Researchers have identified a DNA mutation common in animals that may explain why a diet high in carbohydrates induces obesity and diabetes in some but not others.
The study, published in the journal PLOS Genetics, showed a surprising difference between two sets of the fruit flies when feeding with alternate diets high in protein and high in carbohydrates.
Fruit fly larvae with a noted mitochondrial DNA (mtDNA) mutation showed a pronounced increase in development when eating high carbohydrate diet of banana, but stagnated on a high protein diet of passion fruit, Xinhua news agency quoted the study as saying.
Conversely, fruit fly larvae without that mutation thrived on the high protein diet, but dropped in frequency when put on carbohydrates, the report said.
The six-year collaborative study by Australian, American and Spanish researchers challenged the neutral theory of molecular evolution in which changes in species at the molecular level are random, not caused by natural selection and provide no benefit or disadvantage to the species.
According to lead author Bill Ballard from the University of New South Wales, the research was a rare demonstration of positive selection at work in evolution.
Given that humans share 75 per cent of the same genes as fruit flies, and have the same mtDNA genes, it is likely, according to the study, that the same mutation inherited in human mtDNA may metabolise carbohydrates in a similar way.
“But, the news is not all bad for people harbouring the mutation,” said Ballard.
“You would need to manage your carbohydrate intake when you are younger, but if you are unfortunate enough to develop Parkinson’s Disease, a high carbohydrate diet will help you maintain weight,” Ballard added. (IANS)
The sound of the word ‘Cancer is enough to scare anyone because there is no definite cure for it. Pancreatic cancer is one of those cancers in which the overall survival is very bleak as cases are often less sensitive to chemotherapy and radiotherapy. Dr Pradeep Jain, GI Oncosurgery, Medical Oncology, Fortis Hospital, Shalimar Bagh informs you about the connection between obesity and Pancreatic Cancer.
The best method to decrease the mortality (death rate) of these cancers is to either catch them early or prevent them happening. In view of non-availability of any screening test and limitation of diagnostic test, it is almost impossible to catch them very early. As dietary modification has been known for a long time to prevent cancer, it is likely to work in case of pancreatic cancer also.
Pancreatic cancer is associated with obesity and fat consumption as suggested in many epidemiological studies. Consumption of fat has been linked to pancreatic cancer not only directly but also by causing obesity. In obesity there is a general increase in inflammatory conditions in the body which leads to release of some chemicals (cytokines) which have important role in creation of pancreatic cancer.
Fat consumption (mainly saturated fats) have been shown to increase cancer of the pancreas by many observational studies in last 2 decades. In fact a study published (which comprised of more than half million US adults) in journal of the National Cancer Institute in 2009 demonstrated a positive association between dietary intake of total fat, particularly from animal sources. When people taking highest of fat compared to people taking lowest of fat, they are 23 per cent more likely to be diagnosed with pancreatic cancer (the effect was more profound when intake of saturated fat was more).
It is very difficult to comment how does fat consumption lead to pancreatic cancer, but it is likely that fat stimulates the release of an important hormone CCK (Cholecystokinin) for biliary and pancreatic secretion. And this hormone is an important instrument in the growth of pancreatic cancer cells.
In fact, in an experimental study, the antagonist of CCK, Proglumide has shown to decrease the growth of cancer cells and decrease metastasis (spread) potential of cancer.
Now this leads to an important question whether with diet modification (by reducing content of fat) is it possible to decrease the chances of pancreatic cancer? A recent study published in Nov 2017 issue of AICR’S cancer research update) have found that older women who are overweight or obese had lowered the risk of getting pancreatic cancer by following a low fat diet plan.
Some were arranged to eat less fat and more vegetables, fruits and grains (the intervention group) other followed their normal diet (the comparison group). After 15 years of follow up, 92 cases of pancreatic cancer were identified in the intervention group and 165 in the comparison group. This translates to a rate of 35 cases per 100,000 in the intervention group and 41 per 100,000 in the comparison group.
Low fat diet was particularly effective in reducing cancer risk in over weight and obese post-menopausal woman. A low fat diet was not found to lower the disease risk for women whose weight was normal.
Though these evidences support that high fat consumption may increase the chances of pancreatic cancer and by reducing the fat consumption the incidence of cancer may decrease, but these cannot be considered as very strong evidence to support a ‘cause and effect’. But this can be considered at least a caution to decrease fat (particularly animal fat) consumption in diet.
Foods that are sources of saturated or trans fats are butter, margarine (stick), coconut oil, palm oil, vegetable oil and hydrogenated oil. We should motivate the general public to consume more of fibre and exercise and reduce saturated fat content from diet. (IANS)