Nutrition Noteworthy

The intranasal application of zinc is a new option available for the treatment of the common cold. At a glance the current research is conflicting regarding the effect of intranasal zinc on the common cold. However, with more careful review it is apparent that the available research supports the observation that intranasal zinc, in the correct dose/formulation, significantly reduces the duration of naturally occurring common colds. But, the potential risk of anosmia (loss of smell) is also well established. This paper focuses on the research that has evaluated the effect of intranasal zinc on the common cold.

Due to the rapid growth of the organic food industry and the increasing popularity of organic fruits and vegetables, the health benefits and risks of organic produce are issues of significant importance. This review will compare organic and conventional produce in terms of nutritional value, pesticide contamination, and microbiological safety. The current literature shows that organic produce tends to contain higher levels of vitamin C and lower levels of nitrates, though more well controlled studies are necessary in order to reach any definitive conclusions. It has been definitively shown that organic produce contains fewer and lower levels of pesticides than conventional produce, though the long-term health consequences of ingestion of pesticides, and the clinical relevance of fewer and lower levels of pesticides in organic food, has yet to be determined. Organic farming methods can potentially lead to microbiological contamination, but the literature has shown that organic produce does not carry any higher risk of significant microbiological contamination than conventional produce. These findings in the current literature seem to suggest that organic produce can potentially be more beneficial, but certainly not more harmful, than conventional produce for the health of the consumer.

With heart disease being the leading cause of death in the US and an important cause of mortality worldwide, there has been increasing interest in dietary supplements that may provide adjunctive therapy to standard medications. Fiber products, traditionally used for alleviating gastrointestinal states such as constipation, have also been investigated for their potential beneficial cardiovascular effects. Psyllium is a soluble dietary fiber derived from the plant Genus Plantago. The FDA has recently approved the use of daily intake of 3g to 12g of psyllium seed husks to reduce the risk of heart disease, when taken as part of a low fat, low cholesterol diet. This paper reviews recent clinical studies investigating the effects of psyllium on cardiovascular risk factors, focusing specifically on total and LDL cholesterol. The majority of studies show that psyllium modestly lowers total and LDL cholesterol levels in mild to moderate hypercholesterolemic people. The effects of psyllium depend on a wide range of variables including dosage and baseline lipid levels. The mechanism for cholesterol reduction likely involves increasing bile acid excretion and synthesis, and by affecting the levels of hepatic enzymes involved in lipid metabolism. Further studies will need to be conducted to identify the efficacy of psyllium use as adjunctive therapy with standard medications such as statins, its effects on normocholesterolemic people, and its long term safety profile.

The pathogenesis of obesity is multi-factorial; both genetics and the environment influence the many variables that regulate body weight, metabolism, and eating behavior. The loss of control of eating behavior associated with obesity is analogous to the compulsive drug taking behavior observed in drug-addicted individuals. The American Society of Addiction Medicine first proposed the hypothesis of a food addiction over 10 years ago. Evidence from clinical observations and experimental research, in particular neuroimaging studies, provides substantial support for the relationship between binge-eating obesity, addiction, and the DA reward system.

There is a significant amount of epidemiological and clinical data suggesting a connection between the intake of omega-3 fatty acids and improved mental health. Both large scale studies have found decreased prevalence of mood disorders in nations with higher levels of fish consumption, and clinical data is accumulating that administration of omega-3 fatty acids may be beneficial in treating mood disorders. With further research, these agents may prove to be valuable therapeutics in the treatment and prevention of depression, bipolar disease, and other disorders of mood.

Given the contribution of nutrition to overall health and the limited time of outpatient visits, medical students and physicians need specific questions and assessment tools that quickly and reliably identify if further dietary assessment is warranted. This article reviews the state of the literature regarding tools for rapid identification of poor versus healthy diet in general medical patients. The literature includes expert guidance on screening for poor diet in primary care, and a number of assessment instruments exist that may be useful in the clinical setting, for which limited reliability and validity analysis has been performed. Some groups are also actively working to create brief, valid instruments, and these are available to physicians. However, additional research guiding physicians on how to perform efficient and effective nutritional screening is greatly needed.

The use of creatine supplementation continues to be a hotly debated and relevant topic for health care professionals, amid its widespread use among young people and the mass of research with inconclusive or questionable outcomes. While the argument that creatine is an effective anaerobic ergogenic aid has a wealth of evidence, the case for the safety of its long term use does not. This fact is worrisome given the cavalier manner in which many use the supplement, as considerations of genetic predispositions to kidney disease, underlying occult or known disease states, or even metabolically competing medications are often excluded from the decision of whether, how much and for how long to use the creatine supplement. While evidence to date does not suggest a widespread pattern of severe side effects from its use, the research is silent regarding risks in the context of disease, such as impaired glomerular filtration. In an era where the burden of proof lies with the health care professional, who operates under the principle of evidence based medicine, physicians should work to communicate this lack of clarity, to urge caution and to demand more comprehensive research.

Bulimia nervosa serves as a disease model for a variety of physiological problems associated with improper nutritional intake. Although there is extensive research on women who are actively bulimic, very little has been done to follow-up on women who have overcome bulimia. Amennorhea, anemia, constipation, severe dehydration, arrhythmias, osteoporosis, and diabetes can all be health risks due to impaired nutrition while a patient is bulimic. Fortunately, some of the health problems caused by impaired nutrition in women with bulimia nervosa do not persist after recovery. Once a woman is no longer regularly bingeing and purging, problems such as amenorrhea, anemia, severe dehydration, and acute heart dysrhythmias are no longer big concerns. However, because of their impaired nutrition, past bulimics may remain at increased risk for osteoporosis, reproductive problems, diabetes, and cholesterol elevation. Even after the ritual of bingeing and compensation has been overcome, it is important for health care providers to monitor the long-standing effects of a past history of bulimia in their patients. Longitudinal studies in this recovered population are lacking, and really should be conducted to truly assess what health risks these women have because of their improper nutrition in the past.

“Yo-yo” dieting, or weight cycling, is defined as weight loss followed by subsequent regain of the lost weight. It is a phenomenon most often seen in overweight or obese individuals, but those who do not need to lose weight, such as athletes, actors, and models, also practice it. This review critically examines the recent literature on weight cycling with respect to metabolic changes, cardiovascular health, chronic disease, mortality, osteoporosis, and immunocompetence. No consistent positive association was found between weight cycling and metabolic changes, cardiovascular health, chronic disease, and mortality. Studies show possible harmful effects for large weight regains and some cardiovascular risk factors and type 2 diabetes in overweight/obese individuals. Harmful metabolic changes may also occur in young, normal weight women who do not need to lose weight, but this finding needs to be repeated. Preliminary studies also show possible bone density loss in weight cyclers as well as decreased immune function.

Many protein and amino acid supplements are touted as being able to maximize the gains achieved from resistance exercise by preventing muscle protein catabolism and stimulating anabolism. If effective, such supplements would be useful not only for athletes and for those trying to increase their fat free mass, but also for patients recovering from injuries or burns and for the prevention of aging-associated muscle loss. It has been shown that intravenous infusion or oral administration of complete mixtures of amino acids has a positive effect on muscle protein synthesis and net muscle anabolism following exercise. Since nonessential amino acids are synthesized by the body in response to resistance exercise, administration of essential amino acids only following exercise has the same positive anabolic effect on muscle as complete amino acid supplementation. Furthermore, oral administration of whole proteins following training has a similar anabolic effect, as whole proteins such as whey and casein are also effective sources of essential amino acids. In addition to mixed amino acid and whole protein supplements, a number of single amino acids are marketed as having anti-catabolic and/or anabolic effects on muscle protein, including glutamine, asparagine, ornithine, and beta-hydroxy-beta-methylbutyrate (HMB). Among these, only HMB has been shown to have positive effects on gains in muscle strength and fat free mass versus placebo in combination with a program of resistance exercise. In summary, supplementation with essential amino acids, whole proteins, and HMB in conjunction with resistance training can maximize the gains of exercise alone.

Iron deficiency is the most common nutritional disorder in the world. It is estimated that as many as 4-5 billion people, 66-80% of the world’s population, may be iron deficient. These staggering numbers correlate with significantly poorer performance on psychomotor and mental development scales and behavioral ratings in infants, lower scores on cognitive function tests in preschool children, lower scores in cognitive function tests and educational achievement tests in school-age children, and poor pregnancy outcome. However, 90 percent, of the iron deficiency is found in developing nations. It is very important to implement a form of intervention that is both effective and economically sound. Iron fortification programs have been implemented worldwide. For Southeast Asia, NaFeEDTA-Fortified fish sauce is the key. Recent studies clearly show that fish sauce fortified with NaFeEDTA is efficacious in improving iron status and reducing the prevalence of IDA in anemic Vietnamese women. These results add to growing body of evidence that food fortification with iron compounds having high bioavailability is a useful approach to combat iron deficiency and IDA. The purpose of this review article is to explore the epidemiology of IDA and evaluate the utility, cost and benefit of the fortification of fish sauce with NaFeEDTA.