Cranberries

Health benefits

Outstanding phytonutrient benefits from cranberries

While cranberries have gotten less attention than other family members in the Ericaceae plant family (for example, blueberries), they more than earn their credentials as phytonutrient-rich foods. Over two dozen health-supportive phytonutrients have been identified in cranberries, with proanthocyanidins and anthocyanins leading the way. These two groups of phytonutrients are interrelated. Proanthocyanidins are larger molecules from which anthocyanins can be made. But they also have health-supportive properties of their own. It is not uncommon to find 150–350 milligrams of proanthocyanidins per fresh cup of cranberries and 15–170 milligrams of anthocyanins. The presence of these phytonutrient groups in cranberries makes itself known to our senses, because both groups help to provide cranberries with their vibrant red color.

The list below summarizes some of the spotlight phytonutrients provided to us by cranberries. Most of the phytonutrients below have been shown to have antioxidant and/or anti-inflammatory properties, in addition to other health benefits.

• Anthocyanins
  • cyanidins
  • delphinidins
  • malvidins
  • pelargonidins
  • peonidins
  • petunidins
• Flavan-3-ols
  • catechins
  • epicatechins
• Flavonols
  • isorhamnetin
  • kaempferol
  • myricetin
  • quercetin
• Hydroxybenzoic acids
  • o-hydroxybenzoic acid
  • p-hydroxybenzoic acid
• Hydroxycinnamic acids
  • caffeic acid
  • coumaric acid
  • ferulic acid
  • sinapic acid
• Proanthocyanidins
  • procyanidins
  • propelargonidins
  • prodelphinidins
• Stilbenoids
  • resveratrol
• Tannins
  • ellagitannins
• Terpenoids
  • ursolic acid
  • hydroxycinnamoyl ursolic acid

Cardiovascular benefits from cranberries

Two unwanted conditions in our cardiovascular system—the presence of oxidative stress and the presence of chronic inflammation—are risk factors for a variety of chronic cardiovascular diseases. In this context, it should not be surprising to find cranberries providing us with cardiovascular benefits since these berries are a concentrated source of both antioxidant and anti-inflammatory phytonutrients. (Cranberries are also a very good source of vitamin C and a good source of vitamin E, two important antioxidant nutrients. And in addition, they are a very good source of the mineral manganese, which is needed for proper function of some forms of the enzyme superoxide dismutase.)

Multiple studies have shown the ability of cranberry consumption to raise the total antioxidant capacity in our bloodstream. For the most part, these studies have involved intake of cranberry juice in amounts of approximately 2–3 cups per day over a period of 2–4 weeks. Similar levels of cranberry juice intake have been shown to decrease blood levels of total cholesterol and triglycerides. In addition, levels of two apolipoproteins (called ApoA and ApoB) have been shown to change following consumption of cranberry juice. (The term “lipoprotein” may be more familiar than many people realize. The letter “L” in the term “LDL cholesterol” and “HDL cholesterol” stands for “lipoprotein.” The term “apolipoprotein” refers to are structural component of many lipoproteins that helps them to function properly.) Cranberry juice intake has been shown to decrease levels of ApoB and increase levels of ApoA-1. These changes are the exact ones needed to lower our risk of several cardiovascular diseases including atherosclerosis.

The cardiovascular benefits of cranberry consumption have also been demonstrated in research participants previously diagnosed with Metabolic Syndrome (MetS). MetS is not considered a chronic disease but rather a key risk factor for many chronic diseases—including multiple diseases of the cardiovascular system. Consumption of approximately 2 cups of cranberry juice per day over a period of 8–12 weeks improved virtually all cardiovascular lab results (including the lab results listed above).

Other potential health benefits from cranberries

Considering their very good fiber content, very low sugar content (in fresh form), and their concentration of antioxidant and anti-inflammatory phytonutrients, cranberries might be expected to provide us with health benefits in the area of blood sugar regulation. In general, research studies support this conclusion, although there are a few extenuating factors that prompt us to summarize this area of cranberry research as providing evidence of “potential health benefits.” One of these factors is the lack of large-scale human studies. Most of the research that we have reviewed on cranberries and blood sugar has involved rats and mice in a lab setting. However, improved insulin and blood sugar regulation has been a fairly reliable finding in these animal studies. We’ve also seen a cranberry study on persons diagnosed with Metabolic Syndrome (MetS) in which consumption of cranberry juice resulted in lower fasting blood glucose levels. However, what we have not seen is a large-scale study on healthy persons whose risk of blood sugar problems was determined to lower as a result of cranberry intake.

A second factor that partially clouds the research on cranberries and blood sugar regulation is the form in which most U.S. consumers enjoy cranberries—namely, in the form of sweetened juice. It’s not uncommon for a commercial cranberry juice to contain 25–30 grams of added sugar per 8 ounces. In addition, dried cranberries are typically sweetened and commonly contain about 8 grams of sugar per tablespoon. Since U.S. consumers overwhelmingly choose these sugar-added forms of cranberries, it can be difficult to separate out the blood sugar benefits of cranberries alone versus these cranberries-plus-sugar combinations.

Since urinary tract infection (UTI) is an individual clinical condition, it falls outside of the research that we do on overall healthy eating. But it is difficult to overlook this condition with respect to cranberries, because for many people, it is one of the first conditions that comes to mind when thinking about cranberries (and especially cranberry juice). While some studies show clear benefits of cranberry intake for UTI, we decided to place this information about cranberry and UTI in our “Potential Health Benefits” section for two reasons.

First, the overall research in this area has shown mixed results. For example, in many less complicated occurrences of UTI, E. coli bacteria serve as the source of the infection, and these bacteria are less able to adhere to cell linings in the urinary tract due to presence of proanthocyanins from cranberry. However, E. coli is not always a primary cause in UTI, and even when E.coli is involved, its involvement may be complicated by many other factors.

Second, while cranberry phytonutrients—including triterpenoids like ursolic acid—are able to decrease activity in inflammatory pathways, these anti-inflammatory properties may be more helpful in some instances of UTI than in others due to the varied circumstances of UTI. In addition, when we evaluate studies on the anti-inflammatory properties of foods, we always like to see studies on the whole foods themselves and these studies are largely missing from the research on UTI and cranberries. Most cranberry-UTI studies have used capsules of cranberry powder, cranberry extract, or cranberry juice rather than whole cranberries. For all of these reasons, we consider the cranberry-UTI research to show potential health benefits on a case-by-case type basis rather than across-the-board benefits. Before leaving the topic of cranberry-UTI, it is also worth noting that the limited number of studies showing positive results with the use of cranberry juice and fresh berries have generally utilized 1–2 cups of juice or berries per day over the course of 1–12 months.

Description

Unlike many of the foods that we profile on our website, cranberries are native to North America and have never become widely naturalized to other parts of the world. In fact, over 80% of all cranberries grown worldwide are grown in the U.S. and Canada. (And roughly twice as many cranberries are grown in the U.S. compared to Canada.) For U.S. consumers, cranberries are an indigenous food that has unique ties to this region of the world.

Among our WHF, cranberries are most closely related to blueberries. Both of these berries belong to the Ericaceae family of plants, as well as to the Vaccinium genus. When you compare the phytonutrient richness of these two berries, you will also find a good bit of overlap. But we think it is safe to say that cranberries are unique in many ways, and one of these ways involves the manner in which they grow.

Because of pictures taken during harvest season, some people may think that cranberries are grown in water (versus soil). But this description is not correct. Cranberries are grown on very low-lying vines that thrive on a special combination of peat-based sandy soil and wet conditions. The habitat in which cranberries grow is usually referred to as a “bog” or “marsh.” Grassy marshes, forested swamps, peat bogs, and other types of wetland habitats are natural growing places for cranberries. Some cranberry bogs were formed naturally over very long periods of time; others have many man-made elements. When cranberries are produced commercially, the cranberry bogs usually account for a small percent of the acreage needed to grow the cranberries. Surrounding the bogs are watersheds and reservoirs needed to sustain productivity in the bogs. In addition, piping systems are set up to assist with commercial production.

Cranberries generally take about 16 months to fully mature. They are typically planted in late spring, summer, or early fall of year 1, winter over in dormant form, and then resume growth during the spring of year 2. They typically reach maturity in the fall of this second year. Commercial cranberry growers usually flood their bogs twice over the course of their growth cycle. A first flooding occurs at the start of winter. This flooding is used to protect the dormant cranberry vines during the winter months. Once winter has ended, the cranberry bogs are drained and the cranberries continue to grow until early fall. When harvest time arrives, the bogs are flooded for a second time since it is easier to harvest the cranberries once they have floated up to the top of the water. If you see pictures of cranberries bogs during times of flooding, it is easy to assume that they are growing in the water!

We often get asked about the benefits of white versus red cranberries. White cranberries are simply red cranberries that were harvested on the early side, before forming the anthocyanins and proanthocyanidins that give them their vibrant red color. “Early” in this case may involve a very short period of time, usually involving only 2–4 weeks. Given the documented health benefits of phytonutrients like anthocyanins and proanthocyanidins, you might wonder how white cranberries could still make a good food choice. The answer to this question lies in the difference in taste between white and red cranberries. The earlier-harvested white version is milder in overall taste and less tart than the red version that has been harvested at full maturity. If this taste difference holds the key to inclusion of cranberries in your meal plan, it makes sense to enjoy the earlier-harvested white version. For maximum anthocyanin and proanthocyanidin content, fully mature red cranberries are preferable. Fruits, fruit juices, honey, and other ingredients can balance their tartness in recipes.

The color of red cranberries can vary from bright red to pale red to scarlet to deep crimson to purple. White cranberries are not typically sheer white in color but more greenish white or yellowish white. They can also be soft yellow or even more distinctly yellow in tone. If they have been harvested at a time when their anthocyanins and proanthocyanidins have started to form, they can also take on an overall yellow tone with different-sized areas of red blush.

The cranberries we purchase in the supermarket all belong to the same genus and species of plant, that of Vaccinium macrocarpon. (You might also see the designation, Vaccinium macrocarpon Aiton, where “Aiton” refers to the name of the taxonomy authority involved with this naming.) On a non-commercial basis, however, you can find several additional species of cranberries, including Vaccinium oxycoccos, which is sometimes referred to as “small cranberry” due to its smaller leaves and berries.

History

As a food native to North America, cranberries have traditionally been enjoyed by many native peoples throughout what is now the United States and Canada. Cranberries were originally given different names in various tribal languages, including the name “ibimi”—which meant bitter/sour berries—in Wampanoag and Lenni Lenape. The name “cranberry” came from much later observations by European colonizers of North America that the flowers of cranberry plants were shaped like the head and neck of sandhill cranes, which lead to the term “craneberry.” The word “craneberry” was eventually shortened to “cranberry.”

As the world’s largest single producer of cranberries, the United States has a well-documented history of cranberry production. The key cranberry-producing states of Wisconsin (by far the largest producer) and Massachusetts (easily landing in second place) combined in 2016 to produce over 8 million barrels of cranberries. Approximately 1 million additional barrels were produced by the states of New Jersey, Oregon, and Washington. Cranberry production in the U.S. has a rich family history and a high degree of continuity in comparison to many other areas of agricultural production. For example, cranberry marshes developed in the late 1800’s and early 1900’s around Manitowish Waters and Eagle River in Wisconsin remain productive to this day. In addition, some of the cranberry vines that currently produce cranberries are more than 100 years in age.

A surprisingly large number of cranberry varieties are grown within the U.S. (The total number of varieties is upward of 100.) These varieties are typically highly adapted to specific regions of the country and climate conditions. Examples of cranberry varieties include Ben Lear, Black Veil, Centerville, Champion, Gebhardt, Howes, McFarlin, Paradise, Potters, Pride, Searles, and Wales Henry.

It’s worth noting how few cranberries are actually grown for fresh consumption. Only 5% of U.S. cranberries are sold fresh. The remaining 95% are sold for processing, mostly into cranberry juice, but also into dried, sweetened cranberries, and cranberry sauce.

On a worldwide basis, no country comes close to producing the number of cranberries as the United States, with the possible exception of Canada. In 2014, about 840 million pounds of cranberries were produced in the U.S., and about 388 million pounds were produced in Canada. Chile produced about 180 million pounds and a handful of other countries produced 10% or less of this Chilean amount. These additional countries included Belarus, Azerbaiijan, Latvia, and Romania.

How to select and store

Fresh cranberries are harvested in the fall, usually between mid-September and mid-November, and particularly during the month of October. For the freshest picked cranberries, this season is best.

Choose fresh, plump cranberries that are quite firm to the touch. Firmness is a primary indicator of quality.

The anthocyanin and proanthocyanidin phytonutrient content of cranberries increases as they become more richly red in color. Their red shades can vary from bright red to deep crimson to near purple. While all cranberries will provide you with phytonutrient richness, if you are wanting to maximize your intake of anthocyanins and proanthocyanidins, you’ll want select cranberries with these richly red colors.

Many U.S. consumers have become accustomed to finding fresh berries in loose form in their local supermarket, usually in half-pint, pint, or quart containers. For example, blueberries, raspberries, and strawberries are often sold in this way. Yet, you may or may not find this type of packaging for fresh cranberries in your local supermarket. Sometimes the only fresh cranberries that you will find have been pre-bagged in plastic. For example fresh cranberries pre-bagged in 12-ounce weights are often available.

Certified organically grown cranberries are recommended. Repeated research studies on organic foods as a group show that exposure to contaminants such as pesticides and heavy metals can be greatly reduced through the purchase of certified organic produce, including cranberries. In many cases, you may be able to find a local organic grower who sells cranberries but has not applied for formal organic certification either through the U.S. Department of Agriculture (USDA) or through a state agency. (Examples of states offering state-certified organic foods include California, New York, Oregon, Vermont, and Washington.) However, if you are shopping in a large supermarket, your most reliable source of organically grown cranberries is very likely to be cranberries that display the USDA organic logo.

Fresh ripe cranberries can be stored in the refrigerator for approximately 3 weeks. Before storing, discard any soft, discolored, pitted or shriveled fruits. When removed from the refrigerator, cranberries may look damp, but such moistness does not automatically indicate spoilage, unless the berries are discolored or feel sticky, leathery or tough. However, if any of these conditions is present, we recommend that you err on the safe side and avoid consuming the berries.

Fresh cranberries should remain refrigerated until they are consumed. Refrigeration will help preserve their overall quality as well as their vitamin C content.

Once frozen, cranberries will keep for 6–12 months. . To freeze cranberries, spread them out on a cookie sheet and place them 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 it to the freezer.

Once thawed, frozen berries will be quite soft and should be used immediately.

When selecting cranberries, many people wonder about the pros and cons of purchasing dried cranberries. On the “pro” side, dried cranberries are highly convenient to handle and store and can provide some of the nutrient benefits available from fresh cranberries. They also typically retain some of the distinctly delightful cranberry taste. On the “con” side, commercially dried cranberries can sometimes be difficult to find except in pre-sweetened form, and they can undergo significant nutrient losses during processing.

Here are some details to show you how selecting presweetened dried cranberries can pose nutritional challenges. In terms of calories, the content for 100 grams of fresh cranberries is approximately 45–50 calories while for the same amount of dried sweetened cranberries, the calorie content is approximately 300 calories. In terms of vitamin C content, 100 grams of fresh cranberries typically features between 10-15 milligrams of this nutrient while with dried sweetened cranberries this vitamin C content may decrease to 1 milligram or less.

As a very general rule, if you are seeking to get a little bit of that unique cranberry flavor but aren’t considering the purchase of fresh cranberries, we recommend keeping your intake of presweetened, dried cranberries to a small but flavor-enhancing amount: in the range of 1–2 teaspoons. It is also important to add, however, that some specialty producers sell unsweetened dried cranberries to which other ingredients have not been added. Many people enjoy these unsweetened dried versions “as is,” while others prefer to use them when baking or in the preparation of sauces and other recipes.

Tips for preparing and cooking

Preparation

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.

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, antioxidant compounds, and enzymes) are unable to withstand the temperature (350°F/175°C) used in baking.

How to enjoy

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 1/2 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 unsweetened cranberries instead of raisins.
• Sprinkle a handful of dried unsweetened cranberries over a bowl of hot oatmeal, barley, or any cold cereal.
• Mix dried unsweetened cranberries with lightly roasted and salted nuts for a delicious snack.

Recipes that feature cranberries

• Perfect Oatmeal
• Cranberry Sauce
• Holiday Cranberry Relish

Nutritional profile

One cup (100g) at 46 calories provides vitamin C (18% DV), fiber (16% DV), manganese (16% DV). Smaller but measurable amounts of vitamin E (8% DV), copper (7% DV), pantothenic acid (6% DV), vitamin K (6% DV) round out the profile. Cranberry provides us with an astonishing array of phytonutrients. Included among these phytonutrients are proanthocyanidins and anthocyanins; flavan-3-ols like catechins and epicatechins; flavonols like isorhamnetin, kaempferol, myricetin, and quercetin; and terpenoids like ursolic acid. Many of these phytonutrients offer antioxidant and anti-inflammatory benefits.

What’s new and beneficial about cranberries

• For many years, researchers believed that the ability of cranberries and cranberry juice to help prevent urinary tract infections (UTIs) was partly related to the strong acidity of the cranberries. Recent research has shown that it’s not the acidity of the cranberries, but the unusual nature of their proanthocyanidins (PACs) that is related to prevention of UTIs. The special structure of these PACs (involving A-type linkages between their components) acts as a barrier to bacteria that might otherwise latch on to the urinary tract lining. In many studies, the UTI-preventing benefits of cranberries are somewhat modest and limited to women who have recurrent UTIs. But this whole area of investigation has opened the door to an understanding of other possible cranberry benefits. For example, stomach ulcers are often related to overgrowth and over-linking of one particular type of stomach bacteria (Helicobacter pylori) to the stomach lining. In much the same way as cranberries may help prevent bacterial attachment to the lining of the urinary tract, they may also help prevent attachment of bacteria to the stomach lining. There is already some preliminary evidence that cranberry may help protect us from stomach ulcer in this way. We expect to see future studies confirming this fascinating type of health benefit.
• Many cranberries are water-harvested. Water-harvesting means that the cranberries are grown in bogs and floated in water to allow for easy harvesting. For many years, water-harvesting of cranberries has been looked upon as an industry convenience. It’s simply easier to harvest berries that are floating on the surface. However, recent research has shown that the anthocyanin content of cranberries (the phytonutrients that give the berries their amazing red color) is increased in direct proportion to the amount of natural sunlight striking the berry. If berries floating on top of water get exposed to increased amounts of natural sunlight (in comparison to other growing and harvesting conditions), they are likely to develop greater concentrations of anthocyanins. These greater concentrations of anthocyanins are likely to provide us with stronger health benefits. In other words, water-harvesting may turn out to provide more than just harvest convenience. If it can expose cranberries to greater amounts of natural sunlight, it can increase phytonutrient health benefits that involve the unique antioxidant and anti-inflammatory properties of anthocyanins.
• A substantial number of recent studies have shown that whole cranberries consumed in dietary form—in comparison with purified cranberry extracts consumed in either liquid or dried supplement form—do a better job of protecting our cardiovascular system and our liver. Several groups of researchers have summarized their health benefit findings by pointing out that it is the synergy among cranberry nutrients (rather than individual cranberry components) that is responsible for cranberry’s health benefits. This synergy is only found in the whole berry as consumed in food form. This rule about whole dietary intake appears to apply to the antioxidant benefits, anti-inflammatory benefits, and anti-cancer benefits of cranberry.
• Over the past 5 years, scientists have identified an increasing number of mechanisms that help explain the anti-cancer properties of cranberries. 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. The cancer-preventive benefits of cranberries are now known to extend to cancers of the breast, colon, lung, and prostate.

Recommendations

In our Healthiest Way of Eating Plan, we encourage the consumption of 5-10 servings of fruits-plus-vegetables (combined) eat day. We believe that the balance between fruits and vegetables can vary from day to day, depending upon personal health factors, personal taste preferences, and optimal combining of foods in recipes as well as meals. We recognize that our recommendation calls for a more generous amount of fruits and vegetables than the amount recommended by the Centers for Disease Control (CDC) at the U.S. Department of Health and Human Services (DHHS). The CDC recommends between 1.5-2.5 cups of fruit and 2.5-4.0 cups of vegetables per day, as well as a target goal of at least 5 fruit-plus-vegetable servings (combined) per day. With respect to berries, the CDC approach provides the example of strawberries, and explains that 8 large strawberries count as 1 cup. If all fruit for the day were to be obtained from strawberries, the CDC recommendation would translate into 12-20 strawberries for the day as a way of meeting a requirement for 1.5-2.5 cups of fruit. We recommend that you set your fruit goals higher than these CDC amounts. Based on the scientific research, we believe it’s going to take closer to 3 fruit servings per day to provide you with optimum health benefits. With respect to berries in particular, we recommend that you include berries at least 3-4 times per week within your fruit servings. In several of our sample meal plans, we include berries on a daily basis! It would definitely not be a mistake for you to include a serving of berries in your daily meal plan! At the same time, we recognize that the fruit group contains many outstanding fruit options, and personal preferences (as well as local and seasonal availability) can vary greatly. Also, remember that large strawberries—at about 18 grams per berry and 8 berries per cup—stand at one end of the berry range in terms of size and recommended amount. Most berries are considerably smaller in size and weight, and a one-cup serving allows you to eat a lot more berries! With blueberries, for example, the average weight per berry is closer to 1-2 grams, and a cup’s worth of blueberries means about 100-150 berries. For cranberries and raspberries, the amount would be similar.

Among the fruits and vegetables richest in health-promoting antioxidants berries such as cranberries rank right up there at the top of the list. Antioxidants are essential to optimizing health by helping to combat the free radicals that can damage cellular structures as well as DNA. Provided that you do not experience any digestive difficulty, we recommend enjoying cranberries raw because they provide you with the best flavor and the greatest benefits from their vast array of nutrients, and may also offer the benefit of digestion-aiding enzymes. When you think about the flavors, nutrients, and enzyme content of raw fruit, it is no surprise that for thousands of years both in Asia and along the Mediterranean, people have been eating raw fruit for dessert, not only as a delicious and nutritious ending to a meal but also as a potential digestive aid. For more on the Nutrient-Rich Way of Preparing Cranberries, see the How to Enjoy section below.

Cranberries, fresh, whole
1.00 cup
(100.00 grams)

Calories: 46
GI: low

NutrientDRI/DV

 manganese18%

 vitamin C18%

 fiber18%

 vitamin E8%

 copper7%

 vitamin K6%

 pantothenic acid6%

Food Rating System Chart

• Health Benefits
• Description
• History
• How to Select and Store
• Tips for Preparing and Cooking
• How to Enjoy
• Individual Concerns
• Nutritional Profile
• References

Individual concerns

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, all persons taking warfarin should consult with their healthcare provider before incorporating cranberries or cranberry juice into the diet.