I have been saying for years that the habit of juicing is not the healthy factor that people think. A recent study has finally shed some more light on the reasons why this practice is not healthy. Concentrated juicing of veggies can rapidly raise the level of vitamin K in the body. Vitamin K is the coagulating vitamin and if someone is taking a blood thinner for medical reasons the vitamin, to excess, can prevent the blood thinner from working.
Diabetes: Drinking juices from excessive amounts of fruit raises the blood sugar and can contribute to developing diabetes or making an existing problem worse.
Thyroid: Excessive amounts of certain veggies such as kale, bok coy, cauliflower, collards and spinach are rich in compounds that can depress thyroid hormone production leading to an under active thyroid.
Excess calories: Those watching their weight often think that a juice drink is a great way to cut calories. Not so. Many juice concentrates are very high in calories. The average juice smoothie can add over 600 calories to your daily intake!
Other potential problems connected with juicing can be a lack of fiber since most juicers extract the fluid and leave the solid fiber behind. Lastly there is the oxidation factor. The juicing process forces oxygen into the juice. If the juice is not consumed very quickly the oxygen breaks down the nutrients in the juice and oxidizes the fruit sugars.
It has always been and will always be that the best way to consume veggies and fruits are in their natural state. That way you get all the health factors present the way nature intended it.