Diet and Nutrition:
Diet is known to play a role in the development of several chronic conditions
such as heart disease and a number of cancers. Studies examining the association
between diet and breast cancer specifically are not conclusive. Some dietary factors
that have been studied are phytoestrogen intake, daily nutrient intake, and
Many ecological studies have linked the low incidence rates of breast cancer
observed in Asian countries with the high levels of soyfood intake that is common in
these countries.1 Soyfoods contain isoflavones, a group of phytoestrogens, which
are known to have both weakly estrogenic and antiestrogenic activities.1,2
Isoflavones are suspected to increase levels of circulating Sex Hormone Binding
Globulin (SHBG) which binds to estrogens, thereby lowering levels of free estrogen.2
Although there is not sufficient evidence that soy or isoflavone consumption in
adulthood is protective for women in western countries, there is evidence that high
soy intake in adolescence reduces risk later in life.2
Antioxidants are known to counteract the oxidatitive processes that could
damage macromolecules such as proteins and DNA, thus contributing to the
prevention of degenerative diseases and cancers. Carotenoids, in particular, are
important antioxidants. The California Teacher’s Study found significant trends
between levels of antioxidant consumption and risk for developing breast cancer;
however, one study looking at serum levels of carotenoids found evidence of an
increase in breast cancer risk associated with decreasing levels of lutein, α-carotene,
β-carotene, and total carotenoids.3,4 No association has been drawn between serum
levels of retinol, lycopene, or zeaxanthin.4
Overall, the California Teacher’s Study found no association between total
caloric intake, total fat, carbohydrate, protein, or fiber intakes, fat-to-fiber ratio, or
carbohydrate-to-protein ratio and a woman’s risk of developing breast cancer.3
Although associations between dietary factors in adult life and breast cancer risk are
not strong or consistent, the effect of diet during puberty, adolescence, and early
adulthood may still have relevance to breast cancer risk.
1. Dai Q, Shu XO, Jin F, Potter JD, Kushi LH, Teas J, Gao YT, Zheng W.
2001. Population-based case-control study of soyfood intake and breast
cancer risk in Shanghai. Br J Cancer. 85(3): 372-8.
2. Adlercreutz H. 2002. Phyto-oestrogens and breast cancer. Lancet Oncol.
3. Horn-Ross PL, Hoggatt KJ, West DW, Krone MR, Stewart SL, Anton-Culver
H, Bernstein L, Deapen D, Peel D, Pinder R, Reynolds P, Ross RK, Wright
W, Ziogas A. 2002. Recent diet and breast cancer risk: the California
Teachers Study (USA). Cancer Causes Control. 13(5): 407-15.
4. Toniolo P, Van Kappel AL, Akhmedkhanov A, Ferrari P, Kato I, Shore RE,
Riboli E. 2001. Serum carotenoids and breast cancer. Am J Epidemiol.
Diet and Nutrition:
1: Cancer Causes Control 2002 Jun;13(5):407-15
Recent diet and breast cancer risk: the California Teachers Study (USA).
Horn-Ross PL, Hoggatt KJ, West DW, Krone MR, Stewart SL, Anton-Culver H,
Bernstein L, Deapen D, Peel D, Pinder R, Reynolds P, Ross RK, Wright W, Ziogas A.
Northern California Cancer Center, Union City 94587, USA. email@example.com
OBJECTIVE: The impact, if any, on breast cancer risk of modifying adult dietary
intake is an area of much interest. We take the opportunity to address the
relationship between recent adult diet and breast cancer risk during the first two
years of follow-up of the large California Teachers Study cohort. METHODS: Of the
111.526 at-risk cohort members who resided in California and completed a baseline
dietary assessment, 711 were diagnosed with invasive breast cancer after joining the
cohort and before January 1998. Average daily nutrient intake was computed based
on a food-frequency questionnaire assessing usual dietary intake and portion size
during the year prior to joining the cohort. Incident breast cancers were identified
through the California Cancer Registry and follow-up for death and confirmation of
continued California residence utilized a variety of data sources. Cox proportional
hazards models were used to calculate relative hazards. RESULTS: The following
components of recent dietary intake were not associated with breast cancer risk:
energy, fat, fiber, antioxidant vitamins, and phytoestrogens. Only recent average
alcohol consumption of 20 or more grams per day (approximately two or more
glasses of wine) was associated with increased risk (RR= 1.5, 95% CI: 1.2-2.0
compared to non-drinkers; P(trend) = 0.01 across quintiles). CONCLUSION: With the
exception of alcohol consumption, this study provides no evidence that recent
macro- or micronutrient composition of adult diet is likely to have a direct effect on
breast cancer risk. Some reduction of alcohol consumption among those consuming
more than one drink per day may be beneficial.
PMID: 12146845 [PubMed - in process]
2: Lancet Oncol 2002 Jun;3(6):364-73
Phyto-oestrogens and cancer.
Institute for Preventive Medicine, Nutrition, and Cancer, Folkhalsan Research Center,
Division of Clinical Chemistry, University of Helsinki, Helsinki, Finland.
Phyto-oestrogens have been suggested to have a preventive effect against various
cancers. This review includes a discussion of the consumption of phyto-oestrogen-
rich foods such as soy, a source of isoflavones, and whole grain products, which
contain lignans, and their role in the prevention of breast, prostate, and colon
cancer. In women, a soy-containing diet is only slightly protective against breast
cancer, if at all, but is more likely to be beneficial if initiated before puberty or during
adolescence. These findings are supported by conclusions of studies of immigrants
and other epidemiological studies. However, in one case-control study and one
prospective study, a low-lignan diet increased the risk of breast cancer. Experimental
evidence also exists for an inhibitory effect of soy and rye bran on prostate-cancer
growth and for rye bran or isolated lignans on colon cancer. Whether these observed
protective effects are caused by the presence of dietary phyto-oestrogens, or
whether they are merely indicators of a healthy diet in general, has not been
PMID: 12107024 [PubMed - indexed for MEDLINE]
3: Ann N Y Acad Sci 2002 Jun;963:247-67
Diet and breast cancer.
Bradlow HL, Sepkovic DW.
David and Alice Jurist Institute for Research, Hackensack University Medical Center,
Hackensack, New Jersey 07601, USA. firstname.lastname@example.org
The preponderance of evidence suggests a role for fat and alcohol as risk factors for
breast cancer. The role of milk is more controversial with some studies suggesting
that milk is a risk factor and others that consumption of milk is protective against
breast cancer. No other major nutrient appears to play a significant role in increasing
breast cancer risk. On the other hand, there is increasing evidence that a variety of
micronutrients and hormones appear to have significant anticancer activity. These
range from steroids such as dehydroepiandrosterone (DHEA) and its analysis to
indoles, isothiocyanates, and isoflavone derivatives. These compounds act directly by
interfering with cyclins and promoting apoptosis as well as indirectly by altering
estrogen metabolism in a favorable direction. These effects are not merely
theoretical actions in cell culture and tissue explants; they have been demonstrated
in human patients as a range of studies have demonstrated.
PMID: 12095951 [PubMed - indexed for MEDLINE]
4: Int J Cancer 2002 May 10;99(2):238-44
Lifelong vegetarianism and risk of breast cancer: a population-based case-
control study among South Asian migrant women living in England.
Dos Santos Silva I, Mangtani P, McCormack V, Bhakta D, Sevak L, McMichael AJ.
Department of Epidemiology and Population Health, London School of Hygiene and
Tropical Medicine, London, England. email@example.com
To investigate the role of lifelong vegetarianism on the aetiology of female breast
cancer, we conducted a population-based case-control study among South Asian
migrant women from the Indian subcontinent resident in England. A total of 240
South Asian breast cancer cases were identified from 2 cancer registries during
1995-1999. For each case, 2 age-matched South Asian controls were randomly
selected from the age-sex register of the case practice. Lifelong vegetarians had a
slight reduction, although not statistically significant, in the odds of breast cancer
relative to lifelong meat-eaters, which persisted after adjustment for socio-
demographic and reproductive variables [odds ratio (OR)=0.77; 95% confidence
interval (CI)=0.50-1.18]. Analysis by food group revealed no linear trend in the odds
of breast cancer with increasing consumption of meat (p=0.10) but the odds were
higher for women in the top 75%. In contrast, there were strong inverse trends in
the odds of breast cancer with increasing intake of vegetables (p=0.005), pulses
(p=0.007) and fibre [non-starch polysaccharides, NSP (p=0.02)], with women in the
highest 25% of intake of these foods having about 50% of the odds of those in the
lowest ones. Adjustment for intake of vegetables and pulses reverted the odds of
breast cancer in lifelong vegetarians relative to lifelong meat-eaters (OR=1.04; 95%
CI=0.65-1.68) and attenuated the quartile-specific estimates for meat intake,
whereas the inverse trends in the odds of breast cancer with intake of vegetables
and pulses remained after adjustment for type of diet or meat intake. These findings
suggest that lifelong vegetarianism may be associated with a reduction in the risk of
breast cancer through its association with a higher intake of vegetables and pulses.
Although it is not possible to exclude the possibility that lifelong meat abstention
may also play a role, the findings provide evidence that a diet rich in vegetables and
pulses, such as those typically found in South Asian diets, may be protective against
Copyright 2002 Wiley-Liss, Inc.
PMID: 11979439 [PubMed - indexed for MEDLINE]
5: Cancer Res 2001 Oct 1;61(19):7136-41
Dietary folate intake and breast cancer risk: results from the Shanghai
Breast Cancer Study.
Shrubsole MJ, Jin F, Dai Q, Shu XO, Potter JD, Hebert JR, Gao YT, Zheng W.
Division of General Internal Medicine and Vanderbilt-Ingram Cancer Center,
Vanderbilt University, Nashville, Tennessee 37232, USA.
Folate is involved in DNA synthesis, repair, and methylation. It has been
hypothesized that high intake of folate may reduce the risk of human cancers,
including cancer of the breast. Using data from a population-based case-control
study of breast cancer conducted in urban Shanghai during 1996-1998, we evaluated
the association of dietary folate intake and breast cancer risk among 1321 cases and
1382 controls, 25-64 years of age, who never drank alcohol regularly or used
vitamin supplements. Usual dietary habits were assessed with an in-person,
interviewer-administered food frequency questionnaire developed and tested for use
in this population. Unconditional logistic regression models were used to calculate
odds ratios (ORs) and their 95% confidence intervals (95% CIs) after adjusting for
potential confounding factors. Dietary folate intake was inversely associated with
breast cancer risk (P for trend, 0.05) with an adjusted OR of 0.71 (95% CI, 0.56-
0.92) observed among women who were in the highest quintile of intake. The
inverse association was stronger after further adjusting for total fruit and vegetable
and animal food intakes (OR, 0.62; 95% CI, 0.46-0.82; P for trend, 0.01). A more
pronounced inverse association between folate intake and breast cancer risk (OR,
0.47; 95% CI, 0.25-0.88; P for trend, 0.01) was observed among women who
consumed high levels of folate cofactors (methionine, vitamin B(12), and vitamin
B(6)) than those whose intake levels of these nutrients were low. Dietary intake of
methionine, vitamin B(12), and vitamin B(6) were not independently related to risk
of breast cancer after adjusting for confounding factors. Thus, our study adds
additional support to the protective role of dietary folate in breast carcinogenesis and
suggests further that the effect of folate may be modified by dietary intake of
methionine, vitamin B(12), and vitamin B(6).
PMID: 11585746 [PubMed - indexed for MEDLINE]
6: Br J Cancer 2001 Aug 3;85(3):372-8
Population-based case-control study of soyfood intake and breast cancer
risk in Shanghai.
Dai Q, Shu XO, Jin F, Potter JD, Kushi LH, Teas J, Gao YT, Zheng W.
Vanderbilt-Ingram Cancer Center and Department of Medicine, Vanderbilt University,
Nashville, TN, 37232-8300, USA.
We evaluated the association of soyfood intake and breast cancer risk in a
population-based case-control study among Chinese women in Shanghai. Included in
the study were 1459 cases and 1556 age-matched controls, with respective response
rates of 91.1% and 90.3%. Usual soyfood intake was assessed using a food
frequency questionnaire (FFQ). Separate analyses were performed for all subjects
and for the subset who reported no recent change in soyfood intake. The intake
levels of soyfoods among women in Shanghai are high, with 96.6% women reporting
soyfood consumption at least once a week. A statistically non-significant reduced risk
(odds ratio (OR) = 0.78 95% CI = 0.52-1.16) of breast cancer was observed among
those who reported eating soyfood at least once a week. Compared to those in the
lowest decile intake group, women in the highest decile intake group had a 30%
reduced risk of breast cancer (OR = 0.66, 95% CI = 0.46-0.95), but no monotonic
dose-response relation was observed (P for trend, 0.28). Stratified analyses showed
that the inverse association was restricted primarily among women who had a high
body mass index (BMI), with an adjusted OR of 0.30 (95% CI = 0.10-0.94) observed
for the highest intake group. The reduction in risk was stronger for breast cancer
positive for both oestrogen receptor (ER) and progesterone receptor (PR) (OR =
0.44, 95% CI = 0.25-0.78) than those with other ER/PR status. More pronounced
inverse associations were observed in analyses among those who reported no recent
change in soyfood intake than those conducted in all subjects. A dose-response
relation between soyfood intake and breast cancer risk was observed in this subset
of women (P for trend, 0.02), with an OR of 0.46 (95%CI = 0.28-0.75) for those in
the highest decile intake group. No clear monotonic dose-response relation was
found between soyfood intake and breast cancer risk among regular soy eaters, but
nevertheless the results suggest that regular soyfood consumption may reduce the
risk of breast cancer, particularly for those positive for ER and PR; the effect may be
modified by body mass index. Copyright 2001 Cancer Research Campaign.
PMID: 11487268 [PubMed - indexed for MEDLINE]
7: Am J Epidemiol 2001 Jun 15;153(12):1142-7
Serum carotenoids and breast cancer.
Toniolo P, Van Kappel AL, Akhmedkhanov A, Ferrari P, Kato I, Shore RE, Riboli E.
Department of Obstetrics and Gynecology, New York University School of Medicine,
New York, NY 10016, USA. firstname.lastname@example.org
The consumption of vegetables and fruit may protect against many types of cancer,
but research evidence is not compelling for breast cancer. Carotenoids are pigments
that are present in most plants and have known antioxidant properties. Blood
concentrations of carotenoids have been proposed as integrated biochemical markers
of vegetable, fruit, and synthetic supplements consumed. In a case-control study
(270 cases, 270 controls) nested within a cohort in New York during 1985-1994, the
carotenoids lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, and
beta-carotene were measured in archived serum samples using liquid
chromatography. There was an evident increase in the risk of breast cancer for
decreasing beta-carotene, lutein, alpha-carotene, and beta-cryptoxanthin. The risk of
breast cancer approximately doubled among subjects with blood levels of beta-
carotene at the lowest quartile, as compared with those at the highest quartile (odds
ratio = 2.21; 95% confidence interval (CI): 1.29, 3.79). The risk associated with the
other carotenoids was similar, varying between 2.08 (95% CI: 1.11, 3.90) for lutein
and 1.68 (95% CI: 0.99, 2.86) for beta-cryptoxanthin. The odds ratio for the lower Download full-text
quartile of total carotenoids was 2.31 (95% CI: 1.35, 3.96). These observations offer
evidence that a low intake of carotenoids, through poor diet and/or lack of vitamin
supplementation, may be associated with increased risk of breast cancer and may
have public health relevance for people with markedly low intakes.
PMID: 11415946 [PubMed - indexed for MEDLINE]