“Getting your vegetables every day?” the personal trainer in the V8 commercial asks her client as he does sit-ups. “When I can,” he responds. That’s when the trainer gives the client a slap on his forehead.
“Could’ve had a V8,” says the ad. “2 full servings of vegetables for only 50 delicious calories.”
“Maybe you don’t have time to sit down for a salad,” says the Bolthouse Farms website. “Maybe you like using straws whenever possible. Whatever the case, we’ve juiced some kale, spinach, cucumbers and romaine lettuce and put them all into our Daily Greens.”
Yet Daily Greens has more pear juice than any other ingredient. After that come cucumber juice and celery juice—not the nutrient-rich green leafy vegetables that are linked to a lower risk of type 2 diabetes, heart attack, and stroke.
distinguishing juice from fruit
“Fruit juices get lumped in with fruits and vegetables in most studies,” says Lydia Bazzano, who directs the Center for Lifespan Epidemiology Research at the Tulane University School of Public Health and Tropical Medicine.
But not in Bazzano’s study, which tracked more than 71,000 female nurses for 18 years. For every three servings of whole fruit the women ate, their risk of type 2 diabetes dropped by nearly 20 percent. And each serving of leafy green vegetables was linked to roughly a 10 percent drop in diabetes risk.
But that was not the case for juice.
“For each daily serving of fruit juice, we found an 18 percent higher risk of type 2 diabetes,” says Bazzano. And that’s for a cup (8 ounces). “They sell juices in 16- or 20-ounce bottles out of a vending machine,” notes Bazzano. So it’s not hard to get more than two servings in one bottle.
“We saw an increased risk for orange and grapefruit juice, but it was strongest for apple juice,” adds Bazzano.
How might fruit juice raise the risk of diabetes?
“When you drink fruit juices, you’re less likely to compensate for the calories later on,” says Bazzano. “It’s the same thing that happens with sugar-sweetened beverages.” In other words, if you drink 150 calories of juice before or with a meal, you’re unlikely to compensate by eating 150 fewer calories of food.
But Bazzano saw the higher diabetes risks after accounting for any impact fruit juice might have had on weight gain. So something else had to explain the link.
“Fruit juices provide a heavy sugar load in a liquid form, so you have faster absorption,” notes Bazzano. “That rapid absorption might increase the insulin required to get that sugar out of your bloodstream and into your muscles and other parts of your body,” she adds.
“If you have that rapid insulin spike regularly, it might cause problems with your ability to produce enough insulin. That’s particularly true if you’re on the heavier side, and you already require larger amounts of insulin because you are insulin resistant.”
A vegetable juice (like Original V8) provides less of a sugar load than fruit juice does, so it’s likely to cause less of an insulin spike. But you’re still better off eating your veggies than drinking them because liquid calories don’t curb your appetite as well as solid foods.
The bottom line: Eat, don’t drink, your fruits and vegetables. If you want a smoothie, make your own from frozen fruit and vegetables (and maybe some low-fat milk or yogurt if you like it creamy).
Sources: J. Natl. Cancer Inst. 96: 1577, 2004; 7 Eur. J. Clin. Nutr. 66: 1082, 2012; Diabetes Care 31: 1311, 2008.