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Prenatal zinc supplementation influences lean tissue growth in infants
It has been suggested that maternal zinc intake influences growth in
utero and in the first stages of growth after birth. In a recent study,
researchers assessed the effect of maternal zinc supplementation during
pregnancy as well as its effects on infant growth during the first twelve
months.
A randomized, double-blind, controlled trial of prenatal zinc
supplementation was conducted among women in Lima, Peru between 1995 and 1997.
Women enrolled during the second trimester and were assigned to receive daily
supplements with zinc (15 mg zinc + 60 mg iron + 250 mcg folic acid) or without
zinc (just 60 mg iron + 250 mcg folic acid) through pregnancy to one month after
delivery. At birth, 546 infants were followed for 12 months to assess growth.
Measurements were collected monthly while health status and dietary intake were
monitored weekly.
Infants born to mothers supplemented with zinc had
significantly larger average growth measures beginning at 4 months and
continuing through month 12. Prenatal zinc was associated with greater weight,
calf circumference, chest circumference, and calf muscle area.
In this
population of women, zinc supplementation during pregnancy resulted in children
with better growth measures (which were in turn associated with healthy
increases in lean tissue mass).
American Journal of
Clinical Nutrition, Vol. 88, No. 1, 154-160, July
2008
Nutrition Fact 2:
Question: What are Anti-Oxidants?
Free radicals
(pro-oxidants) are atoms or molecules with unpaired electrons. These
highly reactive substances can be formed in a number of ways, and once
formed they may use their reactivity to damage important cellular
components - such as the cell membrane - or macromolecules like DNA.
This damage can lead to mutation, impaired function, and even cell
death. To minimize potential damage from free radicals, the body
utilizes a defense system of antioxidants.
Antioxidants
are molecules that can safely interact with free radicals and terminate
their reactivity before vital cellular components are damaged. Although
there are several enzyme systems within the body that scavenge free
radicals, the principle micronutrient (vitamin/mineral) antioxidants
are vitamin E, beta-carotene, vitamin C, and selenium. The body cannot
manufacture these micronutrients, so they must be acquired by diet. In
addition, there are many plant-derived nutrients (phytonutrients) that
can act as powerful antioxidants in the human body.
It is
impossible to completely avoid damage from free radicals. Free radicals
arise from sources both inside (endogenous) and outside (exogenous) our
bodies. Oxidants that develop from processes within our bodies form as
a result of normal breathing, metabolism, and inflammation. Exogenous
free radicals form from environmental factors such as pollution,
sunlight, strenuous exercise, smoking, and alcohol. Unfortunately, no
antioxidant system is perfect, so cells and DNA damaged by oxidation
accumulate as we age.
When you look at a wonderful wood
fireplace it usually burns just fine. However, occasionally a spark or
hot cinder shoots and burns a little hole in your carpet. Over the
months and years, you will have a damaged carpet in front of your
fireplace. Look at the fireplace as the furnace of your cell and the
hot cinders as free radicals. Your carpet is your body. Whatever part
of your body wears out first is the type of disease you will
develop. If it is your brain, you could get Alzheimer’s dementia or
Parkinson’s disease. If it is your eyes, you could develop a cataract
or macular degeneration. If it is your arteries, you could develop a
heart attack or stroke.
You are
not defenseless against this process. Antioxidants are like the fine
wire mesh or glass doors you place in front of your fireplace. The
sparks are still going to fly; however, your carpet—your body—is
protected. This is the key. To protect your body, you want enough
antioxidants on board to handle the number of free radicals you
produce. The best way to achieve this goal is to take high-quality, complete and balanced nutritional supplements.
Nutritional
supplements have been used and valued by American consumers ever since
vitamins were first discovered and commercialized, beginning largely in
the early decades of the 20th century.
Multivitamin/mineral
supplements are an effective means of delivering adequate amounts of
essential nutrients to help people achieve their recommended intakes.
The great majority of dietary supplements, including multivitamins, are
safe for regular use. Despite widespread usage, there have been no
specific published reports of toxicity or adverse effects associated
with the proper use of multivitamins.
A series of
well-publicized clinical trials utilizing relatively high doses of
single nutrients or combinations of nutrients (such as vitamin E and/or
beta-carotene) in diseased patients have yielded disappointing results,
and even suggested the presence of harm. However, those trials were
conducted in patients with serious illnesses (such as cancer or
cardiovascular disease), who were on multiple medications, or who were
smokers. The results of these trials should be placed in their proper
context, including the fact that they are not applicable to the
generally healthy population.
Advanced levels of antioxidants
are a common thread among nearly every population found to be less
prone to chronic degenerative disease. As an example, the Japanese -
often cited as an example of longevity - have high levels of fruit,
vegetables, green tea and soy as part of their traditional diet.
Vegetarians have lower levels of heart disease and cancer when compared
to the typical mixed diet, in part due to their generally higher intake
of antioxidants.
While high levels of single nutrients and
foods may pose a risk of danger and toxicity, there is no known unsafe
level of total antioxidants. As far as we can tell, as long as they are
varied and balanced, the more antioxidants the better.
Health benefits of antioxidants
There are many known health benefits of antioxidant intake. Some scientific examples include the following:
Cancer
- People
with high beta-carotene intakes have about one-third the cancer risk as
people with low beta-carotene intakes. (Peto R. Cancer Surveys
1983;2:327-340.)
- People with higher intakes of vitamin
C have about half the risk for many types of cancer when compared to
people with low vitamin C intakes. (Block G. Am J Clin Nutr
1991;53:270S-282S.)
- People with low intakes of several
antioxidants have more DNA damage than people with generous intakes.
(Ames BN. Metat Res 2001;475:7-20.)
- People with the
highest intakes of vitamin C, E, and beta-carotene have a significantly
lower risk of lung cancer. (Yong LC et al. Am J Epidemiol
1997;146:231-43.)
- Men who took vitamin E supplements
for 10 years or more had a 30% lower risk of bladder cancer. (Michaud
DS et al. Am J Epidemiol 2000;152:1145-53.)
- There are
over 66 studies showing cancer-prevention activity of green tea, black
tea, and their constituents. These include cancer reduction in the
skin, lung, oral cavity, esophagus, stomach, liver, pancreas, bladder,
small intestine, colon and prostate. (Lambert JD et al. Am J Clin Nutr
2005;81:284S-291S.)
Heart Disease
- Elderly
people who took both vitamin C and vitamin E supplements had a
decreased risk of death from heart disease as well as overall
mortality. (Losonczy KG, Harris TB, Havlik RJ. Am J Clin Nutr
1996;64:190-196.)
- Men who took vitamin supplements had
a 70% lower risk of dying from heart disease and a 50% lower risk of
heart attack. (Meyer F, Bairati I, Dagenasis GR. Can J Cardiol
1996;12:930-934.)
- In the Nurses' Health Study
involving over 87,000 women, there was a 41% reduction in risk of heart
disease for those who took vitamin E for more than two years. (Stampfer
MJ, Hennekens CH, Manson JE, et al. New Engl J Med 1993;328:1444-1449.)
- In the Nurses' Health Study, vitamin C supplements were
also related to a lower risk of heart disease. (Osganian SK et al. J Am
Coll Cardiol 2003;42:246-52.)
- In the Health
Professionals Follow-Up Study involving almost 40,000 men, there was a
37% reduction in risk of heart disease in men who took vitamin E for
more than two years. The average intake in the lowest risk group was
400 IU per day. (Rimm EB, Stampfer MJ. Ascherio A, et al. New Engl J
Med 1993;328:1450-1456.)
- To date, 17 human group
studies have been published on flavonoid intake and the risk of
coronary artery disease and stroke. Positive studies have shown
reduction in mortality risk of up to 65%. (Arts ICW and Hollman PCH. Am
J Clin Nutr 2005;81:317S-325S.)
- The largest and
longest study to date, done as part of the Harvard-based Nurses' Health
Study and Health Professionals Follow-up Study, included almost 110,000
men and women whose health and dietary habits were followed for 14
years. The higher the average daily intake of fruits and vegetables,
the lower the chances of developing cardiovascular disease. Compared
with those in the lowest category of fruit and vegetable intake (less
than 1.5 servings a day), those who averaged 8 or more servings a day
were 30% less likely to have had a heart attack or stroke. (Joshipura
KJ, et al. Ann Intern Med 2001 Jun 19;134(12):1106-14.)
Other Chronic diseases
- Several
long-term studies have shown a reduced risk of cataracts in those who
have taken vitamin C and/or vitamin E supplements for more than 10
years. (Jacques PF et al. Arch Ophthalmol 2001;119:1009-19.)
- The
Age-Related Eye Disease Study (AREDS) at NIH found that daily
supplementation with antioxidants, zinc, and copper delayed progression
of age-related macular degeneration. (AREDS report no. 8. Arch
Ophthalmol 2001;119:1417-36.)
- Research has shown a
significant relationship between flavonoid intakes and the occurrence
of asthma. (Knekt P et al. Am J Clin Nutr 2002;76:560-8.)
- Other
research suggests antioxidants may help support lung function and
protect the lungs from oxidative damage. (Schunemann HJ et al. Am J
Respir Crit Care Med 2001;163:1246-55.)
- In a study on
Alzheimer's disease, high levels of vitamin E delayed progression of
the disease. (Sano M et al. N Engl J Med 1997;336:1216-22.)
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