Nutrition Bytes

Iron deficiency has important clinical significance in the American population. Many women are at risk for iron deficiency anemia and those who are blood donors are more susceptible for iron deficiency anemia due to the increased blood loss. The traditional measure of hemoglobin fails to detect the first two stages of iron deficiency. Because female blood donors are at higher risk for iron deficiency it is necessary to improve detection of the earlier stages of iron deficiency before anemia and other clinical symptoms are manifested. Female blood donors exhibit a protective mechanism and have been found to increase rates of iron absorption due to a hypothesized increase in their setpoint for iron storage. The increased demand for iron as a result of blood donation is due to increased activity of erythropoiesis. Iron supplementation may be an important factor in preventing iron deficiency anemia in repeat female blood donors.

There are many preventable and reversible risk factors associated with cardiovascular disease. Recently, there have been several reports associating the elevated levels of homocysteine, an intermediate that is involved in the interconversion of methionine and cysteine, with arteriosclerotic cardiovascular disease. There appears to be consistent evidence that these homocysteine levels can be significantly reduced by dietary and supplemental intake of folic acid, vitamin B12, and vitamin B6. Elevated levels of homocysteine have become as important as high cholesterol levels and information on prevention has become equally important. Supplements of B vitamin are being strongly encouraged because they are not harmful and inexpensive. Changes in levels of these vitamins can lower homocysteine levels and ultimately reduce an individual risk for cardiovascular disease.

Panax ginseng is used in traditional Chinese medicine as a prophylactic, a stimulant, and a treatment for various diseases. In addition, ginseng has been found to enhance the immune system and possess an anti-tumor effect. Ginseng appears to stimulate humoral and cell-mediated immune responses and the subsequent increase in titers of lymphocytes and circulating antibodies. Furthermore, ginseng's cancer-prevention properties seem to be mediated through the increased production of interferons and cytokines, which activate natural killer and cytotoxic T-cells that can served to lyse or inhibit growing tumors. Both clinical and epidemiological studies indicated that Panax ginseng can reduce the incidence of cancer in vivo. These results suggest that ginseng shows antitumor effects as an immunomodulator.

In Germany extracts of Hypericum perforatum, commonly called St. John's wort, are among the most widely prescribed antidepressants, accounting for over 25% of antidepressant prescriptions. Such use exemplifies the increasing interest surrounding herbal medicines throughout the United States and Europe and an increasing need for research on unregulated alternative therapeutics. This paper reviews recent investigations of receptor binding affinity of extracts of H. perforatum as well as clinical trials and meta-analyses of its efficacy as a herbal antidepressant. Significant receptor affinity has been demonstrated for GABA, benzodiazepine, adenosine, NMDA, serotonin (5HT1) and monoamine oxidase with the latter two most likely implicated in its therapeutic action. Meta-analyses have consistently demonstrated significant therapeutic benefit from H. perforatum extract over placebo in mild, moderate and severe depression. This benefit is not significantly different from benefits derived from tricyclic antidepressants except after 6 weeks when H. perforatum benefits are moderately less. However, reduced side-effects may make H. perforatum extract a preferred treatment over many current antidepressant medications.

With the great interest in exercising, competing, and winning in today's world, it is an interesting question to ask if caffeine, the most popular stimulant in the world, can help to improve performance in endurance exercise activities. This study looks to see if caffeine is an ergogenic aid in exercise activities requiring greater than 20 minutes to complete. We find that caffeine has, in fact, been shown, during this decade, to increase exercise performance in events that take greater than 20 minutes to complete. However, compounds consumed with caffeine can negate its ergogenic effect. We also see that, contrary to popular belief, caffeine does not significantly increase dehydration in exercising athletes, as it does in resting individuals. This is a significant result for athletes, such as marathoners and triatheletes, who consume caffeine during a long race. The mechanism by which caffeine acts as an ergogenic aid in endurance exercise is unknown, but has been proposed to be related to the reduction of the concentration of plasma K observed in athletes after consuming caffeine vs. placebo. Additionally, a psychological effect caused by caffeine is hypothesized to decrease one's perception of exertion.

Atherosclerosis leads as a cause of death and disability in Europe, North America and Japani. It has been previously determined that high LDL:HDL ratios, family history, smoking, gender, chronic hypertension and age are all risk factors for developing atherosclerotic plaques and subsequent cardiovascular disease (CVD). Recently, evidence is emerging that high levels of stored iron might constitute yet another risk factor for atherosclerosisii,iii,iv. This is consistent with the proposed mechanism of atherogenesis, whereby macrophages take up an oxidized version of LDL to become foam cells (which compose the gruel of the plaque)v. Body stores of iron would act as pro-oxidants to catalyze the formation of oxidized LDL from normal serum LDL. Thus, high levels of iron would promote increased foam cell development and plaque enlargement. Although some studies have shown a lack of association between body iron stores and atherogenesis vi,vii,viii, it is feasible that repeated phlebotomy (which would decrease iron s tores) might prove to lower one's risk of developing atherosclerosis and CVD.

Panax ginseng is used in traditional Chinese medicine as a prophylactic, a stimulant, and a treatment for various diseases. In addition, ginseng has been found to enhance the immune system and possess an anti-tumor effect. Ginseng appears to stimulate humoral and cell-mediated immune responses and the subsequent increase in titers of lymphocytes and circulating antibodies. Furthermore, ginseng's cancer-prevention properties seem to be mediated through the increased production of interferons and cytokines, which activate natural killer and cytotoxic T-cells that can served to lyse or inhibit growing tumors. Both clinical and epidemiological studies indicated that Panax ginseng can reduce the incidence of cancer in vivo. These results suggest that ginseng shows antitumor effects as an immunomodulator.