We all know that eating whole fruits and vegetables is optimal for health. But, eating pounds and pounds of fresh produce isn’t always practical during a busy day. Enter juices. But, how do we choose the healthiest kind? Let’s look at the different types.

In traditional juicing methods (like the standard orange juice you buy at a grocery store), the liquid is heated to kill any potentially harmful bacteria or other microorganisms and prevent consumers from getting sick. This is called pasteurization, and the FDA has guidelines regarding required temperature and time depending on the type of ingredient used.

Fresh juices, like those found at a made-to-order juice bar, are prepared by putting fresh produce into a juicer with fast-spinning metal blades. The blades tear apart the produce and use centrifugal force to push the fruit/vegetable through a filter, which separates the juice from the flesh (pulp). These juices can also be pasteurized and sold commercially.

Critics claim that both of these processes could alter or destroy nutrients naturally found in the fruit, which never make it to the bottle. Because the metal blades heat up the juice, and the process exposes ingredients to air, they claim that it creates a less nutritious final product.

What about cold-pressed juice? These juicers use hydraulic presses to press fruits and vegetables through fine mesh to extract the liquid. They are called masticating juicers. This process differs from other methods because the ingredients are not exposed to heat or air.

But fresh and cold-pressed juices will only last 3-4 days before spoiling, and can pose a food safety risk. Therefore, commercially sold juice is bottled and submerged in water under high pressure to inactivate pathogens. This is another form of pasteurization, known as high-pressure processing, and allows companies to sell juice that will last 4-5 weeks. Any type of juice, regardless of how it was made (centrifugal or masticating juicer), can be pasteurized either way.

How much of a difference does this make in the nutritional content?

Some claim that, since cold-pressed juices minimize the exposure to heat and air, they’re able to hold onto more vitamins and minerals that are naturally present in the whole fruit. It is true that some vitamins degrade when exposed to air, heat or light. However, there is currently no published research to support claims that cold-pressed juices contain higher levels of vitamins or antioxidants.

Kate Di Prima, accredited practicing dietitian and spokeswoman for the Dietitians Association of Australia, told The Huffington Post Australia, "The main thing that comes from juice is vitamin C and it is sensitive to both heat and light. I guess that’s where this idea of cold-pressed juice being healthier comes from, as regular juice might have marginally decreased vitamin C because of the blade’s heat."

In order to fully understand how the cold-pressed process affects fruits and vegetables, each nutrient would have to be studied on its own, which is extremely difficult. And while vitamin C is affected by heat and light, many minerals like calcium, iron, and magnesium are not affected at all.

Because there isn’t good research to support the claim that cold-pressed juices are nutritionally better than other types, the choice is left to the consumer. Cost may play a factor, as cold-pressed/high-pressure processed juices are more expensive. If you are seeking this type of juice, make sure you check the label so that it is cold-pressed and high-pressure processed. A juice could be cold-pressed, for example, in the juicing process but then heat pasteurized, which essentially negates any potential benefit you may be seeking.

It’s also important to note that while juices can be a convenient way to supplement fruit and vegetable intake, whole fruits and vegetables remain preferable because they contain fiber, which many Americans are deficient in. Also, keep in mind that manufacturers will use buzzwords like “fresh” and “green” to earn your dollars. Many of these health terms are not defined or regulated, so they really do not mean anything. No matter what type of juice you choose, check the ingredient list to ensure the product is made from fruits and vegetables without added any sugar.

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