Health Benefits
While familiar nutrients like vitamin C and fiber play a very important role in cranberry's health benefits, it's the amazing array of phytonutrients in cranberries that has gotten the special attention of health researchers. There are at least 5 key categories of health-supportive phytonutrients in cranberries, as summarized in the following chart:
Cranberry Phytonutrients
Type of PhytonutrientSpecific Molecules Phenolic Acidshydroxybenzoic acids including vanillic acids; hydroxycinnamic acids inculding caffeic, coumaric, cinnamic, and ferulic acids Proanthocyanidinsepicatechins Anthocyaninscyanidins, malvidins, and peonidins Flavonoidsquercetin, myricetin, kaempferol Triterpenoidsursolic acid The vast majority of phytonutrients presented in this chart have been studied for their antioxidant, anti-inflammatory, and anti-cancer properties, and in many cases the results have been impressive. Equally important in the cranberry research has been the finding that isolated phytonutrients in cranberry do not account for the same degree of health benefit as phytonutrients taken as a complete, synergistic group. What this research finding means is simple: it's the whole cranberry that supports our health best.
When speaking in general terms about the health benefits of cranberries, it is also important to know that the most commonly consumed form of this food is juice processed from the berries and typically produced by adding generous amounts of sugar. This form of cranberry cannot provide you with cranberry's full phytonutrient benefits. The cranberry "presscake"-or what is left behind in terms of skins and flesh after the juice has been processed out-typically contains the bulk of the phytonutrients when evaluated in lab studies.
Protection against Urinary Tract Infection (UTI)
Long before researchers started investigating from the standpoint of science, cranberry has been used to help prevent and treat urinary tract infections (UTIs). While the acidity of cranberries was at one time an important target of research, we now know that cranberry's ability to provide UTI benefits is not primarily related to its acidity, but rather to its proanthocyanidin (PAC) content. The PACs in cranberry have a special structure (called A-type linkages) that makes it more difficult for certain types of bacteria to latch on to our urinary tract linings. Include in these types of bacteria are pathogenic (infection-causing) strains of E. coli - one of the most common microorganisms involved in UTIs. By making it more difficult for unwanted bacteria like E. coli to cling onto the urinary tract linings, cranberry's PACs help prevent the expansion of bacterial populations that can result in outright infection. The age group in which researchers are least sure about this process involves children-it's just not clear when cranberry's health benefits fully extend to this age group. The area where benefits have been most pronounced are in middle-aged women who have experienced recurrent UTIs. In some studies, UTIs in this age and gender group have been reduced by more than one- third through dietary consumption of cranberry.
The discovery that cranberries prevent UTIs by blocking adhesion of bacteria to the urinary tract lining is a discovery that has allowed research on cranberry to expand out in other important directions. In our Digestive Benefits section below, we will describe how prevention of stomach ulcer is one very intriguing new direction in the cranberry research, based on this exact same principle of blocking bacterial adhesion to the lining of an organ system. (In the case of stomach ulcer, it's the stomach lining that's at risk, and the bacteria involved are the Helicobacter pylori bacteria.)
Anti-Inflammatory Benefits
For the cardiovascular system and for many parts of the digestive tract (including the mouth and gums, stomach, and colon) cranberry has been shown to provide important anti-inflammatory benefits. It's the phytonutrients in cranberry that are especially effective in lowering our risk of unwanted inflammation, and virtually all of the phytonutrient categories represented in cranberry are now known to play a role. These phytonutrient categories include proanthocyanidins (PACs), anthocyanins (the flavonoid pigments that give cranberries their amazing shades of red), flavonols like quercetin, and phenolic acid (like hydroxycinnamic acids).
In the case of our gums, the anti-inflammatory properties of cranberry can help us lower our risk of periodontal disease. Chronic, excessive levels of inflammation around our gums can damage the tissues that support our teeth. It's exactly this kind of inflammation that gets triggered by ongoing overproduction of certain cytokines. (Cytokines are messaging molecules, and the pro-inflammatory cytokines tell our cells to mount an inflammatory response. As messages are sent more frequently and more constantly, the inflammatory response becomes greater.) Phytonutrients in cranberry help reduce this inflammatory cascade of events precisely at the cytokine level. Production of pro-inflammatory cytokines like interleukin 6 (IL-6) and RANTES (Regulated on
Activation Normal T-cell Expressed and Secreted) is lowered by the activity of cranberry phytonutrients. In addition, cranberry phytonutrients inhibit the activity of the enzymes cyclo-oxygenase 1 (COX-1) and cyclo-oxygenase 2 (COX-2). These COX-1 and COX-2 enzymes are key factors in the production of other pro-inflammatory messaging molecules, and by inhibiting these enzymes, cranberry's phytonutrients significantly lower our risk of unwanted inflammation.
Dietary consumption of cranberry has also been shown to reduce the Rrisk of chronic, unwanted inflammation in the stomach, large intestine (colon) and cardiovascular system (especially blood vessel linings). We'll discuss some of these health benefits in more detail in the Digestive Benefits and Cardiovascular Benefits sections of this cranberry profile.
Mixed Findings for Kidney Stone Formation
Contrary to popular opinion, we believe that the latest research shows mixed results for cranberry with respect to kidney stone formation. This area of the health research can be confusing. Kidney stones can be formed from several different mineral-including combinations. The most common type of kidney stones formed in the United States involves a combination of calcium-plus-oxalic acid and are called calcium-oxalate stones. Among U.S. adults who develop kidney stones, about 75% develop calcium-oxalate stones. The other 25% develop a variety of different stones, including calcium-phosphate stones (called brushite stones), magnesium-sulfate containing stones (called struvite stones), and uric acid-containing stones (called urate stones). Since cranberries have the ability to increase the concentration of both calcium and oxalate in the urine, they can increase the likelihood of calcium-oxalate stone formation in susceptible individuals. Urinary uric acid, however, is typically decreased by intake of cranberry, and so risk of urate stones in susceptible individuals can be decreased by intake of cranberry. With other types of kidney stones, mixed effects of cranberry intake have been demonstrated. From our perspective, the bottom line at this point in the research process seems clear: individuals with kidney stone problems of any kind, or known susceptibility to kidney stone formation, should talk with their healthcare provider if considering inclusion of cranberry in their diet. Since 3 out of 4 U.S. adults experiencing kidney stone problems develop calcium-oxalate stones, there's a good chance for cranberry to be a problematic addition to the diet in the case of U.S. adults with a history of kidney stone formation.
Immune Support
While research in this area is somewhat limited, recent studies on the immune support benefits of cranberry are exciting. In studies on very small numbers of human participants, intake of cranberry extracts has shown the ability to improve multiple aspects of immune function, and to lower the frequency of cold and flu symptoms in the subjects. In several of these studies, the cranberry extracts were standardized to contain a known, higher-end amount of proanthocyanidins (PACs)-somewhat comparable to a double-strength cranberry juice. From our perspective, the doses of cranberry extract used in these studies match up fairly well with generous intake of whole, raw cranberries, and we look forward to future studies focused on precisely that: intake of whole, raw cranberries and resulting changes in cold and flu symptoms.
Cardiovascular Benefits
Following decreased risk of urinary tract infection (UTI), increased health of the cardiovascular system is perhaps the best-researched area of cranberry health benefits. It's the combined impact of cranberry antioxidants and anti-inflammatory phytonutrients in cranberry that's responsible here. Oxidative stress and chronic inflammation can place our blood vessel walls at great risk of damage. Once damaged, our blood vessels walls can undergo a process of plaque formation, and our risk of atherosclerosis (blood vessel wall thickening and blood vessel blocking) can be greatly increased. Dietary intake of cranberries and cranberry juice (in normal everyday amounts, unchanged for research study purposes) has been shown to prevent the triggering of two enyzmes that are pivotal in the atherosclerosis process (inducible nitric oxide synthase, or iNOS, and cyclo-oxygenase 2, or COX-2). In both cases, cranberry has also been shown to prevent activation of these enzymes by blocking activity of a pro-inflammatory cytokine- messaging molecule called tumor necrosis factor alpha (TNF-alpha). These anti-inflammatory benefits of cranberry appear to be critical components in the cardiovascular protection offered by this amazing fruit.
The antioxidant components of cranberries also appear to play a key role in cranberry's cardiovascular benefits. In animal studies, these antioxidant benefits have been clearly associated with decreased risk of high blood pressure. By reducing oxidative stress inside the blood vessels, cranberry extracts consumed by rats and mice have helped prevent overconstriction of the blood vessels and unwanted increases in blood pressure.
Three related phytonutrient compounds- resveratrol, piceatannol, and pterostilbene-deserve special mention with respect to cranberry's antioxidants. These unique phytonutrients may provide cranberry with some equally unique antioxidant properties, and a special ability to support our cardiovascular system in this regard.
A final area of cardiovascular support provided by cranberry is its ability to help us lower our LDL-cholesterol and total cholesterol, while simultaneously helping us increase our level of HDL-cholesterol. Cranberry most likely helps us achieve these cholesterol-improving changes by helping to improve oxidative and inflammatory aspects of the everyday environment in which our cholesterol-containing molecules must exist. This improved cholesterol control offered by cranberry contributes even further to our decreased risk of blood vessel blocking problems, since excess accumulation of LDL-cholesterol and insufficient amounts of HDL-cholesterol can increase the tendency of our blood vessels to become blocked. All in all, it's quite amazing how a simple food like cranberry can provide us with cardiovascular benefits at so many different levels, all rolled into one.
Antioxidant Protection
Although previously mentioned in this Health Benefits section, the antioxidants found in cranberry are especially important contributors to its potential for health support. From a research perspective, there are two especially important points to consider when thinking about the antioxidant benefits of cranberries. First is the amazing array of antioxidants that are found exclusively in whole cranberries. Cranberry's special combination of phenolic antioxidants, proanthocyanidin antioxidants, anthocyanin antioxidants, flavonoid antioxidants, and triterpenoid antioxidants is without a doubt unique. Also unique is the particular combination of three antioxidant nutrients-resveratrol, piceatannol, and pterostilbene-found in cranberry. Second are the research findings regarding the synergy between these nutrients. The phytonutrients in cranberry provide maximal antioxidant benefits only when consumed in combination with each other, and also only when consumed alongside of conventional antioxidant nutrients present in cranberry like manganese and vitamin C. When cranberry processing disrupts this antioxidant combination, health benefits from cranberry are decreased. Multiple studies in multiple health benefit areas point to this same conclusion-it's the overall blend of cranberry antioxidants that provides us with the strongest health benefits.
One further point about cranberry antioxidant research seems worthy of mention. In several research studies, cranberries were unable to provide significant antioxidant benefits when those benefits were measured in terms of blood values. In these studies, it took a much closer look at activities going on inside of our cells to demonstrate the antioxidant benefits of cranberries. The need to look inside of our cells to find cranberry antioxidant benefits may be telling us that the special value of cranberries may often involve metabolic events that are taking place "behind the scenes." In other words, these benefits may sometimes be missed in more broadly focused research studies, and cranberry may in fact have a stronger research track record than previously assumed.
Anti-Cancer Benefits
No area of cranberry research has been more intriguing in the past 10 years than research on cranberry and cancer, even though the majority of studies in this area have involved lab studies on human cancer cells or animal experiments. On a virtual year-by-year basis, scientists continue to identify new mechanisms that establish cranberries as anti-cancer agents. These mechanisms are now known to include: blocked expression of MMPs (matrix metalloproteinases); inhibition of ODC (ornithine decarboxylase enzymes); stimulation of QRs (quinone reductase enzymes); inhibition of CYP2C9s (Phase I detoxification enzymes); and triggering of apoptosis (programmed cell death) in tumor cells. It's important to point out that this amazing list of anti-cancer properties in cranberry is not sufficient to establish cranberry as a food to be used in the treatment of cancer. However, it is a list that appears consistent with other studies of cranberry and cancer showing dietary intake of this food to help prevent cancer occurrence. These cancer-preventive benefits of cranberry are especially likely in the case of breast, colon, lung, and prostate cancer.
None of the cancer-related benefits of cranberries should be surprising, since cranberry is loaded with antioxidant and anti-inflammatory nutrients. Chronic excessive oxidative stress (from lack of sufficient antioxidant support) and chronic excessive inflammation (from lack of sufficient anti-inflammatory compounds) are two key risk factors promoting increased likelihood of cancer. With its unique array of antioxidant and anti-inflammatory nutrients, cranberry seems ideally positioned to help us lower our risk of cancer development.
Digestive Tract Benefits
When you add up the health-related benefits of cranberry for our mouth and gums (decreased risk of periodontal disease), stomach (decreased risk of stomach ulcer), and colon (decreased risk of colon cancer), it's impossible not to conclude that cranberry is unique among fruits in its ability to provide us with digestive tract benefits. Every category of phytonutrient known to be provided by cranberry is also known to play a role in digestive tract support. In the case of cranberry's proanthocyanidins, it's decreased adherence of the bacterium Helicobacter pylori to our stomach wall that's made possible by intake of cranberry. In the case of cranberry's flavonoids, anthocyanins and triterpenoids, provide antioxidant and anti-inflammatory benefits that decrease our risk of colon cancer, and also our risk of periodontal disease.
Recent research has also shown that cranberry may be able to help optimize the balance of bacteria in our digestive tract. Participants in one recent study involving cranberry juice intake (in amounts of approximately 2 ounces per day and over the course of about 3 months) were able to increase the numbers of Bifidobacteria in their digestive tract while maintaining other bacterial types (Bifidobacteria are typically considered to be a desirable and "friendly" type of bacteria). As a result, the relative amount of Bifidobacteria was increased, and the bacterial environment of the digestive tract may have become more favorable. Given the vast array of phytonutrients in cranberry and the known connection between so many of these phytonutrients and digestive tract health, we expect to see the digestive benefits of cranberry becoming more and more apparent in future research on this incredible berry.
History
American Indians enjoyed cranberries cooked and sweetened with honey or maple syrup-a cranberry sauce recipe that was likely a treat at early New England Thanksgiving feasts. By the beginning of the 18th century, the tart red berries were already being exported to England by the colonists. Cranberries were also used by the Indians decoratively, as a source of red dye, and medicinally, as a poultice for wounds since not only do their astringent tannins contract tissues and help stop bleeding, but we now also know that compounds in cranberries have antibiotic effects.
Although several species of cranberries grow wild in Europe and Asia and have always been enjoyed in these part of the world, the cranberry most cultivated as a commercial crop is an American native, which owes its success to one Henry Hall, an observant gentleman in Dennis, Massachusetts. In 1840, Mr. Hall noticed an abundance of large berries grew when sand was swept into his bog by the prevailing winds and tides. The sandy bog provided just the right growing conditions for the cranberries by stifling the growth of shallow-rooted weeds, thus enhancing that of the deep rooted cranberries.
Cranberry cultivation soon spread not only across the U.S. through Wisconsin to Washington and Oregon, but also across the sea to Scandinavia and Great Britain. The hardy berries arrived in Holland as survivors of a shipwreck. When an American ship loaded with crates filled with cranberries sank along the Dutch coast, many crates washed ashore on the small island of Terschelling; some of the berries took root, and cranberries have been cultivated there ever since.
How to Select and Store
A fruit with a short season, fresh cranberries are harvested between Labor Day and Halloween and appear in markets from October through December.
Choose fresh, plump cranberries, deep red in color, and quite firm to the touch, lacking broken or mushy berries.
Firmness is a primary indicator of quality. In fact, during harvesting, high quality cranberries are often sorted from lesser quality fruits by bouncing the berries against barriers made of slanted boards. The best berries bounce over the barriers, while the inferior ones collect in the reject pile.
The deeper red their color, the more highly concentrated are cranberries' beneficial anthocyanin compounds. The Early Black cultivar (variety) of cranberry-with its particularly deep red color-has been found in one research study to have the highest concentration of anthocyanins.
Although typically packed in 12-ounce plastic bags, fresh cranberries, especially if organic, may be available in pint containers.
Fresh ripe cranberries can be stored in the refrigerator for up to 20 days. Before storing, discard any soft, discolored, pitted or shriveled fruits. When removed from the refrigerator, cranberries may look damp, but such moistness does not indicate spoilage, unless the berries are discolored or feel sticky, leathery or tough.
Once frozen, cranberries may be kept for several years. To freeze, spread fresh cranberries out on a cookie sheet and place in the freezer. In a couple of hours, the fully frozen berries will be ready to transfer to a freezer bag. Don't forget to date the bag before returning to the freezer.
Once thawed, frozen berries will be quite soft and should be used immediately.
Dried cranberries are sold in many groceries and may be found with other dried fruits.
How to Enjoy
Tips for preparing cranberries
While not as fragile as blueberries, fresh cranberries should be treated with care. Just prior to use, place cranberries in a strainer and briefly and gently rinse under cool running water.
When using frozen berries in recipes that do not require cooking, thaw well and drain prior to using. For cooked recipes, use unthawed berries since this will ensure maximum flavor. Extend the cooking time a few minutes to accommodate for the frozen berries. A
Healthiest Way of Preparing Cranberries
Cranberries retain their maximum amount of nutrients and their maximum taste when they are enjoyed fresh and not prepared in a cooked recipe. That is because their nutrients—:including vitamins, antioxidants, and enzymes- are unable to withstand the temperature (350̊F/175̊C) used in baking.
A few quick serving ideas
Individual Concerns
Cranberries and Oxalates
Cranberries are among a small number of foods that contain measurable amounts of oxalates, naturally -occurring substances found in plants, animals, and human beings. The relationship between cranberries and formation of kidney stones containing oxalates is not what you might expect, however. In the case of cranberries, the oxalate content is actually quite low, between 5-7 milligrams per 3.5 ounces. However despite their low oxalate content, cranberries are able to increase the amount of both oxalates and calcium in the urine, resulting in urine with increased concentrations of calcium oxalate. (The acidity of cranberries and other aspects of their chemical composition appear responsible for this impact on the urine.) Individuals at risk of calcium oxalate kidney stone formation will most likely want to avoid cranberries for the above reasons, and if considering inclusion of cranberries in their diet, should consult beforehand with a qualified healthcare provider. For some other, less common types of kidney stones - including struvite stones (containing magnesium sulfate) and brushite stones (one form of stones containing calcium phosphate), intake of cranberry juice may actually help lower a person's risk. As you can see, the relationship between cranberry juice and kidney stones can sometimes be confusing, and for this reason, if you are in doubt about this aspect of your health, we recommend a consult with your healthcare provider before making a decision about cranberries in your diet.
Cranberries and Warfarin
Warfarin is a prescription anticoagulant medication that has widely been used to help prevent formation of blood clots in individuals with a strong tendency toward clotting, and to help prevent future episodes in individuals who have already experienced formation of unwanted blood clots. Over the past ten years, there have been a small number of published case studies reporting cranberry juice-related problems by individuals taking warfarin. Despite the small number of cases, however, these reported problems have been quite serious, and in one circumstance, involved the death of an individual who was following his doctor's medical prescription for warfarin and while also consuming cranberry juice. The connection between cranberry juice and warfarin treatment has now been clearly shown to involve the detoxification enzyme family CYP2C9. The activity of this enzyme family is needed to break down warfarin so that its anticoagulant activity does not become excessive. (If CYP2C9 enzymes in the liver cannot successfully metabolize and neutralize warfarin, it can become too difficult for a person to stop an occurrence of bleeding.) Even though we now know that cranberry juice can inhibit CYP2C9 enzymes, researchers are still not clear about the risk posed by cranberries and cranberry juice for individuals who have been placed on a warfarin prescription. In lab studies, cranberry juice has repeatedly been shown to inhibit the breakdown of warfarin by CYP2C9 enzymes. However, in a recent study on health human volunteers who consumed three 8.5-ounce glasses of double-strength cranberry juice along with a single dose of warfarin, this inhibiting of CYP29C enzymes failed to occur. Overall, these research results seem somewhat confusing, and to err on the safe side, I encourage and recommend that all persons taking warfarin consult with their healthcare provider before incorporating cranberries or cranberry juice into the diet.
While familiar nutrients like vitamin C and fiber play a very important role in cranberry's health benefits, it's the amazing array of phytonutrients in cranberries that has gotten the special attention of health researchers. There are at least 5 key categories of health-supportive phytonutrients in cranberries, as summarized in the following chart:
Cranberry Phytonutrients
Type of PhytonutrientSpecific Molecules Phenolic Acidshydroxybenzoic acids including vanillic acids; hydroxycinnamic acids inculding caffeic, coumaric, cinnamic, and ferulic acids Proanthocyanidinsepicatechins Anthocyaninscyanidins, malvidins, and peonidins Flavonoidsquercetin, myricetin, kaempferol Triterpenoidsursolic acid The vast majority of phytonutrients presented in this chart have been studied for their antioxidant, anti-inflammatory, and anti-cancer properties, and in many cases the results have been impressive. Equally important in the cranberry research has been the finding that isolated phytonutrients in cranberry do not account for the same degree of health benefit as phytonutrients taken as a complete, synergistic group. What this research finding means is simple: it's the whole cranberry that supports our health best.
When speaking in general terms about the health benefits of cranberries, it is also important to know that the most commonly consumed form of this food is juice processed from the berries and typically produced by adding generous amounts of sugar. This form of cranberry cannot provide you with cranberry's full phytonutrient benefits. The cranberry "presscake"-or what is left behind in terms of skins and flesh after the juice has been processed out-typically contains the bulk of the phytonutrients when evaluated in lab studies.
Protection against Urinary Tract Infection (UTI)
Long before researchers started investigating from the standpoint of science, cranberry has been used to help prevent and treat urinary tract infections (UTIs). While the acidity of cranberries was at one time an important target of research, we now know that cranberry's ability to provide UTI benefits is not primarily related to its acidity, but rather to its proanthocyanidin (PAC) content. The PACs in cranberry have a special structure (called A-type linkages) that makes it more difficult for certain types of bacteria to latch on to our urinary tract linings. Include in these types of bacteria are pathogenic (infection-causing) strains of E. coli - one of the most common microorganisms involved in UTIs. By making it more difficult for unwanted bacteria like E. coli to cling onto the urinary tract linings, cranberry's PACs help prevent the expansion of bacterial populations that can result in outright infection. The age group in which researchers are least sure about this process involves children-it's just not clear when cranberry's health benefits fully extend to this age group. The area where benefits have been most pronounced are in middle-aged women who have experienced recurrent UTIs. In some studies, UTIs in this age and gender group have been reduced by more than one- third through dietary consumption of cranberry.
The discovery that cranberries prevent UTIs by blocking adhesion of bacteria to the urinary tract lining is a discovery that has allowed research on cranberry to expand out in other important directions. In our Digestive Benefits section below, we will describe how prevention of stomach ulcer is one very intriguing new direction in the cranberry research, based on this exact same principle of blocking bacterial adhesion to the lining of an organ system. (In the case of stomach ulcer, it's the stomach lining that's at risk, and the bacteria involved are the Helicobacter pylori bacteria.)
Anti-Inflammatory Benefits
For the cardiovascular system and for many parts of the digestive tract (including the mouth and gums, stomach, and colon) cranberry has been shown to provide important anti-inflammatory benefits. It's the phytonutrients in cranberry that are especially effective in lowering our risk of unwanted inflammation, and virtually all of the phytonutrient categories represented in cranberry are now known to play a role. These phytonutrient categories include proanthocyanidins (PACs), anthocyanins (the flavonoid pigments that give cranberries their amazing shades of red), flavonols like quercetin, and phenolic acid (like hydroxycinnamic acids).
In the case of our gums, the anti-inflammatory properties of cranberry can help us lower our risk of periodontal disease. Chronic, excessive levels of inflammation around our gums can damage the tissues that support our teeth. It's exactly this kind of inflammation that gets triggered by ongoing overproduction of certain cytokines. (Cytokines are messaging molecules, and the pro-inflammatory cytokines tell our cells to mount an inflammatory response. As messages are sent more frequently and more constantly, the inflammatory response becomes greater.) Phytonutrients in cranberry help reduce this inflammatory cascade of events precisely at the cytokine level. Production of pro-inflammatory cytokines like interleukin 6 (IL-6) and RANTES (Regulated on
Activation Normal T-cell Expressed and Secreted) is lowered by the activity of cranberry phytonutrients. In addition, cranberry phytonutrients inhibit the activity of the enzymes cyclo-oxygenase 1 (COX-1) and cyclo-oxygenase 2 (COX-2). These COX-1 and COX-2 enzymes are key factors in the production of other pro-inflammatory messaging molecules, and by inhibiting these enzymes, cranberry's phytonutrients significantly lower our risk of unwanted inflammation.
Dietary consumption of cranberry has also been shown to reduce the Rrisk of chronic, unwanted inflammation in the stomach, large intestine (colon) and cardiovascular system (especially blood vessel linings). We'll discuss some of these health benefits in more detail in the Digestive Benefits and Cardiovascular Benefits sections of this cranberry profile.
Mixed Findings for Kidney Stone Formation
Contrary to popular opinion, we believe that the latest research shows mixed results for cranberry with respect to kidney stone formation. This area of the health research can be confusing. Kidney stones can be formed from several different mineral-including combinations. The most common type of kidney stones formed in the United States involves a combination of calcium-plus-oxalic acid and are called calcium-oxalate stones. Among U.S. adults who develop kidney stones, about 75% develop calcium-oxalate stones. The other 25% develop a variety of different stones, including calcium-phosphate stones (called brushite stones), magnesium-sulfate containing stones (called struvite stones), and uric acid-containing stones (called urate stones). Since cranberries have the ability to increase the concentration of both calcium and oxalate in the urine, they can increase the likelihood of calcium-oxalate stone formation in susceptible individuals. Urinary uric acid, however, is typically decreased by intake of cranberry, and so risk of urate stones in susceptible individuals can be decreased by intake of cranberry. With other types of kidney stones, mixed effects of cranberry intake have been demonstrated. From our perspective, the bottom line at this point in the research process seems clear: individuals with kidney stone problems of any kind, or known susceptibility to kidney stone formation, should talk with their healthcare provider if considering inclusion of cranberry in their diet. Since 3 out of 4 U.S. adults experiencing kidney stone problems develop calcium-oxalate stones, there's a good chance for cranberry to be a problematic addition to the diet in the case of U.S. adults with a history of kidney stone formation.
Immune Support
While research in this area is somewhat limited, recent studies on the immune support benefits of cranberry are exciting. In studies on very small numbers of human participants, intake of cranberry extracts has shown the ability to improve multiple aspects of immune function, and to lower the frequency of cold and flu symptoms in the subjects. In several of these studies, the cranberry extracts were standardized to contain a known, higher-end amount of proanthocyanidins (PACs)-somewhat comparable to a double-strength cranberry juice. From our perspective, the doses of cranberry extract used in these studies match up fairly well with generous intake of whole, raw cranberries, and we look forward to future studies focused on precisely that: intake of whole, raw cranberries and resulting changes in cold and flu symptoms.
Cardiovascular Benefits
Following decreased risk of urinary tract infection (UTI), increased health of the cardiovascular system is perhaps the best-researched area of cranberry health benefits. It's the combined impact of cranberry antioxidants and anti-inflammatory phytonutrients in cranberry that's responsible here. Oxidative stress and chronic inflammation can place our blood vessel walls at great risk of damage. Once damaged, our blood vessels walls can undergo a process of plaque formation, and our risk of atherosclerosis (blood vessel wall thickening and blood vessel blocking) can be greatly increased. Dietary intake of cranberries and cranberry juice (in normal everyday amounts, unchanged for research study purposes) has been shown to prevent the triggering of two enyzmes that are pivotal in the atherosclerosis process (inducible nitric oxide synthase, or iNOS, and cyclo-oxygenase 2, or COX-2). In both cases, cranberry has also been shown to prevent activation of these enzymes by blocking activity of a pro-inflammatory cytokine- messaging molecule called tumor necrosis factor alpha (TNF-alpha). These anti-inflammatory benefits of cranberry appear to be critical components in the cardiovascular protection offered by this amazing fruit.
The antioxidant components of cranberries also appear to play a key role in cranberry's cardiovascular benefits. In animal studies, these antioxidant benefits have been clearly associated with decreased risk of high blood pressure. By reducing oxidative stress inside the blood vessels, cranberry extracts consumed by rats and mice have helped prevent overconstriction of the blood vessels and unwanted increases in blood pressure.
Three related phytonutrient compounds- resveratrol, piceatannol, and pterostilbene-deserve special mention with respect to cranberry's antioxidants. These unique phytonutrients may provide cranberry with some equally unique antioxidant properties, and a special ability to support our cardiovascular system in this regard.
A final area of cardiovascular support provided by cranberry is its ability to help us lower our LDL-cholesterol and total cholesterol, while simultaneously helping us increase our level of HDL-cholesterol. Cranberry most likely helps us achieve these cholesterol-improving changes by helping to improve oxidative and inflammatory aspects of the everyday environment in which our cholesterol-containing molecules must exist. This improved cholesterol control offered by cranberry contributes even further to our decreased risk of blood vessel blocking problems, since excess accumulation of LDL-cholesterol and insufficient amounts of HDL-cholesterol can increase the tendency of our blood vessels to become blocked. All in all, it's quite amazing how a simple food like cranberry can provide us with cardiovascular benefits at so many different levels, all rolled into one.
Antioxidant Protection
Although previously mentioned in this Health Benefits section, the antioxidants found in cranberry are especially important contributors to its potential for health support. From a research perspective, there are two especially important points to consider when thinking about the antioxidant benefits of cranberries. First is the amazing array of antioxidants that are found exclusively in whole cranberries. Cranberry's special combination of phenolic antioxidants, proanthocyanidin antioxidants, anthocyanin antioxidants, flavonoid antioxidants, and triterpenoid antioxidants is without a doubt unique. Also unique is the particular combination of three antioxidant nutrients-resveratrol, piceatannol, and pterostilbene-found in cranberry. Second are the research findings regarding the synergy between these nutrients. The phytonutrients in cranberry provide maximal antioxidant benefits only when consumed in combination with each other, and also only when consumed alongside of conventional antioxidant nutrients present in cranberry like manganese and vitamin C. When cranberry processing disrupts this antioxidant combination, health benefits from cranberry are decreased. Multiple studies in multiple health benefit areas point to this same conclusion-it's the overall blend of cranberry antioxidants that provides us with the strongest health benefits.
One further point about cranberry antioxidant research seems worthy of mention. In several research studies, cranberries were unable to provide significant antioxidant benefits when those benefits were measured in terms of blood values. In these studies, it took a much closer look at activities going on inside of our cells to demonstrate the antioxidant benefits of cranberries. The need to look inside of our cells to find cranberry antioxidant benefits may be telling us that the special value of cranberries may often involve metabolic events that are taking place "behind the scenes." In other words, these benefits may sometimes be missed in more broadly focused research studies, and cranberry may in fact have a stronger research track record than previously assumed.
Anti-Cancer Benefits
No area of cranberry research has been more intriguing in the past 10 years than research on cranberry and cancer, even though the majority of studies in this area have involved lab studies on human cancer cells or animal experiments. On a virtual year-by-year basis, scientists continue to identify new mechanisms that establish cranberries as anti-cancer agents. These mechanisms are now known to include: blocked expression of MMPs (matrix metalloproteinases); inhibition of ODC (ornithine decarboxylase enzymes); stimulation of QRs (quinone reductase enzymes); inhibition of CYP2C9s (Phase I detoxification enzymes); and triggering of apoptosis (programmed cell death) in tumor cells. It's important to point out that this amazing list of anti-cancer properties in cranberry is not sufficient to establish cranberry as a food to be used in the treatment of cancer. However, it is a list that appears consistent with other studies of cranberry and cancer showing dietary intake of this food to help prevent cancer occurrence. These cancer-preventive benefits of cranberry are especially likely in the case of breast, colon, lung, and prostate cancer.
None of the cancer-related benefits of cranberries should be surprising, since cranberry is loaded with antioxidant and anti-inflammatory nutrients. Chronic excessive oxidative stress (from lack of sufficient antioxidant support) and chronic excessive inflammation (from lack of sufficient anti-inflammatory compounds) are two key risk factors promoting increased likelihood of cancer. With its unique array of antioxidant and anti-inflammatory nutrients, cranberry seems ideally positioned to help us lower our risk of cancer development.
Digestive Tract Benefits
When you add up the health-related benefits of cranberry for our mouth and gums (decreased risk of periodontal disease), stomach (decreased risk of stomach ulcer), and colon (decreased risk of colon cancer), it's impossible not to conclude that cranberry is unique among fruits in its ability to provide us with digestive tract benefits. Every category of phytonutrient known to be provided by cranberry is also known to play a role in digestive tract support. In the case of cranberry's proanthocyanidins, it's decreased adherence of the bacterium Helicobacter pylori to our stomach wall that's made possible by intake of cranberry. In the case of cranberry's flavonoids, anthocyanins and triterpenoids, provide antioxidant and anti-inflammatory benefits that decrease our risk of colon cancer, and also our risk of periodontal disease.
Recent research has also shown that cranberry may be able to help optimize the balance of bacteria in our digestive tract. Participants in one recent study involving cranberry juice intake (in amounts of approximately 2 ounces per day and over the course of about 3 months) were able to increase the numbers of Bifidobacteria in their digestive tract while maintaining other bacterial types (Bifidobacteria are typically considered to be a desirable and "friendly" type of bacteria). As a result, the relative amount of Bifidobacteria was increased, and the bacterial environment of the digestive tract may have become more favorable. Given the vast array of phytonutrients in cranberry and the known connection between so many of these phytonutrients and digestive tract health, we expect to see the digestive benefits of cranberry becoming more and more apparent in future research on this incredible berry.
History
American Indians enjoyed cranberries cooked and sweetened with honey or maple syrup-a cranberry sauce recipe that was likely a treat at early New England Thanksgiving feasts. By the beginning of the 18th century, the tart red berries were already being exported to England by the colonists. Cranberries were also used by the Indians decoratively, as a source of red dye, and medicinally, as a poultice for wounds since not only do their astringent tannins contract tissues and help stop bleeding, but we now also know that compounds in cranberries have antibiotic effects.
Although several species of cranberries grow wild in Europe and Asia and have always been enjoyed in these part of the world, the cranberry most cultivated as a commercial crop is an American native, which owes its success to one Henry Hall, an observant gentleman in Dennis, Massachusetts. In 1840, Mr. Hall noticed an abundance of large berries grew when sand was swept into his bog by the prevailing winds and tides. The sandy bog provided just the right growing conditions for the cranberries by stifling the growth of shallow-rooted weeds, thus enhancing that of the deep rooted cranberries.
Cranberry cultivation soon spread not only across the U.S. through Wisconsin to Washington and Oregon, but also across the sea to Scandinavia and Great Britain. The hardy berries arrived in Holland as survivors of a shipwreck. When an American ship loaded with crates filled with cranberries sank along the Dutch coast, many crates washed ashore on the small island of Terschelling; some of the berries took root, and cranberries have been cultivated there ever since.
How to Select and Store
A fruit with a short season, fresh cranberries are harvested between Labor Day and Halloween and appear in markets from October through December.
Choose fresh, plump cranberries, deep red in color, and quite firm to the touch, lacking broken or mushy berries.
Firmness is a primary indicator of quality. In fact, during harvesting, high quality cranberries are often sorted from lesser quality fruits by bouncing the berries against barriers made of slanted boards. The best berries bounce over the barriers, while the inferior ones collect in the reject pile.
The deeper red their color, the more highly concentrated are cranberries' beneficial anthocyanin compounds. The Early Black cultivar (variety) of cranberry-with its particularly deep red color-has been found in one research study to have the highest concentration of anthocyanins.
Although typically packed in 12-ounce plastic bags, fresh cranberries, especially if organic, may be available in pint containers.
Fresh ripe cranberries can be stored in the refrigerator for up to 20 days. Before storing, discard any soft, discolored, pitted or shriveled fruits. When removed from the refrigerator, cranberries may look damp, but such moistness does not indicate spoilage, unless the berries are discolored or feel sticky, leathery or tough.
Once frozen, cranberries may be kept for several years. To freeze, spread fresh cranberries out on a cookie sheet and place in the freezer. In a couple of hours, the fully frozen berries will be ready to transfer to a freezer bag. Don't forget to date the bag before returning to the freezer.
Once thawed, frozen berries will be quite soft and should be used immediately.
Dried cranberries are sold in many groceries and may be found with other dried fruits.
How to Enjoy
Tips for preparing cranberries
While not as fragile as blueberries, fresh cranberries should be treated with care. Just prior to use, place cranberries in a strainer and briefly and gently rinse under cool running water.
When using frozen berries in recipes that do not require cooking, thaw well and drain prior to using. For cooked recipes, use unthawed berries since this will ensure maximum flavor. Extend the cooking time a few minutes to accommodate for the frozen berries. A
Healthiest Way of Preparing Cranberries
Cranberries retain their maximum amount of nutrients and their maximum taste when they are enjoyed fresh and not prepared in a cooked recipe. That is because their nutrients—:including vitamins, antioxidants, and enzymes- are unable to withstand the temperature (350̊F/175̊C) used in baking.
A few quick serving ideas
- Take advantage of cranberries' tartness by using them to replace vinegar or lemon when dressing your green salads. Toss the greens with a little olive oil and then add color and zest with a handful of raw cranberries.
- To balance their extreme tartness, combine fresh cranberries with other fruits such as oranges, apples, pineapple or pears. If desired, add a little fruit juice, honey or maple syrup to chopped fresh cranberries.
- For an easy-to-make salad that will immediately become a holiday favorite, place 2 cups fresh berries in your blender along with ½ cup of pineapple chunks, a quartered skinned orange, a sweet apple (such as one of the Delicious variety) and a handful or two of walnuts or pecans. Blend till well mixed but still chunky. Transfer to a large bowl.
- Dice 3-4 stalks of celery, add to the cranberry mixture and stir till just combined.
- Combine unsweetened cranberry in equal parts with your favorite fruit juice and sparkling mineral water for a lightly sweetened, refreshing spritzer. For even more color appeal, garnish with a slice of lime.
- Add color and variety to your favorite recipes for rice pudding, quick breads or muffins by using dried cranberries instead of raisins.
- Sprinkle a handful of dried cranberries over a bowl of hot oatmeal, barley, or any cold cereal.
- Mix dried cranberries with lightly roasted and salted nuts for a delicious snack.
Individual Concerns
Cranberries and Oxalates
Cranberries are among a small number of foods that contain measurable amounts of oxalates, naturally -occurring substances found in plants, animals, and human beings. The relationship between cranberries and formation of kidney stones containing oxalates is not what you might expect, however. In the case of cranberries, the oxalate content is actually quite low, between 5-7 milligrams per 3.5 ounces. However despite their low oxalate content, cranberries are able to increase the amount of both oxalates and calcium in the urine, resulting in urine with increased concentrations of calcium oxalate. (The acidity of cranberries and other aspects of their chemical composition appear responsible for this impact on the urine.) Individuals at risk of calcium oxalate kidney stone formation will most likely want to avoid cranberries for the above reasons, and if considering inclusion of cranberries in their diet, should consult beforehand with a qualified healthcare provider. For some other, less common types of kidney stones - including struvite stones (containing magnesium sulfate) and brushite stones (one form of stones containing calcium phosphate), intake of cranberry juice may actually help lower a person's risk. As you can see, the relationship between cranberry juice and kidney stones can sometimes be confusing, and for this reason, if you are in doubt about this aspect of your health, we recommend a consult with your healthcare provider before making a decision about cranberries in your diet.
Cranberries and Warfarin
Warfarin is a prescription anticoagulant medication that has widely been used to help prevent formation of blood clots in individuals with a strong tendency toward clotting, and to help prevent future episodes in individuals who have already experienced formation of unwanted blood clots. Over the past ten years, there have been a small number of published case studies reporting cranberry juice-related problems by individuals taking warfarin. Despite the small number of cases, however, these reported problems have been quite serious, and in one circumstance, involved the death of an individual who was following his doctor's medical prescription for warfarin and while also consuming cranberry juice. The connection between cranberry juice and warfarin treatment has now been clearly shown to involve the detoxification enzyme family CYP2C9. The activity of this enzyme family is needed to break down warfarin so that its anticoagulant activity does not become excessive. (If CYP2C9 enzymes in the liver cannot successfully metabolize and neutralize warfarin, it can become too difficult for a person to stop an occurrence of bleeding.) Even though we now know that cranberry juice can inhibit CYP2C9 enzymes, researchers are still not clear about the risk posed by cranberries and cranberry juice for individuals who have been placed on a warfarin prescription. In lab studies, cranberry juice has repeatedly been shown to inhibit the breakdown of warfarin by CYP2C9 enzymes. However, in a recent study on health human volunteers who consumed three 8.5-ounce glasses of double-strength cranberry juice along with a single dose of warfarin, this inhibiting of CYP29C enzymes failed to occur. Overall, these research results seem somewhat confusing, and to err on the safe side, I encourage and recommend that all persons taking warfarin consult with their healthcare provider before incorporating cranberries or cranberry juice into the diet.
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