It appears that the type of fat that accumulates around the hips and bottom may offer some protection against diabetes.

Experts know that fat that collects in the abdomen, known as visceral fat, can raise a person's risk of diabetes and heart disease, whereas people with pear-shaped bodies, with fat deposits in the buttocks and hips, are less prone to these disorders.

Visceral and subcutaneous fat have major genetic differences and differ in their exposure to various hormones and growth factors and in their nutrient and oxygen supply.

The subcutaneous fat which collects under the skin possibly helps to improve sensitivity to the hormone insulin, which regulates blood sugar and may be actively protecting people from metabolic disease.

According to Dr. Ronald Kahn who led the research, mice given transplants of this type of fat deep into their abdomens lost weight and their fat cells shrank, even though they made no changes in their diet or activity levels.

Dr. Kahn says surprisingly it had a beneficial effect especially when it was placed inside the abdomen.

Dr. Kahn says initially the study aimed to find out why fat located in different parts of the body seems to have different risks of metabolic disease such as diabetes so they conducted a series of experiments on mice where they transplanted subcutaneous fat from donor mice into the bellies and under the skin of mice.

Mice that were given subcutaneous fat transplanted into their bellies started to slim down after several weeks, and also showed improved blood sugar and insulin levels compared to mice that underwent a sham procedure.

Dr. Kahn says this is an important result because not only does it say that not all fat is bad, but it points to a special aspect of fat where more research is needed.

The team are trying to find the substances produced in subcutaneous fat that provide the benefit as this could lead to the development of new drugs which mimic this effect.

Kahn says none of the known hormones appeared to be involved in this process and their findings suggest that there is some good fat.

The study is published in the current issue of Cell Metabolism.

The thesis also shows that the bacteria in the oral cavity are very important to the process of nitrates in food protecting the stomach's mucous membrane. This has been examined in that rats have been given nitrate-rich feed, whereby some of them have also simultaneously received an antibacterial oral spray. When these rats were then given anti inflammatory drugs, damage to the mucous membrane only occurred in the ones that had received the oral spray. In the latter the nitrates no longer had a protective effect on the mucous membrane, as the oral spray had killed the important bacteria that normally convert nitrates into nitrites.

"This shows how important our oral flora is. The fact that these bacteria are not just involved in our oral hygiene but also play an important role in the normal functions of the gastrointestinal tract is not entirely new. It is currently an important issue, as antibacterial mouthwashes have become more and more common. If a mouthwash eliminates the bacterial flora in the mouth this may be important to the normal functioning of the stomach, as the protective levels of nitric oxide greatly decrease," says Joel Petersson.

In his opinion the research results also provide a new approach to the importance of fruit and vegetables in our diet.

"If we followed the National Swedish Food Administration's recommendation and ate 500 g of fruit and vegetables per person per day it would definitely be better for our stomachs.

Joel Petersson's thesis is being scrutinised at Uppsala University on 9 May.

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