Dietary Intervention Studies of Colorectal Cancer

AbstractMicrobiome research in the last two decades has delivered as a key finding that the human intestine hosts a unique and complex ecosystem with many variables affecting the composition of the microbiota and in turn its function in metabolism and immune defence. Hundreds of external (environmental) factors have meanwhile been identified as significantly associated with bacterial biomass and diversity and, amongst these, diet is considered as a key determinant of microbial populations. However, dietary intervention studies, including those with fermentable substrates that have bulk effects on bowel functions, have revealed only very minor effects on overall microbiome composition and usually show only a very few species changing in population size. What that means in the context of hundreds of different species coexisting in competition or mutualism in the human colon is far from understood. This review addresses some of the current limits in research on diet effects by taking anatomical and physiological features of the intestine into consideration. It also provides some recommendations on future human studies needed to assess how the diet influences the microbiome and associated effects on metabolic health.

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A Review of Breast, Cervical, and Colorectal Cancer Screening Interventions in Older Women

Cancer Control ◽

10.1177/1073274805012004s09 ◽

2005 ◽

Vol 12 (4_suppl) ◽

pp. 58-69 ◽

Cited By ~ 9

Author(s):

Janice V. Bowie ◽

Barbara A. Curbow ◽

Mary A. Garza ◽

Erin K. Dreyling ◽

Lisa A. Benz Scott ◽

...

Keyword(s):

Colorectal Cancer ◽

Cancer Screening ◽

Older Women ◽

Colorectal Cancer Screening ◽

Intervention Studies ◽

The United States ◽

Community Based ◽

Screening Guidelines ◽

Periodic Testing ◽

Effective Community

Although cancer-screening guidelines recommend periodic testing for women 50 years of age and older, these tests are underused. A search of databases identified 156 community-based breast, cervical, and colorectal cancer screening intervention studies published before April 2003. Most were conducted in the United States. More than half used randomization procedures or pre-post measures, and one third used both. Most reported significant intervention effects. Cervical and combined cervical and breast studies had higher rates of pre-post designs, and breast studies had the highest percentage using randomization. Although effective community-based breast and cervical interventions have been conducted, there is an urgent need for amplification of colorectal cancer screening.

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Calcium Bioavailability in Relation to Bone Health

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831.72.1.13 ◽

2002 ◽

Vol 72 (1) ◽

pp. 13-18 ◽

Cited By ~ 16

Author(s):

Susan J. Fairweather-Tait ◽

Birgit Teucher

Keyword(s):

Bone Health ◽

Bone Growth ◽

Intervention Studies ◽

Dietary Intervention ◽

Calcium Absorption ◽

Dietary Calcium ◽

Whole Body ◽

Calcium Balance ◽

Calcium Bioavailability

A well established stable isotope technique exists for measuring calcium absorption from single foods and meals, but the long term effects of calcium on bone health cannot be assessed from acute bioavailability studies. Bone health depends primarily on the degree of mineralization, measured as bone mineral density (BMD), and phenotypic variations depend on genetic and environmental factors including calcium supply. Since almost all retained calcium is used for bone mineralization and remodeling, BMD can be used as a long-term (> six months) marker of dietary calcium bioavailability. However, BMD is a very insensitive marker of calcium bioavailability, so its use in dietary intervention studies is restricted to periods of significant bone growth or loss. Biochemical markers of bone metabolism may be used to predict the overall bioavailability of dietary calcium over a shorter time period (> four weeks), but they have a high coefficient of variation, so may not be appropriate for some dietary intervention studies. A group of European laboratories is currently developing an alternative approach using a long-lived radioisotope (41Ca) to label bone calcium and to directly measure the rate of calcium loss from urinary excretion data. The efficiency of calcium absorption is inversely related to intake; whole body balance of the mineral is dependent on rates of absorption and excretion and limited by calcium-binding substances in the gut. Dietary data and indirect measures of bone health indicate that bioavailability is important when habitual intakes are low, especially during periods of bone growth or loss. Further research is required to quantify the effects of major dietary modulators of calcium balance on bone health and to understand their relationship with genetic and physiological variables.

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Resistant starch supplementation increases crypt cell proliferative state in the rectal mucosa of older healthy participants

British Journal Of Nutrition ◽

10.1017/s0007114520001312 ◽

2020 ◽

Vol 124 (4) ◽

pp. 374-385

Author(s):

Fiona C. Malcomson ◽

Naomi D. Willis ◽

Iain McCallum ◽

Long Xie ◽

Arthur C. Ouwehand ◽

...

Keyword(s):

Colorectal Cancer ◽

Cell Cycle ◽

Resistant Starch ◽

Dietary Intervention ◽

Controlled Trial ◽

Rectal Mucosa ◽

Crypt Cell ◽

Post Intervention ◽

Double Blind ◽

Healthy Participants

AbstractThere is strong evidence that foods containing dietary fibre protect against colorectal cancer, resulting at least in part from its anti-proliferative properties. This study aimed to investigate the effects of supplementation with two non-digestible carbohydrates, resistant starch (RS) and polydextrose (PD), on crypt cell proliferative state (CCPS) in the macroscopically normal rectal mucosa of healthy individuals. We also investigated relationships between expression of regulators of apoptosis and of the cell cycle on markers of CCPS. Seventy-five healthy participants were supplemented with RS and/or PD or placebo for 50 d in a 2 × 2 factorial design in a randomised, double-blind, placebo-controlled trial (the Dietary Intervention, Stem cells and Colorectal Cancer (DISC) Study). CCPS was assessed, and the expression of regulators of the cell cycle and of apoptosis was measured by quantitative PCR in rectal mucosal biopsies. SCFA concentrations were quantified in faecal samples collected pre- and post-intervention. Supplementation with RS increased the total number of mitotic cells within the crypt by 60 % (P = 0·001) compared with placebo. This effect was limited to older participants (aged ≥50 years). No other differences were observed for the treatments with PD or RS as compared with their respective controls. PD did not influence any of the measured variables. RS, however, increased cell proliferation in the crypts of the macroscopically-normal rectum of older adults. Our findings suggest that the effects of RS on CCPS are not only dose, type of RS and health status-specific but are also influenced by age.

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