Juicing fruits and vegetables

nutrition | July 1, 2017 | Author: Naturopath

Digestion

Juicing fruits and vegetables

Australians are recommended to eat a minimum of 5-6 serves of vegetables per day and 2 serves of fruit per day. The message has been there for years: Eat your veggies; Eat more veggies; Eat a variety of veggies.

Vegetables and fruit are rich sources of vitamins, minerals, dietary fibre and thousands of phytonutrients, also called phytochemicals. These are naturally occurring plant chemicals that protect the plant from pests and give it its colour, odour, and flavour. Phytochemicals help prevent disease and promote health in humans.

Studies show that people who eat relatively high amount of fruit and vegetables have reduced risk of chronic diseases such as diabetes, heart disease, and cancer.

juicingDrinking your fruits and vegetables

Juicing is a process that extracts water and nutrients from produce and discards the indigestible fibre.

The question remains: Is juicing as healthy as eating whole fruits and vegetables?

Kris Carr, a New York Times best-selling author, speaker and wellness advocate, is considered by many to be the ‘queen of juicing’. Carr explains that the lack of fibre in juices means that your body does not have to work as hard to digest the fibre, and can therefore easily pull the vitamins, minerals and phytonutrients straight into your bloodstream. Furthermore, you can fit a lot more in a green juice than if you were to eat the fruits and vegetables whole.

But isn’t fibre important?

High-fibre diets are associated with higher diversity and abundance of gut bacteria.

juicing vegetablesThis is contributed, in part, to increased production of short-chain fatty acids. Short-chain fatty acids are produced by the gut bacteria as a byproduct of fermentation of dietary fibre and play a role in stimulating immune function as well as exert anti-inflammatory effects.

Consumption of adequate or large amounts of dietary fibre is associated with a lower incidence of inflammatory disease, including colitis, type 2 diabetes and colon cancer.

Dr Michael Greger, author of “How not to Die” and a proponent of plant-based and whole food diets, claims that juicing removes more than just fibre. Fruits and vegetables contain a group of health-promoting phytochemicals called polyphenols, some of which are non-extractable, meaning they are locked to the fibre and are removed with the fibre by juicing.

Dr Greger suggests that smoothies are preferable to juices, as unlike juices, smoothies consist of the entire fruit or vegetable and contain all of the fibre.

Does juicing affect blood sugar?

In the absence of fibre, drinking fruit juice spikes blood sugar levels more and faster than eating whole fruit.

juicing diabetesOne large study found that greater consumption of fruit juice was significantly associated with a higher risk of type 2 diabetes, whereas substitution of whole fruits for fruit juice was associated with a lower risk.

In order to avoid blood sugar spikes, Kris Carr suggests keeping your juices green, meaning drinking vegetable-only juices, as they are lower in sugar.

You can enhance their flavour with a splash of lemon, lime, or ginger.

What about nutrient degradation?

Degradation is the process in which vitamins and enzymes break down or deactivate, and as a result lose their nutritional value. Some vitamins and enzymes are sensitive to heat, light, and oxygen, making them susceptible to loss during and after juicing.

juicing hand juicerHeat. The slower the juice is extracted, the less heat is produced, and the more nutrients are preserved.

The type of juicer you use can make a difference. Centrifugal-type juicers are the most common and affordable electrical juicers on the market. However, they spin at high speed, which generates more heat, destroying some of the enzymes.

 

Non-centrifugal or masticating juicers operate at slower speed. This process produces less heat, thus maintaining more of the nutrients intact. However, this type of juicer is much more costly.

Oxidation. Exposure to oxygen can affect the quality of the nutrients and the flavour of the juice.

To minimize oxidation, consume the juice as quickly as possible, within 15-20 minutes of juicing. Alternatively, juices made in a non-centrifugal juicer can last longer, according to the manufacturer. Store the juice in an airtight container in your fridge, for up to about 24-48 hours.

References

Greger, M. (2014) Juicing removes more than just fibre, NutritionFacts.org - Latest in Clinical Nutrition: Volume 21, retrieved June 21, 2017,

Kris Carr 2017, How to Make a Green Juice: Video, Recipe & Juicing FAQs, retrieved June 21, 2017,

Linus Pauling Institute - Oregon State University 2009, Fruit and Vegetables, Linus Pauling Institute, retrieved June 21, 2017,

Muraki, I., Imamura, F., Manson, J. E., et al. (2013). Fruit consumption and risk of type 2 diabetes: results from three prospective longitudinal cohort studies. BMJ (Clinical Research Ed.), 347, f5001.

National Health and Medical Research Council 2013, Eat for Health - Australian Dietary Guidelines. NHMRC, retrieved June 21, 2017,

 

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