Berries, Choice Fruit, and Good Health
Berries, Choice Fruit, and Good Health
By Francis Brinker, ND. Dr. Brinker is Clinical Assistant Professor, Department of Medicine, College of Medicine, University of Arizona; he is author of Complex HerbsComplete Medicines and other books and is a retained consultant for Eclectic Institute, Inc.
The United States Department of Agriculture (USDA) Dietary Guidelines for Americans 2005 states: "Compared with the many people who consume a dietary pattern with only small amounts of fruits and vegetables, those who eat more generous amounts as part of a healthful diet are likely to have reduced risk of chronic diseases, including stroke and perhaps other cardiovascular diseases, type 2 diabetes, and cancers in certain sites [oral cavity and pharynx, larynx, lung, esophagus, stomach, and colon-rectum]. Diets rich in foods containing fiber, such as fruits, ... may reduce the risk of coronary heart disease."1
Key USDA recommendations include: "Two cups of fruit and two and a half cups of vegetables per day are recommended for a reference 2,000-calorie intake. Choose a variety of fruits and vegetables each day." Using half-cup serving sizes, this average intake amounts to 9 servings of fruits and vegetable daily. For children the amount of fruit recommended is 2-3 servings daily. "Consumption of whole fruits (fresh, frozen, canned, dried) rather than fruit juice for the majority of the total daily amount is suggested to ensure adequate fiber intake."1 According to the USDA Pyramid, 100% fruit juices count as part of the fruit group, which includes berries.2
The American Heart Association Diet and Lifestyle Recommendations Revision 2006 and the American Cancer Society echo the USDA and offer these practical tips:3,4
- Eat fruits without high-calorie sauces or added salt and sugars;
- Replace high-calorie foods with fruits;
- Encourage the consumption of whole fruits in place of juices;
- Include a variety of fruits, especially those deeply colored throughout, like berries; and
- Focus on techniques that preserve nutrient and fiber content without additives.
These recommendations reflect a growing consensus that daily consumption of fruit is essential in a plan to help reduce the risk of succumbing to some of America's worst illnesses. A simple question arises. On what scientific basis are these recommendations being made?
Whole Foods
Whenever a nutrient is found by scientific research to be beneficial in preventing some health problem, the public is invariably urged to consume food that is high in that component rather than simply taking it in pill form as an isolated compound. This is certainly good advice as regards nutrients for disease prevention, though high doses of isolated nutrients are sometimes optimal for exaggerated individual nutrient requirements or extreme deficiency symptoms. The corollary to whole food consumption for optimal nutrition would be the use of whole herbs or native botanical extracts in preference to purified derivative drugs when the botanicals are therapeutically sufficient. Regarding the prevention of chronic degenerative diseases, even conventional doctors advocate the superiority of food sources compared to supplementing single nutrients considered essential due to physiological necessity, e.g., vitamins and minerals.
Now there is a growing awareness in the medical community about the importance of "secondary" plant metabolites.5 These bioactive phytochemicals are part of the design of nature and biological processes necessary for optimal function and so can help maintain and prolong good health.
These chemicals exist in plants in complex combinations that are known to be complementary, additive, and/or synergistic in their physiological effects. Phytochemicals have distinctive effects, many of which are based on a particular polyphenolic molecular structure.6
Pigments
Along with chlorophyll and carotenes, polyphenols are largely responsible for the various colors that distinguish foods from plants. In the fruit category the red, blue, and deep purple anthocyanin pigments (cyanos is Greek for blue) are typically found in greatest concentrations and diversity in berries. The most commonly consumed berries in the Western diet tend to be from the genera Vaccinium (e.g., cranberry, blueberry, bilberry, and lingonberry or huckleberry) and Rubus (e.g., blackberry, black raspberry, red raspberry, boysenberry, cloudberry, loganberry, and marionberry).6
The anthocyanin and other phenolic compounds found in berries vary from species to species and even within different cultivars of a species, but often a species will share many of the same components with other berry species of the same genus. For example, in addition to similar anthocyanins, the Vaccinium species contain common proanthocyanidins whereas Rubus species contain predominantly ellagitannins. All of these polyphenols serve functionally as antioxidants.6-8
Other flavonoids such as flavonols and flavones are often yellow, as their name implies (flavus is Latin for yellow), and found extensively in both fruit and vegetables. The flavonols myricetin, quercetin, and quercetin glycosides are particularly abundant in Vaccinium species, whereas quercetin glycosides are predominant in Rubus species.9,10
These flavonoids are greatly reduced during processing, as shown with total quercetin and kaempferol contents in fresh Vaccinium (cranberries, blueberries) and Rubus (blackberries, raspberries) versus their jams.11 Likewise, on a dry weight basis, fresh fruit such as cranberries and grapes contain a much greater total polyphenol content than dried fruit. Still, the dried fruit provides greater antioxidant activity than isolated vitamins C, E, or beta-carotene.12
Antioxidant Activity and Phenolic Content of Fruit
One common effect of consuming fruit and vegetables containing the polyphenolic phytochemicals that has been recognized by clinical studies is their ability to prevent cellular oxidative damage. The outcomes of this activity are far-ranging when the impact on chronic degenerative diseases is considered. For example, in a 16-year prospective study of almost 35,000 postmenopausal women-years, the consumption of total flavonoids of different classes was found to correlate with reduced risk of cardiovascular disease (CVD). After multivariate adjustment an inverse association was observed between consumption of anthocyanidins and coronary heart disease, CVD, and total mortality, and between flavones and total mortality. Specific foods associated with a reduced mortality from CVD include strawberries, apples, pears, red wine, and chocolate.13
Flavonoids co-exist as complex mixtures in plants that act together as hydrogen-donating antioxidants, even protecting vitamins C and E from oxidation in foods and in the gastrointestinal (GI) tract. Gallic acid and the majority of flavonoids including anthocyanins have more antioxidant activity than these two vitamins. They also chelate metals such as iron and copper, thereby preventing free radical generation catalyzed by these ions.5 Each type of polyphenolic compound provides distinctive qualities, while each specific compound within these phytochemical categories has its own unique effect.8 The benefits of consuming whole berries can be vastly expanded by using different kinds of berries together, especially those from different genera.6
The absolute amount by percentage of dry weight of all antioxidant components (including polyphenols, carotenoids, glutathione, and vitamins C and E) in the American diet is greatest among culinary herbs and spices. However, based on typical serving sizes and in order of rank, the five richest sources of these compounds are blackberries, walnuts, strawberries, artichokes, and cranberries, while raspberries, blueberries, and grape juice are also included in the top 10.14
A preferred means of measuring antioxidant activity is the oxygen radical absorbance capacity (ORAC) that can be applied both to protection of either fat-based (lipo-philic) or water-based (hydrophilic) substances. The hydrophilic ORAC values for most plant foods is much greater than for lipophilic antioxidant activity. The fresh fruit with the highest hydrophilic ORAC per serving are the blueberry, cranberry, blackberry, strawberry, raspberry, red delicious apple, sweet cherry, and black plum.15
Reducing Risks of Cancer and CVD
Since consumption of fruits and their antioxidant compounds have been associated with a reduced risk of chronic diseases like CVD,13 one of the high hopes held for increasing antioxidant consumption is lowering the risk of developing cancer. An integrated series of case-control studies between 1983 and 1990 in northern Italy investigated more than 8,000 cases of different types of cancer and compared fruit and vegetable consumption with more than 6,000 controls admitted to the hospital for non-cancerous acute conditions. Multivariate relative risks were derived to account for normal differences in backgrounds and behaviors. There was a consistent pattern of protection with vegetable consumption for all epithelial cancers (urinary tract, reproductive organs, and the digestive tract and its organs except the gall bladder), while for fruit a strong inverse relationship was found with cancers of the upper digestive and respiratory tracts (mouth, throat, larynx, and esophagus). Also, significant inverse relationships were found with fruit consumption and cancers of the liver, pancreas, prostate, and urinary tract.16
When a meta-analysis of 15 case-control studies and one cohort study considered the impact of consumption of plant products on oral cancer, it was shown for fruit that each portion consumed per day significantly reduced the risk by 49%, and vegetables similarly reduced the overall risk by 50%.17 A review of the epidemiological literature on the cancer preventive effects of human consumption of fruits and vegetables found limited evidence for cancers of the mouth, pharynx, esophagus, stomach, colon/rectum, larynx, lung, kidney, bladder (fruit only), and ovary (vegetables only). Based on the range of prevalence of low fruit and vegetable intake, a crude estimate of the percentage of preventable cancers in those with low intake is in the range of 5-12%.19
Fruit appears beneficial in animal studies through their ability to counteract, reduce, and repair damage due to inflammation and oxidative stress. In addition to polyphenols, other phytochemicals in berries that may contribute to their anticancer potential include stilbenoids like resveratrol, lignans like secoisolariciresinol, and triterpenoids like ursolic acid. Based on in vitro studies, complexes of these components in various berry products may also impact enzymes that metabolize carcinogens and help regulate transcription and growth factors and signalling pathways of cancer proliferation, tumor angiogenesis, and apoptosis. The sensitization of tumor cells to chemotherapy drugs is another means by which berry fruit may even be of benefit in the treatment of some cancers.19
In a study beginning in the late 1990s with a Japanese population of 77,891 men and women 45-74 years of age, a validated food frequency questionnaire was used to evaluate the association of fruit and vegetable consumption with the risk of total cancer and cardiovascular disease. By the end of 2002, the data showed no association of fruit or vegetable intake with a decreased risk of total cancer, but consumption of fruit significantly lowered the risk of cardiovascular disease.20
Prospective cohort studies with 75,596 women ages 34-59 years with 14 years of follow up and 38,683 men ages 40-75 years with eight years of follow up looked at the risk of ischemic stroke in the context of fruit and vegetable intake. All were free of cardiovascular disease, diabetes, and cancer at baseline. Those persons in the highest quintile of fruit and vegetable intake who had a median of 5.1 and 5.8 servings daily among the men and women, respectively, had a relative risk of 0.69 compared to the lowest quintile. Each increment of one serving daily was associated with a 6% lower risk of ischemic stroke.21
Brain Neurological Protection
The risk of dementia or Alzheimer's disease was assessed in 8,085 non-demented subjects older than 65 years of age in a three-city cohort study in France from 1999 to 2000 and re-examined over four years with a follow-up rate of 89%. In fully adjusted models, the daily consumption of fruits and vegetables was associated with a decreased risk of all-cause dementia.22 Age-related neurodegenerative diseases like Alzheimer's or Parkinson's disease are superimposed on motor and cognitive behavioral deficits that appear to be a normal aspect of aging. Reducing the diminishment of neuronal function is important to enhance health while aging. Antioxidant and anti-inflammatory polyphenolics found in berries offer a good potential antidote to the behavioral manifestations associated with senescence. They provide a nontoxic means of neuroprotection by reducing oxidative stress and inhibiting the inflammatory mediators like COX-1 and COX-2.23
Flavonoids, in particular the anthocyanins of berries and dark-skinned grapes, function as potent antioxidant, anti-inflammatory, and anti-aging agents, as shown by their ability to prevent cognitive and motor changes associated with aging in rats.23
Specific Examples of Antioxidant-rich Berries and Fruit
To illustrate the potency of "ordinary" fruit typically consumed without much thought for their high antioxidant phytochemical content, two common American berries representative of the familiar Vaccinium and Rubus genera are described, as well as one of the prized produce from the Old World. The variety of compounds available from these few fruit help illustrate how the different families, genera, and species contribute their own unique value, so that each expands and enhances nature's rich cornucopia.
Cranberry (Vaccinium macrocarpon), Ericaceae family
Drinking cranberry juice has long been associated with lowering the risk of urinary tract infections (UTIs). Daily consumption of 300 mL of the juice high in organic acids such as quinic, malic, and citric acids reduced the amount of bacteria and white blood cells in the urine significantly after two months. However, besides added sweetener, cranberry juice has lost some of the nutritional content in the berries.24
A 2002 case-control study comparing 139 pairs of women with acute UTIs to those who had none in the prior five years showed that consumption of fresh fruit or berry juice was associated with a lower risk of UTI occurrence. A preference of berry juice including cranberry over other fruit juices for lowering the risk was attributed to their high flavonoid content.25 UTIs are much more prevalent in women than men, such that about 50% of women will have one or more UTIs in their lifetime. This helps account for more than 7 million physician office visits for this condition each year.26
Cranberry products have been effective for preventing UTIs in forms ranging from the liquid cranberry juice to the juice cocktail or from spray-dried juice to cranberry tablets. Proanthocyanidins in cranberry products prevent adhesion of pathogenic Escherichia coli to the mucosa of the urinary tract. It is the proanthocyanidins in cranberry that are primarily credited with helping prevent UTIs, since the organic acids fail to lower urinary pH as previously believed.26 The proanthocyanidin content of raw berries is much greater than in the juice or juice cocktail. Procyanidins, a subclass of proanthocyanidins, are a mixture of linked catechin and epicatechin units. In cranberry, these consist largely of epicatechin and, unlike most other procyanidins in food, are linked via A-type bonds that are responsible for the unique anti-adhesion action.27
When 12 women who had six UTIs in the previous year were given cranberry extract capsules twice daily for 12 weeks to provide about 100 mg per day of total proanthocyanidins, none developed a UTI during that time (when 24 UTIs would have been expected). Eight continued with various cranberry products for two years with no recurrences of UTIs, while four stopped taking cranberry supplements. Of those who stopped, two developed symptoms that resolved with resumption of cranberry products, and one had a UTI treated with antibiotics but resumed cranberry use and had no further symptoms.28
The potential benefits of cranberry do not end in the urinary tract. The anti-adhesion effect has been shown also to inhibit Helicobacter pylori, the bacteria responsible for most gastric and duodenal ulcers and potentially GI cancer, from attaching to human mucosal cells. A cranberry fraction also inhibits adhesion of Streptococci and Actinomyces to tooth surfaces and so may help prevent cavities. However, these findings are limited to in vitro research and have not been confirmed in human studies.26,27 An advantage of using cranberry powder is avoiding the intake of sugar added to the juice cocktail.
Likewise, the in vitro antioxidant activity of the anthocyanins (glycosides of cyanidin and peonidin) in cranberry along with its flavonols (quercetin, myricetin), flavan-3-ols (proanthocyanidins, epicatechin), phenolic acids (benzoic, coumaric, sinapic, caffeic, and ellagic acids), and stilbene (resveratrol) holds promise for helping lower the risk of CVD. This was shown in animal studies by reducing low-density lipoprotein (LDL) oxidation ex vivo and lowering LDL levels in vivo.29,30 Cranberries are also high in antioxidant carotenes, especially when fresh, as compared by weight to the dried sweetened berries or the juice or juice cocktail.27
In spite of diminished antioxidant content, consumption of cranberry juice in human studies using increasing amounts of 125, 250, and 500 mL/d over three 4-week periods led to a reduction in LDL and increase in high-density lipoprotein (HDL).27 In 30 healthy men (mean age 51 years) on the same dosage schedule, oxidized LDL, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 were all significantly decreased.29 However, another study that gave 750 mL/d of cranberry juice for only two weeks to 20 healthy women of ages 18-40 years found no changes in LDL, HDL, or plasma antioxidant potential.30
Cardiovascular health is further promoted by reduced platelet aggregation and vasodilation, as shown in animals given cranberry juice. Contrary to case reports of cranberry juice inhibiting S-warfarin metabolism, human studies have found it has no effect on S-warfarin metabolic enzymes CYP2C9 or CYP3A.27
Consumption of cranberry juice has resulted in the elevation of urinary salicylate concentrations in women who were not using aspirin or other salicylate drugs. After taking 750 mL/d for one week, salicylic acid and its metabolite, salicyluric acid, were markedly elevated in the urine, and after two weeks salicylic acid was significantly increased in the plasma. The anti-inflammatory effects of this compound may be associated in part with lowering the risk of colon cancer following consumption of fruit and vegetables.31 Also, along with grapes and other Vaccinium species, cranberry is relatively high in the antioxidant stilbene compound resveratrol that has been shown to possess cancer chemopreventive properties in vitro.32
The antiproliferative effect against human cancer cell lines was investigated for a total cranberry extract rich in organic acids (30.0%), total polyphenols (10.6%), proanthocyanidins (5.5%), and anthocyanins (1.2%). The total extract was compared with the separated fractions for activity against human oral, colon, and prostate cancer cell lines in vitro. The most active against all cell lines was the total polyphenolic fraction.33 Though exposure of colon and prostate cells in vivo to all of the components of the total extract or its fractions is improbable, oral tissue has immediate exposure to the complete components.
The same can be said of the esophagus. Esophageal adenocarcinoma rates, and its precursor, Barrett's esophagus, have increased rapidly over the past several decades. A proanthocyanidin-rich extract of cranberries was tested against human esophageal adenocarcinoma cells in vitro. The extract induced cell cycle arrest at G1 and resulted in significant apoptosis.34
Blackberry (Rubus fruticosus), Rosaceae family
Though there have not been as many clinical studies on blackberries as on cranberries, there has been useful preclinical research on this fruit and some of its major components. It is no surprise that blackberries are a rich source of polyphenolic anthocyanin pigments. Since the berries are only available fresh while in season, various means of preserving their active compounds were studied (quick-frozen, canned in water or syrup, pureed, juiced, and clarified and/or pasteurized juice). Based upon ORAC and photochemiluminescence assays, after processing and after one, three, and six months of storage, individually quick-frozen berries or juice had the least loss of antioxidant capacity and monomeric anthocyanins after one day. Most processing led to losses of antioxidant capacity and up to 65% of monomeric anthocyanins, while increasing polymeric color values up to 7%.35
Ellagitannins are another major class of bioactive polyphenols in blackberries. The main ellagitannin in Rubus species is commonly referred to as peduncu-lagin.36 As a source of ellagic acid, blackberries rank first with raspberries ahead of 19 other freeze-dried fruit and five nuts. The others with high ellagic acid content in decreasing order were strawberries, walnuts, pecans, and cranberries. However, the ellagic acid content of juice from raspberries and strawberries was negligible. Its importance is that ellagic acid is known to inhibit carcinogenesis in animals.37
Rats fed ellagic acid had significant increases in liver glutathione S-transferase (GST) activity and GST-Ya mRNA content. This specific increase in detoxification potential can reduce carcinogen-induced mutagenesis and tumorigenesis.38 Similarly, feeding rats 400 mg ellagic acid per kg of diet-induced NAD(P)H:quinone reductase, another detoxifying phase II enzyme.42
In addition, ellagic acid at 10-5 M blocks mitosis of cervical carcinoma cells in vitro by G1 arrest after 48 hours and induces apoptosis in these cells and inhibits overall cell growth after 72 hours.40 Furthermore, ellagic acid has been found to interact with quercetin and resveratrol in a synergistic manner to induce apoptosis and reduce cell growth in human leukemia cells, which involved the induction of caspase 3 activity.41
Besides containing large amounts of anthocyanins and ellagic acid, freeze-dried blackberries, washed and frozen within 2-4 hours of picking, yield significant amounts of vitamins A, C, and E, potassium, and phytosterols.42
Grapes (Vitis vinifera), Vitaceae family
The use of grapes parallels the story of Western civilization. Ancient tales and hieroglyphics indicate that they were consumed fresh, dried as raisins, or juiced and fermented for preservation as wine. As foods, beverages, and medicines, grapes, raisins, and wines have been consumed down through the ages from the Egyptians to the Greeks, Romans, Western Europeans, and Americans. Even the pomace, formed by the skins and seeds after the juice is pressed out, is utilized for its phytochemical content. The skins of grapes, especially when dark colored, are high in resveratrol and glucosides of quercetin, kaempferol, and myricetin. Anthocyanin pigments in dark grape skins include glucosides of delphinidin, petunidin, malvidin, and/or cyanidin and peonidin. The seeds are high in procyanidins, including both oligomers (OPCs) or polymers (condensed tannins) of catechin and epicatechin that are also present in the skin in smaller amounts.43
Small amounts of these components that are extracted with the juice to make red wines provide most of the health value of these alcoholic beverages. The recent interest in consuming red wine for lowering the risk of coronary heart disease (CHD) is associated with the "French paradox" of reduced CHD mortality in France compared to other industrialized countries. However, even the consumption of nonalcoholic purple grape juice for 14 days by 15 adults with coronary artery disease resulted in improved flow-mediated vasodilation and reduced LDL susceptibility to oxidation.44
The repeated consumption of red wine (200 mL once daily) for six weeks led to sustained increase in total phenolic compounds in the plasma but no increase in plasma antioxidant capacity.45 Moderate red wine consumption (375 mL daily containing about 165 mg of flavonols, procyanins, and anthocyanidins) for two weeks not only increased total plasma phenolic concentrations, including catechin and epicatechin glucuronides, but oxidized LDL was reduced and HDL cholesterol concentrations were likewise increased. This serves to help verify the "French paradox": In spite of elevated dietary fat intake, serum cholesterol, and systolic blood pressure, consumption of phenolic compounds in red wine help reduce CHD risk beyond the effects of alcohol alone.46
Research on phenolics isolated from grapes show that de-alcoholized red wine, resveratrol, and the flavonol quercetin all demonstrate dose-dependent inhibition of platelet aggregation in vitro, whereas other components had no effect. Resveratrol and de-alcoholized red wine high in this stilbene also inhibited in vitro lipoxygenase formation of eicosanoid inflammatory mediators: thromboxane B2 (dose-dependently) and to a lesser extent 12-HETE. Quercetin and de-alcoholized red wine low in resveratrol only inhibited 12-HETE synthesis.47 Resveratrol is metabolized by CYP1A2 to yield piceatannol,48 as well as by CYP1B1 that is high in tumors.49 While resveratrol is a potential cancer preventive agent,50 piceatannol has known anticancer activity.49 Resveratrol may help prevent carcinogen activation by its inhibition of CYP as shown in liver cells in vitro.51
A study with 20 healthy subjects gave 300 mL red wine or white wine to 10 each for 15 days. A urinary marker of oxidative stress and plasma levels of polyphenols (catechin, caffeic acid, resveratrol) were measured. Those taking red wine had significantly higher plasma polyphenol levels compared with the white wine group. The plasma polyphenols were inversely correlated with the urine content of the oxidative stress marker. The concentration range of red wine polyphenols found in the plasma was also shown to inhibit LDL oxidation in vitro.52
Besides consuming alcohol daily, another concern about red wine involves interactions with drugs. A 250 mL amount was shown to increase plasma cisapride levels in 12 men, presumably by inhibiting CYP3A4, but by only 15% compared to a 51% increase from grapefruit juice inhibition of this enzyme.53 However, a crossover study with six men and six women taking 360 mL of red wine or water actually resulted in decreased bioavailability of the CYP3A4 substrate cyclosporine with red wine. This is probably due to its decreased absorption resulting from the lower solubility of cyclosporine in wine than water.54
Of the total extractable phenolics in grapes, about 10% or less are in the pulp, 28-35% in the skin, and 60-70% in the seeds. Grape seeds contain 5-8% polyphenols, depending on the variety. They are mostly flavonoids, including the monomeric epicatechin, catechin, gallocatechin, epigallocatechin, and epicatechin gallate, as well as gallic acid, in addition to procyanidin dimers and trimers and procyanidin polymers. Oligomeric proanthocyanidins from grape seeds have been shown to have an antioxidant potency 20 times greater than vitamin C and 50 times that of vitamin E.55
Grape seed catechin and epicatechin are rapidly absorbed, metabolized, and excreted in the urine (27% and 36%, respectively).56 Procyanidins are well-absorbed, antimutagenic, and nontoxic. They serve as free radical scavengers to reduce LDL oxidation and CHD.43,55 Research suggests they can help protect against damage due to cardiac ischemia57 and irradiation from the sun, while improving circulation, vision, and joint flexibility.43,55 They reduced peripheral venous insufficiency in several clinical studies.43 When fed to rats at a dose of 75 mg/kg for nine weeks, grape seed extract with 40% proanthocyanidins reduced markers of lipid and protein oxidation in the brain, especially the hippocampus and cerebellum. In addition, increased acetylcholine and reduced acetylcholinesterase activity in the cerebral cortex suggests enhanced cognition for older rats.58 The proteomics of a 5% grape seed extract diet for six weeks on rat brains are in the opposite direction of changes seen in Alzheimer's disease, suggestive of neuroprotective activity.59
Conclusion
Due to their radical-scavenging and antioxidant activities, the wide varieties of polyphenolics, stilbenes, carotenoids, and other bioactive substances in berries and choice fruit are helpful for maintaining and protecting health. In a world where exposure to damaging synthetic xenobiotic chemicals is a daily reality, reducing the risk from foreign substances is important in avoiding cellular and tissue damage that can predispose people to chronic diseases.
The consumption of the whole fruit, rather than just the fraction soluble in its juice, is the best means of deriving the most benefit. Since the phytochemical composition of fruit is variable depending on growing conditions, harvesting, processing, and storage, relying on occasional or even daily consumption of only one or several fruits to provide meaningful amounts of the broad spectrum of protective nutrient and non-nutritive agents is an unnecessary gamble. The optimal solution is to enjoy a combination of different types of fruit to provide a panoply of phytochemical adjuvants.
Consuming a variety of different sources of essential and adjunctive compounds is a practical means of addressing health concerns. Fruits and berries have been shown scientifically to help reduce or avoid dysfunctional biochemical conditions. One means of addressing many modern ills lies in consuming these traditional foods. Berries and fruit, known for their marvelous flavors and colorful appearances, are now also appropriately recognized for their life-enhancing qualities and health-ensuring complex combinations of phytochemicals. After millenia, we can affirm the advice espoused by the father of medicine, Hippocrates: "Let your food be your medicine, and your medicine be your food."
Recommendation
Although specific recommendations would depend on the particular fruit, in general:
- Organic fruit is preferable when available.
- Examine and wash fresh fruit prior to consuming, retaining undamaged edible peels.
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Without taking convenience into account, the most preferable forms of fruit/berries are listed in rank order in the Figure, above.
References
1. United States Department of Agriculture. Available at: www.health.gov/DietaryGuidelines/dga2005/document/htmL/chapter5.htm. Accessed Sept. 4, 2008.
2. United States Department of Agriculture Food Pyramid. Available at: www.mypyramid.gov/pyramid/fruits_amount.aspx. Accessed Sept. 4, 2008.
3. American Heart Association. Available at: www.americanheart.org/presenter.html?identifier=4774. Accessed Sept. 4, 2008.
4. American Cancer Society. Available at: www.cancer.org/docroot/PED/content/PED_3_2X_Hints_for_Eating_Smart_with_Fruits_and_Vegetables.asp. Revised on Sept. 28, 2006. Accessed Sept. 4, 2008.
5. Miller NJ, Ruiz-Larrea MB. Flavonoids and other plant phenols in the diet: Their significance as antioxidants. J Nutrit Envir Med 2002;12:39-51.
6. Seeram NP. Berry fruits: Compositional elements, biochemical activities, and the impact of their intake on human health, performance, and disease. J Agric Food Chem 2008;56:627-629.
7. Beekwilder J, et al. Antioxidants in raspberry: On-line analysis links antioxidant activity to a diversity of individual metabolites. J Agric Food Chem 2005;53:3313-3320.
8. Seeram NP, Nair MG. Inhibition of lipid peroxidation and structure-activity-related studies of the dietary constituents anthocyanins, anthocyanidins, and catechins. J Agric Food Chem 2002;50:5308-5312.
9. Hakkinen S, Auriola S. High-performance liquid chromatography with electrospray ionization mass spectrometry and diode array ultraviolet detection in the identification of flavonol aglycones and glycosides in berries. J Chromatogr A 1998;829:91-100.
10. Hakkinen SH, et al. Content of the flavonols quercetin, myricetin, and kaempferol in 25 edible berries. J Agric Food Chem 1999;47:2274-2279.
11. Amakura Y, et al. Influence of jam processing on the radical scavenging activity and phenolic content in berries. J Agric Food Chem 2000;48:6292-6297.
12. Vinson JA, et al. Dried fruits: Excellent in vitro and in vivo antioxidants. J Am Coll Nutr 2005;24:44-50.
13. Mink PJ, et al. Flavonoid intake and cardiovascular disease mortality: A prospective study in postmenopausal women. Am J Clin Nutr 2007;85:895-909.
14. Halvorsen BL, et al. Content of redox-active compounds (ie, antioxidants) in foods consumed in the United States. Am J Clin Nutr 2006;84:95-135.
15. Wu X, et al. Lipophilic and hydrophilic antioxidant capacities of common foods in the United States. J Agric Food Chem 2004;52:4026-4037.
16. Negri E, et al. Vegetable and fruit consumption and cancer risk. Int J Cancer 1991;48:350-354.
17. Pavia M, et al. Association between fruit and vegetable consumption and oral cancer: A meta-analysis of observational studies. Am J Clin Nutr 2006;83:1126-1134.
18. Vainio H, Weiderpass E. Fruit and vegetables in cancer prevention. Nutr Cancer 2006;54:111-142.
19. Seeram NP. Berry fruits for cancer prevention: Current status and future prospects. J Agric Food Chem 2008; 56:630-635.
20. Takachi R, et al. Fruit and vegetable intake and risk of total cancer and cardiovascular disease: Japan Public Health Center-Based Prospective Study. Am J Epidemiol 2008;167:59-70.
21. Joshipura KJ, et al. Fruit and vegetable intake in relation to risk of ischemic stroke. JAMA 1999;282:1233-1239.
22. Barberger-Gateau P, et al. Dietary patterns and risk of dementia. The Three-City cohort study. Neurology 2007;69:1921-1930.
23. Shukitt-Hale B, et al. Berry fruit supplementation and the aging brain. J Agric Food Chem 2008;56:636-641.
24. Kuzminski LN. Cranberry juice and urinary tract infections: Is there a beneficial relationship? Nutr Rev 1996;54(11 Pt 2):S87-S90.
25. Kontiokari T, et al. Dietary factors protecting women from urinary tract infection. Am J Clin Nutr 2003;77:600-604.
26. Leahy M, et al. Latest developments in cranberry health research. Pharmaceut Biol 2002;40:50-54.
27. McKay DL, Blumberg JB. Cranberries (Vaccinium macrocarpon) and cardiovascular disease risk factors. Nutr Rev 2007;65:490-502.
28. Bailey DT, et al. Can a concentrated cranberry extract prevent recurrent urinary tract infections in women? A pilot study. Phytomedicine 2007;14:237-241.
29. Ruel G, et al. Low-calorie cranberry juice supplementation reduces plasma oxidized LDL and cell adhesion molecule concentrations in men. Br J Nutr 2008;99:352-359.
30. Duthie SJ, et al. The effects of cranberry juice consumption on antioxidant status and biomarkers relating to heart disease and cancer in healthy human volunteers. Eur J Nutr 2006;45:113-122.
31. Duthie GG, et al. Increased salicylate concentrations in urine of human volunteers after consumption of cranberry juice. J Agric Food Chem 2005;53:2897-2900.
32. Rimando AM, et al. Resveratrol, pterostilbene, and piceatannol in vaccinium berries. J Agric Food Chem 2004;52:4713-4719.
33. Seeram NP, et al. Total cranberry extract versus its phytochemical constituents: Antiproliferative and synergistic effects against human tumor cell lines. J Agric Food Chem 2004;52:2512-2517.
34. Kresty LA, et al. Cranberry proanthocyanidins induce apoptosis and inhibit acid-induced proliferation of human esophageal adenocarcinoma cells. J Agric Food Chem 2008;56:676-680.
35. Hager TJ, et al. Processing and storage effects on monomeric anthocyanins, percent polymeric color, and antioxidant capacity of processed blackberry products. J Agric Food Chem 2008;56:689-695.
36. Hager TJ, et al. Ellagitannin composition of blackberry as determined by HPLC-ESI-MS and MALDI-TOF-MS. J Agric Food Chem 2008;56:661-669.
37. Daniel EM, et al. Extraction, stability, and quantitation of ellagic acid in various fruits and nuts. J Food Comp Anal 1989;2:338-349.
38. Barch DH, et al. Ellagic acid induces transcription of the rat glutathione S-transferase-Ya gene. Carcinogenesis 1995;16:665-668.
39. Barch DH, Rundhaugen LM. Ellagic acid induces NAD(P)h:quinone reductase through activation of the antioxidant responsive element of the rat NAD(P)H:quinone reductase gene. Carcinogenesis 1994;15:2065-2068.
40. Narayanan BA, et al. p53/p21(WAF1/CIP1) expression and its possible role in G1 arrest and apoptosis in ellagic acid treated cancer cells. Cancer Lett 1999;136:215-221.
41. Mertens-Talcott SU, Percival SS. Ellagic acid and quercetin interact synergistically with resveratrol in the induction of apoptosis and cause transient cell cycle arrest in human leukemia cells. Cancer Lett 2005;218:141-151.
42. Stoner GD, et al. Protection against esophageal cancer in rodents with lyophilized berries: Potential mechanisms. Nutr Cancer 2006;54:33-46.
43. Bombardelli E, Morazzoni P. Vitis vinifera L. Fitoter 1995;66:291-317.
44. Stein JH, et al. Purple grape juice improves endothelial function and reduces the susceptibility of LDL cholesterol to oxidation in patients with coronary artery disease. Circulation 1999;100:1050-1055.
45. Arendt BM, et al. Single and repeated moderate consumption of native or dealcoholized red wine show different on antioxidant parameters in blood and DNA strand breaks in peripheral leukocytes in healthy volunteers: A randomized controlled trial. Nutr J 2005;4:33.
46. Tsang C, et al. The influence of moderate red wine consumption on antioxidant status and indices of oxidative stress associated with CHD in healthy volunteers. Br J Nutr 2005;93:233-240.
47. Pace-Asciak CR, et al. The red wine phenolics trans-resveratrol and quercetin block human platelet aggregation and eicosanoid synthesis: Implications for protection against coronary heart disease. Clin Chim Acta 1995;235:207-219.
48. Piver B, et al. Involvement of cytochrome P450 1A2 in the biotransformation of trans-resveratrol in human liver microsomes. Biochem Pharmacol 2004;68:773-782.
49. Potter GA, et al. The cancer preventative agent resveratrol is converted to the anticancer agent piceatoannol by the cytochrome P450 enzyme CYP1B1. Br J Cancer 2002;86:774-778.
50. Jang M, et al. Cancer chemopreventive activity of resveratrol, a natural product derived from grapes. Science 1997;275:218-220.
51. Ciolino HP, Yeh GC. Inhibition of aryl hydrocarbon-induced cytochrome P-450 1A1 enzyme activity and CYP1A1 expression by resveratrol. Mol Pharmacol 1999;56:760-767.
52. Pignatelli P, et al. Polyphenols synergistically inhibit oxidative stress in subjects given red and white wine. Atherosclerosis 2006;188:77-83.
53. Offman EM, et al. Red winecisapride interaction: Comparison with grapefruit juice. Clin Pharmacol Ther 2001;70:17-23.
54. Tsunoda SM, et al. Red wine decreases cyclosporine bioavailability. Clin Pharmacol Ther 2001;70:462-467.
55. Shi J, et al. Polyphenolics in grape seedsbiochemistry and functionality. J Med Food 2003:6:291-299.
56. Tsang C, et al. The absorption, metabolism and excretion of flavan-3-ols and procyanidins following the ingestion of a grape seed extract by rats. Br J Nutr 2005;94:170-181.
57. Sato M, et al. Cardioprotective effects of grape seed proanthocyanidin against ischemic reperfusion injury. J Mol Cell Cardiol 1999;31:1289-1297.
58. Devi SA, et al. Grape seed proanthocyanidin extract (GSPE) and antioxidant defense in the brain of adult rats. Med Sci Monit 2006;12:BR124-BR129.
59. Kim H, et al. Proteomics analysis of the actions of grape seed extract in rat brain: Technological and biological implications for the study of the actions of psychoactive compounds. Life Sci 2006;78:2060-2065.
The United States Department of Agriculture (USDA) Dietary Guidelines for Americans 2005 states: "Compared with the many people who consume a dietary pattern with only small amounts of fruits and vegetables, those who eat more generous amounts as part of a healthful diet are likely to have reduced risk of chronic diseases, including stroke and perhaps other cardiovascular diseases, type 2 diabetes, and cancers in certain sites [oral cavity and pharynx, larynx, lung, esophagus, stomach, and colon-rectum]. Diets rich in foods containing fiber, such as fruits, ... may reduce the risk of coronary heart disease."Subscribe Now for Access
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