The dangers of being overweight or obese are well known: diabetes, cancer and heart disease to name just three. But being underweight – having a body mass index (BMI) lower than 18.5 – is too low for optimal health and can also trigger a number of health problems, according to the NHS. Here’s some of the worst.
DEMENTIA
Being underweight increases the risk of dementia, according to a US review of international studies involving more than 37,000 people. The research, published in the journal Obesity Reviews, found that while being obese increased the risk of dementia by 42 per cent, being underweight was almost as dangerous with a heightened risk of 36 per cent over healthy weight adults.
OSTEOPOROSIS
Although it’s more common in women, being underweight can lead to decreased bone mineral density in men, according to a study of more than 100 Brazilian men. This can lead to weak, brittle bones and joint and mobility problems as you get older.
INFERTILITY
Men with a BMI lower than 20 are as likely to suffer fertility problems as those who are overweight or even obese, according to a study of more than 25,000 couples in Norway published in the Journal Of Human Reproduction.
WEAK IMMUNE SYSTEM
To fight off infections, such as flu, the body must burn extra energy. But being underweight, combined with a reduced calorie intake, may mean you do not have the sufficient energy stores needed to fight off the bugs, according to an article in the Journal Of Nutrition.
ANAEMIA
A lack of dietary iron can lead to anaemia. Iron deficiency severely restricts the amount of oxygen your red blood cells can carry, resulting in exhaustion, heart palpitations, dizziness and fainting. Boost your levels by eating red meat and leafy green vegetables.
DEATH
Having a BMI lower than 18.5 results in ‘significantly increased’ risk of death from causes other than cancer and heart disease, according to a report published in the Journal Of The American Medical Association.
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