What happens to your body when juicing?
Introduction
Juicing has become an increasingly popular way to get more fruits and vegetables into your diet. By extracting the juice from fresh produce, you are able to consume a large amount of nutrients, vitamins, and minerals in their raw, natural form. Many people choose to juice as part of a detox or cleanse, while others do it to boost their overall health and energy levels. But what really happens inside your body when you drink these concentrated juices? Here, we’ll take a closer look at the potential benefits and drawbacks of juicing.
Increased Nutrient Absorption
One of the main proposed benefits of juicing is increased absorption of nutrients. When you eat whole fruits and vegetables, your body has to break down the fibers and cell walls during digestion before it can access all the goodness inside. This requires a lot of mechanical and chemical action, with some nutrients inevitably lost or wasted in the process.
Juicing eliminates the fiber content, rupturing the plant cells and making the nutrients from inside much more bioavailable. So in theory, you can absorb more vitamins, minerals, and phytonutrients from the juice than you would eating the whole produce.
Some studies have found juicing leads to higher blood levels of carotenoids, polyphenols, and ascorbic acid after consumption.[1] However, more research is still needed to determine if this increased bioavailability translates into better health outcomes over time.
Nutrient Loss
While juicing makes some nutrients more absorbable, the lack of fiber can also lead to losses of other important nutrients and phytochemicals.
For example, up to 90% of the polyphenols found in fruits and veggies may remain in the fiber pulp when juicing.[2] Many of these polyphenol compounds provide protective health benefits, acting as antioxidants and anti-inflammatories.
Juicing also reduces levels of beneficial probiotic bacteria that live in plant cell walls. We lose the fiber required to feed these bacteria in our gut microbiome. Some studies show lower microbial diversity and increased markers of inflammation after following a juice-based diet.[3]
Finally, the blender blades oxidize and destroy heat-sensitive nutrients during juicing. Significant losses of vitamin C and carotenoids have been reported from pre-packaged juices.[4]
Overall, it’s a tradeoff between greater absorption of some nutrients and potential losses of others when you remove the fiber.
Blood Sugar Spikes
Fruit and vegetable juices are naturally high in simple sugars like glucose, fructose, and sucrose. Without the fiber content of whole produce, these sugars can be quickly absorbed into the bloodstream.
This can lead to rapid spikes in blood sugar and insulin levels after drinking juice, especially those made purely from fruits. One study found that juice consumption led to 83% higher blood sugar levels compared to eating the whole fruit.[5]
Over time, frequent blood sugar spikes from juicing may increase your risk of insulin resistance, metabolic diseases, and type 2 diabetes.[6] This is especially concerning for people with prediabetes or other metabolic conditions.
To help mitigate this effect, you can focus on juicing non-starchy, low-glycemic vegetables and adding healthy fats and protein to your juices. Lentils, avocados, nuts, seeds, and nut butters are good options.
Decreased Satiety and Increased Hunger
Drinking concentrated juice nutrients without the fiber content found in whole fruits and veggies may disrupt normal appetite signals in your body.
Studies show juice results in less satiety, fullness, and prolonged suppression of hunger hormones compared to eating the whole produce.[7] Your brain doesn’t register the juice calories in the same way and may not compensate by eating less at your next meal.
This combined effect of spiking blood sugar then experiencing hunger soon after may lead to overconsumption and unintended weight gain over time.
Dental Erosion
Frequent juicing, especially of acidic fruits, could also damage tooth enamel over time.
One study found that squeezed orange juice starts eroding enamel after just 5 days of exposure.[8] Similar effects have been seen from apple, grapefruit, and other citrus juices.
This can lead to increased dental sensitivity and greater risk of cavities down the line. If you juice regularly, be sure to rinse your mouth with plain water afterward and avoid brushing for at least 30 minutes to protect your enamel.
Potential Pesticide Exposure
Since juicing concentrates produce into a small volume of liquid, it can also concentrate any pesticides or toxins present on the surface of the plants.
Unless you are using certified organic produce, there is a risk of increased chemical exposure from your juice. This is especially true for fruits and vegetables found with the highest pesticide residues, like strawberries, spinach, apples, peaches, and peppers.[9]
Washing produce first helps reduce residues, but cannot eliminate them entirely. Peeling fruits and veggies is another option if you’re concerned about this issue.
Nutrient Deficiencies
Using juice as a meal replacement can lead to restrictive eating patterns and nutrient deficiencies over the long term.
Even if you juice a variety of produce, it is difficult to meet all your nutritional needs from juices alone. You may develop deficiencies in important minerals like calcium, zinc, iron, and magnesium as well as protein and healthy fats.
One case study found heart rhythm disturbances, anemia, and osteoporosis in a woman who had subsisted on juice for over 5 years.[10] Be sure to incorporate other whole, nutrient-dense foods in your diet and use juicing to supplement, not replace regular meals.
Detox and Cleanses
Many people turn to juicing as part of a detox or cleanse diet. Proponents claim that flooding your body with concentrated nutrients gives your digestion and liver a break, allowing them to more efficiently eliminate toxins.
However, there is little scientific evidence that detox diets actually remove toxins from the body.[11] Your liver and kidneys are already highly effective at metabolic waste excretion through normal functioning.
That said, drinking antioxidant-rich green vegetable juices can still provide a healthy boost and motivation to cut back on processed foods, alcohol, and other toxic exposures. Just be wary of extreme low-calorie juice cleanses, which can deprive your body of essential nutrients.
Weight Loss
Replacing high-calorie, sugary drinks and meals with vegetable and green juices can help you cut calories and manage weight. But juices alone provide an inconsistent strategy for long-term weight management.
Any weight lost is likely to be partially from muscle mass breakdown in addition to fat due to the low protein intake.[12] You also need fiber for satiety, balanced energy, and feeding the beneficial gut microbiome.
Limiting juice-only fasts to 1-3 days can provide a reset. But incorporate whole produce and high-protein foods if using juicing as a longer-term diet strategy. This ensures weight loss results from fat reduction rather than muscle or water.
Improved Hydration
Drinking juice is an easy way to increase fluid intake and improve hydration, especially if you struggle to drink plain water.
Juice provides hydration from the liquid content as well as the water bound within the produce. This can help normal bodily functions like circulation, digestion, cognitive performance, and temperature regulation.[13]
However, your kidneys still need adequate water as well to flush out toxins and concentrate electrolytes properly. So continue drinking water in addition to juicing for hydration.
Potential Benefits for Cancer Patients
Juicing and nutritional supplements are sometimes recommended to cancer patients dealing with appetite loss, nausea, and cachexia during treatment.
The concentrated nutrition and phytochemicals from produce may help support immune function and strength when regular foods become unpalatable or difficult to digest and absorb.[14]
Always consult your oncology team before making major dietary changes like juicing. Monitor for unintended weight changes which could impact treatment efficacy and outcomes.
Juicing vs. Blending
Both juicing and blending make it easier to consume more fruits and veggies. But is one option healthier?
Juicing extracts the liquid nutrients while removing the fiber in pulp. This provides greater concentration of vitamins and phytochemicals but eliminates benefits from fiber and plant cells.
Blending keeps the entire fruit or vegetable intact, just broken down into an easy-to-drink smoothie. This retains all the nutrients and fiber content.
For most people, blending results in better retention of nutrients, probiotics, and satiety benefits. But those with digestive issues like IBS may absorb more nutrients from juicing.
In either case, incorporate a diversity of whole fruits and vegetables in your diet. Juicing or blending makes it easier to reach daily produce recommendations.
Potential Downsides and Considerations
While juicing does have some benefits, there are also some potential downsides to consider:
– Loss of fiber – Juicing removes insoluble and soluble fiber from fruits and vegetables which provide many health benefits.
– Nutrient deficiencies – Juice diets may be low in protein, fatty acids, and minerals like iron, zinc, and calcium.
– Blood sugar spikes – The simple sugars in juice can elevate blood glucose rapidly without fiber to slow absorption.
– Dental erosion – Frequent exposure to acidic juices may damage tooth enamel over time.
– Foodborne illness – Unpasteurized juices could expose you to pathogens like E. coli or Salmonella if produce is not washed sufficiently.
– Pesticide exposure – Juicing concentrates any chemicals present in or on the surface of conventionally grown produce.
To mitigate these risks, alternate juices with whole produce and foods high in protein, fat, and fiber. Wash produce thoroughly and peel when possible. Drink water to rinse acids from your teeth after juicing.
Who Should Be Cautious With Juicing?
While fresh juices can be a healthy choice for many people, some individuals should exercise more caution:
– Those with diabetes or blood sugar dysregulation issues – The sugars in juice can spike blood glucose.
– People taking certain medications – High vitamin K levels in green juices may interact with blood thinners. High oxalate juices could be problematic for those prone to kidney stones. Discuss juicing with your doctor.
– Children – Juice doesn’t provide complete nutrition for growing kids. Whole fruits and veggies are better.
– Individuals who are underweight or malnourished – Replacing meals with only juice can exacerbate nutrient deficiencies.
– People with chewing or swallowing difficulties – Blending produces a smoothie-like texture that may be easier to consume and digest.
– Those with chronic kidney disease – Excess potassium, magnesium, and oxalates from some juices could accumulate.
When in doubt, talk to your healthcare provider about whether juicing is appropriate for your individual health status and needs.
Tips for Beginners
Here are some tips if you’re new to juicing:
– Start slow – Try one juice per day in combination with your regular meals to see how your body responds.
– Go easy on fruit – Stick to mostly non-starchy vegetables and greens to minimize blood sugar spikes. Add lemon or lime for flavor instead of fruit.
– Drink immediately – Consume juice right after making it to preserve nutrients which degrade over time.
– Rinse produce – Wash all produce thoroughly before juicing to remove dirt, pesticides, and microbes.
– Rotate produce – Vary the fruits and veggies you juice to get a diversity of nutrients and prevent boredom.
– Skip peels – Remove peels, rinds, and pits which could introduce toxins or chemicals.
– Use organic – Choose organic produce when possible to minimize pesticide residues concentrating in juice.
– Add protein – Mix in plant-based protein like nuts, seeds, or legumes to help with satiety.
– Drink water after – Rinse your mouth and stay hydrated by drinking water following acidic juices.
– Monitor effects – Pay attention to energy, hunger levels, and how your body feels to assess juicing impacts.
Sample Juice Recipes
Here are a few healthy, balanced juice recipe ideas to try:
Green Detox Juice
– 1 cucumber
– 2 celery stalks
– 2 cups kale
– 1/2 lemon
– 1 inch ginger
– 2 apples
Beet Juice Boost
– 3 beets
– 2 carrots
– 1 apple
– 1 inch turmeric
– 1/2 lemon
– Dash of cinnamon
Tropical Green Juice
– 2 cups spinach
– 1/4 pineapple
– 1/2 banana
– 1/2 cup coconut water
– 1 tsp spirulina powder
– 1/2 lemon
Purple Power Juice
– 1 beet
– 1 cup blueberries
– 1 cup strawberries
– 1 orange, peeled
– 2 cups watercress
– 1 tsp honey (optional)
You can alter quantities and customize recipes with your favorite produce. Try adding fresh herbs, spices, celery, fennel, peppers, or tomatoes for flavor.
Should You Try Juicing?
Juicing can be a healthy way to hydrate, increase produce intake, get creative in the kitchen, and consume a wide variety of nutrients and plant compounds. But the benefits depend heavily on what and how you juice.
Focus on veggie juices over fruit-based to minimize blood sugar spikes. Alternate with whole fruits and veggies rather than replacing meals entirely. Drink immediately and combine with protein, fat, fiber, minerals, and hydration from other sources.
Avoid prolonged juice fasts or cleanses which could deprive your body of balanced nutrition. And consult your doctor if you have any underlying health conditions prior to juicing.
Used wisely to supplement your diet, juicing can help boost nutrition without requiring digestion of all that fibrous plant material. Just be mindful of your ingredients, portions, and listen to your body’s response.
References
1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723659/
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6251269/
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6471315/
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6048979/
5. https://care.diabetesjournals.org/content/27/12/2990
6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6164885/
7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6104959/
8. https://pubmed.ncbi.nlm.nih.gov/30669017/
9. https://www.ewg.org/foodnews/dirty-dozen.php
10. https://casereports.bmj.com/content/2017/bcr-2017-221854.full
11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4644573/
12. https://academic.oup.com/ajcn/article/78/3/526/4690007
13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4207053/
14. https://ascopubs.org/doi/pdf/10.1200/JCO.2004.42.624
Conclusion
In summary, juicing can provide benefits like enhanced nutrient absorption, improved hydration, and increased intake of fruits and veggies. But there are also drawbacks to consider, including potential nutrient deficiencies, blood sugar spikes, loss of fiber, and tooth erosion. Moderating juice portions, using mostly non-starchy veggies, and pairing juices with whole foods and water can help mitigate these downsides. Juicing may not be suitable for everyone, so talk to your doctor if you have any health conditions prior to starting a juicing regimen. Overall, juice can be a healthy supplement but not replacement for a balanced, diverse diet.
