By: Dr. John Bagnulo, Director of Nutrition

Ample research supports the relationship between dietary sugar, as found in fruit juice, and childhood obesity and increased insulin resistance. But emerging evidence suggests even more damaging health effects.

Sugar fuels inflammation in several ways. Research indicates that sugar both elevates insulin-mediated inflammation and produces significant shifts within our microbiome (the four to five pounds of microbial life in our gastrointestinal tract), which influences our immune system activity.

More recent studies have shown that our lungs contain several types of bacteria, and often fungi, that are also highly sensitive to the sugar in our diet, as well as our immune function.

As insulin and inflammation get turned up in a child’s body, normal environmental and microbial challenges to the lungs create a hyperactive immune response that can persist long after the "threat" has passed. So although pollen, dust, or microbes are usually blamed, the overly primed inflammatory pathway creates the perfect storm known as asthma.

Now we know that, in many cases, dietary sugar from fruit juice can be part of this storm for some children.

Regular consumption of refined sugars has so many systemic effects (primarily from increased insulin production) in kids that we sometimes fail to look beyond the threat of diabetes.

Fruit juice has a reputation for being healthy source of nutrients and antioxidants. Unfortunately, this public image (mostly the result of decades of marketing) has created health issues for many families. Fruit juices often contain marginal amounts of micronutrients (many are fortified with vitamin C), and have lost the majority of their antioxidants during the pasteurization process.

Of course, even if our children do not have asthma or another autoimmune or inflammatory-based condition, we should minimize their juice consumption in favor of whole, fresh or frozen fruits, which produce very different metabolic responses.

One of the best ways to incorporate healthy fruits is to start with berries and/or citrus fruits, which have the greatest ratio of potassium and other micronutrients to sugar (and, more specifically, fructose).

Frozen berries can be blended with an avocado or almond butter to create the foundation for a very healthy smoothie. Smoothies are also a great way to incorporate leafy green vegetables, such as spinach and lettuce, which might help kids look forward to eating more plants!

For more information on the damaging effects of regular juice consumption (even 100-percent juice products) in children, see the references below.

Dr. John Bagnulo is the Director of Nutrition at Functional Formularies and leads nutrition research and development initiatives. Learn more about Dr. Bagnulo here.



Berentzen NE et al. Associations of sugar-containing beverages with asthma prevalence in 11-year-old children: the PIAMA birth cohort. Eur J Clin Nutr. 2015 Mar;69(3):303-8. doi: 10.1038/ejcn.2014.153. Epub 2014 Aug 13.

Elevated blood pressure and triglycerides in young children

Kell KP et al. Added sugars in the diet are positively associated with diastolic blood pressure and triglycerides in children. Am J Clin Nutr. 2014 Jul; 100(1): 46–52. Published online 2014 Apr 9. doi: 10.3945/ajcn.113.076505

Unhealthy Weight Gain

DeBoer MD et al. Sugar-Sweetened Beverages and Weight Gain in 2- to 5-Year-Old Children. Pediatrics. 2013 Sep; 132(3): 413–420

Tight glycemic control and shorter ICU stays for children

Van den Berghe G et al. A Trial of Hyperglycemic Control in Pediatric Intensive Care N Engl J Med 2014; 370:1354-1356