text: She recently turned 51 but Elle Macpherson's good looks, toned body and age-defying skin would have you believe otherwise. So what's her secret? The model has revealed that she carries around a pH balance urine tester kit wherever she goes to check the state of her body. In an interview with the Evening Standard, the  model admitted that the most surprising thing in her handbag is the tester kit, which she uses to check her state of alkaline. Scroll down for video . Elle Macpherson, who turned 51 last month, has revealed that she carries around a pH balance urine tester kit wherever she goes to check the state of her body . Elle said: '(The most surprising thing in my handbag is) a pH balance urine tester kit to check that I'm in an alkaline state. I believe that most ailments come from having an acidic body.' The body's pH value tells you how acidic or alkaline your body is, and many nutritionists say that having an alkaline body helps defend against sickness and disease. An alkaline body can be achieved by eating the right foods (lots of leafy greens) and exercising. Having been labeled 'The Body' since the 1980s, Elle has had to make sure her physique is in peak condition at all times, and the Britain's Next Top Model host puts her figure down to 'variation' and 'consistency'. The body's pH value tells you how acidic or alkaline your body is, and many nutritionists say that having an alkaline body helps defend against sickness and disease. Elle is well-known for her healthy diet and even released her own superfood product, The Super Elixir . She said: 'Variation is key. I work out 45 minutes a day, six days a week, combining hiking, water skiing, swimming and running on a beach. '(My idea of a healthy diet is) consistency and eating three healthy meals a day. Having said that, red meat, wheat and dairy don't work for me.' Like fellow models Miranda Kerr and Rosie Huntington-Whiteley, Elle swears by the power of all things green and she is so convinced by their potency, that she's unveiled her very own brand. Last year, Elle introduced The Super Elixir by WelleCo, a range of alkalising food supplements, which she describes as her drug. She hasn't aged a day! Having been labeled 'The Body' since the 1980s, Elle, pictured, left, in 1995 and, right, in 2012,  has had to make sure her physique is in peak condition at all times . The product was formulated over many years especially for Elle by Dr Simone Laubscher PhD, a Harley Street nutritional doctor specialising in disease prevention. The powder, which can be sprinkled over salads or mixed into juices and smoothies, claims to support healthy nutrition and ensure your body is working to its optimum function. Speaking to FEMAIL at the time about the inspiration behind her new range, Elle said: 'I'm on the run a lot and if I'm not nourished, I don't feel good. 'For years, I was taking vitamins and powders. I tried alternative medicine, acupuncture, reflexology. 'I'm a pescatarian, I don't drink, do drugs or smoke so what else can I do? I wasn't unaware of wellness but something wasn't working for me and I told my doctor "I don't feel great". 'She told me my body was acidic, it was down to stress, travel and lack of sleep.' Elle has co-created The Super Elixir Nourishing Protein, which is made from locally sourced organic sprouted brown rice, pea protein chocolate and Peruvian cacao and a product that the supermodel credits for helping her get ready for beach holidays . So successful was the launch of the elixir that the duo have added another product to the range: The Super Elixir Nourishing Protein. Made from locally sourced organic sprouted brown rice, pea protein chocolate and Peruvian cacao, the £45 product is a plant based complete protein, containing all nine essential amino acids like those found in red meat, eggs, chicken and fish. 'Not only do I love the delicious chocolate taste but I enjoy sport and need a good source of clean protein for muscle repair, energy and of course getting ready for that beach holiday,' said Elle of the latest health product.
target: Elle cites the item as the most surprising thing in her handbag .
  The body's pH value tells you how acidic or alkaline your body is .
  Many nutritionists say having an alkaline body helps defend against sickness .
  Elle has unveiled a new health product: The Super Elixir Nourishing Protein .