When Lipton, M&M Mars and Kellogg are promoting the antioxidant
benefits of their products, you realize the big picture promise of these free
radical fighters has entered the public imagination. What is behind the surge of
interest—from consumers to the government to scientific institutions—in
these nutritional compounds?
Wayne G. Geilman, Ph.D., senior research scientist, Pure Fruit Technologies,
suggested the main draw is the fact that scientists have connected free radicals
to so many degenerative biologic functions. “This knowledge, combined with the
increase in the median age, has fueled interest in antioxidants,” he said.
“This population wants to enjoy life to the fullest and is willing to combat
the effects of aging on all fronts. Antioxidants are becoming the weapon of
choice to do this. Although consumers may not be able to interpret all the
scientific jargon concerning how antioxidants work, they have the feeling that
they do work, that they are generally safe and that they can be part of a proper
diet.”
As retailers of natural products, it’s a positive that there is a dawning
awareness about the potential of antioxidants for consumers. However, to be able
to market products effectively and steer consumers toward the right products for
their needs, it helps to understand some of the physiological basics of
antioxidants.
The bottom line is these powerful compounds stop a potential cascade of
cellular-level damage caused by free radicals, highly reactive molecules
featuring an unpaired electron in their outer shell. To stabilize themselves,
they steal an electron from a nearby molecule. Losing an electron to a free
radical can turn the victim into a radical, creating the potential for cascading
damage to healthy cells.
“There are both internally and externally generated sources of free
radicals,” noted Beeta Little, director of product development and technical
services, Bluebonnet Nutrition Corp. “Some of the internally generated sources
are energy production, byproducts from energy metabolism, reactions involving
transition metals such as iron, exercise and inflammation. Externally generated
sources include cigarette smoke, environmental pollutants, radiation,
ultraviolet light, certain drugs, ozone and alcohol.”
Oxidants
can damage cells by starting chemical chain reactions, or by damaging DNA at the
cellular level. “Our DNA is the blueprint for life,” said Cheryl Myers,
director of product development, Enzymatic Therapy. “If the blueprint is
damaged, you have problems when the cell goes to recreate itself. Either it ’s
not as efficient or you have mutations in the cell. So preventing that DNA
damage is critical to managing all aspects of the degeneration process in our
bodies.”
Fortunately, plants and animals have developed mechanisms to fight oxidative
damage by manufacturing antioxidant compounds within the body (endogenous
generation); unfortunately, levels of these fighters decline with age, making
ingestion of exogenous antioxidants increasingly important to maintain the
body’s integrity.
“Young people generally make lots of antioxidants naturally, but middle age
often signals a decline in antioxidants made by the body,” said Brant Herman,
Pomology. “Supplements can support the body’s production and maintenance of
maximum levels of these essential antioxidants.”
One of the body’s own protective mechanisms is the enzyme glutathione
peroxidase (GPx), which targets lipid hydroperoxide and hydrogen peroxide.
Increasing fruit and vegetable intake can improve production of GPx.1
Supplemental selenium can also bolster the activity of the
selenium-containing GPx.2
The body also creates superoxide dismutase (SOD), an enzyme that
targets superoxide, breaking it down to hydrogen peroxide and oxygen. Superoxide
is used in a positive way by the immune system to squash microscopic pathogens,
but can also inactivate those enzymes that control free iron, which can lead to
formation of hydroxyl free radicals. SOD supplementation (as GliSODin®, from
P.L. Thomas & Co.) may protect DNA from oxidative damage,3 and
increase blood antioxidant activity and status.4
Beyond the internal defenses, nature has provided thousands of powerful
antioxidant compounds in the foods we eat; these antioxidants can be broadly
classified as water-soluble (hydrophilic) and fat-soluble (lipophilic). In
general, water-soluble antioxidants react with oxidants in the cell cytoplasm
and plasma, while lipid-soluble antioxidants protect cell membranes from lipid
peroxidation.
“Since our bodies contain both water-soluble and fat-soluble compartments,
we need to have both kinds of antioxidants,” said Angelica Vrablic, Ph.D.,
nutrition research manager, American Health®. “Antioxidant formulations
should cover both water-soluble and fat-soluble antioxidants along with other
effective plant-based ingredients such as bioflavonoids or anthocyanins.”
Several essential nutrients count antioxidant activity among their benefits. Vitamin
C, one of the best known antioxidants, is a water-soluble compound with
promising protective activity against oxidation in brain tissue and the eyes,5,6
and acts as a foil for oxidative stress relative to cardiovascular disease
(CVD).7 Marci Clow, senior director of product research, Rainbow
Light Nutritional Systems, added: “Vitamin C protects our bodies from the
effects of pollutants by joining with oxygen and enzymes to convert toxic
substances into non-toxic derivatives excreted in the urine. It’s a good idea
to take a vitamin C formula that includes bioflavonoids because they may
increase vitamin C’s activity, as well as providing antioxidant protection of
their own.”
Vitamin E, the collective name for a set of eight related tocopherols
and tocotrienols, are fat-soluble antioxidants. Alpha-tocopherol has been the
most studied form, although all the isomers are considered critical in the body.
“Vitamin E complex is helpful for healthy immune and cardiovascular function,
as well as preventing cholesterol fractions from oxidizing into more harmful
forms,” noted Neil Levin, CCN, nutrition education manager, NOW Foods.
While vitamins C and E may be essential and well-studied, the hottest
antioxidant on the scene would probably be coenzyme Q10 (CoQ10). “This
is the spark plug that ignites the energy production within the cell, keeping it
alive and healthy,” Myers said. “CoQ10 facilitates the energy process, but
also works as an antioxidant by picking up free molecules and taking them
elsewhere during the chain reaction that creates energy. CoQ10 is so important
that the body makes the majority of what you need; however, the older you get,
the less CoQ10 the body can produce.”
Geilman also called out CoQ10 as the most important single antioxidant.
“CoQ10 is designed to be an electron sink and is necessary for the
mitochondria to produce ATP, which is the currency of energy in the cell,” he
said. “Controlled free radical production is the key to respiration, and CoQ10
is the controlling factor.”
Controlling free radical production and quenching ROS before the chain
reaction of damage can occur is particularly important, as oxidative stress has
also been associated with the pathogenesis of many human diseases. However, it
is still unknown whether the oxidative stress is the cause or a consequence of
such diseases. This hasn’t prevented great interest among scientists to
elucidate the interaction between antioxidants and disease pathogenesis. As of
mid-October 2007, for example, there were more than 280 U.S. government- funded
studies recruiting or in planning stages examining different antioxidants and
disease conditions.
What does this mean for supplementation? Most marketers encourage consumers
to take a comprehensive multivitamin/mineral product as a foundation, and then
look at the science to see whether other compounds might provide extra support.
“People should consider using a multivitamin as a nutritional base, and taking
additional antioxidants to meet their individual needs,” Levin said. “Family
history and other risk factors will frequently identify areas where specific
nutrients can be helpful in maintaining optimal health against known challenges.
This provides both a framework and motivation to optimize protective
nutrition.”
Herman added: “Specialized antioxidant formulations are an important
addition to the supplement landscape, as important research has found a link
between the benefits of fruit-based antioxidants and specific health issues,
such as joint support, menopause, cardiovascular support and many other
conditions.”
While free radicals and antioxidants play a role in every cell in the body,
there are a few areas that are generating more investigation than others.
Protecting the Brain
The brain’s high levels of lipids make it especially susceptible to
oxidation. As is the case in the rest of the body, oxidation can damage cells,
tissues and genetic material in the brain. Cellular generation of ROS causes
oxidative damage to nucleic acid, carbohydrate, protein and lipid components of
the brain, where damaged neuronal cells cannot be readily regenerated.8
Unchecked oxidation can contribute to degenerative illnesses such as
Alzheimer’s disease (AD), Parkinson’s disease (PD) and dementia.
Studies have found positive results from interventions with antioxidant
compounds. Italian researchers drew a connection between AD and mild cognitive
impairment, and depressed peripheral levels of antioxidants, including vitamins
A, C and E, carotenoids (lutein, zeaxanthin, beta-cryptoxanthin,
lycopene, alpha-carotene and beta-carotene) and SOD.9 French
scientists reported older adults with low cognitive function appear to have
lower levels of lycopene and zeaxanthin.10
Tocotrienol, a specific form of vitamin E, may be able to protect against
neurological maladies marked by oxidative stress.11 Researchers have
linked higher intake of vitamin E, from both food and supplements, to a
reduction in cognitive decline seen in aging.12
CoQ10 plays a particularly critical role in the brain. Scientists have found
CoQ10 supplementation may help stave off AD, PD and other neurodegenerative
disorders.13 CoQ10 supplementation appears to protect neuronal cells
from amyloid peptide toxicity by reducing the concentration of superoxide anion.14
Combined supplementation with CoQ10 and alpha-tocopherol in aged mice improved
brain function, as measured by cognitive tests, according to research from the
University of North Texas, Fort Worth.15
Another powerful antioxidant for brain function, alpha lipoic acid (ALA),
is water- and fat-soluble and is capable of crossing the blood-brain barrier.
Clinical studies have shown ALA may help maintain healthy memory and mental
focus,16 and improve memory, especially in older adults.17
The endogenous antioxidant hormone melatonin scavenges free radicals
quite well, especially in brain tissue. Not only does it combat oxidative stress
in the hippocampus by increasing tissue levels of GPx, SOD and other antioxidant
enzymes,18 it also protects the brain from oxidative stress common in
PD by scavenging hydroxyl radicals in the mitochondria.19
From the botanical realm, grape seed extract may protect the nervous
system from ROS,20 and shield the brain from oxidative damage by
inhibiting free radical-induced lipid peroxidation.21 Pomegranate antioxidant
phenols are also neuroprotective, although the exact mechanism behind its
ability to reduce the amyloid load in AD has not been determined.22
Visualizing the Benefit
While the eyes serve as windows to the soul, they’re also windows that let
in UV light, a key contributor to oxidation. The retina is an ideal environment
for the generation of free radicals since it has both high levels of blood (and
thus oxygen) supply and high light exposure. Further, the eye’s photoreceptor
membranes are rich in polyunsaturated fatty acids, making them particularly
susceptible to oxidative damage.
Antioxidants, therefore, serve a vital role. In fact, the research is strong
enough that the U.S. National Eye Institute (NEI) has urged adults who have or
are at risk of age-related macular degeneration (AMD)—a leading cause of
blindness—to consider taking supplements based off the formulation used in the
long-term Age- Related Eye Disease Study (AREDS)—vitamins C, E, beta-carotene
and zinc.23 The AREDS study found high-dose antioxidant
supplementation reduced the risk of progression to advanced AMD by 25 percent,
and the risk of moderate vision loss by 19 percent.24
Carotenoids are particularly important antioxidants in the eyes. The
connection between retinal protection and lutein and zeaxanthin is
based in the macular pigment, which contains healthy amounts of each carotenoid.
Supplementation with lutein and zeaxanthin may prevent retinal degeneration via
protection from damaging sunlight.25 In one trial, 90 AMD patients
who supplemented for 12 months with 10 mg/d lutein (as FloraGLO® Lutein, from
Kemin Health) alone, or in conjunction with a broad spectrum antioxidant formula
including vitamins and minerals, showed improved visual function.26
Additional research out of England found administration of 20 mg/d lutein ester
(as Xangold®, from Cognis), equivalent to 10 mg/d free lutein, benefited
patients with early AMD by increasing macular pigment optical density (MPOD) and
plasma lutein concentrations.27
The carotenoid astaxanthin may also protect the eyes from lipid
peroxidation, as studies have shown combining astaxanthin with lutein and
zeaxanthin can decrease lipid peroxidation and oxidative stress markers in human
lens epithelial cells exposed to UV radiation.28
Fat-soluble carotenoids are joined in their quest to protect the eyes from
oxidative stress by a host of water-soluble flavonoid compounds. Specific
flavonoids that may protect the eyes against antioxidant damage include quercetin
and the green tea polyphenol epigallocatechin gallate (EGCG).29
Anthocyanins, another class of flavonoids, are found in a wide range of fruits,
particularly berries, and may help improve vision and preserve capillary
integrity.30 In particular, anthocyanins from bilberry,
lignonberry (Vaccinium vitis-ideae) and black currant (Ribes nigrum)
may protect against lipid and protein oxidation in the eye.31
Flavonoids from French maritime pine bark extract (as Pycnogenol®, from Natural
Health Science) may also inhibit oxidative damage and increase activity of GPx
and glutathione reductase in the retina, inhibiting diabetic retinopathy and
cataract formation.32
The Heart of the Matter
The role of oxidation in disease pathology has been most elucidated in
cardiovascular disease (CVD). Specifically, oxidation of low-density lipoprotein
(LDL), the “bad” cholesterol, appears to trigger the process of
atherogenesis, the development of fatty buildups in the arteries. This can
progress into atherosclerosis and CVD.
The American Heart Association (AHA) recommends people consume a diet high in
food sources of antioxidants and other heart-protecting nutrients, such as
fruits, vegetables, whole grains and nuts; it doesn’t recommend the use of
antioxidant supplements to prevent CVD “until more complete data are
available.”
However, there has been a good deal of research into the use of specific
antioxidants to promote heart health. Vitamin E is possibly best known for its
activity in this area. Vitamin E has been shown to inhibit lipid peroxidation of
low-density lipoprotein (LDL) cholesterol and/or atherosclerosis.33,34,35
It also has limited oxidative stress in hypertensive animals.36
CoQ10 also plays a key role in heart health, as it can protect heart cell
mitochondria from oxidative stress and damage.37,38 “The heart is
so dependent on a constant, uninterrupted stream of energy, that each cell in
the heart could have up to 4,000 mitochondria, compared to just a few in most
cells” Myers noted. “In conditions that affect the heart muscle, like heart
attack or cardiomyopathy, adding CoQ10 helps improve the muscular function of
the heart.”
In animal research, CoQ10 supplementation (as Q-Gel®, from Tishcon) has
reduced markers of oxidative damage and inhibited development of
atherosclerosis.39 Similar findings have been reported in human
trials, in which CoQ10 supplementation can modify oxidative stress and the
atherogenic ratio, while increasing the activity of endogenous antioxidant
enzymes.40,41
Researchers have also turned to carotenoids and flavonoids to help the heart.
In a study in hypertensive patients, 250 mg/d of lycopene-rich tomato
extract (as Lyc-O-Mato, from LycoRed) reduced lipid peroxidation markers, and
both systolic and diastolic blood pressure readings.42 Similarly, a
study out of California showed one month of supplementation with grape seed
extract (as MegaNatural® BP, from Polyphenolics) could significantly reduce
blood pressure and the concentration of oxidized LDL in plasma.43
Green tea’s EGCG may also prevent oxidative modifications of LDL,44
reduce surrogate markers of atherosclerosis and lipid peroxidation, and reduce
postprandial lipidemia in hypercholesterolemic subjects.45
Berries are also rich in antioxidant polyphenols. Cranberry flavonoids
have been shown to reduce lipid peroxidation in atherosclerosis and CVD,46
while blueberry’s polyphenols may inhibit ROS formation in red blood
cells. Pomegranate, meanwhile, can reduce oxidative stress in macrophage47
and endothelial cells.48
One specialty product—Radical Fruits™, from Garden of Life— combines
raspberry, prune, pomegranate, blueberry, grape and strawberry extracts, and was
the subject of a randomized, double blind, placebo-controlled trial.49
Hypercholesterolemic subjects taking 900mg Radical Fruits three times daily for
four weeks had reduced plasma total cholesterol, increased high-density
lipoprotein (HDL) cholesterol and decreased urinary oxidative markers.
“Conducting primary research on our Radical Fruits formula was important,”
said Garden of Life’s Leonid Ber, M.D. “Rather than just a combination of
other research studies, we really showed that this specific formula has
biological activity in the body.”
They’ve Got Muscles
It’s not just the organs looking for support from antioxidants; muscles are
also subjected to free radical damage. During exercise, oxygen consumption
increases significantly, which leads to a large increase in production of
oxidants, resulting in damage that contributes to muscle fatigue during and
after exercise. The inflammatory response that occurs after exercise is also
associated with oxidative stress, as free radicals are produced by neutrophils
to remove tissue damaged by exercise; therefore, antioxidants can promote
recovery and muscle adaptation.
Vitamin C has been extensively studied in cases of exercise-induced oxidative
stress.50 In one study, insufficient vitamin C status correlated to
low serum concentrations of lipid peroxides and increased muscle damage in
female weightlifters.51 A Spanish study found vitamin C
supplementation in volunteer endurance athletes increased antioxidant enzymes
and plasma antioxidant levels during athletic competition and short-term
recovery.52 Vitamin C taken on a regular basis before rigorous
exercise may even reduce muscle soreness, delay creatine kinase increases and
prevent blood glutathione oxidation.53
Combining vitamin C with vitamin E and beta-carotene may have further
benefits, according to a stuffy from Universitat de les Illes Balears, Spain.54
Male athletes who received 500 mg/d vitamin E, 30 mg/d beta-carotene and 1 g/d
vitamin C for three months during training had a higher maximal oxygen uptake
and lower increases in blood lactate concentration, improving the efficiency of
obtaining aerobic energy.
Antioxidant Synergy
While antioxidants have been studied for their specific attributes and
activities, it is the greater synergy that benefits the body. In addition, the
action of one antioxidant of ten is dependent on the actions of others
throughout the system. “Supplementing with a variety of antioxidants is
important for maximizing their individual effects, since research has shown
certain antioxidants act synergistically with one another, and because different
types of antioxidants act in different parts of the cellular milieu,” said Bob
Terry, Ph.D., technical services director, Green Foods Corp.
Myers agreed with the assessment. “We pay lip service to how important
diversity is in many parts of society, but this is an area where it’s
critical,” she said. “We want to take in thousands of phytonutrients through
our diet by consuming the broadest range of locally grown, fresh fruits and
vegetables. The wider variety of antioxidants you get, the more likely you’ll
have improved health. There is no one size fits all.”
Lizanne Falsetto, CEO, thinkproducts, affirmed the importance of a diet rich
in fruits and vegetables, which are themselves loaded with interconnected
antioxidant compounds. “A recent study stated fruits and vegetables in
combination have synergistic effects on antioxidant activities, leading to
greater reduction in risk of heart disease and cancers,” she said.
“Consumers are best off taking a synergistic complex of naturally occurring
antioxidants.”
Part of this search for synergy is driving interest in whole foods and
superfoods. “There is ample nutrition available in real, whole, organic
foods,” said Mic LeBel, a public relations professional who works with
companies including Guayaki Yerba Mate and Amazing Grass. “Many companies are
offering functional foods and beverages that offer antioxidants and a wealth of
other key nutrients via whole foods as opposed to supplements or nutrient
fortification.”
Jeremy Black, vice president of marketing, Sambazon, added: “Whole food
nutrition is a concept that seems to be resonating with more people and is
something we’ve always based our products on.” His assessment was shared by
Zach Adelman, president and founder of Navitas Naturals, which supplies
functional foods and supplements. “There are these nutritious foods that are
being discovered and brought to America from around the world,” he said,
specifically mentioning goji berries, cacao seeds, camu camu, pomegranate, açaí
and maca root. “These foods are different and unusual for consumers, so
retailers can demo them and help shoppers taste the foods and learn how to
integrate them into their daily diet.”
Terry said the launch of more exotic offerings is complemented by
long-standing product SKUs like green foods. “Whole food sources of
antioxidants may be obtained from whole food supplements processed in a manner
that protects and stabilizes their constituent antioxidants,” he said.
“Fortunately, fruit, vegetable and green cereal grass and whole food powders
are made specifically to provide an excellent array of antioxidants and other
supportive nutrients that can help us obtain the full spectrum ‘rainbow
diet’ every day.”
Mike Pugh, senior manager of research and development, XanGo, also advocated
consumers seek whole food nutrition. “Historically, whole foods have been
consumed by people for hundreds of years as part of a regular diet, and science
is now identifying specific properties within these foods that benefit human
health and wellness,” he said. “We believe whole foods are the best option
for obtaining those nutrients, and that is why we use a whole fruit puree of the
mangosteen fruit in our product.”
While the functional foods and beverage space is seeing a number of product
launches to maximize on this interest, retailers need to ensure the products are
delivering quality nutrition. “Just adding an active substance to a food or
liquid without extensive testing may create a marketable product, but one that
risks being spoiled or poorly utilized by the body,” Levin said.
“Interactions that lead to degradation of potency or proliferation of
undesirable microbes are some potential problems affecting the stability and
potency of functional food ingredients, because long-term stability of
ingredients added to foods is still largely unknown. Proper testing of products
and packaging is a must.”
The quest for quality also means staying up to date with current research and
asking for product substantiation, Clow said. “To make intelligent
recommendations to consumers, it’s important to understand the features and
benefits of the products you’re offering,” she said. In addition, she
suggested asking questions of consumers to establish the best product to suit
their needs: What kind of support are they looking for? Do they have any special
dietary restrictions, nutritional needs or health concerns? Are they willing to
take three to six multivitamin tablets a day, or would they prefer a one-a-day?
This can also help broach the topic of specific health concerns, which make the
goal of supplementation more tangible.
Ultimately, Vrablic said, “antioxidant protection is hard to ‘see’.
Retailers need to address consumer concerns such as anti-aging, skin health, eye
health and immune health, which are all a function of overall antioxidant
health. Education plays a key role in understanding antioxidants and the role
they play in everyday wellness, and retailers should partner with manufacturers
to help customers make wise and confident supplement choices.”
And while the science continues to evolve, retailers are on the front lines
helping consumers fight the degeneration induced by free radical damage.
“Follow the clinical science to guide you to antioxidant substances that are
best supported for the customer’s needs, [but] don’t worry if the science is
preliminary or not yet definitive, as long as it is promising,” Levin said.
“By the time it is officially accepted, it will probably be 20 or 30 years
from now. We simply can’t wait that long to stave off the ravages of aging by
using safe, natural antioxidants.”
1. Dragsted LO et al. "The 6-a-day study: effects of fruit and
vegetables on markers of oxidative stress and antioxidative defense in healthy
nonsmokers. Am J Clin Nutr. 79, 6:1060-72, 2004. www.ajcn.org
2. Taylor EW et al. “Nutrition, HIV, and drug abuse: the molecular basis of
a unique role for selenium.” J Acquir Immune Defic Syndr. 25 Suppl
1:S53-61, 2000.
3. Muth CM et al. “Influence of an orally effective SOD on hyperbaric
oxygen-related cell damage.” Free Radic Res. 38(9):927-32, 2004.
4. Vouldoukis I et al. Phytother Res. 18, 12:957-62, 2004.6:411-22,
1989.
5. Laurin D et al. "Midlife dietary intake of antioxidants and risk of
late-life incident dementia: the Honolulu-Asia Aging Study." Am J
Epidemiol. 159, 10:959-67, 2004.www.aje.oupjournals.org
6. Age-Related Eye Disease Study Research Group. “A randomized,
placebo-controlled, clinical trial of high-dose supplementation with vitamins C
and E, beta carotene, and zinc for age-related macular degeneration and vision
loss: AREDS report no. 8.” Arch Ophthalmol. 119, 10:1417-36, 2001. http://archopht.ama-assn.org
7. Erbs S et al. "Improvement of peripheral endothelial dysfunction by
acute vitamin C application: different effects in patients with coronary artery
disease, ischemic and dilated cardiomyopathy." Am Heart J. 146,
2:280-5, 2003. www2.us.elsevierhealth.com
8. Lau FC et al. "The beneficial effects of fruit polyphenols on brain
aging." Neurobiol Aging. 26, Suppl 1:128-32, 2005. www.elsevier.com
9. Rinaldi P et al. "Plasma antioxidants are similarly depleted in mild
cognitive impairment and in Alzheimer's disease." Neurobiol Aging 24,
7:915-9, 2003. www.elsevier.com
10. Akbaraly NT et al. “Plasma carotenoid levels and cognitive performance
in an elderly population: results of the EVA Study.” J Gerentol Med Sci.
2007; 62A(3)308-16. http://biomed.gerontologyjournals.org
12. Morris MC et al. “Vitamin E and cognitive decline in older persons.” Archives
of Neurology. 59:1125-32, 2002. http://archneur.ama-assn.org
13. Joseph JA, et al “Reversals of Age-Related Declines in Neuronal Signal
Transduction, Cognitive, and Motor Behavioral Deficits with Blueberry, Spinach,
or Strawberry Dietary Supplementation”, J Neurosci. 1999;19:8114-8121. http://www.jneurosci.org/cgi/reprint/19/18/8114.pdf
14. Li G. et al. “Coenzyme Q10 protects SHSY5Y neuronal cells from beta
amyloid toxicity and oxygen-glucose deprivation by inhibiting the opening of the
mitochondrial permeability transition pore.” Biofactors.
2005;25(1-4):97-107. http://iospress.metapress.com/link.asp?id=83968yv8l68253y0
15. McDonald SR et al. "Concurrent administration of coenzyme Q10 and
alpha-tocopherol improves learning in aged mice." Free Radic Biol Med.
38, 6:729-36, 2005.www.elsevier.com
16. Hager K et al. "Alpha-lipoic acid as a new treatment option for
Alzheimer type dementia." Arch Gerontol Geriatr, 32, 3:275-82, 2001.
17. Liu J. “The Effects and Mechanisms of Mitochondrial Nutrient
alpha-Lipoic Acid on Improving Age-Associated Mitochondrial and Cognitive
Dysfunction: An Overview.” Neurochem Res. 2007 Jun 29; Epub ahead of print. http://www.springerlink.com/content/9610161628604736/
18. Gomez M et al. "Pro-oxidant activity of aluminum in the rat
hippocampus: gene expression of antioxidant enzymes after melatonin
administration. Free Radic Biol Med. 38, 1:104-11, 2005.www.sciencedirect.com
20. Balu M et al. “Age-related oxidative protein damages in central nervous
system of rats: modulatory role of grape seed extract.” Int J Dev Neurosci.
23(6):501-7, 2005. http://dx.doi.org/10.1016/j.ijdevneu.2005.06.001
21. Balu M et al. “Modulatory role of grape seed extract on age-related
oxidative DNA damage in central nervous system of rats.” Brain Res Bull.
68(6):469-73, 2006.
22. Hartman RE et al. “Pomegranate juice decreases amyloid load and
improves behavior in a mouse model of Alzheimer's disease.” Neurobiol Dis.
24(3):506-15, 2006. http://dx.doi.org/10.1016/j.nbd.2006.08.006
23. Coleman H, Chew E. “Nutritional supplementation in age-related macular
degeneration.” Curr Opin Ophthalmol. 2007 May;18(3):220-3.
24. Sackett CS, Schenning S. “The age-related eye disease study: the
results of the clinical trial.” Insight. 2002 Jan-Mar;27(1):5-7.
25. Krinsky NI et al. "Carotenoid actions and their relation to health
and disease. Mol Aspects Med. 26, 6:459-516, 2005.www.sciencedirect.com
26. Richer S et al. “Double-masked, placebo-controlled, randomized trial of
lutein and antioxidant supplementation in the intervention of atrophic
age-related macular degeneration: the Veterans LAST study (Lutein Antioxidant
Supplementation Trial).” Optometry. 75, 4:216-30, 2004.
27. Koh HH. "Plasma and macular responses to lutein supplement in
subjects with and without age-related maculopathy: a pilot study. Exp Eye
Res. 79, 1:21-7, 2004. www.sciencedirect.com
28. Chitchumroonchokchai C et al. “Xanthophylls and alpha-tocopherol
decrease UVB-induced lipid peroxidation and stress signaling in human lens
epithelial cells.” J Nutr. 134, 12:3225-32, 2004. http://jn.nutrition.org/cgi/content/full/134/12/3225
29. Hanneken A et al. “Flavonoids protect human retinal pigment epithelial
cells from oxidative-stress-induced death.” Invest Ophthalmol Vis Sci.
2006 Jul;47(7):3164-77.
30. Ghosh D, Konishi T. “Anthocyanins and anthocyanin-rich extracts: role
in diabetes and eye function.” Asia Pac J Clin Nutr. 2007;16(2):200-8.
31. Viljanen K et al. “Inhibition of protein and lipid oxidation in
liposomes by berry phenolics.” J Agric Food Chem. 2004 Dec
1;52(24):7419-24.
32. Kamuren ZT et al. “Effects of low-carbohydrate diet and Pycnogenol
treatment on retinal antioxidant enzymes in normal and diabetic rats.” J
Ocul Pharmacol Ther. 22, 1:10-8, 2006.
33. Ismail NM et al. "Vitamin E and factors affecting atherosclerosis in
rabbits fed a cholesterol-rich diet." Int J Food Sci Nutr. 51
Suppl:S79-94, 2000.
34. Kaikkonen J et al. "Supplementation with vitamin E but not with
vitamin C lowers lipid peroxidation in vivo in mildly hypercholesterolemic
men." Free Radic Res. 35, 6:967-78,
2001.http://www.tandf.co.uk/journals/titles/10715762.asp
35. Cherubini A et al. "High vitamin E plasma levels and low low-density
lipoprotein oxidation are associated with the absence of atherosclerosis in
octogenarians." J Am Geriatr Soc. 49, 5:651-4, 2001.www.blackwell-synergy.com
36. Frenoux JM et al. "Very high alpha-tocopherol diet diminishes
oxidative stress and hypercoagulation in hypertensive rats but not in
normotensive rats. Med Sci Monit. 8, 10:BR401-7, 2002.www.medscimonit.com
37. Conklin KA et al. Coenzyme q10 for prevention of anthracycline-induced
cardiotoxicity. Integr Cancer Ther. 4, 2:110-30, 2005. http://www.sagepub.com/journal.aspx?pid=286
38. Lakomkin VL et al. "Changes in antioxidant status of myocardium
during oxidative stress under the influence of coenzyme Q10. Biochemistry
(Mosc). 70, 1:79-84, 2005.
39. Singh RB et al. "Effect of coenzyme Q10 on experimental
atherosclerosis and chemical composition and quality of atheroma in
rabbits." Atherosclerosis. 148, 2:275-82, 2000.www.elsevier.com
40. Chapidze G et al. "Prevention of coronary atherosclerosis by the use
of combination therapy with antioxidant coenzyme Q10 and statins. Georgian
Med News. 118:20-5, 2005.
41. Lakomkin VL et al. "Changes in antioxidant status of myocardium
during oxidative stress under the influence of coenzyme Q10. Biochemistry
(Mosc). 70, 1:79-84, 2005.
42. Engelhard YN et al. "Natural antioxidants from tomato extract reduce
blood pressure in patients with grade-1 hypertension: a double-blind,
placebo-controlled pilot study. Am Heart J. 151, 1:100, 2006.www.elsevier.com
44. Ostrowska J and Skrzydlewska E. “The comparison of effect of catechins
and green tea extract on oxidative modification of LDL in vitro.” Adv Med
Sci. 51:298-303, 2006.
45. Basu A, Lucas EA. “Mechanisms and effects of green tea on
cardiovascular health.” Nutr Rev. 2007 Aug;65(8 Pt 1):361-75.
47. Rosenblat M et al. "Pomegranate byproduct administration to
apolipoprotein e-deficient mice attenuates atherosclerosis development as a
result of decreased macrophage oxidative stress and reduced cellular uptake of
oxidized low-density lipoprotein." J Agric Food Chem. 54, 5:1928-35,
2006. http://pubs.acs.org/journals/jafcau/index.html
48. de Nigris F et al. “Effects of a pomegranate fruit extract rich in
punicalagin on oxidation-sensitive genes and eNOS activity at sites of perturbed
shear stress and atherogenesis.” Cardiovasc Res. 73(2):414-23, 2007. http://dx.doi.org/10.1016/j.cardiores.2006.08.021
49. Abidov M et al. “Efficiency of pharmacologically-active antioxidant
phytomedicine Radical Fruits in treatment hypercholesteremia at men.” Georgian
Med News. 140:78-83, 2006.
51. Liu JF et al. "Blood Lipid Peroxides and Muscle Damage Increased
following Intensive Resistance Training of Female Weightlifters." Ann N
Y Acad Sci. 1042:255-61, 2005. www.annalsnyas.org
52. Tauler P et al. "Influence of vitamin C diet supplementation on
endogenous antioxidant defences during exhaustive exercise." Pflugers
Arch. 446, 6:658-64, 2003.
53. Bryer SC and Goldfarb AH. “Effect of high dose vitamin C
supplementation on muscle soreness, damage, function, and oxidative stress to
eccentric exercise.” Int J Sport Nutr Exerc Metab. 16(3):270-80, 2006.
54. Aguila A et al. “Antioxidant diet supplementation enhances aerobic
performance in amateur sportsmen.” J Sports Sci. 2007
Sep;25(11)1203-10.
To take the exam for this course, please make sure you have the course in your
nutrilearn.com profile. If you need to add the course to your profile
click here
and complete the checkout process.
If you already have the course in your profile and are ready to take the test,
click here
or visit your profile once you are logged in to the nutrilearn system. Note: To access the
available courses in your profile, click on the "courses" link at
the top of the page once you are logged in.
Oxidants
can damage cells by starting chemical chain reactions, or by damaging DNA at the
cellular level. “Our DNA is the blueprint for life,” said Cheryl Myers,
director of product development, Enzymatic Therapy. “If the blueprint is
damaged, you have problems when the cell goes to recreate itself. Either it ’s
not as efficient or you have mutations in the cell. So preventing that DNA
damage is critical to managing all aspects of the degeneration process in our
bodies.”