Large scale human studies repeatedly confirm benefits
of apples and apple phytochemicals in improvement of asthma, lung function and
overall lung health.
The clearest effectwas seen in individuals with
the highest consumption of apples.
Researchers consistently express high confidence that
apples and apple polyphenols improve lung function in humans with asthma.
Apple consumption
has been inversely linked with asthma and has also been positively
associated with general pulmonary health. In a recent study involving
1600 adults in Australia, apple and pear intake was associated with a
decreased risk of asthma and
a decrease in bronchial
hypersensitivity, but total fruit and vegetable intake was not
associated with asthma risk or severity. Specific antioxidants, such as
vitamin E, vitamin C, retinol, and β-carotene,
were not associated with asthma or bronchial hypersensitivity. Previously it
had been found that apple intake,
as well as selenium intake, was
associated with less asthma in adults in the United Kingdom. This
study surveyed nearly 600 individuals with asthma and 900 individuals
without asthma about their diet and lifestyle. Total fruit and vegetable
intake was weakly associated with asthma, and
apple intake showed a stronger
inverse relationship with asthma. This latter effect was most clear in
subjects who consumed at least two apples per week. Onion, tea, and
red wine consumption were not related to asthma incidence, suggesting
an especially beneficial effect of
apple flavonoids. Vitamin C and vitamin E were not correlated with
asthma incidence, and carotene intake was weakly, but positively, associated
with asthma. Apple intake and
orange intake were both associated
with a reduced incidence of asthma in the Finnish study involving 10,
000 men and women. Flavonoid intake
in general was associated with a lower risk of asthma, and the
association was attributed mainly to quercetin, hesperitin, and naringenin. Other fruits and vegetables,
such as onions, grapefruit, white cabbage, and juices, were not associated
with a decreased risk in asthma.
In a study of over 13,000 adults in the Netherlands, it was
found that apples might beneficially
affect lung function.
Apple
and pear intake was positively
associated with pulmonary function and negatively associated with chronic
obstructive pulmonary disease. Catechin intake was also associated
with pulmonary function and negatively associated with chronic obstructive
pulmonary disease, but there was no association between tea, the main source
of catechins, and chronic obstructive pulmonary disease. A study of
approximately 2500 middle aged (45–59 yrs) Welsh men also demonstrated a
beneficial effect of apple
consumption on lung function. Lung function was measured as forced
expiratory volume (FEV) in one second, and was positively correlated with
citrus fruit, fruit juice/squash, and
apple consumption. However,
the association with citrus fruit and fruit juice/squash lost significance
after adjustment for smoking. Apple consumption remained positively
correlated with lung function after taking into account possible confounders
such as smoking, body mass index, social class, and exercise. Participants
who consumed five or more apples per week had a significantly greater FEV of
138 mL when compared to those who did not consume apples.
American Journal
of Clinical Nutrition, Vol. 76, No. 3, 560-568, September 2002
Background:Flavonoids are effective
antioxidants and may protectagainst several chronic diseases.
Objective:
The association between flavonoid intake and riskof several
chronic diseases was studied.
Design: The total dietary intakes of 10 054 men and women duringthe year preceding the baseline examination were determined
with a dietary history method. Flavonoid intakes were estimated,
mainly on the basis of the flavonoid concentrations in Finnish
foods. The incident cases of the diseases considered were identifiedfrom different national public health registers.
Results:
Persons with higher quercetin intakes had lower mortalityfrom
ischemic heart disease. The relative risk (RR) betweenthe
highest and lowest quartiles was 0.79 (95% CI: 0.63, 0.99:P
for trend = 0.02). The incidence of cerebrovascular diseasewas
lower at higher kaempferol (0.70; 0.56, 0.86; P = 0.003),
naringenin (0.79; 0.64, 0.98; P = 0.06), and hesperetin (0.80;0.64, 0.99; P = 0.008) intakes. Men with higher
quercetin
intakeshad a lower lung cancer incidence (0.42; 0.25, 0.72; P
= 0.001),and men with higher myricetin intakes had a lower
prostate cancerrisk (0.43; 0.22, 0.86; P = 0.002).
Asthma
incidence was lowerat higher quercetin (0.76; 0.56, 1.01; P
= 0.005), naringenin(0.69; 0.50, 0.94; P = 0.06), and
hesperetin (0.64; 0.46, 0.88;P = 0.03) intakes. A trend toward a reduction in risk
of type2 diabetes was associated with higher quercetin
(0.81; 0.64,1.02; P = 0.07) and myricetin (0.79; 0.62,
1.00; P = 0.07) intakes.
Conclusion:
The risk of some chronic diseases may be lower athigher dietary
flavonoid intakes.
Excerpts:
"The incidence of asthma was lower at higher total flavonoid intakes
(RR: 065; 95% CI: 0.47, 0.90; P = 0.04).
This association was due to
quercetin(0.76; 0.56, 1.01; P = 0.05), hesperetin (0.64;
0.46, 0.88; P = 0.03), and naringenin (0.69; 0.50, 0.94; P =
0.06)."
"The
strongest associations were noted for apple (0.55; 0.40, 0.76; P
= 0.001) and orange (0.71; 0.52, 0.98; P = 0.09) intakes."
"Of the main flavonoid sources, apple intake was associated with almost all of the chronic diseases
considered. Apple intake was, after adjustment for intake of
vegetables and fruit other than apples,
inversely associated with
occurrence of all cancers combined,
lung cancer, asthma, type 2 diabetes, thrombotic stroke, total
mortality and ischemic heart disease mortality."
Am J
Respir Crit Care Med. 2001 Nov 15;164(10 Pt 1):1823-8.
Dietary antioxidants and asthma in adults:
population-based case-control study.
Department of Public Health Sciences, King's College, Capital House, London,
United Kingdom. seif.shaheen@kcl.ac.uk
A protective role for dietary antioxidants in asthma has been proposed.
However, epidemiological evidence to implicate antioxidant vitamins is weak,
and data on the role of flavonoid-rich foods and antioxidant trace elements
are lacking. We carried out a population-based case-control study in South
London, UK, to investigate whether asthma is less common and less severe in
adults who consume more dietary antioxidants. Participants were aged 16-50
yr and registered with 40 general practices. Asthma was defined by positive
responses to a standard screening questionnaire in 1996, and complete
information about usual diet was obtained by food frequency questionnaire
from 607 cases and 864 controls in 1997. After controlling for potential
confounding factors and total energy intake,
apple consumption was
negatively associated with asthma (odds ratio [OR] per increase in frequency
group 0.89 [95% confidence interval [CI]: 0.82 to 0.97]; p = 0.006). Intake
of selenium was also negatively associated with asthma (OR per quintile
increase 0.84 [0.75 to 0.94]; p = 0.002). Red wine intake was negatively
associated with asthma severity. The associations between
apple and red wine
consumption and asthma may indicate a protective effect of flavonoids. The
findings for dietary selenium could have implications for health policy in
Britain where intake has been declining.
Excerpts: "The
clearest effectwas seen in individuals who ate apples twice a
week or more."
"Intakes
of other fruits(citrus, pears, bananas) were not related to
asthma after controllingfor intake of apples and
selenium."
"In this population-based study,
we have found that asthma was less
common in adults who consumed more apples and who had ahigher
intake of selenium."
PMID: 11734430 [PubMed - indexed for MEDLINE]
Thorax 2000;55:102-108
( February )
Diet, lung function, and lung function
decline in a cohort of 2512 middle aged men
Barbara K Butlanda, Ann M Fehilyb,
Peter C Elwoodc
a Department
of Public Health Sciences, St George's Hospital Medical School, Cranmer
Terrace, London SW17 0RE, UK, b H J Heinz
Company Ltd, Kitt Green, Wigan, Lancashire WN5 0JL, UK, c MRC
Epidemiology Unit (South Wales), Llandough Hospital, Penarth, South
Glamorgan CF64 2XW, UK
Correspondence to: Ms B K Butland
Received 2 June 1999; Returned to authors 4 August 1999;
Revised version received 22 October 1999; Accepted for publication 5
November 1999
BACKGROUNDA
prospective cohort study of 2512 Welshmen aged 45-59 living in Caerphilly in
1979-1983 was used to investigate associationsbetween diet and
lungfunction. METHODSAt
baseline (phase I) and at five year follow up (phase II), forced expiratory
volume in one second (FEV1) was measured usinga
McDermott spirometer and dietary data were obtained using a
semi-quantitative food frequencyquestionnaire. RESULTSGood
lung function, indicated by high maximum FEV1 given age
and height, was associated with high
intakes of vitamin C, vitaminE,
-carotene,
citrus fruit, apples, and the
frequent consumptionof fruit juices/squashes. Lung function was
inversely associatedwith magnesium intake but there was no
evidence of an associationwith fatty fish.
Following adjustment for confounders
includingbody mass index, smoking history, social class,
exercise, andtotal energy intake,
only the associations with vitamin E
andapples persisted, with lung function estimated to be
39 ml (95%confidence interval (CI) 9 to 69) higher for vitamin E
intakesone standard deviation (SD) apart and 138 ml higher (95%
CI 58to 218) for those
eating
five or more apples per week comparedwith non-consumers.
Decline in lung function between phases wasnot significantly
associated with the changing intakes of applesor vitamin E. An
association between high average apple consumptionand slow
decline in lung function lost significance after adjustmentforconfounders. CONCLUSIONSA
strong positive association is seen between lung function and the number of
apples eaten per week cross sectionally, consistentwith a
protective effect of hard fruit rather than soft/citrusfruit.
The recent suggestion that such effects are reversiblewas not
supported by our longitudinalanalysis.
We have demonstrated a
positive cross sectional association
between lung function and the number of apples eaten per weekin a cohort of middle aged Welshmen. This association appeared
to be independent of vitamin E and vitamin C intakes and may thereforebe explained by other antioxidant constituents of apples suchas flavonoids (e.g. quercetin).
Am. J. Respir. Crit. Care Med., Volume 164, Number 1, July 2001,
61-64
Chronic Obstructive Pulmonary Disease and Intake of
Catechins, Flavonols, and Flavones
The MORGEN Study
CORA TABAK,
ILJA C. W. ARTS,HENRIETTE A. SMIT,DICK HEEDERIK,and DAAN KROMHOUT
Department of Chronic Disease Epidemiology and Division of
Public Health Research, National Institute of Public Health and the
Environment, Bilthoven; the Institute for Risk Assessment Sciences, Division
Environmental and Occupational Health, University Utrecht, Utrecht; and
Wageningen Research Centre, State Institute for Quality Control of
Agricultural Products (RIKILT), Wageningen, The Netherlands
Flavonoids have
been suggested to protect against chronic lung disease. We studied
intake of catechins, flavonols, and flavonesin relation to
pulmonary function and COPD symptoms in 13,651adults from three
Dutch cities examined from 1994 to 1997. Dietaryintake was
estimated using a food frequency questionnaire, andflavonoid
intake was calculated using specific food compositiontables.
Pulmonary function (FEV1) was determined by spirometry
and COPD symptoms by questionnaire. Associations were presented
for the fifth versus the first quintile of intake (Q5-Q1), adjustedfor age, height (for FEV1 only), sex, smoking, BMI, and
energyintake. Smoking was strongly associated with COPD,
independentof dietary effects. Average catechin, flavonol, and
flavone intakewas 58 mg/d (SD = 46) with tea and apples as main
sources. Totalcatechin, flavonol, and flavone intake was
positively associatedwith FEV1 (Q5-Q1
= 44 ml, 95% CI = 18-69) and inversely associatedwith chronic
cough (ORQ5-Q1 = 0.80, 95% CI = 0.66-0.97) and breathlessness(ORQ5-Q1 = 0.74, 95% CI = 0.58- 0.94), but not chronic
phlegm.Catechin intake was independently associated with FEV1
(Q5-Q1= 130 ml, 95% CI = 101-159) and all three COPD symptoms (ORQ5-Q1= 0.60-0.72, p < 0.001). Flavonol and flavone intake was independentlyassociated with chronic cough only. Solid fruit, but not tea,intake was beneficially associated with COPD. Our results suggesta beneficial effect of a high
intake of catechins and solid fruitsagainstCOPD.
Excerpts: "A
protective effect of flavonoidsagainst chronic lung disease
has been hypothesized by Miedemaand colleagues (5). They
suggested that the stronger associationwith 25-yr incidence of
asthma and COPD observed for solid fruits(apples, pears) than
for other types of fruits, may be
due tothe high level of flavonoids in apples."
Am J Clin Nutr. 2003 Sep;78(3):414-21.
Food and nutrient intakes and asthma risk in young
adults.
Department of Epidemiology & Preventive Medicine, Central and Eastern
Clinical School, Monash University, and The Alfred Hospital, Melbourne,
Victoria, Australia.
BACKGROUND: Some aspects of diet are relatively newly recognized potential
risk factors for asthma, but the evidence to date is conflicting. OBJECTIVE:
The goal was to determine whether the food and nutrient intakes of adults
with asthma differ from those of adults without asthma. DESIGN: This was a
community-based, cross-sectional study of 1601 young adults ( +/- SD age:
34.6 +/- 7.1 y) who were initially recruited by random selection from the
federal electoral rolls in Melbourne in 1999. Subjects completed a detailed
respiratory questionnaire, a validated semiquantitative food-frequency
questionnaire, skin-prick testing, and lung function tests, including a
methacholine challenge test for bronchial hyperreactivity (BHR). A total of
25 nutrients and 47 food groups were analyzed by using multiple logistic
regression with alternate definitions of asthma and atopy as the outcomes.
RESULTS: Whole milk appeared to protect against current asthma (odds ratio:
0.66; 95% CI: 0.46, 0.97), doctor-diagnosed asthma (0.73; 0.54, 0.99), BHR
(0.68; 0.48, 0.92), and atopy (0.71; 0.54, 0.94). Conversely, soy beverage
was associated with an increased risk of current asthma (2.05; 1.19, 3.53),
doctor-diagnosed asthma (1.69; 1.04, 2.77), and BHR (1.65; 1.00, 2.71).
Applesand pears
appeared to protect against current asthma (0.83; 0.71,
0.98), asthma (0.88; 0.78, 1.00),
and BHR (0.88; 0.77, 1.00). CONCLUSIONS:
The consumption of dairy products, soy beverages, and apples and pears, but
not of nutrients per se, was associated with a range of asthma definitions.
Dietary modification after diagnosis is one possible explanation for this
finding. Intervention studies using whole foods are required to ascertain
whether such modifications of food intake could be beneficial in the
prevention or amelioration of asthma.
Excerpt: "...
giventhat the associations between dairy products, soy beverage,and apples and pears
were reasonably consistent across all theoutcome measures,
we are confident that these
represent realunderlying patterns of association."
A
prospective cohort study of 2512 Welshmen aged 45-59 living in Caerphilly in
1979-1983 was used to investigate associations between diet and
lung function.
-carotene,
citrus fruit, 