[PHNUTR-L] Researcher focuses on pros,
cons of antioxidants from fruits and vegetables
fivestar at nutritionucanlivewith.com
Fri Apr 20 09:16:29 PDT 2007
Colleagues, the following is FYI and does not necessarily reflect my own
opinion. I have no further knowledge of the topic. If you do not wish to
receive these posts, set your email filter to filter out any messages
coming from @nutritionucanlivewith.com and the program will remove
anything coming from me.
Public release date: 18-Apr-2007
Contact: Dr. Susanne Talcott
smtalcott at tamu.edu
Texas A&M University - Agricultural Communications
Researcher focuses on pros, cons of antioxidants from fruits and vegetables
COLLEGE STATION – Nutrition: It's not just the four basic food groups
Researcher Dr. Susanne Mertens-Talcott of Texas A&M University is
looking into how plant-based phytochemicals, including antioxidants and
herbal supplements, can be useful in the promotion of health and
prevention of chronic diseases.
This field is still growing. In the U.S. more than $20 billion was spent
on dietary supplements in 2005, said Talcott, who is in a joint research
and teaching position with the department of nutrition and food science
and the department of veterinary physiology and pharmacology.
"Over $7 billion was spent on herbal dietary supplements in 2005." These
supplements are plant-based, including grape seed extract, St. John's
wort, ginseng and biloba extract, she added.
"In addition to that there is the segment of so-called 'functional
foods,' including antioxidant foods – for example, fruit juices and
beverages and grain-based products," Talcott said.
The amount spent on these foods each year "has increased drastically;
however, we do not know yet how efficacious these different antioxidants
really are in the prevention of chronic diseases such as cardiovascular
disease and cancer," she said. "We also do not know very much about the
mechanisms, which appear to include antioxidant and anti-inflammatory
effects of these phytochemicals."
This can be important to health since these reactive oxygen species or
'free radicals' may play a role in some diseases, including Alzheimer's,
cancer and atherosclerosis, she said.
"However, other mechanisms, including the prevention of chronic
inflammation and interaction with intracellular mechanisms, may be as
important in the prevention of chronic diseases," she said. But are they
safe? Are they efficient? How much is required? And how much is too
much? Talcott is looking for the answers to these questions through her
"My overall goal is to find out more about the safety and efficacy of
phytochemical dietary supplements," she said. Because these items are
already popular with consumers, "we need to follow up with research. We
know very little about (dose) recommendations and how safe (they are)."
Phytochemicals, also called secondary plant compounds – including
antioxidants – have been defined as chemicals found in plants that have
protective or disease-fighting properties ( http://phytochemicals.info/ ).
Pomegranate juice and extract have been the focus of much of her
studies. Because these are used in different food products, they are
found as ingredients in many different items in supermarkets, Talcott said.
She has also done research on the properties of muscadine grapes and
acai, a palm fruit from Brazil, as well as isolated compounds including
quercetin and ellagic acid, which are also sold as dietary supplements.
The results of some of her studies were published in the Oct. 13, 2006,
edition of the Journal of Agricultural and Food Chemistry. The article
was titled "Absorption, Metabolism and Antioxidant Effects of
Pomegranate (Punica granatum L.) Polyphenols after Ingestion of a
Standardized Extract in Healthy Human Volunteers."
In addition to her research, Talcott teaches a class on "Special Topics
in Phytochemicals of Fruits and Vegetables" for students who are
majoring in nutrition and food science. Many of the students are
planning to enter medical or pharmacy school, she added.
"It is my goal to give students as much relevant information, which they
directly can apply in their desired profession," Talcott said.
"Consumers and patients have many questions about herbal dietary
supplements, and health care professionals and (members of the) food
industry are and will be even more confronted with these questions."
For example, Dr. Joseph M. Betz was a recent guest lecturer in Talcott's
class. Betz is the director of the Dietary Supplement Methods and
Reference Materials Program Office of Dietary Supplements at the
National Institutes of Health in Bethesda, Md. He discussed Food and
Drug Administration rules as to the differences between foods and drugs
and how each must be labeled. With regard to herbal supplements, this
can sometimes be a little tricky, he said.
During the question and answer period at the end of his talk, one of the
students asked about a recent study on antioxidants. According to news
reports, the study seemed to find that antioxidants – especially
vitamins A and E – don't have the beneficial properties they are thought
to have and may even increase mortality.
Talcott offered this clarification in regard to the study: "This study
statistically analyzed many different clinical studies with vitamins A,
E (and) C, beta-carotene and selenium. The performed statistical
analysis indicated that vitamin A and E and beta-caraotene may increase
mortality in some of the selected studies. The meaning of this study
currently is being discussed."
The study looked at synthetic antioxidants, she said, which are not the
same compounds that she is researching.
"Even though we still have a lot to learn about the efficacy, safety and
dosing recommendations for herbal supplements and antioxidant foods, we
can be confident to recommend a healthy balanced diet according to the
food-pyramid rich in fresh fruits and vegetables. I also would not see a
problem with the intake of reasonable amounts of standardized
high-quality antioxidant dietary supplements," she said
"It is my long-term goal to see science-based intake recommendations
developed for those herbal plant compounds which have a proven potential
in the promotion of health and prevention of chronic disease."
Kathrynne Holden, MS, RD < fivestar at nutritionucanlivewith.com >
"Ask the Parkinson Dietitian" http://www.parkinson.org/
"Eat well, stay well with Parkinson's disease"
"Parkinson's disease: Guidelines for Medical Nutrition Therapy"
More information about the PHNUTR-L