Zinc plays a key role in better aging - supplements helped

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Zinc plays a key role in better aging

It helps maintain the health of older people, can work as an antioxidant

and lowers mortality.

By Bowerman

Special to The Times

November 19, 2007

http://www.latimes.com/features/health/la-he-eat19nov19,1,6645668.story

The path to healthy aging has plenty of signposts -- eat more fruits and

vegetables for their antioxidants, get enough calcium for strong bones,

have a few fish meals a week to protect the heart.

Here's another signpost that may be less familiar: Make sure you consume

enough zinc.

Two studies published this year addressed the role of zinc in maintaining

health in older people. One, a yearlong study of 50 nursing home residents

65 or older found that people with low levels of zinc in the bloodstream

-- defined as 70 micrograms per deciliter or less -- had twice the

incidence of pneumonia and nearly 50% more antibiotic prescriptions over

the year than those with normal zinc status.

The study, conducted by scientists at Tufts University and Boston

University and published last month in the American Journal of Clinical

Nutrition, also found that those who began the study with normal zinc

levels had a 39% lower mortality rate -- from any cause -- than those who

were deficient.

In a second small study, led by Dr. Ananda Prasad at the Wayne State

University School of Medicine, 50 free-living, healthy elderly subjects

were recruited from a senior center to receive either a daily zinc

supplement or placebo for a year to determine if zinc supplementation

offered protection against colds and flu.

By the end of the yearlong study, zinc-takers had significantly higher

zinc levels in the bloodstream and had suffered significantly fewer

infections -- seven cases versus 35 cases in those taking a placebo.

The study also found lower serum levels of a chemical called

malondialdehyde and other signs of oxidative stress (the production of

cell-damaging free radicals) in the group taking supplements, confirming

earlier evidence that zinc can function as an antioxidant.

The study was published in the American Journal of Clinical Nutrition in

March.

Adequate zinc is critical for the production of lymphocytes -- the army of

specialized white cells in the immune system that help defend against

foreign invaders.

Zinc deficiency leads to impaired immunity and thus decreased resistance

to a host of bacterial, viral, fungal and parasitic invaders. Recovery

from illness takes longer when zinc levels are low than when zinc status

is normal.

Men require 11 milligrams of zinc a day, and women require 8 milligrams.

For the most part, this amount can usually be obtained from the diet

through eating foods such as protein-rich meats, fish and poultry.

But the authors of the two recent reports suggest that dietary intake of

zinc in the elderly may be marginal because some older people may find

these foods too expensive or difficult to chew.

Still, even with these restrictions, it's still possible to get adequate

zinc. Dairy products, beans and nuts provide zinc, as do some fortified,

ready-to-eat cereals. Multiple vitamin and mineral supplements can help

meet needs, particularly if the quality of the diet is good to start with.

A recent analysis of food and supplement use from a large survey of

Americans taken by the U.S. Department of Agriculture (known as the USDA's

Continuing Survey of Food Intakes by Individuals) found that supplement

users had better dietary intake of zinc than nonusers.

Among people age 71 and older, 43% of those who shunned supplements

consumed inadequate intake of zinc from foods compared with 29% of

supplement users. And when the amount of zinc supplied from supplements

was factored in, only 5% of supplement users failed to meet the estimated

average requirement.

Poor zinc intake is not just a problem among the elderly. Data from

another large government food intake survey known as NHANES III indicated

that after seniors, teenage females had the lowest zinc intake, with 61%

failing to meet recommendations. Fewer than half of women at any age took

in an adequate amount.

Men, who tend to consume more protein foods, fared better.

If you decide to use supplements, note that zinc and copper compete with

one another for absorption in the digestive tract, so it's wise to take in

about 2 to 3 milligrams of copper per day along with the recommended 8 or

11 milligrams of zinc.

Rather than fussing with individual nutrients, you can take a balanced

vitamin and mineral supplement, which should contain the proper ratio of

zinc to copper.

Bowerman is a registered dietitian and assistant director of the

UCLA Center for Human Nutrition.

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J Am Diet Assoc. 2007 Nov;107(11):1924-9.

The prevalence of low serum zinc and copper levels and dietary habits

associated with serum zinc and copper in 12- to 36-month-old children from

low-income families at risk for iron deficiency.

Schneider JM, Fujii ML, Lamp CL, Lönnerdal B, Zidenberg-Cherr S.

OBJECTIVE: Iron and zinc share common food sources, and children at

risk of iron deficiency may also develop zinc deficiency. We

determined the prevalence of zinc and copper deficiency and examined

factors associated with serum zinc and copper in young children from

low-income families at risk of iron deficiency. DESIGN: A

cross-sectional study design was used to assess serum zinc and copper,

along with an interview-assisted survey to assess factors associated with

serum zinc and copper in a convenience sample. SUBJECTS/SETTING:

Participants were 435 children aged 12 to 36 months recruited from select

clinics of the Special Supplemental Nutrition Program for

Women, Infants, and Children in Contra Costa and Tulare Counties,

California. STATISTICAL ANALYSES PERFORMED: Frequencies were used to

report prevalence. Multiple linear regressions were conducted to

examine factors associated with serum zinc and copper, controlling for

age, sex, and ethnicity. RESULTS: The prevalence of low serum zinc level

(<70 mug/dL [<10.7 mumol/L]) was 42.8%, and low serum copper level (<90

mug/dL [<14.2 mumol/L]) was <1%. Mean+/-standard deviation of serum copper

was 150+/-22 mug/dL (23.6+/-3.5 mumol/L) and 140+/-24 mug/dL (22.1+/-3.8

mumol/L) for anemic and non-anemic children,

respectively (t test, P=0.026). In multiple linear regression

consumption of sweetened beverages was negatively associated with

serum zinc level, and consumption of >15 g/day meat was positively

associated with serum zinc level, whereas current consumption of

breast milk and >15 g/day beans were positively associated with serum

copper level. CONCLUSIONS: The prevalence of low serum zinc

concentration in the sample was high, and warrants further

investigation amongst vulnerable populations.

PMID: 17964312

1: Am J Clin Nutr. 2007 Oct;86(4):1167-73.

Serum zinc and pneumonia in nursing home elderly.

Meydani SN, Barnett JB, Dallal GE, Fine BC, Jacques PF, Leka LS, Hamer DH.

Nutritional Immunology Laboratory, Mayer US Department of Agriculture

Human Nutrition Research Center on Aging at Tufts University, Boston, MA

02111, USA. simin.meydani@...

BACKGROUND: Zinc plays an important role in immune function. The

association between serum zinc and pneumonia in the elderly has not been

studied. OBJECTIVE: The objective was to determine whether serum zinc

concentrations in nursing home elderly are associated with the incidence

and duration of pneumonia, total and duration of antibiotic use, and

pneumonia-associated and all-cause mortality. DESIGN: This observational

study was conducted in residents from 33 nursing homes in Boston, MA, who

participated in a 1-y randomized, double-blind, and placebo-controlled

vitamin E supplementation trial; all were given daily doses of 50% of the

recommended dietary allowance of essential vitamins and minerals,

including zinc. Participants with baseline (n = 578) or final (n = 420)

serum zinc concentrations were categorized as having low (<70 microg/dL)

or normal (>or=70 microg/dL) serum zinc concentrations. Outcome measures

included the incidence and number of days with pneumonia, number of new

antibiotic prescriptions, days of antibiotic use, death due to pneumonia,

and all-cause mortality. RESULTS: Compared with subjects with low zinc

concentrations, subjects with normal final serum zinc concentrations had a

lower incidence of pneumonia, fewer (by almost 50%) new antibiotic

prescriptions, a shorter duration of pneumonia, and fewer days of

antibiotic use (3.9 d compared with 2.6 d) (P <or= 0.004 for all). Normal

baseline serum zinc concentrations were associated with a reduction in

all-cause mortality (P = 0.049). CONCLUSION: Normal serum zinc

concentrations in nursing home elderly are associated with a decreased

incidence and duration of pneumonia, a decreased number of new antibiotic

prescriptions, and a decrease in the days of antibiotic use. Zinc

supplementation to maintain normal serum zinc concentrations in the

elderly may help reduce the incidence of pneumonia and associated

morbidity.

Publication Types:

* Research Support, N.I.H., Extramural

* Research Support, Non-U.S. Gov't

* Research Support, U.S. Gov't, Non-P.H.S.

PMID: 17921398

*

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