Lipids in diet

Most accounts of the larger A,p.,.o in carnivores have attributed this effect to higher proportion of lipids in the diet of carnivores. This arises because carnivores obtain all or most of their nutrition from the flesh of other animals, a significant part of which is composed of lipid. By contrast, lipids make up a much smaller fraction of the total carbon pool in the diet of herbivores, particularly mminants which get much of their energy from digestion of cellulose. Humans who selectively use seeds and grains as food sources obtain a... 

We can now appreciate that this explanation is incorrect, because the energy food for an animal is all of its diet and not just carbohydrates and lipids. Therefore we should not expect any selective offset due to the presence of lipids in the flesh of herbivores. Indeed, in general, the average 5 Cof total consumable herbivore tissues (flesh, lipids, etc.) is very close to that of the diet, and we might not expect any difference in the isotopic composition of the collagen or carbonate of a consumer of pure Cj plants as opposed to a consumer of the flesh of Cs-eating herbivores. We must seek elsewhere for the cause of the trophic level effect on A,p.co-... 

Lipids in the diet (Figure 15-6) are mainly triacyl-glycerol and are hydrolyzed to monoacylglycerols and fatty acids in the gut, then reesterified in the intestinal... 

The major lipids in the diet are triacylglycerols and, to a lesser extent, phospholipids. These are hydrophobic molecules and must be hydrolyzed and emulsified to very small droplets (micelles) before they can be absorbed. The fat-soluble vitamins— A, D, E, and K— and a variety of other lipids (including cholesterol) are absorbed dissolved in the lipid micelles. Absorption of the fat-soluble vitamins is impaired on a very low fat diet. 

MARCKMANN p, sandstrOm b, jespersen J (1990) Effect of total fat content and fatty acid composition in diet on factor Vll coagulant activity and blood lipids, Atherosclerosis, 80, 227-33. 

Dr. Spiller is the editor of many clinical nutrition books. Among his multiauthor books are The Methylxanthine Beverages and Foods Chemistry, Consumption, and Health Effects (Alan R. Liss, 1984), The Mediterranean Diets in Health and Disease (Van Nostrand Rheinhold, 1991), CRC Handbook of Fiber in Human Nutrition 2nd Edition (CRC Press, 1993) and CRC Handbook of Lipids in Human Nutrition (CRC Press, 1996). 

In addition to more rapid absorption of lipids in animals fed casein, another mechanism that may be operative is decreased clearance of circulating lipids. Rabbits fed a casein-based semipurified diet excreted significantly less cholesterol but more bile acids in their feces than animals fed a commercial diet (18). The total sterol excretion in feces of the animals fed the casein diet was half that of the rabbits fed the stock diet. Huff and Carroll (19) found that rabbits fed soy protein had a much faster turnover rate of cholesterol and a significantly reduced rapidly exchangeable cholesterol pool compared with rabbits fed casein. Similar studies performed in our laboratory revealed that the mean transit time for cholesterol was 18.4 days in rabbits fed soy protein, 36.8 days in rabbits fed casein, 33.7 days in rabbits fed soy plus lysine, and 36.3 days in rabbits fed casein plus arginine. These data suggest that addition of lysine to soy protein... 

Not all studies of soy protein diets in humans have found significant reduction of plasma cholesterol. In addition to differences in diet formulations and soy protein preparations, one reason that has been proposed for these disparities is that there is a statistically significant negative correlation between the initial cholesterol level and the decrease of cholesterol achieved with the soy protein diet (r -0.48, p < 0.01) (23). In other words, those with normal or slightly elevated cholesterol levels would be expected to show less change in cholesterol as a result of the soy diet than individuals with markedly elevated lipids. Sirtori and associates (23) have followed a number of type II hyperlipoproteinemic patients who have been maintained on the soy... 

Perhaps the most hopeful sign of progress is the belated recognition of "paradoxical" reactions to the lipid-lowering diets that have been widely used for decades. For example, researchers at the South-Western Medical Center in Dallas repeatedly find "marked individual variations in response to the diet." In many persons these diets show little benefit, or increase LDL cholesterol, serum triglycerides, or... 

The cornerstone of treatment in primary hyperlipidemia is diet restriction and weight reduction. Limit or eliminate alcohol intake. Use drug therapy in conjunction with diet, and after maximal efforts to control serum lipids by diet alone prove unsatisfactory, when tolerance to or compliance with diet is poor or when hyperlipidemia is severe and risk of complications is high. Treat contributory diseases such as hypothyroidism or diabetes mellitus. 

Lupin seeds provide a protein- and lipid-rich diet that is almost equivalent to Soya. In order to avoid the toxic alkaloids, sweet lupin varieties have been selected by plant breeding. But in view of our results it is doubtful whether it is wise to destroy a natural resistance factor. It is thus not surprising that sweet... 

CN093 Eder, K. and M. Kirchgessner.The effect of zinc deficiency on heart and brain lipids in rats force-fed with coconut oil or fish oil diets. Z Ernah-rungswiss 1994 33(2) 136-145. 

HV154 Oda T, S. Aoe, S. Imanishi, Y. Kanazawa, H. Sanada and Y. Ayano. Effects of dietary oat, barley, and guar gums on serum and liver lipid concentrations in diet-induced hypertriglyceridemic rats. J Nutr Sci Vitaminol (Tokyo) 1994 40(2) 213-217. 

The RDAs for vitamin E are 10 mg and 8 mg a-TEday 1 for men and women, respectively. UK RNI values have not been established for vitamin E since its requirement is largely dependent on the content of polyunsaturated lipids in the diet. However, the Department of Health (1991) suggested that 4 and 3 mg a-TE day 1 are adequate for men and women, respectively. The major food sources of vitamin E are polyunsaturated vegetable oils and products derived therefrom (e.g. maragrine, salad dressings), green and leafy... 

From a dietary standpoint, the contribution of citrus lipids is insignificant and only between. 06 and. 09 percent has been found in oranges (37J. They are, however, of importance because of their effects on the development of off-flavors (12J, thus lowering the palatability of these products. The near absence of lipids in citrus makes it a desirable food for those on a limited fat diet. 

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