Diet research needs

Finally, it is clear that much more research needs to be performed to connect the disciplines of colloid science and nutrition, especially in the application areas of functional foods and delivery systems. The combination of information from both in vitro and in vivo studies is evidently required in order to be able to understand properly the complex physicochemical processes that can occur during the digestion of food colloids. Our ultimate objective must be to make use of this knowledge to produce effective strategies for the formulation of a healthier diet with optimized bioavailability of the most desirable ingredients. 

Reeves (1997) has discussed the current recommendations of the American Institute of Nutrition (AIN) for assembling rat diets. Issues discussed include the use of sugar versus starch as the source of carbohydrate, methionine versus cystine as the source of cysteine, and the best oil for providing the essential fatty acids. In embarking on any study, the researcher needs to reevaluate the role of each of the recommended nutrients to make sure that their quantities suit the purposes of the planned experiment. For example, although the AIN recommends using casein as the source of protein, researchers interested in the interactions of calcium and phosphate need to take into accoimt the fact that casein contains significant amounts of phosphate. 

Research Needs. Over the years L-ascorbic acid has been shown to be an essential nutrient for many insects including species of Lepidoptera, Orthoptera, Coleoptera, and Diptera. Others such as cockroaches, houseflies, and mealworms are reared on simple diets without added ascorbic acid. Perhaps those insects require very low levels of vitamin C in their diets. A sensitive analytical method is needed to measure levels of L-ascorbic acid and dehydroascorbic acid in insect tissue and food. Such a method, which is likely to be developed using HPLC with electrochemical detection, could be used to monitor vitamin C levels in feed ingredients as well as in tissues during an insect s life cycle. This information is needed to determine whether ascorbic acid is used to... 

Additional research needs to be carried out on mineral retention when pectin is present in the diet. Iron showed both decreased absorption and no significant differences from the control. In general the longer studies showed less differences in iron retention from control levels than did the load dose or very short studies. Other minerals studied did not significantly change when pectin was present in the studies reported. 

Sappington KG (2002) Development of aquatic life criteria for selenium a regulatory perspective on critical issues and research needs. Aquat Toxicol 57 101-113 Schubert A, Holden JM, Wolf WR (1987) Selenitrm content of a core group of foods based on a critical evaluation of published analytical data. J Am Diet Assoc 87 285-299 Shanker AK (2006) Countering UV-B stress in plants does selenium have a role Plant Soil 282 21-26... 

Phytochemicals have been the subject of many studies evaluating their effects in relation to common chronic human illnesses such as cancer and cardiovascular diseases. These studies encounter difficulties in using this information to influence the dietary patterns of consumers because in the past they have used models or experiments with animals. However, in the last decade, researchers have moved away from animal studies in favour of human cell models or human intervention studies. Scientists still need to determine the likely incidence of illness from exposure to known amounts of a given natural compound in the diet and specifically in relation to the complex matrices of whole foods. Therefore, it is inevitable that some animal studies have to be continued for toxicological studies. 

Hazard evaluation posed by organotin compounds to natural resources is predicated partly on their chemical composition, partly on their concentration and persistence in abiotic materials and diet items, and partly on their availability to organisms. In each of these areas, key data are missing for promulgation of effective regulations. It seems that additional research is needed in eight areas to acquire these data ... 

Concern for the continued widespread use of chlordane centers on its ability to cause liver cancer in domestic mice. Other adverse effects in mammals, such as elevated tissue residues and growth inhibition, were frequently associated with diets containing between 0.76 and 5.0 mg chlordane/kg feed. Metabolism of technical chlordane by mammals results primarily in oxychlordane, a metabolite that is about 20 times more toxic than the parent compound and the most persistent metabolite stored in adipose tissues. Chlordane interactions with other agricultural chemicals produced significant biological effects in warm-blooded organisms, indicating a need for additional research on this subject. 

Proposed free cyanide criteria suggest that sensitive species of aquatic organisms are protected at <3 pg/L birds and livestock at <100 mg/kg diet and human health at concentrations of <10 pg/L drinking water, <50 mg/kg diet, and <5 mg/m3 air (Eisler 1991) (Table 15.6). In aquatic systems, research is needed in several areas ... 

For protection of domestic cattle, feeds should contain <0.05 mg diflubenzuron/kg FW. Cottonseed may be added to cattle diets provided that diflubenzuron concentrations in the seed do not exceed 0.2 mg/kg FW and that cottonseed composes <17% of the total diet bulk (Gartrell 1981). Diflubenzuron causes biochemical upset, as judged by lowered testosterone levels in chickens and rats (USEPA 1979), altered glutathione 5-transferase activity in mouse liver (which adversely affects the ability to detoxify foreign substances by way of conjugation Young et al. 1986), and disrupted hydroxylamine activity in human infants (USEPA 1979). Additional research seems needed on biochemical alterations induced by diflubenzuron. No diflubenzuron criteria are currently recommended for protection of avian and mammalian wildlife. All data available suggest that wildlife species are about as tolerant to diflubenzuron as are domestic poultry and livestock however, the wildlife database seems inadequate for practicable criteria formulation. 

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