Citation: Roest, M, van der Schouw, Y., de Valk, B., Marx, J., Tempelman, M., Groot, P., Sixma, J., and Banga, J. (1999). “Heterozygosity for a Hereditary Hemochromatosis Gene Is Associated With Cardiovascular Death in Women”. Circulation, 100(12), pp. 1268-1273. doi: 10.1161/01.CIR.100.12.1268
Summary By: Alexandra Pounds
Image Credit: Wikimedia Commons
- Big Picture: People with hemochromatosis (a genetic condition that can lead to iron overload) are at a higher risk for cardiovascular disease, especially if they smoke or have hypertension.
- Hemochromatosis is caused by a heterozygous gene HH, which affects how the body uptakes iron. People without this gene are able to regulate how much iron is absorbed from the diet, whereas people with this gene uptake too much iron.
- 12,239 Dutch women aged 51-69 were followed for 16-18 years. The women were tested for the heterozygous gene HH.
- The researchers accounted for age, smoking, obesity, and hypertension using statistics.
- Women with the heterozygous gene HH were more likely to die from cardiovascular disease, even when the researchers accounted for age, smoking, obesity, and hypertension.
- Women with the heterozygous gene HH who also smoked or had hypertension were even more likely to die from cardiovascular disease.
- Hemochromatosis may increase the risk of cardiovascular disease because hemochromatosis leads to iron overload. Iron can lead to LDL peroxidation, which can increase clogged arteries (which leads to cardiovascular disease).
- Because smoking also causes oxidative stress (more oxidation in the body), it can compound the risk for cardiovascular disease in the same ways.
- Limitations: This study did not examine women with hemochromatosis who died from causes other than cardiovascular disease. Maybe hemochromatosis is also linked to an increase risk of cancer? It’s not possible to say from this study.
Citation: Wirth, J., Lohman, T., Avallone, J., Shire, T., and Boileau, R. (1978). “The effect of physical training on the serum iron levels of college-age women.” Medicine and Science in Sport, 10(3), pp. 223-226.
Summary By: Alexandra Pounds
Image Credit: Aviano Airbase
- Big Picture: Short-term exercise does not affect Serum Iron levels in college-age women.
- Seventeen women exercised 3 times per week for 10 weeks on a bicycle at about 70% of their maximum heart rate for 20-25 minutes. An additional 8 women were used as a control group.
- The researchers measured: hemoglobin (Hb), hematocrit (Hct), serum iron (SeFe), and maximum oxygen uptake (Vo2 max)
- hemoglobin (Hb): no difference
- hematocrit (Hct): no difference
- serum iron (SeFe): no difference
- maximum oxygen uptake (Vo2 max): increased by 11% in the exercisers.
- When researchers accounted for whether or not the women were menstruating or using oral contraception, it made no difference to the results.
- Limitations: this trial was only for 10 weeks, which is considered short-term. We cannot say what happens to serum iron levels in women who exercise long-term.
Citation: Linos, E., Willett, W., Cho, E., Colditz, G, and Frazier, L. (2008). “Red Meat Consumption during Adolescence among Premenopausal Women and Risk of Breast Cancer” Cancer Epidemiology Biomarkers & Prevention, 17(8), pp 2146-2151. doi: 10.1158/1055-9965.EPI-08-0037
Summary by: Alexandra Pounds
Image Credit: Max Pixel
- Big Picture: Teens who eat a lot of well-done or fried red meats, especially processed meats or meats with additional hormones, may be at a greater risk of breast cancer.
- Over 39,000 premenopausal women reported how frequently they ate 142 different types of food from 1998 to 2005.
- 455 of these women got breast cancer.
- Researchers defined “red meat” as pork, beef, lamb, and processed meats (like hotdogs, meatloaf, and cured meats).
- Researchers found that:
- red meat consumption during adolescence was correlated with breast cancer. For every 100g of red meat (about one burger patty) consumed each day, the risk of breast cancer increased by 20%.
- red meat consumption during adulthood was NOT correlated with breast cancer.
- processed meats were associated with a higher risk of breast cancer compared to other meats.
- The processing of the meat, rather than the meat itself, may have played a role in breast cancer risk.
- Limitations of the study:
- Researchers also found that women who ate more red meat were also more likely to be smokers, have a higher BMI/caloric intake, and gained more weight during adulthood. These factors may have played a role in contributing to breast cancer risk.
- Red meat was not differentiated by how it was cooked. The researchers didn’t know how the women’s meat was cooked. Another study showed that well-done and fried meats quadrupled the risk of breast cancer. In this study, it may have been that those who developed breast cancer and eating more meat were eating more well-done or fried meats.
- The study required that some adult women recall the foods they ate when they were a teenager. They may have not remembered accurately.
- The women in the study were teens during the 1960’s and 1970’s, before hormone use in livestock was limited. The women eating more red meat may have developed breast cancer because of the hormones in the red meat rather than because of the red meat itself.