Complementary medicine is awash with charlatans and shysters peddling more miraculous cures than there are diseases to be cured. The same can be said of orthodox medicine, which makes distinguishing truth from hype so very, very difficult. So when it comes to the astonishing health claims made for the practice of juicing fruits and vegetables, I take the same approach as I would to any purported wonder-cure, which is to wonder what the evidence is.
Peruse any website extolling the virtues of juicing and you will discover that this practice variously detoxifies the body, builds blood cells, energises, cleanses the skin and kidneys, performs ‘cellular cleansing’, helps you lose excessive weight, is ‘highly eliminative’, improves clarity of mind and even leaves you with a natural high. Who needs nirvana, or sex, when you’ve got all that going on simultaneously.
Juicing involves taking a whole fruit, or vegetable, and stripping it of the fibre content so that only the fluid is retained. Drinking juices is often central to a fast, or detox regime. Stripping a whole food of its fibre content is what those much maligned, junk food manufacturers do, creating refined carbohydrates which have come to be associated with a range of diseases, from constipation and bowel cancer to type 2 diabetes and heart disease. Yet when juicing advocates do they same thing they say they say that by eliminating the fibre you are giving the body a rest. Ha ha – that’s cunning spin, if nothing else!
So, to the facts. First, let’s consider fruit juices. Drinking fruit juices gives you a great deal of unbound fructose (fruit sugar) which, like ordinary table sugar, is a significant contributor to dental erosion. Also, once extracted, fructose is much sweeter than either glucose or sucrose. Concentrated fructose has been found to increase blood fat levels and is linked to insulin resistance (one step away from diabetes) and high blood pressure. Fructose is more lipogenic than glucose, which means that it is more readily converted into fat.
So what about vegetable juices? These have less sugar, and one of the reasons they are heavily promoted is their rich carotenoid content. Carotenoids are antioxidant plant chemicals (also known as phytonutrients, or phytochemicals) and this group include beta carotene, as found in carrots. But peeling and juicing have been shown to result in ‘substantial losses of carotenoids, often surpassing those of heat treatment.’ Other plant chemicals are also reduced. A study of the loss of anthocyanins in blueberries found that approximately 20% of these powerful antioxidants were left behind in the pulp after juicing.
Most of the health claims relating to juicing, that trip too readily off the tongue, are based on their high nutrient content, but just a nanosecond of thought will tell you that these nutrients are already present in the whole food – you don’t get more by juicing. Juices contain nothing extra, but a lot less. I contacted a couple of companies whose websites promote juicing, and sell juicing machines, to ask them for evidence of their eye-popping health claims. Neither got back to me.
Juices can be delicious and you can do a lot worse than indulge yourself occasionally at a juice bar. Just don’t expect an orgasmic or life-changing experience.
References
Bray, G.A. (2007) How bad is fructose? American Journal of Clinical Nutrition, 86(4):895-896.
Elliot, S.S., Keim, N.L, Stern, J.S. Et al (2002) Fructose, weight gain, and the insulin resistance syndrome. American Journal of Clinical Nutrition, 76(5):911-922.Committee on Nutrition (2001) The use and misuse of fruit juice in pediatrics. Pediatrics, 107:1210-1213.
Dutta, D., Chaudhuri, U.R. & Chakraborty, R. (2005) Review: Structure, health benefits, antioxidant property and processing and storage of carotenoids. African Journal of Biotechnology, 4(13):1510-1520.
Kalt, W. (2004) Effects of production and processing factors on major fruit and vegetable antioxidants. Journal of Food Science, 70(1).