Juicing Pros & Cons


Juicing is all the rage these days. When your favorite green drink can cost upwards of $7.00, juicing can be an enormous business opportunity and a potential drain on the wallet at the same time. So, when you down that $7.00 juice - or spend 30 minutes juicing your own concoction, is it worth it?

Fruit and vegetable intake has been proven to be an important component of a healthy diet that is associated with a decreased risk of numerous chronic diseases and metabolic syndromes. The 2010 Dietary Guidelines for Americans, released by the USDA, places an increased emphasis on intake of fruits and vegetables, with fruits and vegetables comprising one half of the plate from the MyPlate dietary guide. However, according to the State Indicator Report on Fruits and Vegetables released by the CDC in 2013, the American national median intake of fruits and vegetables is 1.1 and 1.6 times per day, respectively. Complementary to the previous statistics, nearly 37% of Americans reported consuming fruits less than one time daily and about 23% of Americans reported consuming vegetables less than one time daily (CDC, 2013). So, can juicing be an acceptable supplement or even replacement for whole fruit and vegetable intake?

In 2010, a study was carried out to determine if the incorporation of a vegetable juice could be a practical way for individuals to increase vegetable consumption, meet dietary recommendations for daily vegetable intake, and positively impact markers of cardiovascular health. (Shenoy et al., 2010). Subjects were divided between three treatment groups assigned to drink 8 fluid ounces, 16 fluid ounces, or no vegetable juice per day. Despite being educated on the Dietary Approaches to Stop Hypertension (DASH) diet, the subjects' average daily intake of vegetables did not meet recommendations at any point during the study. Aside from the juice, dietary intake of vegetables was similar among the three groups. However, the incorporation of vegetable juice significantly increased the total daily intake of vegetables to an average of 4.3 and 6.5 servings of vegetables in the 8 and 16 fluid ounce groups, respectively (Shenoy et al., 2010). This increase in vegetable intake supports the concept that daily consumption of a vegetable juice is a feasible way to assist an individual in meeting his/her daily recommendation of vegetable intake. Although vegetable consumption was enhanced in those consuming the juice, no significant changes were observed in the study's target vascular health parameters - including blood pressure, cholesterol, and other lipid profiles.

Obesity associated disease states like metabolic syndrome and type 2 diabetes are often associated with increased intakes of liquid calories. In 2013, Eshak et al. conducted a community-based, prospective cohort study with a large number of middle-aged Japanese men and women using a 44-item food frequency questionnaire. The purpose of the study was to examine the association of the intake of soft drinks (cola, flavored juices, and non-100% fruit juices), 100% fruit juice and vegetable juices with the risk of type 2 diabetes. During the 10-year follow-up, no associations were observed between 100% fruit or vegetable juices intakes and risk of type 2 diabetes in either men or women (Eshak et al., 2013). Additionally, the findings of this study indicate that the intake of non-100% fruit juices, but not 100% fruit juices, was associated with risk of type 2 diabetes, which is consistent with the findings from the Nurses' Health Study II. In the Nurses' Health Study II, fruit punch was associated with risk of type 2 diabetes, but not 100% fruit juice. Similarly, the Black Women's Health Study found that fruit drinks (80% sweetened and 20% unsweetened) were associated with risk of type 2 diabetes, but not 100% orange and grape juices. The authors propose that the natural sugars in the 100% fruit juices may have different metabolic effects than the high fructose corn syrup added to non 100% juices (Eshak et al., 2013).

Related to the differences noted between 100% fruit and vegetable juices and non-100% fruit and vegetable juices, there also seems to be various differences in whole fruits and vegetables versus processed fruits and vegetables. In the past, studies have examined the effect that processing fruits and vegetables has on satiety and energy intake versus whole fruit and vegetable consumption (Flood-Obbagy & Rolls, 2009). This study tested the effect on satiety and subsequent meal energy intake after consuming various forms of an apple matched for energy content, weight, energy density, and fiber content. The apple "pre-meals", which included peeled apple segments, applesauce, and apple juices with and without added fiber, were consumed before subjects were fed the test meal. Subjects were asked to rate their hunger and satiety after consuming the pre-meal ,the perceived calorie content ,and how filling they thought the pre-meal would be. Interestingly, meal intake was significantly different between experimental conditions. Subjects consumed significantly less energy from the test meal after eating apple segments compared to the applesauce and both juice preloads (Flood-Obaggy & Rolls, 2009). All four pre-meal treatment groups ate significantly less energy during the test meal compared to the control group which consumed no pre-meal. However, in the two juice treatment groups, total energy intakes at lunch did not differ significantly from each other (Flood-Obaggy & Rolls, 2009). Contrary to other studies proposing that the difference in energy intake was due to fiber content, the authors of this study concluded fiber content was most likely not the reason since the treatment groups were matched for fiber content. To further reinforce this reasoning, the authors did not notice a significant difference in satiety between apple juice with and without fiber. They proposed, however, that different forms of fruit may have different effects on satiety due to intrinsic structural properties that affect volume and chewing. Although their treatment groups were matched for energy content and weight, they believe the structure provided by intact cell walls makes whole apple larger in volume than applesauce and apple juice.

The processing of fruits and vegetables alters their structure and induces significant changes in chemical composition, nutritional value, and bioavailability of certain nutrients. For example, fruit juices have a lower content of fiber than raw fruit due to processing and breaking down of cellular structures like fiber within the skin of fruits. Cooking vegetables creates a loss of water-soluble and heat-sensitive bioactive compounds (Griep et al, 2010). However, processing can also increase availability of bioactive compounds, as evidenced by the effect of heat improving bioavailability of lycopene from tomatoes and carotenoids from carrots. Processing can also initiate the conversion of certain bioactive compounds into more bioavailable forms, much like the effect of processing on the conversion of folate polyglutamate in vegetables into the more bioavailable monoglutamate (Griep et al, 2010). A study examining the effects of vegetable juice processing on folate content revealed that there was no statistical difference of total folate in juiced vegetables and unprocessed vegetables (Wang, Riedl, and Schwartz, 2013). Comparing the content of folate within the pulp and juice of various vegetables, they found that folate content of juices was as high as raw vegetables for nearly all the vegetables they tested. Their study also showed that during juicing, folate polyglutamates in some vegetables were highly deglutamylated into the more bioavailable form of folate monoglutamate (Wang, Riedl, and Schwartz, 2013).

Although it is generally recommended to consume whole fruits and vegetables for vitamin and mineral intake, juicing and consuming juices has been considered as a viable supplement to dietary intake of whole fruits and vegetables. With this intake of juices, it has helped adults consume an amount of fruits and vegetables closer to the amount recommended in dietary guidelines, and improved some health markers of cardiovascular health. One study examined the difference in oxidative stress markers among healthy subjects with habitually low intake of fruits and vegetables (Khan et al, 2014). Their study used the supplementation of a high and low blackcurrant juice, and a placebo to examine their effects on flow-mediated dilation and plasma concentrations of F2-isoprostanes (high levels indicate more oxidative stress) and vitamin C. The groups of blackcurrant juice, a juice rich in antioxidants and polyphenols, had significantly increased flow-mediated dilation, plasma vitamin C concentrations, and lower concentrations of F2-isoprostanes than the placebo groups. With the results, the authors concluded that consumption of a blackcurrant juice drink high in vitamin C and polyphenols for 6 weeks can decrease oxidative stress and improve endothelial function in a population that generally consumes a low intake of fruits and vegetables (Khan et al, 2014). Similarly, another study conducted by George et al. had its subjects consume 400 ml of a fruit and vegetable puree-based drink (FVPD) after following a low-flavonoid diet for 5 days (George et al, 2013). The study examined the effects of ingestion of the puree drink on vasodilation, antioxidant status, phytochemical bioavailability and other CVD risk factors compared to a fruit-flavored sugar-matched control. The FVPD significantly increased plasma vitamin C and total nitrate/nitrite concentrations (George et al, 2013). Also during the 6 hours after juice consumption, the antioxidant capacity of plasma increased significantly and there was a simultaneous increase in plasma and urinary phenolic metabolites, along with significantly lower glucose and insulin peaks compared to the control (George et al, 2013). The authors concluded that pureed fruit and vegetable products are useful vehicles for increasing micronutrient status and plasma antioxidant capacity.

Alongside growing interest in polyphenol supplementation among the general adult population, there is also increasing interest in the effects of polyphenols in the context of muscle function and performance recovery. The rationale for this area of growing interest is that membrane lipids and proteins are damaged by oxidation reactions and the breakdown of myoglobin results in production of ferric acid. Exercise-induced radical production is too high for endogenous scavenging mechanisms and muscle micro-damage also induces neutrophil oxidative burst (Myburgh, 2014). In a study done in 2011, the effect of pomegranate juice supplementation on strength and exercise after eccentric exercise was examined. Using pomegranate juice supplementation and a placebo, the study found that elbow flexion strength was significantly higher during the 2- to 168-hour period postexercise with pomegranate juice compared to the placebo. Elbow flexor muscle soreness was also significantly reduced with pomegranate juice compared with that of placebo and at 48 and 72 hours postexercise (Trombold et al, 2011). The results indicated a mild, acute ergogenic effect of pomegranate juice in the elbow flexor muscles of resistance trained individuals after eccentric exercise (Trombold et al, 2011).

Although intake of whole fruits and vegetables is recommended to meet dietary guidelines of fruits and vegetables, fruit and vegetable juice supplementation seems to a viable option to increase intake. Juicing fruits and veggies may decrease the impact of certain nutrients and eliminate the fiber that our body needs for heart health, improved digestion and sustained energy, but overall, the vitamin, mineral, and phytonutrients found in 100% fruit and vegetable juice seems to be a beneficial "complement" and beneficial for the general population and athletes.

If you decide to try juicing to bolster your fruit and veggie intake, consider using a Vitamix ® so that you can use the whole fruit and maintain the benefits of the fiber and skin of many fruits and veggies. Here are a few recipes to try!

Colorful
  • 2 Full Medium Cucumbers
  • 2 Handfuls of Baby Carrots
  • 1 Medium Tomato
  • 1 Medium Red Bell Pepper

Healthy Sweet & Sour Beverage
  • 2 Medium Apples
  • 1 Lemon
  • 1 slice of Fresh Ginger

Tart Berry
  • ½ Large Cucumber
  • 1 Cup Spinach
  • ½ Cup Strawberries
  • ½ Med Green Apple
  • ½ Large Orange
  • ¼ Cup Pomegranate

Super Berry
  • 1 Cup Kale
  • 1 Cup Spinach
  • ½ Cup Strawberries
  • ¾ Cup Berry Mix (raspberries, blackberries, blueberries)
  • ½ Cup Pitted Cherries

Tropical
  • 1 Cup (total) Mango and/or Pineapple
  • ½ Large Orange
  • 1 Large Carrot
  • 3 Stalks Celery
  • ½ Lime
  • Coconut Water as desired to dilute

Ginger Pear
  • 1 Cup Spinach
  • 1 Cup Arugula or other green
  • ½ Medium Cucumber
  • 1 Medium Pear (cored)
  • ½ Large Orange
  • ½ inch piece of Ginger

Great Greens
  • 1 Cup Spinach
  • 1 Cup Kale
  • ½ cup green grapes
  • 1 Kiwi (peeled)
  • 3 Stalks Celery
  • Lime Juice as desired

Purple Power
  • 1 Cup Flowering Kale
  • ¾ Cup Blueberries
  • ½ Large Red Apple
  • ½ Medium Cucumber
  • 3 Stalks Celery
  • Lemon Juice As Desired to Finish

Raspberry Lime
  • 1 Cup Spinach
  • 1 Leaf Red Chard
  • ¾ Cup Raspberries
  • 1 Small Peach
  • ¼ Cup Pitted Peaches
  • ½ Lime (peeled)
  • 3 + Mint Leaves (to desired level of mint flavor)

References

Eshak, E. S., Iso, H., Mizoue, T., Inoue, M., Noda, M., & Tsugane, S. (2013). Soft drink, 100% fruit juice, and vegetable juice intakes and risk of diabetes mellitus. Clinical Nutrition, 32(2), 300-308.

Flood-Obbagy, J. E., & Rolls, B. J. (2009). The effect of fruit in different forms on energy intake and satiety at a meal. Appetite, 52(2), 416-422.

George, T. W., Waroonphan, S., Niwat, C., Gordon, M. H., & Lovegrove, J. A. (2013). Effects of acute consumption of a fruit and vegetable puree-based drink on vasodilation and oxidative status. British Journal of Nutrition, 109(08), 1442-1452.

Griep, L. M. O., Geleijnse, J. M., Kromhout, D., Ocké, M. C., & Verschuren, W. M. (2010). Raw and processed fruit and vegetable consumption and 10-year coronary heart disease incidence in a population-based cohort study in the Netherlands. PLoS One, 5(10), e13609.

Khan, F., Ray, S., Craigie, A. M., Kennedy, G., Hill, A., Barton, K. L., ... & Belch, J. J. (2014). Lowering of oxidative stress improves endothelial function in healthy subjects with habitually low intake of fruit and vegetables: A randomized controlled trial of antioxidant-and polyphenol-rich blackcurrant juice. Free Radical Biology and Medicine, 72, 232-237.

Myburgh, K. H. (2014). Polyphenol supplementation: benefits for exercise performance or oxidative stress?. Sports Medicine, 44(1), 57-70.

Shenoy, S. F., Kazaks, A. G., Holt, R. R., Chen, H. J., Winters, B. L., Khoo, C. S., ... & Keen, C. L. (2010). The use of a commercial vegetable juice as a practical means to increase vegetable intake: a randomized controlled trial.Nutrition Journal, 9(1), 38.

Trombold, J. R., Reinfeld, A. S., Casler, J. R., & Coyle, E. F. (2011). The effect of pomegranate juice supplementation on strength and soreness after eccentric exercise. The Journal of Strength & Conditioning Research, 25(7), 1782-1788.

Wang, C., Riedl, K. M., & Schwartz, S. J. (2013). Fate of folates during vegetable juice processing-Deglutamylation and interconversion. Food Research International, 53(1), 440-448.
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