Juice, like fruit juice, is amazingly nutritious just as long as it is taken in moderation. Others may not be a total fan of eating fresh fruits, drinking fruit juice can be a good way to get one or two servings of fruit into your day and increase the amount of antioxidants you consume. Fruit juice can be high in calories, so it’s important to watch your serving size. It’s also important to go for 100 percent fruit juice rather than soft drinks made with fruit juice because that makes it easier to get better nutritional value and not just empty calories (1). Fruit juice has about the same vitamin and mineral content as fresh fruit and contains the same beneficial plant chemicals — such as flavonoids — found in fresh fruit. The main difference is that the fruit juice doesn’t have the fiber found in fresh fruit. So, if you’re craving a sweet drink, fruit juice is a much healthier option than soda or energy drinks (2).

What is D-Mannose?

One of the most tried fruit juice is the cranberry juice. It is made from cranberries, members of the Ericaceae family, one of the native fruits of North America (3). The Latin name for the cranberry plant is Vaccinium macrocarpon. Cranberries have a tremendous amount of antioxidant capacity as compared with other vegetables and fruits, such as broccoli, spinach, or apples. One cup of cranberries measures a total of 8983 antioxidant capacity (4). Most moms at home probably must have tried cranberry juice as home remedy for urinary tract infections (UTIs). But what it is about cranberries that make them so potentially valuable? The substance behind cranberries’ claim to fame for urinary tract health is a sugar called D-mannose (5).

D-mannose is also naturally found in fruits like apples, blueberries, peaches, oranges, and pineapple. It may be in the same family as other sugars such as fructose, glucose, lactose, and sucrose, but D-mannose acts much differently in your body. It is absorbed at a slower rate in the gastrointestinal tract. It is known as a glyconutrient, making it a health-promoting sugar (6). It has a lower glycemic index than glucose, as after it’s consumed it needs to be converted into fructose and then glucose, thereby reducing the insulin response and impact on your blood sugar levels (7).

D-Mannose Health Benefits

D-mannose is known for its many health benefits. One of the most talked about health benefits of D-mannose is its potential for helping to maintain urinary tract health. In a study, it is estimated that one in two women will be faced with urinary tract infections (UTI) during their lifetime and one in five women will be troubled not once, but repeatedly with recurrent UTI (8). D-Mannose is said to be an effective supplement for both treatment and prevention of UTIs. As a naturally occurring sugar that is found in a number of fruits, including apples, blueberries, and cranberries, it is effective because it attaches to E. coli bacteria, causing them to stick to each other and preventing them from sticking to the walls of the urinary tract (9). E. coli is a normal bacteria found in the gastrointestinal system but it does not belong in the urinary tract. Overgrowth of E. coli in the urinary system will lead to an infection (10). D-mannose specifically eliminates this bacteria from the body during urination. Some researches confirm that taking D-mannose regularly can significantly raise your blood mannose levels, which is a key to raising your urinary mannose levels. Optimal urinary levels are important for the support of your overall urinary tract health (11). In addition, our body does also produce mannose on its own yet taking supplemental d-mannose could be an option to raise your blood mannose levels and boost urinary mannose levels which can be very helpful in preventing urinary tract infections from occurring in the first place (12). According to a 2014 study published in the World Journal of Urology by Bojana Krancec et al., the use of d-mannose resulted in a significantly lower risk of side effects for women with urinary tract infections, as compared to a pharmaceutical solution, nitrofurantoin (13).

Researchers were surprised to find that D-mannose may be able to prevent and suppress type 1 diabetes, a condition in which the body doesn’t produce insulin — a hormone that’s needed to get glucose from the bloodstream into the body’s cells (14). A new study led by Dr. Wanjun Chen using a mouse model of autoimmune diabetes suggests that D-mannose is a ‘healthy’ or ‘good’ sugar that may be a safe dietary supplement. It is also revealed in the study that the relationship found between D-mannose and diabetes suggests that it may be used to prevent and suppress a number of allergies and immune diseases without any adverse effects on humans (15).

Some studies suggest that D-mannose may be useful as a “prebiotic”. Prebiotics are substances that promote the growth of beneficial bacteria in your gut (16). It supports your health by helping to raise levels of beneficial bacteria. According to research, D-mannose expresses both pro- and anti-inflammatory cytokines and has immunostimulating properties. When D-mannose was taken with probiotic preparations, they were able to restore the composition and numbers of indigenous microflora in mice (17). A strong evidence suggests that D-mannose may help also protect against lectins in your gastrointestinal tract. Lectins are proteins found in beans, seeds, grains, and even some vegetables and fruits. These carbohydrate-binding proteins present a challenge to digestion because they are not broken down by stomach acid or digestive enzymes (18). Studies show that D-mannose may help bind and block lectins, and prevent them from reacting with and damaging your intestinal wall (19).

Surely, D-mannose can be really helpful to us especially when confronted with urinary tract infections. This is, however, easy to find supplements in both online and in some health food stores. At this time, more research is needed to determine the optimal D-mannose dosage. Therefore, you should speak to your doctor before you begin using this simple sugar for the treatment of any health condition to avoid complications.