Role of Fat, Animal Protein, and Dietary Fiber in Breast Cancer Etiology: A Case-Control Study2

Lubin, Flora; Wax, Yochanan; Modan, Baruch

doi:10.1093/jnci/77.3.605

Cited by 133 publications

(35 citation statements)

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“…The three most common foods for which risk estimates were given in these studies were determined (meat, milk and cheese) and used in the present metaanalysis. Two studies, which defined food groups in a manner that could not be adapted to this analysis, were excluded (Katsouyanni et al, 1986;Lubin et al, 1986). Risk estimates pertaining to the intake of these foods were obtained from a total of 36 papers (see Table 2 for references), 16 of which also contained relative risk estimates associated with total fat intake.…”

Section: Assembly Of Literaturementioning

confidence: 99%

Dietary fat and breast cancer risk revisited: a meta-analysis of the published literature

et al. 2003

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Animal experiments and human ecological studies suggest that dietary fat intake is associated with a risk of breast cancer, but individual-based studies have given contradictory results. We have carried out a meta-analysis of this association to include all papers published up to July 2003. Case -control and cohort studies that examined the association of dietary fat, or fat-containing foods, with risk of breast cancer were identified. A total of 45 risk estimates for total fat intake were obtained. Descriptive data from each study were extracted with an estimate of relative risk and its associated 95% confidence interval (CI), and were analysed using the random effects model of DerSimonian and Laird. The summary relative risk, comparing the highest and lowest levels of intake of total fat, was 1.13 (95% CI: 1.03 -1.25). Cohort studies (N ¼ 14) had a summary relative risk of 1.11 (95% CI: 0.99 -1.25) and case -control studies (N ¼ 31) had a relative risk of 1.14 (95% CI 0.99 -1.32). Significant summary relative risks were also found for saturated fat (RR, 1.19; 95% CI: 1.06 -1.35) and meat intake (RR, 1.17; 95% CI 1.06 -1.29). Combined estimates of risk for total and saturated fat intake, and for meat intake, all indicate an association between higher intakes and an increased risk of breast cancer. Case -control and cohort studies gave similar results. British Journal of Cancer (2003) Breast cancer is the leading cause of cancer death, and the most frequently diagnosed cancer in women worldwide (Lacey et al, 2002). Large differences in rates of the disease exist between countries, with higher rates in North America and Western Europe, and lower rates in Asia and South America (Lacey et al, 2002). These differences are likely to be due to environmental rather than genetic factors. The rates of breast cancer change in migrants from low-to high-risk countries, who eventually acquire the rates of their adopted country (Ziegler et al, 1993;Pike et al, 2002). Menstrual and reproductive risk factors for breast cancer do not appear to account for these differences in rates (Wu et al, 1996).The differences in dietary practices between countries are well established, and could contribute to the differences in breast cancer risk. Support for an influence of dietary fat on breast cancer rates comes from its effect on mammary carcinogenesis in animals, and human ecological data.Two major meta-analyses, combining results from over 140 studies examining the relationship between dietary fat and breast cancer risk in rats and mice, show dietary fat to be a promoter of mammary carcinogenesis (Fay et al, 1997). This effect is independent of the effects of caloric intake (Freedman et al, 1990). Human ecological studies show a strong correlation (0.7 or more) between dietary fat intake, estimated from national food balance data, and incidence and mortality of breast cancer worldwide. (Prentice and Sheppard, 1990).However, case -control and cohort studies that have examined the relationship between dietary fat and breast cancer risk...

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Section: Assembly Of Literaturementioning

confidence: 99%

Dietary fat and breast cancer risk revisited: a meta-analysis of the published literature

et al. 2003

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“…Case-control studies have shown low fibre intake, with or without high fat intake, to be associated with increased risk of breast cancer (Katsouyanni et al, 1986;Lubin et al, 1986;Howe et al, 1990;Zaridze et al, 1991). How such diets exert this influence has not been established, but one possibility is by an effect on oestrogen metabolism.…”

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Lower serum oestrogen concentrations associated with faster intestinal transit

Lewis

Heaton²,

Oakey³

et al. 1997

Br J Cancer

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Summary Increased fibre intake has been shown to reduce serum oestrogen concentrations. We hypothesized that fibre exerts this effect by decreasing the time available for reabsorption of oestrogens in the colon. We tested this in volunteers by measuring changes in serum oestrogen levels in response to manipulation of intestinal transit times with senna and loperamide, then comparing the results with changes caused by wheat bran. Forty healthy premenopausal volunteers were placed at random into one of three groups. The first group took senna for two menstrual cycles then, after a washout period, took wheat bran, again for two menstrual cycles. The second group did the reverse. The third group took loperamide for two menstrual cycles. At the beginning and end of each intervention a 4-day dietary record was kept and whole-gut transit time was measured; stools were taken for measurement of pH and j-glucuronidase activity and blood for measurement of oestrone and oestradiol and their non-protein-bound fractions and of oestrone sulphate. Senna and loperamide caused the intended alterations in intestinal transit, whereas on wheat bran supplements there was a trend towards faster transit. Serum oestrone sulphate fell with wheat bran (mean intake 19.8 g day-') and with senna; total-and non-protein-bound oestrone fell with senna. No significant changes in serum oestrogens were seen with loperamide. No significant changes were seen in faecal 3-glucuronidase activity. Stool pH changed only with senna, in which case it fell. In conclusion, speeding up intestinal transit can lower serum oestrogen concentrations.Keywords: intestinal transit; fibre; oestrogen; breast cancer There is substantial experimental, epidemiological and clinical evidence that breast cancer risk is influenced by endogenous hormones.Breast cancer is less common in rural Third World communities than in developed countries (Lea, 1966;Drasar and Irving, 1973;Armstrong and Doll, 1975;Miller, 1977) and becomes more common on migration from low-to high-risk areas, even within one generation (Staszewski and Haenszel, 1965;Buell, 1973), implying that environmental factors are important. Case-control studies have shown low fibre intake, with or without high fat intake, to be associated with increased risk of breast cancer (Katsouyanni et al, 1986;Lubin et al, 1986;Howe et al, 1990;Zaridze et al, 1991). How such diets exert this influence has not been established, but one possibility is by an effect on oestrogen metabolism.A high-fibre diet (Feng et al, 1993), or addition of wheat bran to the diet of healthy women (Rose et al, 1991), has been reported to reduce serum oestrogen levels. In rats given bran there was an increase in stool oestrogen (Neale, 1983). Vegetarians have higher faecal excretion and lower urinary excretion of oestrogens than omnivores (Armstrong et al, 1981;Goldin et al, 1982;Gorbach and Goldin, 1987). Plasma oestrogens have been found to be lower in vegetarians than omnivores in some (Shultz and Leklem, 1983) but not all studies (Goldin et al, ...

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“…The three most common food groups described in these studies were determined (meat, milk, cheese) and used in the present meta-analysis. Two studies which did not contain food groups defined in this way were excluded from the analysis (Lubin et al, 1986;Katsouyanni et al, 1986). Therefore, relative risk estimates pertaining to the intake of foods were obtained from a total of 19 papers (Ewertz & Gill, 1990;Hirohata et al, 1987;Hislop et al, 1986;Ingram et al, 1991;Kato et al, 1992;La Vecchia et al, 1987;Le et al, 1986;Lee et al, 1991;Lubin et al, 1981;Matos et al, 1991;Richardson et al, 1991;Talamini et al, 1984;Toniolo et al, 1989;Van't Veer et al, 1989;Hirayama, 1978;Kinlen, 1982;Mills et al, 1988;van den Brandt et al, 1993;Vatten et al, 1990).…”

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A meta-analysis of studies of dietary fat and breast cancer risk

et al. 1993

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Summary There is strong evidence that breast cancer risk is influenced by environmental factors, and animal experiments and human ecological data suggest that increased dietary fat intake increases the incidence of the disease. Epidemiological evidence on the relationship of dietary fat to breast cancer from cohort and case control studies has however been inconsistent. To examine the available evidence we have carried out a meta-anaylsis to summarise quantitatively the large published literature on dietary fat in the aetiology of breast cancer. After assembling all of the published case control and cohort studies, we extracted the relative risk in each study that compared the highest to the lowest level of intake. We then calculated a summary relative risk for all studies. The summary relative risk for the 23 studies that examined fat as a nutrient was 1.12 (95% CI 1.04-1.21). Cohort studies had a summary relative risk of 1.01 (95% CI 0.90-1.13) and case control studies a relative risk of 1.21 (95% CI 1.10-1.34). Summary estimates of risk for specific types of fat excluded unity for only saturated fat. For the 19 studies that examined food intake, the summary relative risks were 1.18 (95% CI 1.06-1.32) for meat, 1.17 (95% CI 1.04-1.31) for milk, and 1.17 (95% CI 1.02-1.36) for cheese. Summary relative risks for total fat intake were examined for several potential modifying factors. Regression analysis showed that European studies were more likely than studies done in other countries to show an increased relative risk associated with dietary fat and breast cancer, after taking into account potential modifying factors that included study design and quality.Breast cancer is the commonest cause of death from cancer in women in most of the Western world, and the leading cause of death from all causes among women aged less than 50 (Boring et al., 1993). Mortality from the disease has not changed appreciably over at least the period from 1950 to 1982(Bailar & Smith, 1986. There is however considerable evidence that breast cancer risk is influenced by environmental factors and is therefore in principle preventable.This evidence comes from the wide variation in breast cancer incidence observed between countries, from changing rates of disease in migrants from low risk to high risk countries and from changing rates of disease in some low risk countries. These observations make it plain that international differences in the frequency of breast cancer are not due to inherited differences between populations but rather are due to some difference in the environment.Differences in dietary practices could be the environmental factors responsible, and attention is directed to this possibility by two sources of information, the effect of dietary fat on mammary carcinogenesis in animals and by human ecological data.In animals, dietary fat acts as a promoter of mammary carcinogenesis and appears to have a specific effect on tumorigenesis in addition to the effect of increased intake of calories (see Welsch, 1986;Rogers & Lee, 1986...

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Role of Fat, Animal Protein, and Dietary Fiber in Breast Cancer Etiology: A Case-Control Study2

Cited by 133 publications

References 0 publications

Dietary fat and breast cancer risk revisited: a meta-analysis of the published literature

Dietary fat and breast cancer risk revisited: a meta-analysis of the published literature

Lower serum oestrogen concentrations associated with faster intestinal transit

A meta-analysis of studies of dietary fat and breast cancer risk

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