by Monica Reinagel, M.S.,L.D./N.
I’ve gotten a lot of questions from listeners about the pros and cons of juicing so today I’ll take a closer look at the claims and give you my take on what juicing can and can’t do for you.
Juicing for Health and Nutrition
Fresh fruit and vegetable juices have a reputation for being super healthy, and it’s true that juices can be a concentrated source of valuable nutrients. As Steph commented in an email, you often hear people say that the nutrients in juice are also easier for your body to absorb than the nutrients in whole fruits and vegetables. And there is some evidence that certain nutrients, especially those in the carotenoid family, seem to be better absorbed from juice.
Carotenoids are found in carrots, of course, but also in tomatoes, spinach, apricots, melons, peppers, and lots of other brightly-colored fruits and vegetables. This class of nutrients seems to play a big role in preventing cancer.
But the nutrients aren’t the only things that are quickly and easily absorbed from juice.
Juice is also a concentrated source of natural sugars. If you consume it without any other food, juice passes relatively quickly through your stomach to your small intestine, where the both the nutrients and the sugar are rapidly absorbed.
Faster Isn’t Always Better
When it comes to sugar, rapid absorption isn’t necessarily a good thing. A big glass of fresh juice can cause a sudden sharp rise in your blood sugar, which in turn provokes a big release of insulin from the pancreas, which then causes a quick drop in blood sugar.
That particular roller coaster is the sort of thing we like to avoid. For one thing, the blood sugar roller coaster isn’t very fun to ride. Your energy levels tend to go up and down with the rise and fall of your blood sugar and you usually end up hungry sooner than you would if you ate foods that are more slowly digested.
For another thing, the blood sugar roller coaster ride is tough on the pancreas. It can even set up a situation where your cells lose their sensitivity to insulin and your pancreas can’t produce enough to get the job done--otherwise known as Type 2 diabetes. I’m not saying that drinking fresh juice will give you diabetes, but the high sugar content is something to be aware of--especially in juices made from carrots, beets, and most fruits.
At the same time, I’m always nagging you to eat more fruits and vegetables and, as Niki points out, fresh juice can be a way to work in more servings than you might otherwise get--or to sneak in some types of nutritious vegetables that you otherwise wouldn’t eat at all. True enough.
As a rule, it takes many servings of fruits and/or vegetables to produce a single serving of juice. So you could theoretically get your entire day’s requirement of vegetables by knocking back a few ounces of juice. But unlike whole fruits and vegetables, juice has no fiber. And one of the ways in which eating more fruits and vegetables improves your health is by increasing your fiber intake; so if you’re leaving all the fiber in the juicer, you’re missing out on that important benefit.
Whole Juice Versus Extracted Juice
And that’s where “whole juicers” come into the picture. Instead of extracting the water, sugar, and most of the nutrients from fruits and vegetables and leaving all the fiber and pulp behind, whole juicers are more like blenders that liquefy entire fruits and vegetables. Whole juice will still cause a more rapid rise in blood sugar than eating the same amount of unpulverized produce, but not as rapid a rise as drinking extracted juice.
With whole juicers, you get all the benefits of the juice, plus all the fiber and any nutrients that would otherwise remain in the pulp. Many people see this as the best of both worlds--a way to pump up their diets with some extra plant nutrition and still get the benefit of the fiber.
Here’s what the whole juicer people don’t tell you, though: Pulverized fruits and vegetables are too thick and pulpy to drink. And diluting them with water makes them flavorless. You need to add some sort of extracted juice (either fresh or bottled) to make them drinkable.
With Juice, Time Is Your Enemy
Whichever kind of juicer you choose (I have to admit, I have one of each), the juice will only be as nutritious as the fruits and vegetables you start with, so you want to be juicing fresh, seasonal produce. It’s also important to drink your concoctions as soon after they are made as possible. The antioxidants and other phytonutrients start to break down almost immediately once they are exposed to light and air.
For example, no matter how healthy the ingredients sound, those expensive bottles of juice from the health food store will have lost a lot of their nutrition by the time you drink them. If it’s peak nutritional value you’re after, you’re better off stopping at a juice bar or making your own.
Juicers--both the extraction kind and the whole food blender-type—will set you back a few hundred dollars; and making either type of juice can be a messy and time-consuming process. Rachelle wonders whether making a larger batch of juice and freezing some of it in small bottles would be a good way to save time and preserve the nutrient content of the fresh juice.
I think Rachelle is onto something. As you might remember from my show on how cooking affects nutrients, freezing is pretty easy on nutrients. Some of the nutrients will still be lost, but freezing fresh juice and drinking it within a few days is probably the best way to preserve most of the nutrients but cut down on the mess and hassle of making juice every day.
Juice as Part of a Healthy Diet
Here are some final thoughts on incorporating fresh juice into your diet:
If you’re drinking juice as a meal or snack, whole juice will probably help keep your blood sugar levels steadier and keep you from being hungry an hour later.
Consuming nothing but juice—no matter how many nutrients it contains—is not a balanced diet because it provides no fat and no protein. If you’re otherwise healthy, it’s fine to consume nothing but fruit and vegetable juice for a day, but any sort of extended fasting--including juice fasting--should only be done with the guidance of a doctor or nutritionist.
Fresh juice can add a lot of high-quality nutrition to your diet. But I still think it’s ideal to get at least half your fruits and vegetables in a form that you have to chew. You’ll find research references as well as links to more information on juicing and various types of juicers in the show notes. And for a look at how canned vegetable juice stacks up to fresh juice, head over to this Quick Tip.
Lastly, for a Quick Tip on getting your fruits and vegetables clean of soil, bacteria, and pesticides in a cheap and effective way, head on over here.
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Have a great day and eat something good for me!
Research comparing nutrient absorption from vegetables versus vegetable juice. (from Cancer Epidemiology, Biomarkers, and Prevention)
A skeptical look at benefits of juicing by Steve Barrett, M.D. (from Quackwatch.org)
Juicer Comparison Chart