New research explores the role of diet in fighting cancer and how specific eating patterns encourage weight loss. The findings of the four studies were reported at The Experimental Biology 2018 meeting (EB 2018).
Time-restricted eating reduces tumor growth in mice
Obesity is known to increase the risk for breast cancer, particularly in postmenopausal women. With a long-term goal of developing practical strategies to curb breast cancer risk, researchers from the University of California, in San Diego, examined how restricting eating to a certain number of hours each day might affect cancer. For the study, obese mice modeling the postmenopausal life stage were either given access to high-fat food 24 hours a day or restricted to eating the high-fat food during 8 active hours, simulating daytime eating in people. After 3 weeks, the mice were injected with breast cancer cells. Although the overall quantity of food consumed differed little between the two groups, the time-restricted eating group showed reduced tumor growth as well as better glucose tolerance and insulin resistance, which are both linked to blood sugar control. Additional experiments showed that tumor growth was insulin-dependent, suggesting that time-restricted feeding may act by lowering insulin signaling.
Although studies have shown an association between eating breakfast and healthy body weight in children and teenagers, less research has focused on this relationship in adults. In an analysis involving 347 healthy adults, researchers from the Mayo Clinic found that study participants who skipped breakfast were more likely to be obese than those who ate it frequently, defined as five to seven times a week. Participants who skipped breakfast also had larger waists than those who ate breakfast frequently or infrequently (one to four times a week). The link between skipping breakfast and weight gain remained even after the researchers took into account age, gender and body mass index. People who did not eat breakfast reported the most weight gain over the past year, and those who consumed breakfast on most days reported the lowest weight gain. The researchers conclude that regularly consuming breakfast is important for maintaining a healthy weight at all ages.
Alternate-day fasting enhances weight loss in obesity-prone rats
When a person is losing or maintaining recently lost weight, energy expenditure during rest and activity tends to decrease as the body's metabolism gradually slows. In a new study, Kent State University researchers examined how alternate-day fasting -- a diet that restricts calories every other day -- affects energy expenditure. They placed lean and obese-prone mice on every-day calorie restriction or alternate-day fasting aimed at equivalent weight loss and then measured energy expenditure during treadmill walking. Although the obesity-prone and lean mice on both diets showed a similar decrease in activity-associated energy expenditure, the obesity-prone mice on the alternate-day fasting diet lost significantly more weight than the lean mice. There was also no difference in activity-associated energy expenditure on fasting and non-fasting days. The results suggest that weight loss effects from alternate-day fasting might also vary in people.
New insights into taste perception
Conditions inside the mouth such as temperature can affect our perception of taste. Interactions between taste and the general sensitivity of the mouth to pungency, irritation or heat were thought to result from indirect interactions between taste cells and neuropeptides such as calcitonin gene-related peptide (CGRP) and substance P. In a new mouse study, researchers from the Southern Illinois University School of Medicine used a combination of functional imaging and cellular biosensors to show that neuropeptides play a more direct regulatory role in processing taste signals. The study results suggest that substance P and CGRP act as inhibitory neurotransmitters that shape the signals traveling from taste buds to the brain. The discovery of this unanticipated route of taste sensory information flow could aid in the development of taste modifiers for potential use in managing obesity or new treatments for taste problems that develop as a side effect of chemotherapy drugs.