Definition: Phytochemicals are naturally
occurring chemicals produced by plants. They are biologically active and
may affect your health, however, unlike vitamins and minerals, they're
not considered to be essential nutrients.
Dietary sources of
phytochemicals include fruits, vegetables, nuts, seeds, and legumes.
While there is a fair amount of evidence that eating a diet rich in
plant-based foods is beneficial for your health, research hasn't
explained how much of that benefit is due to the phytochemicals.
The benefit may be due to the nutrients, fiber,
or because people who eat more plant-based foods may also be more
likely to maintain their weight better and be more active.
Despite
a lack of evidence, some phytochemicals are available in supplemental
form. These supplements are generally considered to be safe, but it's
important to speak with your healthcare provider before taking
phytochemical supplements for specific health purposes.
Some of the best-known phytochemicals include carotenoids, which includes alpha-carotene, beta-carotene, lutein, lycopene, and zeaxanthin.
All of these phytochemicals can be converted to vitamin A in your body,
but for the most part, plant-based vitamin A comes from the
beta-carotene.
Another class of phytochemicals is the flavonoids, family. Flavonoids include anthocyanidins, which come from red, blue, and purple berries and grapes; flavanols, which come from tea, chocolate, berries, grapes and apples; flavanones, which are found in citrus fruit; flavonols that come from lots of fruits and vegetables; flavones from celery and hot peppers; and isoflavones that are found in soy and legumes.
Other
phytochemicals include compounds that you might have read about such as
resveratrol that's found in grapes and peanuts; lignans found in seeds
and whole grains; phytosterols that are used to lower high cholesterol;
indole-3-carboninol that's found in cruciferous veggies; curcumin,
which is found in turmeric; and chlorophyll, which is found in anything
that's green.
Fiber can also be classified as a phytochemical because it's only
found in plants, but sometimes it's classified as a carbohydrate. There
are a number of dietary fibers including cellulose, beta-glucan,
hemicellulose, pectin, gum, inulin, oligofructose, and resistant starch.
Eating a diet high in fiber will help keep your cholesterol levels in
check, and improve digestive system function.
Eating a meal that's high in fiber can slow
down the blood sugar spikes that can occur when you eat a large amount
of sugar or starch.
Sources:
Oregon State University Linus Pauling Institute Micronutrient Information Center. "Fiber." Accessed February 22, 2016. http://lpi.oregonstate.edu/mic/other-nutrients/fiber.
Oregon State University Linus Pauling Institute Micronutrient Information Center. "Flavonoids." Accessed February 22, 2016. http://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/flavonoids.
Oregon State University Linus Pauling Institute Micronutrient Information Center. "Phytochemicals." Accessed February 22, 2016. http://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals.
By Shereen Lehman, MS
Nutrition Expert
