By Peter N. Landless and Zeno L. Charles-Marcel
I am a new Adventist trying to be a good steward of my health. A friend has been giving me health tips and insists that I start juicing and using more raw foods. I already enjoy a plant-based, whole-foods diet (amazingly!), and eat salads, beans, vegetables and fruits, and some raw seeds and nuts daily. So why should I be juicing?
More than 6 million people died worldwide in 2010 because they didn’t eat enough fruits and vegetables,* so your balanced, nutritionally appropriate, plant-based diet is good. Fruit-and-vegetable consumption varies among and within countries, often reflecting economic, cultural, and agricultural realities, but it remains low in many parts of the world. Juicing is one way for people to add more or new vegetables and fruit to their diet. Under usual circumstances, juicing provides no additional health benefits to chewing well what you would have used to make the juice, and it is often more expensive.
Juice contains most of the vitamins, minerals, and energy-providing and plant-derived (phyto) nutrients, but less overall nutrition than the whole fruits or vegetables from which it is extracted. This is because all the liquid (with its dissolved nutrients) is not extracted, and healthy fiber may be lost to the final product. Juiced nutrients are usually more available for absorption than that of the original food, but the benefit depends on the situation.
Scientific studies comparing fruit with commercially available fruit juice favor whole fruits. The act of chewing itself is healthful and is encouraged. Liquefying foods is appropriate in conditions that limit a person’s ability to bite, chew, swallow, or digest vegetables and fruits naturally. In conditions that benefit from higher-than-usual phytonutrient intake, liquefying—especially juicing—facilitates this. Whole or liquefied raw vegetables and fruits may benefit the gut bacteria and thus the body’s immune and metabolic (i.e., the body’s nutrient processing and energy-handling) systems.
When liquefying food is the issue, blending the food should be also considered. Blending is a method of whole-food liquefaction that preserves the natural fiber in the final product.
In one Korean study, blended apple, pear, persimmon, and mandarin orange retained greater antioxidant properties and beneficial compounds than juicing the fleshy parts. Fiber regulates intestinal absorption, so people with metabolic syndrome, prediabetes, and diabetes mellitus typically do better eating their calories than drinking them, and are less likely to overfeed. Blending produces heat, and may destroy some heat-sensitive nutrients while improving the absorption of others. For example, lycopene, a health-promoting phytonutrient in tomatoes, comes in two slightly different structural forms, and heat favors the one that is better absorbed.
Many individuals have benefited from short-duration “juice fasting.” When compared with calorie-reduced, standard Western diets, green-juice “fasting” is associated with better short-term weight management and fat loss—especially fat around and within the internal organs. In a small University of California, Los Angeles (UCLA) study in the United States, a three-day juice fast resulted in positive metabolic effects that lasted two weeks. Simulating water-only fasting with juices, etc., is associated with improved metabolic profiles in human studies.
In scientific studies, often the comparison is not between juices and the eating of fruits and vegetables, so currently there is no clear scientific evidence that extracted juices are necessary for health, or that they are clearly healthier than eating the vegetables or fruits themselves under normal circumstances.
So, to people all around the globe—even in North America, where 80 percent of people eat inadequate amounts of vegetables and fruits—I say, first eat enough veggies and fruits. Eat them in the “packaging” God has provided, and cook the vegetables, grains, and legumes as needed. Anything beyond that is optional.
* World Health Organization, September 2014, www.who.int/elena/titles/bbc/fruit_vegetables_ncds/en/.
Peter N. Landless, a board-certified nuclear cardiologist, is director of Adventist Health Ministries at the General Conference.
Zeno L. Charles-Marcel, a board-certified internist, is an associate director of Adventist Health Ministries at the General Conference.