The Issue
The Fats Subcommittee of the Dietary Guidelines Advisory
Committee, led by Dr. Penny Kris-Etherton, has recommended to the full
committee that the 2005 Dietary Guidelines for Americans include a
guideline that Americans include 8 to 9 ounces of fatty fish per week in
their diets, presumably to achieve adequate intake of omega-3 fatty acids
and reduce the risk of heart disease. Although diets rich in fatty fish,
as compared to red meat, have been shown to be associated with less
cardiovascular risk, fish and shellfish often contain unsafe levels of
contaminants. Fish is also high in animal protein, and often, in saturated
fat and cholesterol. Omega-3 fatty acids are readily available in plant
foods that do not have these attendant disadvantages.
The Food and Drug Administration (FDA) and the
Environmental Protection Agency (EPA) recently issued a joint statement
warning pregnant women, women who may become pregnant, breastfeeding
women, and children to limit the consumption of fatty fish because of the
potential effects of mercury and organochlorine toxicity. Given the high
levels of mercury, organochlorines, and other environmental toxins that
accumulate in fish, and in view of our nation�s already
animal-protein-heavy diets, a recommendation to consume two to three
portions of fish weekly is likely to do far more harm than good.
Understanding Mercury
Mercury is a global pollutant that comes from both
natural and human-generated sources. Naturally occurring mercury is
present in rock and soils. Combustion of fossil fuels is the main way
mercury is released into the environment. Medical and municipal waste
incinerators and coal-fired utility plants contribute much of the mercury
released into the atmosphere. Once released, mercury can travel long
distances and pollute the air, water, and food supply.1
In the environment, mercury exists in its elemental form
and in a variety of organic forms. One of these organic forms,
methylmercury, accumulates up the food chain in aquatic systems,
concentrating especially in large predatory fish. The potential sources of
mercury contamination for the general population are consumption of water
or food stuffs contaminated with mercury, inhalation of mercury-containing
vapors, and exposure to dental amalgams or medical treatments that contain
mercury. Of these, the consumption of fish and shellfish contributes most
to the methylmercury concentration in humans.1
Nearly all fish contain traces of methylmercury. Some
fish and shellfish tend to contain higher levels either because they live
in more contaminated waters or because they are larger carnivores
consuming many contaminated smaller fish. Because mercury is eliminated
slowly from the body, it may build to very high levels in the systems of
animals�including humans�that consume it.
Shark, swordfish, king mackerel, and tile fish are known
to have especially high concentrations of methylmercury (mean of samples
tested: 0.73, 0.99, 0.97, and 1.45 parts per million (ppm), respectively).
Other commonly eaten fish also contain high levels of methylmercury
(between 0.25 and 0.55 ppm): bass, bluefish, grouper, halibut, lobster,
marlin, orange roughy, canned albacore tuna, and fresh tuna. Some fish
have more modest amounts on average (less than 0.1 ppm); these include
anchovies, catfish, clams, cod, crab, haddock, perch, pollock, salmon,
scallops, shrimp, and trout.2
Levels of contamination vary widely. Among tuna, for
example, there is a three-fold difference in mean levels of contamination
between canned light tuna (0.12 ppm) and canned albacore tuna (0.35 ppm)
or tuna that is sold fresh or frozen (0.38 ppm).2 Contamination also
varies greatly between individual fish. Therefore, even well-informed
consumers have no way of knowing whether the fish they have purchased has
a high or low level of mercury contamination.
In 2000, the National Research Council convened a group
of scientists to make recommendations on �acceptable� levels of mercury
consumption. This level, known as the exposure reference dose (RfD), is
the level of daily exposure to mercury thought likely to be without risk
of adverse effects for humans (including sensitive subgroups), even if
exposure occurred regularly over a lifetime. This committee set the RfD at
0.1 micrograms (�g) of mercury per kilogram of body weight per day.1 This
means that the weekly RfD would be about 7 �g per week for a toddler,
about 14 �g per week for a five-year-old child, and about 42 �g per week
for a 135-pound woman.3
Specific examples put these numbers in perspective. Two
ounces of canned tuna with .36 ppm would provide 20 �g mercury�nearly
three times the RfD for a toddler. Six ounces, the amount in two tuna
salad sandwiches, would provide 61�g of mercury, which is more than four
times the weekly RfD for a five-year-old; it would also be about 50
percent over the weekly RfD for an adult. Clearly, even modest consumption
of moderately contaminated and commonly eaten fish can put consumers at
risk very quickly.3
It is not surprising that the most recent surveys of
methylmercury contamination (based on data from 1999�2000) found that 7.8
percent of women of childbearing age have blood mercury levels above the
EPA�s �safe� limit of 5.8 �g of mercury per liter. Moreover, 15.7 percent
of women of childbearing age have levels above 3.5 �g/L, which is high
enough to put a fetus or breastfeeding infant at risk.4,5 The EPA
estimates that about 7 million women and children are eating
mercury-contaminated fish at or above levels it considers safe.4 The
bottom line: Significant numbers of Americans are already over-consuming
mercury-laden fish and seafood. It is inadvisable from a public health
perspective to encourage further consumption of this contaminated product.
Effects of Mercury Contamination
Mercury exposure has been linked to a wide variety of
ills, including acute and chronic effects on the cardiovascular and
central nervous systems. Moreover, the EPA and the International Agency
for Research on Cancer (IARC) have designated mercury as a possible human
carcinogen.1 Human occupational studies suggest that methylmercury
exposure alters immune function.1 Methylmercury exposure has also been
shown to affect reproduction.1 In one study, the rate of spontaneous
abortions for wives of mercury-exposed men (with urinary mercury greater
than 50 �g per liter) was double that for controls.6 Some exposure studies
also suggest that fertility may be lower in mercury-exposed individuals.1
Mercury and the heart
Mercury accumulates in the heart, as well as other
tissues, and has been associated with increased blood pressure, irregular
and increased heart rate, and increased rates of death from cardiovascular
disease in at least 12 scientific studies.1
Consumption of fish and omega-3 fatty acids, including
docosahexaneonic acid (DHA) and eicosapentanoic acid, has been associated
with decreased risk of heart attack in individuals consuming a
western-style diet.7,8 However, two recent studies have shown that mercury
exposure may have the opposite effect. In a case-control study conducted
in eight European countries and Israel, the relative risk of first
myocardial infarction (heart attack) for men in the highest quartile of
mercury exposure was 2.16 that of those in the lowest quartile, after
adjustment for DHA levels and cardiovascular disease risk factors. When
comparing patients to controls, the toenail mercury levels were 15 percent
higher among those who had suffered a first heart attack.9 A second study
showed increased risk of cardiovascular mortality with increasing
methylmercury exposure.10
A recent study of 14-year-old children who had been pre-
and postnatally exposed to relatively high levels of methylmercury found
the children were less capable of maintaining the normal variability of
the heart rate necessary to secure adequate oxygen supply to the tissues
(a risk factor for cardiovascular disease and sudden death) as level of
exposure increased.11 This study provides a possible mechanism for
explaining the increased risk of cardiovascular disease in methylmercury-exposed
individuals.
Mercury and the Central Nervous System
Acute methylmercury exposure has been shown to cause
severe neurological dysfunction and developmental abnormalities, including
mental retardation, abnormal reflexes, disturbances in physical growth,
blindness, paralysis, cerebral palsy, and limb deformities in children
whose mothers were exposed to high levels of mercury while they were in
utero.1
Lower-dose chronic exposures also have very serious
effects on the developing central nervous system in children and on the
adult central nervous system. In general, children exposed to mercury show
changes in neurological status and achieve lower scores on developmental
scales, language development tests, IQ tests, visual-spatial skills
scales, and other tests.1 A recent paper showed that some of these
neurodevelopmental effects of prenatal exposure to methylmercury persist
through 14 years of age and thus are likely to be irreversible.12 The
study also found correlations between neurodevelopmental impairments and
post-natal mercury exposure (i.e., the children�s levels of fish
consumption). The most striking finding in this study was that some of the
adverse effects on brain function occurred in children who had exposure
levels well below the RfD.12
Other Bioaccumulative Pollutants in Fish
There are four primary groups of pollutants in addition
to the heavy metal mercury in waterways that accumulate in aquatic animals
in concentrations many times higher than those in the water. Taken
together, polychorinated biphenyls (PCBs), dioxin, chlordane, DDT, and
mercury account for 96 percent of all fish advisories issued in 2002. Many
other toxins, including other heavy metals and organochlorine pesticides,
find their way into water and aquatic life as well.13
These pollutants are toxic to humans, fish, and other
animals that consume and bioaccumulate them. Many of these chemicals are
especially problematic, because they are not readily cleared from the body
and accumulate over a lifetime. Thus, even if exposure is limited to a
discreet period of time, the potential risks persist. According to the
EPA, PCBs are known carcinogens in some species and a probable carcinogen
in humans. PCBs also have been shown to disrupt immune function, cause
learning disabilities, and disrupt neurological development; they may have
endocrine effects as well. Furthermore, children born to women in fishing
villages or exposed through occupational contact with PCBs have lower
birth weight and lower weights for gestational age as PCB exposure level
increases.14 Dioxins, too, are known carcinogens and have also been shown
to cause liver damage, weight loss, and reductions in immune function, and
to have a negative effect on early development and hormone levels.15 At
high doses, human exposure to dioxins can result in a serious skin disease
called chloracne.16 The main route of human exposure to dioxins is
consumption of contaminated foods, especially fish and other products
containing animal fats.17 Chlordane and DDT, an organochlorine, are
pesticides that have been banned from use in the United States.
Nonetheless, appreciable levels of these highly toxic chemicals remain in
our waterways and bioaccumulate in fish.
Recent sources show that contamination with these
pollutants is widespread both globally18 and domestically, especially in
the Great Lakes region and the Eastern seaboard.13,19 In a survey of
skipjack tuna from offshore waters around the world, Japanese researchers
made an astonishing discovery. Organochlorines had contaminated every
liver of every tested tuna, even though the fish came from a wide variety
of locations, including Japan, Taiwan, the Philippines, Indonesia,
Seychelles, and Brazil, as well as the Japan Sea, the East China Sea, the
South China Sea, the Bay of Bengal, and the North Pacific Ocean. That
researchers did not find even one uncontaminated liver illustrates how
pervasive such pollution has become.18
Lessons Learned from Farmed Salmon
A consumer might think that farmed salmon would contain
fewer toxins than sea or lake fish, since farmed fish live in a more
controlled environment. But, at least in the case of salmon, the opposite
is true. Researchers analyzed 2 metric tons of farmed salmon from major
salmon-farming sites around the world for organochlorine contaminants and
found that the levels of these toxic compounds are significantly higher in
farmed than wild salmon.20 Scientists suspect that this concentration of
toxins is caused by the practice of feeding these fish large volumes of
contaminated fish remains.
High-Risk Populations
Women who may become pregnant, pregnant and
breastfeeding women, and children are especially vulnerable to the effects
of environmental toxins that accumulate in fish. Exposure to even low
levels of methylmercury in utero can cause developmental problems and
impairments in motor and visual integration. Other environmental
toxins�such as dioxins, some of which are known carcinogens�are especially
dangerous during fetal development and early childhood.16
According to a new study in the April issue of
Environmental Health Perspectives, women are already eating too much fish;
as a result, as many as one in six newborns has a mercury level above that
considered safe by the EPA. The authors reviewed diet records and tested
the mercury levels in blood of more than 1,700 women (from 1999-2000
NHANES data) and found that those who consumed fish or shellfish two or
more times per week had blood mercury concentrations seven times higher
than those who ate no fish in the previous month.21 Based on the
distribution of blood mercury concentrations noted for various populations
from this study and the number of U.S. births in 2000, the authors
estimates that at least 300,000�and possibly as many as 630,000�newborns
each year in the United States may have been exposed in utero to
methylmercury concentrations sufficiently high to potentially cause
neurodevelopmental problems.21
Toxins Pass from Mother to Child
Scientists and doctors have long known that chemicals
consumed by mothers-to-be are readily passed to the fetus. Such chemicals
are also passed to infants via breast milk. In fact, pollutants such as
mercury show up in higher concentrations in fetal blood than in maternal
blood. A recent report showed that blood mercury levels in a fetus may be
as much as 70 percent higher than in the mother�s levels.3
Infants and small children are often especially
sensitive to the effects of toxins, because of their developing body
systems and their small size; thus, it is essential for mothers to limit
their exposure to toxins as much as possible. Avoiding foods and medicines
known to contain toxins is one important way to do this. More than 20
years ago, when waterways were somewhat less polluted, the breast milk of
vegetarian mothers had only 1 to 2 percent of the national average levels
of certain pesticides and industrial chemicals compared to levels in the
breast milk of omnivorous Americans.22 A second contemporary study found
that the organochlorine contaminants (such as DDT and PCBs) were highest
in the breast milk of fish-eating omnivores, intermediate in omnivores,
and lowest in vegetarians.23
Government Warnings
Recently, the Joint Federal Advisory Panel of the EPA
and the FDA issued its �2004 Consumer Advisory: What You Need to Know
About Mercury in Fish and Shellfish,�24 which gives the following advice
for women who might become pregnant, women who are pregnant, nursing
mothers, and young children:
1. Do not eat Shark, Swordfish, King Mackerel, or
Tilefish because they contain high levels of mercury.
2. Eat up to 12 ounces (2 average meals) a week of a
variety of fish and shellfish that are lower in mercury.
Five of the most commonly eaten fish that are low in
mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
Another commonly eaten fish, albacore ("white") tuna has
more mercury than canned light tuna. So, when choosing your two meals of
fish and shellfish, you may eat up to 6 ounces (one average meal) of
albacore tuna per week.
3. Check local advisories about the safety of fish
caught by family and friends in your local lakes, rivers, and coastal
areas. If no advice is available, eat up to 6 ounces (one average meal)
per week of fish you catch from local waters, but don�t consume any other
fish during that week.
Follow these same recommendations when feeding fish and
shellfish to your young child, but serve smaller portions.
While these warnings may seem sufficiently strict and
detailed at first glance, many scientists and organizations have argued
that they are not strict or clear enough to truly protect the consumer
from harm. Organizations as varied as the Consumers Union, Physicians for
Social Responsibility, Natural Resources Defense Council, and the National
Wildlife Federation joined Michael Bender of the Mercury Policy Project in
signing a letter to the FDA urging better protections for women and
children from exposure to mercury. These organizations argue that current
guidelines do not effectively protect sensitive populations from excess
exposure to methylmercury from fish; they also say that efforts to monitor
mercury levels in the food supply need great improvement.3 For example,
the mercury levels in some types of fish are derived from data collected
in 1978. Even the figures from a 1990�92 FDA survey are likely to be
outdated, since mercury pollution is largely due to industrial combustion
of coal and other human-generated wastes, which may have significantly
increased in scope and volume over the past decade.2
Vas Aposhian, a toxicologist and professor of molecular
and cell biology and pharmacology at the University of Arizona who served
as a key advisor on mercury issues to the FDA and EPA, reported that
mercury levels in albacore tuna are so high consumers should avoid the
fish completely. Dr. Aposhian also criticized the food industry for
exerting influence to weaken mercury warnings.25
Contamination is widespread. The EPA�s fact sheet
�Update: National Listing of Fish and Wildlife Advisories� covering PCBs,
dioxins, mercury, and chlordane notes that as of 2002, 28 states had
statewide advisories. Overall, the 2,800 advisories in the national
listing account for about one-third of the nation�s lakes and about 15
percent of its total river miles; this includes each of the Great Lakes
and their connecting water ways.13 Mercury advisories are especially
common, but New York, Washington, the District of Columbia, and most New
England states also have advisories for PCBs, cadmium, and dioxins.13
Nutrient Composition of Fish
Like other meats, fish are especially dense in animal
protein (15 to 20 grams in a 3-ounce cooked portion). People in the United
States already consume well above the daily value for protein (50 to 65
grams). Protein intake averages about 15 percent of total calories, for a
mean intake of approximately 100 grams per day for men and 70 grams per
day for women.26 Much of this protein comes from animal sources.
Diets containing excessive protein are associated with
increased risk of impaired renal function,27 osteoporosis,28 and
complications of diabetes.29 Promotion of fish products may increase
protein intake and aggravate these risks.
Furthermore, increasing fish intake would likely
increase total fat and saturated fat intake. Although a small amount of
the fat in fish is omega-3s, much of the remaining fat is saturated.
Chinook salmon, for example, derives 55 percent of its calories from fat,
and swordfish derives 30 percent. About one-quarter of the fat in both
types of fish is saturated. Fish and shellfish are also significant
sources of cholesterol. Three ounces of shrimp have 130 milligrams of
cholesterol, while the same amount of bass has 68 milligrams; in
comparison, a 3-ounce steak has about 80 milligrams.30
Safer Sources of Omega-3 Fatty Acids
High levels of toxins, fat, and cholesterol and a lack
of fiber make fish a poor dietary choice. Fish oils have been popularized
as a panacea against everything from heart problems to arthritis. The bad
news about fish oils, though, is that omega-3s in fish oils are highly
unstable molecules that tend to decompose and, in the process, release
free radicals. Research has shown that omega-3s are found in a more stable
form in vegetables, fruits, and beans.31,32
Individuals need to include foods rich in omega-3 fatty
acids in their diets on a daily basis. Alpha-linolenic acid, a common
omega-3 fatty acid, is found in many vegetables, beans, nuts, seeds, and
fruits. It is concentrated in flaxseeds and flaxseed oil and also found in
oils such as canola, soybean, walnut, and wheat germ. Omega-3 fatty acids
can be found in smaller quantities in nuts, seeds, and soy products, as
well as beans, vegetables, and whole grains.33,34 Corn, safflower,
sunflower, and cottonseed oils are generally low in omega-3s. Fish
consumption is by no means the only way to ensure adequate intake of
essential fatty acids.
Conclusion
Given the clear evidence that fish are commonly
contaminated with toxins that have well-known and irreversible damaging
effects on children and adults, public health policy should not encourage
the consumption of fish. The risks are known, and especially for infants
and women of childbearing age, significant.
Even if a fish recommendation were to carry a
carefully-worded warning about how much and what types of fish might
minimize potential risk from mercury toxicity, it would still be
inadvisable. The other risks associated with fish consumption are also
considerable--contamination with other bioaccumulated pollutants and diets
that are already too high in saturated fat and animal protein to protect
consumers from chronic disease. Further, due to the variability in levels
of pollutants among and between species and individual fish, and to the
fact that these toxins accumulate in the tissue of the fish so food safety
practices at home will not reduce risk of contamination, consumers should
not be encouraged to navigate these dangers, which they cannot truly
minimize or control. Therefore, the Physicians Committee for Responsible
Medicine urges the members of the 2005 Dietary Guidelines Advisory
Committee to reconsider the proposed recommendation that Americans consume
8 to 9 ounces of fatty fish per week.
Instead, PCRM�s doctors and dietitians recommend that
the Committee discourage the consumption of fish and shellfish. Other,
more healthful, foods from plant sources offer the full range of essential
nutrients without the toxins and other health risks in fish.
Report compiled by Amy Joy Lanou, Ph.D.
References
1. Committee on the Toxicological Effects of Methylmercury; National
Research Council. Toxicological effects of methylmercury. National Academy
Press, Washington DC, 2000.
2. U.S. Department of Health and Human Services and U.S. Environmental
Protection Agency. Mercury levels in commercial fish and shellfish.
Accessed April 2004 at:
www.cfsan.fda.gov/~frf/sea-mehg.html .
3. Bender, M. Letter to FDA about better protecting women and children
from exposure to mercury. February 24, 2004. Accessed April 2004 at:
www.mercurypolicy.org/new/fdaletter022404.html
4. Mahaffey KR, Clickner RP, Bodurow CC. Blood organic mercury and
dietary mercury intake: National Health and Nutrition Examination Survey,
1999 and 2000. Environ Health Perspect 2004;112:562-70.
5. Schober SE, Sinks TH, Jones RL, Bolger PM, McDowell M, Osterloh J.,
et al. Blood mercury levels in US Children and women of childbearing age,
1999-2000. JAMA 2003;289:1667-74.
6. Cordier S, Deplan F, Mandereau L, Hemon D. Paternal exposure to
mercury and spontaneous abortions. Brit J Ind Med 1991;48:375-81.
7. Hu FGB, Bronner L, Willett WC, Stampfer MK, Rexrode KM, Albert CM,
Hunter D, Manson JE. Fish and omega-3a fatty acid intake and risk of
coronary heart disease in women. JAMA 2002;287:1815-21.
8. Siscovick DS, Raghunathan TE, King I, Weinmann S, Bovbjerg VE, Kushi
L, Cobb LA, Copass MK, Psaty BM, Lelmaitre R, Retzlaff B, Knopp RH.
Dietary intake of long-chain n-3 polyunsaturated fatty acids and the risk
of primary cardiac arrest. Am J Clin Nutr 2000;71:208S-12S.
9. Guallar E, Sanz-Gallardo MI, van't Veer P, Bode P, Aro A, Gomez-Aracena
J, Kark JD, Riemersma RA, Martin-Moreno JM, Kok FJ. Heavy Metals and
Myocardial Infarction Study Group. Mercury, fish oils, and the risk of
myocardial infarction. N Engl J Med. 2002;347:1747-54.
10. Salonen JT, Seppanen K, Nyyssonen K, Korpela H, Kauhanen J, Kantola
M, Tuomilehto J, Esterbauer H, Tatzber F, Salonen R. Intake of mercury
from fish, lipid peroxidation, and the risk of myocardial infarction and
coronary, cardiovascular and any death in eastern Finnish men. Circulation
1995;91:645-55.
11. Grandjean P, Murata K, Budtz-J�rgensen E, Weihe P. Cardiac
autonomic activity in methylmercury neurotoxicity: 14-year follow-up of a
Faroese birth cohort. Pediatrics 2004;144:169-76.
12. Murata K, Weihe P, Budtz-J�rgensen E, J�rgensen PJ, Grandjean P.
Delayed brainstem auditory evoked potential latencies in 14-year-old
children exposed to methylmercury. Pediatrics 2004;144:177-83.
13. United States Environmental Protection Agency. Update: National
listing of fish and wildlife advisories. Fact Sheet EPA-823-F-03-003, May
2003. Accessed April 2004 at:
www.epa.gov.waterscience/fish/ .
14. United States Environmental Protection Agency. Health effects of
PCBs. June 2002. Accessed April 2004 at:
www.epa.gov/opptintr/pcb/effects.html.
15. United States Environmental Protection Agency. Dioxins. April 2004.
Accessed April 2004 at:
www.epa.gov/ebtpages/pollchemicdioxins.html .
16. United States Environmental Protection Agency. Persistent
Bioaccumulative and Toxic (PBT) Chemical Program: Dioxins and furans.
April 2003. Accessed April 2004 at:
www.epa.gov/pbt/dioxins.htm
.
17. United States Environmental Protection Agency. Consumer factsheet
on: Polychlorinated biphenyls. April 2004. Accessed April 2004 at:
www.epa.gov/safewater/dwh/c-soc/pcbs/html .
18. Ueno D, Takahashi S, Tanaka H, Subramanian AN, Fillmann G, Nakata
H, Lam PK, Zheng J, Muchtar M, Prudente M, Chung KH, Tanabe S. Global
pollution monitoring of PCBs and organochlorine pesticides using skipjack
tuna as a bioindicator. Arch Environ Contam Toxicol. 2003;45:378-89.
19. Hicks HE, De Rosa CT. Sentinel human health indicators: to evaluate
the health status of vulnerable communities. Can J Public Health.
2002;93:S57-61.
20. Hites RA, Foran JA, Carpenter DO, Hamilton MC, Knuth BA, Schwager
SJ. Global assessment of organic contaminants in farmed salmon. Science
2004;303:226-9.
21. Mahaffey KR. Methylmercury: Epidemiology Update. Presentation at
the National Forum on Contaminants in Fish, San Diego, January 28, 2004.
Accessed April 2004 at:
http://www.ewg.org/issues_content/mercury/ppt/3
22. Hergenrather J, Hlady G, Wallace B, Savage E. Pollutants in breast
milk of vegetarians. N Engl J Med 1981;304:792.
23. Noren K. Levels of organochlorine contaminants in human milk in
relation to the dietary habits of the mothers. Acta Paediatr Scand.
1983;72:811-6.
24. U.S. Department of Health and Human Services and U.S. Environmental
Protection Agency. What you need to know about mercury in fish and
shellfish. EPA-823-R-04-005, March 2004. Accessed April 2004 at:
www.cfsan.fda.gov/~dms/admehg3.html .
25. Kaufman M. Women, children warned about tuna consumption:
government offers more specific guidelines on mercury in fish. Washington
Post, March 19, 2004. Accessed April 2004 at:
http://www.washingtonpost.com/wp-dyn/articles/A8179-2004Mar19.html .
26. Wright JD, Kennedy-Stephenson J, Wang CY, McDowell MA, Johnson DC.
Trends in Intake of Energy and Macronutrients --- United States,
1971�2000. MMWR 2004;53:80-2. Accessed April 2004 at:
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5304a3.htm .
27. Knight EL, Stampfer MJ, Hankinson SE, Spiegelman D, Curhan GC. The
Impact of Protein Intake on Renal Function Decline in Women with Normal
Renal Function or Mild Renal Insufficiency. Ann Int Med 2003;138:460-7.
28. Feskanich D, Willett WC, Stampfer MJ, Colditz GA. Protein
consumption and bone fractures in women. Am J Epidemiol 1996;143:472-9.
29. Gin H, Rigalleau V, Aparicio M. Lipids, protein intake, and
diabetic nephropathy. Diabetes Metab 2000;26:45-53.
30. Pennington JAT. Bowes and Church�s food values of portions commonly
used. 15th Edition, Harper Perennial, 1989.
31. Odeleye OE, Watson RR. Health implications of the n-3 fatty acids.
Am J Clin Nutr 1991;53:177-8.
32. Kinsella JE. Reply to O Odeleye and R Watson. Am J Clin Nutr
1991;53:178.
33. Hunter JE. n-3 Fatty acids from vegetable oils. Am J Clin Nutr
1990;51:809-14.
34. Mantzioris E, James MJ, Gibson RA, Cleland LG. Dietary substitution
with an alpha-linolenic acid-rich vegetable oil increases eicosapentaenoic
acid concentrations in tissues. Am J Clin Nutr 1994;59:1304-9.
Fair Use Notice: This document may contain copyrighted material whose
use has not been specifically authorized by the copyright owners.
We believe that this not-for-profit, educational
use on the Web constitutes a fair use of the copyrighted material (as
provided for in section 107 of the US Copyright Law). If you wish to use
this copyrighted material for purposes of your own that go beyond fair
use, you must obtain permission from the copyright owner.
