Role in human diet

The main sources of plant lipids of significance in diets are the leaves, which primarily provide a source of fatty acids for grazing animals and seed oils, which play a large role in human diets and an increasing one in farm animal diets. These are representative of the structural and storage lipids respectively and differ widely in fat composition (Sections 3.3 and 3.10). 

Carotenoids play a key role in human diet by virtue of their metabolism to vitamin A (retinol, 61). As the prosthetic group associated with the light-harvesting pigment rhodopsin, retinol is critically involved in visual processes. It is also a participant in growth and development processes, so vitamin A deficiency, which is estimated to inflict 124 million children worldwide, can have serious consequences for long-term health (Beyer et al. 2002). The antioxidant properties of carotenoids have also been implicated in the protection against heart disease and cancer (Fraser and Bramley 2004). 

KUHNAU j (1976) The flavonoids. A class of semi-essential food components their role in human nutrition , World Rev Nutr Diet, 24, 117-91. 

Diet plays an important role in most of the chronic diseases that are the largest causes of morbidity and mortality in the developed world. In a reductionist approach, scientists have often made the role of individual nutrients in the maintenance of health the focus of their research. This approach, and in particular the discovery of essential nutrients and their roles in disease prevention, has been instrumental in the elimination of deficiency diseases in large parts of the world. However, nutrients are not consumed in isolation, but as components of whole foods and in an infinite number of combinations. In addition, foods contain a myriad of chemicals (or non-nutrients) which either serve no role in human metabolism or for which the role has not yet been elucidated. This introduces a significant level of complexity, which may be difficult to unravel. 

Stavric B. 1994. Role of chemopreventers in human diet. Clin Biochem 27(5) 319—332. 

The use of animal fats by humans may well predate civilization. As the depot fats of animals are readily noticed during the butchering of a slaughtered animal, are easily harvested, and are available in the absence of plant domestication and the adoption of established agriculture, it is probable that animal fats were the hrst lipids employed as industrial and as distinct edible lipids by humans. This is evidenced by the fact that the paints used in prehistoric cave paintings were animal fat-based, as were the fuels in the lamps that illuminated the cave artists at their work. Despite a tremendous diversihcation to include other lipid types over the intervening centuries, animal fats still play a prominent role in our diets, industry, and commerce. 

This chapter deals with two important and related topics in archaeological investigations die environment in which people lived, and the foods that they ate. The environment plays a major role in die diet that is available to hnman groups. This relationship is seen both in terms of the specific kinds of plants and animals that are available and in terms of changes in climate and resources over time that impact the human population. 

The recent cloning and characterization of these desaturases is of great interest to the scientific conununity because the products of the membrane-bound systems include A -18 2 and A -18 3, both of which are essential to the human diet, and are thought to play a major role in human health and disease. 

In summary, oxysterols are known to exist in atherosclerotic lesions and have been demonstrated in cell-culture experiments to have profound cellular effects that could influence the development, progression, and reversal of atherosclerosis. The key question in this field of research, however, is whether the concentrations of oxysterols in vivo are high enough to influence atherogenesis. Thus far, only the oxysterol-activated nuclear transcription pathway has been directly supported by in vivo data, and even in this case the precise roles and identification of the activating oxysterols in vivo have not yet been elucidated. Moreover, to the extent that oxysterols are generated in vivo and not just obtained from the diet, their role in human atherosclerosis has been questioned by clinical trials showing little or no protective effect of antioxidants on atherosclerotic coronary artery disease (K.J. Williams and E.A. Fisher, 2005). 

The overall objective of this chapter is to review the past, present, and future role of the sweet potato (Ipomoea batatas [L.] Lam) in human nutrition. Specifically, the chapter describes the role of the sweet potato in human diets outlines the biochemical and nutritional composition of the sweet potato with emphasis on its (3-carotene and anthocyanin contents highlights sweet potato utilization, and its potential as value-added products in human food systems and demonstrates the potential of the sweet potato in the African context. Early records have indicated that the sweet potato is a staple food source for many indigenous populations in Central and South Americas, Ryukyu Island, Africa, the Caribbean, the Maori people, Hawaiians, and Papua New Guineans. Protein contents of sweet potato leaves and roots range from 4.0% to 27.0% and 1.0% to 9.0%, respectively. The sweet potato could be considered as an excellent novel source of natural health-promoting compounds, such as p-carotene and anthocyanins, for the functional food market. 

Describe the role of the sweet potato in human diets... 

The data presented in this chapter show that the pecan can play a significant role in human nutrition and health on account of its high and special nutritional components. Hence, these nutritional attributes indicate that the pecan can serve as an important healthy food in the human diet. With respect to functional lipid characteristics of the pecan, the nuts are good sources of natural antioxidants... 

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