Thin people can lack oestrogen, the 'female' hormone that is important for the well being of women and men Wallis Simpson, the Duchess of Windsor, was at best only half-right when she said: ‘You can never be too rich or too thin.’ In fact, being too thin can be seriously unhealthy. Scientists revealed last week they’d discovered a ‘lean gene’ that puts thin men in danger of developing diabetes. This is just the latest piece in a growing body of evidence that shows how being skinny can expose people to a range of serious problems. These include a raised risk of miscarriage, lung disease, male infertility and even death in car accidents. So what counts as underweight? Officially, it means a body mass index, or BMI, below 18.5. (Your BMI is your weight in kilos divided by your height in metres squared.) Last week’s study showed that a gene called IRS1, which keeps some people skinny, is linked to a raised risk of Type 2 diabetes and cardiovascular disease. Dr Ruth Loos, a Cambridge University scientist involved in the study, says that though the gene makes people look slim, men who have it may deposit fat internally in dangerous places around the liver and heart. This ‘lean gene’ is only part of the picture. The research is still in its infancy, but scientists have calculated that being underweight is associated with 34,000 deaths a year in the U.S. This compares with 112,000 deaths annually from serious obesity. While being clinically overweight is the main size-related danger, being skinny brings its own hazards. Sian Porter, a consultant dietitian and spokeswoman for the British Dietetic Association, says that underweight people are often unaware that any of their health problems may be due to their size. ‘All the headlines are about the dangers of obesity. And thin people are always being told: “Aren’t you lucky,” ’ she says. One of the causes of problems may be hormonal. Thin people can lack oestrogen, the ‘female’ hormone that is important for the well being of women and men. Lack of body fat is also linked to the loss of other chemicals essential for physical and mental health. Here are an unlucky seven risks, proven by research, of being fashionably thin: BROKEN BONES Women who have always been thin are at a raised risk of hip fractures in middle age, according to a study of 3,683 women in the Archives of Internal Medicine. Hip fractures are a leading cause of injury among women in middle age and death among older people. The thinner a woman is, the lower her bone density. Fat fuels oestrogen production, which the body needs for healthy bones. Too little oestrogen can make bones porous and brittle. Also, bones need to carry weight to remain strong. This makes weight-bearing exercises, such as running, jumping and lifting, important for thin people. (In obese people, the bone benefits of being heavy are negated by wear and tear on joints such as the knee and ankle). One strategy for preventing bone breakage in thin middle-aged women is to put on a few pounds. The study in the Archives Of Internal Medicine found that a weight gain of at least 10lb between the ages of 40 and 60 appeared to increase bone density and reduce the fracture risk. Other studies have found that a weight gain from underweight to normal after the age of 25 is associated with a reduced risk of a broken hip. Dietitian Sian Porter says it is relatively straightforward for most people who are underweight to put on pounds. ‘It is not difficult for people with low BMIs to gain weight. Having snacks between meals, drinking a glass of milk before bedtime and adding cereal or toast to their breakfast — it doesn’t take much, particularly as slim people often don’t eat much. In fact, they often eat less than they think.’ ARTHRITIS AND heart disease Underweight people who have arthritis are three times more likely to die from heart disease in middle age than people of normal weight. Experts at the Mayo Clinic in the U.S. discovered the link after following hundreds of people’s health records over 42 years. They believe thin people are more prone to the effects of inflammation elsewhere in the body triggered by severe arthritis, and this can have a deadly effect on the heart. Research shows that chronic inflammation plays an important role in atherosclerosis, the process in which fatty deposits build up in the inner lining of arteries. MISCARRIAGE Very thin women are at risk of severe nausea during pregnancy Women who have a low BMI before they become pregnant are 72 per cent more likely to suffer a miscarriage in the first three months of pregnancy, a team from the London School of Hygiene & Tropical Medicine has reported. The study of 603 women who had suffered early miscarriage did not find a precise reason for the link. But according to pregnancy expert Heidi Murkoff, the oestrogen produced by fat cells is closely tied to fertility and healthy pregnancies. Very thin women are also at risk of severe nausea during pregnancy, according to a study of 943,000 Swedish women. In a small percentage of women, morning sickness spirals into a condition called hyperemesis gravidarum. This causes unrelenting vomiting that puts them at risk of malnutrition and dehydration. The dangers for mother and foetus mean that the woman may need to be hospitalised and put on a drip. The study found that women who are underweight before pregnancy are 43 per cent more likely to end up in hospital with the condition. Sian Porter often sees underweight women because they are having trouble conceiving. ‘I think it’s nature protecting itself,’ she says. ‘It stops women menstruating when their food intake is limited and potentially lacking in key nutrients, because it sets off alarms about famine.’ DEPRESSION Thinner men carry a significantly higher suicide risk Thinner men carry a significantly higher suicide risk. The first investigation into this link was made in 1966 and has been confirmed by subsequent studies. Last year, a decades-long follow-up of more than one million Swedish men found that suicide risk drops with rising weight. Skinny men are 12 per cent more likely to commit suicide than those of normal weight, while overweight men are 12 per cent less likely to do so, says the report in the American Journal Of Epidemiology. The study’s leader, Dr Finn Rasmussen of the Karolinska Institute in Stockholm, says that constantly feeling puny might have a corrosively demoralising effect. It is also possible that skinny men’s bodies produce insufficient levels of the feel-good brain chemical serotonin. When thin men attempt suicide, they are more successful at it than overweight ones, the statistics show. Experts say this may be because, sadly, they are better equipped for it — they are more likely than overweight men to choose suicide methods that require more physical ability and are more lethal, such as hanging or jumping to their deaths. Another possibility is that drug overdoses are less likely to be fatal for heavier men, since larger bodies require larger doses to be deadly. LUNG DISEASE Slender, older women are more susceptible to a range of chronic lung problems such as bronchitis, pneumonia and asthma, according to a long series of studies over the past 20 years. Research in the journal Gender Medicine suggests that this may be due to a combination of factors. The woman’s relative lack of oestrogen may cause problems with her immune system. On top of that, she may lack adipokines — cells secreted by fatty tissue that do a vital job in running the immune system. Thin women could also have problems with growth-factor hormones crucial to the constant maintenance of healthy lung tissue. MALE INFERTILITY Being too thin can affect a man’s fertility, according to research by Aberdeen University. The problem is a lack of healthy sperm, according to Dr Ghiyath Shayeb, who led the study of more than 5,000 men. The researchers looked at the results of tests on 5,316 men who attended a fertility centre over difficulties conceiving. ‘There does seem to be a real connection between weight and sperm,’ says Dr Shayeb. The reason for this may be explained by a Danish study that found sperm counts are more than a third lower in underweight men and so was the concentration of their sperm — another important measure of fertility. Experts speculate that a lack of oestrogen — it is produced by men’s fat stores — may be part of the problem because a balance of testosterone and oestrogen is crucial for sperm production. CAR CRASHES Skinny men are more likely to die in car accidents than normal-sized or overweight drivers. The phenomenon was identified in the American Journal Of Public Health by a Wisconsin Medical College study of 22,000 drivers. The investigators found that it is best to be an overweight woman in a road smash — they have the best survival rate of all, most probably thanks to their generously proportioned curves (the ‘built-in airbag effect’). Slim women did not have any greater death risk than normal-sized women. By contrast, thin males are most likely to be killed by a collision — their extreme lack of padding makes them more fragile. Source
