Health Benefits of Strawberries

health-benefits-of-strawberries

In our Healthiest Way of Eating Plan, we encourage the consumption of 5-10 servings of fruits-plus-vegetables (combined) each 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.

The fragrantly sweet juiciness and deep red color of strawberries can brighten up both the taste and aesthetics of any meal. Not only do they taste great they are among the fruits and vegetables ranked highest in health-promoting antioxidants. Antioxidants help combat the damaging effects of free radical activity to cellular structures and DNA. Like the other World’s Healthiest Fruits, we recommend enjoying strawberries raw (not in baked/cooked desserts) because they provide you with the best flavor and the greatest benefits from their vast array of nutrients and digestion-aiding enzymes. Peoples around the world have long been eating fruit for dessert, not only as a delicious ending to a meal but as a great digestive aid as well. For more on the Healthiest Way of Preparing Strawberries, see below.

Nutrients in
Strawberries
1.00 cup (144.00 grams)
Nutrient%Daily Value


 vitamin C141.1%


 manganese28%


 fiber11.5%


 folate8.6%


 iodine8.6%


 potassium6.2%


 magnesium4.6%


 vitamin K3.9%


 omega-3 fats3.7%


Calories (46)2%


This chart graphically details the %DV that a serving of Strawberries provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Strawberries can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Strawberries, featuring information over 80 nutrients, can be found under the 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

Health Benefits

Given their unique combination of antioxidant and anti-inflammatory nutrients, it’s not surprising to see strong research support for strawberry health benefits in three major areas: (1) cardiovascular support and prevention of cardiovascular diseases (2) improved regulation of blood sugar, with decreased risk of type 2 diabetes, and (3) prevention of certain cancer types including breast, cervical, colon, and esophageal cancer. In this section, we’ll review the outstanding research-based benefits of strawberries in each area.

Cardiovascular Benefits

No area of strawberry health benefits is better documented than benefits for the cardiovascular system. It’s also hard to imagine any other research result, since our heart and blood vessels need everyday protection from oxidative and inflammatory damage, and the antioxidant and anti-inflammatory nutrient content of strawberries is simply outstanding. Among all fruits profiled as the World’s Healthiest Foods, strawberries come out as the best fruit source of a pivotal antioxidant vitamin: vitamin C in several nationwide studies conducted in different countries. In one study that surveyed 66 different fruits consumed by adults in Iran, strawberries not only emerged as the best fruit source of vitamin C, but a source that provided more than twice as much vitamin C (47 milligrams versus 18 milligrams in 3.5 ounces) than the average for fruits as a group. After raspberries and grapes, strawberries also rank as the best fruit source of manganese among the World’s Healthiest Foods. Because of its key role as a cofactor for antioxidant enzyme activity by the enzyme superoxide dismutase (SOD), manganese is considered to be a key antioxidant mineral. Yet, strawberries “claim to fame” in the antioxidant department is really reserved for their phytonutrient content.

Many of the phytonutrients present in strawberries function not only as antioxidants but also as anti-inflammatory nutrients. The chart below shows several of the more important antioxidant and anti-inflammatory nutrients present in fresh, ripe strawberries:

Antioxidant and Anti-Inflammatory Phytonutrients in Strawberries

(* indicates that these are typically in small or trace amounts)

  • Anthocyanins
    • cyanidins
    • pelargonidins
  • Flavonols
    • procyanidins
    • catechins
    • gallocatechins
    • epicatechins
    • kaempferol
    • quercetin
  • Hydroxy-benzoic acids
    • ellagic acid
    • gallic acid
    • vanillic acid*
    • salicylic acid
  • Hydroxy-cinnamic acids
    • cinnamic acid
    • coumaric acid
    • caffeic acid
    • ferulic acid
  • Tannins
    • ellagitannins
    • gallotannins
  • Stilbenes
    • resveratrol

Several research studies have shown that these diverse strawberry phytonutrients actually work together in synergistic fashion to provide their cardiovascular benefits. Decreased oxidation of fats (lipid peroxidation) in the cell membranes of cells that line our blood vessels; decreased levels of circulating fats, including total cholesterol and LDL cholesterol; and decreased activity of angiotensin I-converting enzyme (ACE), an enzyme whose overactivity increases our risk of high blood pressure are results that have all been documented following daily intake of strawberries over 1-3 months period of time. Amounts of strawberries in most studies were equivalent to 1-2 cups of strawberries per day.

Blood Sugar Benefits

One of the more recent areas of health benefit to be documented in strawberry research is the area of blood sugar benefits. Several recent studies have found regular intake of strawberries to be associated with decreased risk of type 2 diabetes. In some of these studies, frequency of strawberry intake definitely seems to matter since an intake frequency of once per week or less is not associated with blood sugar benefits in some studies. In these studies, significant benefits do not emerge until frequency of intake reaches at least 2-3 strawberry servings per week.

Of special interest for blood sugar regulation is the relationship recently documented by researchers between intake of strawberries, intake of table sugar, and resulting blood sugar levels. As you might expect, excess intake of table sugar (in a serving size of 5-6 teaspoons) was able to produce an unwanted blood sugar spike in study participants during this study. But as you might not expect, this blood sugar spike was actually reduced by simultaneous consumption of strawberries. Approximately one cup of fresh strawberries (approximately 150 grams) was able to decrease blood sugar elevations when table sugar was consumed along with strawberries. The investigators speculated that polyphenols in strawberries played a major role in helping regulate blood sugar response. One particular type of polyphenol in strawberries—ellagitannins—might have been especially important for this blood sugar-relating benefit. Ellaginannins are polyphenols that are known to inhibit the activity of an enzyme called alpha-amylase. Since this enzyme is responsible for breaking amylose starches into simple sugars, fewer simple sugars might be released into the blood stream when activity of this enzyme is reduced.

Anti-Cancer Benefits

Since chronic, excessive inflammation and chronic, excessive oxidative stress (lack of antioxidant nutrients and unsupported oxygen metabolism) are often primary factors in the development of cancer, strawberries would definitely be expected to have cancer risk-lowering properties given their outstanding antioxidant and anti-inflammatory nutrient content. Anti-cancer benefits from strawberries are best documented in the case of breast, cervical, colon, and esophageal cancer. Most of the tumor-inhibiting studies on animals have focused on the phytonutrient content of strawberries. Among the strawberry phytonutrients, ellagic acid and ellagitannins in strawberry have emerged as anti-cancer substances of special interest. While the anti-cancer (chemopreventive) properties of these phytonutrients have yet to be fully understood, their ability to lower risk for some forms of cancer may be related to their ability to boost the activity of antioxidant enzymes like catalase or superoxide dismustase, their ability to lessen the activity of pro-inflammatory enzymes like cyclo-oxygenase 2 (COX-2), or their ability to lessen expression of the enzyme inducible nitric oxide synthase (iNOS). Whatever the mechanism or combination of mechanisms, strawberries are likely to bring anti-cancer health benefits to your diet.

Other Health Benefits

A growing area of health research on strawberries is the area of aging and aging-related events. Several preliminary studies on intake of strawberries on aged animals has shown enhanced cognitive function (in the form of better object recognition) following ingestion of a diet with 2% of the calories provided by strawberry extracts. Enhanced motor function (in the form of better balance and coordination of movements) has also been shown in these strawberry extract studies. Some of the strawberry impact in these aging studies has been attributed to the ability of strawberry phytonutrients to lower the presence of pro-inflammatory messaging molecules like nuclear factor kappa-B.

Improvement of inflammatory bowel problems—including ulcerative colitis and Crohn’s disease—has also been demonstrated in preliminary studies on animals with daily strawberry extract or strawberry powder intake. Interestingly, even though strawberries contain relatively small amounts of salicylic acid (an anti-inflammatory compound very similar to the acetylsalicylic acid of aspirin), some researchers have suggested that this naturally-occurring anti-inflammatory substance in strawberries might be partly responsible for decreased inflammation in the digestive tract of individuals diagnosed with inflammatory bowel diseases like ulcerative colitis or Crohn’s disease.

Inflammation-related arthritis (including rheumatoid arthritis), and inflammation-related diseases of the eye (including macular degeneration) are two additional areas in which strawberries may turn out to provide important health benefits. Even though health research in these areas is in a preliminary stage, the unique combination of anti-inflammatory phytonutrients in strawberries is likely to explain some of the key potential benefits in these areas.

Description

Fragrantly sweet strawberries are the most popular type of berry fruit in the world. Although they have become increasingly available year-round, they are at the peak of their season from April through July when they are the most delicious and most abundant.

While there are more than 600 varieties of strawberries that differ in flavor, size and texture, one can usually identify a strawberry by its red flesh that has small seeds piercing its surface, and a small, regal, green leafy cap and stem that adorn its crown. Most commercially grown strawberries come from the genus-species Fragaria ananassa. Cultivation of this particular genus-species has been taking place for nearly 300 years. Much older still, however, are wild strawberries that typically below to the genus-species Fragaria vesca. Wild strawberries are known to have existed for more than 2,000 years. While typically smaller in size than cultivated strawberries, wild strawberries often feature a more intense flavor. In the U.S., commercial strawberry production is largely limited to the coastal and southern inland regions of California and to the East Coast, where Florida production becomes especially important during the winter months. Fragaria virginiana is a popular genus-species of strawberry grown in the U.S. along side of the genus-species Fragaria ananassa.

History

Strawberries have grown wild for millennia in temperature regions throughout the world. While cultivation of strawberries doesn’t date back this far, it still dates back hundreds and hundreds of years.

It was not until the 18th century, however, when cultivation of strawberries began to be pursued in earnest. In 1714, a French engineer sent to Chile and Peru to monitor Spanish activities in these countries “discovered” a strawberry native to this region that was much larger than those grown in Europe. He brought many samples back to France, which were subsequently planted. These plants did not originally flourish well until a natural crossbreeding occurred between this species and a neighboring North American strawberry variety that was planted nearby in the field. The result was a hybrid strawberry that was large, juicy and sweet, and one that quickly grew in popularity in Europe.

The strawberry, like many other perishable fruits at this time, remained a luxury item only enjoyed by the wealthy until the mid-19th century. Once railways were built and more rapid means of transportation established, strawberries were able to be shipped longer distances and were able to be enjoyed by more people. Today, using a commonplace, layperson’s definition of the word “berry,” the strawberry has become the most popular berry fruit in the world. (In technical scientific terms, this distinction would go to bananas, since their seeds and pulp produced from a single ovary, and that characteristic is used to classify berries versus non-berries. In fact, when considered from a technical scientific standpoint, strawberries are not berries at all, but rather “accessory fruits” in which the delicious substance that we eat is not directly produced from the ovary. But for most of us, despite these technical scientific distinctions, strawberries count as some of the best berries ever!)

How to Select and Store

As strawberries are very perishable, they should only be purchased a few days prior to use. Choose berries that are firm, plump, free of mold, and which have a shiny, deep red color and attached green caps. Since strawberries, once picked, do not ripen further, avoid those that are dull in color or have green or yellow patches since they are likely to be sour and of inferior quality. Full ripe berries will not only have the peak flavor and texture, but will have more nutrients. “Full ripe” in this case means optimally ripe, not overripe. Both underripe and overripe strawberries have been show to have lower vitamin C content and decreased phytonutrient content in comparison to optimally ripe strawberries.

We believe that the surprisingly fragile and perishable nature of strawberries is especially important!

Food scientists have recently taken a close look at storage time, storage temperature, storage humidity, and degree of strawberry ripeness and found significant differences among their impact upon nutrient retention. On average, studies show 2 days as the maximal time for strawberry storage without major loss of vitamin C and polyphenol antioxidants. It’s not that strawberries become dangerous to eat or invaluable after 2 days. It’s just that more storage time brings along with it substantially more nutrient loss. In terms of humidity, 90-95% has been shown to be optimal. Most refrigerators will average a much lower humidity (between 80-90%). Because air circulation inside the fridge can lower humidity, you may want to give your strawberries more storage humidity by putting them in your refrigerator’s cold storage bins (if available). Those cold storage bins will help boost humidity by reducing air circulation. If your refrigerator does not have storage bins, you can use a sealed container for refrigerator storage of your strawberries. Optimal temperature for strawberry storage over a 2-day period has been found to be relatively cold—36F (2C). All public health organizations recommend refrigerator temperatures of 40F (4.4C) as the maximum safe level for food storage.

However, if you are storing sizable amounts of fruits and vegetables—including strawberries—in your refrigerator, you may want to consider setting your refrigerator to a lower-than-maximum temperature setting in the range of 36°-38°F (2°-3°C).

Medium-sized strawberries are often more flavorful than those that are excessively large. If you are buying strawberries prepackaged in a container, make sure that they are not packed too tightly (which may cause them to become crushed and damaged) and that the container has no signs of stains or moisture, indication of possible spoilage. Strawberries are usually available year round, although in greatest abundance from the spring through the mid-summer.

The very fragile nature of strawberries means that great care should be taken in their handling and storage. Before storing in the refrigerator, remove any strawberries that are molded or damaged so that they will not contaminate others. Place the unwashed and unhulled berries in a sealed container to prevent unnecessary loss of humidity. Strawberries will maintain excellent nutrient content if properly stored in a refrigerator for two days. Make sure not to leave strawberries at room temperature or exposed to sunlight for too long, as this will cause them to spoil.

To freeze strawberries, first gently wash them and pat them dry. You can either remove the cap and stem or leave them intact, depending upon what you will do with them once they are thawed. Arrange them in a single layer on a flat pan or cookie sheet and place them in the freezer. Once frozen, transfer the berries to a heavy plastic bag and return them to the freezer where they will keep for up to one year. Adding a bit of lemon juice to the berries will help to preserve their color. While strawberries can be frozen whole, cut or crushed, they will retain a higher level of their vitamin C content if left whole.

Commercial food processing can dramatically lower the nutrient content of strawberries, especially their phytonutrient content. For example, we’ve seen several studies showing very little retention of certain anthocyanin phytonutrients in baby foods made from strawberries or other brightly-colored berries. The dramatic impact of some processing methods may be to do heat, pH (changes in acidity during processing), oxygen exposure, light exposure, the physical and mechanical impact of processing, or a combination of these factors. In any case, a much safer bet in terms of strawberries and nourishment is to stick with fresh berries or carefully frozen berries, and in the case of baby food or the feeding of young children, to purée the berries in a blender so that overall processing is kept to a minimum.

Tips for Preparing and Cooking

Tips for Preparing Strawberries

Since they are very perishable, strawberries should not be washed until right before eating or using in a recipe. Do not remove their caps and stems until after you have gently washed the berries under cold running water and patted them dry. This will prevent them from absorbing excess water, which can degrade strawberries’ texture and flavor. To remove the stems, caps and white hull, simply pinch these off with your fingers or use a paring knife.

Despite their perishable nature, strawberries do appear to hold up well for a day or two in fruit salad if properly stored and chilled. This is good news for those of us who are pressed for time but love fresh fruit salad. And who doesn’t since it’s a perfect addition to any meal and makes a great snack or dessert?

Healthiest Way of Preparing Strawberries

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

How to Enjoy

A Few Quick Serving Ideas

  • Add sliced strawberries to mixed green salad.
  • Layer sliced strawberries, whole blueberries and plain yogurt in a wine glass to make a parfait dessert.
  • Blend strawberries with a little bit of orange juice and use as a refreshing coulis sauce.
  • Add strawberries to breakfast shakes to give them a more vibrant taste and texture.

WHFoods Recipes That Feature Strawberries

  • Strawberry Smoothie
  • 10 Minute Fresh Berry Dessert with Yogurt & Chocolate
  • 10-minute Kiwi Mandala
  • 10-Minute Strawberries with Chocolate Creme
  • Grapefruit Sunrise

Individual Concerns

Strawberries and Pesticide Residues

Virtually all municipal drinking water in the United States contains pesticide residues, and with the exception of organic foods, so do the majority of foods in the U.S. food supply. Even though pesticides are present in food at very small trace levels, their negative impact on health is well documented. The liver’s ability to process other toxins, the cells’ ability to produce energy, and the nerves’ ability to send messages can all be compromised by pesticide exposure. According to the Environmental Working Group’s 2013 report “Shopper’s Guide to Pesticides,” conventionally grown strawberries are among the top 12 fruits and vegetables on which pesticide residues have been most frequently found. Therefore, individuals wanting to avoid pesticide-associated health risks may want to avoid consumption of strawberries unless they are grown organically.

Strawberries and Oxalates

Strawberries are among a small number of foods that contain measurable amounts of oxalates, naturally-occurring substances found in plants, animals, and human beings. When oxalates become too concentrated in body fluids, they can crystallize and cause health problems. For this reason, individuals with already existing and untreated kidney or gallbladder problems may want to avoid eating strawberries. Laboratory studies have shown that oxalates may also interfere with absorption of calcium from the body. Yet, in every peer-reviewed research study we’ve seen, the ability of oxalates to lower calcium absorption is relatively small and definitely does not outweigh the ability of oxalate-containing foods to contribute calcium to the meal plan. If your digestive tract is healthy, and you do a good job of chewing and relaxing while you enjoy your meals, you will get significant benefits—including absorption of calcium—from calcium-rich foods plant foods that also contain oxalic acid. Ordinarily, a healthcare practitioner would not discourage a person focused on ensuring that they are meeting their calcium requirements from eating these nutrient-rich foods because of their oxalate content. For more on this subject, please see “Can you tell me what oxalates are and in which foods they can be found?”

Nutritional Profile

Strawberries provide an outstanding variety of phytonutrients, including anthocyanins (especially cyanindins and pelargonidins); flavonols (especially procyanidins, catechins, gallocatechins, epicatechins, epigallocatechins, kaempferol and quercetin); hydroxybenzoic acids (especially ellagic acid); hydroxycinnamic acids (including cinnamic, coumaric, caffeic, and ferulic acid); and stilbenes (including resveratrol). Strawberries are an excellent source of antioxidant-promoting vitamin C and manganese. They are also a very good source of heart-healthy folate, blood sugar-regulating dietary fiber and thryoid health-promoting iodine. Plus, strawberries are a good source of heart-healthy potassium, omega-3 fatty acids, magnesium, and vitamin K.

For an in-depth nutritional profile click here: Strawberries.

In-Depth Nutritional Profile

In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Strawberries is also available. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more.

Introduction to Food Rating System Chart

In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the nutrients for which this food is either an excellent, very good, or good source (below the chart you will find a table that explains these qualifications). If a nutrient is not listed in the chart, it does not necessarily mean that the food doesn’t contain it. It simply means that the nutrient is not provided in a sufficient amount or concentration to meet our rating criteria. (To view this food’s in-depth nutritional profile that includes values for dozens of nutrients – not just the ones rated as excellent, very good, or good – please use the link below the chart.) To read this chart accurately, you’ll need to glance up in the top left corner where you will find the name of the food and the serving size we used to calculate the food’s nutrient composition. This serving size will tell you how much of the food you need to eat to obtain the amount of nutrients found in the chart. Now, returning to the chart itself, you can look next to the nutrient name in order to find the nutrient amount it offers, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration’s “Reference Values for Nutrition Labeling.” Read more background information and details of our rating system.

Strawberries
1.00 cup
144.00 grams
46.08 calories
Nutrient Amount DV
(%)
Nutrient
Density
World’s Healthiest
Foods Rating
vitamin C 84.67 mg 141.1 55.1 excellent
manganese 0.56 mg 28.0 10.9 excellent
fiber 2.88 g 11.5 4.5 very good
folate 34.56 mcg 8.6 3.4 very good
iodine 12.96 mcg 8.6 3.4 very good
potassium 220.32 mg 6.3 2.5 good
magnesium 18.72 mg 4.7 1.8 good
vitamin K 3.17 mcg 4.0 1.5 good
omega-3 fats 0.09 g 3.8 1.5 good
World’s Healthiest
Foods Rating
Rule
excellent DV>=75% OR
Density>=7.6 AND DV>=10%
very good DV>=50% OR
Density>=3.4 AND DV>=5%
good DV>=25% OR
Density>=1.5 AND DV>=2.5%
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