What Is Cranberry?
Cranberries, also known as cranberry or small cranberry, are referred to as “cranberry” because of their resemblance to the head and beak of a crane, as shown in the image.
Common Uses of Cranberries
Cranberries are primarily grown in the United States, Canada, and Chile. Historically, cranberries have been used for three main purposes: dye, cuisine, and medicine. Even before the scientific understanding of their composition, people recognized that cranberries had antibacterial properties. They were also used to treat scurvy, a condition caused by vitamin C deficiency during long sea voyages when fresh fruits were not available. In cuisine, cranberries are a common ingredient in Thanksgiving turkey dishes.
Nutritional Composition of Cranberries
Fresh cranberries are composed of approximately 86-87% water, 4-5% fructose, 2% insoluble fiber, 1.4% soluble fiber, 2.4% organic acids, and they also contain water-soluble vitamins B and C, as well as trace elements such as iron, iodine, manganese, and copper. Notably, cranberries contain various phytochemicals, including flavonoids, anthocyanins, catechins, and terpenes, which are considered the main components contributing to cranberry’s diverse health benefits.
Phytochemicals are secondary metabolites produced by plants for their survival and adaptability. These secondary metabolites can help plants ward off biological threats (some metabolites have scents that repel insects) or non-biological threats (some metabolites help the plant absorb ultraviolet light in strong sunlight).
Today, scientists have identified thousands of different phytochemicals, and many well-known compounds like lutein and curcumin are among them. While the functions of phytochemicals vary, they generally possess antioxidant and anti-inflammatory properties. Phytochemicals can be categorized into six major groups based on their structure:
- Flavonoids
- Phenolic Acids
- Phytoestrogens
- Organosulfur Compounds
- Carotenoids
- Other
💡Of particular interest in cranberries are the A-type proanthocyanidins (PACs), which fall under the first category and are considered the most effective components for preventing urinary tract infections (UTI). Type A PACs can prevent the adhesion of E. coli bacteria to bladder cells, thereby reducing infection rates [2].
Benefits of Cranberries
In terms of cranberry nutrition, the key health benefits come from phytochemicals. While cranberries do not directly kill bacteria, they influence the expression of bacterial fimbriae (hair-like structures on the surface of bacteria). These fimbriae act like grappling hooks used for attachment, allowing bacteria to adhere to various tissues and begin multiplying, causing infection. By reducing the adhesive properties of bacterial fimbriae, cranberries can lower the rate of cell infection.
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Prevention of Urinary Tract Infections
Urinary tract infections (UTIs) are common bacterial infections that occur primarily in women, with approximately 1 in 4 women experiencing a UTI. These infections are often caused by E. coli bacteria. Cranberries contain A-type proanthocyanidins (PACs), and research has shown that only type A PACs are effective in preventing UTIs [3]. A-type PACs can prevent the binding of E. coli bacterial fimbriae to bladder epithelial cell receptors, reducing E. coli adhesion [4]. This improvement is particularly noticeable in women with recurrent UTIs [5][6].
Learn more about UTIs: UTI Symptoms and Causes: 4 Effective Ways to Alleviate Urethral Inflammation!
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Prevention of Gastric Cancer and Ulcers
Infection by Helicobacter pylori is considered a major cause of gastric cancer, gastric inflammation, and ulcers. Cranberries contain large molecules known as non-dialyzable material (NDM) that consist of polyphenolic compounds and non-polyphenolic compounds [7]. NDM can prevent the adhesion of Helicobacter pylori to gastric mucosa, reducing the risk of gastric cancer [8]. In 2005, a study involving 189 adults found that daily consumption of 500 mL of cranberry juice significantly reduced Helicobacter pylori infection [9]. In vitro experiments found that polyphenols in cranberry extracts can effectively affect the morphology of Helicobacter pylori and inhibit its growth [10].
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Preventing Urinary Tract Infections
Urinary tract infections are one of the common bacterial infections, second only to respiratory infections. They are more common in women, with statistics showing that approximately 1 in 4 women will experience a urinary tract infection. The most common bacteria responsible for these infections is Escherichia coli (E. coli). Cranberries contain type A proanthocyanidins (PACs), and experimental results have shown that only type A PACs are effective in preventing urinary tract infections [3]. Type A PACs can prevent the attachment of E. coli fimbriae to bladder epithelial cells, reducing E. coli adhesion [4]. This improvement is particularly significant in women with recurrent urinary tract infections [5][6].
Further reading: Symptoms and Causes of Urinary Tract Infections, 4 Effective Ways to Improve Urethritis!
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Preventing Stomach Cancer and Ulcers
Infection with Helicobacter pylori is considered a major cause of stomach cancer, gastritis, and ulcers. Cranberries contain non-dialyzable material (NDM), which includes polyphenolic compounds and non-polyphenolic compounds [7]. This can prevent Helicobacter pylori from attaching to the stomach mucosa, reducing the risk of developing stomach cancer [8]. In a study from 2005, 189 adults who consumed 500 milliliters of cranberry juice per day were found to significantly reduce Helicobacter pylori infection [9]. In vitro experiments have shown that polyphenols in cranberry extracts can effectively influence the morphology of Helicobacter pylori and inhibit its growth [10].
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Oral Health
Porphymonas gingivalis is a Gram-negative oral bacterium responsible for causing periodontal inflammation. It adheres to the surface of teeth and gum epithelial cells through a series of adhesive proteins. NDM in cranberries effectively prevents the colony formation of P. gingivalis, preventing periodontal disease [11].
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Heart Health
Cranberries contain various phytochemicals, such as polyphenolic compounds, anthocyanins, proanthocyanidins, and quercetin, all of which have strong antioxidant properties. Cranberry juice or its extracts have been shown to potentially reduce the risk of cardiovascular events through multiple mechanisms, such as lowering lipid levels, inhibiting inflammation [12], improving endothelial function, increasing HDL cholesterol, reducing LDL cholesterol, and decreasing LDL cholesterol oxidation [13]. This contributes to heart health.
Precautions and Side Effects of Consuming Cranberries
Moderate consumption of cranberries and cranberry products is generally safe for most people, but excessive intake can lead to stomach discomfort and diarrhea.
The impact of cranberries on kidney stones is not consistent in research results, with both positive and negative findings reported [14][15]. Most kidney stones are made of calcium oxalate, and high oxalate levels in urine are a major contributing factor. Berries, including cranberries, have relatively high oxalate content, and excessive consumption may increase the risk of kidney stones. Therefore, it is recommended that individuals with a family history of urinary stones should avoid excessive intake. However, moderate supplementation of cranberries and related products does not increase the risk of urinary stone formation.
Individuals taking anticoagulant medications such as Warfarin should avoid taking cranberries concurrently with their medication, as certain components of cranberries can interfere with the medication’s effectiveness and affect its potency [16].
Who Needs Cranberry Supplements and What Dosage is Helpful?
Currently, the most complete part of cranberry efficacy experiments focuses on reducing urinary tract infections, with a recommended minimum of 36 milligrams of type A proanthocyanidins [17].
💡When choosing cranberry-related products, it is also recommended to opt for complex formulations. Other health-promoting ingredients for urinary tract infections, such as probiotics, D-mannose, etc., can be considered.
Further reading: 3 Benefits and Side Effects of D-Mannose (A Must-Read for Women)
Conclusion
Many consumers may have had limited knowledge of cranberries in the past, with most thinking that cranberries are only beneficial for
women. However, through this article’s introduction, you may have gained a broader and deeper understanding of cranberry-related products, allowing everyone to have the opportunity to explore them.
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