What your hair says about you

New tests can reveal how much alcohol a person has drunk months earlier, just by analysing a single strand of hair. In fact, your hair stores a record of pretty much everything you do. One centimetre of hair growth represents a month, so a 24-centimetre strand can represent two years of your life. From this alone, scientists can tell what you eat, what medicine you took a year ago and whether you used cocaine at a party three months ago. Hair analysis can even predict your fertility levels and mood, reveals Anastasia Stephens...

THE TYPE OF FOOD YOU EAT

"A strand of hair might tell you if someone switched from a meat-eating diet to an animal-free diet," says Patrick Holford, founder of the Institute of Optimum Nutrition. Hair follicles are bathed in the body's fluids and absorb the substances it contains, so labs can analyse hair for all known minerals. "Minerals reflect your diet," continues Holford. "A meat-eater will have more iron and zinc than someone who eats no meat; if levels dropped five centimetres along a hair shaft, it might be a sign they switched to a vegetarian diet five months ago."

THE FERTILITY MINERAL

If you are having trouble conceiving, it might be worth getting your hair analysed for minerals. "Zinc is essential for male and female fertility; we need 15mg of zinc a day, but most people only get half that in their diet. Low levels are associated with malformed and poorquality sperm," says Holford. "If low levels are found in your hair, it might provide a clue to fertility problems."

PRE-DIABETIC SYNDROME

If your hair becomes dry and coarse, you feel tired and have put on weight around the middle, it could be a sign of syndrome X, a pre-diabetic state associated with poor blood-sugar control. The chances are the change in hair texture is linked with cravings for sweet foods or carbohydrates followed by sudden energy dips. Dry, coarse hair is also linked to hypothyroidism, where low levels of the hormone thyroxine cause your body's metabolism to slow down.

TESTOSTERONE SENSITIVITY

If your hair becomes greasy fast, it may be a sign you have testosterone sensitivity. This condition, associated with the over-production of the hormone sebum, is common in teenagers. It also occurs in women with polycystic ovaries, a common-cause of infertility. These women may develop male-pattern hair growth, such as hairs growing around the chin.

HORMONE IMBALANCES

If your hair starts coming out in clumps, your hormones may be out of balance. High levels of stress hormones, the menopause and abnormal fluctuations in the metabolic hormone, thyroxine, can all cause hair to fall out. This may be rectified by balancing your hormones or relaxing, so that your body can heal naturally.

YOUR STATE OF MIND

Mood and personality disorders have been linked to exposure to toxic and heavy metals. Patrick Holford says he has predicted mood disorders through hair analysis alone.

"In one hair, I found high levels of lead and predicted its owner would be prone to aggressive and impulsive behaviour. Two other hairs I tested showed excessive levels of copper, which can cause anxiety and depression. The hair that was high in lead belonged to a schoolboy who had been given psychotherapy and ECT for severe behavioural problems. The hairs high in copper belonged to a couple living in a house with new copper-lined pipes. The wife was on tranquillisers, suffering from anxiety."

If you suffer depression for no apparent cause, a hair analysis followed by nutritional therapy to flush out excess metals may be a good idea.

IF YOU HAVE TAKEN DRUGS RECENTLY

"We can tell if a person has taken cocaine, ecstasy, speed or heroin as long as six months ago, up to six centimetres along a hair-shaft," says Ric Treble, forensic scientist at LGC, which conducts biochemical hair analysis. "Traces of drugs are detectable further down a hair, but estimating the time of use becomes less accurate. We can also tell if a person has taken drugs for a short period of time, or if they are habitual users. But how much a person has taken is harder to detect - dark hair takes up more drug-residue than blonde hair."

IF YOU ARE ANAEMIC

Hair analysis can reveal low iron levels, a classic cause of anaemia and fatigue, especially in women with heavy periods. Excessive hair loss may be a sign of iron-deficiency anaemia, caused by a low blood cell count. Anaemia symptoms include dizziness, fatigue and poor concentration.