Because of recent events, notably, the global COVID-19 pandemic, all kinds of immune support products have been front and center. You understand how probiotics are a highly effective tool to promote desirable immune function and resistance to potentially harmful bacteria and viral adhesion.
You may also know to take vitamin C and zinc to buttress the support provided by probiotics in ensuring proper immune function.
But berries are not only a source of nutrition to help support immune function, they also have several other key benefits for health and well-being, stemming from the collection of phytochemicals—some of which they all share, and others unique. They epitomize the oft-repeated assertion from Hippocrates: “Let food be thy medicine.” Let’s take a look at this immune arsenal from the Earth.
Elderberry: Perhaps best known as the natural cold-remedy syrup, elderberry remains the king of berries for immune support. Elderberries are dense sources of vitamin C, vitamin A, and B complex. They contain quercetin, kaempferol, rutin and phenolic acids. And like other berries, they contain flavonoids and anthocyanidins, which exert both antioxidant and immune-support actions.
Elderberries have been extensively studied for efficacy in reducing symptoms of the common rhinovirus (cold). One study looked at how elderberry impacted cold duration in intercontinental air travelers. The randomized, double-blind, placebo-controlled clinical trial gave 312 air passengers investigated a proprietary elderberry extract or placebo. Cold episodes, duration and symptoms were assessed from baseline (10 days before travel) and at four days post-travel. According to the researchers, those in the placebo group experienced longer duration of cold days: 117 versus 57. The the average symptom score during the cold days was also significantly higher in the placebo group, at 583 versus 247.
A landmark research project in 2009 utilized a specific assay technology to identify and characterize anti-viral compounds in elderberry. The elderberry extract was found to inhibit Human Influenza A infection in vitro and the researchers concluded that, “the H1N1 inhibition activities of the elderberry flavonoids compare favorably to the known anti-influenza activities of Oseltamivir.”
A 2009 randomized, placebo-controlled study found that the individuals in the elderberry group (four does of 175 mg daily) showed “significant improvement in most flu symptoms,” compared to no improvement of severity in the placebo group. Another randomized, double-blind, placebo-controlled study of 60 adults (aged 18 to 54) who all had flu-like symptoms for 48 hours or less took either placebo or 15 ml of elderberry syrup four times a day for five days. At the study’s end, the researchers found that the elderberry group experienced an average of four days quicker relief from symptoms than those in the placebo group.
Elderberries may also help support healthy glucose metabolism and insulin secretion. A mouse model study showed that a water extract of elderberry significantly heightened glucose transport and glycogenesis without added insulin. Another study concluded that elderberry extract can lower insulin resistance.
Blueberries: When we think of berries, blueberries are often the first to come to mind. These indigo fruits are distinguished in that they are the only fruit that is naturally blue. Blueberries are one of the highest providers of nutrients of all berries. One cup has 4 grams of fiber, 24% RDI of vitamin C, 36% RDI of vitamin K and 25% RDI of manganese. Several studies assert that blueberries have one of the highest antioxidant amounts of all common fruits and vegetables. Authors of one paper investigating the anthocyanin content in blueberries concluded, “consumption of blueberries, a food source with high in vitro antioxidant properties, is associated with a diet-induced increase in ex vivo serum antioxidant status.”
Blueberries can also protect DNA from being easily damaged, and in one study, has been shown to do just that when combined with apple juice. In this study, 168 people drank 34 ounces (1 liter) of a mixed blueberry and apple juice daily. After four weeks, the authors reported, oxidative DNA damage due to free radicals was reduced by 20%.
This study echoes a smaller study of 18 male volunteers who consumed either a blueberry drink or placebo daily for six weeks. The authors found that the combination of flavonols, phenolic acids and anthocyanins in the blueberries reduced markers of oxidative stress, and inflammation, as well as reduced levels of oxidized DNA bases and increased resistance to DNA damage via oxidation.
Just one serving of blueberries can get to work protecting your DNA. One research team assessed blood samples before and after ingestion of blueberries, at one, two and 24 hours. After one hour of eating the blueberries, there was an 18% reduction in DNA damage. The authors concluded that “one portion of blueberries seems sufficient to improve cell antioxidant defense against DNA damage.”
Too much oxidation in the body can also affect low-density lipoprotein (LDL); oxidized LDL increases risk of heart disease development. Here, antioxidants are invaluable, and antioxidants contained in fruits, such as berries and specifically blueberries can reduce the oxidation of LDL. In one study of obese individuals, a daily serving of 2 ounces of blueberries for eight weeks was found to reduce LDL oxidation by 27%. Blueberries can benefit overweight individuals in other ways, as well. One study found that obese individuals with a high risk of heart disease had a 4 to 6% decrease in blood pressure after consuming 2 ounces of blueberries per day for eight weeks.
Similar results were found in a study of 48 post-menopausal women who consumed 22 grams of freeze-dried blueberry powder daily for eight weeks. Compared to placebo, the women who consumed blueberry powder exhibited reduced blood pressure and arterial stiffness.
Raspberries: Not only do raspberries have a beautifully rich pink hue, they are bountiful in macronutrients and micronutrients: vitamin C, K and several Bs, manganese, magnesium, iron, copper, potassium and phosophorus. Animal studies have shown that raspberry consumption provides excellent antioxidant defense to bolster immunity, as well as manage inflammation.
Strawberries: The first real food crop that appears in spring in the Northeast, and are thus highly anticipated; strawberries are also an excellent source of antioxidants, chiefly ellagic acid, anthocyanins, catechins, quercetin and kaempferol. And according to one review, strawberry extracts have been shown to inhibit the pro-inflammatory COX enzymes.
Combination: Researchers from Harvard School of Public Health and Harvard Medical School studied the effects of consuming blueberries and strawberries from data pooled in the Nurses Health Study, which followed 93,600 women aged 25 to 42 for 18 years. They found that those women who ate the least amount of blueberries and strawberries had an increased risk of heart attack; conversely, those who ate the most were 34% less likely to have a heart attack. According to the researchers, the berries’ abundance of anthocyanins are known to relax blood vessels, which helps manage blood pressure. They also noted that those women who had lower risk of heart attack typically ate three or more servings of blueberries and/or strawberries each week. Yay, fruit salad!
As spring bursts forth, bringing an abundance of berries, it’s an exciting time to enjoy health and wellness from natural foods that not only taste good but support your overall immune function. Buy fresh and local, and look up the hundreds and hundreds of recipes online, from breakfasts and post-workout smoothies to desserts and salads. Buon appetito!