Recent observational and clinical studies have raised interest in the
potential health effects of cranberry consumption, an association that
appearsto be due to the phytochemical content of this fruit. The profile of
cranberry bioactives is distinct from that of other berry fruit, being
rich in A-type proanthocyanidins (PACs) in contrast to the B-type PACs present
in most other fruit. Basic research has suggested a number of potential
mechanisms of action of cranberry bioactives, although further molecular
studies are necessary. Human studies on the health effects of cranberry
products have focused principally on urinary tract and cardiovascular
health, with some attention also directed to oral health and
gastrointestinal epithelia. Evidence suggesting that cranberries may decrease the
recurrence of urinary tract infections is important because a nutritional
approach to this condition could lower the use of antibiotic treatment
and the consequent development of resistance to these drugs. There is
encouraging, but limited, evidence of a cardioprotective effect of
cranberries mediated via actions on antioxidant capacity and lipoprotein
profiles. The mixed outcomes from clinical studies with cranberry
products could result from interventions testing a variety of products,
often uncharacterized in their composition of bioactives, using different
doses and regimens, as well as the absence of a biomarker for compliance
to the protocol. Daily consumption of a variety of fruit is necessary to
achieve a healthy dietary pattern, meet recommendations for micronutrient
intake, and promote the intake of a diversity of phytochemicals. Berry
fruit, including cranberries, represent a rich source of phenolic bioactives
that may contribute to human health.

Emerging science supports therapeutic roles of strawberries, blueberries, and cranberries in metabolic syndrome, a prediabetic state characterized by several cardiovascular risk factors. Interventional studies reported by our group and others have demonstrated the following effects: strawberries lowering total and LDL-cholesterol, but not triglycerides, and decreasing surrogate biomarkers of atherosclerosis (malondialdehyde and adhesion molecules); blueberries lowering systolic and diastolic blood pressure and lipid oxidation and improving insulin resistance; and low-calorie cranberry juice selectively decreasing biomarkers of lipid oxidation (oxidized LDL) and inflammation (adhesion molecules) in metabolic syndrome. Mechanistic studies further explain these observations as up-regulation of endothelial nitric oxide synthase activity, reduction in renal oxidative damage, and inhibition of the activity of carbohydrate digestive enzymes or angiotensin-converting enzyme by these berries. These findings need confirmation in future studies with a focus on the effects of strawberry, blueberry, or cranberry intervention in clinical biomarkers and molecular mechanisms underlying the metabolic syndrome.

Berries are a good source of polyphenols, especially anthocyanins, micronutrients, and fiber. In epidemiological and clinical studies, these constituents have been associated with improved cardiovascular risk profiles. Human intervention studies using chokeberries, cranberries, blueberries, and strawberries (either fresh, or as juice, or freeze-dried), or purified anthocyanin extracts have demonstrated significant improvements in LDL oxidation, lipid peroxidation, total plasma antioxidant capacity, dyslipidemia, and glucose metabolism. Benefits were seen in healthy subjects and in those with existing metabolic risk factors. Underlying mechanisms for these beneficial effects are believed to include upregulation of endothelial nitric oxide synthase, decreased activities of carbohydrate digestive enzymes, decreased oxidative stress, and inhibition of inflammatory gene expression and foam cell formation. Though limited, these data support the recommendation of berries as an essential fruit group in a heart-healthy diet.

The American cranberry (Vaccinium macrocarpon) is one of the three commercially important fruits native to North America. Cranberries are a particularly rich source of phenolic phytochemicals, including phenolic acids (benzoic, hydroxycinnamic, and ellagic acids) and flavonoids (anthocyanins, flavonols, and flavan-3-ols). A growing body of evidence suggests that polyphenols, including those found in cranberries, may contribute to reducing the risk of cardiovascular disease (CVD) by increasing the resistance of LDL to oxidation, inhibiting platelet aggregation, reducing blood pressure, and via other anti-thrombotic and anti-inflammatory mechanisms. Research regarding the bioactivity of cranberries and their constituents on risk factors for CVD is reviewed.

Growing evidence from tissue culture, animal, and clinical models suggests that the flavonoid-rich fruits of the North American cranberry and blueberry (Vaccinium spp.) have the potential ability to limit the development and severity of certain cancers and vascular diseases including atherosclerosis, ischemic stroke, and neurodegenerative diseases of aging. The fruits contain a variety of phytochemicals that could contribute to these protective effects, including flavonoids such as anthocyanins, flavonols, and proanthocyanidins; substituted cinnamic acids and stilbenes; and triterpenoids such as ursolic acid and its esters. Cranberry and blueberry constituents are likely to act by mechanisms that counteract oxidative stress, decrease inflammation, and modulate macromolecular interactions and expression of genes associated with disease processes. The evidence suggests a potential role for dietary cranberry and blueberry in the prevention of cancer and vascular diseases, justifying further research to determine how the bioavailability and metabolism of berry phytonutrients influence their activity in vivo.

Atherosclerosis is the deposition of plaques containing cholesterol and lipids in arterial walls. Atherosclerosis causes cardiovascular disease that lead to heart attacks and stroke. Mortality from these diseases is the leading cause of death in the U.S. Atherogenisis starts with the uptake of oxidized LDL by endothelial macrophages, the accumulation of foam cells in the intima of the artery and the formation of fatty streaks. Research indicates that consumption of flavonoids in foods and beverages may decrease the risk of atherosclerosis. In vitro and in vivo experiments with flavonoids demonstrate that flavonoids are dietary antioxidants and inhibit LDL oxidation, inhibit platelet aggregation and adhesion, inhibit enzymes involved in lipid and lipoprotein metabolism that affect the immune response to oxidized LDL and their uptake by endothelial macrophages, may induce endothelium-dependent vassorelaxation, and may increase reverse cholesterol transport and decrease total and LDL cholesterol. Cranberries contain both hydroxycinnamic acids and flavonoids. The cranberry flavonoids belong to three groups: anthocyanins, flavonols, and proanthocyanidins. This article reviews the literature on the effects of flavonoids on atherosclerosis with an emphasis on the potential effects of the flavonols and proanthocyanidins in cranberries.

Eating a healthy balanced diet, is one of the most important and relevant ways to delay and prevent various health complications including cardiovascular disease (CVD). Among the nutritional factors that have been investigated in recent years, dietary fat intake may be the one that has been most targeted. However, there is also clear epidemiological evidence that increased fruits and vegetables intake can significantly reduce the risk of CVD, an effect that has been suggested to be resulting to a significant extent, from the high polyphenol content of these foods. Numerous polyphenolic compounds such as flavonoids have been identified as having strong antioxidant properties. Most interesting is the fact that, in addition to being one of the largest groups of antioxidant phytochemicals, flavonoids are also an integral part of the human diet as they are found in most fruits and vegetables. Cranberries are one of the most important sources of flavonoids that have a strong antioxidant and anti-inflammatory capacities. Thus, consumption of cranberries or their related products could be of importance not only in the maintenance of health but also in preventing CVD. The following review will present evidences supported for the most part by clinical observations that cranberries can exert potentially healthy effects for your heart.