Mostly no. Juicing does not destroy the vitamins and minerals in fruit and vegetables. Nothing is cooked, and a spinning blade does not break them down. What you lose is fibre, which stays behind in the pulp, and a small amount of vitamin C that fades once the juice meets air. Fresh juice keeps most of its nutrition and gives up its roughage.
I make a green juice most mornings, and I have read enough of the alarming headlines to want the real version. This is it, without the drama.
What the machine actually does
A juicer breaks the plant cells open and presses the liquid out through a mesh or a cloth. Most vitamins and minerals dissolve in water, so they travel out with that liquid and land in your glass. The insoluble fibre, the skins and strings and cell walls, is held back as pulp. That is the whole trick. The machine separates juice from fibre. It does not damage the nutrients sitting inside the juice.
Heat is what destroys vitamins, not pressure. Boiling a pan of vegetables for ten minutes leaches and degrades water-soluble vitamins far more than any juicer will. If you want the short answer to why raw juice has a reputation, that is it.
Which nutrients survive, and which do not
Minerals hold up best. Potassium, magnesium and calcium are stable and they pass into the juice. The fat-soluble vitamins, A, E and K, come through as well, and most B vitamins survive the trip.
Vitamin C is the fragile one. It is water-soluble and it reacts with oxygen, heat and light. A review in Advances in Nutrition (Clemens and colleagues, 2015) put it neatly: turning whole fruit into juice keeps its nutritional value, with the exception of fibre and vitamin C. The rest tends to survive when the juice is made and stored properly.
Fibre is the clear loss, and I have covered that on its own. If that is your main worry, read my piece on does juicing remove fibre.
The vitamin C question, properly
Once you cut a piece of fruit open, the vitamin C starts to drop. Oxygen in the air reacts with it, and the reaction runs fastest in the first few hours after juicing. Heat speeds it up and light speeds it up. Leaving a jug on the worktop all afternoon is about the worst thing you can do to it.
Studies on citrus juice storage show vitamin C falling fastest at the start, then sliding further as the days pass, with warmer storage losing more than cold (Burdurlu and colleagues, 2006; Nakilcioglu-Tas and colleagues, 2020). That is a reason to drink fresh juice fresh, keep it cold and keep the lid on, rather than a reason to avoid it.
If vitamin C is your goal, some produce is unusually strong on it. Amla is the standout, and red pepper beats an orange per gram. Both have recipes here: amla, apple and orange juice and red pepper, cucumber and lemon juice.
Is bottled juice worse than fresh?
On this one point, usually yes. Bottled juice is pasteurised, meaning it is heated to kill microbes and hold it stable on a shelf. That heat reduces vitamin C and other heat-sensitive nutrients, and a long shelf life lets the rest of the vitamin C drift down. Juice from your own machine keeps more of it. I compared the two properly in is bottled juice as good as fresh.
How to keep the most nutrition in the glass
Drink it the same day. If you cannot, seal it in the fridge and fill the bottle right to the top so there is little air left to react with, and keep it out of the light. Those small habits recover a lot of the vitamin C that would otherwise slip away.
Then remember the trade you are making. You are swapping fibre for speed and for a way to drink vegetables you would not sit and chew through. That is a fair trade for one small glass a day. It stops being fair when the juice replaces eating fruit and vegetables whole.
FAQ
Does blending destroy nutrients?
No. A blender does not heat anything, so the nutrients stay, and because you drink the whole puree you keep the fibre too. A blender holds on to more of the original fruit than a juicer does. The reason people still juice is texture and taste, not nutrition.
Does your body absorb nutrients better from juice than whole fruit?
No, and this is one of the most common juicing claims going. Mayo Clinic is clear that the body does not absorb nutrients better from juice. Because juicing strips out the fibre, the sugar in juice reaches your blood faster than the sugar in the whole fruit. Whole is generally the better deal.
So is juicing bad for you?
No. The NHS advises keeping fruit juice and smoothies to one small glass, 150ml, a day and having it with a meal, because it is high in sugar and sipping it through the day can damage teeth. Inside that limit, fresh juice is a good source of vitamins and minerals. It counts as one of your 5 a day, but only ever one, however much you drink. I went through that in does juice count as 5 a day.
More honest answers on juice and health: cold pressed juice benefits, juicing vs smoothies, and is juicing healthy. For recipes, browse the immunity juices and the weight loss juices.