Encyclopedia of Health Benefits of Berries

 Cranberries
  9. Cranberries:


These are white when unripe and turn red on ripening. They are used to make juices, sauces, wines, etc. There are many cranberry health benefits that have been recently discovered. They contain moderate levels of vitamin C, dietary fiber, minerals, and manganese.

Cranberries are a superfood that you should enjoy all year round.

Cranberries have vitamin C and fiber, and are only 45 calories per cup. In disease-fighting antioxidants, cranberries outrank nearly every fruit and vegetable--including strawberries, spinach, broccoli, red grapes, apples, raspberries, and cherries.

One cup of whole cranberries has 8,983 total antioxidant capacity. Only blueberries can top that: Wild varieties have 13,427; cultivated blueberries have 9,019.

While they are available frozen year-round, in fall and winter you can buy cranberries fresh. Fresh cranberries stored in a tightly-sealed plastic bag in the refrigerator will last up to two months. But be careful: If one starts to get soft and decay, the others will, too--so remove soft ones before you store them. Cooked cranberries can last up to a month in a covered container in the fridge.

Here are a few ideas for getting these antioxidant powerhouses into your life:

  • Add dried cranberries to your favorite cereal

  • Drink 100% fruit juice that includes cranberries

  • Sneak cranberries into blueberry muffins for added color and flavor

  • Pair cranberries with chicken and pork dishes

Cranberries are among the top foods with proven health benefits, according to Amy Howell, a researcher at Rutgers University. Cranberries are full of antioxidants, which protects cells from damage by unstable molecules called free radicals.
The National Institutes of Health is funding research on the cranberry’s effects on heart disease, yeast infections and other conditions, and other researchers are investigating its potential against cancer, stroke and viral infections.

So far, research has found:

Drinking cranberry juice can block urinary infections by binding to bacteria so they can’t adhere to cell walls. While women often drink unsweetened cranberry juice to treat an infection, there’s no hard evidence that works. A compound Howell discovered in cranberries, proanthocyanidine, prevents plaque formation on teeth; mouthwashes containing it are being developed to prevent periodontal disease.

In some people, regular cranberry juice consumption for months can kill the H. pylori bacteria, which can cause stomach cancer and ulcers. Preliminary research also shows:

Drinking cranberry juice daily may increase levels of HDL, or good cholesterol and reduce levels of LDL, or bad cholesterol. Cranberries may prevent tumors from growing rapidly or starting in the first place. Extracts of chemicals in cranberries prevent breast cancer cells from multiplying in a test tube; whether that would work in women is unknown.

Health Benefits of Cranberry

CranberriesWhile 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 Phytonutrient Specific Molecules
Phenolic Acids hydroxybenzoic acids including vanillic acids; hydroxycinnamic acids inculding caffeic, coumaric, cinnamic, and ferulic acids
Proanthocyanidins epicatechins
Anthocyanins cyanidins, malvidins, and peonidins
Flavonoids quercetin, myricetin, kaempferol
Triterpenoids ursolic 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.
 


 

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Dated 12 March 2013