A latest research paper shows a diet low in nutrients might help increase the lifespan of humans.
The research conducted on laboratory animals argues that dietary restrictions can result in higher rates of cellular recycling and repair mechanisms in the body. But, according to them, this effect evolved to help organisms during famines.
The authors explain that animals need less food for survival as the stored nutrients in the cells can be recycled and reused.
“This is the most intriguing aspect, from a human health stand point. Although extended lifespan may simply be a side effect of dietary restriction, a better understanding of these cellular recycling mechanisms that drive the effect may hold the promise of longer, healthier lives for humans,” said lead study author, Dr Margo Adler, an evolutionary biologist at UNSW Australia in a press release.
“This effect has been demonstrated in laboratories around the world, in species ranging from yeast to flies to mice. There is also some evidence that it occurs in primates,” Adler said
“But we think that lifespan extension from dietary restriction is more likely to be a laboratory artifact,” said Adler. She further explained that the most commonly believed theory is that this effect evolved to enhance the survival chances during times of famine.
The authors explained why no extension in lifespan is seen in the wild. This is because restricted diets lower the ability of the immune system to fight diseases and reduce the muscle strength necessary to defend against predators.
“Unlike in the benign conditions of the lab, most animals in the wild are killed young by parasites or predators,” Adler explained
“Since dietary restriction appears to extend lifespan in the lab by reducing old-age diseases, it is unlikely to have the same effect on wild animals, which generally don’t live long enough to be affected by cancer and other late-life pathologies,” she added.
The paper is published in the journal ‘BioEssays.’
A way of screening for ovarian cancer appears to detect the disease in early stages, and if confirmed in clinical trials, the test could become a routine screening for women.
In the study, researchers tested the screening on more than 4,000 women over an 11-year period. The women underwent yearly blood tests, and the researchers recorded the levels of a protein called CA-125, which is produced by the majority of ovarian tumors. Women who had sudden increases in CA-125 levels were referred to a gynecologist and were given an ultrasound.
On the basis of their ultrasound results, 10 women underwent surgery during the study period. It turned out that four women had ovarian cancers still in an early stage, and five others had ovarian tumors that were either benign, or of low malignant potential (tumors that may become cancerous, but usually do not). One woman had endometrial cancer, according to the study published today (Aug. 26) in the journal Cancer.
The study suggested that the testing strategy had a specificity of 99.9 percent, the researchers said, meaning that only 0.1 percent of patients without cancer would be falsely identified as having the disease.
Two women in the study turned out to have ovarian tumors that were not detected by the screening, but both were of low malignant potential, the researchers said.
“The results from our study are not practice-changing at this time; however, our findings suggest that using a longitudinal (or change over time) screening strategy may be beneficial in postmenopausal women with an average risk of developing ovarian cancer,” study researcher Dr. Karen Lu, professor of gynecologic oncology at the University of Texas, said in a statement.
Despite advances in treatment, ovarian cancer remains a highly lethal disease, mainly because most women with ovarian cancer are diagnosed when the disease is at a late stage. When caught at an early stage, 75 to 90 percent of patients survive at least five years, the researchers said.
There currently are no established screening tests for ovarian cancer. For a cancer screening test to be useful, it has to be sensitive enough to detect markers of the disease before symptoms manifest, while also being specific enough so that it doesn’t falsely suggest cancer in people who don’t have it.
Previous investigations have looked at whether measuring women’s CA-125 levels might be an effective way to screen for ovarian cancer, but too often, the test has not been found to be sensitive enough to detect all cases of the disease, and at the same time has found too many false positives (women who turned out not to have cancer).
The new strategy is different because it tracks changes in each woman’s levels of CA-125, instead of only looking for a CA-125 level that might be considered high based on the average of the entire population. “It’s more personalized, and it also incorporates age,” Lu told LiveScience.
One of the challenges to developing an effective ovarian cancer screening strategy for women in the general population is that the screening has to be highly specific, so that follow-up testing and surgery that turn out to be unnecessary are kept to a minimum.
“In breast cancer screening, when a mammogram is abnormal, a biopsy is made,” before anything further is done, Lu said. “But in ovarian cancer, in order to confirm cancer, an actual surgery is needed to take out the ovaries and examine them.”
“In order for this method to become a screening test, it has to pass the gold standard,” she said. “It has to show that in a large group of women who did the screening, there were fewer deaths from ovarian cancer compared to another group who didn’t get screened.”
The researchers are waiting for the results of a larger, randomized study currently being conducted in the United Kingdom that uses the same screening strategy. The results are scheduled to be released by 2015.
“If the results of this study are also positive, then this will result in a change in practice,” Lu said.
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Joslin Study Finds Connection Between Erectile Dysfunction and Cardiovascular Disease in Joslin Medalists
BOSTON – A number of studies have established the connection between erectile dysfunction and cardiovascular disease in men starting in their fourth decade of life. However, a new study at Joslin Diabetes Center that examined the connection between erectile dysfunction and cardiovascular disease in Joslin Medalists – people living with type 1 diabetes for 50 or more years –showed that a history of erectile dysfunction is independently associated with cardiovascular disease.
This suggests that sexual dysfunction can predict cardiovascular disease in those with type 1 diabetes for 50 or more years, but who are relatively free of microvascular diseases.
The primary and most commonly evaluated risk factors for cardiovascular disease associated with diabetes include dyslipidemia, elevated body mass index (BMI), poor glycemic control, hypertension, insulin resistance and a history of smoking.
The hypothesized cause found in previous studies that examine the relationship between sexual dysfunction and cardiovascular disease is that the vessels feeding the genitals are smaller than those feeding the heart and therefore show clinical symptoms earlier. The physiologic mechanism is endothelial dysfunction resulting from the inhibition of the nitric oxide cascade, thus preventing the dilation of the arteries impairing blood flow imperative for rigidity.
“In general, the vessels involved in erectile dysfunction have a smaller diameter, and tend to be affected by mechanisms of endothelial dysfunction earlier than larger vessels found in the heart, so this could be a predictor of cardiovascular disease,” explained the author Sara Turek, study coordinator for the Medalist program at Joslin.
During the Joslin study, approximately 300 males were examined and completed questionnaires as part of the Medalist Study including a question regarding sexual dysfunction.
Seventy percent of males in the study reported experiencing sexual dysfunction over their lifetime. Factors correlated with the sexual dysfunction were higher levels of A1C, BMI, cholesterol and increased levels of IL6, an inflammatory marker. The more significant results from this study demonstrated that sexual dysfunction is associated with cardiovascular disease without being mediated by other identified risk factors.
“If [sexual dysfunction] is an overt problem that drives a man to go to the doctor, it should clue the doctor to take a look at some possible cardiovascular symptoms before anything major and life threatening arises,” said Turek.
A distinctive aspect of this study was that it was the first time sexual dysfunction was examined in such a large group of men who have lived with type 1 diabetes for an extended amount of time.
“The age of this group is interesting,” said co-author Stephanie Hastings, study coordinator for the medalist program at Joslin. “I think it will become more relevant as people continue live longer.”
Future plans for this study include possibly expanding the study to see if the results are consistent with a larger group of participants and following up with medalist participants in three or so years to see in their results have changed or stayed stable. Lastly, Turek and Hastings are also curious about exploring the connection between sexual dysfunction and cardiovascular disease in women.Joslin Diabetes Center and Joslin Clinic
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