Recently scientists have enlisted top 50 foods as antioxidant sources from among commonly consumed foods in the United States and strawberries have got an exceptional ranking in the list. When the total antioxidant power was measured of all foods in uniform quantity (3.5 ounces or 100 g) strawberries grabbed the 27th rank among all the foods commonly eaten in the US. Moreover when only fruits were taken into consideration, strawberries were the 4th best, after blackberries, cranberries and raspberries. Nevertheless, as several foods (like seasonings and spies) are not commonly consumed in amounts as big as 100 g, scientists also considered common serving portions of all foods and their antioxidant capacity. In this type of evaluation, strawberries grabbed 3rd position among all US foods like fruits, vegetables, seasonings and spices, falling only behind blackberries and walnuts.
Strawberry may seem a commonplace food, but in terms of health-giving capacity, it is in no way common.
Strawberry – A Delicate Fruit
Food researchers have observed that strawberry is a very perishable, fragile and delicate fruit. A close look was taken at the storage temperature, storage time, storage humidity and level of ripeness of strawberries and it was found that there were significant differences between various kinds of strawberry storage.
On an average, it was seen that maximal time for storing strawberry was 2 days without considerable loss of vitamin C as well as polyphenol antioxidants. But strawberries don't become harmful or useless after 2 days of storage. But more the storage time, more is the nutritional loss.
Regarding humidity, 90% to 95% is found to be optimal. Most of the freezers will average a much less humidity i.e. from 80% to 90%. As air circulation inside the refrigerators can reduce humidity, you may wish to give strawberries more of storage humidity by storing them in the cold storage bins in your fridge (if they are available). If you don't have them, you can store strawberries in sealed containers in the fridge.
Optimal temperature for storing strawberries recommended by all public health organizations is 2° C (36° F).
When it is about ripeness, studies have shown that under-ripeness as well as over-ripeness can impact the phytonutrient content of strawberries significantly, particularly their antioxidants polyphenols. Luckily optimal ripeness of strawberries can be evaluated by color. Thus when strawberries are the most vibrant with their pinkish-red color, they are the most perfect to eat.
Strawberries for Improving Blood Sugar Regulation
Strawberries have long been the topic of interest of researchers for their capacity of blood sugar regulation.
However, the latest studies are the most fascinating regarding the connection between the consumption of strawberries and table sugar, and levels of blood sugar. As you might correctly guess, overly intake of table sugar (5-6 teaspoons at a serving) can led to an undesired spike in blood sugar. But you might not know that this spike can be reduced by simultaneous intake of strawberries! This is what scientists have found out. Further, they have hypothesized that polyphenols in strawberries have an important role in regulating blood sugar levels.
This makes wonderful news for healthy individuals as well as patients of type 2 diabetes who can enjoy fresh strawberries regularly without getting their blood sugar level increased.
Strawberries in Inflammation
With their fantastic composition of phytonutrients like ellagitannins, anthocyanins, terpenoids, flavonols and phenolic acids, strawberries have attracted researchers' attention regarding their inflammatory properties.
This beautiful fruit reduces the levels of inflammatory markers such as C-reactive protein (CRP) when eaten for many days per week in amounts like around 1 cup per day. Latest studies have revealed that many blood markers for unwanted chronic inflammation can get better because of regular consumption of strawberries. It's interesting to note that in a large-scale trial, strawberry consumption didn't offer anti-inflammatory benefits till the consumption was at least thrice every week.
As per the recommendations of CDC (Centers for Disease Control) regarding berries, e.g. strawberries, 8 large strawberries measure 1 cup. However your fruit goals need to be higher than the CDC recommended amounts of fruits, i.e. you should consume around 3 fruit servings every day to get optimum health benefits, and for berries you should include them at least three or four times in a week within your fruit intake.
Strawberries for Cardiovascular Health
Our heart and blood vessels require protection from inflammatory and oxidative damage and in that context, the anti-inflammatory and antioxidant profile of strawberries is exceptional.
Amongst all fruits considered to be the Healthiest Foods of the World, strawberries stand out as the best source of an essential vitamin – vitamin C in a number of nationwide researches conducted in various countries. A study surveyed 66 different fruits eaten by adults, showed that strawberries were not only the best source of vitamin C, but also a source that gave more than twice vitamin C as that given by all the fruits on an average.
Strawberries also ranked 3rd after raspberries and grapes as the best source of manganese in the list of World's Healthiest Foods. Manganese is taken to be an important antioxidant mineral, due to its major role as a cofactor in the antioxidant enzyme activity of SOD (superoxide dismutase).
But the antioxidant capacity of strawberries is mainly attributed to its phytonutrient content. Majority of the phytonutrients in strawberries act not only as antioxidants but even as anti-inflammatory elements. These are:
Anthocyanins (pelargonidins, canidins), flavonols (gallocatechins, catechins, procyanidins, quercetin, kaempferol), hydroxyl-benzoic acids (vanillic acid, gallic acid, salicylic acid, ellagic acid), hydroxyl-cinnamic acid (ferulic acid, caffeic acid, coumaric acid, cinnamic acid), tannins (gallotanins, ellagitannins), stilbenes (reservatrol)
Many studies have revealed that all these phytonutrients in strawberries work synergistically to offer cardiovascular benefits, including reduction in lipid peroxidation (oxidation of fats) in the cell membranes of blood vessels, reduction in levels of circulating fats, like LDL cholesterol and total cholesterol, and reduction in activity of ACE (angiotensin I-converting enzyme) an enzyme the over-activation of which increases the risk of high blood pressure. Amounts of strawberries consumed in most of these studies were 1 to 2 cups per day.
Strawberries Against Cancer
As chronic overly inflammation and oxidative stress are common factors in the formation of cancer, strawberries are definitely a topic of interest for studies regarding its cancer-reducing properties due to their unmatched anti-inflammatory and antioxidant nutrient content. Anticancer benefits of strawberries are best proven in case of esophageal, cervical, colon and breast cancers.
Most animal studies for inhibiting tumors have focused on strawberries' phytonutrient content. Amongst these, ellagitannins and ellagic acid in strawberries have newly found to be anticancer nutrients of special interest.
Though the chemo-preventive (anticancer) properties of these nutrients are yet to be entirely understood, their capability to reduce risk of some types of cancer may be connected to their power to accelerate the activity of antioxidant enzymes such as superoxide dismutase or catalase, their ability to reduce the activity of pro-inflammatory enzymes such as cyclo-oxygenase-2 (COX-2) or their power to reduce manifestation of the enzyme inducible iNOS (nitric oxide synthase).
Strawberries Imparting Other Health Benefits
Another major area of interest regarding the health benefits of strawberries is aging and age-related problems. Many primary studies on strawberry intake on aged animals have revealed improved cognitive function (including better recognition of objects) after ingestion of a diet containing 2% of the calories given by strawberry extracts. Improved motor function (better coordination of movements and balance) has been shown too in these studies with strawberry extracts.
Recovery in inflammatory bowel diseases, like Crohn's disease and ulcerative colitis, has also been found in the primary animal studies with the daily intake of strawberry powder or extract. It's interesting to note that although strawberries consist of comparatively low amounts of salicylic acid (an anti-inflammatory substance resembling to a great extent with acetylsalicylic acid in aspirin) some scientists are of opinion that this naturally present anti-inflammatory compound in strawberries might be partially responsible for reduced inflammation in the digestive tract of patients diagnosed with inflammatory bowel problems like Crohn's disease or ulcerative colitis.
Arthritis associated to inflammation (including rheumatoid arthritis) and eye diseases connected to inflammation (including macular degeneration) are two more areas wherein strawberries may prove to be important in offering health benefits.
Although studies in these areas are at a preliminary stage, the distinct combination of phytonutrients in strawberries will possibly explain some of the important health benefits of strawberries in these areas very soon.