F.Y.I. —

Much of Our Fruit Is Imported.  Is That a Bad Thing?

Imports have increased steadily for decades, but the extent of the change may be surprising: More than half of the fresh fruit and almost a third of the fresh vegetables Americans buy now come from other countries.

Although local, seasonal and farm-to-table are watchwords for many consumers, globalization has triumphed in the produce aisle. And despite the protectionist “America First” message coming from the Trump administration, the growth in imports appears likely to continue.

So this is an apt moment to examine how the shift happened, and what it portends — good or ill — for American consumers and farmers.  Read more here, from The New York Times.

 

Researchers Discover Potential Source of Gender Differences in Migraines

Of the more than 38 million Americans who experience migraine headaches, 28 million are women. Compared to men, women also experience more frequent and severe migraines and don’t respond as well to drug treatments. Findings from a new study conducted in rats reveal that females may be more susceptible to migraines and less responsive to treatment because of the way fluctuations in the hormone estrogen affect cells in the brain.

Emily Galloway, an undergraduate research assistant in the laboratory of Tally Largent-Milnes in the Department of Pharmacology at the University of Arizona in Tucson, will present this research at the American Society for Biochemistry and Molecular Biology annual meeting during the 2018 Experimental Biology.

“Conducting research on the molecular mechanisms behind migraine is the first step in creating more targeted drugs to treat this condition, for men and women,” said Galloway. “Knowledge gained from this work could lead to relief for millions of those who suffer from migraines and identify individuals who may have better responses to specific therapies.”

The new study is one of the first to examine the role of the sodium proton exchanger NHE1 in migraine headaches. NHE1 regulates the transport of protons and sodium ions across cell membranes, including those that make up the blood-brain barrier. When NHE1 isn’t present at high enough levels or doesn’t function properly, it can cause increased pain signaling that leads to a migraine. Problems with NHE1 can also directly alter the ability of migraine drugs to cross the blood-brain barrier.

Even though women are much more likely to experience migraines than men, most migraine research is conducted using male animal models. In the new study, the researchers examined both male and female rats and found NHE1 expression levels were four times higher in the brains of the male rats. In the female rats, they observed that the highest estrogen levels corresponded with the lowest levels of NHE1 expressed in the endothelial cells that form the blood vessels in the brain.

“Based on our findings, we think that women are more susceptible to migraine because the larger magnitude sex hormone fluctuations lead to changes in NHE1 expression, which may leave the brain vulnerable to ion dysregulation and pain activation,” said Galloway.

The new work is part of an effort to create a molecular map of how sex hormones affect NHE1 expression. In the future, the researchers want to see if drugs that target certain players in this map would prevent dysregulation of NHE1 expression at the blood brain barrier. This could lead to new treatments for people who suffer from migraines.

 

Researchers Report Four New Insights into Diet and Health

What we eat plays a significant role in our health. The Experimental Biology 2018 meeting (EB 2018) will showcase new research into how diet could be used to fight cancer and how specific eating patterns can encourage weight loss.

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.

Adults who eat breakfast gain less weight

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.

 

Drinking Water May Help Exercising Seniors Stay Mentally Sharp

Older people should drink more water to reap the full cognitive benefits of exercise, new research suggests. The study, presented at the American Physiological Society (APS) annual meeting at Experimental Biology 2018 in San Diego, explores the association between hydration status before exercising and exercise-enhanced cognition in older adults.

Dehydration has been shown to impair exercise performance and brain function in young people, but less is known about its impact on older populations. “Middle-age and older adults often display a blunted thirst perception, which places them at risk for dehydration and subsequently may reduce the cognitive health-related benefits of exercise,” a team of New England-based researchers wrote.

The researchers recruited recreational cyclists (average age 55) who participated in a large cycling event on a warm day (78-86 degrees F). The cyclists performed a “trail-making” executive function test–quickly and accurately connecting numbered dots using paper and pencil–before and after the event. Executive function includes the skills needed to plan, focus, remember and multitask. Exercise has been shown to improve intellectual health, including executive function.

The research team tested the volunteers’ urine before they exercised and divided them into two groups–normal hydration and dehydrated–based on their hydration status. The normal hydration group showed noticeable improvement in the completion time of the trail-making test after cycling when compared to their pre-cycling test. The dehydration group also completed their post-cycling test more quickly, but the time reduction was not significant. “This suggests that older adults should adopt adequate drinking behaviors to reduce cognitive fatigue and potentially enhance the cognitive benefits of regular exercise participation,” the researchers wrote.

 

Why Zero-Calorie Sweeteners Can Still Lead to Diabetes, Obesity

Increased awareness of the health consequences of eating too much sugar has fueled a dramatic uptick in the consumption of zero-calorie artificial sweeteners in recent decades. However, new research finds sugar replacements can also cause health changes that are linked with diabetes and obesity, suggesting that switching from regular to diet soda may be a case of ‘out of the frying pan, into the fire.’

Artificial sweeteners are one of the most common food additives worldwide, frequently consumed in diet and zero-calorie sodas and other products. While some previous studies have linked artificial sweeteners with negative health consequences, earlier research has been mixed and raised questions about potential bias related to study sponsorship.

This new study is the largest examination to date that tracks biochemical changes in the body–using an approach known as unbiased high-throughput metabolomics–after consumption of sugar or sugar substitutes. Researchers also looked at impacts on vascular health by studying how the substances affect the lining of blood vessels. The studies were conducted in rats and cell cultures.

“Despite the addition of these non-caloric artificial sweeteners to our everyday diets, there has still been a drastic rise in obesity and diabetes,” said lead researcher Brian Hoffmann, PhD, assistant professor in the department of biomedical engineering at the Medical College of Wisconsin and Marquette University. “In our studies, both sugar and artificial sweeteners seem to exhibit negative effects linked to obesity and diabetes, albeit through very different mechanisms from each other.”

Hoffmann will present the research at the American Physiological Society annual meeting during the 2018 Experimental Biology meeting, held April 21-25 in San Diego.

The team fed different groups of rats diets high in glucose or fructose (kinds of sugar), or aspartame or acesulfame potassium (common zero-calorie artificial sweeteners). After three weeks, the researchers saw significant differences in the concentrations of biochemicals, fats and amino acids in blood samples.

The results suggest artificial sweeteners change how the body processes fat and gets its energy. In addition, they found acesulfame potassium seemed to accumulate in the blood, with higher concentrations having a more harmful effect on the cells that line blood vessels.

“We observed that in moderation, your body has the machinery to handle sugar; it is when the system is overloaded over a long period of time that this machinery breaks down,” Hoffmann said. “We also observed that replacing these sugars with non-caloric artificial sweeteners leads to negative changes in fat and energy metabolism.”

So, which is worse, sugar or artificial sweeteners? Researchers cautioned that the results do not provide a clear answer and the question warrants further study. It is well known that high dietary sugar is linked to negative health outcomes and the study suggests artificial sweeteners do, too.

“It is not as simple as ‘stop using artificial sweeteners’ being the key to solving overall health outcomes related to diabetes and obesity,” Hoffmann added. “If you chronically consume these foreign substances (as with sugar) the risk of negative health outcomes increases. As with other dietary components, I like to tell people moderation is the key if one finds it hard to completely cut something out of their diet.”

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