People with apple-shaped figures have a higher risk of brain inflammation - but pears are safe, study says

Having an apple-shaped figure may raises the risk of inflammation in the brain, a study suggests.

People whose fat builds up around their abdomen have a higher risk of brain issues and diseases related to inflammation, the University of California, Riverside study found.

In contrast, pear shapes, whose weight gathers on their hips, thighs or buttocks, have a lower risk.

The authors found that, among healthy people, this risk of brain inflammation from belly fat is almost exclusive to men. They believe that women have evolved to have a lower risk because pregnancy inevitably causes them to build fat in their midriffs.

However, once a woman tips into the category of obesity, their risk sky-rockets.

Lead author Professor Djurdjica Coss, from the University of California, Riverside, said: 'My advice is: "Watch your diet!" And keep an eye on body weight, particularly around the abdomen.'

The researchers analysed three-week-old male mice. Like men, male rodents tend to store fat around their abdomens, creating an apple shape.

They also looked at female mice, who typically deposit fat around their hips, like women.

Some of the animals were fed a high-fat diet while others had a standard eating regimen.

Blood samples were collected from all the mice to determine how their diets affected their hormone levels.
Results suggest obese male rats store fat on their abdomens, creating an apple shape.

Such rodents also have higher levels of inflammation in their brains.

Obese female rats, however, store excess fat beneath their skin and have lower amounts of inflammation.

Professor Coss said: 'We know that abdominal fat - that is, fat around visceral organs - gets more inflamed with a fat overburden.

'This fat then recruits immune cells from blood circulation that get activated.'

In obese male mice, these immune cells even cross the blood-brain barrier, which usually protects dangerous substances from reaching the vital organ.

Professor Coss said: 'The brain has been considered an "immune protected site", but we show that peripheral inflammation "spills over" into the brain, which, in turn, may cause neuronal problems'.

Long term brain inflammation has previously been associated with damage to the organ.

As well as higher levels of inflammation, obese male mice are also more likely to develop metabolic syndrome than their female counterparts.

Metabolic syndrome occurs when a person has at least three of the following: abdominal obesity, high blood pressure, elevated blood sugar, high amounts of fat in their blood and high cholesterol.

Professor Coss said: ' Mice on high-fat diet develop metabolic syndrome - a constellation of pathologies that includes Type 2 diabetes and insulin insensitivity - similarly to obese humans.

'Obese men have lower testosterone levels, contributing to low libido, low energy, and reduced muscle strength. We see this in mice, too; obese male mice showed nearly 50 percent decreases in testosterone and sperm number.'

In addition, when female mice are fed the same high-fat diet as males, it takes them longer to gain weight.

This is thought to be due to female mice producing estrogen, which protects them from weight gain. Many women gain weight after the menopause due to a decline in this hormone.

When the researchers removed the rodents' ovaries to simulate menopause, the female mice did gain weight but did not experience the inflammation seen in obese males.

This suggests factors other than oestrogen may protect against the effects of obesity in female mice.

Yet, when the obese female animals continued to gain weight, their fat storage shifted on to their abdomens, making them apple shaped.

Professor Coss said: 'While overweight, women are more protected than men where inflammation is concerned.

'This protection is significantly curtailed when overweight women become obese and fat gathers around the waist.'

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