HOW MUCH IS TOO MUCH?Pick up any vitamin or mineral supplement. The label tells you roughly how much of each nutrient nutrient /nu·tri·ent/ (noo´tre-int) 1. nourishing; providing nutrition. 2. a food or other substance that provides energy or building material for the survival and growth of a living organism. you need. But it doesn't say how much is too much. For the first time, the National Academy of Sciences has issued Tolerable tol·er·a·ble adj. 1. Capable of being tolerated; endurable. 2. Fairly good; passable. See Synonyms at average. tol Upper Intake Levels, or ULs, to tell people how much is a safe upper limit for nearly two dozen nutrients. The Academy has also updated the Recommended Dietary Allowances Recommended Dietary Allowance (RDA) The Recommended Dietary Allowances (RDAs) are quantities of nutrients in the diet that are required to maintain good health in people. (RDAs) and other advice on how much of each vitamin and mineral the average healthy person needs. The Center for Science in the Public Interest, publisher of Nutrition Action, wants the Food and Drug Administration to require ULs on at least some supplement labels over the next few years. But you needn't wait that long to find out what they are. NAH's Bonnie bon·ny also bon·nie adj. bon·ni·er, bon·ni·est Scots 1. Physically attractive or appealing; pretty. 2. Excellent. Liebman spoke by phone with researcher and physician Robert Russell Robert or Bob Russell may refer to:
Q: What are ULs? A: The UL is the highest level of a vitamin or mineral that can be safely taken without any risk of adverse effect. Just going a little bit above the UL is not going to harm most people, but as you get higher and higher, you're increasing your risk of side effects Side effects Effects of a proposed project on other parts of the firm. . Q: So a person who consumes the UL is not in danger? A: No. But to protect the population as much as possible, we don't advise taking more than the UL on a daily basis. We're not talking about the occasional time when you might exceed it. That's not something we worry about. Nor do we worry about people who take more than the UL under a doctor's supervision or as part of a clinical trial. And for the most part, we're not talking about toxicity toxicity /tox·ic·i·ty/ (tok-sis´i-te) the quality of being poisonous, especially the degree of virulence of a toxic microbe or of a poison. from food. With the possible exception of vitamins A and D, almost all of the cases of toxicity are based on taking supplements or fortified fortified (fôrt  ´fīd),adj containing additives more potent than the principal ingredient. foods. Q: How did the panels come up with the ULs? A: We studied toxicity reports in the literature. We tried to get them as clean as possible. For example, if you're looking at liver toxicity, you want to make sure that the patients did not also have alcohol abuse or hepatitis hepatitis (hĕp'ətī`tĭs), inflammation of the liver. There are many types of hepatitis. Causes include viruses, toxic chemicals, alcohol consumption, parasites and bacteria, and certain drugs. . You want to rule those things out as much as possible, so you can attribute the adverse effect to the large doses of the nutrient and nothing else. Q: And you set the ULs well below those levels? A: Yes. Wherever possible, we'd start with a No Observed Adverse Effect Level no observed adverse effect level Toxicology The concentration of a chemical in a study, or group of studies, that produces no statistically or biologically significant ↑ in frequency or severity of adverse effects between an exposed population and an , or LOAEL LOAEL Lowest Observed Adverse Effect Level . If you know that people took X amount--say 100 milligrams--and there was no toxicity in any individuals, that would be a LOAEL. If you had no LOAEL, you could use a Lowest Observed Adverse Effect Level, or LOAEL. If several people had some sign of toxicity at 100 milligrams, that would be a LOAEL. With a LOAEL, we'd use a greater safety factor to bring the level down further. Q: So there's always a safety margin. A: Yes. The so-called "uncertainty factor" is built into the UL to protect almost all of the population. We divide the NOAEL NOAEL, n ‘no-observed-adverse-effect-level,’ the maximum concentration of a substance that is found to have no adverse effects upon the test subject. or LOAEL by the uncertainty factor. So if a study finds a LOAEL of 100 mg, and you use an uncertainty factor of two, the UL would be 50 mg. If you have only a few case reports of toxicity instead of a whole series of people, you would use a larger safety factor, because you don't really have a good handle on what the upper level should be. Q: Why are some ULs based on relatively minor side effects, like diarrhea diarrhea (dīərē`ə), frequent discharge of watery feces from the intestines, sometimes containing blood and mucus. It can be caused by excessive indulgence in alcohol or other liquids or foods that prove irritating to the stomach or for vitamin C vitamin C or ascorbic acid Water-soluble organic compound important in animal metabolism. Most animals produce it in their bodies, but humans, other primates, and guinea pigs need it in the diet to prevent scurvy. ? A: ULs are based on the earliest side effects to occur--not necessarily the most serious ones. But that doesn't mean that there are no serious side effects. For example, flushing Flushing, part of Queens, New York City, United States Flushing, former village, now in N Queens borough of New York City, SE N.Y.; chartered 1645, inc. into Greater New York City with Queens in 1898. is the most sensitive indicator of niacin niacin: see coenzyme; vitamin. niacin or nicotinic acid or vitamin B3 Water-soluble vitamin of the vitamin B complex, essential to growth and health in animals, including humans. excess. But if people take a much higher dose--like 3,000 to 5,000 mg of niacin a day--to lower their cholesterol, they can get severe liver disease Liver Disease Definition Liver disease is a general term for any damage that reduces the functioning of the liver. Description The liver is a large, solid organ located in the upper right-hand side of the abdomen. . We use the most conservative indicator because the ULs are meant to protect the general population. Then we can feel confident that if you take that level on a daily basis, it's safe. GETTING Too MUCH Q: Which nutrients most concern you? A: The UL for vitamin A vitamin A also called retinol Fat-soluble alcohol, most abundant in fatty fish and especially in fish-liver oils. It is not found in plants, but many vegetables and fruits contain beta-carotene (see from retinol retinol: see Vitamin A under vitamin. is 10,000 IU. You can find single-nutrient supplements with 25,000 IU of vitamin A in any health-food store. You can put yourself in danger by taking those on a daily basis. And children are better off with a daily multi that has no more than the UL for vitamin A, which is 3,000 IU for 4- to 8-year-olds and 2,000 IU for younger children. Those ULs assume that all of the vitamin A in the supplement comes from retinyl palmitate Retinyl palmitate, or vitamin A palmitate, is a common vitamin supplement, with formula C36H60O2. It is available in both oral and injectable forms for treatment of vitamin A deficiency, under the brand names Aquasol A® and Palmitate A®. or other forms of retinol, not from beta-carotene or other carotenoids Carotenoids Carotenoids are yellow to deep-red pigments. Mentioned in: Vitamin A Deficiency carotenoids (k , which have no UL because there is insufficient evidence insufficient evidence n. a finding (decision) by a trial judge or an appeals court that the prosecution in a criminal case or a plaintiff in a lawsuit has not proved the case because the attorney did not present enough convincing evidence. of toxicity. Q: What does too much vitamin A do? A: In women who are capable of becoming pregnant, the risk is birth defects birth defects, abnormalities in physical or mental structure or function that are present at birth. They range from minor to seriously deforming or life-threatening. A major defect of some type occurs in approximately 3% of all births. . In the rest of the population, it's irreversible irreversible (ir´ēvur´seb  l),adj incapable of being reversed or returned to the original state. liver disease. We're talking about severe, fibrotic Fibrotic Pertaining to or characterized by fibrosis. In dermatological description, "fibrotic" would be used to describe leathery, bound-down, or thickened, scarred skin. Mentioned in: Lymphedema , cirrhotic cir·rho·sis n. 1. A chronic disease of the liver characterized by the replacement of normal tissue with fibrous tissue and the loss of functional liver cells. liver disease, not just elevated liver enzymes. Q: Are the elderly at greater risk? A: We can't say for certain. When the elderly consume vitamin A, they clear it from the blood and store it in the liver less efficiently than younger people. And we have customarily taken those higher blood levels as a sign of overload See information overload and overloading. , so it makes sense that the elderly would be more prone to toxicity. But we don't have evidence that they actually develop liver toxicity more often. Q: What other nutrients might we get too much of? A: Some single-nutrient supplements exceed the UL for zinc zinc, metallic chemical element; symbol Zn; at. no. 30; at. wt. 65.38; m.p. 419.58°C;; b.p. 907°C;; sp. gr. 7.133 at 25°C;; valence +2. Zinc is a lustrous bluish-white metal. It is found in Group 12 of the periodic table. . And we're a bit worried about excess folic acid folic acid: see coenzyme; vitamin. folic acid or folate Organic compound essential to animal growth and health and needed by bacteria as a growth factor. . You wouldn't get it from a single supplement, but if you were also eating a number of fortified foods, you might exceed the UL for folic acid, which is 1,000 micrograms a day. That could cover up or precipitate precipitate /pre·cip·i·tate/ (-sip´i-tat) 1. to cause settling in solid particles of substance in solution. 2. a deposit of solid particles settled out of a solution. 3. occurring with undue rapidity. a vitamin B-12 deficiency. Q: Can't a blood test tell people if they're low in B- 127 A: Yes, but from a public health point of view, we don't want to depend on that. There is actually a debate over whether to fortify for·ti·fy v. for·ti·fied, for·ti·fy·ing, for·ti·fies v.tr. To make strong, as: a. To strengthen and secure (a position) with fortifications. b. To reinforce by adding material. the food supply with vitamin B-12, which would help prevent deficiencies. There are no reports of B-12 toxicity, so there's no UL. It's safe. Q: Can people take unlimited quantities of nutrients that have no ULs? A: No. It may just mean that the data don't exist. For example, there's no UL for arsenic arsenic (är`sənĭk), a semimetallic chemical element; symbol As; at. no. 33; at. wt. 74.9216; m.p. 817°C; (at 28 atmospheres pressure); sublimation point 613°C;; sp. gr. (stable form) 5.73; valence −3, 0, +3, or +5. , which may be a nutrient we need in tiny quantities. We know that some kinds of arsenic are poisonous poi·son·ous adj. Relating to or caused by a poison. poisonous having the properties of a poison. poisonous bride's bush pavettaschumanniana. and that the kind found in drinking water drinking water supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g. may raise the risk of cancer. But there's no data on toxicity from the kind of arsenic found in food. GETTING TOO LITTLE Q: The Academy also updated the Recommended Dietary Allowances. Why is the new RDA RDA abbr. recommended daily allowance Recommended Dietary Allowance (RDA) The Recommended Dietary Allowances (RDAs) are quantities of nutrients in the diet that are required to maintain good health in people. for B-12 so low? A: I used to recommend 25 micrograms a day to play it safe for people with atrophic gastritis atrophic gastritis n. Chronic gastritis with atrophy of the mucous membrane and destruction of the peptic glands. atrophic gastritis , a problem for 10 to 30 percent of people older than 50. They produce too little stomach acid to extract B-12 when it's bound to proteins in food. We now know that most people with atrophic gastritis can absorb enough B-12 by taking 2.4 micrograms a day, the new RDA, as long as it's in an unbound unbound said of electrolytes, e.g. iron and calcium, and other substances which are circulating in the bloodstream and are not bound to plasma proteins so that they are available immediately for metabolic processes. See also calcium, iron. form--that is, in a fortified food or a supplement. Q: B-12 is the first supplement the Academy has told people to take? A: Yes. If you're older than 50, you need at least 2.4 mcg of B-12 from a supplement or a fortified food like breakfast cereal breakfast cereal, a food made from grain, commonly eaten in the morning. The oldest type of cereal, known as porridge or gruel, requires cooking in water or milk. The modern breakfast cereals, however, are entirely precooked and eaten in cold milk. . Q: Most multis have less than the RDA for vitamin K vitamin K Any of several fat-soluble compounds essential for the clotting of blood. A deficiency of vitamin K in the body leads to an increase in clotting time. In 1929 a previously unrecognized fat-soluble substance present in green leafy vegetables was found to be required . Is that a problem? A: It's too early to say. The question is how vitamin K affects bone. We know that certain markers in the blood go up in people who are vitamin-K-deficient, but there just wasn't enough evidence to say if that raises their risk of bone fracture fracture, breaking of a bone. A simple fracture is one in which there is no contact of the broken bone with the outer air, i.e., the overlying tissues are intact. In a comminuted fracture the bone is splintered. . The beauty of these new RDAs is that once a critical mass of evidence comes in, they can be revised. We used to have to wait 10 to 15 years. The RDA for vitamin D vitamin D Any of a group of fat-soluble alcohols important in calcium metabolism in animals to form strong bones and teeth and prevent rickets and osteoporosis. It is formed by ultraviolet radiation (sunlight) of sterols (see steroid) present in the skin. , for example, might be raised fairly soon for people over 70. Even though their RDA is high--600 IU a day--that may not be sufficient. Q: Why? A: The skin of older people is much less able to make vitamin D. People in their 70s make roughly half as much vitamin D as children can make from the same ultraviolet An invisible band of radiation at the upper end of the visible light spectrum. With wavelengths from 10 to 400 nm, ultraviolet starts at the end of visible light and ends at the beginning of X-rays. The primary source of ultraviolet light is the sun. sun exposure. And older people's bodies are less able to convert vitamin D to the active form. Plus the older gut gut (gut) 1. intestine. 2. the primordial digestive tube, consisting of the fore-, mid-, and hindgut. 3. surgical g. blind gut cecum. has fewer vitamin-D receptors, so you have a malabsorption malabsorption /mal·ab·sorp·tion/ (mal?ab-sorp´shun) impaired intestinal absorption of nutrients. mal·ab·sorp·tion n. Defective or inadequate absorption of nutrients from the intestinal tract. problem. All that adds up to a significant increase in an older person's requirement. Q: And the RDA assumes that you get no vitamin D from the sun? A: Yes. Some people may get enough from sunlight. But the RDAs are meant to protect the entire population. And in northern latitudes--say, in Boston--the sun isn't strong enough in the winter for your body to make enough vitamin D. That's true across the northern states and Canada. In the southern states Southern States U.S. Confederacy government of 11 Southern states that left the Union in 1860. [Am. Hist.: EB, III: 73] Dixie popular name for Southern states in U.S. and for song. [Am. Hist. , older people may go out in the sun more. But many don't, and many use sunscreen sunscreen /sun·screen/ (-skren) a substance applied to the skin to protect it from the effects of the sun's rays. sun·screen n. , which blocks the UV rays. So they might need to take vitamin D anyway. Q: Yet the National Academy of Sciences didn't recommend that older people take a supplement? A: No, but its report definitely implies that you need one for both vitamin D and calcium. Even when older people eat a healthy diet, they're not likely to meet those requirements. That's particularly true for vitamin D. It would take a quart and a half of milk a day to meet the current RDA for people over 70, which is 600 IU. Nobody's going to drink that much. You won't see RDAs on food and supplement labels, because the numbers vary for men and women, young and old. Instead, labels list Daily Values (DVs), though supplements can also call them U.S. Recommended Daily Allowances (or USRDAs). For each nutrient, the DV (or USRDA USRDA United States Recommended Daily Allowance ) is a single number that is set high enough to protect almost everyone.
VITAMINS
Nutrient Recommended Daily
(other names) Dietary Value
Allowance (DV)
(RDA)
Vitamin A Women: 700 mcg 5,000 IU(1)
(retinol) Men: 900 mcg (1,500 mcg)
Carotenoids None. (NAS advises None
(alpha-carotene, eating more cartotenoid-
beta-carotene rich fruits and
beta-cryptoxanthin, vegetables).
lutein, lycopene,
zeaxanthin)
Thiamin Women: 1.1 mg 1.5 mg
(vitamin B-1) Men: 1.2 mg
Riboflavin Women: 1.1 mg 1.7 mg
(vitamin B-2) Men: 1.3 mg
Niacin Women: 14 mg 20 mg
(vitamin B-3) Men: 16 mg
Vitamin B-6 Ages 19-50:1.3 mg 2 mg
(pyridoxine) Women 50+: 1.5 mg
Men 50+: 1.7 mg
Vitamin B-12 2.4 mcg 6 mcg
(cobalamin)
Folate 400 mcg 400 mcg
(folacin, folic acid) (0.4 mg)
Vitamin C Women: 75 mg 60 mg
(ascorbic acid) Men: 90 mg
(Smokers: add 35 mg)
Vitamin D Ages 19-50: 200 IU(3) 400 IU
Ages 51-70: 400 IU(3)
Over 70: 600 IU(3)
Vitamin E 15 mg 30 IU
(alpha-tocopherol) (33 IU--synthetic) (synthetic)
(22 IU--natural)
Vitamin K Women: 90 mcg(3) 80 mcg
phylloquinone Men: 120 mcg(3)
MINERALS
Calcium Ages 19-50: 1,000 mg(3) 1,000 mg
Over 50: 1,200 mg(3)
Chromium Women: 20-25 mcg(3) 120 mcg
Men: 30-35 mcg(3)
Copper 900 mcg 2 mg
(2,000 mcg)
Iron Women 19-50: 18 mg 18 mg
Women 50+: 8 mg
Men: 8 mg
Magnesium Women: 310-320 mg 400 mg
Men: 400-420 mg
Phosphorus 700 mg 1,000 mg
Selenium 55 mcg 70 mcg
Zinc Women: 8 mg 15 mg
Men: 11 mg
VITAMINS
Nutrient Good Upper
(other names) Sources Level
(UL)
Vitamin A Liver, fatty fish, fortified 10,000 IU
(retinol) foods (milk, breakfast (3,000 mcg)
cereals, etc.).
Carotenoids Orange fruits & vege- None. Panel
(alpha-carotene, tables (alpha- and beta- said don't
beta-carotene carotene), green leafy take beta-
beta-cryptoxanthin, vegetables (beta-caro- carotene,
lutein, lycopene, tene and lutein), tomatoes except to
zeaxanthin) (lycopene). get RDA for
vitamin A.
Thiamin Breads, cereals, pasta, None
(vitamin B-1) & foods made with
"enriched" or whole-grain
flour; pork.
Riboflavin Milk, yogurt, foods None
(vitamin B-2) made with "enriched"
or whole-grain flour.
Niacin Meat, poultry, seafood, 35 mg(2)
(vitamin B-3) foods made with
"enriched" or whole-
grain flour.
Vitamin B-6 Meat, poultry, seafood, 100 mg
(pyridoxine) fortified foods (cereals, etc.),
liver.
Vitamin B-12 Meat, poultry, seafood, None
(cobalamin) dairy foods, fortified foods
(cereals, etc.).
Folate Orange juice, beans, 1,000
(folacin, folic acid) other fruits & vegetables, mcg(2)
fortified cereals, foods (1 mg)
made with "enriched"
or whole-grain flour.
Vitamin C Citrus & other fruits, 2,000 mg
(ascorbic acid) vegetables, fortified
foods (cereals, etc.).
Vitamin D Sunlight, fatty fish, 2,000 IU
fortified foods (milk,
breakfast cereals, etc.).
Vitamin E Oils, whole grains, nuts. 1,000 mg(2)
(alpha-tocopherol) (1,100 IU--
synthetic)
(1,500 IU--
natural)
Vitamin K Green leafy vegetables, None
phylloquinone oils.
MINERALS
Calcium Dairy foods, fortified 2,500 mg
foods, leafy green
vegetables, canned fish
(eaten with bones).
Chromium Whole grains, bran cereals, None
meat, poultry, seafood.
Copper Liver, seafood, nuts, 10 mg
seeds, wheat bran, (10,000
whole grains, chocolate. mcg)
Iron Red meat, poultry, 45 mg
seafood, foods made with
"enriched" or whole-grain
flour.
Magnesium Green leafy vegetables; 350 mg(2)
whole-grain breads,
cereals, etc.; nuts.
Phosphorus Dairy foods, meat, poultry, Ages 19-70
seafood, foods (processed 4,000 mg
cheese, colas, etc.) made Over 70:
with phosphate additives. 3,000 mg
Selenium Seafood, meat, poultry; 400 mcg
grains (depends on
levels in soil).
Zinc Red meat, seafood, 40 mg
whole grains, fortified
foods (cereals, etc.).
VITAMINS
Nutrient Selected Nutrition Action
(other names) Adverse Comments
Effects
Vitamin A Liver toxicity, The body turns
(retinol) birth defects, some carotenoids
Inconclusive: into vitamin A.
bone loss
Carotenoids Smokers who Lutein may lower
(alpha-carotene, took high doses risk of cataracts
beta-carotene of beta-carotene and degeneration
beta-cryptoxanthin, supplements of the retina.
lutein, lycopene, (33,000-50,000 IU Lycopene may
zeaxanthin) a day) had higher lower risk of
risk of lung cancer. prostate cancer.
Thiamin None reported.
(vitamin B-1)
Riboflavin None reported. May lower risk
(vitamin B-2) of cataracts.
Niacin Flushing (burning, Cholesterol-lowering
(vitamin B-3) tingling, itching, doses of niacin should
redness), liver only be taken under
damage. a doctor's supervision.
Vitamin B-6 Reversible nerve May lower risk
(pyridoxine) damage (burn- of heart disease
ing, shooting, (by lowering
tingling pains, homocysteine
numbness, etc.). levels).
Vitamin B-12 None reported. People over 50
(cobalamin) need a supplement
or fortified food.
Folate Can mask or Reduces risk of
(folacin, folic acid) precipitate a birth defects. May
B-12 deficiency, lower risk of heart
which can cause disease, cervical
irreversible nerve and colon cancer,
damage. and depression.
Vitamin C Diarrhea. High doses (1,000
(ascorbic acid) mg a day) may
shorten colds.
Vitamin D High blood calcium, Deficiency can
which may cause cause bone loss
kidney and heart and may raise risk
damage. of osteoporosis.
Vitamin E Hemorrhage. May lower risk of
(alpha-tocopherol) heart disease,
prostate cancer,
cataracts; may
slow Alzheimer's.
Vitamin K Interferes with May lower
phylloquinone coumadin & other risk of bone
anti-clotting drugs. fractures.
MINERALS
Calcium High blood May lower risk of
calcium, which osteoporosis, colon
may cause kidney cancer. High doses
damage, kidney (2,000 mg a day) may
stones. raise risk of prostate
cancer.
Chromium Inconclusive: May lower risk
kidney or muscle of diabetes.
damage.
Copper Liver damage.
Iron Gastrointestinal Gene raises risk
effects (constipa- of iron overload
tion, nausea, (hemochromatosis)
diarrhea). in some people.
Magnesium Diarrhea. May lower risk of
osteoporosis,
heart disease, or
high blood pressure.
Phosphorus High blood With phosphate
phosphorus, additives on the rise,
which may look for low-, not
damage kidneys high-phosphorus
and bones. multivitamins.
Selenium Nail or hair May lower risk
loss or brittleness. of prostate, lung,
colon cancer.
Zinc Lower copper levels, The average person
HDL ("good") gets about a
cholesterol, and quarter of the UL
immune response. from food.
Recommended Dietary Allowance (RDA): We list RDAs for
adults only.
Daily Value (DV): These levels, also called U.S. Recommended
Daily Allowances (or USRDAs), appear on food and supplement
labels. Unlike the RDAs, there is only one Daily Value for everyone
over age tour.
Tolerable Upper Intake Level (UL): These levels are upper safe
daily limits We list ULs for adults only.
Selected Adverse Effects: What happens if you take too much.
The UL is based on the adverse effect listed in italics. "Inconclusive"
adverse effects are based on inconsistent or sketchy evidence.
Other Tolerable Upper Intake Levels
Boron: 20 mg Manganese: 11 mg
Choline: 3.5 grams Molybdenum: 2,000 mcg (2 mg)
Flouride: 10 mg Nickel: 1 mg
Iodine: 1,100 mcg (1.1 mg) Vanadium: 1.8 mg
(1) We get vitamin A both from retinal and carotenoids, but this number
assumes that all of the vitamin A comes from retinal.
(2) From supplements and fortified foods only.
(3) Adequate Intake(AI). The National Academy of Sciences (NAS)
had too little data to set an RDA.
Robert Russell is Associate Director of the Jean Mayer Jean Mayer (February 19, 1920 – January 1, 1993) was a renowned French-American nutritionist and the tenth president of Tufts University from 1976 to 1992. During his lifetime, Mayer was known as a leading expert and activist on hunger issues. U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University Tufts University, main campus at Medford, Mass.; coeducational; chartered 1852 by Universalists as a college for men. It became a university in 1955. Jackson College, formerly a coordinate undergraduate college for women, merged with the College of Liberal Arts in in Boston. |
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