Have you ever heard the term ‘juicing’? When someone is juicing, their diet is mainly fruit and vegetable juice for 3-10 days. Do you know someone who is juicing? Or have you ever considered juicing? Well, the answers from me are all yes! But, I did not do it because I hate the taste of the juice that I made without any sugar addition, especially the taste of vegetable juice!
Recently I was attracted by a post on the wall of the building in which I am doing my research. Leo Vanhanen, who is working in the Department of Wine, Food and Molecular Biosciences of Lincoln University and mainly focus on food science, has found that over 80% of the calcium of the original fruit and vegetables binds into the fiber fraction, which is normally discarded while making juice with juicer. We all know how important calcium is to our body.
There is another research output posted next to the previous one I mentioned. Spinach is a common component of the juicing recipe, but the green juice with it, no matter in low or high level, contains significant amounts of soluble oxalate. Although the pulp fraction contains both soluble and insoluble oxalate in a high level, the study shows that removing the pulp doesn’t decrease the soluble oxalate level in the juice.
Why is oxalate was specifically studied? Because dietary intake of soluble oxalate directly increases the concentration of urinary oxalate, which increase the risk of kidney stone development in susceptible people. Dietary restriction of oxalate has alread been used to recude the risk of recurrence of calcium oxalate kidney stone.
I was so glad that I didn’t follow the trend becoming of those are “juicing”!
As advertised, juice is from natural plants, so it is healthier than other drinks. Juice has less carbohydrate than bread, rice, noodles, and other drinks, so it is able to help a woman losing bodyweight. But, is your vegetative juice actually healthy as you expected?
First, juice helps people who don’t like to eat vegetables or fruits to more easily consume vitamins, minerals and increase their water intake.
Second, the vegetables and fruits are not cooked or heated and so contain more nutrient element, for example, vitamin C, which is easily broken under higher temperature. But it does not decrease the potentially toxic anti-nutrients, such as oxalate, as well as increasing the concentration of these toxins. Some nutrient elements are not easily absorbted by water solution, for example, carotene, which is mainly found in carrot and tomato and is a precursor to vitamin A. These should be consumed with unsaturated fatty acids (mostly are oil from plants).
Third, if you drink juice without pulp, most fiber is discarded, which actually makes you feel hungry again in a shorter time. Scientific evidence shows that if a person drinks juice from an orange, he/she feels hungry quicker than when he/she eats that orange. Some people may tell you that juice still has soluble fiber, but soluble and unsoluble fiber acts differently. Soluble fiber absorbs fluid and makes the bowel contents softer and able to move more easily. It also helps lower blood cholesterol and improve blood glucose control. Insoluble fibre acts as a ‘bulking agent’ which, with soluble fibre, helps to keep us regular. Contrarily, if you make juice with a blender, and take away the fiber, you can cause gas and a diarrhea problem. This is not, as commonly stated, a symptom of flushing toxins from body!
Fourth, the process of making juice causes oxidization of many antioxidant compound from fruit and vegetables. If left unpeeled, apples becomes brown, bananas becomes dark. This is oxidation in action and the same thing happens when you juice. So if you want nutrients from your fruit as much as it has, just eat them directly.
Why, if there are these issues, are juice diets becoming popular? As with many other problems, you will be shocked by the promises of advertising, and even lies for making you believe its efficiency.
Should you drink? Think about your purpose! If you are trying to lose weight by juicing for a period, I suggest not, because your hormones won’t know that you want to lose weight, unless you are going to use a long time like one year to adjust your hormone response.
The author Chen Zhang is an postgraduate student in the Postgraduate Certificate in Applied Science taught at Lincoln University. She wrote this article as part of her assessment for ECOL 608 Research Methods in Ecology.