Picking Through the Latest Science on Berries and Health Benefits
Sharon Palmer, R.D.
Health Benefits of Berries
The health halo that crowns berries--the original "superfruit"--hasn't slipped a bit over the years. Ever since it was discovered that berries have very high total antioxidant capacity, the public has had a veritable love fest with berries, making them its favorite fruit.
Of all fruits, consumer research finds strawberries the favorite among adults and kids. Over the past decade, multiple research findings have supported the health benefits of berries, showing that they have a profound impact on chronic diseases, such as cancer, cardiovascular disease, diabetes and age-related mental decline.
In botanical terms, a berry is a fleshy fruit in which the entire plant ovary wall ripens into a soft fruit surrounding seeds. Thus the definition of berries extends to include fruits like tomatoes, grapes and avocados. But in common terms, "berries" refers to the small fruits with multiple seeds we're familiar with today.
While exotic berries such as acai have gleaned a lot of public attention, the largest body of berry research focuses on the traditional berries available in
Berry special origins
Berries intrigue scientists because they have an important role in ecology.
As in humans, bird vision is trichromatic (three primary colors are distinguished), which allows birds to spot colorful berries on a green bush. Some birds trade their bug diets for berries right before the enormous physical demands of migration, and bears tend to load up on berries prior to hibernation. Native American customs are rife with an appreciation for berries. They were used in important dishes such as pemmican (buffalo, fat and wild berries) and some tribes called berries "moqui," which meant "spirits of the ancestors."
Berries have been an important part of culinary traditions--from preserving berries to pressing them for juice--that stretch across many cultures and date back centuries. Could it be that berries offer particular benefits for humans that extend beyond just a delicious food?
Berries are low in calories, sodium and fat, and high in fiber, potassium and vitamin C. This profile makes them a perfect food for supporting heart health, normal blood pressure and weight loss. But that's not all, according to Seeram.
"It goes beyond their fiber, vitamin and mineral content," Seeram notes. "Berries are really packed with antioxidants. Plants put their best compounds on their outer layers and in seeds. A plant can't get up and put sunscreen on to protect itself from environmental damage. You eat it all with berries; they're loaded with skins and seeds and you don't even realize it. These berries are colored by pigments known as anthocyanins. These compounds make blueberries blue and strawberries red."
Gathering berry research from around the world
Leading international berry scientists gathered in
Scientists are trying to determine which bioactive ingredients are responsible for berry benefits. Researchers from
Dr. Seeram, who served as chairman for a symposium session, explains that within the class of polyphenols there are flavonoids such as anthocyanins, and procyanidins and ellagitannins. These compounds appear to be at the root of the protective effects of berries.
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Bioavailability is the buzz word
These days, just about every plant food has bragged about being on the high ORAC (oxygen radical absorbance capacity, a measure of antioxidant capacity) list. But many scientists don't put a lot of faith in ORAC values alone.
"It's a common marketing ploy to talk about how much antioxidant potential a food has, but it's misleading. These are lab-based tests; we don't know if it means anything in the body. The focus of research has moved away from total antioxidant capacity to what happens in live systems," reports Seeram.
Scientists are trying to determine what happens to these bioactive compounds when they are eaten. What gets into the blood and tissues? What happens when the liver enzymes and the gut microflora go to work on them?
Little research has been done on the bioavailability of berry compounds, but some new findings were presented at the symposium.
These findings give scientists a clue that after berries are consumed, some compounds are absorbed into body tissues, rather than being excreted by the body.
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BERRIES, DISEASE BUSTERS
Scientists can trace several ways that berries can mediate disease, such as targeting oxidative stress, inflammation, immune function and metabolism.
"Berry compounds work on multiple mechanisms in the body. They are hitting the pro-inflammatory processes and the central pathways linked with diseases like cancer, cardiovascular disease and Alzheimer's disease," notes Seeram.
While scientists continue to learn more about how berry compounds work in humans, Seeram says there are some facts you can take to the bank.
"Berries are healthy. Cranberries can prevent urinary tract infections, blueberries are important in brain health and berry compounds target pro-inflammatory pathways," Seeram notes. Another fact you can take to the bank? Berries are delicious. Try fitting them into your diet every day.
THE RECENT SCIENCE ON BERRY HEALTH
Researchers at the Berry Health Symposium reported a number of recent findings on how berries can fight disease, including:
--Strawberries prevented a rise in LDL oxidation (a cardiovascular disease risk factor) in overweight adults when eaten after a moderately high-fat breakfast.
--Topical black raspberry extract decreased skin cancer tumor number and size in rats exposed to ultraviolet B rays for 25 weeks.
--Berry anthocyanidins caused different methods of cell death in different kinds of tumor cells.
--Strawberry and blueberry supplementation protected rats from radiation-induced deficits in cognition.
--Cranberries can prevent bacterial adhesion in the urinary tract and stomach and oral cavity.
--Highbush blueberry (a common blueberry variety) protected retinal activity in rats after they received stress from light-induced retinopathy.
To read more about the scientific findings presented at the Berry Health Symposium, visit www.berryhealth.org.
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