6 Side Effects of Cranberry Supplements

6 Side Effects of Cranberry Supplements

The beneficial effects of cranberry supplements have long been recognized by health and nutritional experts. Cranberry contains phenols which are a type of antioxidant that works to fight off diseases, and its main function is to prevent and help repair damaged cells. It has antibacterial properties and has been widely used for the prevention and treatment of stomach ulcers, UTI and even dental plaque. As cranberry supplements contain more concentrated doses of the fruit, it is recommended to take them instead of drinking a lot of juice.

Common Side Effects of Cranberry Supplements

While cranberry has been used safely in research, there has been evidence that it also has side effects. These side effects are yet to be proven scientifically. Hence, these should not be reasons not to take cranberry supplements, at least if they are only taken in small doses, and as long as you don't have other conditions that may be affected by the intake of cranberries. Here are six of the main side effects of these supplements.

  • Gastrointestinal distress and diarrhea. This is the most common side effect reported. This is more often seen with excessive intake of the supplement.
  • Allergic reactions. Cranberries contain significant amounts of salicylic acid, which is similar to aspirin. If you are allergic to aspirin, you must avoid consuming large quantities of cranberry supplements. Anyone who is allergic to Vaccinium should stay away from these supplements.
  • High sugar content. Because many supplements contain a higher amounts of sugar, there are concerns for the development of diabetes. People suffering from diabetes should avoid supplements that contain added sugar.
  • Kidney stones. Cranberry extracts and juices contain high levels of a chemical compound called oxalate. Several scientific studies have shown that some cranberry supplements boost the level of oxalate in the urine by as high as 43%. Drinking an average of one liter a day of cranberry juice, or its equivalent, over a long period of time can trigger the formation of kidney stones. This will be due to the presence of the oxalate, which combines with calcium to form kidney stones. If your family has a history of kidney stones, you should avoid taking these supplements.
  • Negative interaction with drugs. Cranberry is known to have a negative effect on certain drugs like Warfarin. There may be interference with the effectiveness of the drug.

Cranberry supplements are not recommended for women who are pregnant or are breast-feeding, as taking the supplement has not yet been proven to be safe for them.

A Final Word on Dietary Supplements

Since the U.S. Food and Drug Administration does not impose regulating provisions for herbs and supplements, you should consult your doctor before taking cranberry supplements, especially for longer periods of time (i.e., more than one week).  Be careful when deciding to take the supplements on your own. Do your research and make sure you only buy supplements from a reputable company, and purchase supplements that actually have what you need.