Sterol Balance in Man as Plasma Cholesterol Concentrations Are Altered by Exchanges of Dietary Fats*

Abstract

Although the hypocholesteremic effect of unsaturated dietary fats has been repeatedly demonstrated, the mechanism underlying this effect is by no means clear. Four possibilities exist: 1) decreased cholesterol synthesis, 2) increased excretion of cholesterol or its metabolites, or both, 3) shift of plasma cholesterol to some other tissue(s), or 4) some combination of these factors.In a previous study of a single patient in this hospital (2) significantly increased excretion of neutral but not acidic fecal sterols was demonstrated when unsaturated fat replaced saturated fat in the diet. The present study extends that single experience to five studies in four other patients and utilizes a different and more generally useful methodology.An adequate evaluation of steroid 1 excretion depends first on devising a satisfactory procedure for quantitative isolation of fecal neutral steroids and simultaneously of other metabolic end products, notably the fecal bile acids; and second, on measuring accurately these excretion products by means that take into account the numerous chemical forms of these excretion products, some of which are still not identified.

Which are the greatest recent discoveries and the greatest future challenges in nutrition?

“…Why do saturated and trans-unsaturated fatty acids raise and cis-unsaturated fatty acids lower LDL cholesterol? Many mechanisms have been proposed, but none entirely satisfactory (Spritz et al, 1965;Spritz and Mishkel, 1969;Beynen and Katan, 1985;Fox et al, 1987;Lin et al, 2005).…”

The response of lipoproteins to dietary fat and cholesterol in lean and obese persons

“…In spite of 40 years of research, the mechanisms that mediate the effects of fatty acid saturation on lipoprotein levels have not been clarified [36][37][38], and that makes it difficult to speculate why obese subjects would be less responsive to dietary fat quality than lean subjects. In contrast, the pathway from dietary cholesterol to plasma LDL is clear [39]: dietary cholesterol adds to the cholesterol that goes from the gut to the liver where it suppresses expression of the LDL receptor in hepatocytes.…”

Oxidative Stability of Grape Seed Oils Under Different Roasting Conditions

“…다른 식물성 유지와 마찬가지로 포 도씨유도 불포화지방산의 함량이 매우 높으며, 포도씨유의 주요 불포화지방산은 linoleic acid(70～75%)로 알려져 있다 (5,6). 체내에서 불포화지방산은 prostaglandin 등의 생리활 성 물질로 전환되는 성분으로 혈장 very low-density lipoprotein과 low-density cholesterol의 농도를 저하시켜 동 맥경화나 당뇨와 같은 질병의 발생을 낮춰주는 효과가 보고 되었다 (7,8). 높은 함량의 불포화지방산으로 인하여 포도씨 유는 쉽게 산패될 것으로 생각되어지나 토코페롤 및 카테킨 류의 항산화 성분에 의하여 산패가 억제된다고 알려져 있다 (9,10 …”