Is intake of breakfast cereals related to total and cause-specific
mortality in men?1–3
Simin Liu, Howard D Sesso, JoAnn E Manson, Walter C Willett, and Julie E Buring
KEY WORDS
Whole-grain cereals, refined-grain cereals,
prospective study, cardiovascular diseases, mortality, men, Physicians’
Health Study
INTRODUCTION
Dietary guidelines have long recommended consumption of
grain products to maintain health and prevent chronic diseases
(1, 2). However, most grain products consumed in the US are
highly refined (3), which often leads to the loss of many potentially
beneficial micronutrients, antioxidants, minerals, phytochemi594
cals, and fiber (4–6). Large prospective studies found that
increased intakes of whole-grain products are associated with
reduced risks of type 2 diabetes (7, 8), hypertension (6, 9), and
cardiovascular disease (CVD) (10–12). Two other prospective
studies indicated increased risks of type 2 diabetes and total mortality associated with the intake of refined-grain products (8, 13,
14). Taken together, the results of these studies raise important
questions regarding the net effect of increasing total grain intake
on chronic disease risk. Although breakfast cereals are a major
source of both whole and refined grains, their total effect on total
and CVD-specific mortality remains to be clarified (6), especially
in men. To provide further data on the relative importance of
types or amounts of grain, we examined associations between the
intakes of whole-grain and refined-grain breakfast cereals and the
risks of total and CVD-specific mortality in a large prospective
cohort of US male physicians.
SUBJECTS AND METHODS
Study design
The Physicians’ Health Study was a randomized, double-blind,
placebo-controlled trial testing the efficacy of aspirin and
-carotene in the primary prevention of CVD and cancer. The
study’s methodology was described previously (12, 13). In brief,
potentially eligible participants were male physicians who resided
in the United States in 1982. Letters of invitation, informed consent forms, and baseline questionnaires were mailed to the 261 248
men listed on an American Medical Association mailing tape. By
31 December 1983, 104 353 physicians had responded to the initial enrollment questionnaire. Men with a history of cancer and
1
From the Division of Preventive Medicine (SL, HDS, JAEM, and JEB) and
Channing Laboratory (JAEM and WCW), Department of Medicine, Brigham
and Women’s Hospital and Harvard Medical School, Boston; the Department
of Ambulatory Care and Prevention, Harvard Medical School, Boston (JEB);
and the Departments of Epidemiology (SL, HDS, JAEM, WCW, and JEB) and
Nutrition (WCW), Harvard School of Public Health, Boston.
2
Supported by grants HL-42441 and DK02767 from the National Institutes
of Health.
3
Reprints not available. Address correspondence to S Liu, Division of Preventive Medicine, Brigham and Women’s Hospital, 900 Commonwealth
Avenue East, Boston, MA 02215. E-mail: [email protected].
Received June 11, 2002.
Accepted for publication August 7, 2002.
Am J Clin Nutr 2003;77:594–9. Printed in USA. © 2003 American Society for Clinical Nutrition
Downloaded from www.ajcn.org at UCLA Biomedical Lib 12-077 Ctr for Hlth Sci on February 3, 2006
ABSTRACT
Background: Prospective studies suggested that substituting
whole-grain products for refined-grain products lowers the risks of
type 2 diabetes and cardiovascular disease (CVD) in women.
Although breakfast cereals are a major source of whole and
refined grains, little is known about their direct association with
the risk of premature mortality.
Objective: We prospectively evaluated the association between
whole- and refined-grain breakfast cereal intakes and total and
CVD-specific mortality in a cohort of US men.
Design: We examined 86 190 US male physicians aged 40–84 y in
1982 who were free of known CVD and cancer at baseline.
Results: During 5.5 y, we documented 3114 deaths from all
causes, including 1381 due to CVD (488 myocardial infarctions
and 146 strokes). Whole-grain breakfast cereal intake was inversely
associated with total and CVD-specific mortality, independent of
age; body mass index; smoking; alcohol intake; physical activity;
history of diabetes, hypertension, or high cholesterol; and use of
multivitamins. Compared with men who rarely or never consumed
whole-grain cereal, men in the highest category of whole-grain
cereal intake (≥ 1 serving/d) had multivariate-estimated relative
risks of total and CVD-specific mortality of 0.83 (95% CI: 0.73,
0.94; P for trend < 0.001) and 0.80 (0.66, 0.97; P for trend < 0.001),
respectively. In contrast, total and refined-grain breakfast
cereal intakes were not significantly associated with total and
CVD-specific mortality. These findings persisted in analyses
stratified by history of type 2 diabetes, hypertension, and
high cholesterol.
Conclusions: Both total mortality and CVD-specific mortality
were inversely associated with whole-grain but not refined-grain
breakfast cereal intake. These prospective data highlight the
importance of distinguishing whole-grain from refined-grain cereals in the prevention of chronic diseases.
Am J Clin Nutr
2003;77:594–9.
BREAKFAST CEREAL INTAKE AND MORTALITY IN MEN
CVD were excluded, which left a total of 92 785 participants.
After further excluding those who did not provide information on
breakfast cereal intake (7.1%), the final population for analyses
consisted of 86 190 men.
Data collection
Ascertainment of death endpoints
Deaths were identified through systematic searches of the National
Death Index for the entire enrollment cohort, and death certificates
were obtained from state agencies for all deaths that occurred before
1 February 1988. The deaths were classified by trained nosologists
according to the International Classification of Diseases, ninth revision. The “Automated Classification of Medical Entities Decision
Tables” was used to select the underlying cause of deaths that occurred
during a mean follow-up period of 5.5 y. We chose as endpoints all
deaths and deaths caused by CVD. The reliability of the National
Death Index for epidemiologic purposes has been validated (17).
Statistical analysis
We considered intakes of whole-grain, refined-grain, and total
breakfast cereals as both continuous (servings/d) and categorical variables. In initial descriptive analyses, we first examined the distributions of total, whole-grain, and refined-grain breakfast-cereal intakes.
Because the distributions of these variables were not symmetrical
(skewed to the high end) and were somewhat truncated, we did
not use quintiles to categorize intake. Rather, we categorized
cereal intake as rarely or never, 1 serving/wk, 2–6 servings/wk,
and ≥ 1 serving/d to maintain a gradient of exposure and to include
adequate person-years in each category. We then computed means
or proportions of baseline risk factors according to categories of
whole-grain, refined-grain, or total cereal intake. Cox proportional
hazards models were used to estimate age- and multivariateadjusted hazard rate ratios (RRs) for each intake category, as compared with the reference category (rarely or never), for both total
mortality and CVD-specific mortality. The multivariate analyses
were adjusted for age (in years); body mass index; smoking; alcohol intake; physical activity; history of high blood cholesterol,
hypertension, and diabetes; and use of multivitamins. We then
conducted stratified analyses according to baseline risk conditions
including diabetes (yes or no), hypertension (yes or no), and high
cholesterol (yes or no). Tests for a linear trend across increasing
categories of breakfast cereal intake were conducted by treating
the median intake (servings/d) in each category as a continuous
variable. All analyses were conducted with SAS (version 8; SAS
Institute Inc, Cary, NC). All P values were two-sided.
RESULTS
At baseline in 1982, 19% of men reported consuming, on
average, ≥ 1 serving of breakfast cereal/d and 12% reported consuming ≥ 1 serving of whole-grain breakfast cereal/d. Men who
had a greater intake of cereal products (regardless of type) were
older, more physically active, and had a lower prevalence of heavy
smoking or overweight. Use of multivitamin supplements and history of diabetes, hypertension, or high cholesterol did not vary
appreciably across categories of breakfast cereal intake (Table 1).
During an average of 5.5 y (range: 1–6.6 y) of follow-up, we identified 3114 deaths from all causes, including 1381 due to CVD (488
due to myocardial infarctions and 146 due to strokes). There was a
graded inverse relation of intake of whole-grain breakfast cereals to
total mortality (Table 2). Relative to the men in the lowest category of
whole-grain breakfast cereal intake (rarely), the age-adjusted RR of
total mortality for men in the highest category (≥ 1 serving/d) was 0.73
(95% CI: 0.65, 0.82; P for trend = 0.0001). Higher intakes of wholegrain breakfast cereals were also associated with lower risks of mortality from CVD (age-adjusted RR: 0.72; 95% CI: 0.61, 0.85; P for
trend < 0.001) or myocardial infarctions (RR: 0.77; 95% CI: 0.57, 1.01;
P for trend = 0.01) (Table 3). In multivariate models that also adjusted
for cigarette smoking; alcohol intake; physical activity; body mass
index; history of diabetes, high cholesterol, and hypertension; and use
of multivitamins, these associations remained significant. When comparing the highest category of whole-grain breakfast-cereal intake to
the lowest category, the multivariate RRs were 0.83 (95% CI: 0.73,
0.94; P for trend < 0.001) for total mortality, 0.80 (95% CI: 0.66, 0.97;
P for trend = 0.008) for CVD mortality, and 0.71 (95% CI: 0.51, 0.98;
P for trend = 0.01) for myocardial infarction mortality. In contrast,
intakes of total and refined-grain breakfast cereals were not significantly
associated with total and CVD-specific mortality (Tables 2 and 3).
We further examined the associations between the intake of
breakfast cereals and mortality risk in the men who did not have
a history of diabetes, high cholesterol, or hypertension at baseline.
In these subgroup analyses in which participants with a history of
diabetes, high cholesterol, or hypertension were further excluded,
whole-grain cereal intake remained inversely associated with total
and CVD-specific mortality, whereas total or refined-grain cereal
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On the baseline questionnaire, physicians self-reported CVD
risk factors, including age; cigarette smoking status [never, past,
current (including number of cigarettes smoked daily)]; alcohol
intake (rarely or never, monthly, weekly, daily); use of multivitamin supplements; history of hypertension, high cholesterol, and
diabetes; and frequency of vigorous exercise (rarely, 1 time/wk,
2–4 times/wk, ≥ 5 times/wk). Body mass index (in kg/m2) was calculated by using reported height and weight.
Study participants also completed an abbreviated, simple semiquantitative food-frequency questionnaire (SFFQ). On these dietary
questionnaires, men reported their average intake of breakfast cereals
of a specific portion size during the past year, including the amounts,
brands, and types of cereals consumed and the frequency of their consumption. These items were selected from a validated SFFQ used in
the Nurses’Health Study in 1980 to discriminate and rank dietary intake
among participants (15). A full description of the SFFQs and data on
reproducibility and validity in the Nurses’Health Study was previously
reported (15). The ability of the Nurses’ Health Study SFFQ to assess
the intake of individual grain products was documented to be good (16).
For example, in a sample of the participants, correlation coefficients
between the SFFQ and detailed diet records were 0.75 for cold breakfast cereal. Overall, these data indicate that the SFFQ provides reasonably valid measures of long-term average dietary intakes. For each food
item on the questionnaire, 7 responses regarding frequency of intake
were possible, ranging from never to ≥ 2 servings/d. We used a procedure developed by Jacobs and colleagues to classify breakfast cereals
into whole and refined grains (7). Specifically, the breakfast cereals
listed in the SFFQ were evaluated for whole-grain and bran content;
breakfast cereals that contained ≥ 25% whole grain or bran by weight
were classified as whole grain, which is the classification used by Jacobs
et al and others (10, 11). To maintain a high specificity in the definition
of whole-grain cereals, we included responses in which brand names
were missing in the category of refined grains, because refined-grain
cereals were more readily available in the market in the 1980s than were
whole-grain cereals (3). Sensitivity analyses in which this assumption
was varied did not materially change our findings (data not shown).
595
596
LIU ET AL
TABLE 1
Baseline characteristics according to intakes of whole-grain, refined-grain, and total breakfast cereals in the Physicians’ Health Study enrollment cohort1
Whole-grain cereals
Rarely
≥ 1 serving/d
(n = 58 202)
(n = 10 004)
Characteristic
Total breakfast cereals
Rarely
≥ 1 serving/d
(n = 30 425)
(n = 16 305)
55 ± 92
25.0 ± 3
44
57 ± 9
24.4 ± 3
36
54 ± 9
25.0 ± 3
44
58 ± 10
24.4 ± 3
35
54 ± 9
25.1 ± 3
46
57 ± 10
24.4 ± 3
35
32
18
34
15
24
15
38
22
30
17
35
17
28
16
35
20
36
18
31
14
26
16
37
21
44
41
4
9
53
41
3
3
46
41
4
9
49
42
3
5
41
42
5
12
52
41
3
4
17
12
45
26
19
3
18
7
19
11
43
26
18
3
18
7
17
11
45
26
26
3
18
7
20
12
39
28
27
4
19
7
17
11
43
29
24
3
19
7
19
11
41
27
29
4
18
7
1
Because of the large number of subjects, P values for trend for all the variables except history of high cholesterol were < 0.05. Percentage values in
some columns may not add up to 100% because of rounding or missing data.
2–
x ± SD.
3
Assessed by asking, How often do you exercise vigorously enough to work up a sweat?
intake remained unrelated to mortality (Figure 1). For example,
when the highest and lowest categories of whole-grain cereal
intake were compared, the multivariate RRs among participants
without a history of diabetes were 0.76 (95% CI: 0.65, 0.90; P for
trend = 0.0001) for total mortality and 0.73 (95% CI: 0.55, 0.96;
P for trend = 0.004) for CVD-specific mortality. When the highest and lowest categories of refined-grain cereal intake were compared, the multivariate RRs among participants with a history of
diabetes were 1.39 (95% CI: 0.97, 1.98; P for trend = 0.07) for
total mortality and 1.47 (95% CI: 0.96, 2.24; P for trend = 0.08)
for CVD-specific mortality.
DISCUSSION
In this large prospective study of US male physicians who were
followed for 5.5 y, we found a modest, graded association between
TABLE 2
Adjusted hazard rate ratios and 95% CIs of total mortality by cereal intake in the Physicians’ Health Study enrollment cohort1
Intake
Whole-grain breakfast cereals
Total no. of participants
No. of cases
Model 1
Model 2
Refined-grain breakfast cereals
Total no. of participants
No. of cases
Model 1
Model 2
Total breakfast cereals
Total no. of participants
No. of cases
Model 1
Model 2
2–6 servings/wk
≥ 1 serving/d
Rarely
1 serving/wk
P for trend
58 202
2228
1.00
1.00
7219
219
0.85 (0.74, 0.98)
0.88 (0.76, 1.01)
10 765
321
0.78 (0.70, 0.88)
0.85 (0.74, 0.97)
10 004
346
0.73 (0.65, 0.82)
0.83 (0.73, 0.94)
58 413
2015
1.00
1.00
12 780
443
1.10 (0.99, 1.21)
1.15 (1.02, 1.29)
8696
327
0.94 (0.84, 1.06)
1.08 (0.95, 1.24)
6301
329
1.03 (0.91, 1.16)
1.09 (0.95, 1.25)
0.92
0.07
30 425
1129
1.00
1.00
19 999
662
0.89 (0.81, 0.98)
1.02 (0.92, 1.14)
19 461
648
0.77 (0.70, 0.84)
0.94 (0.84, 1.05)
16 305
675
0.77 (0.70, 0.84)
0.92 (0.82, 1.02)
< 0.001
0.07
< 0.001
< 0.001
1
Model 1 was adjusted for age. Model 2 was adjusted for age; cigarette smoking; alcohol intake; physical activity; BMI; history of type 2 diabetes, high
cholesterol, and hypertension; and use of multivitamins.
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Age (y)
BMI (kg/m2)
≥ 25 (%)
Physical activity (%)3
< 1 time/wk
1 time/wk
2–4 times/wk
≤ 5 times/wk
Cigarette smoking (%)
Never
Past
Current, < 20/d
Current, ≥ 20/d
Alcohol consumption (%)
Rarely
Monthly
Weekly
Daily
Current use of multivitamin supplement (%)
History of diabetes (%)
History of hypertension (%)
History of high cholesterol (%)
Refined-grain cereals
Rarely
≥ 1 serving/d
(n = 58 413)
(n = 6301)
BREAKFAST CEREAL INTAKE AND MORTALITY IN MEN
597
TABLE 3
Adjusted hazard rate ratios and 95% CIs of cardiovascular disease (CVD)–specific mortality by cereal intake in the Physicians’ Health Study enrollment cohort1
Intake
1 serving/wk
2–6 servings/wk
≥ 1 serving/d
P for trend
987
1.00
1.00
99
0.89 (0.72, 1.09)
0.93 (0.75, 1.17)
140
0.78 (0.65, 0.93)
0.82 (0.68, 0.98)
155
0.72 (0.61, 0.85)
0.80 (0.66, 0.97)
0.0001
0.008
350
1.00
1.00
33
0.83 (0.58, 1.19)
0.83 (0.56, 1.23)
47
0.73 (0.54, 1.00)
0.79 (0.56, 1.10)
58
0.77 (0.57, 1.01)
0.71 (0.51, 0.98)
0.01
0.01
94
1.00
1.00
9
0.88 (0.44, 1.74)
0.92 (0.42, 1.99)
21
1.24 (0.77, 1.99)
1.68 (1.00, 2.80)
22
1.04 (0.65, 1.65)
1.41 (0.85, 2.34)
0.64
0.18
885
1.00
1.00
202
1.14 (0.98, 1.33)
1.18 (0.99, 1.40)
142
0.90 (0.76, 1.08)
1.08 (0.89, 1.31)
152
1.01 (0.85, 1.21)
1.04 (0.84, 1.27)
0.86
0.37
321
1.00
1.00
67
1.04 (0.80, 1.36)
1.08 (0.81, 1.44)
51
0.90 (0.67, 1.21)
1.05 (0.76, 1.44)
48
0.92 (0.68, 1.24)
0.96 (0.68, 1.36)
0.46
0.97
101
1.00
1.00
14
0.70 (0.40, 1.22)
0.79 (0.43, 1.45)
11
0.58 (0.31, 1.09)
0.79 (0.42, 1.49)
20
1.05 (0.65, 1.71)
1.22 (0.71, 2.11)
0.46
0.87
491
1.00
1.00
301
0.92 (0.80, 1.07)
1.04 (0.89, 1.22)
282
0.75 (0.64, 0.86)
0.93 (0.79, 1.10)
307
0.75 (0.65, 0.87)
0.87 (0.74, 1.03)
< 0.001
0.08
183
1.00
1.00
100
0.82 (0.65, 1.05)
0.87 (0.67, 1.14)
98
0.70 (0.55, 0.90)
0.84 (0.62, 1.07)
105
0.72 (0.56, 0.91)
0.76 (0.54, 0.94)
0.002
0.14
49
1.00
1.00
23
0.70 (0.43, 1.15)
0.98 (0.56, 1.74)
32
0.81 (0.52, 1.27)
1.40 (0.84, 2.32)
42
0.94 (0.62, 1.43)
1.54 (0.94, 2.52)
0.36
0.20
1
MI, myocardial infarction. Model 1 was adjusted for age. Model 2 was adjusted for age; cigarette smoking; alcohol intake; physical activity; BMI; history of type 2 diabetes, high cholesterol, and hypertension; and use of multivitamins.
higher intakes of whole-grain breakfast cereals and lower risks of
total and CVD-specific mortality that was independent of known
CVD risk factors. In contrast, intake of refined-grain cereals was
not associated with total and CVD-specific mortality.
Several large prospective studies that examined the relation
between whole-grain intake and the risk of chronic disease found
that increased intakes of whole-grain products are associated with
reduced risks of type 2 diabetes (7, 8), hypertension (6, 9), and
CVD (10–12). Our findings are generally consistent with the
results of these previous prospective studies and extend those
results with an assessment of the relation between types of cereal
grains and total and CVD-specific mortality in men. The magnitude of the association between whole-grain intake and mortality,
with the exception of stroke mortality, is in general agreement
with that of the study by Jacobs et al (14), which was conducted
in a large cohort of women. Whereas neither total nor refinedgrain cereal intake appeared to be significantly related to total and
CVD-specific mortality in the entire cohort of male physicians,
we found a positive, albeit not significant, association between the
intake of refined-grain cereals and CVD-specific mortality among
those participants who had a history of diabetes. Although these
findings in subgroup analysis should be interpreted cautiously,
they nevertheless suggest that a higher intake of refined-grain
cereal products may have harmful effects on CVD endpoints
among individuals with glucose intolerance, a suggestion that
needs to be confirmed by future studies.
Several potential limitations are worthy of discussion. First, the
observed inverse association between whole-grain breakfast cereal
intake and total mortality could be due to confounding by other
heart-healthy lifestyle factors (eg, smoked less, exercised more,
and had lower body mass index) and dietary factors associated
with higher whole-grain intake. However, the apparent protective
association with whole-grain cereal intake persisted in multivariate models accounting for known coronary risk factors. Also, the
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Whole-grain breakfast cereals
CVD mortality
No. of cases
Model 1
Model 2
MI mortality
No. of cases
Model 1
Model 2
Stroke Mortality
No. of cases
Model 1
Model 2
Refined-grain breakfast cereals
CVD mortality
No. of cases
Model 1
Model 2
MI mortality
No. of cases
Model 1
Model 2
Stroke mortality
No. of cases
Model 1
Model 2
Total breakfast cereals
CVD mortality
No. of cases
Model 1
Model 2
MI mortality
No. of cases
Model 1
Model 2
Stroke mortality
No. of cases
Model 1
Model 2
Rarely
598
LIU ET AL
homogeneity in education and occupation of our study population of male physicians should also have minimized confounding by socioeconomic variables that may have affected the
opportunity for screening and treatments. As discussed in Subjects and Methods, the SFFQ used in this study was an abbreviated one that did not provide a comprehensive assessment of the
participants’ usual diet; thus, we could not adjust for other
dietary intakes. However, previous dietary studies did not identify any dietary factors that may confound the association
between grain intake and total mortality in multivariate analyses
in which multiple dietary variables are included in the same
model (14). Vegetables and liver or meat are the only other food
groups that were assessed in the SFFQ. Even after further adjustment for intakes of vegetables and liver, the RRs for the comparison between the highest and lowest categories of wholegrain intake were 0.82 (95% CI: 0.73, 0.94) for total mortality
and 0.79 (95% CI: 0.65, 0.96) for CVD-specific mortality.
Second, some high-risk conditions such as hypercholesterolemia, diabetes, and hypertension may lead to changes in
dietary habits and therefore confound the association between the
intake of whole-grain breakfast cereals and total mortality. However, any biases from these conditions would tend to attenuate the
protective effect of whole-grain cereal intake because the tendency
would be for men to increase their intake of whole grains if they
perceived themselves to have an increased risk of CVD. Moreover,
the inverse association persisted when men with these conditions
at baseline in 1982 were excluded from the main analysis. Finally,
we observed a specific relation of lower total and CVD-specific
mortality with greater intakes of whole-grain cereals but not with
greater intakes of either total or refined-grain cereals even though
greater intakes of total or refined-grain cereals were also related
to heart-healthy lifestyle factors in this study. The specificity of
the whole-grain and mortality relation argues against confounding as a full explanation for our findings.
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FIGURE 1. Multivariate-adjusted hazard rate ratios (RRs) of total
mortality by category of intake of whole-grain ( ) and refined-grain ()
breakfast cereals in 65 390 participants in the Physicians’ Health Study
enrollment cohort who did not have a history of diabetes, hypertension,
or high cholesterol at baseline. For whole-grain and refined-grain cereals, P for trend = 0.0001 and 0.31.
As in any observational study of diet and disease, one major
concern is the measurement error inherent in dietary assessment.
Our SFFQ only assessed a limited number of foods, which hampered our ability to adjust for total energy intake and other dietary
factors that may be important in affecting mortality. In addition,
the definition of whole grain has always been contentious, and
some of the difficulties were pointed out by Jenkins et al (18). In
contrast with intact grain products or stone-ground flour, most
“whole grains” products are reconstituted after milling from the
3 original components: the starchy endosperm, the wheat bran
milled to a specific particle size, and the wheat germ. To prevent
rancidity of the polyunsaturated fats and to lower the fat content
of the products, wheat germs are often heat-treated and, in some
instances, may not be added back in the production process (19).
The final whole-grain products, however, remain high in dietary
fiber. For this reason, we and others (12, 14) have consistently
defined whole grains as those products that contain ≥ 25% whole
grain or bran by weight. In dealing with the issue of misclassification, our approach was to compare findings from sensitivity
analyses that either keep bran in or leave it out of the classification system. Results from these sensitivity analyses were similar.
Furthermore, the SFFQ was designed to rank and contrast longterm average cereal intakes among participants rather than to
assess absolute intakes. Thus, total cereal intakes may have been
underestimated. In a prospective setting, however, such an underestimation of intake would be unlikely to differ by survival status
and would thus tend to cause an underestimation of the dietdisease relation rather than a spurious relation. Therefore, the
20% lower total mortality observed with greater intakes of
whole-grain cereals may be a conservative estimate.
Although the exact mechanisms responsible for the benefits of whole
grains remain to be elucidated, multiple mechanistic pathways, including reduction in lipids and blood pressure and improvement of insulin
sensitivity and glucose tolerance, have been suggested. Much attention
has focused on individual components of whole grains, such as dietary
antioxidants, minerals, enzyme inhibitors, dietary fiber, folate, and B
vitamins, which may independently or jointly contribute to the lower
mortality associated with greater intakes of whole grains (6, 12, 20–22).
Identifying a direct relation between the intake of specific types
of cereal and mortality can provide a scientific rationale for formulating dietary guidelines. Until recently, however, the prevailing health advice has been to increase the intake of total grains
rather than of specific types of grains to prevent chronic diseases,
a recommendation primarily intended to lower the intake of saturated fat and cholesterol. Several developments have drawn attention to the importance of whole grains. One of the goals in Healthy
People 2010 is to “increase the proportion of persons aged 2 y and
older who consume at least 6 daily servings of grain products,
with at least 3 being whole grains” (goal 19-7; 2). The 2000
Dietary Guidelines for Americans makes the following recommendation: “Choose a variety of grains daily, especially whole
grains. . . eating plenty of whole grains. . . as part of the healthful
eating patterns. . . may help protect you against many chronic diseases” (1). Nevertheless, these guidelines still implicitly advocate
the intake of a large amount of refined grains, even though large
prospective studies have consistently shown no benefit or harmful
effects of refined-grain products. Of significant concern is the fact
that most grain products consumed in the United States are highly
refined (3). Although data directly comparing the effects of
refined-grain products to those of saturated fats on CVD mortality are sparse, our data indicate that whole-grain products should
BREAKFAST CEREAL INTAKE AND MORTALITY IN MEN
SL participated in the study design, data collection, data analysis, and the
writing of the first draft of the manuscript. HDS, WCW, JEB, and JAEM participated in the study design and data collection. All authors participated in the
writing of the manuscript. None of the authors had any financial conflict of
interest. In 2001 SL received honoraria from General Mills Co for a presentation unrelated to this article.
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be a good substitute either for products with a high saturated fat
content or for refined-grain cereals. Compared with whole-grain
products, refined-grain products often contain lower amounts of
many potentially beneficial micronutrients, antioxidants, minerals, phytochemicals, and fiber. In our cohort, the men in the highest category of whole-grain breakfast-cereal intake (only 12%
of total participants) consumed ≥ 1 serving of whole-grain breakfast cereals/d and had an 20% lower risk of total mortality than
did the men in the lowest category, who rarely or never consumed
whole-grain breakfast cereals. Thus, substituting high-fiber products (ie, whole-grain cereals, fruit, and vegetables) for low-fiber
refined-grain products may have a significant effect on public
health (22–26).
In conclusion, in this large population of men, both total mortality and CVD-specific mortality were inversely associated with
intakes of whole-grain breakfast cereals but not with intakes of
refined-grain breakfast cereals. These prospective data highlight
the importance of distinguishing whole-grain cereal products from
refined-grain ones for the prevention of premature death.
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