Strawberries. Health benefits and risks from consuming them

The strawberry, scientifically known as Fragaria ananassa, is a hybrid of two wild strawberry species from North America and Chile. The strawberries have a bright red color, a juicy texture, a characteristic aroma, and a sweet taste.

They are an excellent source of vitamin C and manganese and also contain significant amounts of folic acid (vitamin B9) and potassium. Strawberries are very rich in antioxidants and phytochemicals and have significant benefits for heart health and blood sugar control.

They are usually eaten raw and fresh, but can also be used in jams, jellies, desserts, and food flavors.

Nutrients

Strawberries consist mainly of water (91%) and carbohydrates (7.7%). They contain only small amounts of fat (0.3%) and protein (0.7%). One cup of strawberries (150 grams) contains less than 50 calories.

The following table contains information on the most important nutrients of strawberries.

Carbohydrates

Fresh strawberries have a very high water content, so their total concentration of carbohydrates is very low (less than 12 grams of carbohydrates per cup). Most of the carbohydrates come from simple sugars, such as glucose, fructose, and sucrose, but they also contain a significant amount of fiber.

The net carbohydrate content is less than 6 grams for every 100 grams of strawberry. Strawberries have a glycemic index of 40, which is relatively low. This means that strawberries do not raise blood sugar levels quickly and at high values and are considered safe for diabetics.

Fiber

About 26% of the carbohydrates in strawberries are in the form of fiber. One cup of strawberries provides 3 grams of fiber, both soluble and insoluble. Fiber is important for the nutrition of friendly bacteria in the intestine (intestinal microbiome) and for the improvement of the health of the digestive system. They are also useful for weight loss and can prevent many diseases.

Vitamins and trace elements

The most important vitamins and minerals in strawberries are:

• Vitamin C: Strawberries are an excellent source of vitamin C, a very important antioxidant for the immune system and skin health.
• Folic acid (Vitamin B9): One of the vitamins of the B complex, important for the normal growth of tissues and cell function. Folic acid is especially important for pregnant women and the elderly.
• Manganese: Manganese is found in large quantities in whole grains, legumes, fruits, and vegetables and is an important trace element for many normal processes in the body.
• Potassium: Potassium is an element that is involved in many normal functions of the body, such as regulating blood pressure.

To a lesser extent, strawberries also contain iron, copper, magnesium, phosphorus, vitamin B6, vitamin K, and vitamin E.

Phytochemicals

Strawberries are full of antioxidants and very beneficial phytochemicals.

• Pelargonidin: It is the main anthocyanin in strawberries, responsible for their color.
• Ellagic acid: Ellagic acid is an antioxidant polyphenol, found in high amounts in strawberries, and can have many health benefits.
• Ellagitannins: Ellagitannins are plant compounds that are converted to ellagic acid in the gut.
• Procyanidins: Procyanidins are powerful antioxidants found in the flesh and seeds of the strawberry and have beneficial effects on health.

Anthocyanins

More than 25 different anthocyanins have been found in strawberries. Pelargonidin is the most abundant. Anthocyanins are responsible for the bright colors of fruits and flowers. They are usually concentrated in the peel of fruits, but strawberries also have anthocyanins in their flesh.

The anthocyanin content is usually proportional to the intensity of the color and significantly increases with the ripening of the fruit.

Eating foods rich in anthocyanins has been associated with numerous health benefits, especially for heart health.

Ellagitannins and Ellagic acid

Strawberries are consistently ranked among the top sources of phenolic antioxidants, with levels 2 to 11 times higher than other fruits. Ellagitannins and ellagic acid are a large part of these antioxidants in strawberries.

Phenolic antioxidants have been associated with numerous health benefits including the fight against bacterial infections and the prevention of cancer. The main ellagitannin in strawberries is called sanguiin H-6.

Health benefits of eating strawberries

Fruit consumption has been linked to a reduced risk of many chronic diseases. Eating strawberries can improve heart health, lower blood sugar levels and help prevent cancer.

Strawberries and heart health

Cardiovascular disease is the most common cause of death worldwide. Many studies have found a link between eating strawberries (and similar fruits such as blueberries) or the anthocyanins derived from these fruits and improving cardiovascular health. Large studies involving thousands of people have linked the consumption of raspberries to a lower risk of heart-related deaths.

According to a study of middle-aged people, blueberries and strawberries were able to increase HDL cholesterol, lower blood pressure and improve platelet function.

Strawberries can also improve the state of antioxidants in the blood, reduce oxidative stress, inhibit chronic inflammation, improve vascular function, improve the profile of blood lipids and reduce the extremely harmful oxidation of LDL cholesterol.

Recently, the effects of freeze-dried strawberries on type 2 diabetes and metabolic syndrome, mainly in overweight or obese individuals, have been studied. After 4-12 weeks of taking this supplement, a significant reduction in many important risk factors such as LDL-cholesterol, inflammatory markers (CRP), and oxidized LDL was observed.

Strawberries can reduce the risk of heart disease by improving the profile of blood lipids, lowering blood pressure, and reducing inflammation and oxidative stress.

Strawberries and sugar regulation

When carbohydrates are digested, they are broken down into simple sugars, which are then released into the bloodstream. When blood sugar levels rise, the body begins to secrete insulin, which contributes to the entrance of glucose from the bloodstream into the cells in order to be used for energy production or storage. Imbalances in the regulation of blood sugar or diets that lead to large increases in blood sugar are associated with an increased risk of obesity, type 2 diabetes, and cardiovascular disease.

Strawberries can slow down the digestion of carbohydrates and reduce large postprandial increases in both blood sugar and insulin levels.

Strawberries and cancer prevention

Cancer is a serious disease, characterized by the uncontrolled growth of abnormal cells. The onset and progression of cancer are often associated with oxidative stress and chronic inflammation. Some studies show that fruits such as blueberries and strawberries can help prevent several types of cancer through their ability to fight oxidative stress and inflammation.

Strawberries have been shown to inhibit tumor formation in experimental animals (oral cancer) and human liver cancer cells. The protective effects of strawberries may be due to ellagic acid and ellagitannins, which have been shown to inhibit the growth of cancer cells.

More research is needed to understand the full mechanism and impact of strawberry consumption on cancer. However, both in vitro and in animal studies are very encouraging.

Side effects

Strawberries are usually well-tolerated, but strawberry allergy is quite common. Strawberries grown in protected environments (such as greenhouses) may contain more pesticide residues than strawberries grown outdoors.

Allergy to strawberries

Strawberry allergy is quite common, especially in young children. Strawberries contain a protein that can cross-react and cause symptoms in people who are sensitive to birch pollen or apples. Allergy-causing proteins are thought to be linked to red anthocyanins. Colorless, white strawberries are usually well tolerated by allergic individuals.

Common symptoms of an immediate allergic reaction include itching, hives, headache, swelling of the lips, face, and tongue, or breathing problems in severe cases.

Food intolerance to strawberries

The Rosaceae family of berries includes Strawberry, Raspberry, Boysenberry, White Rasberry, and many other species and hybrids that are collectively characterized as Forest Fruits (or berries from a bush), Wild Rose, and Rose. Strawberry ⁽⁷⁹⁾ (Fragaria x ananasa) is the most famous hybrid of strawberry grown almost all over the world. There are still several species and varieties of strawberries.

Strawberry is eaten raw as a fruit, in jams, juices, ice creams, candies, chewing gums, sorbets, chocolates, compotes, pies, and many other sweets. Apart from being fresh, the strawberry can be frozen and dried and in this form, it is found in muesli and breakfast cereals, in cereal bars, etc. Strawberries are often used to flavor dairy products such as yogurt, ice cream, milk, milkshakes, etc. Strawberry is used in many sweets, savory dishes, salads, juices, cocktails, and liqueurs. The wild strawberry (Fragaria vesca) is the ancestor of today's cultivated strawberry. Its fruits are small, very fragrant, and usually grow in forests. It has the same uses as the cultivated strawberry. Strawberry is a very common allergen. Strawberry leaves are eaten raw or cooked and used as a substitute for tea, while its root is used as a substitute for coffee in India. Strawberry is also used in traditional medicine (herbal medicine).

The following allergens have been isolated and characterized in F. ananassa: Fra a 1, Fra a 3, Fra a 4. Different varieties of strawberry may have different compositions to allergens, with the allergenic content always being lower in the white varieties in relation to red strawberry varieties. Cross-reactions between different species of the Rosaceae family (almond, apple, apricot, etc.) are possible and may be more intense between species and varieties within the genus Fragaria. Strawberry contains a variety of aromatic and vasoactive substances, e.g. histamine, which may lead to hypersensitivity reactions.

Food intolerance to strawberries (Code 79) can be tested with Trophoscan® 40+, 100 (Mediterranean), 200, 300, and 400 as well as Trophoscan® Asian, Vegetarian, and Kids. Strawberry antigens have been isolated without prior heat treatment* of the antigens.

Diagnostiki Athinon's TrophoScan® is the most valid, reliable, and effective way to test food intolerances, by measuring the levels of total IgG antibodies in the blood against potentially allergenic foods. The presence of these antibodies has been associated with diseases of the gastrointestinal tract (irritable bowel, celiac disease, and other disorders), migraines and other neurological disorders, disorders of the immune system (autoimmune diseases, susceptibility to infections, etc.), obesity and weight loss difficulty, skin diseases, chronic fatigue syndrome, arthralgias, and other chronic diseases.

TrophoScan® has been designed and created entirely by Diagnostiki Athinon. The food antigens used for the test have come from Greek products and from products that we can find and consume in the Greek market. Various studies have shown that there is a difference in the antigenic composition of food depending on the variety of food. Even the maturity of a fruit or vegetable can play a role in the antigenic composition.

*The heat treatment of antigens we use in Diagnostiki Athinon before the isolation of the antigens is a unique process before the beginning of the process of isolation of food proteins. It is made in foods that are commonly cooked (e.g., meat, poultry, fish) and undergo a thermal laboratory preparation equivalent to cooking, so that their antigenicity is even closer to the actual antigenic structure of the food we consume.

Antigens isolated in this way have been proven to be more effective (making the ELISA system much more sensitive) in recognizing and binding antibodies of all classes (IgA, IgG, IgE, IgM). Only TrophoScan® test of food intolerance across Europe uses this approach to the investigation of Food Intolerance. Food processing results in the formation of neo-allergens.