Dried Fruits: Underconsumed But Oh So Nutritious

June 2017 Issue

Dried Fruits: Underconsumed But Oh So Nutritious
By Kaleigh McMordie, MCN, RDN, LD
Today's Dietitian
Vol. 19, No. 6, P. 11

Dried fruits, such as raisins, prunes, apricots, and figs, have been around for centuries. Evidence of drying fruits as a means of preserving them for later consumption and various culinary applications dates back as early as 12,000 BC when fruits were left to dry in the hot sun. Later, tunnels and "still houses" with fires were used to preserve fruits where the sunlight wasn't strong enough to dry them.1

Similar methods using sunlight or heat with minimal processing or additives are used today to dry traditional fruits such as dates, ﬁgs, prunes, raisins, apricots, peaches, apples, and pears. Nontraditional dried fruits such as blueberries, cranberries, cherries, strawberries, and mangoes may or may not be infused with sugar solutions, fruit juice concentrates, or preservatives like sulfites before drying. While the FDA deems sulfites generally recognized as safe for preserving color and freshness in dried fruits, some clients may have concerns about them, so recommend they read the labels. Some products sold as dried fruit, such as papayas and pineapples, may not be dried fruit at all but rather candied fruit.2 If the package says "crystallized," then it's candied fruit.

Technological advances have led to alternative drying methods that are more efficient than sun drying, enabling dried fruit to retain all of its nutrients. Sun drying can take longer to produce results if temperatures aren't hot enough; if temperatures are too hot, the fruit may not retain all of its nutrients. Modern methods of heat-drying fruit include osmotic dehydration, a partial dehydration method that requires little energy but allows for more efficient drying; vacuum drying, which uses low heat; microwave convection drying, which uses electrical waves for reduced drying time and energy consumption; and freeze-drying, which doesn't involve heat but allows for better quality and nutrient retention.3

Nutrition
Dried fruit is a valuable source of vitamins, minerals, fiber, and phytochemicals; it's shelf stable and a palatable, convenient snack for those on the go. Yet, despite its nutrient profile and numerous health benefits, dried fruit is significantly underconsumed as a source of nutrition in the United States, with only 6.9% of Americans reporting eating any dried fruit at all.4 With new technologies providing more efficient drying options, dried fruit can help clients better meet their daily nutrient needs.

Dried fruit is dehydrated into a concentrated form of whole fruit, so the portion size is much smaller than a serving of fresh fruit (typically half the size of fresh fruit). One-quarter cup or about 40 g is a standard serving for most dried fruit. A small amount is considered nutrient dense, providing a significant amount of dietary fiber and potassium. Many also contain magnesium, iron, calcium, and phosphorus. While individual nutrient content varies by fruit, dried fruit generally contains all of the vitamins and minerals the original fresh fruit provides.4 A couple of exceptions include vitamin C and thiamin, which can be destroyed by heat, though freeze-drying may help to retain some of these vitamins.3 One of the greatest nutritional benefits of dried fruits is the level of phytochemicals they contain such as phenolic acids, ﬂavonoids (anthocyanidins, ﬂavan-3-ols, ﬂavones, ﬂavonols, and isoﬂavones), phytoestrogens, and carotenoids, among others. Phenolic compounds make up the largest percentage of phytochemicals in the diet, and dried fruit is an excellent source of these compounds that are responsible for much of the antioxidant activity in fruits and vegetables.4 Dried fruit is nutrient dense, but it's also calorically dense, so portion control is important. As Vicki Shanta Retelny, RDN, a speaker and writer based in Chicago and author of The Essential Guide to Healthy Healing Foods, explains, "A handful goes a long way!"

There's some concern about the amount of sugar in dried fruits, but in unsweetened varieties, the sugar occurs naturally and doesn't much affect glycemic response. Dried fruits are largely made from naturally occurring fructose and glucose; some contain sorbitol, which generally promotes a stable insulin response.2 The 2015–2020 Dietary Guidelines for Americans recommend reducing added sugars, including those that occur naturally as in honey and fruit juices; however, dried fruit that doesn't contain added sugars is considered a whole fruit.5 Some dried fruits are sweetened with added sugars, so people with diabetes may need to limit them. Chelsey Amer, MS, RDN, a nutrition consultant, healthful food blogger, recipe developer, and creator of C It Nutritionally in New York City, says not to fear dried fruit but choose unsweetened varieties since they're naturally sweet. "If you choose dried fruit with minimal sugar, the fiber, vitamins, and minerals far outweigh a little bit of sweetness," she says.

Health Benefits
In general, fruit is part of a healthful eating pattern associated with reduced risk of cardiovascular disease (CVD), type 2 diabetes, certain cancers, and obesity. It provides important vitamins, minerals, fiber, and phytochemicals.4 Yet, data from the 2009–2010 National Health and Nutrition Examination Survey show that 75% of the US population consumes less than the recommended two cup-equivalents of whole fruit daily.4

Traditional dried fruits (those that don't contain added sugars and are dried with minimal processing) such as raisins, prunes, dates, and figs, have similar nutrient profiles to their whole counterparts and, as a result, provide many of the same benefits.4 They're also high in fiber and phytochemicals, since both of these nutrients are concentrated in dried fruits.2 This combination of fiber and phytonutrients appears to be responsible for many of the health benefits of consuming dried fruit, which include lower risk of CVD related to dried fruit's blood pressure-lowering effects, lower postprandial glycemic response, and possible improvement of lipid profiles.4 Dried fruits also may contribute to colon health due to their prebiotic fiber compounds, which serve as fuel for healthy bacteria to maintain digestive health.2 Epidemiologic data suggest that those who eat dried fruit have higher overall diet quality, lower incidence of type 2 diabetes, and lower body weight and waist circumference than those who don't consume dried fruit.4 The high polyphenol content of dried fruit also may be protective against cancer because of its anti-inflammatory and antioxidant activity.2

Raisins
The most studied of all the traditional dried fruits are raisins. Raisin consumption has been shown to reduce postprandial and fasting blood glucose, hemoglobin A1c, and systolic blood pressure in men and women compared with other commercially available processed snacks, such as cheese-flavored crackers or graham crackers, most likely due to raisins' high fiber content.6,7 Studies also have shown raisins to be beneficial in lowering diastolic blood pressure and improving total and LDL cholesterol levels, as well as oxidized LDL.7,8

Cranberries
Research on cranberries is dominated by the effects of cranberry juice or raw cranberries on urinary tract infections (UTIs); however, emerging data suggest that dried cranberries, even sweetened, can provide benefits due to their high levels of fiber and polyphenolic compounds, particularly proanthocyanidins.9,10 One study found that sweetened dried cranberries retain comparable amounts of proanthocyanidins and have a similar oxygen radical absorbance capacity to cranberry juice cocktail, in addition to dietary fiber.11 Dried cranberries have been proven effective at preventing recurrent UTIs in women and lower urinary tract symptoms in men.12,13 The polyphenols found in cranberries may be effective in regulating insulin and glycemic responses in type 2 diabetes.14 Research also has found that unsweetened and even lightly sweetened dried cranberries produce favorable glycemic and insulinemic responses in adults with type 2 diabetes.9,14 Moreover, emerging evidence suggests that the metabolites and polyphenols found in cranberries can positively affect the gut microbiota, though more research is needed.9

Prunes
Dried plums, or prunes, are known to have high amounts of polyphenols with anti-inflammatory and antioxidant effects.15 They're also a good source of fiber, potassium, magnesium, phosphorus, boron, and iron. Daily consumption of dried plums has been shown to improve markers of CVD risk, including total cholesterol, inflammatory markers, and oxidative stress.15,16 Recent research also has proven the effectiveness of dried plums in preventing and even reversing bone loss in postmenopausal women. They may even protect bones in those exposed to ionizing radiation, including astronauts, cancer patients undergoing radiation therapy, and radiation workers.17-19 Furthermore, due to their high fiber content and polyphenolic compounds that produce a mild laxative effect, prunes promote colon health by relieving constipation and possibly preventing colon cancer.18 These components also help slow the postprandial glycemic response, making prunes a suitable snack for people with diabetes.18,20,21

Sustainability
In addition to dried fruits' nutrient profile and health benefits is their sustainability. Fruit is a highly perishable food and requires low temperatures and quick handling throughout the distribution chain to reach consumers safely and retain maximum nutritional benefit. Preserving the freshness and integrity of fresh fruit is both costly and burdensome and still results in loss of nutrients and even sellable product. Drying fruit has been a sustainable means of reducing waste postharvest for centuries. It's estimated that 20% of global perishables are dried, promoting food security and sustainability while preserving nutrition, increasing shelf life and stability, and reducing transport packing requirements, weight, and volume.3 Drying fruit enables producers to reduce loss, resulting in higher profits as well as savings for consumers in the off-season.

Practice Pearls
Dried fruit has several applications that can be beneficial to various clients. It can be a valuable addition to the diets of those who struggle to get their daily fruit servings or enough nutrients, especially children or older adults. It may be wise to recommend dried plums to those at risk of osteoporosis or those who already have it, and cranberries may help clients with recurrent UTIs who can't drink cranberry juice because of its impact on blood sugar. Dried fruit also can be a nutrient-dense replacement for sugar, especially in baked goods, and can add flavor and texture to meals. Amer adds raisins to oatmeal, includes Craisins in salads, and loves dried mangoes as a dessert. Recommending dried fruit for snacks or desserts is a great idea for clients with a sweet tooth. Nutrient-dense fruits can satisfy sweet cravings and may replace other sugary snacks that offer little nutritional value and may cause a rapid increase in blood sugar.

It's important to educate clients on the benefits of dried fruit but to emphasize choosing unsweetened varieties for maximum benefit.

When it comes to making recommendations for clients, dietitians need to consider the individual and his or her health status, lifestyle, and values. Ultimately, it's the client's choice, and the RD should provide evidence-based guidance and support.

— Kaleigh McMordie, MCN, RDN, LD, is a dietitian based in Lubbock, Texas, and creator of the food blog Lively Table. She specializes in culinary nutrition and a nondiet approach to health and wellness. Follow her on social media @livelytable.

References
1. Nummer BA. Historical origins of food preservation. National Center for Home Food Preservation website. http://nchfp.uga.edu/publications/nchfp/factsheets/food_pres_hist.html. Published May 2002. Accessed April 12, 2017.

2. Alasalvar C, Shahidi F, eds. Dried Fruits: Phytochemicals and Health Effects. Ames, IA: Wiley-Blackwell; 2013.

3. Sagar VR, Suresh Kumar P. Recent advances in drying and dehydration of fruits and vegetables: a review. J Food Sci Technol. 2010;47(1):15-26.

4. Carughi A, Feeney MJ, Kris-Etherton P, et al. Pairing nuts and dried fruit for cardiometabolic health. Nutr J. 2016;15:23.

5. US Department of Health & Human Services. 2015–2020 Dietary Guidelines for Americans: shifts needed to align with healthy eating patterns: current eating patterns in the United States. https://health.gov/dietaryguidelines/2015/guidelines/chapter-2/current-eating-patterns-in-the-united-states/. Published January 7, 2016. Accessed April 12, 2017.

6. Anderson JW, Weiter KM, Christian AL, Ritchey MB, Bays HE. Raisins compared with other snack effects on glycemia and blood pressure: a randomized, controlled trial. Postgrad Med. 2014;126(1):37-43.

7. Bays H, Weiter K, Anderson J. A randomized study of raisins versus alternative snacks on glycemic control and other cardiovascular risk factors in patients with type 2 diabetes mellitus. Phys Sportsmed. 2015;43(1):37-43.

8. Barnes JL, Holt R, Schramm D, Waters AR, Painter JE, Keen C. Raisin consumption may lower circulating oxidized LDL levels, potentially decreasing the risk for coronary artery disease. J Acad Nutr Diet. 2011;111(9):A46.

9. Blumberg JB, Basu A, Krueger CG, et al. Impact of cranberries on gut microbiota and cardiometabolic health: proceedings of the Cranberry Health Research Conference 2015. Adv Nutr. 2016;7(4):759S-770S.

10. Grace MH, Massey AR, Mbeunkui F, Yousef GG, Lila MA. Comparison of health-relevant flavonoids in commonly consumed cranberry products. J Food Sci. 2012;77(8):H176-H183.

11. Marais J, Khoo C. Polyphenolic content of sweet dried cranberries compared to cranberry juice cocktail. FASEB J. 2013;27(1 Suppl):1079.19.

12. Burleigh AE, Benck SM, McAchran SE, et al. Consumption of sweetened, dried cranberries may reduce urinary tract infection incidence in susceptible women — a modified observational study. Nutr J. 2013;12(1):139.

13. Vidlar A, Vostalova J, Ulrichova J, et al. The effectiveness of dried cranberries (Vaccinium macrocarpon) in men with lower urinary tract symptoms. Br J Nutr. 2010;104(8):1181-1189.

14. Wilson T, Luebke JL, Morcomb EF, et al. Glycemic responses to sweetened dried and raw cranberries in humans with type 2 diabetes. J Food Sci. 2010;75(8):H218-H223.

15. Chai SC, Hooshmand S, Saadat RL, Payton ME, Brummel-Smith K, Arjmandi BH. Daily apple versus dried plum: impact on cardiovascular disease risk factors in postmenopausal women. J Acad Nutr Diet. 2012;112(8):1158-1168.

16. Nakamichi-Lee M, Hooshmand S, Kern M, Ahouraei A, Hong MY. Dried plum consumption improves antioxidant capacity and reduces inflammation in postmenopausal women. FASEB J. 2016;30(1 Suppl):1174.19.

17. Hooshmand S, Chai SC, Saadat RL, Payton ME, Brummel-Smith K, Arjmandi BH. Comparative effects of dried plum and dried apple on bone in postmenopausal women. Br J Nutr. 2011;106(6):923-930.

18. Stacewicz-Sapuntzakis M, Bowen PE, Hussain EA, Damayanti-Wood BI, Farnsworth NR. Chemical composition and potential health effects of prunes: a functional food? Crit Rev Food Sci Nutr. 2001;41(4):251-286.

19. Metti D, Ortiz D, Cravinho A, et al. The effectiveness of daily consumption of 50 g dried plum on improving indices of bone turnover in osteopenic postmenopausal women. FASEB J. 2014;28(1 Suppl):1027.5.

20. Stacewicz-Sapuntzakis M. Dried plums and their products: composition and health effects — an updated review. Crit Rev Food Sci Nutr. 2013;53(12):1277-1302.

21. Hooshmand S, Garcia S, Metti D, Vereda Y, Chai SC, Arjmandi BH. Long-term effects of dried plum consumption on insulin and glucose levels in postmenopausal women. FASEB J. 2013;27(1 Suppl):lb317.