Human health reproductive problems

Zinc is also an essential food element in the human diet. Too Httle zinc in the diet can lead to poor health, reproductive problems and a lowered abHity to resist disease. Taking too much zinc into the body through food, water or dietary supplements can also affect health. The levels of zinc that produce adverse effects are higher than the Recommended DaHy AHowances, which are 15 mg/day for men, 12 mg/day for women, 10 mg/day for children and 5 mg/day for infants. 

The advisability of using certain antibiotics, particularly penicillin and tetracycline, in animal feeds has been questioned because of their use in human medicine. Any use of an antibiotic that is prescribed for humans presents some risks to human health, whether the use is for humans, animals or for other purposes but. the uses also have benefits. Otherwise, they would not persist. Antibiotics are used in animal feeds to increase animal weight, increase efficiency of feed utilization, increase reproductive efficiency and decrease morbidity and mortality. These benefits to animals and animal producers are reflected in decreases in food costs to humans. There are also benefits to human health from use of antibiotics in food animals. By reducing the incidence of animal health problems, use of antibiotics in food animals reduce the transference of animal infections to humans. The contention that the effectiveness of penicillin and tetracycline for use in human medicine is rapidly diminishing as a result of the proliferation of resistant bacteria caused by subtherapeutic use of antibiotics in animal production is not supported by experimental data. Rather, the evidence suggests that a fairly stable level of resistance of the intestinal bacteria in humans has long since been established to penicillin and tetracycline as it has been in animals. 

The presence of EDCs in the body affects functions such as metabolic and reproductive processes including embryonic development, gonadal formation, sex differentiation, growth, and digestion. They are plausibly linked to diseases including prostate cancer, breast cancer, attention deficit/hyperactivity disorder (ADHD), asthma, and reproductive problems (Myers et al, 2009 Swan et al., 2000). Though not toxins in the conventional sense, EDCs lead to serious adverse health outcomes in both animals and humans. Conditions linked to exposure to EDCs, such as reproductive problems, incidence of certain cancers, asthma, obesity, diabetes, behavioral or learning disorders, and ADHD, are on the increase worldwide. Of this disease burden, 24-33% has been attributed to environmental contributions (Smith et al., 1999). 

The essentiality of manganese was established in 1931, when it was demonstrated that a deficit of it resulted in poor growth and impaired reproduction in rodents. Manganese deficiency can be a practical problem in the swine and poultry industries, and it may be a problem in some human populations. Conversely, manganese toxicity can be a significant human health concern. Here, literature related to manganese nutrition, metabolism, and metabolic function is reviewed. 

Vitamin A deficiency affects more than 100 million children around the world (Miller and others 2002) and thus remains an important public health problem in many countries. Vitamin A is essential for vision, reproduction, growth, immune function, and general health of humans (van Lieshout and others 2001). The major sources of vitamin A in the human diet are retinyl esters (preformed vitamin A) found in foods of animal origin and provitamin A carotenoids from fruits and vegetables. Unfortunately, foods containing preformed vitamin A (meat, milk, eggs, etc.) are frequently too expensive for some economically deprived developing countries, and therefore dietary carotenoids are the main source of vitamin A in these countries. 

As is the case with other organisms, the interest and focus on steroids and other endocrine-dismpting compounds in the environment have also been linked to reproductive health problems in humans, livestock, and wild animals (Colbom et al., 1993). To that effect, various researchers have reported a decrease in sperm quantity and quality in the second half of the twentieth century (Carlsen et al., 1995 Sharpe and Shakkebaek, 1993), and several reports have documented cases of reduced testis... 

As PCB production increased, more concerns were raised about the health and environmental effects of PCBs, which entered the environment through leakage, production processes, and improper disposal. The persistence and lipophilicity of PCBs resulted in its biomagnification in the environment (see DDT). Problems associated with PCB contamination in wildlife include deformities, tumors, disruption in the endocrine and reproduction systems, and death. Human exposure to PCBs occurs through environmental and occupational routes. The primary exposure... 

The tremendous achievements which have been accomplished by the judicious use of pesticides in increased world-wide food production and the control of vector-bome diseases are very evident. In addition, pesticidal materials contribute to the effective control of undesirable species of pests including insects, plants, bacteria, fungi, etc., and assist in the nutrition, growth, and reproduction of certain desirable species. However, because of widespread use in these applications, pesticides have proliferated intensely in the biosphere and thus have significantly contributed to problems of environmental pollution. For example, the effects of these chemicals on public health and the survival of species of fish and wildlife are two specific areas of critical concern. The attention which has been focused in recent years on the occiurence of residues of pesticides and their metabohtes, as well as other industrially significant chemicals in the environment, is demonstrated by the numerous reports of various official and unofficial committees of inquiry which have considered this problem and have reported the results of large numbers of assays of pesticide residues in such diverse substrates as human and animal tissues, food, plants, water, soil, and air. 

The primary problem in studying human reproduction is that many aspects of the reproductive process occur without the knowledge of either the woman or her physician. Ovulation, fertilization, and implantation all occur as concealed events. Reproductive biologists and epidemiologists, however, have recently developed new and incisive tools to associate exposures to reproductive health. While it will be years... 

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