Research Shows Strawberries
Can Be A Boost To Overall Health
By Leslie Redmond, Phd MS RDN
October 2018 – Strawberries are universally loved by consumers. In a recent survey among primary grocery shoppers, 32 percent named strawberries as their favorite fruit — significantly higher than any other variety. With nearly 90 percent of the nation’s fresh strawberries grown on family farms in California, strawberries are widely available at acceptable prices. Not only are they the most available and affordable berry on the market, but they are also exceptionally healthy. Berries are nutrient-dense; strawberries provide 110 percent of the recommended daily value for vitamin C, 3 grams of heart-healthy fiber, blood pressure-regulating potassium and chronic disease-preventing antioxidants at only 50 calories and 8 grams of sugar per 1-cup serving.
At a time when diet-related chronic diseases, such as obesity, Type 2 diabetes and heart disease, are affecting millions of Americans, the value of nutrient density cannot be overlooked. Unfortunately, berry consumption accounts for only 10 percent of total fruit consumption among U.S. adults.1 As health professionals strive to influence consumers to increase fruit consumption, it is important to investigate the health benefits of berries so consumers are empowered to make informed and intentional dietary choices in support of their health.
For more than a decade, the California Strawberry Commission (CSC) has supported nutrition research with the goal of increasing awareness, improving understanding, and realizing the potential of the extraordinary health benefits of strawberries. Current areas of exploration include clinical human trials in heart health, metabolic function, inflammation, cognition and even bone health, with the largest bodies of evidence established for prevention of cardiovascular disease (CVD), improvement of insulin sensitivity and delayed cognitive decline associated with aging.
Heart disease. Research conducted by Arpita Basu and colleagues (2014) at Oklahoma State University examined whether freeze-dried strawberries (FDS) improved lipid and lipoprotein profiles and lowered markers of inflammation in overweight and hypercholesterolemic adults.2 In this study, 60 volunteers were randomized to consume one of four beverages ranging in dose of FDS once a day for 12 weeks. Results revealed significantly greater decreases in total and LDL cholesterol among participants randomized to the high-dose FDS beverage (50 g/day) as compared to the low-dose FDS (25 g/day) and control.
Type 2 diabetes. The American Diabetes Association includes strawberries as a top 10 superfood for diabetics because of their high fiber, low sugar and low glycemic index. The CSC has supported research that contributes to this superfood status. Eunyoung Park and colleagues (2016) at Illinois Institute of Technology investigated the dose-response relationship of strawberries on post-meal glucose and insulin concentrations.3 Twenty-one adults with insulin resistance were randomized to consume a high-fat meal with one of four beverages ranging from 0 g FDS to 40 g FDS. Analysis showed post-meal insulin concentrations were significantly reduced after the 40g FDS beverage compared with the other beverages, indicating strawberries reduced the amount of insulin needed for metabolism.
Cognition. Some age-related cognitive decline is normal: recent memories, tasks that require divided attention, word retrieval, and speed of cognitive and motor processes all experience some degree of decline with age. However, there are lifestyle behaviors that help counter this decline — including eating more strawberries. Elizabeth Devore and colleagues at Brigham and Women’s Hospital in Boston (2012) analyzed data from the Nurses’ Health Study and found greater intakes of strawberries were associated with slower rates of cognitive decline and concluded that berry intake appeared to delay cognitive aging by up to 2.5 years.4
Research in these areas has led to the observation that consuming one serving of strawberries at least three times per week can improve health. These findings are easily translated to consumers with the catch phrase “8-a-day.” In other words, just eight strawberries a day, a few days per week, is all it takes to benefit from health-promoting strawberries.
Scientifically supported health benefits, in addition to consumers’ natural affinity for strawberries, have helped make these berries a go-to choice for any occasion. Their versatile flavor profile makes them an easy addition to main dishes and desserts alike, and their nutrient profile allows them to fit into nearly any dietary plan, leaving strawberries poised to remain Americans’ favorite fruit as consumers and health professionals seek out more nutrient-dense, whole food options to improve health through diet.
1 Healthy People 2020. Available at https://bit.ly/1kzjABq
2 Basu A, Betts NM, Nguyen A, Newman ED, Fu D, Lyons TJ. Freeze-dried strawberries lower serum cholesterol and lipid peroxidation in adults with abdominal adiposity and elevated serum lipids. J Nutr. 2014;144:830-837.
3 Park E, Edirisinghe I, Wei H, Vijayakumar LP, Banaszewski K, Cappozzo JC, Burton-Freeman, B. A dose-response evaluation of freeze-dried strawberries independent of fiber content on metabolic indices in abdominally obese individuals with insulin resistance in a randomized, single-blinded, diet-controlled crossover trial. Mol Nutr Food Res. 2016;60:1099-1109.
4 Devore EE, Kang JH, Breteler MMB, Grodstein F. Dietary intakes of berries and flavonoids in relation to cognitive decline. Ann Neurol. 2012;72:135-143.
Eat Eight Strawberries, But Consider These Eight Research Principles
By Jim Prevor, Editor-In-Chief, Produce Business
The produce industry is fortunate to have such wonderful products to sell. They are generally beautiful, delicious and healthy. They have the endorsement of public health authorities and, increasingly, individual commodities are producing research that details benefits of consumption. Yet, overall consumption is not increasing. Oh sure, individual products may boom for all kinds of reasons — kale, blueberries, Brussels sprouts and pomegranates all have experienced booms because of technology, research related to health claims, culinary trends and much more.
Certainly, for all the reasons detailed in this Research Perspective and many more, strawberries have seen an increase in consumption. Clever marketing campaigns have done a great job of communicating messages, such as the desirability of eating eight strawberries every day.
Indeed, whereas bananas were once the King Category within produce at almost every retailer, berries — with a substantial assortment, a boom in organic, availability from Mexico, high-quality proprietary varieties and excellent branding — are now the No. 1 category at almost all retailers.
Yet, for the industry as a whole, the kind of research being done is mostly just moving volume around the category. So, people who would have had spinach buy kale, and those who would have bought another snack fruit buy some berries. None of it has been sufficient to boost overall produce consumption.
Why? The research seems to always have the same limitations. Let me lay out the eight principles that produce research has to transcend if we are to boost the overall produce consumption based on health findings:
- Prove the nutrients are needed
It is a nice talking point to mention that a produce item is high in, say, vitamin C, but is the population short of vitamin C? Are many people in danger of getting scurvy? First rule of marketing: Sell the benefits not the feature. Having a vitamin is a feature — not a benefit.
- Don’t sell markers, sell end points
Lots of research establishes that one produce item or another is somehow associated with a marker such as inflammation or a higher or lower cholesterol number, but what is the endpoint? People care about these things because of a possibility they may reduce the likelihood of heart attacks or stroke. Is our research strong enough to make that claim?
- Beware of marketing terms
It has been a boon for individual items to be given labels such as Superfoods. But these are not universally accepted scientific terms and have no clear meaning. It makes consumers skeptical to use words that don’t clearly mean things.
- Causation, not association
Studies that show association are really just signs the industry should invest in research as to causation. Produce is very vulnerable in this area as it is known to be healthy. So, consumers interested in healthy living will gravitate to produce and to many other healthy lifestyle choices, from exercise to meditation to not smoking. To have the kind of breakthroughs in consumption we need, we must be able to say specifically that more consumption will cause better outcomes.
- Beware of self-reporting
Consumer recollection of eating habits is notoriously poor. Yet much industry research depends on data that consumers supply as to what they claim or remember they ate. Not only are memories often faulty, but it is not a neutral decision to simply say they ate a salad or fried chicken, so consumers often overstate their consumption of fresh produce.
- Replacement versus addition
Many claims about the benefits of increased produce consumption revolve around general principles about the causes of obesity. The general industry program of Fruit & Veggies — More Matters has always tried to skate this ambiguity. The basis for the claim is that more consumption of produce will lead to less consumption of something else. The evidence that increasing one’s calorie consumption by adding a serving of produce will result in better health outcomes is thin indeed.
- Scale of studies
Many produce-related health studies are small and unduplicated. It is not uncommon for these studies to have only 50 or 60 participants and to have been done one time, in one place. If the industry is going to really motivate change in eating behavior, we need to have larger studies that are reproduced by multiple institutions.
- Fresh produce
Many studies use juice, dried product, freeze-dried product, powdered product, etc., typically because it is easier. But if we want to persuade people that the benefits are derived from eating fresh product, that is what we ought to use in our industry-funded studies.
So, let’s hope consumers eat their eight strawberries a day and that the industry thinks about these eight principles in funding the kinds of research that may actually boost overall produce consumption.