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Asthma and Obesity
The Nurses Health Study II, a
prospective study of 116,678 female nurses found that the more overweight a nurse was, the
greater her risk of developing asthma in adulthood.
Dr. Carmago and associates tracked the
89,061 who did not have asthma in 1991 and found that 1,652 developed asthma between 1991
and 1995.
Those
who were most obese in 1991 were three times as likely to develop asthma as those who were
the least overweight.
The researchers reported that this
large, prospective cohort study demonstrated that high BMI and weight gain since age 18
are associated with increased risk of developing adult-onset asthma.
"These data add to existing
evidence that excess body fat is a major cause of human disease and suggest a new avenue
for asthma management and prevention.... The increasing prevalence of obesity in developed
nations may help explain concomitant increases in asthma prevalence."138
In an accompanying editorial, concerns
were raised about the study's methods, interpretation of statistical
"associations," and the possible existence of unrecognized cofactor(s).
"If future studies support a
convincing and real association between asthma and obesity, our speculation is that it
will most likely be via an indirect mechanism or through the presence of some cofactor,"
wrote editorialist Mark M. Wilson, MD.139
In a second study, it was
observed that the most overweight 26-year-olds were
80% likely to have asthma than the thinnest.
A Connection Between Immunity and
Obesity
The connection between overweight and
depressed immune systems was made in the mid-eighties, when a vital clue to immunity was
uncovered by brilliant research in an unexpected discipline - biochemistry.
Biochemists established that all cell
replication in the immune system, and therefore all immune strength, is dependent on the
availability of the amino acid glutamine.
Although the immune system utilizes
huge amounts of glutamine, immune cells cannot make it. Only muscle cells are capable of
producing glutamine.
So, your muscles have to supply large
amounts of glutamine to your immune system every day in order to maintain it.
Therefore, muscle loss results in a
corresponding loss of immunity.
Between the ages of 20 and 40 the average American woman loses 8
lbs of muscle and gains 23 pounds of fat.
By 40 her immunity is seriously
compromised.
Although the only long-term solution
to proper muscle maintenance is weight-bearing exercise, glutamine can be increased
through the addition of the branched chain amino acids, leucine, isoleucine and valine.
Best is ornithine-alpha-ketoglutarate (OKG), which provides the glutamine in a stable form
without ammonia.
Ketoisocaproate (KIC), the ammonia
free form of leucine and OKG is considered to be among the best of the glutamine
precursors.
A study of 914 patients with asthma
reported that women with asthma had more daytime and nighttime symptoms than men, along
with worse quality of life, even though airflow obstruction was essentially the same in
both sexes.
The investigators found that women in the 35-55-year-old age bracket
uniformly reported worse physical functioning on a quality of life scale, poorer social
functioning and more bodily pain than men. The women also consumed more health care
resources.140,141
Does the reduction of
body fat reduce the symptoms of asthma? That is one of the questions the RAINS Study hopes
to eventually answer.
Nutritional Deficiency and BMI
A study of the incidence and clinical significance of nutritional
deficiencies in patients with emphysema undergoing lung volume reduction surgery (LVRS)
reported that while a preoperative analysis of the serum nutritional indexes revealed no
clinically significant differences between two groups (BMI was normal in 24 patients (47%), and 27 patients
(53%) had a below normal BMI), postoperative
levels were significantly lower in the low BMI group.Clinically, 26% of the patients in
the low BMI group required prolonged ventilatory support, compared to only 4% of the
patients with a normal BMI.
The hospital length of stay (LOS) also differed, averaging 15.9 days
in the low BMI group, compared to an average of 11.8 days in the normal BMI group. The
researchers concluded that approximately 50% of patients undergoing LVRS for emphysema
have a deficient nutritional status identifiable by BMI, but not by standard nutritional
indexes.
This impaired nutritional status is associated with increased
morbidity following LVRS.
They suggest that BMI is an accurate determinant of nutritional
status in this patient population, and speculate that preoperative repletion of nutritional deficiencies
may decrease hospital morbidity, hospital LOS, and overall costs in the malnourished
population undergoing LVRS.142
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