placed on phytonutrient supplements containing any
isolated form ofvitamin Aor beta-carotene.Interactions
Though beneficial for certain conditions, phytonu-
trient supplements can not always capture the many
different interactions of the phytonutrients found in
food. For example, flavonoids and carotenoids are
believed to have more health-promoting properties
when they are taken together rather than separately in
a supplement. The hundreds of phytonutrients present
in plant foods help each other biochemically—and pre-
sumably also in the body. The food science and phar-
maceutical developments of the past decades have
consistently demonstrated the need to consume a
broad range of whole foods on a regular basis. Eating
a whole tomato is better than taking a supplement that
contains a phytochemical isolated from a tomato. Eat-
ing a carrot does not only provide the beta carotene that
could be obtained in a pill, but also the health benefits
of hundreds or thousands of other phytonutrients that
have not yet been identified or characterized. Some
interactions are possible between phytonutrients. Citrus
bioflavonoid preparations, such as grapefruit juice,
may interact with drugs containing naringin. Naringin
increases the oral bioavailability ofcalciumchannel
blocker medications such as: nifedipine, verapramil
and felodipine. Naringin may enhance the effect of
these drugs and result in a serious drop in blood pres-
sure. Naringin also inhibits the breakdown of various
drugs such ascaffeine, coumarin, and estrogens. It is
recommended to avoid flavonoid preparations con-
taining naringin when taking any of these drugs.
Studying the health benefits of individual phytonu-
trients is just one aspect of understanding how fruits
and vegetables contribute to health, buy much
research remains to be done on how the phytonu-
trients interact with each other and how they may
protect against disease.Aftercare
In case of adverse or allergic reaction, the use of
phytonutrient supplements should be discontinued.Complications
One risk associated with phytonutrients is if they
are taken as supplements because they are then in a
concentrated and more potent form. Hence, some may
cause allergic reactions in hypersensitive people. They
should also be kept out of reach of children. As with
any nutritional supplement, a healthcare professional
should be consulted if taken by pregnant or lactatingwomen or by people with health conditions. For
example, cauliflower contains goitrogens that can
interfere with the functioning of the thyroid gland.
Individuals with already existing medical problems
may have to avoid specific phytonutrients.Parental concerns
There is a danger that phytonutrient classifica-
tions over-simplify the process of building a healthy
diet. Most foods are packed with protective phytonu-
trients. They are present in all plant foods, and eating a
wide variety of fruits and vegetables should be pre-
ferred to taking specific supplements, unless recom-
mended by a health practitioner. Information on the
disease-fighting functions of phytonutrients is becom-
ing widely available and should be used to understand-
ing their many properties. It is not possible to cover all
of the cautions for people considering the purchase of
phytonutrient supplements. However, one simple sen-
tence covers whole foods and whole food supplements:
they can be a safe and important method by which
people improve their health and well-being because
they are made from the whole fruit or vegetable and
do not just contain isolated components.Resources
BOOKS
Artschwager-Kay, M., Weil, A.Healing With Plants in the
American and Mexican West.Tucson, AZ: University
of Arizona Press, 1996.
Balch, P. A.Prescription for Herbal Healing: An Easy-to-Use
A-Z Reference to Hundreds of Common Disorders and
Their Herbal Remedies.Torquay, UK: Avery, 2002.
Balch, P. A.Prescription for Nutritional Healing, 4th Edition:
A Practical A to Z Reference to Drug–Free Remedies
Using Vitamins, Minerals, Herbs & Food Supplements.
Torquay, UK: Avery, 2006.
Bratman, S., Kroll, D.The Natural Pharmacist: Natural
Health Bible from the Most Trusted Alternative Health
Site in the World: You’re A-Z Guide to Over 300 Con-
ditions, Herbs, Vitamins, and Supplements.New York,
NY: Three Rivers Press, 2000.
Deutsch-Mozian, L.Foods That Fight Disease: A Simple
Guide to Using and Understanding Phytonutrients to
Protect and Enhance Your Health.London, UK: Avery
(Penguin Group), 2003.
Grieve, M.A Modern Herbal. The Medical, Culinary, Cos-
metic and Economic Properties, Cultivation, and Folk-
lore of Herbs, Grasses, Fungi, Shrubs and Trees with
All Their Modern Scientific Uses.New York, NY:
Dorset, 1992.
Larson Duyff, R.ADA Complete Food and Nutrition Guide,
3rd ed.Chicago, IL: American Dietetic Association,
2006.
Tucker, G., Salter, A.Phytonutrients.London, UK: Black-
well Publishing, 2008.Phytonutrients