people cooked by a nutritionist were analyzed in the present study. Typical meals for older people, which are generally low-calorie, were also comparatively investigated.Six meal samples (breakfast, lunch and dinner) in 2 d for healthy energetic people were kindly donated by the Kushiro station of the Ground Self-Defense Force (Hokkaido, Japan). Six meal samples for 2 d prepared in a home for senior citizens in Nakasatsunai-mura (Kasaigun, Hokkaido, Japan) were used as low-calorie meals. The composition of food groups and calories in each meal are shown in Table 1. The energy content of the high-calorie (HC) meals from the Self Defense Force was approximately 3,000 kcal per day, exceeding the recommendations for regular Japanese men of 1,800 to 2,000 kcal; however, t...

The effects of dietary plant and yeast cerebroside (glucosylceramide), a major sphingolipid in plants and yeast, on atopic dermatitis (AD) like symptoms were investigated in a mouse model. After 7 wk of feeding with a diet containing maize glucosylceramide, plasma IgE levels became significantly lower and in contrast, the levels of interleukin (IL)-12, which induces cellular immunity, became significantly higher in the AD mice than in the controls. However, the sphingolipid constituents of the skin fraction in the maize glucosylceramide fed group did not contain sphingoid bases of plant origin, such as 8-unsaturated sphingoid bases. The results of the present study indicated that dietary plant glucosylceramide prevented AD-like symptoms in AD model mice via regulation of Th1/Th2 balance.Practical applications: Dietary plant and yeast glucosylceramides have been shown to suppress AD-like symptoms in AD model mice via regulation of helper T-cell Th1/Th2 balance. Glucosylceramides are capable of preventing AD and may be useful in skincare products.