Berries As Nature’s #1 Antioxidant Food
Dr. Paul Gross
Dark berries like blueberries and cranberries are increasingly
recognized in the public as health icons. Berries are not only nutritious
by their contents of vitamins, minerals, amino acids, protein
and dietary fiber, berries are also synonymous with antioxidant
health benefits.
Antioxidants are an important nutrient category thought to be
the major health characteristic of colorful fruits and
vegetables. Antioxidants are substances synthesized in our
bodies or obtained via edible plant chemicals that can prevent
or slow oxidative stress to our body’s cells. More than 60
diseases, including cancer, diabetes, inflammatory,
neurological and cardiovascular diseases, are linked to
oxidative stress that may be relieved by dietary antioxidants.
Scientists believe that plants make antioxidant chemicals to
protect the plant’s regenerative capacity from the damaging
effects of constant exposure to sunlight, ultraviolet
radiation, infections, pests, injury and oxygen radicals
produced during photosynthesis. These antioxidants are found
in their highest concentrations in the fruit skin (or rind) and
seeds.
Antioxidant phytochemicals, such as the blueberry anthocyanins,
contribute scent and blue pigment to the berry skin. This plays
a useful regenerative role to attract insect pollinators and
birds that eat the fruit and then disperse the seeds in their
droppings.
Plants also benefit from antioxidant protection in their skin
against ultraviolet radiation, photo-oxidative processes, and
viral or bacterial pathogens. These are benefits that can be
passed on to animals and humans who consume the berries.
Oxidative Stress and “Pigment Power”
Without protective antioxidants from pigments like anthocyanins
in berry skin, reactive oxygen species (ROS) are created during
normal photosynthesis leading to oxidative injury. These
injuries affect proteins, lipids and nucleic acids, and can
cause alteration in gene transcription and even lead to
programmed cell death (a process scientists call “apoptosis”,
eh-poh-toe-sis) in the fruit or its seeds. Some botanists and
food chemists refer to this protective benefit as “pigment
power”, which is desirable to obtain through the human diet. We
acquire this transfer of protection by eating fruits, vegetables
and animal sources that have color-rich pigments. Dark berries
are an excellent source of these pigments.
Within colorful berries we can find many members of the pigment
group called “phenolics.” Each member provides antioxidants,
color, scent, and flavor qualities. The following is just a
sampling of the thousands of edible plant phenolics. Any one
berry species may contain dozens of antioxidant pigments. Each
of the berries below is a rich source of anthocyanin pigments;
a few of which are listed where medical and food science have
revealed preliminary evidence for health benefits.
Here is a list of the antioxidants found in the following
berries:
o Blackberries: gallic acid
o Black raspberries: ferulic acid
o Blueberries: anthocyanins, chlorogenic acid, peonidins
o Cranberries: proanthocyanidins, catechins, quercetin
o Elderberries: myricetin
o Red raspberries : ellagitannins, procyanidins
o Red grapes: resveratrol, proanthocyanidins (seeds), catechins
o Strawberries: ellagic acid
ROS – Radical Oxygen Species
When human cells use oxygen, they naturally produce ROS as
by-products of normal metabolism. This can lead to cell damage
if normal counter-balances are absent in the environment inside
and around cells. ROS are also called “oxygen free radicals” or
elements so reactive they are “free” to interact with numerous
cells and chemicals in the body, often in a way that is
damaging.
Antioxidants synthesized internally or introduced from our
diets act as neutralizing sponges or "scavengers" of ROS. By
donating electrons sought by the free radical, antioxidant
molecules serve to counterbalance, absorb, quench, prevent or
repair damage done by ROS.
However, when balancing mechanisms are ineffective, perhaps
because of a diet poor in antioxidant foods or during the
decline of body functions with disease or aging, ROS disperse
randomly in a concentration gradient from their point of
formation. There, if unchecked by antioxidants, they can cause
damage within cells and to nearby cells, that can contribute to
disease and aging. This is one of the leading theories for how
Alzheimer’s disease progressively destroys neurons.
Oxidative Stress and Dietary “Therapy”
Most diseases are initiated and perpetuated to some degree by
ROS and by insufficient amounts of internal and dietary
antioxidants. These are the underlying conditions for
“oxidative stress” which may explain a sizable component of
aging.
If chronic, oxidative stress can lead to an increased risk of
developing the following diseases:
• Cancer
• Cardiovascular and inflammatory disorders
• Diabetes
• Neuronal degeneration (e.g., Alzheimer’s and Parkinson’s
disease)
• Macular degeneration causing vision loss and general
deterioration of aging
• Chronic sickness
Measuring Antioxidant Strength: ORAC
The term ORAC, standing for “oxygen radical absorbance
capacity”, is a numerical way of representing antioxidant
strength in berries and other foods. When antioxidants are
present in a food, their collective strength can be measured in
the test tube assay called ORAC.
Recently, scientists working with the US Department of
Agriculture published a database of ORAC values.
Dark berries, especially wild and cultivated blueberries,
blackberries and cranberries, stood out with the highest ORAC
values among some 25 fruits tested. Their values were in a
range of about 7,000-13,000 ORAC units per Cup or 250 ml
serving.
Preliminary North American guidelines recommend at least 5,000
ORAC units per day for the adult diet. Doubling that number
would not only be safe for antioxidant reserves, but would also
provide antioxidant qualities that would supply numerous
essential macro- and micronutrients. Most importantly though,
it would make for enjoyable eating!
The ORAC test will likely gain public acceptance as a standard
measure allowing comparisons of freshness and antioxidant
strength in different foods. This standard will facilitate
selection of high ORAC foods and relate antioxidant capacity to
potential protection of health. For example, there is already
scientific evidence for an inverse correlation between dietary
intake of antioxidant foods and incidence of some cancers (US
National Cancer Institute).
Antioxidant Berries
Wild Blueberry (Vaccinium angustifolium).
Wild lowbush blueberries have nearly 50% greater antioxidant
strength than their cultivated cousins – the highbush blueberry
– that is so popular in grocery stores. Wild blueberries score
highest in ORAC among common (but not all) berries, having
about 13,000 ORAC units per Cup or 250 ml. Over the past 10
years, the focus of food scientists on health properties of
wild blueberries has revealed a compelling story of nutrient
richness and diversity of potential health benefits, including:
• Urinary tract health (identical in strength to cranberries)
• Inhibition of cancer development
• Cardiovascular protection
• Mental alertness
• Vision support
Blackberry (Rubus ursinus)
The juicy delicious dark blackberry has great taste and
nutrient richness. Confirming the idea that the darkest berries
correlate with the strongest antioxidant activity, science has
recently demonstrated that blackberries have some of the
densest concentrations and widest diversity of phenolics found
in the plant world. Blackberry’s ORAC is nearly 8000 units per
Cup or 250 ml.
Black raspberry (Rubus occidentalis)
“Blackcaps” are a little-known powerhouse of antioxidant
richness and outstanding taste. Isolates from black raspberries
were shown in laboratory tests to specifically starve tumor
cells by preventing growth of new tumor blood vessels. Overall
a more powerful antioxidant berry than even the wild blueberry
(ORAC > 15,000 per Cup or 250 ml), blackcaps contain a toolkit
of flavors and nutrients.
Cranberry (Vaccinium macrocarpon)
The North American cranberry has become famous for its popular
juice. Known well for its anti-adhesion properties, which
inhibit bacterial infections in the urinary tract, cranberry
extracts have shown anti-cancer and cardio-protective effects
in laboratory studies. These results occur mainly from the
cranberry’s abundant supply of antioxidant phenolics that also
make it a promising agent for blood, brain and vision health.
Elderberry (Sambucus nigra)
Another phenolic-rich dark berry with a delectable taste, the
elderberry has been associated with many of the potential
health benefits already mentioned. It has stood out
particularly in laboratory tests for its anti-inflammatory and
urinary tract benefits. The elderberry also shows promise for
anti-bacterial and anti-viral effects that may offer protection
against such virulent pathogens as Salmonella, E. coli, H.
pylori and Staphylococcus.
Red Raspberry (Rubus idaeus)
The red raspberry is well loved for its subtle distinct flavor
but is also a wonderful store of antioxidant phytochemicals,
particularly one called ellagic acid. One of its other
constituents, a ketone, was shown in recent laboratory studies
to stimulate fat metabolism, causing experimental animals to
lose significant weight.
Red Grape (Vitus vinifera)
The red grape is valued for its familiar popular taste and
diverse number of phenolics residing mainly in its skin and
seeds. Especially rich in the phenolic called resveratrol, a
powerful antioxidant, red grapes are linked to having a
possible beneficial effect on:
• Alzheimer’s disease
• Heart disease
• Cancer
• Osteoarthritis
• Other aging disorders
Strawberry (Fragaria vesca)
Containing a host of antioxidant phenolics, the strawberry’s
constituents may be particularly important as natural
blood-thinners, anti-fungal agents and inhibitors of oxidizing
effects on cells from chronic stress.
Other Antioxidants
Other phenolic antioxidants mentioned in current public media
include:
• Apigenin
• P-coumarin
• Kaempferol
• Caffeic acid
• Hydroxycinnamic acid
• Tannic acid
• Salicylic acid (similar to aspirin)
These pigment chemicals belong to the flavonoid subclass of the
phenolic super-family and are present among dark berries.
Color-rich plant foods like berries offer a delicious,
nutritious way of keeping dietary intake of antioxidants high.
Eat color! Gain ORAC! Live Well!
Reading
* PubMed, US National Library of Medicine, http://pubmed.gov
* Wild Blueberry Association of North America,
http://www.wbana.org
* Wu X et al., Lipophilic and hydrophilic antioxidant
capacities of common foods in the United States. J Agric Food
Chem 52:4026-37, 2004.
Copyright 2006 Berry Health Inc.
About The Author: Dr. Paul Gross is a scientist and expert on
cardiovascular and brain physiology. A published researcher,
Gross recently completed a book on the Chinese wolfberry and
has begun another on antioxidant berries. Gross is founder of
Berry Health Inc, a developer of nutritional, berry-based
supplements. For more information, visit
http://www.berrywiseonline.com
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