Diatetics

A. Abstract Physical exercise is recommended widely as way to improve one’s health and reduce the risk of several diseases. However, intense physical activity has a much greater potential to worsen serum ferritin, which is not good for young fertile women. The purpose of the following research studies was to investigate the relationship between college athletes and non college athletes and their serum ferritin levels. Studies have exhibited a marked reduction in serum ferritin in college athletes in respect to non-collegiate athletes. Low ferritin levels may be due to menstrual bleeding, dietary iron intake, intensity and duration of physical activity and poor intestinal absorption. A serum ferritin concentration of < 12 ug/L is considered to be iron deficient. (1) B. Introduction There is much speculation about college athletes and non-college athletes having low serum ferritin. The reason for this suspicion is due to an increase in plasma volume which can stimulate erythopoiesis. Erythopoiesis depends on the production of erythropoietin, which is regulated by the oxygen content of the blood vessels. This volume expansion occurs in athletes at a much more rapid rate and to a greater extent than the increase in red blood cell volume. Therefore it seems to be the reason athletes experience anemic like symptoms. (2) The most conventional and easy way to improve ferritin is through a balanced diet and planned training. Let’s say you just come back from your off season and your iron and ferritin levels are good, but as soon as you start exercising heavily that volume expansion occurs and if you do not increase the iron in your diet you may get depleted iron stores. A normal ferritin level for women is 12-150 ug/mL and the primary storage form for iron is ferritin that is why ferritin gives good results for total body iron stores. The best sources are heme iron which can come from red meat and is most easily absorbed and non heme iron which can come from peas, nuts, cereals, eggs and many other things. In extreme cases such as a ferritin levels <12 ug/L (1) an oral or intramuscular supplement would help improve ferritin levels. Monitoring of these ferritin levels is conducted by measuring plasma ferritin and the degree of saturation at the end of the training period. The information researched from the following articles has been split into two categories: The first which covers college female athletes and the second covers non-collegiate female athletes. The following peer reviewed articles will be demonstrating how the effects of collegiate and non collegiate athletes can affect serum ferritin. Throughout these articles you will notice that a nutritional analysis and menstrual cycle length and intensity were mentioned and were ranked very high among factors influencing serum ferritin. C. Research Section Several studies have been conducted to test for a relationship between female college athletes versus non-collegiate athletes and their iron stores. When compiling research articles you will find many differences among different researchers and why they chose to include certain aspects; it may have been a time constraint, money, non-compliance from the subjects or not having the best equipment available. I. Collegiate Athletes A. Menstrual Cycle was not considered throughout the following One study I found on athletes and serum ferritin was done on 10 swimmers and 9 sedentary females. Serum ferritin was tested by radioimmunoassay; diet was not included in this study or menstruation making it slightly less accurate. There were no statistically significant differences among the swimmers and sedentary female’s serum ferritin levels. This study was not statistically strong enough since the loss of blood during your period can highly affect how much serum ferritin you have in your iron stores and also with the diet not included we don’t know how much animal protein these athletes actually took in. Also if their vitamin C intake is too high or too low absorption of iron can be affected or if their zinc is too high which may inhibit iron absorption. (3) B. Menstrual status is unknown and the consequences it may have on female athletes. In one study done on 40 female athletes and 40 non trained females 18-24 years of age, a self administered questionnaire was used to record food intake for 7 successive days and to learn the regularity of their menstrual cycle. To test serum ferritin they used a micro plate enzyme immunoassay test. This test was completed on both the athletes and the control group and then split into three iron deficient groups: 1). Iron depletion – serum ferritin <20 ug/l, transferrin saturation >18% and hemoglobin > 1.86 mmol/l. 2). Iron deficient erythropoiesis- SF <20 ug/l, T-sat <18 % and Hb > 1.86mmol/l. 3). Iron deficient anemia SF <12 ug/l, T-sat <16% and Hb < 1.86 mmol/l. Looking at the results in a statistical manner 6 athletes fit in category 1, 4 in category 2 and 3 in category 3. Similar results showed that in the control group 4 fit into category 1, 3 in category 2 and 3 in category 3. The results taken at baseline show a statistically significant difference in serum ferritin levels. The limitations to this study most notably had to do with the wide variation in laboratory criteria for iron deficiency and also not using more precise methods for identifying the more mild forms of iron deficiency. One other connection this study found was how well serum ferritin and dietary intake correlated. Results indicated that there was a statistically significant relationship between heme iron, animal proteins and fish when comparing the athletes to the controls. Although menstrual cycle had a high correlation with ferritin levels it is unknown in this particular study. The questionnaire only asked about regularity of menstrual cycles and to be sure no one was ammenorrheic. Therefore one possible downfall of this study is that they are unsure whether these ladies were experiencing heavy periods or even how long they lasted. The issue with the questionnaire they administered is that many ladies underestimate how much blood loss they are actually having during their periods. Over all this study found a strong correlation between athletes and low serum ferritin levels, but also finding that the control group had low ferritin stores that were shown to be significantly different. (4) Another study lasting 16 weeks measured serum ferritin through immunoassay also. This study was conducted on two female athletes and each athlete had an increase in serum ferritin throughout the study, especially subject A2. Aerobic capacity was measured by VO2 max, a 3-day food record, including one weekend was asked to be completed three separate times throughout the study. Dietary intake for subject A1 showed an increase up until week 16 when there was a large drop; A2 remained higher throughout the 16 week period. This was most likely due to A1 consuming less calories on a daily basis. Once again a major component of getting an accurate serum ferritin is the menstrual cycle which was not included. (4, 5) Several advantages and disadvantages can be found throughout all studies. When dietary iron was addressed (5) ferritin levels improved, however when dietary iron intake was not except for baseline ferritin appeared to be lower. (4) An advantage in measuring VO2 max which was not done in many studies was that it helped show the level of fitness these women were at. (5) An additional limitation noted is that these athletes participated in different sports so we do not know for sure if that had to do with the iron store depletion. (4, 5) Further testing needs to be completed on individual sports one at a time. A disadvantage with these two studies was the size of each group; one has two athletes with no comparison except each other while the other has forty female athletes and non-athletes. C. Menstrual Cycle and Diet together In another study 126 female athletes and 52 control females were brought together and asked to do a 24 hour food recall, which covered working days and weekend days, this questionnaire also contained: dietary habits, self-assessment of one’s health, menstrual cycle length, and iron containing prescriptions. A blood sample was drawn in the morning; before the sample could be taken, participants were told to stay away from iron containing preparations and also avoid heavy physical exercise. Determination of serum ferritin in this study was also completed by immunoassay but a specific type known as Boehring-Manneheim. Dietary intake was considered showing that animal, plant protein; heme, non-heme and also calcium were significantly different for athletes. The participants were interviewed about their menstrual cycle and that included length of their menstrual cycles, age at menarche and length and intensity of bleeding. The data states that menstrual bleeding was highly correlated with lower serum ferritin values in athletes versus the control group. The overall results of this study show that the control group’s serum ferritin was higher than the athletes. Also stated was the reasoning for ferritin to be higher in the control compared to the athletes and that reason being more dietary iron was taken in by the control group. (6) In one other study 100 female intercollegiate athletes involved in a variety of sports and 66 non-athletes were interviewed. Serum ferritin was also conducted using a specific type of immunoassay and that was the monoclonal antibody sandwich ELISA. Similar too many studies a questionnaire was given at baseline about menstrual cycles, including frequency, duration, and severity of periods. Dietary intake was conducted at baseline also by a 24 hour dietary recall completed by a dietitian, the computer analyzed food intake including vitamin C which may enhance iron absorption. At the end of the three month study there was not a difference in nutrient intake between the athletes and the control. This was included due to the method used to determine serum ferritin since 12 gm/dL was used as the lower limit for normal hemoglobin, while recent evidence suggests it should be 11.5 gm/dL for blacks. Secondly, the small self-administered questionnaire may not be sensitive enough to get the correct information; therefore in future research a more subjective evaluation might reveal a more significant impact of iron deficiency. Lastly, iron deficiency and athletes that do the same type of sports would give much better results, but at the same time would be found to be very difficult test. The overall results of this study varied it showed that there was no difference among athletes and the control group. (7) Although athletes and non athletes’ ferritin levels did change (6) it may have not changed in some due to poor iron intakes and their menstrual blood losses being similar. (7) In comparing these two studies the biggest differences came about at the end of each, while some(6) found the controls serum ferritin to be much lower than the endurance athletes (7) others found no significant differences among the two groups. When comparing ferritin values (6) 20 ug/L was used as the lower limit while 12 ug/L was also used as the lower limit (8) The 12 ug/L could be the reason for not having a difference among the athletes and control groups. (7) Since a much lower number can add a significant amount of people to that range. A limitation recorded in only one study was ethnicity which may have affected ferritin levels. (7) II. Non- College Athletes A. No Menstrual cycle or Dietary Analysis A study including 36 female athletes involved in a variety of sports and 36 randomly assigned non female athletes over a 6 year period were studied to check for a serum ferritin change. Serum ferritin was measured using an Abbott Ferritin Assay and the cutoff point was <12 ug/L. Limitations they noted include not taking menstrual cycle into account and not following a specific diet, it was noted that the groups consumed relatively the same calories per day. There were many positives about this study, first they did a comparison between a non-weight bearing activity and a weight bearing activity to see if the possibility of a decrease in serum ferritin was occurring from foot strike hemolysis, they took athletes from different sporting events and used anthropometric data to get them as close as possible so data would be similar. Overall there was a decrease in serum ferritin in the athletes although they noted that a much larger background questionnaire that includes, previous blood results, phase of training, and the type of sport would have been beneficial. (8) Another study conducted on white Italian women ranging in age from 18-35 was involved in recreational sports who must have been performing for 3 months at least or more than 9 hours per week. Controlled subjects were not practicing any sport activities or performing more than 3 hours a week. To get the serum ferritin the Abbott Architect Ferritin immunoassay was used, <12 ug/L, <20 ug/L and < 30 ug/L was used as the determining factor. The study found that ferritin concentrations did not differ between the control and athletes but were relatively low. A few limitations noted in the research include the study being cross-sectional when a longitudinal study could have been more beneficial in assessing temporal effects on athletes iron status, also most of the athletes were volleyball players, which is not as aerobic as some of the other sports and two other big issues not addressed was the menstrual cycle of these women and also their diet. Not knowing how intense or how long their menstrual cycles are could be the reason for the low ferritin levels and not knowing what types of dietary iron they are consuming on a daily basis also gives us in accurate data. (9) When assessing females ferritin levels dietary iron intake and menstrual cycle should always be included. The previous studies did not include either, but what they did similar was the measurement of serum ferritin by the immunoassay. Ferritin levels appear to be consistently low among athletes and non-athletes. An advantage was having a long study (8) for the fact that you could see the gradual differences over the years and seasons. B. No menstruation included but diet was included The following study was conducted on 20 aerobic dance instructors and 10 controls. The control group did not participate in regular exercise. Next, a 3 day food record was given to each participant to fill out, once returned this was analyzed by the Nutrionist III for different types of nonheme, heme and absorbable iron; which showed no differences. Ferritin was measured using an immunoraiometric assay kit, 12 ug/L was used as the cutoff. The serum ferritin values were significantly lower for the exercise group than the control group. The reason may be that the dietary analysis showed that these women consumed very little meat. There was no significant difference among calories consumed which was found to be a surprise since athletes normally consumer more, this may have been another reason for lower ferritin levels in the athletes and also that foot strike hemolysis may have contributed to lower ferritin levels. An advantage to this study was the long time period; the aerobics instructors had to have been exercising for at least 7 years, for 4 days a week for a minimum of 56 minutes. The results of this study concluded that women who perform long periods of aerobic exercise may have suboptimal serum ferritin values. (10) D. Summary and Application The studies conducted all had a similar interest and that was to see the differences in serum ferritin. Throughout the research articles there was quite a controversy over whether or not college athletes had a significantly lower serum ferritin than non collegiate athletes. Just over half of the research articles suggested that a lower ferritin level was associated with collegiate athletes. It is also likely that athletes entering a college sport have their iron status screened or are supplemented by a coach or health care professional. The major issue with these studies was that the athletes came from all different sports, which can have a huge impact on the researcher’s results. In the future several studies should be completed but including only one sport in each study. In addition the duration, intensity and whether or not it is peak season for that sport should be included, also a more specific diet and whether or not they are menstruating. Supplementation of both types of athletes has not been discussed enough to give a concrete recommendation, dosage varies on the type of athlete, dietary intake and intensity of the sport. If ferritin levels are above 12ug/L and saturation of transferrin is above 16% supplementation is unnecessary. (1) But if the athlete has values below that, a supplement may be offered but should be given by a health care professional. As mentioned above depending on the intensity of the exercise supplements can range anywhere from 18 mg up to 160 mg (11) a dosage too high can cause cramps, dark stools, may compete with other minerals for absorption, and can be toxic to the liver. In addition a ferritin level over 150 ug/L is highly associated with coronary problems. E. Reference List 1. Rowland TW, Stagg L, Kelleher JF. Iron deficiency in adolescent girls. Journal of adolescent health. 1991; 12: 22-25. 2. Chatard JC, Mujika I, Guy C, Lacour JR. Anemia and iron deficiency in athletes. Sports Med. 1999; 27: 229-240. 3. Braun WA, Flynn MG, Carl DL, Carroll KK, Brickman T, Lambert CP. Iron status and resting immune function in female collegiate swimmers. IJSNEM. 2000; 10: 425-433. 4. Spodaryk K, Czekaj J, Sowa W. Relationship among reduced level of stored iron and dietary iron in trained women. Physiol. Res. 1996; 45: 393-397. 5. Rozenweig PH, Volpe SL. Effect of iron supplementation on thyroid and hormone levels and resting metabolic rate in two college female athletes: a case study. IJSNEM. 2000; 10: 434-443. 6. Malczewska J, Racynski G, Stupnicki R. Iron status in female endurance athletes and in non-athletes. IJSNEM. 2000; 10: 260-276 7. Risser WL, lee EJ, Poindexter B, West MS, Pivarnik JM, Risser JM, Hickson JF. Iron deficiency in female athletes: its prevalence and impact on performance. Ms-se. 1998; 20: 116-121. 8. Ashenden MJ, Martin DT, Dobson GP, Mackintosh C, Hahn AG. Serum ferritin and anemia in trained female athletes. IJSNEM. 1998; 8: 223-229. 9. Santolo MD, Stel G, Banfi G, Gonano F, Cauci S. Anemia and iron status in young fertile non-professional female athletes . Eur J Appl Physiol. 2008; 102: 70-3-709. 10. Williford H, Olson M, Keith RE, Barksdale JM, Blessing DL, Wang NZ, Preston P. Iron status in women aerobic dance instructors. IJSNEM. 1993; 3: 387-397. 11. Magazanik A, Weinstein Y, Abarbanel J, Lewinski U, Shapiro Y, Inbar O, Epstein S. Effect f an iron supplement on body iron status and aerobic capacity of young training women. Eur J Appl Physiol. 1991; 62: 317-323.