Friday, August 30, 2013

Food addiction DOES exist: Sugar-laden junk activates the same region of the brain affected by heroin and cocaine (?)

The usual naive logic.  It would be more reasonable to say that cocaine mimics the brain effects of food

But the study didn't look at that anyway.  It is far more amusing.  They gave people food that is quickly absorbed and food that is slowly absorbed. They found that the brain activity associated with food eating was greater with the rapidly absorbed food.  What did they expect?  It was a bit like "discovering" that grass is green

It has long been disputed whether or not food can really be classed as addictive but new research has suggested that it really is.

Some experts believe that it is not appropriate to term food as 'addictive' as it is essential to life and not something that people can be weaned off.

But a new study has found that high sugar snacks activate areas of brain that are also stimulated by hard drugs such as cocaine and heroin.

The research, carried out by the Harvard Medical School, sought to understand why so many people who strongly desire to reach a normal, healthy weight are unable to do so.

Dr Belinda Lennerz, who led the study and reported on it in The Conversation, said a that in theory, weight reduction should be simple  - just cutting down on the number of calories consumed should be easy, yet most dieters continue to overeat.

Dr Lennerz and her colleagues wanted to know whether overeating was perpetuated by processed, tasty food, especially those with a high glycaemic index.

High glycaemic index foods include refined starches and concentrated sugar and cause a rapid rise and fall in blood sugar after consumption. This triggers hunger and sometimes irritability.

The study involved creating two milkshakes - one with a high, and one with a low glycaemic index.

The milkshakes were otherwise identical, with similar calories and taste.

The drinks were then given to 12 healthy, overweight men on different days and in random order.

Four hours after the high glycaemic index shake, participants were hungrier than those who had consumed the low glycaemic index shake.

Experts also carried out functional MRI imaging on all participants.  The images revealed intense activation of the nucleus accumbens, a critical brain area in the dopaminergic, mesolimbic system that mediates pleasure eating, reward and craving.

Similar activation patterns have been found in people after consumption of addictive substances, such as heroin and cocaine.

Dr Lennerz said that their findings 'provide qualified support for the possibility of food addiction'.

She added: 'While food is necessary for life, we eat for reasons beyond our daily energy needs. When overeating becomes a pattern that is hard to break, we say someone is "addicted" to food.'

Finally Dr Lennerz concluded that while more research is needed to examine the concept of food addiction, 'the fact that a food may affect addiction centres in the brain, independent of calories or pleasure, provides the basis to rethink current dietary recommendations'.

Effects of dietary glycemic index on brain regions related to reward and craving in men

Lennerz BS et al.


Qualitative aspects of diet influence eating behavior, but the physiologic mechanisms for these calorie-independent effects remain speculative.

We examined effects of the glycemic index (GI) on brain activity in the late postprandial period after a typical intermeal interval.

With the use of a randomized, blinded, crossover design, 12 overweight or obese men aged 18-35 y consumed high- and low-GI meals controlled for calories, macronutrients, and palatability on 2 occasions. The primary outcome was cerebral blood flow as a measure of resting brain activity, which was assessed by using arterial spin-labeling functional magnetic resonance imaging 4 h after test meals. We hypothesized that brain activity would be greater after the high-GI meal in prespecified regions involved in eating behavior, reward, and craving.

Incremental venous plasma glucose (2-h area under the curve) was 2.4-fold greater after the high- than the low-GI meal (P = 0.0001). Plasma glucose was lower (mean ± SE: 4.7 ± 0.14 compared with 5.3 ± 0.16 mmol/L; P = 0.005) and reported hunger was greater (P = 0.04) 4 h after the high- than the low-GI meal. At this time, the high-GI meal elicited greater brain activity centered in the right nucleus accumbens (a prespecified area; P = 0.0006 with adjustment for multiple comparisons) that spread to other areas of the right striatum and to the olfactory area.

Compared with an isocaloric low-GI meal, a high-GI meal decreased plasma glucose, increased hunger, and selectively stimulated brain regions associated with reward and craving in the late postprandial period, which is a time with special significance to eating behavior at the next meal.


Violent video games such as Grand Theft Auto DON'T harm children - and could actually be therapeutic, claim experts

This is an old chestnut and the conclusions are familiar but evidence will never stop the mouths of attention -seekers and do-gooders like the nasty little baroness Greenfied

Playing violent video games such as Grand Theft Auto and Mortal Kombat do not harm children and could actually be therapeutic, according to a new study.

Even in children with attention deficit hyperactivity disorder (ADHD) or depression, researchers found there was no evidence to suggest the games had a negative effect upon their personality.

The findings contradict suggestions that violent video games can contribute to bullying, physical fighting, criminal assaults and even murder.

Clinical psychologist Dr Ferguson studied 377 children, who had an average age of 13 and who were suffering some form of elevated attention deficit or depressive symptoms, to see if violent video games made them more angry or aggressive.

His team at Stetson University, Florida, found that there was 'no evidence that violent video games increase bullying or delinquent behaviour among vulnerable youth with clinically elevated mental health symptoms.'

Instead they found that in some cases playing the violent games was cathartic, helping to reduce their aggressive tendencies and bullying behaviour.

The results, published in Springer’s Journal of Youth and Adolescence, reflect a recent report by the American Secret Service which linked aggressiveness and stress with youth violence rather than playing violent video games.

However the question remains whether the games play a role in the most appalling cases of youth violence, like that of Sandy Hook where 28 women and children were murdered by 20-year-old military game fan Adam Lanza.  Mr Lanza reportedly spent hours each day on video games including Call of Duty.

The general results of their study could not be used to explain these extreme cases explained Dr Fergusson.

He said: 'Statistically speaking it would actually be more unusual if a youth delinquent or shooter did not play violent video games, given that the majority of youth and young men play such games at least occasionally.'


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