Philip Morris
Plant Foods and Colon Cancer: An Assessment of Specific Foods and Their Related Nutrients (United States)
Fields
- Author
- Berry, T.D.
- Caan, B.J.
- Coates, A.
- Duncan, D.M.
- Ma, K.N.
- Potter, J.D.
- Slattery, M.L.
- Caan, B.J.
- Type
- PSCI, PUBLICATION SCIENTIFIC
- BIBL, BIBLIOGRAPHY
- Area
- CARCHMAN,RICHARD/OFFICE
- Litigation
- Iwoh/Produced
- Characteristic
- EXTR, EXTRA
- MARG, MARGINALIA
- Site
- R530
- Named Organization
- Univ of Ut
- Ut Cancer Registry
- Mn Cancer Surveillance System
- NC Cancer Registry
- NIH, Natl Inst of Health
- Sacramento Tumor Registry
- Ut Cancer Registry
- Author (Organization)
- Cancer Causes + Control
- Fred Hutchinson Cancer Research Center
- Kaiser Permanente
- Univ of Ut
- Fred Hutchinson Cancer Research Center
- Named Person
- Anderson, K.
- Edwards, S.
- Kerber, R.
- Slattery, M.L.
- Edwards, S.
- Master ID
- 2063633486/4072
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Cancer Causes and Control, 1997, 8, pp. 575-590
Plant foods and colon cancer: an
assessment of specific foods and their
related nutrients (United States)
Martha L. Slattery, John D. Potter, Ashley Coates, Khe-Ni Ma,
T. Dennis Berry, Debra M. Duncan, and Bette J. Caan
(Received 8 October 1996; accepted in revised form 18 December 1996)
Plant foods have been associated inversely with colon cancer. Since a major focus of this study was
to identify
components of plant foods which may account for their association with colon cancer, nutrients which
are commonly
found in plant foods also were evaluated. A population-based case-control study was conducted in
Northern
California, Utah, and the 'Twin Cities' area of Minnesota (United States). Complete data were
available from
interviewer-administered questionnaires on 1,993 cases and 2,410 controls. Higher intakes of
vegetables (for highest
relative to lowest quintile of intake) were associated inversely with colon cancer risle the odds
ratio (OR) was 0.7
for both men (95 percent [CI] confidence interval ~ 0.5-0.9) and women (CI ~ 0.5-1.0). Associations
were stronger
among those with proximal tumors. Total fruit intake was not associated with colon cancer risk
although, among
men, higher levels of whole grain intake were associated with a decreased risk (OR -- 0.6, CI =~
0.4-0.9 for older men);
high intakes of refined grains were associated with an increased risk (OK = 1.5, CI = 1.1-2.1).
Dietary fiber intake
was associated with a decreased risk of colon cancem OR = 0.5 (CI = 0.3-0.9) for older men; OR = 0.7
(CI -- 0.4-1.2)
for older women; OR. = 0.6 (CI -- 0.4-1.0) for men with proximal tumors; OR. = 0.5 (CI = 0.3-0.9)
for women with
proximal tumors. Other nutrients, for which plant foods were the major contributor - such as vitamin
B6, thiamin,
and niacin (women only) - also were associated inversely with colon cancer. Neither p-carotene nor
vitamin C was
protective for colon cancer. Adjustment of plant foods for nutrients found in plant foods or for
supplement use
did not appreciably alter the observed associations between plant foods and colon cancer. Cancer
Causes and Control
1997, 8, 575-590
Key ~vords: [~-carotene, colon cancer, dietary fiber, folate, fruits, thiamin, United States,
vegetables, vitamin C,
vitamin B6, whole grains.
Introduction
Plant foods have been hypothesized to reduce risk of
cancer by the variety of bioactive compounds they
contain, including polyphenolics, allium compounds,
lignans and phytoestrogens, trace minerals, antioxidants,
and dietary fiber.1~ Of the many dietary factors evaluated
for their relationship with colon cancer, vegetables, plant
Dr Slattery, Ms Ma, and Mr Berry are with the Department of Oncological Sciences, University of
Utah, Salt Lake City, Utah, USA.
Dr Potter is with the Fred Hutchinson Cancer Research Center, Seattle, Washington, USA. Drs Coates,
Duncan, and Caan are with
:be Division of Research, Kaiser Permanente Medical Care Program, Oakland, California, USA. Address
correspondence to Dr Slattery,
Department of Oncological Sciences, University of Utah, 546 Chipeta gray, Suite 1100, Salt Lake
City, Utah, USA. This study was
funded by grant ROI CA4899g from the US National Institutes of Health. Case identification and
verification was supported by the
Utah Cancer Registry, the Northern California Cancer Registry, the Sacramento Tumor Registry, and
Cancer Surveillance Program
Region 3 in California, and the Minnesota Cancer Surveillance System.
1997 Rapid Science Publishers
Cancer Causes and Control. Vol 8. 1997 375

I
114.1_ Slattery et al
foods rich in many phytochemicals, nutrients, and fiber
are some of the most consistently identified environ-
mental factors associated with a decreased risk of colon
cancer.~'~ Consumption of fruits and whole grains also
have been associated with decreasing risk of colon cancer,
although the associations are less consistent than those
observed for vegetable intake.('t*
The purpose of this study was to evaluate the associa-
tions between specific plant foods and colon cancer. To
do this, we evaluated specific foods as well as their meas-
urable constituents; analyses were necessarily limited to
nutrients available in standard dietary databases. A major
goal of the study was to determine if measurable
constituents of p/ant foods explained the associations with
colon cancer observed for plant foods. We assessed asso-
ciations in the context of gender-, age-, and site-specific
associations as well as those with and without a family
history of colorectal cancer in order to obtain a better
understanding oĢ subgroups within the population who
may be more or less affected by plant foods and their
contributing nutrients.
Materials and methods
Study population
Study participants were from the Kaiser Permanente
Medical Care Program (KPMCP) of Northern California,
an eight-county area in Utah (Davis, Salt Lake, Utah,
Weber, Wasatch, Toode, Morgan, and Summit Counties)
and the metropolitan 'Twin Cities' (Minneapolis, St. Paul)
area (Anoka, Carver, Dakota, Hennepin, Ramsey; Scott,
and Washington counties) in Minnesota (Unked States).
Eligibility criteria for case subjects included diagnosis
with first primary colon cancer (ICD-O-2" codes 18.0,
18.2-18.9) between 1 October 1991 and 30 September
1994, between 30 and 79 years of age at time of diagnosis,
and mentally competent to complete the interview. Those
with cancer in the rectosigmoid junction or rectum
(defined as the first 15 cm from the anal verge) and those
with known familial adenomatous polyposis, ulcerative
colitis, or Crohn's disease, as indicated on the pathology
report, were not eligible. Abstractors visited each report-
ing hospital or pathology laboratory on a monthly basis
to identify cases. Using this rapid=reporting system, the
majority of case subjects were interviewed within three
months of diagnosis. Of those invited to participate in
the study, 76 percent cooperated, representing 64.5
percent of all eligible cases.
Methods used to ascertah controls have been reported?"
Briefly; control subjects from the K.PMCP were identified
from membership lists; subjects under age 65 from Utah
were identified from random-digit-dialing and lists of
individuals with a current Utah driver's license or state
576 Cancer Causes and Control. Vol 8. 1997
ID; control subjects aged 65 and older in Utah were
identified from Health Care Financing Administration
lists (Social Security); controls subjects in Minnesota were
identified from lists of individuals with a Minnesota driver's
license or state ID. Controls were matched to cases by
five-year age groups and gender. Of all controls asked to
participate, 64 percent cooperated. Reasons for nonpar-
ticipation have been previously outlined.)J The main reason
for nonparticipation by controls was our inability to
locate them (n = 752). Of these, 663 were controls selected
from driver's license lists in Minnesota where new license
holders were added on a regular basis but names of people
who had moved or had died were not removed. Thus, of
all digible controls, a total of 53.2 percent participated in
the interview if unable-to-locate controls from Minnesota
are included in the denominator;, if controls who we are
unable to locate and verify residency were excluded from
the denominator, the total is 63.9 percent.
A total of 2,083 eligible cases and 2,476 digible controls
were interviewed. Of these, 90 cases and 66 controls were
excluded from the analysis because: (i) they were missing
data on a key variable; (ii) data were considered to be of
poor quality by the interviewer;, or (Hi) they reported
Crohn's disease or ulcerative colitis at the time of inter-
view. A tdtal of 1,993 cases and 2,410 controls are included
in the analyses presented. The racial composition of study
participants was: 4.2 percent Black, not Hispanic; 4.4
percent Hispanic; and 91.4 percent White, not Hispanic.
Data were collected by trained and certified interviewers
using laptop computers. After a week of formal training
provided by study staff, interviewers were required to
complete 10 taped interviews which were evaluated for
interviewer behavior, reading of questions, adequate prob-
ing, correct use of the referent year, and ability to obtain
responses from subjects as outlined in the two-volume
interviewer manual developed for the study. The referent
period that study participants were asked to recall was
the year two years prior to the date of diagnosis for
cases or date of selection for controls. The interview
took approximately two hours to complete. Quality con-
trol methods used in the study have been described
elsewhere?4 Briefly, all interviews were audio-taped and
interviews were selected randomly for review for com-
pleteness, consistency, interviewer behavior, probing
behavior, use of the referent period correctly; and other
interviewing behaviors as outlined in the interviewer manual.
Dietary intake
Dietary intake data were ascertained using a ,computerized
adaptation of the CARDIA diet history,ts-t7 This ques-
tionnaire has been compared for relative validity and
reliability of past-month dietary-consumption patterns.
With dais questionnaire, participants were asked to recall
foods eaten, the frequency with which they were eaten,

foods eaten as additions to other foods, and use of fats in
the preparation of foods. Three-dimensional food models
were used to help participants estimate their usual serving
size; cue cards were used to help participants consistently
identify foods within broad categories. Foods eaten away
from home were ascertained and those prepared with fat
were assigned the fat most commonly used at a medium-
priced restaurant. Where it was possible that many types
of food within a category would be eaten, such as types
of cereal, participants were asked to report the three items
mostly commonly eaten. Seasonal consumption was
obtained for fresh and canned fruits, and for four vege-
tables (corn on the cob, tomatoes, summer and winter
squash). Nutrient values for specific foods were calculated
using the Nutrition Coordinating Center (NCC) nutrient
database.'*
Food classification
NCC food codes from the diet history were categorized
into food groups using standard serving sizes. Food codes
for fruits included 15 separate canned, cooked, and frozen
fruits, 23 separate fresh fruits, and eight separate types of
dried fruits. Fruit juice was categorized as orange and
grapefruit juice (two food codes) and other fruit juice
(apple juice or cider, sweetened and low-calorie cranberry
juice, grape juice, grapefruit juice, papaya juice, pineapple
juice, prune juice, and nectars) (these items were later
combined since no difference in association was noted
for these two categories). Standard serving sizes for fruits
were: one-half cup of canned fruit; one piece of most fresh
fruits except for grapefruit (where one-half piece was
considered a standard serving); one-half cup of berries,
cherries, or grapes; one-quarter cup of dried fruit; and six
ounces of fruit juice.
Vegetables were derived from over 55 individual food
items which included: raw and cooked vegetables; salsa;
salads; potatoes which were baked, mashed, or eaten as a
salad; cruciferous vegetables (cabbage, brussels sprouts,
rutabagas, turnips, broccoli, cauliflower, parsnips, oriental
vegetables, and mixed vegetables containing cruciferous
vegetables); onions; legumes; and vegetable juice (two
food codes for mixed vegetable and tomato juice). Vege-
tables prepared with high amounts of fat, such as fried
potatoes, were excluded from these food groupings
because the 'five-a-day' guidelines do not include these
vegetablesJ' Standard serving sizes for vegetables were
one-half of vegetables, except for raw broccoli and
cauliflower where one cup was considered a standard
serving, one-quarter cup of salsa, and six ounces of juice.
Fruits and vegetables, such as apples, apricots, oranges,
grapefruits, tangerines, bananas, berries, tomatoes, salad
greens, and dark yellow vegetables such as carrots and
winter squash also were evaluated using standard serving
sizes to denote level of consumption. These food items
Plant foods and colon cancer
were of interest either because of dietary constituents that
they contain but that were not complete in the nutrient
database, (i.e., lycopene in tomatoes) or because of the
frequency with which they are eaten in the population.
Foods included as part of whole grains included whole
wheat and high fiber breads, bran muffins, whole grain
cereals, brown rice, kasha, and high fiber crackers (29
food codes). Refined grains were categorized by 40 food
codes which included white bread, French bread, rolls,
biscuits, bagels, pancakes and waffles, corubread, muffins
other than bran muffins, pasta, white rice, non-whole
grain cereals and crackers, and pretzels. Standard serving
sizes for grains were: two slices of bread; one biscuit,
bagel, piece of cornbread, or muffin; one-half cup pasta,
rice, or cooked cereals; one cup of dry cereals; and three
crackers.
The nuts and seeds group included nuts, seeds, and
butters made from nuts and seeds. Standard serving sizes
were one-quarter cup of nuts and seeds and two table-
spoons of butters.
Some plant foods included in mixed dishes (such as
vegetables in stews and mixed dishes) were not included
in these food groupings.
Other data
Other data used were age at the time of diagnosis or
selection, body mass index (BMI) (wt/hti for men and
w~/ht*~ for women) reported for the referent period, pres-
ence or absence of one or more first-degree relatives with
colorectal cancer, use of aspirin and/or nonsteroidal anti-
inflammatory drugs (NSAIDs) on a regular basis defined
as three times a week for at least one month, and long-term
vigorous leisure-time physical activity.2~a°'1 The BMI of
weight/height*~ was used for women because it has been
shown to be more independent of height than weight/
heightz among women." Information on tumor site was
obtained from local tumor registries and was classified as
proximal (cecum through transverse colon) or distal
(splenic flexure, descending, and sigmoid colon).
Statistical methods
The percentage of the total study population intake of
each nutrient contributed by plant foods was calculated.
We assessed nutrients for which plant foods contributed
over 50 percent of the nutrient in the diet. Because plant
foods are the major contributors of these nutrients, an
association observed with these nutrients could explain
possible biological mechanisms whereby plant foods are
associated with colon cancer risk. Because we are studying
plant foods, we have not included nutrients from supple-
ments; however, analyses conducted among nonusers of
supplements and users of supplements showed similar
patterns to those presented here. Adjustment for supple-
ment use did not alter our findings.
C~ncer Ca~se~ ~d Control. Vol 8. 1997 577

M.L. $1~ttery e~ al
The goal of the statistical analysis in this study was to
provide a point- and interval estimate of risk for plant
foods and their contributing nutrients. Thus, odds ratios
(OR) and 95 percent confidence intervals (CI) were
calculated from unconditional logistic regression models
which included the following adjustment variables: age
at selection; BMI; total energy intake and dietary calcium
(all treated as continuous variables); family history of
colorectal cancer (yes/no); long-term vigorous physical
activity (four exposure levels);.and use of aspirin and/or
NSAIDs (yes/no) treated as categorical variables. BMI
and physical activity were associated with colon cancer
in these data and also were associated with plant food
consumption; thus, they were used as adjustment factors
in these analyses. Total energy intake was used as an
adjustment variable rather than dietary fat, since, in these
data, dietary fat was not associated with risk of colon
cancer-although total energy intake increased risk of
colon cancerY To adjust adequately for total energy
intake, it was necessary also to adjust for dietary calcium.
Adjustment for other factors - such as cigarette smoking,
alcohol consumption, and vitamin/mineral supplement
use- did not alter our observations and are not included
in the final models. Similarly, adjustment for center (Utah,
Minnesota, or KPMCP) did not change the results, as
might be expected since case/control status was not
associated with the center.
For broad categories of plant foods, such as fruit, vege-
tables, and grains, foods were categorized based upon the
quintile distribution of servings in the gender-specific
control population. When looking at specific fruits and
vegetables, such as tomatoes, categories were derived
which represented meaningful eating patterns in this
population. Nutrients were categorized into quintiles
based upon the distribution of the control population for
men and women separately. Data on folic acid and B
vitamins were analyzed using density measures
(amount/I,000 kcal) since dietary recommendations are
based on caloric intake. For other nutrients, we assessed
the absolute amount of nutrients to determine if the
amount consumed was associated with colon cancer risk.
Age-specific analyses were performed using the median
age in the controls, 67 years, as the cut-point. Linear trend
associations were assessed from logistic regression modds
using the food or nutrient of interest as a continuous
variable. Interaction was assessed by the overall improved
fit of the logistic model with categorized interaction terms
in the model compared with those models without inter-
action te~s.z~
Results
The mean number of servings of fruits and vegetables
consumed by both men and women were approximately
two servings of fruits and three and one-half servings of
vegetables per day (Table 1). Men consumed slightly more
nuts and seeds, whole grain, and refined grain products
than women. We evaluated intake of soy products, such
as tofu, but because of the rarity with which these plant
foods were eaten, we were unable to evaluate associations
in a meaningful manner (96 percent of men and 98 percent
of women never ate soy products).
Increasing intake of vegetables was associated inversely
with colon cancer. Associations were strongest for older
men, younger women, and those with proximal tumors
(Table 2). High levels of whole grain consumption also
were associated with decreased risk of colon cancer among
men, with the strongest associations being for men who
were older at diagnosis (OR = 0.6, CI - 0.4-0.9) or had
distal tumors (OR = 0.7, CI = 0.5-1.0). Refined grains
slightly increased risk of colon cancer among men. Nut
and seed intakes were not associated with colon cancer
risk.
Among both men and women, higher levels of intake
of canned fruit were associated directly with risk of proxi-
mal tumors (Table 3). High intake of fresh fruit was
assodated with a slight nonsignificant reduction in risk
among women; among men, high intake of dried fruit
was associated with a 30 percent reduction of risk of distal
colon tumors. High levels of fruit juice were associated
with a slight increased risk of colon cancer;, we could not
identify any specific type of fruit juice which explained
this association. Further assessment of types of fresh fruit
(data not shown in table) showed a very modest non-
significant reduction in risk associated with eating three
or more apples/week relative to none (OR = 0.9 [CI =
0.7-1.1] for men and OR = 0.8 [CI = 0.7-1.1] for women).
Among women, we also observed the following associa-
tions: three or more citrus fruits/week relative to none
was associated with decreased risk (OR = 0.8, CI = 0.6-
1.0) and eating apricots on a weekly basis relative to none
was associated with decreased risk of proximal tumors
(OR = 0.6, CI = 0.4-0.8).
Specific vegetables which were associated inversely
with colon cancer were: dark yellow vegetables, tomatoes,
and salad greens (Table 4). Some differences by gender
and tumor site were observed, with dark yellow vegetables
being protective only in men, and tomatoes and salad
greens being more inversely associated with proximal
tumors. However, in all categories of vegetable consump-
tion, levels of intake were generally low, with the upper
group being four to five standard servings (a total of two
to two and one-half cups of vegetables) per week.
Plant foods contributed over 50 percent of several
nutrients, including vegetable protein, dietary fiber, ~=
carotene, vitamin C, folic acid, vitamin B6, thiamin, niacin,
copper, and iron in the diets of the study population (Table
5); these dietary, constituents were chosen for further
578 Cancer Causes and Control. Vol 8. 1997

Plant, foods and colon cancer
Table 1. Mean and standard deviation of plant foods and related nutrients in the US multicenter
study population
Men Women
Cases Controls Cases Controls
(n- 1,099) (n=~ 1,290) (n= 894) (n= 1,120)
Mean (SD) Mean (SO) Mean (SO) Mean (SD)
Foods (standard servings per day)
Fruits 2.0 (1.8) 2.0 (1.7)
2.0 (1.5) 2.0 (1.6)
Canned 0.4 (0.6) 0.4 (0.6)
0.4 (0.6) 0.4 (0.6)
Fresh 1.5 (1.5) 1.5 (1.3)
1.5 (1.2) 1.5 (1.2)
Dried 0.1 (0.4) 0.1 (0.3)
0.1 (0.3) 0.1 (0.6)
Vegetables 3.4 (2.7) 3.7" (2.9)
3.6 (2.7) 3.7 (2.9)
Legumes 0.2 (0.3) 0.2 (0.3)
0.1 (0.2) 0.1 (0.3)
Juice
Fruit 0.9 (1.0) 0.8 (1.1)
0.8 (0.9) 0,8 (0.9)
Vegetable 0.1 (0.3) 0.1 (0.3)
0.1 (0.2) 0.1 (0.3)
Grains
Whole 1.4 (1.1) 1.6 (1.3)
1.2 (0.8) 1.2 (0.9)
Refined 2.6 (1.6) 2.4 (1.6)
2.0 (1.3) 1.9 (1.3)
Nuts and seeds 0.5 (0.8) 0.5 (0.7)
0.3 (0.5) 0.3 (0.4)
Nutrients (Intake per day)
Total energy (kcal) 2,752 (1,218) 2,651 (1,197)
2,066 (913) 1,991 (858)
Vegetable protein(g) 33.2 (16.1) 33.1 (15.6)
26.8 (12.3) 26.6 (12.4)
Fiber (g)
Dietary fiber 26.5 (12.7) 27.0 (12.6)
22.8 (10.4) 22.9 (10.2)
Soluble fiber 8.9 (4.3) 9.1 (4.4)
7.7 (3.5) 7.7 (3.5)
Insoluble fiber 17.3 (8.5) 17.5 (8.2)
14.8 (6.9) 14.8 (6.7)
Pectin 3.4 (2.2) 3.5 (2.2)
3.1 (1.7) 3.1 (1.6)
Vitamins
~-c~rotene (mcg) 5,950 (6,808) 6,001 (5,036)
6,173 (5,106) 5,998 (5,042)
Vitamin C (mg) 170 (115) 172 (109)
167 (98) 167 (95)
Folic acid (mcg) 421 (208) 422 (201)
347 (156) 352 (159)
Pantothenic acid (rag) 6.5 (2.9) 6.5 (2.9)
5.2 (2.3) 5.2 (2.3)
Vitamin B~ (mg) 2.5 (1.1) 2.5 (1.1)
2.0 (0.8) 2.0 (0.8)
Thiamin (mg) 2.2 (1.0) 2.2 (0.9)
1.7 (0.8) 1.7 (0.7)
Riboflavin (rag) 2.7 (1.3) 2.7 (1.3)
2.1 (0.9) 2.1 (0.9)
Niacin (mg) 28.5 (12.4) 27.8 . (12.5)
21.5 (8.9) 21.2 (8.7)
Minerals
Potassium (rag) 4,225 (1,782) 4,243 (1,767)
3,546 (1,439) 3,548 (1,385)
Selenium (mcg) 155 (65) 152 (68)
120 (49) 118 (49)
Magnesium (rag) 446 (191) 448 (185)
356 (145) 355 (141)
Copper (mg) 2.0 (0.9) 2.0 (0.9)
1.6 (0.7) 1.6 (0.7)
Iron (mg) 18.9 (8.2) 18.7 (8.3)
14.9 (6.5) 14.6 (6.4)
Zinc (mg) 15.2 (6.9) 15.0 (7.1)
11.5 (5.3) 11.3 (5.0)
SD = standard deviation.
analyses. Whole grains were a major contributor of sde-
nium in the diet of the study population as indicated by
the database; however, vegetables were not. This may
indicate the difficul .ty of capturing accurate selenium
values, which are regionally variable, using standard
nutrient databases.
Total amounts of dietary, soluble and insoluble fiber,
~nd pectin were associated inversely with colon cancer
(Table 6). The strongest associations were observed for
those diagnosed at an older age and those with proximal
tumors. The association between total dietary fiber and
colon cancer was as good an indicator of risk as either
subtype of fiber, and, in many instances, the associations
were stronger with dietary fiber than its component sub-
types. The amount of dietary fiber per 1,000 kcal also was
associated with colon cancer (data not shown in table)
with associations being slightly stronger for men diag-
nosed at a younger age (OR = 0.7, CI = 0.5-1.1) and for
Cancer Cause~ and Contz'o|. Vo| ~. 1997 579

Table 2. Association between plant foods and colon cancer risk in the US multicenter study
population
Standard All subjects < 67 years 67+ years Distal
Proximal
servings/day OR= (Cl) OR: (CI) ORa (CI) OR= (CI) ORa
(CI)
Men (no. cases/controls)
Fruits:b ~ 0.7
0.7-1.3
1.4-1.9
2.0-2.9
2.9
P trend
Vegetables: < 1.5
1.6-2.5
2.6-3.4
3.5-5.2
5.2
P trend
Whole grains: < 0.5
0.6-1.0
1.1-1.6
1.7-2.3
2.3
P trend
Refined grains: < 1.1
1.2-1.8
1.8-2.6
2.7-3.4
> 3.4
P trend
Nuts and seeds: None
0.1 -O,5
0.6-1.0
1.0
P trend
Women (no. cases/controls)
Fruits:b ~; 0,9
1.0-1.4
1.5-2.0
2.1-3.0
3.0
P trend
Vegetables: < 1.7
1.8-2.6
2.7-3.7
3.8-5.2
5.2
P trend
Whole grains: < 0.5
0.6-0.9
1.0-1.3
1.4-1.9
1.9
P trend
1.099/1,290 542/645 557/645 542/I .290 526/1.290
1.0 -- 1.0 -- 1.0 -- 1.0 -- 1.0 --
1.1 (0.8-1.4) 1.1 (0.8-1.6) 1.0 (0.7-1.5) 1.1 (0.8-1.5) 1.1 (0.8-1.6)
1.1 (0.9-1.5) 1.1 (0.6-1.6) 1.1 (0.8-1.7) 1.0 (0.7-1.4) 1.3 (0.9-1.8)
1.1 (0.8-1.4) 1.2 (0.6-1.8) 1.0 (0.7-1.5) 0.9 (0.7-1.3) 1.4 (1.0-1.9)
1.1 (0.8-1.4) 1.2 (0.8-1.7) 0.9 (0.6-1.4) 1.1 (0.8-1.5) 1.1 (0.8L1.6)
0.74 0.56 0.24 0.58 0.98
1.0 -- 1.0 -- 1.0 -- 1.0 -- 1.0 --
1,1 (0,9-1.4) 1..4 (0,9-2,0) 0.9 (0.6-1.3) 1,0 (0,7-1.3) 1,2 (0,9-1,6)
1.0 (0.8-1.3) 1.0 (0.7-1.5) 1.0 (0.7-1.4) 0.9 (0.7-1.3) 1.0 (0.7-1.4)
0.9 (0.7-1.2) 1.0 (0.7-1.4) 0.9 (0.6-1.3) 1.0 (0.7-1.3) 0.9 (0.6-1.3)
0.7 (0.5-0,9) 0.9 (0.6-1.3) 0.6 (0.4-0.9) 0.8 (0.6-1.2) 0.6 (0.4-0.8)
< 0.01 0.06 0.02 0.10 < 0.01
1.o -- 1.o -- 1.o -- 1.o -- 1.o --
0.9 (0.7-1.1) 0.9 (0.6-1.3) 0.8 (0.6-1.1) 0.9 (0.7-1.3) 0.8 (0.6-1.1)
1.1 (0.8-1,4) 1.3 (0.9-1.8) 0.S (0.6-1.2) 0.9 (0.7-1.3) 1.2 (0.9-1.6)
0.9 (0.7-1.2) 1.0 (0.7-1.4) 0.S (0.6-1.1) 0.9 (0.7-1.3) 0.9 (0.7-1.3)
0.8 (0.6-1.0) 0.9 (0.6-1.4) 0.6 (0.4-0.9) 0.7 (0.5-1.0) 0.S (0.6-1.2)
0.02 0.26 0.02 0.04 0.14
1.0 i 1.0 -- 1.0 -- 1.0 i 1.0
1.4 (1,1-1.9) 1.8 (1.2-2.7) 1,2 (0.9-1.8) 1.5 (1,0-2.1) 1.5 (1,1-2.1)
1.5 (1,1-1.9) 1,8 (1.2-2.7) 1.2 (0.9-1.8) 1.6 (1.1-2.3) 1.4 (1.0-2.0)
1.2 (0.9-1.6) 1.4 (0.9-2.2) 1,2 (0.8-1.7) 1.4 (1.0-2.1) 1.1 (0,6-1.6)
1.5 (1.1-2.1) 1.8 (1.2-2.7) 1.4 (0.9-2.2) 1,8 (1.2-2.6) 1.5 (1,0-2.1)
0.30 0.32 0.62 0,22 0.52
1.0 -- 1.0 -- 1.0 ~ 1.0 ~ 1.0
1,1 (0.8-1.2) 0,9. (0.6-1.2) 1,1 (0.8-1.4) 1.0 (0.7-1.3) 1.0 (0.7-1.3)
1.0 (0.8-1,3) 1.1 (0.7-1.6) 1.0 (0.7-1.4) 1.1 (0.6-1.5) 1,0 (0.7-1.4)
1.1 (0.8-1.4) 1.0 (0.6-1.4) 1.2 (0.8-1.8) 1.2 (0.6-1.7) 1.0 (0.7-1.4)
0.98 0.74 0.82 0.96 0.88
894/1,120 4491543 4451577 429/1,120 44611,120
1.0 -- 1.0 -- 1.0 ~ 1.0 ~ 1.0
1.2 (0.9-1.5) 1.0 (0.6-1.4) 1.6 (1.0-2.4) 1.2 (0.8-1.7) 1.1 (0.6-1.6)
1.0 (0.7-1.3) 0.S (0.6-1.3) 1.2 (0.8-1.8) 1.0 (0.7-1.5) 0.9 (0.6-1.3)
1.0 (0.7-1.3) 0.7 (0.5-1.1) 1.5 (1.0-2.3) 1.0 (0.6-1.4) 1.0 (0.7-1.5)
1.0 (0.7-1.4) 0.8 (0.5-1.2) 1.4 (0.9-2.1) 1.1 (0.7-1.6) 1.0 (0.7-1.5)
0.54 0.34 0.84 0.76 0.64
1.0 -- 1.0 ~ 1.0 -- 1.0 -- 1.0
0.9 (0.7-1.1) 0.7 (0.4-1.1) 1.0 (0.7-1.5) 0.9 (0.6-1.3) 0.8 (0.6-1.2)
0.9 (0.7-1.2) 0.7 (0.4-1.0) 1.2 (0.8-1.7) 0.9 (0.6-1.3) 0.9 (0.6-1.2)
0.7 (0.5-1.0) 0.7 (0.4-1.0) 0.S (0.5-1.1) 0.7 (0.5-1.0) 0.7 (0.5-1.0)
0.7 (0.5-1.0) 0.6 (0.4-0.9) 0.8 (0.6-1.3) 0.8 (0.6-1.2) 0.6 (0.4-0.9)
0.04 0.24 0.04 0.42 0.02
1.0 -- 1.0 -- 1.0 -- 1.0 -- 1.0 --
1.4 (1.1-1.9) 1.5 (1.0-2.2) 1.3 (0.8-2.0) 1.4 (1.0-2.0) 1.4 (1.0-2.0)
1.3 (1.0-1.8) 1.3 (0.9-1.9) 1.3 (0.9-2.0) 1.4 (1.0-2.0) 1.3 (0.9-1.9)
1.4 (1.0-1.9) 1.4 (0.9-2.2) 1.4 (0.9-2.1) 1.6 (1.1-2.3) 1.2 (0.8-1.7)
1.0 (0.6-1.4) 1.1 (0.7-1.7) 1.0 (0.s-1.5) 1.2 (0.8-1.8) 0.9 (0.6-1.3).
0.56 0.92 0.42 0.56 0.18
580 Cancer Cause~ and Con~ro|. Vol 8. t997

Plans foods and colon cancer
Table 2. Continued
Standard All subjects < 67 years 67+ years
Distal Proximal
servings/day ORa (CI) ORa (Cl) ORa (CI)
ORa (CI) ORa (CI)
Refined grains: ~ 0.9 1.0 -- 1.0 -- 1.0 --
1.0 ~ 1.0 --
1.0-1.4 1.2 (0.9-1.6) 1.1 (0.7-1.8) 1,2 (0,8-1.8)
1.4 (0.9-2.0) 1.1 (0,7-1.5)
1.5-1.9 1.0 (0.7-1.4) 0.9 (0.6-1.4) 1.2 (0.8-1,8)
1.0 (0.7-1.5) 1.0 (0,7-1.5)
2.0-2.7 1.2 (0.9-1.6) 1.0 (0.6-1.6) 1.4 (0.9-2.2)
1.2 (0.8-1.7) 1.2 (0,8-1.7)
> 2.7 1.1 (0.8-1.6) 1.1 (0.6-1.6) 1.3 (0.8-2.1)
1.0 (0.7-1.6) 1.2 (0,7-1.8)
P trend 0.62 0.48 0.94
0.74 0.74
Nuts and seeds: None 1.0 -- 1.0 -- 1.0 --
1.0 ~ 1.0 --
0.1-0.2 1.2 (0.9-1,5) 1.4 (1.0-2.0) 1.1 (0.8-1.5)
0.9 (0.7-1.3) 1.5 (1,1-2.1)
0.3-0.5 1.0 (0.8-1.3) 1.2 (0.8-1.7) 0.9 (0.6-1.3)
0.8 (0.6-1.1) 1.3 (0,9-1.8)
> 0.5 1.0 (0.8-1.5) 1.3 (0.9-1.9) 0.8 (0.5-1.2)
0.9 (0.7-1.3) 1.2 (0.8-1.7)
P trend 0.52 0.48 0.94
0.74 0.74
OR = odds ratio; CI = 95% confidence interval. Model adjusted for age, body mass index (wtJht2 for
men, wt/htl's for women),
physical activity, use of aspirin/NSAID, presence or absence of a first-degree relative with
colorectal cancer, total energy
intake and calcium. Cut points based on quintile distribution in controls. Standard servings were
equivalent to one-half cup
of canned fruit, 1 medium piece of fresh fruit, one-quarter cup of dried fruit, one-half cup serving
of vegetables, 2 slices of
bread, 1 muffin, 1 biscuit, one-half cup pasta or rice, and one-quarter cup of nuts and seeds or 2
tbsp of peanut butter.
Fruit and vegetable categories do. not include juice.
distal tumors (OR = 0.6, CI = 0.4-0.9) than the compara-
ble values for absolute amount of fiber consumed; for
women, the associations when using density measures
(OR = 0.6, CI = 0.4-1.3 for proximal tumors) were similar
to those shown in Table 6. Dietary starch (data not shown
in table) was not associated statistically significandy with
colon Cance~
Associations between colon cancer and intake of other
nutrients contributed by plant foods showed the follow-
ing (Table 7): an inverse association for vegetable protein
~expressed as grams/I,000 kcal) among women, and an
inverse association for high intake of vitamin B6 and
thiamin, p-carotene was associated with an increased risk
among women with proximal tumors. Dietary potassium,
magnesium, selenium, iron, copper, and zinc were not
associated consistently significantly with altered risk of
colon cancer in either men or women (data not shown).
We assessed the associations of plant foods with colon
cancer after adjusting for types of fiber, vegetable protein,
vitamins, and minera~ls found in plant foods. Results for
aJl subjects are shown in Table 8. For the most part, there
vcere few differences observed between colon cancer risk
and plant foods with various types of adjustment.
Adjustment for dietary fiber slightly decreased the risk
associated with vegetables (OR = 0.7 when adjusted, and
0.8 when not adjusted) while adjustment of vegetables for
vitamins actually increased the protective association (OR
= 0.6 when adjusted for vitamins).
\V4"e assessed the interaction between having a family
history of a first-degree relative with colorectal cancer
and intake of plant foods. In general, associations were
as expected on an additive scale; plant foods were
protective for those with a family history of colorectal
cancer as well as for those without a family history of
colorectal cancer. We did observe, however, that low levels
of vegetable intake increased risk among those with a
family history of colorectal cancer beyond that expected
from the combined risk of family history of colorectal
cancer and low vegetable intake on either the additive or
multiplicative scales (Table 9). Among older women and
those with distal tumors, there was significant improved
fit of the model which included an interaction term for
family history and vegetable consumption (P = 0.04 for
both modds). Younger men who consumed a diet high
in refined grains and who had a family history' of colo-
rectal cancer had more than a sevenfold increase ~ risk
compared with men who only ate a diet high in refined
grains without a family history of colorectal (OR = 1.5)
or who had a family history of colorectal cancer but ate
low levels of refined grains (OR = 1.5). We observed no
interaction between family history of colorectal cancer
and consumption of other plant foods or nutrients
commonly found in plant foods.
Discussion
Results from this study corroborate the findings of many
other studies that increasing levels of vegetable intake are
associated with a decreased risk of colon cancer, especially,
for proximal tumors)"1° The associations between risk of
colon cancer and whole grains and fruit intake are less
consistent in the literature and in this population. We
observed that whole grains appeared protective for men,
especially those who were diagnosed at a younger age
Cancer Causes and Control. Vol 8. 1997 581

M.L Slattet~ ~ ~1
Table 3. Colon cancer risk associated with various types of fruits in the US multicenter study
population
No. (cases/controls) =
Men Women
All subjects Distal Proximal All subjects Distal
Proximal
ORa (Cl) ORa (CI) ORa (Cl) ORa (CI) OR= (Cl)
OR" (CI)
(I ,099/1,290) (542/1,290) (52611,290) (894/1,120) (42911 ,I 20)
(44611 ,I 20)
Canned~
None 1.0 ~ t.0 m 1.0 ~ 1.0 ~
1.0 ~ 1.0 m
0,1-0,6 1,0 (0,7-1.3) 0,8 (0,5-1,1) 1,3 (0,9-1,5) 1,1
(0,8-1,5) 1,1 (0,8-1,7) 1,0 (0,6-1,5)
0,7-1.8 0,9 (0,7-1.2) 0,8 (0,6-1,0) 1,2 (0,9-1,6) 1,1
(0,8-1,4) 0,9 (0,7-1,3) 1,2 (0,8-1,6)
1,9-4,2 1,0 (0,8-1,3) 0,8 (0,6-1,0) 1,4 (1,0-1.9) 1,0
(0,8-1,4) 0,9 (0,6-1,2) 1,1 (0,8-1,6)
> 4,2 1,2 (0,9-1,5) 0,8 (0,6.1,1) 1,6 (1,3-2,4) 1,2
(0,9-1,6) 1,0 (0,7-1,4) 1,4 (1,0-1.9)
P trend 0,90 0,14 0,16 0,44
0,50 0,30
Fresh
<3.8 1.0 -- 1.0 ~ 1.0 -- 1.0 --
1.0 -- 1.0 --
3.9-7.0 1.2 (0.9-1.5) 1.1 (0.8-1.5) 1.4 (1.0-1.9) 0.9
(0.7-1.3) 0.8 (0.6-1.2) 1.0 (0.7-1.5)
7.1-10.3 1.1 (0.8-1.4) 1.0 (0.7-1.36) 1.3 (0.9-1.8) 0.8
(0.6-1.1) 0.9 (0.6-1.2) 0.8 (0.6-1.2)
10.4-15.2 1.1 (0.5-1.4) 1.0 (0.7-1.37) 1.2 (0.9-1,7) 1.0
(0.7-1.3) 1.0 (0.7-1.4) 1.0 (0.7-1.4)
> 15.2 1.0 (0.8-1.3) 1.1 (0.8-1.45) 1.0 (0.7-1,5) 0.8
(0.6-1.1) 0.8 (0.6-1.2) 0.8 (0.6-1.2)
P trend 0.98 0.46 0.86 0.78
0.72 0.48
Dried
None 1.0 ~ 1.0 ~ 1.0 ~ 1.0 ~
1.0 ~ 1.0 ~
0.1-0.2 1.0 (0.6-1.8) 0.6 (0.3-1.4) 1.4 (0.8-2.7) 0.9
(0.6.1.4) 0.7 (0.4-1.4) 0.9 (0.5-1,6)
0.3-1,2 0.8 (0.7-1.0) 0.8 (0.6-1.1) 0.9 (0.6-1.2) 1.2
(0.9-1.6) 1.1 (0.8-1,S) 1.2 (0.9-1.7)
> 1,2 0,7 .(0,6-0,9) 0,6 (0,5-0,9) 0,8 (0,6-1,0) 1,3
(1,0-1,6) 1,3 (1,0-1,8) 1.3 (0,9-1,7)
P trend 0.10 0,02 0,96 0,54
0,96 0,44
Juice
~o.8 1.o -- 1.o -- 1.o -- 1,o --
1.o -- 1.o --
0.9-3.0 1,1 (0.8-1~4) 1.0 (0.7-1.4) 1.1 (0,8-1.5) 1.3
(0,9-1.7) 1.7 (0.2-2.5) 1.0 (0.7-1.5)
3.3-5.6 1.~. (1.1-1.9) 1.3 (0.9ol.7) 1.7 (1.2-2.4) 1.2
(0.9-1.6) 1.4 (0.9-2.0) 1.2 (0.8-1.7)
5.7-9.2 1,2 (0.9-1.5) 1.0 (0.7-1.3) 1.4 (1.0-2.00) 1.5
(1,1-1.9) 1.8 (1.2-2.6) 1.3 (0.9-1.8)
> 9.2 1.2 (0,9-1.6) 1.1 (0.8-1.6) 1.3 (0.9-1.8) 1.3
(1.0-1.7) 1.5 (1.0-2.2) 1.2 (0.5-1.7)
P trend 0.82 0.70 0.90 0.72
0.62 0.82
OR = odds ratio and CI = 95% confidence interval. Adjusted for age, body mass index (wtJht~ for men,
wt/htl"s for women),
lifetime vigorous leisure-time activity, presence or absence of a first-degree relative with
colorectal cancer, use of
aspirin/NSAIDs, dietary calcium, and energy intake.
Standard servings of fruits/week based on the quintile distribution in the controls and were
equivalent to one-half cup of
canned fruit, 1 piece of fresh fruit, one-quarter cup of dried fruit, and 6 oz. of juice.
and for those with distal tumors. We observed no asso-
ciation with total fruit intake, although cerr~dn types of
fruit, such as high consumption of dried fruit by men,
were associated inversely with colon cancer.
Plant foods are the custodians of numerous dietary
constituents, including vitamins, minerals, fiber, and other
potentially antic~rcinogerdc factors. The anticarcinogenic
properties of vegetables could be attributed, at least in
part, to fiber, vitamin, or mineral content, or to other
bioactive compounds. Dithiolthiones, glucosinolates,
indoles, isothiocyanates and thiocyanates, flavonoids, and
phenols found in plant foods, are potentially anficarcino-
genic.7 However, these bioactive compounds are
unavailable in standard nutrient databases, leaving assess-
ment of foods which contain these compounds as a
surrogate for their intake. Evaluation of specific fruits and
vegetables indicated food-specific associations with colon
cancer. Apricots, carrots, and tomatoes were associated
inversely with colon cancer, sugge.sting that carotenoids
such as lycopene may be protective for colon cancer.
Cruciferous vegetables have been associated with colon
cancer in some studies and, in this study, showed ordy a
slight inverse association. These vegetables contain
indoles and glucosinolates which have demonstrated
chemoprevendve potential from studies in animals and
call systems,zs Whether observed site-specific associations
for various fruit and vegetable groups suggest that specific
bioacdve components of fruits and vegetables have unique
properties and mechanisms which alter risk of colon
cancer or whether this is chance variation remains to be
elucidated.
The finding that canned fruit and iuice were associated
with a slight increased risk of colon cancer in both genders
suggests a possible role for sugar in colon caa'cinogenesis

Plant foods and colon cancer
Table 4. Colon cancer risk associated with various types of vegetables in the US multicenter study
population
standard servings/
week
No, (cases/controls) =
Men Women
All subjects Distal Proximal All subjects
01stal Proximal
OR" (Cl) OR= (Cl) OR" (Cl) OR" (Cl)
OR" (Cl) OR= (Cl)
(1,09911,290) (542/1,290) (526/1,290) (894/1,1 20)
(429/1,120) (44611,120)
"~egumes2
None 1.0 -- 1.0 ~ 1.0 ~
1.0 w 1.0 ~ 1.0 --
0.I-1.0 1,1 (0.9-1.4) 1.2 (0.9-1.5) 1.2
(0.9-1.6) 1.0 (0,6-1.3) 1.0 (0.7-1.3) 1.1 (0.8-1.4)
> 1.0 1,1 (0.9-1.4) 1.1 (0.8-1.4) 1.2
(0.9-1.7) 0.9 (0,7-1.1) 1.0 (0.7-1.3) 0.8 (0.6-1.1)
P trend 0,72 0.78 0.76
0.04 0.14 0.14
Dark yellow
None 1.0 -- 1.0 -- 1.0 --
1.0 -- 1.0 -- 1.0 --
0.1-1.5 0.9 (0.6-1.1) 0.8 (0.6-1.0) 1.0
(0.7-1.4) 1.0 (0.8-1.4) 1.2 (0.8-1.8) 0.9 (0.6-1.3)
1.6-4.0 0.9 (0.7-1.2) 0.8 (0.6-1.2) 1.0
(0.7-1.4) 1.0 (0.7-1.3) 1.1 (0.7-1.7) 0.9 (0.6-1.3)
4.0 0,7 (0.6-1.0) 0.7 (0.5-1.0) 0.8
(0.5-1.1) 0.9 (0.6-1.3) 1.1 (0.7-1.7) 0.8 (0.5-1.2)
P trend 0.14 0.28 0.34
0.28 0.96 0.18
Tomatoes
None 1.0 ~ 1.0 ~ 1.0 ~
1.0 ~ 1.0 ~ 1.0 ~
0.1-2.0 0.9 (0.7-~1.1) 0.8 (0.6-1.1)
0.9(0.8-1.2) 1.0 (0.8-1.3) 1.2 (0.8-1.7) 0.9 (0.6-1.2)
2.1-4.0 0.9 (0.7-1.1) 1.0 (0.7-1.4) 0.8
(0.6-1.1) 0.8 (0.6-1.1) 1,0 (0.6-1.5) 0.7 (0.5-1.0)
4.0 0.6 (0.4-0.8) 0.7 (0.5-1.1) 0.4
(0.3-0.7) 0.9 (0.6-1.3) 1,2 (0.8-1.9) 0.8 (0.5-1.2)
P trend 0.06 0.72 < 0.01
0.20 0,12 0.06
Cruciferous
None 1.0 -- 1.0 -- 1.0 --
1.0 -- 1.0 -- 1.0 ~
0.1-1.0 1.0 (0.8-1,4) 0.9 (0.6-1.3) 1.2
(0.6-1.7) 1.0 (0.7-1,5) 1.1 (0,7-1.8) 0.9 (0.6-1.4)
1.1-3.0 1.1 (0.9-1,5) 1.0 (0.7-1.4) 1.3
(0.9-1.8) 1.0 (0.7-1.4) 0.9 (0.6-1.5) 1.0 (0.7-1.5)
3.1-5.5 0.9 (0.7-1,2) 0.9 (0.6-1.2) 0.9
(0.6-1.4) 1.0 (0.7-1.4) 0.9 (0.6-1.4) 1.0 (0.7-1.6)
5.5 0.8 (0.6-1.1) 0.8 (0.6-1.2) 0.8
(0.5-1.1) 1.0 (0.7-1.8) 1.2 (0.7-13) 0.9 (0.6-1.4)
P trend 0.08 0.14 0.24
0.68 0.54 0.96
Salad greens
< 1.0 1.0 -- 1.0 -- 1.0 ~
1.0 ~ 1.0 ~ 1.0 ~
1.1-2.0 1.0 (0.8-1.3) 1,0 (0.7-1.4) 1.0
(0.7-1.4) 1.2 (0.8-1.6) 1.1 (0.7-1.7) 1.2 (0.8-1.7)
2.1-3.0 1.0 (0.7-1.3) 1,0 (0.7-1.5) 0.9
(0.6-1.3) 0.8 (0.6-1.1) 0.9 (0.6-1.3) 0.8 (0.5-1.2)
3.1-5.0 0.8 (0.6-1.0) 0.8 (0.6-1.1) 0.8
(0.6-1.1) 1.0 (0.7-1.3) 1.0 (0.7-1.4) 1.0 (0.7-1.4)
> 5,0 0.8 (0.6-1.1) 0.9 (0.7-1.3) 0.7
(0.5-0.9) 0.7 (0.5-1.0) 0.7 (0.5-1.0) 0.7 (0.5-1.0)
P trend 0.02 0.22 0.34
0.04 0.04 0.22
Vegetable juice
None 1.0 ~ 1.0 ~ 1.0 ~
1.0 -- 1.0 ~ 1.0 ~
0.1-1.0 1.0 (0.8-1.2) 0.9 (0.6-1.2) 1.1
(0.8-1.5) 0.9 (0.7-1.2) 0.8 (0.6-1,2) 1.0 (0.7-1.4)
> 1.0 1.2 (0.9-1.5) 1.1 (0.9-1.5) 1.3
(1.0-1.7) 1.2 (0.9-1.5) 1.2 (0.9-1,6) 1.2 (0.9-1.6)
~ trend 0.80 0.80 0.98
0.94 0.60 0.62
OR = odds ratio and CI = 95% confidence interval. Adjusted for age, body mass index (wt/ht~ for men,
wt/ht1"5 for women),
lifetime vigorous leisure-time activity, presence or absence of a first-degree relative with
colorectal cancer, use of
aspirin/NSAIDs, dietary calcium, and energy intake.
Legumes include bean soup, split peas, lentils and other dry beans; dark yellow vegetables include
carrots, winter squash,
yams: tomatoes include fresh, canned or cooked tomatoes; cruciferous includes cabbage, Brussels
sprouts, broccoli, parsnips,
rUtabagas, turnips, and cauliflower; salad greens include all types of lettuce, raw spinach, and
salad greens. Standard servings
per week were based on one-half cup of servings of legumes, dark yellow vegetables, tomatoes,
cruciferous vegetables, 1
cu~ of salad greens, and 6 oz. of vegetable juice.
rs
Causes ~d Control. VoI 8. 1997 583

Table 5. Percent of nutrients in the diet contributed by plant products in the US multicenter study
population
Men
Fruits Vegetables Whole Nuts Refined Total Fruits
Vegetables
grains grains
(%)" (%) (%) (%) (%) (%) (%)"
(%)
Worglel~
Whole
grains
(%)
Nuts
(%)
Refined
grains
(%)
Total
(%)
Energy 9.7 5.7 7.6
Vdgetable protein 8.1 16.6 20.5
Fiber (g)
Dietary fiber 18.7 23.1 20.1
Soluble fiber 22.6 23.7 14.3
Insoluble fiber 17.0 22.8 23.3
Pectin 39.5 30.9 1.4
Vitamins
J~-carotene 11.2 " 56.1 0.1
Vitamin C 51.2 25.2 3.0
Vitamin E 11.3 9.7 8.4
Folio acid 16.8 21.2 20.3
Pantothenic acid 9.9 13.8 8.0
Vitamin Be 18.0 15.2 15.0
Thiamin 9.7 10.1 18.8
Riboflavin 6.0 6.6 13.2
Niacin 4.9 8.2 16.6
Minerals
Potassium 7.3 1.3 13.9
Selenium 18.6 15.9 5.4
Magnesium 10.2 11.9 15,0
Copper 12.0 17.2 11.6
Iron 5.6 12.1 21.9
Zinc 2,6 8.1 12.9
3,6 12,5 39.1 12.9 7.0 8.0 2.9
12.3 43.1
9.5 26.9 81.6 10,2 19.6 20.9 7.3
25.2 83.2
4,5 11.6 78.0 22,4 26.3 19,3 3.2
10.6 81.8
2.5 13.9 77.0 27.0 26.8 13.3 1.7
12.4 81,2
4.9 10.6 78.6 20.5 25.9 22.7 3.5
9.8 82.4
6.1 0.7 78.6 44.2 35.1 1.2 3.9
0.6 85.0
0.1 0,4 67,8 12.2 61.8 0.1 < 0.1
0.3 74.4
0.1 2.2 81.6 54,6 27.7 3.0 < 0.1
1.7 87.0
13.4 5.0 47.8 14.5 12.4 8.8 10.0
4.9 50.6
3.5 13.0 74.8 19.4 25.8 18.1 2.6
11.4 77,3
3.3 8.0 43.0 12.7 16.8 8.1 2.4
7.6 47.6
2.3 8.5 59.0 22,4 18.8 13.1 1.7
7.6 63.6
2.9 22.4 63.9 12.3 12.5 18.5 2.1
21.1 66.5
1.1 13.4 40.3 7.9 8,8 12.6 0.8
12.6 42.7
5.3 17.9 52.9 6.5 10.4 16.1 4.4
17.1 54.5
1.3 21.3 45.1 6.0 4.8 15.0 0.9
20.8 47.5
2.6 3.9 46.4 21.9 18.9 5.1 1.9
3.6 51.4
6.8 7.6 51.5 12.9 14.3 15.0 5.0
7.2 54.4
8.1 8.9 57.8 15.4 20.4 11.6 5.8
7.8 61.0
2.5 19.9 62.0 7.3 14.6 21.8 1.9
19.4 65.0
4.2 7.8 35.6 3.6 9.5 13.2 3.2
7.8 37.3
Percent of total nutrient intake,
