UF news release on supplements

[Guest guest]

Since so many of us supplement, I thought this article might be of

interest.

in fl

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UF expert: Don't go overboard with dietary supplements

FOR IMMEDIATE RELEASE / Photo Available

By Tom Nordlie

GAINESVILLE, Fla.---Health conscious? Don't overdo the

nutritional supplements, advises a University of Florida nutritional

biochemist.

" Some people may use excessive amounts of nutrients for

weight loss, athletic performance or health maintenance, without

considering possible adverse effects, " said Bob Cousins, who

helped formulate new recommendations on nutrients for the

National Academies' Institute of Medicine in Washington, D.C.

The recommendations are part of a report on Dietary

Reference Intakes released by the academies earlier this month.

Cousins served on a panel of experts that examined the

nutritional value of vitamins A and K, arsenic, boron, chromium,

copper, iodine, iron, manganese, molybdenum, nickel, silicon,

vanadium and zinc.

Besides updating the well-known Recommended Dietary

Allowances, or RDAs, the panel estimated -- for the first time --

nutrient intake levels " that are likely to pose no risk of adverse

health effects. " These levels serve as recommended maximums for

daily intake and are called " tolerable upper intake levels. " The

report says these levels are not likely to be obtained from ordinary

foods, Cousins said.

" These new recommended maximums are a sign of the

times, " said Cousins, professor and eminent scholar with UF's

Institute of Food and Agricultural Sciences. " Many of the nutrients

reviewed in our study are being consumed in amounts that would

be impossible to achieve through diet alone. "

Iron supplements have long been used to prevent anemia,

particularly among pregnant women, he said. The panel's new

recommended intake for pregnant women -- 27 milligrams per day -

- is about half the tolerable upper intake level recommended for

healthy adults -- 45 milligrams per day.

" Excessive iron intake can cause gastrointestinal distress, "

Cousins said. " It may also be linked to heart disease and cancer in

people genetically predisposed to accumulate high levels of iron. "

Zinc, popular in cold remedies, has a new recommended

maximum intake of 40 milligrams per day. But the average zinc

cold lozenge contains more than 20 milligrams of the mineral,

Cousins said. Excessive zinc intake can lead to copper deficiency

and cause anemia, and may cause immune system disfunction.

" A few zinc lozenges combined with zinc intake from foods

like red meat can put your daily intake way over the tolerable upper

intake level, " said Cousins, an international expert on zinc. " In the

short term, our bodies can cope with high levels of many nutrients,

but the long-term effects are unknown. " Cousins, who directs UF's

Center for Nutritional Sciences, said nutrient toxicity has not been

closely studied, and ethical considerations limit research on human

subjects.

" As a result, many nutritional supplements have never been

tested in well-controlled trials, " he said.

One example is chromium, used in diet aids such as

chromium picolinate. Chromium's role in human nutrition is unclear,

so the panel did not establish a recommended intake for the metal,

he said.

" Chromium is believed to play some role in glucose

regulation, " Cousins said. " But long-term effects of chromium

supplementation have not been widely studied. "

Substantial amounts of chromium and other nutrients are

routinely added to " meal replacement " drinks and candy bars

marketed to dieters and athletes, he said.

" More and more products are fortified with nutrients today,

and you probably don't want to carry a pocket calculator to the

dinner table to keep track, " Cousins said. " But if you eat a

balanced diet of foods from each of the food groups and watch

your supplement use, you should be fine. "

Cousins, elected as a member of the National Academy of

Sciences in May, said the public is becoming more aware of

nutrition-related issues. He believes the report will influence

advertising, food labeling and government policy decisions. The

report is the fourth in a series of seven, developed by the United

States and Canada to review nutritional data.

Other recommendations in the report include:

* Vitamin A -- Essential to vision and reproduction, vitamin A is

produced from carotenes found in carrots, sweet potatoes,

broccoli, meat and eggs. Recommended daily intake is 900

micrograms for men, 700 for women. The report says that to

achieve these intakes, more vegetables and fruits must be

consumed than was previously believed. Tolerable upper intake

level is 3 milligrams per day; excessive intake may increase the

risk of birth defects, skull malformations in children and liver

abnormalities in adults.

* Vitamin K --Necessary for blood clotting, vitamin K is found in

leafy green vegetables. Adequate daily intake is 120 micrograms

for men, 90 for women. No tolerable upper intake level was

established.

* Copper -- Used for development of connective tissue, nerve

coverings and skin pigment, copper is found in organ meats,

seafood, nuts and seeds. Recommended daily intake is 900

micrograms for both men and women. This is the first time a

recommended intake for copper was established. Tolerable upper

intake level is 10 milligrams per day; excessive intake may cause

liver damage.

* Iodine -- An important component of thyroid hormones, iodine

occurs in small amounts in seafood and is often added to table

salt. Recommended daily intake is 150 micrograms for men and

women. Tolerable upper intake level is 1.1 milligrams per day;

excessive intake can cause abnormal functioning of the thyroid

gland in some individuals.

* Manganese -- Involved in metabolism and bone formation,

manganese is found in nuts, legumes, whole grains and tea.

Adequate daily intake is 2.3 milligrams for men, 1.8 for women.

Tolerable upper intake level is 11 milligrams per day for adults;

excessive intake may cause neurological side effects.

* Molybdenum -- Used for enzyme enhancement, molybdenum is

found in nuts, legumes and grain products. Recommended daily

intake is 45 micrograms for men and women. Tolerable upper

intake level is 2 milligrams per day; excessive intake may cause

impaired reproduction and growth.

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Recent UF Health Science Center news releases are

available at www.health.ufl.edu/hscc/index.html

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Academic components of the UF Health Science Center

include the colleges of Dentistry, Health Professions, Medicine,

Nursing, Pharmacy and Veterinary Medicine. Clinical enterprises

of the UF Health Science Center include Shands Hospital at UF,

the UF Faculty Group Practice and a statewide network of UF-

affiliated hospitals and clinics. Their web sites can be accessed

through www.health.ufl.edu

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