Archive for August, 2017

Intermittent fasting could help tackle diabetes – here’s the science

By Alison Major, on 29 August 2017

Today’s guest post is by Nicholas Lesica, Wellcome Trust Senior Research Fellow at UCL and author of A Conversation about Healthy Eating. This article was originally published on The Conversation. Read the original article.File 20170810 27661 18ax5ba
iordani/shutterstock

Nick Lesica, UCL

Intermittent fasting is currently all the rage. But don’t be fooled: it’s much more than just the latest fad. Recent studies of this kind of fasting – with restricted eating part of the time, but not all of the time – have produced a number of successes, but the latest involving diabetes might be the most impressive yet.

The idea of intermittent fasting arose after scientists were wowed by the effects of constant calorie restriction. A number of studies in many different animals have shown that restricted eating throughout adulthood leads to dramatic improvements in lifespan and general health.

The reasons for these improvements aren’t yet clear. Part of it seems to be that going without food gives cells in the body a much needed break to perform maintenance and repair. But the lack of food also forces cells to resort to alternative sources of energy. Some of these, such as ketones – molecules created in the liver from recycled fat – appear to be beneficial.

‘Fasting’ without fasting

The problem is that constant calorie restriction isn’t practical: it’s easy for scientists to impose upon lab animals, but hard for humans to impose upon themselves in the real world. Fortunately, we’ve learned that constant calorie restriction isn’t really necessary. Intermittent fasting seems to have many of the same benefits.

There are two main types of intermittent fasting. One type, known as “time restricted feeding”, requires eating only during a few hours of the day – say between 10am and 6pm. This approach gives the body a long break from food each night, and also reinforces beneficial circadian rhythms.

The other type of intermittent fasting – made popular by the 5:2 diet – is known as “periodic fasting”. This approach involves alternating between long periods of unrestricted eating and short periods of eating very little (five days of eating normally, two days of eating restricted calories).

It isn’t yet clear whether one type of intermittent fasting is better than the other. But the data so far suggest that both types can work.

Tackling diabetes in mice and men

The recent studies of the effects of intermittent fasting on diabetes have focused on periodic fasting in particular. As a first step, researchers led by Valter Longo at the University of Southern California, began by testing whether periodic fasting could cure diabetes in mice. They used mutant mice that lack the fat hormone leptin to regulate their food intake. These mice constantly overeat and become obese and diabetic in early adulthood.

The researchers found that after just a few months of periodic fasting – alternating seven unrestricted eating days with four restricted days – the diabetes was cured. This is an amazing result. But what’s even more amazing is the reason behind it.

The mice lost weight during the periodic fasting, which helped of course. But that wasn’t the whole story. Periodic fasting actually solved the problem directly at one of its sources: the pancreas.

Diabetes is a disease characterised by excess blood “sugar”, which really means excess blood glucose. It’s largely an insulin problem. Normally, insulin causes cells in the body to take in glucose from the blood. But with diabetes, glucose stays in the blood because cells no longer take it in. This is partly because many cells lose their sensitivity to insulin, but also because the pancreas stops making it.


Glucose meter, healthy lifestyles and nutrition.
ratmaner/shutterstock

It turns out that the periodic fasting made the pancreas start producing insulin again. The days of restricted eating gave the pancreas a break that allowed it to remove and recycle many of its cells. Then, when the mice started eating again, new cells that were capable of producing insulin emerged.

So the pancreas actually shrunk during the four restricted eating days, and regrew during the seven unrestricted eating days. After several such cycles of shrinking, recycling, and regrowing, the pancreas was nearly as good as new.

The big question, of course, it whether intermittent fasting will have the same effects in humans. The answer is not yet clear, but the initial indications from a recently published phase two clinical trial, again led by Longo, are promising.

In this study, 100 people went through a series of 30-day cycles of periodic fasting, each with 25 days of unrestricted eating and five days of restricted eating. After only three cycles, those subjects who started the trial with high blood sugar saw big improvements. And, importantly, none of the subjects in the trial experienced any harmful effects.

So the evidence in support of intermittent fasting keeps growing. Does that mean that we should all be doing it? Not necessarily.

Intermittent fasting seems to be most beneficial for those who are already overweight and unhealthy. While it does also seem to have some benefits for lean and healthy lab animals, it’s not yet clear whether the same is true for humans.

The ConversationA much larger phase three trial of intermittent fasting in humans that will clarify a lot of things is set to begin soon. The results will no doubt be very exciting.

Arcticness as a home

By Alison Major, on 16 August 2017

Today’s excerpt, is from the Editorial Introduction of Arcticness, a multi-contributor volume edited by Ilan Kelman, UCL .

People and communities, lives and livelihoods. These define the Arctic, just as with all other populated areas on the planet. Is there, then, anything special, specific, exceptional or unique about the Arctic? To the peoples in the Arctic, the answer is ‘of course’.

Because it is home.

As Arctic literature is fond of stating, there is no single Arctic. Definitions abound, from being a region or place to being an idea or phenomenon. The Arctic is delineated by latitude, tree lines, national and subnational borders and indigenous territories, among many other suggestions. All these elements vaguely concentrate into the northern areas of Canada, Finland, Norway, Russia and Sweden along with all of Alaska, Greenland and Iceland.

This is the Arctic as a place – and the Arctic as place. The Arctic is also characterised, perhaps more so, by its people. Depending on where boundaries are set exactly, the Arctic’s population is anywhere from approximately 4  million to approximately 13  million people. About 10 per cent of Arctic inhabitants are indigenous, belonging to 40 different groups, examples of which are Saami, Inuit, Nenets, Yakuts and Aleuts. In some jurisdictions, such as Nunavut and Greenland, indigenous peoples are the majority. All Arctic areas have comparatively low population density.

Arctic indigenous peoples are partly defined by the way in which they were colonised from the south. Iceland is the only Arctic country without designated indigenous peoples. The other seven countries have never fully addressed their post-colonial legacy which included active suppression of indigenous languages and cultures, forcing nomadic peoples to settle, and taking indigenous children away from their families for the purpose of ‘education’ and ‘acculturation’.

As part of aiming to re-connect Arctic peoples and places, and to redress past mistakes, each post-colonial Arctic country apart from Russia has, to a large degree, settled land claims with Arctic indigenous peoples. The settlements occurred in different ways and in different time periods, with implementation, monitoring and enforcement still not fully functional in many instances.

The generational context adds complexity. The generation of leaders who grew up under colonialism and who negotiated the settlements are now in the process of retiring. They are giving way to a new generation of leaders who did not experience similar difficulties or frontline fights for autonomy and the recognition of indigenous cultures. They face other challenges, such as low educational attainment, high rates of substance use and abuse, and high suicide rates.

They are also looking to connect to the world beyond their (mis) governing state through the internet and social media to define and re-define, and to be proud of, their indigeneity, their peoples and their places; that is, their Arctic. The battles are not over. Greenland’s independence is still a possibility. Racism against indigenous peoples remains. The peoples are not homogeneous groups, such as the Saami who have different livelihoods including reindeer herding, fishing, both and neither.

Non-indigenous Arctic peoples also represent the Arctic, not just Icelanders but also those born and/or living in the north but without an Arctic indigenous heritage. One class of Arctic peoples, most notably in Scandinavia, comprises immigrants from around the world, including refugees, who fully settled in the Arctic and who are now raising first-generation, Arctic-born families with diverse, international heritages.

Within this Arctic rainbow, what is the Arctic? How do Arctic peoples relate to their places? The ways include living, livelihoods, environments and movements. In many locales, movement means the typical commute by private or public transport to a nine-to-five office job. In many locales, it is the typical subsistence hunting, conversing with the wind, feeling the sea, traipsing the land and traversing the ice.

Water (solid and liquid) and wind flow, bringing with them life and death. The Arctic peoples flow with them. Movement, survival and thriving are choreographed within the elements and within the colours of the seasons:  blue, grey and white melding with brown, green and splashes of colour in summer flora and fauna. The ever-changing kaleidoscope of weather and skies, of animals and oceans, of plants and the Earth, creates Arctic flows and ebbs.

Transitions and boundaries are prominent but fuzzy. Snow melds into land shifts to water becomes ice, drifting lazily under the dazzling dome of the summer sun and the scintillating stars of the wild winter. When the ice roads thaw making transport difficult, inland communities are spoken of as being landlocked. When the ocean is too rough for boats and the wind is too dangerous for planes, island communities are seen as being entrapped.

What vocabulary suggests being icelocked? The ice can be too thin on the water or too crevassed on the land, or just too slushy everywhere. The transition between seasons can be harsh when the land ice and sea ice mixtures do not permit safe transport. Then, one’s Arctic place becomes evident, as an islander or not, as someone who enjoys being indoors or not.

Movement and entrapment mean that Arctic placeness is not contentedly fixed. In any case, the glaciers, the ice, the snow, the water and the wind are always in motion. The rivers and the seas emote ripples and waves. The tides breathe for the water and the wind for the air. Coasts erode and accrete – with both ice and sediment.

Arctic changes are expressed in other ways. From colonisation to self-determination, the Saami have created their parliaments, referenda supported autonomy for Greenland and Nunavut, and Russian regions and territories have various levels of self-governance. Exceptionalism identifies many Arctic place traits – including the internationally unique Svalbard Treaty and the central Bering Sea having its ‘donut hole’ which is an enclosed polygon of international waters surrounded by territorial seas.

The scale of Arctic territories is sometimes forgotten. From Murmansk to Chukotka, the time difference across Russia is nine hours. Alaska has only two time zones, an artificial construction, but as the largest American state more than twice the area of its nearest rival, it is almost as wide and as tall as the entire contiguous states. Ottawa– Iqaluit flights travel more than three times as far as the London– Edinburgh route and are still shorter than Greenland’s full north–south distance.

Current national borders across the Arctic are poorly reflective of indigenous cultures. The Saami are partitioned among four countries. Only modern politics draw a line between Alaska and Yukon. The Canada–Denmark dispute over Hans Island is meaningless for peoples who use the land, sea, ice and wind to live.

Many of these Arctic placeness discussions are characterised by islands and archipelagos including the Aleutians, Hans Island, Greenland, Iceland and Svalbard. Nunavut’s capital sits on Baffin Island rather than the mainland. Many of Norway’s principal Arctic settlements are on islands including Tromsø, Harstad and Hammerfest.

Island studies has evolved over the past generation, exploring the natures and personalities of islands, island communities and islanders. Much debate and critique has centred around what it means to be an island or an islander, defining and examining the essence of islandness. These and similar questions and explorations have emerged for the Arctic, Arctic communities and Arctic peoples.

Thus, we generate and query the term Arcticness through the chapters in this book.

Win a copy of A Conversation about Healthy Eating with Goodreads!

By Alison Major, on 10 August 2017

To the launch of A Conversation about Healthy Eating, we’ve teamed up with Goodreads to offer avid readers the opportunity to win one of five copies! To enter, use the line below [free membership required].

Goodreads Book Giveaway

A conversation about Healthy Eating by Nicholas Lesica

A Conversation about Healthy Eating

by Nicholas Lesica

Giveaway ends September 19, 2017.

See the giveaway details
at Goodreads.

Enter Giveaway

Losing weight without a diet: manipulating a type of brain cell gets results in mice

By Alison Major, on 2 August 2017

Today’s guest post is by Nicholas Lesica, Wellcome Trust Senior Research Fellow at UCL and author of A Conversation about Healthy Eating. This article was originally published on The Conversation. Read the original article.

File 20170727 27682 1wo3mnt
Evidence for a link between obesity and brain inflammation is getting stronger.
Suzanne Tucker/Shutterstock

Nicholas A Lesica, UCL

A new study has found something remarkable: the activation of a particular type of immune cell in the brain can, on its own, lead to obesity in mice. This striking result provides the strongest demonstration yet that brain inflammation may be a cause, rather than a consequence, of obesity. It also provides promising leads for new anti-obesity therapies.

The evidence linking brain inflammation to obesity has been building for some time. Consistent overeating causes stress and damage to cells in the body and brain. This damage results in a response from the immune system that has a wide range of effects.

Some of these effects help to reduce the problems caused by overeating, but others seem to make things worse. For example, in the hypothalamus – the part of the brain that controls, among other things, eating and activity – inflammation causes problems such as leptin resistance that interfere with the regulation of body weight.

Computer Hope
The hypothalamus controls eating and physical activity.
stefan3andrei/Shutterstock

Leptin is a hormone that is released by fat cells and provides the brain with information about the amount of energy stored as body fat. Normally, neurons in the hypothalamus that are sensitive to leptin will use this information to regulate eating and activity as needed to maintain body fat within some desired range.

In obesity, however, these neurons become insensitive to leptin. As a result, they no longer trigger the decrease in hunger and increase in energy expenditure that are necessary to lose excess weight. This is why the vast majority of attempts by obese people to lose weight fail– inflammation causes the brain to fight against it every step of the way.

So brain inflammation clearly plays an important role in sustaining obesity. But could it also be one of the primary causes of obesity in the first place? The onset of brain inflammation coincides with the other changes that take place in the body and brain as a result of overeating and weight gain. But whether brain inflammation actually causes the development of obesity is not yet clear. The results of the new study, however, demonstrate that the activation of a particular type of brain immune cell, microglia, initiates a cascade of events that do indeed lead directly to obesity.

Manipulating microglia in mice

In the study, researchers at the University of California, San Francisco and the University of Washington performed experiments on mice. They found that altering the activity of microglia in the hypothalamus allowed them to control the body weight of the mice independent of diet.

The researchers began by testing the effects of reducing either the number of microglia or their level of activity. They found that both manipulations cut the weight gain that resulted from putting the mice on high-fat diet in half.

They then tested the effects of increasing the activity of microglia. They found that this manipulation caused obesity even in mice that were on a normal diet. This latter result is particularly surprising. The fact that obesity can be induced through microglia – rather than directly through neurons themselves – is an indication of how strongly the brain’s supporting cells can exert control over its primary functions.

Computer Hope
Obesity can be induced by manipulating microglia.
Janson George/Shutterstock

So artificial brain inflammation can cause obesity in mice. Of course, that doesn’t mean that natural, diet-induced brain inflammation does cause obesity in humans. But these new results suggest that this idea is worth taking seriously, particularly given that fact that potential solutions to the obesity crisis are in short supply.

The ConversationThis new study alone has already identified several possible targets for anti-obesity drugs. Intriguingly, one of the same drugs that was used in the study to decrease activity in microglia is also being tested in human cancer trials, so initial indications of its effects on body weight should be available soon. But either way, a deeper understanding of the role of brain inflammation will help to clarify the causes of obesity. And hopefully prompt ideas about how it can be avoided in the first place.

Nicholas A Lesica, Wellcome Trust Senior Research Fellow, UCL

This article was originally published on The Conversation. Read the original article.