WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
Studies have shown that your diet — or more specifically, having a high intake of antioxidants in your diet — plays a major role in helping to prevent the development of allergic diseases and allergy responses.
One study published in Clinical and Experimental Allergy in February 2017 found a significant inverse relationship between the total amount of antioxidants you eat and how sensitive you are to inhalant allergens, like pollen.1
Another study published in Allergy, Asthma & Immunology Research in March 2013 looked at the connection between an antioxidant-rich diet and the risk of allergic disease in Korean children between the ages of 6 and 12. Researchers found that children who ate more vitamin C, which has strong antioxidant activity, had fewer allergy symptoms.2
Black Raspberries Can Help Your Skin
While there’s existing research on the benefits of antioxidants in general, a July 2020 animal study published in Nutrients looked at how a specific food, black raspberries, may be able to combat skin inflammation associated with allergies.3
The researchers found that a diet high in black raspberries reduced inflammation from contact hypersensitivity, an allergic skin condition that causes redness, swelling and inflammation.
For the study, they separated mice into two groups — a control group and an intervention group. Both were fed the same diet, with one difference: The intervention group was also given the equivalent to one human serving of black raspberries.
After three weeks, the researchers exposed one ear on each mouse to an allergen that caused contact hypersensitivity and associated swelling. Over the next few days, they measured improvements in swelling to see if there was a difference between the two groups.
The found that in the mice that ate black raspberries, swelling reduced significantly more than in the control group. The researchers concluded that the antioxidant compounds in black raspberries help inhibit inflammation by acting on dendritic cells, which process antigens and tell the immune system to turn off or on, especially when it comes to inflammation.
According to Steve Oghumu, lead researcher for the study,4 when your skin is exposed to an allergen, like in the case of contact hypersensitivity, your immune system sends out cells that turn on inflammation and cause itchiness, redness and swelling.
Oghumu adds that instead of trying to treat the response after the fact with steroid creams and other potentially harmful topicals, you may be able to control or reduce the severity of the response by eating black raspberries and other foods that are high in anthocyanins and antioxidant compounds.
Other researchers speculate that antioxidants can also help in a different way that’s connected with oxidative stress and the damage it can cause to your cells. According to the study in Allergy, Asthma & Immunology Research,5 a lack of antioxidants in the diet allows an increase in oxidative stress, which can trigger allergic responses that are inflammatory in nature.
On the other hand, a high intake of antioxidants helps prevent the formation of free radicals, which can cause lipid peroxidation, or the breakdown of lipids, and, ultimately, damage to your cell membranes or DNA. Both of these things contribute to reduced sensitivity to allergens and irritants.
Other Health Benefits of Black Raspberries
In addition to helping reduce inflammation associated with skin allergies, black raspberries have been shown to:6
- Reduce eyestrain
- Improve night vision
- Help prevent macular degeneration
- Protect against DNA damage
- Prevent cancer
Black raspberries are also rich in ellagic acid,7 an antioxidant phenol that has been shown to decrease the symptoms of chronic metabolic diseases, like insulin resistance, Type 2 diabetes, nonalcoholic fatty liver disease and dyslipidemia.8
The ellagic acid in black raspberries has also been shown to help combat obesity by increasing thermogenesis and turning white fat into brown fat.9 White fat stores energy and is a main contributor to obesity, while brown fat dissipates energy in the form of heat and may actually help increase energy expenditure or the number of calories you burn.10
Black Raspberries Are Different Than Blackberries
Although black raspberries look similar to blackberries, there are some distinct — albeit small — differences in their appearance. As the name implies, black raspberries are darker than red ones, but they are similar in size and covered with fine hairs. Also, like regular red raspberries, black raspberries are hollow in the center. On the other hand, blackberries are large with bigger cells and have a white, dense core.
Red and black raspberries and blackberries are all high in anthocyanins, flavonols, phenolic acid, ellagitannins, vitamin C, vitamin E and folic acid — compounds that exhibit antioxidant activity. But black raspberries are particularly high in the plant pigments and have an overall higher total phenolic count.11
According to a 2015 research article in Open Chemistry, black raspberries contain a significantly higher number of anthocyanins than both red raspberries and blackberries and, because of this, they have a much higher antioxidant capacity.12
It’s this antioxidant capacity that’s responsible for many of the health benefits connected to black raspberries, including their ability to fight inflammation associated with skin allergies.
Health Benefits of Red Raspberries
Red raspberries may not be as high in anthocyanins and other antioxidant compounds as black raspberries or blackberries, but they’re still a powerful health promoter.
Red raspberries are high in vitamin C, quercetin and gallic acid,13 antioxidants that contribute to their ability to fight heart disease, circulatory disease, age-related decline and cancer. Raspberry oil has a sun protective factor and may protect against wrinkles.
Also high in ellagic acid, red raspberries may efficiently help stop damage to cell membranes. In combination with other flavonoid molecules found in red raspberries, this unique blend of antioxidants also has some antimicrobial properties.14
The high nutrient value of the berries also boosts your immune system and helps you fight off disease. When grown in fertile, healthy soil, they are an excellent source of manganese and vitamin C, helping to protect against oxygen-related damage.
The combination of flavonoids and antioxidants in berries have demonstrated in animal studies that they may help with memory improvement15 and may protect against cognitive decline.16 The fiber and water content in the berries, including black raspberries, may also help prevent constipation.
How to Grow Your Own Berries
While berries are worth their weight in gold when it comes to nutrition, buying them in small containers at your local grocery store can get pretty costly. The good news is that raspberries are fairly easy to grow in your own backyard. Growing your own berries also ensures they aren’t sprayed with fungicides or insecticides that can be detrimental to your health.
If you want to grow your own berries, choose a well-drained location that isn’t soggy and has access to full or partial sun. If you live in a hotter climate, choose a location that has sun in the morning, but gets plenty of afternoon shade.17 If you’re planting multiple bushes, which isn’t required since black raspberries are self-pollinating, make sure they’re at least 2.5 feet apart.
Water plants about once per week before you see any fruit, soaking the ground instead of wetting the foliage directly.18 Once fruit develops, the black raspberries need 1 to 1.5 inches of water every week. If you don’t adequately water the berries during this time, you’ll end up with small berries that have a lot of seeds.
Black raspberries do have a short season that begins in early July and lasts about two to three weeks,19 so you want to make sure you’re timing your harvesting to reap the most from your efforts. If you can’t finish all of the black raspberries, pick them and freeze them in BPA-free containers to use later in smoothies or for homemade dairy-free sorbet.