Eggs Get Hype for Helping Older
People in Weight Loss and Risk of Vision Loss
December 1, 2004
Eggs, which not long ago were taking a beating in nutrition
circles, are touted today in the Journal of the American
College of Nutrition as helping older women in weight
loss and reducing the risk of cataract and age-related
macular degeneration (AMD).
Leucine, an essential amino acid found in high quality
protein like eggs, potentially provides a weight loss
advantage during dieting by helping to reduce loss of
lean tissue, promote loss of body fat, and stabilize
blood glucose levels.
The study, which investigated the efficacy of two 1,700-calorie
weight loss diets among women aged 45 to 57 years, found
that women who ate the higher protein breakfast foods
including eggs, low fat dairy and lean meats (containing
10 grams leucine daily) lost slightly more weight, but
of the weight lost, nearly twice as much was fat compared
to those eating a carbohydrate rich breakfast (containing
5 grams leucine daily).
In another paper published in the JACN supplement,
research shows that two antioxidants, lutein and zeaxanthin,
may significantly reduce the risk of cataract and age-related
macular degeneration (AMD).
In the research, eggs are cited as an important dietary
source of leucine as well as lutein and zeaxanthin and,
in the case of the latter two, research shows lutein
and zeaxanthin in eggs to be more bioavailable than
from other food sources.
High Quality Protein Promotes Weight Loss
"We found that increasing high-quality protein
in the diet, like that found in eggs, dairy products
and meats, provides a metabolic advantage due to a high
content of the branched chain amino acid (BCAA) leucine,"
says article author Donald K. Layman, Ph.D., Professor
of Nutrition, Department of Food Science and Human Nutrition
and Department of Internal Medicine, College of Medicine,
University of Illinois at Urbana-Champaign. According
to Layman, both the amount of high quality protein consumed,
as well as the time of day it is consumed, may play
an important role in weight loss.
Layman found that unlike other essential amino acids,
leucine plays several key roles in metabolism. "Leucine
is key to the metabolic advantage of a higher protein
diet because of its unique roles in regulation of muscle
protein synthesis and insulin signaling," says
Layman. According to his research, eating more protein
rich foods like eggs and limiting carbohydrates helps
burn body fat and control hunger and cravings, leading
to weight loss.
When limiting calories, Layman recommends daily intake
of protein above 1.5 g/kg of body weight (or above 102
grams of protein daily for a 150-pound person); whereas
the current Dietary Reference Intake (DRI) for protein
is about half that, set at 0.8 g/kg of body weight (or
55 grams of protein daily for a 150-pound person).
Layman's research also suggests that increased use
of high quality protein at breakfast, in particular,
maybe important for the weight loss advantage of a higher
protein diet. In a 10-week study, Layman showed that
eating a high quality protein breakfast while losing
weight helps maintain lean muscle mass, which is critical
to long-term weight loss and maintenance.
According to Layman, the findings may provide hope
to those battling obesity,
which has been linked to increased risk of diabetes,
heart disease and other chronic diseases.
Eggs Promote Eye Health
The article concerning vision is a review paper discussing
two antioxidants, lutein and zeaxanthin, and the protective
role they play in reducing the risk of cataract and
age-related macular degeneration (AMD).
"Lutein and zeaxanthin, are concentrated in the
macular region of the retina and the eye lens, where
they protect the eye from harmful ultraviolet light,"
says article author Jeffrey Blumberg, Ph.D., Professor
of Nutrition and Senior Scientist at the USDA Human
Nutrition Research Center on Aging at Tufts University.
Blumberg says studies have shown that diets rich in
lutein may cut the risk of cataracts by up to 20 percent
and age-related macular degeneration by up to 40 percent.
Although broccoli, kale and other dark green leafy vegetables
are good sources of lutein, one egg yolk provides approximately
200 micrograms of lutein, and studies have shown that
lutein from eggs is 200 to 300 percent more bioavailable
than lutein from vegetable sources.
Cataracts are the leading cause of blindness in the
world and affect more than 20 million Americans age
65 and older. Age-related macular degeneration is the
leading cause among seniors of irreversible blindness
in the United States.
In addition, a number of preliminary studies have found
that lutein is available in both breast milk and the
umbilical cord plasma. This suggests that mothers transfer
lutein to their fetuses and newborns, providing them
with this beneficial antioxidant. Future studies should
continue investigating the potential beneficial role
of lutein and maternal nutrition.
The December 2004 JACN Supplement contains proceedings
from the First International Scientific Symposium on
Eggs and Human Health: Transition from Restrictions
to Recommendations, sponsored by the Egg Nutrition Center.
Source:www.seniorjournal.com
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