Nutrition, diet and immunosenescence

Ageing is characterized by immunosenescence and the progressive decline in immunity in association with an increased frequency of infections and chronic disease. This complex process affects both the innate and adaptive immune systems with a progressive decline in most immune cell populations and defects in activation resulting in loss of function. Although host genetics and environmental factors, such as stress, exercise and diet can impact on the onset or course of immunosenescence, the mechanisms involved are largely unknown. This review focusses on identifying the most significant aspects of immunosenescence and on the evidence that nutritional intervention might delay this process, and consequently improve the quality of life of the elderly

The immune system and the impact of zinc during aging

The trace element zinc is essential for the immune system, and zinc deficiency affects multiple aspects of innate and adaptive immunity. There are remarkable parallels in the immunological changes during aging and zinc deficiency, including a reduction in the activity of the thymus and thymic hormones, a shift of the T helper cell balance toward T helper type 2 cells, decreased response to vaccination, and impaired functions of innate immune cells. Many studies confirm a decline of zinc levels with age. Most of these studies do not classify the majority of elderly as zinc deficient, but even marginal zinc deprivation can affect immune function. Consequently, oral zinc supplementation demonstrates the potential to improve immunity and efficiently downregulates chronic inflammatory responses in the elderly. These data indicate that a wide prevalence of marginal zinc deficiency in elderly people may contribute to immunosenescence

EVALUATION OF PROTEIN QUALITY USING MICE VS. RATS

Experiments were designed to investigate the possibility of using mice as model animals for the evaluation of protein quality, and to compare it with rats under the same conditions. Parameters measured were protein efficiency ratio, net protein ratio, protein digestion and relative protein value. Six sources of protein were tested at three dietary levels for each. Measurements were taken at four different periods of feeding, thus, the effects of dietary level of protein and the length of the feeding period were studied. Results on mouse experiment indicated that the highest PER values were obtained at 6 and 8% levels of dietary protein with significantly lower values when 11% levels were fed. The highest NPR values were obtained at 6% level of dietary protein then declined when 8 or 11% levels were fed. The highest efficiency regarding PER and NPR were obtained when mice were fed for 10 days than when they were fed for 14, 21, or 28 days of experiment. High quality protein sources were needed at lower levels in the diet for shorter periods of time to obtain the maximum efficiency when compared to poor quality sources of protein. Results for protein digestion did not correlate with those of PER, NPR or RPV indicating that protein digestion is a poor measurement. However, PER, NPR, and RPV were highly correlated. Results of rat experiment were in agreement with what was reported in the numerous works for rat bioassay in the literature review. Rate of body weight gain increased with increasing levels of dietary protein and the PER reached a maximum value, then decreased. Values of NPR tended to fall with increasing levels of dietary protein. PER values tended to increase gradually with prolonged period of feeding, then decline. The maximum PER values were obtained when 10% level of dietary protein was fed for a period of 15 days. Likewise mice experiment, PER, NPR, and RPV correlated highly while protein digestion correlated poorly with the other methods used. In general mice appeared to be influenced by the same factors as rats when used for the evaluation of protein quality. Mouse could be used as a model animal for protein quality evaluation with the advantages of small animal size, lower feed intake, shorter period of feeding, plus is highly desirable for experiments involving the use of isotopes or whole carcass analysis. A dietary protein level of 8% for a feeding period of 10 days would be suitable for use with mice instead of a 10% dietary level for a 28 day feeding experiment in rats. Whole eggs could be used as a suitable reference standard protein for mouse bioassay

What You See Is Not Always What You Get: Thoughts on the O.J. Trial and the Camera, 14 J. Marshall J. Computer & Info. L. 555 (1996)

This commentary is from the unique perspective of Roger Cossack, host of CNN’s “Burden of Proof.” In it, he reflects on the O.J. Simpson trial and the effect televising it had. He concludes that televising the trial revealed the depth of racial conflict that divides our country. This was shown by issues involving pre-trial publicity, control of the courtroom, racism in reporting, the failure of DNA evidence and prior spousal abuse to convince the jury, and the effectiveness of counsel