TOFI, what is that? A kind of new candy? Nope! TOFI stands for Thin on the Outside, Fat on the Inside.

Body mass index (BMI) has been used to define if someone is obese or not. Obese people are at increased risk of having heart disease, high blood pressure, diabetes, fatty liver and joint problems. We assume that slim people are healthier than those who are obviously overweight. However this might not be the case anymore! The reason is that many outwardly slim people are storing up dangerous layers of fat inside their bodies, especially in the abdomen and around the internal organs such as the liver and heart. Fat can also be stored within the liver and muscles. This type of fat is called visceral fat. The fat stored beneath the skin is called subcutaneous fat. Visceral fat is not visible from the outside. Doctors are now concerned about the health effects of excessive visceral fat.

A study from Verona, Italy looked at the plasma biomarkers of inflammation and endothelial dysfunction in 100 healthy, non-smoking male volunteers with or without fatty liver (Diabet Med 2005; 22: 1354 – 1358). Of these 100 individuals, 35 with fatty liver had markedly higher levels of biomarkers of inflammation and endothelial dysfunction when compared to those without fatty liver. They also had significantly higher values for BMI, diastolic blood pressure, triglycerides and visceral fat. By performing special statistical analysis of the results, they found that increased visceral fat content is the most significant factor in predicting the presence of increased plasma biomarkers of inflammation and endothelial dysfunction.

Using magnetic resonance imaging (MRI), researchers from Imperial College London, have been looking at the visceral fat content of people with different habitus. According to Professor J Bell, slim people, despite having a healthy BMI reading, can have an unhealthy amount of visceral fat inside their body. The average male has 5.4 litres of visceral fat while it is only 3.08 litres for women. However, women carry more fat overall because most of the fat is carried on the thighs as subcutaneous fat. The total amount of fat (visceral + subcutaneous fat) in the average woman is 37 litres vs 30 litres in a man. In Japan, sumo wrestlers have a BMI of 56 and eat up to 5,000 calories per day. MRI studies of the fat distribution in these wrestlers have shown that they have little visceral fat. Most of the fat is being ‘carried’ as subcutaneous fat. They have low cholesterol levels, low insulin resistance and low levels of fatty acids called triglycerides. In other words, despite their habitus, they do not have the metabolic syndrome. The researchers in Imperial College are now looking at the influence of different diets on visceral fat. People who consume starch in the form of lentils and pulses are likely to lay down less fat in the abdomen. Professor Bell and his team are doing a trial on healthy volunteers to see what happens to their visceral fat content when they switch to a diet high in grains and lentils. The result of this study would be of interest to all.

The fact that doctors are now looking at the role of visceral fat in health does NOT mean that obesity is not a health hazard. The point at which visceral fat is detrimental to health has not been clearly defined yet. What we do know is that obesity IS associated with many health problems. BMI is a good indicator to all as to what is healthy and what is not. Like a lot of things in medicine, a test or a measurement merely tells us the probability of an event occurring. It cannot be seen as an absolute – it is not 100%. For example, if you check the tumour marker for colon cancer, CEA, in the blood of 100 patients with colon cancer, you will find that the level is abnormal in about 80 of them. In 20 patients the CEA level will be within the normal range. Unlike physics or chemistry, medicine is different because the human body is a living thing. It is constantly ‘on the move’, influenced by multiple internal and external factors. In medicine, there are always exceptions to the rule.

Christmas is just round the corner and it is a time to be merry. Indulge yourself and have fun but don’t forget to put in some exercise and work off some of the excess calories as well.

Merry Christmas to all!

The recent news from London about Mr Litvinenko being poisoned by Polonium 210 (²¹⁰Po) read like a John Le Carre spy novel. I was intrigued more by the radioactive element ²¹⁰Po and its relevance to medicine. What surprised me when I performed a quick search on it was the information that tobacco contains ²¹⁰Po!

Polonium was discovered by Marie Curie, the famous Polish chemist, in 1898. Dr Curie isolated polonium and radium from pitchblende, a material that contains uranium. When she discovered polonium, she named it after her home country Poland (Latin: Polonia). She named it after Poland hoping that this would publicize the fact that Poland was not independent and was under the Russian, Prussian and Austrian partition. It was only in 1918, after WW1, that Poland became an independent country again.

During the decay of ²¹⁰Po to its final non-radioactive element lead (Pb 206), it produces the radioactive isotope ²¹⁰Pb as well. Thus, a smoker not only gets ²¹⁰Po into the lung, he or she also inhales ²¹⁰Pb. Poland has one of the highest populations of smokers in the world. A study from the University of Gdansk in Poland looked at the polonium content in the 14 most frequently smoked brands of cigarettes in Poland (J Environ Radioact 2001; 57: 221 – 230). These 14 brands accounted for > 70% of the cigarettes consumed in Poland. If you smoked 1 packet of cigarettes per day for one year, the mean annual effective dose of radiation you received would be 35 microSv from ²¹⁰Po and 70 microSv from ²¹⁰Pb. If you smoked two packets per day, the annual dose would be 471 microSv from both radioactive agents. What is the relevance of this?

The State of Washington Department of Health (DOH) has published a table on annual radiation dose limits for radiation exposure of workers and the general public. In it the DOH limit for members of the general public is listed as 0.0001 Sv / year. This is equivalent to 100 microSv per year. With our present knowledge, it is assumed that there is a risk of radiation–induced cancer no matter how low the radiation dose is; hence all radiation exposure is considered hazardous.

If you think only Polish cigarettes are affected, then think again! A very recent study from Athens, Greece examined the content of the two radionuclides, ²¹⁰Po and ²¹⁰Pb, in tobacco from 7 regions in Greece (J Environ Radioact 2006; 85: 94 – 102). They found variable amounts of the radionuclides from different regions of the country. They estimated that the mean annual effective dose of radiation received by a smoker who smokes one packet of cigarettes per day was 287 microSv. In Egypt, it is the same picture and the mean annual exposure was found to be 444 microSv (J Environ Radioact 2004; 71: 33 – 41). Cigarettes in Brazil are similarly ‘hot’ (J Environ Radioact 2002; 62: 115 119).

Every drag of the cigarette leads to more than 3000 types of noxious chemicals being inhaled into the lungs. If you happen to be standing next to a smoker, you get some of this into your lungs too! Now, you have to remember that you are also getting a dose of the radioactive elements, ²¹⁰Po and ²¹⁰Pb too. Remember, these substances are invisible, odourless and tasteless.

I am constantly amazed by the fact that although more than half the population hates smoking and finds the smoke a great nuisance, not much is being done to show our annoyance. Most people just put up with this by a quick wave of the hand or hold their breath while walking past the plumes of white smoke. While the smoker has a right to smoke and damage his health, you have a right to demand that he does not damage your health in the process and pollute the environment too. So, next time someone lights up next to you, say something. You are helping him as well as yourself!